// Algorithm implementation -*- C++ -*-
	
	// Copyright (C) 2001-2013 Free Software Foundation, Inc.
	//
	// This file is part of the GNU ISO C++ Library.  This library is free
	// software; you can redistribute it and/or modify it under the
	// terms of the GNU General Public License as published by the
	// Free Software Foundation; either version 3, or (at your option)
	// any later version.
	
	// This library is distributed in the hope that it will be useful,
	// but WITHOUT ANY WARRANTY; without even the implied warranty of
	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	// GNU General Public License for more details.
	
	// Under Section 7 of GPL version 3, you are granted additional
	// permissions described in the GCC Runtime Library Exception, version
	// 3.1, as published by the Free Software Foundation.
	
	// You should have received a copy of the GNU General Public License and
	// a copy of the GCC Runtime Library Exception along with this program;
	// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
	// <http://www.gnu.org/licenses/>.
	
	/*
	 *
	 * Copyright (c) 1994
	 * Hewlett-Packard Company
	 *
	 * Permission to use, copy, modify, distribute and sell this software
	 * and its documentation for any purpose is hereby granted without fee,
	 * provided that the above copyright notice appear in all copies and
	 * that both that copyright notice and this permission notice appear
	 * in supporting documentation.  Hewlett-Packard Company makes no
	 * representations about the suitability of this software for any
	 * purpose.  It is provided "as is" without express or implied warranty.
	 *
	 *
	 * Copyright (c) 1996
	 * Silicon Graphics Computer Systems, Inc.
	 *
	 * Permission to use, copy, modify, distribute and sell this software
	 * and its documentation for any purpose is hereby granted without fee,
	 * provided that the above copyright notice appear in all copies and
	 * that both that copyright notice and this permission notice appear
	 * in supporting documentation.  Silicon Graphics makes no
	 * representations about the suitability of this software for any
	 * purpose.  It is provided "as is" without express or implied warranty.
	 */
	
	/** @file bits/stl_algo.h
	 *  This is an internal header file, included by other library headers.
	 *  Do not attempt to use it directly. @headername{algorithm}
	 */
	
	#ifndef _STL_ALGO_H
	#define _STL_ALGO_H 1
	
	#include <cstdlib>             // for rand
	#include <bits/algorithmfwd.h>
	#include <bits/stl_heap.h>
	#include <bits/stl_tempbuf.h>  // for _Temporary_buffer
	
	#if __cplusplus >= 201103L
	#include <random>     // for std::uniform_int_distribution
	#include <functional> // for std::bind
	#endif
	
	// See concept_check.h for the __glibcxx_*_requires macros.
	
	namespace std _GLIBCXX_VISIBILITY(default)
	{
	_GLIBCXX_BEGIN_NAMESPACE_VERSION
	
	  /// Swaps the median value of *__a, *__b and *__c to *__result
	  template<typename _Iterator>
	    void
	    __move_median_to_first(_Iterator __result, _Iterator __a,
				   _Iterator __b, _Iterator __c)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_LessThanComparableConcept<
		    typename iterator_traits<_Iterator>::value_type>)
	
	      if (*__a < *__b)
		{
		  if (*__b < *__c)
		    std::iter_swap(__result, __b);
		  else if (*__a < *__c)
		    std::iter_swap(__result, __c);
		  else
		    std::iter_swap(__result, __a);
		}
	      else if (*__a < *__c)
	      	std::iter_swap(__result, __a);
	      else if (*__b < *__c)
		std::iter_swap(__result, __c);
	      else
		std::iter_swap(__result, __b);
	    }
	
	  /// Swaps the median value of *__a, *__b and *__c under __comp to *__result
	  template<typename _Iterator, typename _Compare>
	    void
	    __move_median_to_first(_Iterator __result, _Iterator __a,
				   _Iterator __b, _Iterator __c,
				   _Compare __comp)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_BinaryFunctionConcept<_Compare, bool,
		    typename iterator_traits<_Iterator>::value_type,
		    typename iterator_traits<_Iterator>::value_type>)
	
	      if (__comp(*__a, *__b))
		{
		  if (__comp(*__b, *__c))
		    std::iter_swap(__result, __b);
		  else if (__comp(*__a, *__c))
		    std::iter_swap(__result, __c);
		  else
		    std::iter_swap(__result, __a);
		}
	      else if (__comp(*__a, *__c))
		std::iter_swap(__result, __a);
	      else if (__comp(*__b, *__c))
		std::iter_swap(__result, __c);
	      else
		std::iter_swap(__result, __b);
	    }
	
	  // for_each
	
	  /// This is an overload used by find() for the Input Iterator case.
	  template<typename _InputIterator, typename _Tp>
	    inline _InputIterator
	    __find(_InputIterator __first, _InputIterator __last,
		   const _Tp& __val, input_iterator_tag)
	    {
	      while (__first != __last && !(*__first == __val))
		++__first;
	      return __first;
	    }
	
	  /// This is an overload used by find_if() for the Input Iterator case.
	  template<typename _InputIterator, typename _Predicate>
	    inline _InputIterator
	    __find_if(_InputIterator __first, _InputIterator __last,
		      _Predicate __pred, input_iterator_tag)
	    {
	      while (__first != __last && !bool(__pred(*__first)))
		++__first;
	      return __first;
	    }
	
	  /// This is an overload used by find() for the RAI case.
	  template<typename _RandomAccessIterator, typename _Tp>
	    _RandomAccessIterator
	    __find(_RandomAccessIterator __first, _RandomAccessIterator __last,
		   const _Tp& __val, random_access_iterator_tag)
	    {
	      typename iterator_traits<_RandomAccessIterator>::difference_type
		__trip_count = (__last - __first) >> 2;
	
	      for (; __trip_count > 0; --__trip_count)
		{
		  if (*__first == __val)
		    return __first;
		  ++__first;
	
		  if (*__first == __val)
		    return __first;
		  ++__first;
	
		  if (*__first == __val)
		    return __first;
		  ++__first;
	
		  if (*__first == __val)
		    return __first;
		  ++__first;
		}
	
	      switch (__last - __first)
		{
		case 3:
		  if (*__first == __val)
		    return __first;
		  ++__first;
		case 2:
		  if (*__first == __val)
		    return __first;
		  ++__first;
		case 1:
		  if (*__first == __val)
		    return __first;
		  ++__first;
		case 0:
		default:
		  return __last;
		}
	    }
	
	  /// This is an overload used by find_if() for the RAI case.
	  template<typename _RandomAccessIterator, typename _Predicate>
	    _RandomAccessIterator
	    __find_if(_RandomAccessIterator __first, _RandomAccessIterator __last,
		      _Predicate __pred, random_access_iterator_tag)
	    {
	      typename iterator_traits<_RandomAccessIterator>::difference_type
		__trip_count = (__last - __first) >> 2;
	
	      for (; __trip_count > 0; --__trip_count)
		{
		  if (__pred(*__first))
		    return __first;
		  ++__first;
	
		  if (__pred(*__first))
		    return __first;
		  ++__first;
	
		  if (__pred(*__first))
		    return __first;
		  ++__first;
	
		  if (__pred(*__first))
		    return __first;
		  ++__first;
		}
	
	      switch (__last - __first)
		{
		case 3:
		  if (__pred(*__first))
		    return __first;
		  ++__first;
		case 2:
		  if (__pred(*__first))
		    return __first;
		  ++__first;
		case 1:
		  if (__pred(*__first))
		    return __first;
		  ++__first;
		case 0:
		default:
		  return __last;
		}
	    }
	
	  /// This is an overload used by find_if_not() for the Input Iterator case.
	  template<typename _InputIterator, typename _Predicate>
	    inline _InputIterator
	    __find_if_not(_InputIterator __first, _InputIterator __last,
			  _Predicate __pred, input_iterator_tag)
	    {
	      while (__first != __last && bool(__pred(*__first)))
		++__first;
	      return __first;
	    }
	
	  /// This is an overload used by find_if_not() for the RAI case.
	  template<typename _RandomAccessIterator, typename _Predicate>
	    _RandomAccessIterator
	    __find_if_not(_RandomAccessIterator __first, _RandomAccessIterator __last,
			  _Predicate __pred, random_access_iterator_tag)
	    {
	      typename iterator_traits<_RandomAccessIterator>::difference_type
		__trip_count = (__last - __first) >> 2;
	
	      for (; __trip_count > 0; --__trip_count)
		{
		  if (!bool(__pred(*__first)))
		    return __first;
		  ++__first;
	
		  if (!bool(__pred(*__first)))
		    return __first;
		  ++__first;
	
		  if (!bool(__pred(*__first)))
		    return __first;
		  ++__first;
	
		  if (!bool(__pred(*__first)))
		    return __first;
		  ++__first;
		}
	
	      switch (__last - __first)
		{
		case 3:
		  if (!bool(__pred(*__first)))
		    return __first;
		  ++__first;
		case 2:
		  if (!bool(__pred(*__first)))
		    return __first;
		  ++__first;
		case 1:
		  if (!bool(__pred(*__first)))
		    return __first;
		  ++__first;
		case 0:
		default:
		  return __last;
		}
	    }
	
	  /// Provided for stable_partition to use.
	  template<typename _InputIterator, typename _Predicate>
	    inline _InputIterator
	    __find_if_not(_InputIterator __first, _InputIterator __last,
			  _Predicate __pred)
	    {
	      return std::__find_if_not(__first, __last, __pred,
					std::__iterator_category(__first));
	    }
	
	  /// Like find_if_not(), but uses and updates a count of the
	  /// remaining range length instead of comparing against an end
	  /// iterator.
	  template<typename _InputIterator, typename _Predicate, typename _Distance>
	    _InputIterator
	    __find_if_not_n(_InputIterator __first, _Distance& __len, _Predicate __pred)
	    {
	      for (; __len; --__len, ++__first)
		if (!bool(__pred(*__first)))
		  break;
	      return __first;
	    }
	
	  // set_difference
	  // set_intersection
	  // set_symmetric_difference
	  // set_union
	  // for_each
	  // find
	  // find_if
	  // find_first_of
	  // adjacent_find
	  // count
	  // count_if
	  // search
	
	  /**
	   *  This is an uglified
	   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&)
	   *  overloaded for forward iterators.
	  */
	  template<typename _ForwardIterator, typename _Integer, typename _Tp>
	    _ForwardIterator
	    __search_n(_ForwardIterator __first, _ForwardIterator __last,
		       _Integer __count, const _Tp& __val,
		       std::forward_iterator_tag)
	    {
	      __first = _GLIBCXX_STD_A::find(__first, __last, __val);
	      while (__first != __last)
		{
		  typename iterator_traits<_ForwardIterator>::difference_type
		    __n = __count;
		  _ForwardIterator __i = __first;
		  ++__i;
		  while (__i != __last && __n != 1 && *__i == __val)
		    {
		      ++__i;
		      --__n;
		    }
		  if (__n == 1)
		    return __first;
		  if (__i == __last)
		    return __last;
		  __first = _GLIBCXX_STD_A::find(++__i, __last, __val);
		}
	      return __last;
	    }
	
	  /**
	   *  This is an uglified
	   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&)
	   *  overloaded for random access iterators.
	  */
	  template<typename _RandomAccessIter, typename _Integer, typename _Tp>
	    _RandomAccessIter
	    __search_n(_RandomAccessIter __first, _RandomAccessIter __last,
		       _Integer __count, const _Tp& __val, 
		       std::random_access_iterator_tag)
	    {
	      
	      typedef typename std::iterator_traits<_RandomAccessIter>::difference_type
		_DistanceType;
	
	      _DistanceType __tailSize = __last - __first;
	      _DistanceType __remainder = __count;
	
	      while (__remainder <= __tailSize) // the main loop...
		{
		  __first += __remainder;
		  __tailSize -= __remainder;
		  // __first here is always pointing to one past the last element of
		  // next possible match.
		  _RandomAccessIter __backTrack = __first; 
		  while (*--__backTrack == __val)
		    {
		      if (--__remainder == 0)
		        return (__first - __count); // Success
		    }
		  __remainder = __count + 1 - (__first - __backTrack);
		}
	      return __last; // Failure
	    }
	
	  // search_n
	
	  /**
	   *  This is an uglified
	   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&,
	   *	       _BinaryPredicate)
	   *  overloaded for forward iterators.
	  */
	  template<typename _ForwardIterator, typename _Integer, typename _Tp,
	           typename _BinaryPredicate>
	    _ForwardIterator
	    __search_n(_ForwardIterator __first, _ForwardIterator __last,
		       _Integer __count, const _Tp& __val,
		       _BinaryPredicate __binary_pred, std::forward_iterator_tag)
	    {
	      while (__first != __last && !bool(__binary_pred(*__first, __val)))
	        ++__first;
	
	      while (__first != __last)
		{
		  typename iterator_traits<_ForwardIterator>::difference_type
		    __n = __count;
		  _ForwardIterator __i = __first;
		  ++__i;
		  while (__i != __last && __n != 1 && bool(__binary_pred(*__i, __val)))
		    {
		      ++__i;
		      --__n;
		    }
		  if (__n == 1)
		    return __first;
		  if (__i == __last)
		    return __last;
		  __first = ++__i;
		  while (__first != __last
			 && !bool(__binary_pred(*__first, __val)))
		    ++__first;
		}
	      return __last;
	    }
	
	  /**
	   *  This is an uglified
	   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&,
	   *	       _BinaryPredicate)
	   *  overloaded for random access iterators.
	  */
	  template<typename _RandomAccessIter, typename _Integer, typename _Tp,
		   typename _BinaryPredicate>
	    _RandomAccessIter
	    __search_n(_RandomAccessIter __first, _RandomAccessIter __last,
		       _Integer __count, const _Tp& __val,
		       _BinaryPredicate __binary_pred, std::random_access_iterator_tag)
	    {
	      
	      typedef typename std::iterator_traits<_RandomAccessIter>::difference_type
		_DistanceType;
	
	      _DistanceType __tailSize = __last - __first;
	      _DistanceType __remainder = __count;
	
	      while (__remainder <= __tailSize) // the main loop...
		{
		  __first += __remainder;
		  __tailSize -= __remainder;
		  // __first here is always pointing to one past the last element of
		  // next possible match.
		  _RandomAccessIter __backTrack = __first; 
		  while (__binary_pred(*--__backTrack, __val))
		    {
		      if (--__remainder == 0)
		        return (__first - __count); // Success
		    }
		  __remainder = __count + 1 - (__first - __backTrack);
		}
	      return __last; // Failure
	    }
	
	  // find_end for forward iterators.
	  template<typename _ForwardIterator1, typename _ForwardIterator2>
	    _ForwardIterator1
	    __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		       _ForwardIterator2 __first2, _ForwardIterator2 __last2,
		       forward_iterator_tag, forward_iterator_tag)
	    {
	      if (__first2 == __last2)
		return __last1;
	      else
		{
		  _ForwardIterator1 __result = __last1;
		  while (1)
		    {
		      _ForwardIterator1 __new_result
			= _GLIBCXX_STD_A::search(__first1, __last1, __first2, __last2);
		      if (__new_result == __last1)
			return __result;
		      else
			{
			  __result = __new_result;
			  __first1 = __new_result;
			  ++__first1;
			}
		    }
		}
	    }
	
	  template<typename _ForwardIterator1, typename _ForwardIterator2,
		   typename _BinaryPredicate>
	    _ForwardIterator1
	    __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		       _ForwardIterator2 __first2, _ForwardIterator2 __last2,
		       forward_iterator_tag, forward_iterator_tag,
		       _BinaryPredicate __comp)
	    {
	      if (__first2 == __last2)
		return __last1;
	      else
		{
		  _ForwardIterator1 __result = __last1;
		  while (1)
		    {
		      _ForwardIterator1 __new_result
			= _GLIBCXX_STD_A::search(__first1, __last1, __first2,
						 __last2, __comp);
		      if (__new_result == __last1)
			return __result;
		      else
			{
			  __result = __new_result;
			  __first1 = __new_result;
			  ++__first1;
			}
		    }
		}
	    }
	
	  // find_end for bidirectional iterators (much faster).
	  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2>
	    _BidirectionalIterator1
	    __find_end(_BidirectionalIterator1 __first1,
		       _BidirectionalIterator1 __last1,
		       _BidirectionalIterator2 __first2,
		       _BidirectionalIterator2 __last2,
		       bidirectional_iterator_tag, bidirectional_iterator_tag)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_BidirectionalIteratorConcept<
					  _BidirectionalIterator1>)
	      __glibcxx_function_requires(_BidirectionalIteratorConcept<
					  _BidirectionalIterator2>)
	
	      typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1;
	      typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2;
	
	      _RevIterator1 __rlast1(__first1);
	      _RevIterator2 __rlast2(__first2);
	      _RevIterator1 __rresult = _GLIBCXX_STD_A::search(_RevIterator1(__last1),
							       __rlast1,
							       _RevIterator2(__last2),
							       __rlast2);
	
	      if (__rresult == __rlast1)
		return __last1;
	      else
		{
		  _BidirectionalIterator1 __result = __rresult.base();
		  std::advance(__result, -std::distance(__first2, __last2));
		  return __result;
		}
	    }
	
	  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
		   typename _BinaryPredicate>
	    _BidirectionalIterator1
	    __find_end(_BidirectionalIterator1 __first1,
		       _BidirectionalIterator1 __last1,
		       _BidirectionalIterator2 __first2,
		       _BidirectionalIterator2 __last2,
		       bidirectional_iterator_tag, bidirectional_iterator_tag,
		       _BinaryPredicate __comp)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_BidirectionalIteratorConcept<
					  _BidirectionalIterator1>)
	      __glibcxx_function_requires(_BidirectionalIteratorConcept<
					  _BidirectionalIterator2>)
	
	      typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1;
	      typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2;
	
	      _RevIterator1 __rlast1(__first1);
	      _RevIterator2 __rlast2(__first2);
	      _RevIterator1 __rresult = std::search(_RevIterator1(__last1), __rlast1,
						    _RevIterator2(__last2), __rlast2,
						    __comp);
	
	      if (__rresult == __rlast1)
		return __last1;
	      else
		{
		  _BidirectionalIterator1 __result = __rresult.base();
		  std::advance(__result, -std::distance(__first2, __last2));
		  return __result;
		}
	    }
	
	  /**
	   *  @brief  Find last matching subsequence in a sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first1  Start of range to search.
	   *  @param  __last1   End of range to search.
	   *  @param  __first2  Start of sequence to match.
	   *  @param  __last2   End of sequence to match.
	   *  @return   The last iterator @c i in the range
	   *  @p [__first1,__last1-(__last2-__first2)) such that @c *(i+N) ==
	   *  @p *(__first2+N) for each @c N in the range @p
	   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.
	   *
	   *  Searches the range @p [__first1,__last1) for a sub-sequence that
	   *  compares equal value-by-value with the sequence given by @p
	   *  [__first2,__last2) and returns an iterator to the __first
	   *  element of the sub-sequence, or @p __last1 if the sub-sequence
	   *  is not found.  The sub-sequence will be the last such
	   *  subsequence contained in [__first,__last1).
	   *
	   *  Because the sub-sequence must lie completely within the range @p
	   *  [__first1,__last1) it must start at a position less than @p
	   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
	   *  length of the sub-sequence.  This means that the returned
	   *  iterator @c i will be in the range @p
	   *  [__first1,__last1-(__last2-__first2))
	  */
	  template<typename _ForwardIterator1, typename _ForwardIterator2>
	    inline _ForwardIterator1
	    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		     _ForwardIterator2 __first2, _ForwardIterator2 __last2)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
	      __glibcxx_function_requires(_EqualOpConcept<
		    typename iterator_traits<_ForwardIterator1>::value_type,
		    typename iterator_traits<_ForwardIterator2>::value_type>)
	      __glibcxx_requires_valid_range(__first1, __last1);
	      __glibcxx_requires_valid_range(__first2, __last2);
	
	      return std::__find_end(__first1, __last1, __first2, __last2,
				     std::__iterator_category(__first1),
				     std::__iterator_category(__first2));
	    }
	
	  /**
	   *  @brief  Find last matching subsequence in a sequence using a predicate.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first1  Start of range to search.
	   *  @param  __last1   End of range to search.
	   *  @param  __first2  Start of sequence to match.
	   *  @param  __last2   End of sequence to match.
	   *  @param  __comp    The predicate to use.
	   *  @return The last iterator @c i in the range @p
	   *  [__first1,__last1-(__last2-__first2)) such that @c
	   *  predicate(*(i+N), @p (__first2+N)) is true for each @c N in the
	   *  range @p [0,__last2-__first2), or @p __last1 if no such iterator
	   *  exists.
	   *
	   *  Searches the range @p [__first1,__last1) for a sub-sequence that
	   *  compares equal value-by-value with the sequence given by @p
	   *  [__first2,__last2) using comp as a predicate and returns an
	   *  iterator to the first element of the sub-sequence, or @p __last1
	   *  if the sub-sequence is not found.  The sub-sequence will be the
	   *  last such subsequence contained in [__first,__last1).
	   *
	   *  Because the sub-sequence must lie completely within the range @p
	   *  [__first1,__last1) it must start at a position less than @p
	   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
	   *  length of the sub-sequence.  This means that the returned
	   *  iterator @c i will be in the range @p
	   *  [__first1,__last1-(__last2-__first2))
	  */
	  template<typename _ForwardIterator1, typename _ForwardIterator2,
		   typename _BinaryPredicate>
	    inline _ForwardIterator1
	    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
		     _BinaryPredicate __comp)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
		    typename iterator_traits<_ForwardIterator1>::value_type,
		    typename iterator_traits<_ForwardIterator2>::value_type>)
	      __glibcxx_requires_valid_range(__first1, __last1);
	      __glibcxx_requires_valid_range(__first2, __last2);
	
	      return std::__find_end(__first1, __last1, __first2, __last2,
				     std::__iterator_category(__first1),
				     std::__iterator_category(__first2),
				     __comp);
	    }
	
	#if __cplusplus >= 201103L
	  /**
	   *  @brief  Checks that a predicate is true for all the elements
	   *          of a sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first   An input iterator.
	   *  @param  __last    An input iterator.
	   *  @param  __pred    A predicate.
	   *  @return  True if the check is true, false otherwise.
	   *
	   *  Returns true if @p __pred is true for each element in the range
	   *  @p [__first,__last), and false otherwise.
	  */
	  template<typename _InputIterator, typename _Predicate>
	    inline bool
	    all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
	    { return __last == std::find_if_not(__first, __last, __pred); }
	
	  /**
	   *  @brief  Checks that a predicate is false for all the elements
	   *          of a sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first   An input iterator.
	   *  @param  __last    An input iterator.
	   *  @param  __pred    A predicate.
	   *  @return  True if the check is true, false otherwise.
	   *
	   *  Returns true if @p __pred is false for each element in the range
	   *  @p [__first,__last), and false otherwise.
	  */
	  template<typename _InputIterator, typename _Predicate>
	    inline bool
	    none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
	    { return __last == _GLIBCXX_STD_A::find_if(__first, __last, __pred); }
	
	  /**
	   *  @brief  Checks that a predicate is false for at least an element
	   *          of a sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first   An input iterator.
	   *  @param  __last    An input iterator.
	   *  @param  __pred    A predicate.
	   *  @return  True if the check is true, false otherwise.
	   *
	   *  Returns true if an element exists in the range @p
	   *  [__first,__last) such that @p __pred is true, and false
	   *  otherwise.
	  */
	  template<typename _InputIterator, typename _Predicate>
	    inline bool
	    any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
	    { return !std::none_of(__first, __last, __pred); }
	
	  /**
	   *  @brief  Find the first element in a sequence for which a
	   *          predicate is false.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first  An input iterator.
	   *  @param  __last   An input iterator.
	   *  @param  __pred   A predicate.
	   *  @return   The first iterator @c i in the range @p [__first,__last)
	   *  such that @p __pred(*i) is false, or @p __last if no such iterator exists.
	  */
	  template<typename _InputIterator, typename _Predicate>
	    inline _InputIterator
	    find_if_not(_InputIterator __first, _InputIterator __last,
			_Predicate __pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		      typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	      return std::__find_if_not(__first, __last, __pred);
	    }
	
	  /**
	   *  @brief  Checks whether the sequence is partitioned.
	   *  @ingroup mutating_algorithms
	   *  @param  __first  An input iterator.
	   *  @param  __last   An input iterator.
	   *  @param  __pred   A predicate.
	   *  @return  True if the range @p [__first,__last) is partioned by @p __pred,
	   *  i.e. if all elements that satisfy @p __pred appear before those that
	   *  do not.
	  */
	  template<typename _InputIterator, typename _Predicate>
	    inline bool
	    is_partitioned(_InputIterator __first, _InputIterator __last,
			   _Predicate __pred)
	    {
	      __first = std::find_if_not(__first, __last, __pred);
	      return std::none_of(__first, __last, __pred);
	    }
	
	  /**
	   *  @brief  Find the partition point of a partitioned range.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __pred    A predicate.
	   *  @return  An iterator @p mid such that @p all_of(__first, mid, __pred)
	   *           and @p none_of(mid, __last, __pred) are both true.
	  */
	  template<typename _ForwardIterator, typename _Predicate>
	    _ForwardIterator
	    partition_point(_ForwardIterator __first, _ForwardIterator __last,
			    _Predicate __pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		      typename iterator_traits<_ForwardIterator>::value_type>)
	
	      // A specific debug-mode test will be necessary...
	      __glibcxx_requires_valid_range(__first, __last);
	
	      typedef typename iterator_traits<_ForwardIterator>::difference_type
		_DistanceType;
	
	      _DistanceType __len = std::distance(__first, __last);
	      _DistanceType __half;
	      _ForwardIterator __middle;
	
	      while (__len > 0)
		{
		  __half = __len >> 1;
		  __middle = __first;
		  std::advance(__middle, __half);
		  if (__pred(*__middle))
		    {
		      __first = __middle;
		      ++__first;
		      __len = __len - __half - 1;
		    }
		  else
		    __len = __half;
		}
	      return __first;
	    }
	#endif
	
	
	  /**
	   *  @brief Copy a sequence, removing elements of a given value.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   An input iterator.
	   *  @param  __last    An input iterator.
	   *  @param  __result  An output iterator.
	   *  @param  __value   The value to be removed.
	   *  @return   An iterator designating the end of the resulting sequence.
	   *
	   *  Copies each element in the range @p [__first,__last) not equal
	   *  to @p __value to the range beginning at @p __result.
	   *  remove_copy() is stable, so the relative order of elements that
	   *  are copied is unchanged.
	  */
	  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
	    _OutputIterator
	    remove_copy(_InputIterator __first, _InputIterator __last,
			_OutputIterator __result, const _Tp& __value)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_function_requires(_EqualOpConcept<
		    typename iterator_traits<_InputIterator>::value_type, _Tp>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      for (; __first != __last; ++__first)
		if (!(*__first == __value))
		  {
		    *__result = *__first;
		    ++__result;
		  }
	      return __result;
	    }
	
	  /**
	   *  @brief Copy a sequence, removing elements for which a predicate is true.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   An input iterator.
	   *  @param  __last    An input iterator.
	   *  @param  __result  An output iterator.
	   *  @param  __pred    A predicate.
	   *  @return   An iterator designating the end of the resulting sequence.
	   *
	   *  Copies each element in the range @p [__first,__last) for which
	   *  @p __pred returns false to the range beginning at @p __result.
	   *
	   *  remove_copy_if() is stable, so the relative order of elements that are
	   *  copied is unchanged.
	  */
	  template<typename _InputIterator, typename _OutputIterator,
		   typename _Predicate>
	    _OutputIterator
	    remove_copy_if(_InputIterator __first, _InputIterator __last,
			   _OutputIterator __result, _Predicate __pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      for (; __first != __last; ++__first)
		if (!bool(__pred(*__first)))
		  {
		    *__result = *__first;
		    ++__result;
		  }
	      return __result;
	    }
	
	#if __cplusplus >= 201103L
	  /**
	   *  @brief Copy the elements of a sequence for which a predicate is true.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   An input iterator.
	   *  @param  __last    An input iterator.
	   *  @param  __result  An output iterator.
	   *  @param  __pred    A predicate.
	   *  @return   An iterator designating the end of the resulting sequence.
	   *
	   *  Copies each element in the range @p [__first,__last) for which
	   *  @p __pred returns true to the range beginning at @p __result.
	   *
	   *  copy_if() is stable, so the relative order of elements that are
	   *  copied is unchanged.
	  */
	  template<typename _InputIterator, typename _OutputIterator,
		   typename _Predicate>
	    _OutputIterator
	    copy_if(_InputIterator __first, _InputIterator __last,
		    _OutputIterator __result, _Predicate __pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      for (; __first != __last; ++__first)
		if (__pred(*__first))
		  {
		    *__result = *__first;
		    ++__result;
		  }
	      return __result;
	    }
	
	
	  template<typename _InputIterator, typename _Size, typename _OutputIterator>
	    _OutputIterator
	    __copy_n(_InputIterator __first, _Size __n,
		     _OutputIterator __result, input_iterator_tag)
	    {
	      if (__n > 0)
		{
		  while (true)
		    {
		      *__result = *__first;
		      ++__result;
		      if (--__n > 0)
			++__first;
		      else
			break;
		    }
		}
	      return __result;
	    }
	
	  template<typename _RandomAccessIterator, typename _Size,
		   typename _OutputIterator>
	    inline _OutputIterator
	    __copy_n(_RandomAccessIterator __first, _Size __n,
		     _OutputIterator __result, random_access_iterator_tag)
	    { return std::copy(__first, __first + __n, __result); }
	
	  /**
	   *  @brief Copies the range [first,first+n) into [result,result+n).
	   *  @ingroup mutating_algorithms
	   *  @param  __first  An input iterator.
	   *  @param  __n      The number of elements to copy.
	   *  @param  __result An output iterator.
	   *  @return  result+n.
	   *
	   *  This inline function will boil down to a call to @c memmove whenever
	   *  possible.  Failing that, if random access iterators are passed, then the
	   *  loop count will be known (and therefore a candidate for compiler
	   *  optimizations such as unrolling).
	  */
	  template<typename _InputIterator, typename _Size, typename _OutputIterator>
	    inline _OutputIterator
	    copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		    typename iterator_traits<_InputIterator>::value_type>)
	
	      return std::__copy_n(__first, __n, __result,
				   std::__iterator_category(__first));
	    }
	
	  /**
	   *  @brief Copy the elements of a sequence to separate output sequences
	   *         depending on the truth value of a predicate.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   An input iterator.
	   *  @param  __last    An input iterator.
	   *  @param  __out_true   An output iterator.
	   *  @param  __out_false  An output iterator.
	   *  @param  __pred    A predicate.
	   *  @return   A pair designating the ends of the resulting sequences.
	   *
	   *  Copies each element in the range @p [__first,__last) for which
	   *  @p __pred returns true to the range beginning at @p out_true
	   *  and each element for which @p __pred returns false to @p __out_false.
	  */
	  template<typename _InputIterator, typename _OutputIterator1,
		   typename _OutputIterator2, typename _Predicate>
	    pair<_OutputIterator1, _OutputIterator2>
	    partition_copy(_InputIterator __first, _InputIterator __last,
			   _OutputIterator1 __out_true, _OutputIterator2 __out_false,
			   _Predicate __pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator1,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator2,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	      
	      for (; __first != __last; ++__first)
		if (__pred(*__first))
		  {
		    *__out_true = *__first;
		    ++__out_true;
		  }
		else
		  {
		    *__out_false = *__first;
		    ++__out_false;
		  }
	
	      return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
	    }
	#endif
	
	  /**
	   *  @brief Remove elements from a sequence.
	   *  @ingroup mutating_algorithms
	   *  @param  __first  An input iterator.
	   *  @param  __last   An input iterator.
	   *  @param  __value  The value to be removed.
	   *  @return   An iterator designating the end of the resulting sequence.
	   *
	   *  All elements equal to @p __value are removed from the range
	   *  @p [__first,__last).
	   *
	   *  remove() is stable, so the relative order of elements that are
	   *  not removed is unchanged.
	   *
	   *  Elements between the end of the resulting sequence and @p __last
	   *  are still present, but their value is unspecified.
	  */
	  template<typename _ForwardIterator, typename _Tp>
	    _ForwardIterator
	    remove(_ForwardIterator __first, _ForwardIterator __last,
		   const _Tp& __value)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
					  _ForwardIterator>)
	      __glibcxx_function_requires(_EqualOpConcept<
		    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      __first = _GLIBCXX_STD_A::find(__first, __last, __value);
	      if(__first == __last)
	        return __first;
	      _ForwardIterator __result = __first;
	      ++__first;
	      for(; __first != __last; ++__first)
	        if(!(*__first == __value))
	          {
	            *__result = _GLIBCXX_MOVE(*__first);
	            ++__result;
	          }
	      return __result;
	    }
	
	  /**
	   *  @brief Remove elements from a sequence using a predicate.
	   *  @ingroup mutating_algorithms
	   *  @param  __first  A forward iterator.
	   *  @param  __last   A forward iterator.
	   *  @param  __pred   A predicate.
	   *  @return   An iterator designating the end of the resulting sequence.
	   *
	   *  All elements for which @p __pred returns true are removed from the range
	   *  @p [__first,__last).
	   *
	   *  remove_if() is stable, so the relative order of elements that are
	   *  not removed is unchanged.
	   *
	   *  Elements between the end of the resulting sequence and @p __last
	   *  are still present, but their value is unspecified.
	  */
	  template<typename _ForwardIterator, typename _Predicate>
	    _ForwardIterator
	    remove_if(_ForwardIterator __first, _ForwardIterator __last,
		      _Predicate __pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
					  _ForwardIterator>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      __first = _GLIBCXX_STD_A::find_if(__first, __last, __pred);
	      if(__first == __last)
	        return __first;
	      _ForwardIterator __result = __first;
	      ++__first;
	      for(; __first != __last; ++__first)
	        if(!bool(__pred(*__first)))
	          {
	            *__result = _GLIBCXX_MOVE(*__first);
	            ++__result;
	          }
	      return __result;
	    }
	
	  /**
	   *  @brief Remove consecutive duplicate values from a sequence.
	   *  @ingroup mutating_algorithms
	   *  @param  __first  A forward iterator.
	   *  @param  __last   A forward iterator.
	   *  @return  An iterator designating the end of the resulting sequence.
	   *
	   *  Removes all but the first element from each group of consecutive
	   *  values that compare equal.
	   *  unique() is stable, so the relative order of elements that are
	   *  not removed is unchanged.
	   *  Elements between the end of the resulting sequence and @p __last
	   *  are still present, but their value is unspecified.
	  */
	  template<typename _ForwardIterator>
	    _ForwardIterator
	    unique(_ForwardIterator __first, _ForwardIterator __last)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
					  _ForwardIterator>)
	      __glibcxx_function_requires(_EqualityComparableConcept<
			     typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      // Skip the beginning, if already unique.
	      __first = _GLIBCXX_STD_A::adjacent_find(__first, __last);
	      if (__first == __last)
		return __last;
	
	      // Do the real copy work.
	      _ForwardIterator __dest = __first;
	      ++__first;
	      while (++__first != __last)
		if (!(*__dest == *__first))
		  *++__dest = _GLIBCXX_MOVE(*__first);
	      return ++__dest;
	    }
	
	  /**
	   *  @brief Remove consecutive values from a sequence using a predicate.
	   *  @ingroup mutating_algorithms
	   *  @param  __first        A forward iterator.
	   *  @param  __last         A forward iterator.
	   *  @param  __binary_pred  A binary predicate.
	   *  @return  An iterator designating the end of the resulting sequence.
	   *
	   *  Removes all but the first element from each group of consecutive
	   *  values for which @p __binary_pred returns true.
	   *  unique() is stable, so the relative order of elements that are
	   *  not removed is unchanged.
	   *  Elements between the end of the resulting sequence and @p __last
	   *  are still present, but their value is unspecified.
	  */
	  template<typename _ForwardIterator, typename _BinaryPredicate>
	    _ForwardIterator
	    unique(_ForwardIterator __first, _ForwardIterator __last,
	           _BinaryPredicate __binary_pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
					  _ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
			typename iterator_traits<_ForwardIterator>::value_type,
			typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      // Skip the beginning, if already unique.
	      __first = _GLIBCXX_STD_A::adjacent_find(__first, __last, __binary_pred);
	      if (__first == __last)
		return __last;
	
	      // Do the real copy work.
	      _ForwardIterator __dest = __first;
	      ++__first;
	      while (++__first != __last)
		if (!bool(__binary_pred(*__dest, *__first)))
		  *++__dest = _GLIBCXX_MOVE(*__first);
	      return ++__dest;
	    }
	
	  /**
	   *  This is an uglified unique_copy(_InputIterator, _InputIterator,
	   *                                  _OutputIterator)
	   *  overloaded for forward iterators and output iterator as result.
	  */
	  template<typename _ForwardIterator, typename _OutputIterator>
	    _OutputIterator
	    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,
			  _OutputIterator __result,
			  forward_iterator_tag, output_iterator_tag)
	    {
	      // concept requirements -- taken care of in dispatching function
	      _ForwardIterator __next = __first;
	      *__result = *__first;
	      while (++__next != __last)
		if (!(*__first == *__next))
		  {
		    __first = __next;
		    *++__result = *__first;
		  }
	      return ++__result;
	    }
	
	  /**
	   *  This is an uglified unique_copy(_InputIterator, _InputIterator,
	   *                                  _OutputIterator)
	   *  overloaded for input iterators and output iterator as result.
	  */
	  template<typename _InputIterator, typename _OutputIterator>
	    _OutputIterator
	    __unique_copy(_InputIterator __first, _InputIterator __last,
			  _OutputIterator __result,
			  input_iterator_tag, output_iterator_tag)
	    {
	      // concept requirements -- taken care of in dispatching function
	      typename iterator_traits<_InputIterator>::value_type __value = *__first;
	      *__result = __value;
	      while (++__first != __last)
		if (!(__value == *__first))
		  {
		    __value = *__first;
		    *++__result = __value;
		  }
	      return ++__result;
	    }
	
	  /**
	   *  This is an uglified unique_copy(_InputIterator, _InputIterator,
	   *                                  _OutputIterator)
	   *  overloaded for input iterators and forward iterator as result.
	  */
	  template<typename _InputIterator, typename _ForwardIterator>
	    _ForwardIterator
	    __unique_copy(_InputIterator __first, _InputIterator __last,
			  _ForwardIterator __result,
			  input_iterator_tag, forward_iterator_tag)
	    {
	      // concept requirements -- taken care of in dispatching function
	      *__result = *__first;
	      while (++__first != __last)
		if (!(*__result == *__first))
		  *++__result = *__first;
	      return ++__result;
	    }
	
	  /**
	   *  This is an uglified
	   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
	   *              _BinaryPredicate)
	   *  overloaded for forward iterators and output iterator as result.
	  */
	  template<typename _ForwardIterator, typename _OutputIterator,
		   typename _BinaryPredicate>
	    _OutputIterator
	    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,
			  _OutputIterator __result, _BinaryPredicate __binary_pred,
			  forward_iterator_tag, output_iterator_tag)
	    {
	      // concept requirements -- iterators already checked
	      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
		  typename iterator_traits<_ForwardIterator>::value_type,
		  typename iterator_traits<_ForwardIterator>::value_type>)
	
	      _ForwardIterator __next = __first;
	      *__result = *__first;
	      while (++__next != __last)
		if (!bool(__binary_pred(*__first, *__next)))
		  {
		    __first = __next;
		    *++__result = *__first;
		  }
	      return ++__result;
	    }
	
	  /**
	   *  This is an uglified
	   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
	   *              _BinaryPredicate)
	   *  overloaded for input iterators and output iterator as result.
	  */
	  template<typename _InputIterator, typename _OutputIterator,
		   typename _BinaryPredicate>
	    _OutputIterator
	    __unique_copy(_InputIterator __first, _InputIterator __last,
			  _OutputIterator __result, _BinaryPredicate __binary_pred,
			  input_iterator_tag, output_iterator_tag)
	    {
	      // concept requirements -- iterators already checked
	      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
		  typename iterator_traits<_InputIterator>::value_type,
		  typename iterator_traits<_InputIterator>::value_type>)
	
	      typename iterator_traits<_InputIterator>::value_type __value = *__first;
	      *__result = __value;
	      while (++__first != __last)
		if (!bool(__binary_pred(__value, *__first)))
		  {
		    __value = *__first;
		    *++__result = __value;
		  }
	      return ++__result;
	    }
	
	  /**
	   *  This is an uglified
	   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,
	   *              _BinaryPredicate)
	   *  overloaded for input iterators and forward iterator as result.
	  */
	  template<typename _InputIterator, typename _ForwardIterator,
		   typename _BinaryPredicate>
	    _ForwardIterator
	    __unique_copy(_InputIterator __first, _InputIterator __last,
			  _ForwardIterator __result, _BinaryPredicate __binary_pred,
			  input_iterator_tag, forward_iterator_tag)
	    {
	      // concept requirements -- iterators already checked
	      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
		  typename iterator_traits<_ForwardIterator>::value_type,
		  typename iterator_traits<_InputIterator>::value_type>)
	
	      *__result = *__first;
	      while (++__first != __last)
		if (!bool(__binary_pred(*__result, *__first)))
		  *++__result = *__first;
	      return ++__result;
	    }
	
	  /**
	   *  This is an uglified reverse(_BidirectionalIterator,
	   *                              _BidirectionalIterator)
	   *  overloaded for bidirectional iterators.
	  */
	  template<typename _BidirectionalIterator>
	    void
	    __reverse(_BidirectionalIterator __first, _BidirectionalIterator __last,
		      bidirectional_iterator_tag)
	    {
	      while (true)
		if (__first == __last || __first == --__last)
		  return;
		else
		  {
		    std::iter_swap(__first, __last);
		    ++__first;
		  }
	    }
	
	  /**
	   *  This is an uglified reverse(_BidirectionalIterator,
	   *                              _BidirectionalIterator)
	   *  overloaded for random access iterators.
	  */
	  template<typename _RandomAccessIterator>
	    void
	    __reverse(_RandomAccessIterator __first, _RandomAccessIterator __last,
		      random_access_iterator_tag)
	    {
	      if (__first == __last)
		return;
	      --__last;
	      while (__first < __last)
		{
		  std::iter_swap(__first, __last);
		  ++__first;
		  --__last;
		}
	    }
	
	  /**
	   *  @brief Reverse a sequence.
	   *  @ingroup mutating_algorithms
	   *  @param  __first  A bidirectional iterator.
	   *  @param  __last   A bidirectional iterator.
	   *  @return   reverse() returns no value.
	   *
	   *  Reverses the order of the elements in the range @p [__first,__last),
	   *  so that the first element becomes the last etc.
	   *  For every @c i such that @p 0<=i<=(__last-__first)/2), @p reverse()
	   *  swaps @p *(__first+i) and @p *(__last-(i+1))
	  */
	  template<typename _BidirectionalIterator>
	    inline void
	    reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
					  _BidirectionalIterator>)
	      __glibcxx_requires_valid_range(__first, __last);
	      std::__reverse(__first, __last, std::__iterator_category(__first));
	    }
	
	  /**
	   *  @brief Copy a sequence, reversing its elements.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   A bidirectional iterator.
	   *  @param  __last    A bidirectional iterator.
	   *  @param  __result  An output iterator.
	   *  @return  An iterator designating the end of the resulting sequence.
	   *
	   *  Copies the elements in the range @p [__first,__last) to the
	   *  range @p [__result,__result+(__last-__first)) such that the
	   *  order of the elements is reversed.  For every @c i such that @p
	   *  0<=i<=(__last-__first), @p reverse_copy() performs the
	   *  assignment @p *(__result+(__last-__first)-1-i) = *(__first+i).
	   *  The ranges @p [__first,__last) and @p
	   *  [__result,__result+(__last-__first)) must not overlap.
	  */
	  template<typename _BidirectionalIterator, typename _OutputIterator>
	    _OutputIterator
	    reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last,
			 _OutputIterator __result)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_BidirectionalIteratorConcept<
					  _BidirectionalIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
			typename iterator_traits<_BidirectionalIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      while (__first != __last)
		{
		  --__last;
		  *__result = *__last;
		  ++__result;
		}
	      return __result;
	    }
	
	  /**
	   *  This is a helper function for the rotate algorithm specialized on RAIs.
	   *  It returns the greatest common divisor of two integer values.
	  */
	  template<typename _EuclideanRingElement>
	    _EuclideanRingElement
	    __gcd(_EuclideanRingElement __m, _EuclideanRingElement __n)
	    {
	      while (__n != 0)
		{
		  _EuclideanRingElement __t = __m % __n;
		  __m = __n;
		  __n = __t;
		}
	      return __m;
	    }
	
	  /// This is a helper function for the rotate algorithm.
	  template<typename _ForwardIterator>
	    void
	    __rotate(_ForwardIterator __first,
		     _ForwardIterator __middle,
		     _ForwardIterator __last,
		     forward_iterator_tag)
	    {
	      if (__first == __middle || __last  == __middle)
		return;
	
	      _ForwardIterator __first2 = __middle;
	      do
		{
		  std::iter_swap(__first, __first2);
		  ++__first;
		  ++__first2;
		  if (__first == __middle)
		    __middle = __first2;
		}
	      while (__first2 != __last);
	
	      __first2 = __middle;
	
	      while (__first2 != __last)
		{
		  std::iter_swap(__first, __first2);
		  ++__first;
		  ++__first2;
		  if (__first == __middle)
		    __middle = __first2;
		  else if (__first2 == __last)
		    __first2 = __middle;
		}
	    }
	
	   /// This is a helper function for the rotate algorithm.
	  template<typename _BidirectionalIterator>
	    void
	    __rotate(_BidirectionalIterator __first,
		     _BidirectionalIterator __middle,
		     _BidirectionalIterator __last,
		      bidirectional_iterator_tag)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
					  _BidirectionalIterator>)
	
	      if (__first == __middle || __last  == __middle)
		return;
	
	      std::__reverse(__first,  __middle, bidirectional_iterator_tag());
	      std::__reverse(__middle, __last,   bidirectional_iterator_tag());
	
	      while (__first != __middle && __middle != __last)
		{
		  std::iter_swap(__first, --__last);
		  ++__first;
		}
	
	      if (__first == __middle)
		std::__reverse(__middle, __last,   bidirectional_iterator_tag());
	      else
		std::__reverse(__first,  __middle, bidirectional_iterator_tag());
	    }
	
	  /// This is a helper function for the rotate algorithm.
	  template<typename _RandomAccessIterator>
	    void
	    __rotate(_RandomAccessIterator __first,
		     _RandomAccessIterator __middle,
		     _RandomAccessIterator __last,
		     random_access_iterator_tag)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
					  _RandomAccessIterator>)
	
	      if (__first == __middle || __last  == __middle)
		return;
	
	      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
		_Distance;
	      typedef typename iterator_traits<_RandomAccessIterator>::value_type
		_ValueType;
	
	      _Distance __n = __last   - __first;
	      _Distance __k = __middle - __first;
	
	      if (__k == __n - __k)
		{
		  std::swap_ranges(__first, __middle, __middle);
		  return;
		}
	
	      _RandomAccessIterator __p = __first;
	
	      for (;;)
		{
		  if (__k < __n - __k)
		    {
		      if (__is_pod(_ValueType) && __k == 1)
			{
			  _ValueType __t = _GLIBCXX_MOVE(*__p);
			  _GLIBCXX_MOVE3(__p + 1, __p + __n, __p);
			  *(__p + __n - 1) = _GLIBCXX_MOVE(__t);
			  return;
			}
		      _RandomAccessIterator __q = __p + __k;
		      for (_Distance __i = 0; __i < __n - __k; ++ __i)
			{
			  std::iter_swap(__p, __q);
			  ++__p;
			  ++__q;
			}
		      __n %= __k;
		      if (__n == 0)
			return;
		      std::swap(__n, __k);
		      __k = __n - __k;
		    }
		  else
		    {
		      __k = __n - __k;
		      if (__is_pod(_ValueType) && __k == 1)
			{
			  _ValueType __t = _GLIBCXX_MOVE(*(__p + __n - 1));
			  _GLIBCXX_MOVE_BACKWARD3(__p, __p + __n - 1, __p + __n);
			  *__p = _GLIBCXX_MOVE(__t);
			  return;
			}
		      _RandomAccessIterator __q = __p + __n;
		      __p = __q - __k;
		      for (_Distance __i = 0; __i < __n - __k; ++ __i)
			{
			  --__p;
			  --__q;
			  std::iter_swap(__p, __q);
			}
		      __n %= __k;
		      if (__n == 0)
			return;
		      std::swap(__n, __k);
		    }
		}
	    }
	
	  /**
	   *  @brief Rotate the elements of a sequence.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   A forward iterator.
	   *  @param  __middle  A forward iterator.
	   *  @param  __last    A forward iterator.
	   *  @return  Nothing.
	   *
	   *  Rotates the elements of the range @p [__first,__last) by 
	   *  @p (__middle - __first) positions so that the element at @p __middle
	   *  is moved to @p __first, the element at @p __middle+1 is moved to
	   *  @p __first+1 and so on for each element in the range
	   *  @p [__first,__last).
	   *
	   *  This effectively swaps the ranges @p [__first,__middle) and
	   *  @p [__middle,__last).
	   *
	   *  Performs
	   *   @p *(__first+(n+(__last-__middle))%(__last-__first))=*(__first+n)
	   *  for each @p n in the range @p [0,__last-__first).
	  */
	  template<typename _ForwardIterator>
	    inline void
	    rotate(_ForwardIterator __first, _ForwardIterator __middle,
		   _ForwardIterator __last)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
					  _ForwardIterator>)
	      __glibcxx_requires_valid_range(__first, __middle);
	      __glibcxx_requires_valid_range(__middle, __last);
	
	      typedef typename iterator_traits<_ForwardIterator>::iterator_category
		_IterType;
	      std::__rotate(__first, __middle, __last, _IterType());
	    }
	
	  /**
	   *  @brief Copy a sequence, rotating its elements.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   A forward iterator.
	   *  @param  __middle  A forward iterator.
	   *  @param  __last    A forward iterator.
	   *  @param  __result  An output iterator.
	   *  @return   An iterator designating the end of the resulting sequence.
	   *
	   *  Copies the elements of the range @p [__first,__last) to the
	   *  range beginning at @result, rotating the copied elements by 
	   *  @p (__middle-__first) positions so that the element at @p __middle
	   *  is moved to @p __result, the element at @p __middle+1 is moved
	   *  to @p __result+1 and so on for each element in the range @p
	   *  [__first,__last).
	   *
	   *  Performs 
	   *  @p *(__result+(n+(__last-__middle))%(__last-__first))=*(__first+n)
	   *  for each @p n in the range @p [0,__last-__first).
	  */
	  template<typename _ForwardIterator, typename _OutputIterator>
	    _OutputIterator
	    rotate_copy(_ForwardIterator __first, _ForwardIterator __middle,
	                _ForwardIterator __last, _OutputIterator __result)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
			typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __middle);
	      __glibcxx_requires_valid_range(__middle, __last);
	
	      return std::copy(__first, __middle,
	                       std::copy(__middle, __last, __result));
	    }
	
	  /// This is a helper function...
	  template<typename _ForwardIterator, typename _Predicate>
	    _ForwardIterator
	    __partition(_ForwardIterator __first, _ForwardIterator __last,
			_Predicate __pred, forward_iterator_tag)
	    {
	      if (__first == __last)
		return __first;
	
	      while (__pred(*__first))
		if (++__first == __last)
		  return __first;
	
	      _ForwardIterator __next = __first;
	
	      while (++__next != __last)
		if (__pred(*__next))
		  {
		    std::iter_swap(__first, __next);
		    ++__first;
		  }
	
	      return __first;
	    }
	
	  /// This is a helper function...
	  template<typename _BidirectionalIterator, typename _Predicate>
	    _BidirectionalIterator
	    __partition(_BidirectionalIterator __first, _BidirectionalIterator __last,
			_Predicate __pred, bidirectional_iterator_tag)
	    {
	      while (true)
		{
		  while (true)
		    if (__first == __last)
		      return __first;
		    else if (__pred(*__first))
		      ++__first;
		    else
		      break;
		  --__last;
		  while (true)
		    if (__first == __last)
		      return __first;
		    else if (!bool(__pred(*__last)))
		      --__last;
		    else
		      break;
		  std::iter_swap(__first, __last);
		  ++__first;
		}
	    }
	
	  // partition
	
	  /// This is a helper function...
	  /// Requires __len != 0 and !__pred(*__first),
	  /// same as __stable_partition_adaptive.
	  template<typename _ForwardIterator, typename _Predicate, typename _Distance>
	    _ForwardIterator
	    __inplace_stable_partition(_ForwardIterator __first,
				       _Predicate __pred, _Distance __len)
	    {
	      if (__len == 1)
		return __first;
	      _ForwardIterator __middle = __first;
	      std::advance(__middle, __len / 2);
	      _ForwardIterator __left_split =
		std::__inplace_stable_partition(__first, __pred, __len / 2);
	      // Advance past true-predicate values to satisfy this
	      // function's preconditions.
	      _Distance __right_len = __len - __len / 2;
	      _ForwardIterator __right_split =
		std::__find_if_not_n(__middle, __right_len, __pred);
	      if (__right_len)
		__right_split = std::__inplace_stable_partition(__middle,
								__pred,
								__right_len);
	      std::rotate(__left_split, __middle, __right_split);
	      std::advance(__left_split, std::distance(__middle, __right_split));
	      return __left_split;
	    }
	
	  /// This is a helper function...
	  /// Requires __first != __last and !__pred(*__first)
	  /// and __len == distance(__first, __last).
	  ///
	  /// !__pred(*__first) allows us to guarantee that we don't
	  /// move-assign an element onto itself.
	  template<typename _ForwardIterator, typename _Pointer, typename _Predicate,
		   typename _Distance>
	    _ForwardIterator
	    __stable_partition_adaptive(_ForwardIterator __first,
					_ForwardIterator __last,
					_Predicate __pred, _Distance __len,
					_Pointer __buffer,
					_Distance __buffer_size)
	    {
	      if (__len <= __buffer_size)
		{
		  _ForwardIterator __result1 = __first;
		  _Pointer __result2 = __buffer;
		  // The precondition guarantees that !__pred(*__first), so
		  // move that element to the buffer before starting the loop.
		  // This ensures that we only call __pred once per element.
		  *__result2 = _GLIBCXX_MOVE(*__first);
		  ++__result2;
		  ++__first;
		  for (; __first != __last; ++__first)
		    if (__pred(*__first))
		      {
			*__result1 = _GLIBCXX_MOVE(*__first);
			++__result1;
		      }
		    else
		      {
			*__result2 = _GLIBCXX_MOVE(*__first);
			++__result2;
		      }
		  _GLIBCXX_MOVE3(__buffer, __result2, __result1);
		  return __result1;
		}
	      else
		{
		  _ForwardIterator __middle = __first;
		  std::advance(__middle, __len / 2);
		  _ForwardIterator __left_split =
		    std::__stable_partition_adaptive(__first, __middle, __pred,
						     __len / 2, __buffer,
						     __buffer_size);
		  // Advance past true-predicate values to satisfy this
		  // function's preconditions.
		  _Distance __right_len = __len - __len / 2;
		  _ForwardIterator __right_split =
		    std::__find_if_not_n(__middle, __right_len, __pred);
		  if (__right_len)
		    __right_split =
		      std::__stable_partition_adaptive(__right_split, __last, __pred,
						       __right_len,
						       __buffer, __buffer_size);
		  std::rotate(__left_split, __middle, __right_split);
		  std::advance(__left_split, std::distance(__middle, __right_split));
		  return __left_split;
		}
	    }
	
	  /**
	   *  @brief Move elements for which a predicate is true to the beginning
	   *         of a sequence, preserving relative ordering.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   A forward iterator.
	   *  @param  __last    A forward iterator.
	   *  @param  __pred    A predicate functor.
	   *  @return  An iterator @p middle such that @p __pred(i) is true for each
	   *  iterator @p i in the range @p [first,middle) and false for each @p i
	   *  in the range @p [middle,last).
	   *
	   *  Performs the same function as @p partition() with the additional
	   *  guarantee that the relative ordering of elements in each group is
	   *  preserved, so any two elements @p x and @p y in the range
	   *  @p [__first,__last) such that @p __pred(x)==__pred(y) will have the same
	   *  relative ordering after calling @p stable_partition().
	  */
	  template<typename _ForwardIterator, typename _Predicate>
	    _ForwardIterator
	    stable_partition(_ForwardIterator __first, _ForwardIterator __last,
			     _Predicate __pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
					  _ForwardIterator>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      __first = std::__find_if_not(__first, __last, __pred);
	
	      if (__first == __last)
		return __first;
	      else
		{
		  typedef typename iterator_traits<_ForwardIterator>::value_type
		    _ValueType;
		  typedef typename iterator_traits<_ForwardIterator>::difference_type
		    _DistanceType;
	
		  _Temporary_buffer<_ForwardIterator, _ValueType> __buf(__first,
									__last);
		if (__buf.size() > 0)
		  return
		    std::__stable_partition_adaptive(__first, __last, __pred,
						  _DistanceType(__buf.requested_size()),
						  __buf.begin(),
						  _DistanceType(__buf.size()));
		else
		  return
		    std::__inplace_stable_partition(__first, __pred,
						 _DistanceType(__buf.requested_size()));
		}
	    }
	
	  /// This is a helper function for the sort routines.
	  template<typename _RandomAccessIterator>
	    void
	    __heap_select(_RandomAccessIterator __first,
			  _RandomAccessIterator __middle,
			  _RandomAccessIterator __last)
	    {
	      std::make_heap(__first, __middle);
	      for (_RandomAccessIterator __i = __middle; __i < __last; ++__i)
		if (*__i < *__first)
		  std::__pop_heap(__first, __middle, __i);
	    }
	
	  /// This is a helper function for the sort routines.
	  template<typename _RandomAccessIterator, typename _Compare>
	    void
	    __heap_select(_RandomAccessIterator __first,
			  _RandomAccessIterator __middle,
			  _RandomAccessIterator __last, _Compare __comp)
	    {
	      std::make_heap(__first, __middle, __comp);
	      for (_RandomAccessIterator __i = __middle; __i < __last; ++__i)
		if (__comp(*__i, *__first))
		  std::__pop_heap(__first, __middle, __i, __comp);
	    }
	
	  // partial_sort
	
	  /**
	   *  @brief Copy the smallest elements of a sequence.
	   *  @ingroup sorting_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __result_first   A random-access iterator.
	   *  @param  __result_last    Another random-access iterator.
	   *  @return   An iterator indicating the end of the resulting sequence.
	   *
	   *  Copies and sorts the smallest N values from the range @p [__first,__last)
	   *  to the range beginning at @p __result_first, where the number of
	   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and
	   *  @p (__result_last-__result_first).
	   *  After the sort if @e i and @e j are iterators in the range
	   *  @p [__result_first,__result_first+N) such that i precedes j then
	   *  *j<*i is false.
	   *  The value returned is @p __result_first+N.
	  */
	  template<typename _InputIterator, typename _RandomAccessIterator>
	    _RandomAccessIterator
	    partial_sort_copy(_InputIterator __first, _InputIterator __last,
			      _RandomAccessIterator __result_first,
			      _RandomAccessIterator __result_last)
	    {
	      typedef typename iterator_traits<_InputIterator>::value_type
		_InputValueType;
	      typedef typename iterator_traits<_RandomAccessIterator>::value_type
		_OutputValueType;
	      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
		_DistanceType;
	
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
					  _OutputValueType>)
	      __glibcxx_function_requires(_LessThanOpConcept<_InputValueType,
					                     _OutputValueType>)
	      __glibcxx_function_requires(_LessThanComparableConcept<_OutputValueType>)
	      __glibcxx_requires_valid_range(__first, __last);
	      __glibcxx_requires_valid_range(__result_first, __result_last);
	
	      if (__result_first == __result_last)
		return __result_last;
	      _RandomAccessIterator __result_real_last = __result_first;
	      while(__first != __last && __result_real_last != __result_last)
		{
		  *__result_real_last = *__first;
		  ++__result_real_last;
		  ++__first;
		}
	      std::make_heap(__result_first, __result_real_last);
	      while (__first != __last)
		{
		  if (*__first < *__result_first)
		    std::__adjust_heap(__result_first, _DistanceType(0),
				       _DistanceType(__result_real_last
						     - __result_first),
				       _InputValueType(*__first));
		  ++__first;
		}
	      std::sort_heap(__result_first, __result_real_last);
	      return __result_real_last;
	    }
	
	  /**
	   *  @brief Copy the smallest elements of a sequence using a predicate for
	   *         comparison.
	   *  @ingroup sorting_algorithms
	   *  @param  __first   An input iterator.
	   *  @param  __last    Another input iterator.
	   *  @param  __result_first   A random-access iterator.
	   *  @param  __result_last    Another random-access iterator.
	   *  @param  __comp    A comparison functor.
	   *  @return   An iterator indicating the end of the resulting sequence.
	   *
	   *  Copies and sorts the smallest N values from the range @p [__first,__last)
	   *  to the range beginning at @p result_first, where the number of
	   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and
	   *  @p (__result_last-__result_first).
	   *  After the sort if @e i and @e j are iterators in the range
	   *  @p [__result_first,__result_first+N) such that i precedes j then
	   *  @p __comp(*j,*i) is false.
	   *  The value returned is @p __result_first+N.
	  */
	  template<typename _InputIterator, typename _RandomAccessIterator, typename _Compare>
	    _RandomAccessIterator
	    partial_sort_copy(_InputIterator __first, _InputIterator __last,
			      _RandomAccessIterator __result_first,
			      _RandomAccessIterator __result_last,
			      _Compare __comp)
	    {
	      typedef typename iterator_traits<_InputIterator>::value_type
		_InputValueType;
	      typedef typename iterator_traits<_RandomAccessIterator>::value_type
		_OutputValueType;
	      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
		_DistanceType;
	
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
					  _RandomAccessIterator>)
	      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,
					  _OutputValueType>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
					  _InputValueType, _OutputValueType>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
					  _OutputValueType, _OutputValueType>)
	      __glibcxx_requires_valid_range(__first, __last);
	      __glibcxx_requires_valid_range(__result_first, __result_last);
	
	      if (__result_first == __result_last)
		return __result_last;
	      _RandomAccessIterator __result_real_last = __result_first;
	      while(__first != __last && __result_real_last != __result_last)
		{
		  *__result_real_last = *__first;
		  ++__result_real_last;
		  ++__first;
		}
	      std::make_heap(__result_first, __result_real_last, __comp);
	      while (__first != __last)
		{
		  if (__comp(*__first, *__result_first))
		    std::__adjust_heap(__result_first, _DistanceType(0),
				       _DistanceType(__result_real_last
						     - __result_first),
				       _InputValueType(*__first),
				       __comp);
		  ++__first;
		}
	      std::sort_heap(__result_first, __result_real_last, __comp);
	      return __result_real_last;
	    }
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator>
	    void
	    __unguarded_linear_insert(_RandomAccessIterator __last)
	    {
	      typename iterator_traits<_RandomAccessIterator>::value_type
		__val = _GLIBCXX_MOVE(*__last);
	      _RandomAccessIterator __next = __last;
	      --__next;
	      while (__val < *__next)
		{
		  *__last = _GLIBCXX_MOVE(*__next);
		  __last = __next;
		  --__next;
		}
	      *__last = _GLIBCXX_MOVE(__val);
	    }
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator, typename _Compare>
	    void
	    __unguarded_linear_insert(_RandomAccessIterator __last,
				      _Compare __comp)
	    {
	      typename iterator_traits<_RandomAccessIterator>::value_type
		__val = _GLIBCXX_MOVE(*__last);
	      _RandomAccessIterator __next = __last;
	      --__next;
	      while (__comp(__val, *__next))
		{
		  *__last = _GLIBCXX_MOVE(*__next);
		  __last = __next;
		  --__next;
		}
	      *__last = _GLIBCXX_MOVE(__val);
	    }
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator>
	    void
	    __insertion_sort(_RandomAccessIterator __first,
			     _RandomAccessIterator __last)
	    {
	      if (__first == __last)
		return;
	
	      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
		{
		  if (*__i < *__first)
		    {
		      typename iterator_traits<_RandomAccessIterator>::value_type
			__val = _GLIBCXX_MOVE(*__i);
		      _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1);
		      *__first = _GLIBCXX_MOVE(__val);
		    }
		  else
		    std::__unguarded_linear_insert(__i);
		}
	    }
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator, typename _Compare>
	    void
	    __insertion_sort(_RandomAccessIterator __first,
			     _RandomAccessIterator __last, _Compare __comp)
	    {
	      if (__first == __last) return;
	
	      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
		{
		  if (__comp(*__i, *__first))
		    {
		      typename iterator_traits<_RandomAccessIterator>::value_type
			__val = _GLIBCXX_MOVE(*__i);
		      _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1);
		      *__first = _GLIBCXX_MOVE(__val);
		    }
		  else
		    std::__unguarded_linear_insert(__i, __comp);
		}
	    }
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator>
	    inline void
	    __unguarded_insertion_sort(_RandomAccessIterator __first,
				       _RandomAccessIterator __last)
	    {
	      typedef typename iterator_traits<_RandomAccessIterator>::value_type
		_ValueType;
	
	      for (_RandomAccessIterator __i = __first; __i != __last; ++__i)
		std::__unguarded_linear_insert(__i);
	    }
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator, typename _Compare>
	    inline void
	    __unguarded_insertion_sort(_RandomAccessIterator __first,
				       _RandomAccessIterator __last, _Compare __comp)
	    {
	      typedef typename iterator_traits<_RandomAccessIterator>::value_type
		_ValueType;
	
	      for (_RandomAccessIterator __i = __first; __i != __last; ++__i)
		std::__unguarded_linear_insert(__i, __comp);
	    }
	
	  /**
	   *  @doctodo
	   *  This controls some aspect of the sort routines.
	  */
	  enum { _S_threshold = 16 };
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator>
	    void
	    __final_insertion_sort(_RandomAccessIterator __first,
				   _RandomAccessIterator __last)
	    {
	      if (__last - __first > int(_S_threshold))
		{
		  std::__insertion_sort(__first, __first + int(_S_threshold));
		  std::__unguarded_insertion_sort(__first + int(_S_threshold), __last);
		}
	      else
		std::__insertion_sort(__first, __last);
	    }
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator, typename _Compare>
	    void
	    __final_insertion_sort(_RandomAccessIterator __first,
				   _RandomAccessIterator __last, _Compare __comp)
	    {
	      if (__last - __first > int(_S_threshold))
		{
		  std::__insertion_sort(__first, __first + int(_S_threshold), __comp);
		  std::__unguarded_insertion_sort(__first + int(_S_threshold), __last,
						  __comp);
		}
	      else
		std::__insertion_sort(__first, __last, __comp);
	    }
	
	  /// This is a helper function...
	  template<typename _RandomAccessIterator, typename _Tp>
	    _RandomAccessIterator
	    __unguarded_partition(_RandomAccessIterator __first,
				  _RandomAccessIterator __last, const _Tp& __pivot)
	    {
	      while (true)
		{
		  while (*__first < __pivot)
		    ++__first;
		  --__last;
		  while (__pivot < *__last)
		    --__last;
		  if (!(__first < __last))
		    return __first;
		  std::iter_swap(__first, __last);
		  ++__first;
		}
	    }
	
	  /// This is a helper function...
	  template<typename _RandomAccessIterator, typename _Tp, typename _Compare>
	    _RandomAccessIterator
	    __unguarded_partition(_RandomAccessIterator __first,
				  _RandomAccessIterator __last,
				  const _Tp& __pivot, _Compare __comp)
	    {
	      while (true)
		{
		  while (__comp(*__first, __pivot))
		    ++__first;
		  --__last;
		  while (__comp(__pivot, *__last))
		    --__last;
		  if (!(__first < __last))
		    return __first;
		  std::iter_swap(__first, __last);
		  ++__first;
		}
	    }
	
	  /// This is a helper function...
	  template<typename _RandomAccessIterator>
	    inline _RandomAccessIterator
	    __unguarded_partition_pivot(_RandomAccessIterator __first,
					_RandomAccessIterator __last)
	    {
	      _RandomAccessIterator __mid = __first + (__last - __first) / 2;
	      std::__move_median_to_first(__first, __first + 1, __mid, __last - 1);
	      return std::__unguarded_partition(__first + 1, __last, *__first);
	    }
	
	
	  /// This is a helper function...
	  template<typename _RandomAccessIterator, typename _Compare>
	    inline _RandomAccessIterator
	    __unguarded_partition_pivot(_RandomAccessIterator __first,
					_RandomAccessIterator __last, _Compare __comp)
	    {
	      _RandomAccessIterator __mid = __first + (__last - __first) / 2;
	      std::__move_median_to_first(__first, __first + 1, __mid, __last - 1,
					  __comp);
	      return std::__unguarded_partition(__first + 1, __last, *__first, __comp);
	    }
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator, typename _Size>
	    void
	    __introsort_loop(_RandomAccessIterator __first,
			     _RandomAccessIterator __last,
			     _Size __depth_limit)
	    {
	      while (__last - __first > int(_S_threshold))
		{
		  if (__depth_limit == 0)
		    {
		      _GLIBCXX_STD_A::partial_sort(__first, __last, __last);
		      return;
		    }
		  --__depth_limit;
		  _RandomAccessIterator __cut =
		    std::__unguarded_partition_pivot(__first, __last);
		  std::__introsort_loop(__cut, __last, __depth_limit);
		  __last = __cut;
		}
	    }
	
	  /// This is a helper function for the sort routine.
	  template<typename _RandomAccessIterator, typename _Size, typename _Compare>
	    void
	    __introsort_loop(_RandomAccessIterator __first,
			     _RandomAccessIterator __last,
			     _Size __depth_limit, _Compare __comp)
	    {
	      while (__last - __first > int(_S_threshold))
		{
		  if (__depth_limit == 0)
		    {
		      _GLIBCXX_STD_A::partial_sort(__first, __last, __last, __comp);
		      return;
		    }
		  --__depth_limit;
		  _RandomAccessIterator __cut =
		    std::__unguarded_partition_pivot(__first, __last, __comp);
		  std::__introsort_loop(__cut, __last, __depth_limit, __comp);
		  __last = __cut;
		}
	    }
	
	  // sort
	
	  template<typename _RandomAccessIterator, typename _Size>
	    void
	    __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth,
			  _RandomAccessIterator __last, _Size __depth_limit)
	    {
	      typedef typename iterator_traits<_RandomAccessIterator>::value_type
		_ValueType;
	
	      while (__last - __first > 3)
		{
		  if (__depth_limit == 0)
		    {
		      std::__heap_select(__first, __nth + 1, __last);
	
		      // Place the nth largest element in its final position.
		      std::iter_swap(__first, __nth);
		      return;
		    }
		  --__depth_limit;
		  _RandomAccessIterator __cut =
		    std::__unguarded_partition_pivot(__first, __last);
		  if (__cut <= __nth)
		    __first = __cut;
		  else
		    __last = __cut;
		}
	      std::__insertion_sort(__first, __last);
	    }
	
	  template<typename _RandomAccessIterator, typename _Size, typename _Compare>
	    void
	    __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth,
			  _RandomAccessIterator __last, _Size __depth_limit,
			  _Compare __comp)
	    {
	      typedef typename iterator_traits<_RandomAccessIterator>::value_type
		_ValueType;
	
	      while (__last - __first > 3)
		{
		  if (__depth_limit == 0)
		    {
		      std::__heap_select(__first, __nth + 1, __last, __comp);
		      // Place the nth largest element in its final position.
		      std::iter_swap(__first, __nth);
		      return;
		    }
		  --__depth_limit;
		  _RandomAccessIterator __cut =
		    std::__unguarded_partition_pivot(__first, __last, __comp);
		  if (__cut <= __nth)
		    __first = __cut;
		  else
		    __last = __cut;
		}
	      std::__insertion_sort(__first, __last, __comp);
	    }
	
	  // nth_element
	
	  // lower_bound moved to stl_algobase.h
	
	  /**
	   *  @brief Finds the first position in which @p __val could be inserted
	   *         without changing the ordering.
	   *  @ingroup binary_search_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __val     The search term.
	   *  @param  __comp    A functor to use for comparisons.
	   *  @return An iterator pointing to the first element <em>not less
	   *           than</em> @p __val, or end() if every element is less
	   *           than @p __val.
	   *  @ingroup binary_search_algorithms
	   *
	   *  The comparison function should have the same effects on ordering as
	   *  the function used for the initial sort.
	  */
	  template<typename _ForwardIterator, typename _Tp, typename _Compare>
	    _ForwardIterator
	    lower_bound(_ForwardIterator __first, _ForwardIterator __last,
			const _Tp& __val, _Compare __comp)
	    {
	      typedef typename iterator_traits<_ForwardIterator>::value_type
		_ValueType;
	      typedef typename iterator_traits<_ForwardIterator>::difference_type
		_DistanceType;
	
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
					  _ValueType, _Tp>)
	      __glibcxx_requires_partitioned_lower_pred(__first, __last,
							__val, __comp);
	
	      _DistanceType __len = std::distance(__first, __last);
	
	      while (__len > 0)
		{
		  _DistanceType __half = __len >> 1;
		  _ForwardIterator __middle = __first;
		  std::advance(__middle, __half);
		  if (__comp(*__middle, __val))
		    {
		      __first = __middle;
		      ++__first;
		      __len = __len - __half - 1;
		    }
		  else
		    __len = __half;
		}
	      return __first;
	    }
	
	  /**
	   *  @brief Finds the last position in which @p __val could be inserted
	   *         without changing the ordering.
	   *  @ingroup binary_search_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __val     The search term.
	   *  @return  An iterator pointing to the first element greater than @p __val,
	   *           or end() if no elements are greater than @p __val.
	   *  @ingroup binary_search_algorithms
	  */
	  template<typename _ForwardIterator, typename _Tp>
	    _ForwardIterator
	    upper_bound(_ForwardIterator __first, _ForwardIterator __last,
			const _Tp& __val)
	    {
	      typedef typename iterator_traits<_ForwardIterator>::value_type
		_ValueType;
	      typedef typename iterator_traits<_ForwardIterator>::difference_type
		_DistanceType;
	
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_LessThanOpConcept<_Tp, _ValueType>)
	      __glibcxx_requires_partitioned_upper(__first, __last, __val);
	
	      _DistanceType __len = std::distance(__first, __last);
	
	      while (__len > 0)
		{
		  _DistanceType __half = __len >> 1;
		  _ForwardIterator __middle = __first;
		  std::advance(__middle, __half);
		  if (__val < *__middle)
		    __len = __half;
		  else
		    {
		      __first = __middle;
		      ++__first;
		      __len = __len - __half - 1;
		    }
		}
	      return __first;
	    }
	
	  /**
	   *  @brief Finds the last position in which @p __val could be inserted
	   *         without changing the ordering.
	   *  @ingroup binary_search_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __val     The search term.
	   *  @param  __comp    A functor to use for comparisons.
	   *  @return  An iterator pointing to the first element greater than @p __val,
	   *           or end() if no elements are greater than @p __val.
	   *  @ingroup binary_search_algorithms
	   *
	   *  The comparison function should have the same effects on ordering as
	   *  the function used for the initial sort.
	  */
	  template<typename _ForwardIterator, typename _Tp, typename _Compare>
	    _ForwardIterator
	    upper_bound(_ForwardIterator __first, _ForwardIterator __last,
			const _Tp& __val, _Compare __comp)
	    {
	      typedef typename iterator_traits<_ForwardIterator>::value_type
		_ValueType;
	      typedef typename iterator_traits<_ForwardIterator>::difference_type
		_DistanceType;
	
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
					  _Tp, _ValueType>)
	      __glibcxx_requires_partitioned_upper_pred(__first, __last,
							__val, __comp);
	
	      _DistanceType __len = std::distance(__first, __last);
	
	      while (__len > 0)
		{
		  _DistanceType __half = __len >> 1;
		  _ForwardIterator __middle = __first;
		  std::advance(__middle, __half);
		  if (__comp(__val, *__middle))
		    __len = __half;
		  else
		    {
		      __first = __middle;
		      ++__first;
		      __len = __len - __half - 1;
		    }
		}
	      return __first;
	    }
	
	  /**
	   *  @brief Finds the largest subrange in which @p __val could be inserted
	   *         at any place in it without changing the ordering.
	   *  @ingroup binary_search_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __val     The search term.
	   *  @return  An pair of iterators defining the subrange.
	   *  @ingroup binary_search_algorithms
	   *
	   *  This is equivalent to
	   *  @code
	   *    std::make_pair(lower_bound(__first, __last, __val),
	   *                   upper_bound(__first, __last, __val))
	   *  @endcode
	   *  but does not actually call those functions.
	  */
	  template<typename _ForwardIterator, typename _Tp>
	    pair<_ForwardIterator, _ForwardIterator>
	    equal_range(_ForwardIterator __first, _ForwardIterator __last,
			const _Tp& __val)
	    {
	      typedef typename iterator_traits<_ForwardIterator>::value_type
		_ValueType;
	      typedef typename iterator_traits<_ForwardIterator>::difference_type
		_DistanceType;
	
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_LessThanOpConcept<_ValueType, _Tp>)
	      __glibcxx_function_requires(_LessThanOpConcept<_Tp, _ValueType>)	
	      __glibcxx_requires_partitioned_lower(__first, __last, __val);
	      __glibcxx_requires_partitioned_upper(__first, __last, __val);      
	
	      _DistanceType __len = std::distance(__first, __last);
	 
	      while (__len > 0)
		{
		  _DistanceType __half = __len >> 1;
		  _ForwardIterator __middle = __first;
		  std::advance(__middle, __half);
		  if (*__middle < __val)
		    {
		      __first = __middle;
		      ++__first;
		      __len = __len - __half - 1;
		    }
		  else if (__val < *__middle)
		    __len = __half;
		  else
		    {
		      _ForwardIterator __left = std::lower_bound(__first, __middle,
								 __val);
		      std::advance(__first, __len);
		      _ForwardIterator __right = std::upper_bound(++__middle, __first,
								  __val);
		      return pair<_ForwardIterator, _ForwardIterator>(__left, __right);
		    }
		}
	      return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
	    }
	
	  /**
	   *  @brief Finds the largest subrange in which @p __val could be inserted
	   *         at any place in it without changing the ordering.
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __val     The search term.
	   *  @param  __comp    A functor to use for comparisons.
	   *  @return  An pair of iterators defining the subrange.
	   *  @ingroup binary_search_algorithms
	   *
	   *  This is equivalent to
	   *  @code
	   *    std::make_pair(lower_bound(__first, __last, __val, __comp),
	   *                   upper_bound(__first, __last, __val, __comp))
	   *  @endcode
	   *  but does not actually call those functions.
	  */
	  template<typename _ForwardIterator, typename _Tp, typename _Compare>
	    pair<_ForwardIterator, _ForwardIterator>
	    equal_range(_ForwardIterator __first, _ForwardIterator __last,
			const _Tp& __val, _Compare __comp)
	    {
	      typedef typename iterator_traits<_ForwardIterator>::value_type
		_ValueType;
	      typedef typename iterator_traits<_ForwardIterator>::difference_type
		_DistanceType;
	
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
					  _ValueType, _Tp>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
					  _Tp, _ValueType>)
	      __glibcxx_requires_partitioned_lower_pred(__first, __last,
							__val, __comp);
	      __glibcxx_requires_partitioned_upper_pred(__first, __last,
							__val, __comp);
	
	      _DistanceType __len = std::distance(__first, __last);
	
	      while (__len > 0)
		{
		  _DistanceType __half = __len >> 1;
		  _ForwardIterator __middle = __first;
		  std::advance(__middle, __half);
		  if (__comp(*__middle, __val))
		    {
		      __first = __middle;
		      ++__first;
		      __len = __len - __half - 1;
		    }
		  else if (__comp(__val, *__middle))
		    __len = __half;
		  else
		    {
		      _ForwardIterator __left = std::lower_bound(__first, __middle,
								 __val, __comp);
		      std::advance(__first, __len);
		      _ForwardIterator __right = std::upper_bound(++__middle, __first,
								  __val, __comp);
		      return pair<_ForwardIterator, _ForwardIterator>(__left, __right);
		    }
		}
	      return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
	    }
	
	  /**
	   *  @brief Determines whether an element exists in a range.
	   *  @ingroup binary_search_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __val     The search term.
	   *  @return True if @p __val (or its equivalent) is in [@p
	   *  __first,@p __last ].
	   *
	   *  Note that this does not actually return an iterator to @p __val.  For
	   *  that, use std::find or a container's specialized find member functions.
	  */
	  template<typename _ForwardIterator, typename _Tp>
	    bool
	    binary_search(_ForwardIterator __first, _ForwardIterator __last,
	                  const _Tp& __val)
	    {
	      typedef typename iterator_traits<_ForwardIterator>::value_type
		_ValueType;
	
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_LessThanOpConcept<_Tp, _ValueType>)
	      __glibcxx_requires_partitioned_lower(__first, __last, __val);
	      __glibcxx_requires_partitioned_upper(__first, __last, __val);
	
	      _ForwardIterator __i = std::lower_bound(__first, __last, __val);
	      return __i != __last && !(__val < *__i);
	    }
	
	  /**
	   *  @brief Determines whether an element exists in a range.
	   *  @ingroup binary_search_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __val     The search term.
	   *  @param  __comp    A functor to use for comparisons.
	   *  @return  True if @p __val (or its equivalent) is in @p [__first,__last].
	   *
	   *  Note that this does not actually return an iterator to @p __val.  For
	   *  that, use std::find or a container's specialized find member functions.
	   *
	   *  The comparison function should have the same effects on ordering as
	   *  the function used for the initial sort.
	  */
	  template<typename _ForwardIterator, typename _Tp, typename _Compare>
	    bool
	    binary_search(_ForwardIterator __first, _ForwardIterator __last,
	                  const _Tp& __val, _Compare __comp)
	    {
	      typedef typename iterator_traits<_ForwardIterator>::value_type
		_ValueType;
	
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
					  _Tp, _ValueType>)
	      __glibcxx_requires_partitioned_lower_pred(__first, __last,
							__val, __comp);
	      __glibcxx_requires_partitioned_upper_pred(__first, __last,
							__val, __comp);
	
	      _ForwardIterator __i = std::lower_bound(__first, __last, __val, __comp);
	      return __i != __last && !bool(__comp(__val, *__i));
	    }
	
	  // merge
	
	  /// This is a helper function for the __merge_adaptive routines.
	  template<typename _InputIterator1, typename _InputIterator2,
		   typename _OutputIterator>
	    void
	    __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1,
				  _InputIterator2 __first2, _InputIterator2 __last2,
				  _OutputIterator __result)
	    {
	      while (__first1 != __last1 && __first2 != __last2)
		{
		  if (*__first2 < *__first1)
		    {
		      *__result = _GLIBCXX_MOVE(*__first2);
		      ++__first2;
		    }
		  else
		    {
		      *__result = _GLIBCXX_MOVE(*__first1);
		      ++__first1;
		    }
		  ++__result;
		}
	      if (__first1 != __last1)
		_GLIBCXX_MOVE3(__first1, __last1, __result);
	    }
	
	  /// This is a helper function for the __merge_adaptive routines.
	  template<typename _InputIterator1, typename _InputIterator2,
		   typename _OutputIterator, typename _Compare>
	    void
	    __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1,
				  _InputIterator2 __first2, _InputIterator2 __last2,
				  _OutputIterator __result, _Compare __comp)
	    {
	      while (__first1 != __last1 && __first2 != __last2)
		{
		  if (__comp(*__first2, *__first1))
		    {
		      *__result = _GLIBCXX_MOVE(*__first2);
		      ++__first2;
		    }
		  else
		    {
		      *__result = _GLIBCXX_MOVE(*__first1);
		      ++__first1;
		    }
		  ++__result;
		}
	      if (__first1 != __last1)
		_GLIBCXX_MOVE3(__first1, __last1, __result);
	    }
	
	  /// This is a helper function for the __merge_adaptive routines.
	  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
		   typename _BidirectionalIterator3>
	    void
	    __move_merge_adaptive_backward(_BidirectionalIterator1 __first1,
					   _BidirectionalIterator1 __last1,
					   _BidirectionalIterator2 __first2,
					   _BidirectionalIterator2 __last2,
					   _BidirectionalIterator3 __result)
	    {
	      if (__first1 == __last1)
		{
		  _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result);
		  return;
		}
	      else if (__first2 == __last2)
		return;
	
	      --__last1;
	      --__last2;
	      while (true)
		{
		  if (*__last2 < *__last1)
		    {
		      *--__result = _GLIBCXX_MOVE(*__last1);
		      if (__first1 == __last1)
			{
			  _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result);
			  return;
			}
		      --__last1;
		    }
		  else
		    {
		      *--__result = _GLIBCXX_MOVE(*__last2);
		      if (__first2 == __last2)
			return;
		      --__last2;
		    }
		}
	    }
	
	  /// This is a helper function for the __merge_adaptive routines.
	  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
		   typename _BidirectionalIterator3, typename _Compare>
	    void
	    __move_merge_adaptive_backward(_BidirectionalIterator1 __first1,
					   _BidirectionalIterator1 __last1,
					   _BidirectionalIterator2 __first2,
					   _BidirectionalIterator2 __last2,
					   _BidirectionalIterator3 __result,
					   _Compare __comp)
	    {
	      if (__first1 == __last1)
		{
		  _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result);
		  return;
		}
	      else if (__first2 == __last2)
		return;
	
	      --__last1;
	      --__last2;
	      while (true)
		{
		  if (__comp(*__last2, *__last1))
		    {
		      *--__result = _GLIBCXX_MOVE(*__last1);
		      if (__first1 == __last1)
			{
			  _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result);
			  return;
			}
		      --__last1;
		    }
		  else
		    {
		      *--__result = _GLIBCXX_MOVE(*__last2);
		      if (__first2 == __last2)
			return;
		      --__last2;
		    }
		}
	    }
	
	  /// This is a helper function for the merge routines.
	  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,
		   typename _Distance>
	    _BidirectionalIterator1
	    __rotate_adaptive(_BidirectionalIterator1 __first,
			      _BidirectionalIterator1 __middle,
			      _BidirectionalIterator1 __last,
			      _Distance __len1, _Distance __len2,
			      _BidirectionalIterator2 __buffer,
			      _Distance __buffer_size)
	    {
	      _BidirectionalIterator2 __buffer_end;
	      if (__len1 > __len2 && __len2 <= __buffer_size)
		{
		  if (__len2)
		    {
		      __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
		      _GLIBCXX_MOVE_BACKWARD3(__first, __middle, __last);
		      return _GLIBCXX_MOVE3(__buffer, __buffer_end, __first);
		    }
		  else
		    return __first;
		}
	      else if (__len1 <= __buffer_size)
		{
		  if (__len1)
		    {
		      __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
		      _GLIBCXX_MOVE3(__middle, __last, __first);
		      return _GLIBCXX_MOVE_BACKWARD3(__buffer, __buffer_end, __last);
		    }
		  else
		    return __last;
		}
	      else
		{
		  std::rotate(__first, __middle, __last);
		  std::advance(__first, std::distance(__middle, __last));
		  return __first;
		}
	    }
	
	  /// This is a helper function for the merge routines.
	  template<typename _BidirectionalIterator, typename _Distance,
		   typename _Pointer>
	    void
	    __merge_adaptive(_BidirectionalIterator __first,
	                     _BidirectionalIterator __middle,
			     _BidirectionalIterator __last,
			     _Distance __len1, _Distance __len2,
			     _Pointer __buffer, _Distance __buffer_size)
	    {
	      if (__len1 <= __len2 && __len1 <= __buffer_size)
		{
		  _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
		  std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last,
					     __first);
		}
	      else if (__len2 <= __buffer_size)
		{
		  _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
		  std::__move_merge_adaptive_backward(__first, __middle, __buffer,
						      __buffer_end, __last);
		}
	      else
		{
		  _BidirectionalIterator __first_cut = __first;
		  _BidirectionalIterator __second_cut = __middle;
		  _Distance __len11 = 0;
		  _Distance __len22 = 0;
		  if (__len1 > __len2)
		    {
		      __len11 = __len1 / 2;
		      std::advance(__first_cut, __len11);
		      __second_cut = std::lower_bound(__middle, __last,
						      *__first_cut);
		      __len22 = std::distance(__middle, __second_cut);
		    }
		  else
		    {
		      __len22 = __len2 / 2;
		      std::advance(__second_cut, __len22);
		      __first_cut = std::upper_bound(__first, __middle,
						     *__second_cut);
		      __len11 = std::distance(__first, __first_cut);
		    }
		  _BidirectionalIterator __new_middle =
		    std::__rotate_adaptive(__first_cut, __middle, __second_cut,
					   __len1 - __len11, __len22, __buffer,
					   __buffer_size);
		  std::__merge_adaptive(__first, __first_cut, __new_middle, __len11,
					__len22, __buffer, __buffer_size);
		  std::__merge_adaptive(__new_middle, __second_cut, __last,
					__len1 - __len11,
					__len2 - __len22, __buffer, __buffer_size);
		}
	    }
	
	  /// This is a helper function for the merge routines.
	  template<typename _BidirectionalIterator, typename _Distance, 
		   typename _Pointer, typename _Compare>
	    void
	    __merge_adaptive(_BidirectionalIterator __first,
	                     _BidirectionalIterator __middle,
			     _BidirectionalIterator __last,
			     _Distance __len1, _Distance __len2,
			     _Pointer __buffer, _Distance __buffer_size,
			     _Compare __comp)
	    {
	      if (__len1 <= __len2 && __len1 <= __buffer_size)
		{
		  _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);
		  std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last,
					     __first, __comp);
		}
	      else if (__len2 <= __buffer_size)
		{
		  _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);
		  std::__move_merge_adaptive_backward(__first, __middle, __buffer,
						      __buffer_end, __last, __comp);
		}
	      else
		{
		  _BidirectionalIterator __first_cut = __first;
		  _BidirectionalIterator __second_cut = __middle;
		  _Distance __len11 = 0;
		  _Distance __len22 = 0;
		  if (__len1 > __len2)
		    {
		      __len11 = __len1 / 2;
		      std::advance(__first_cut, __len11);
		      __second_cut = std::lower_bound(__middle, __last, *__first_cut,
						      __comp);
		      __len22 = std::distance(__middle, __second_cut);
		    }
		  else
		    {
		      __len22 = __len2 / 2;
		      std::advance(__second_cut, __len22);
		      __first_cut = std::upper_bound(__first, __middle, *__second_cut,
						     __comp);
		      __len11 = std::distance(__first, __first_cut);
		    }
		  _BidirectionalIterator __new_middle =
		    std::__rotate_adaptive(__first_cut, __middle, __second_cut,
					   __len1 - __len11, __len22, __buffer,
					   __buffer_size);
		  std::__merge_adaptive(__first, __first_cut, __new_middle, __len11,
					__len22, __buffer, __buffer_size, __comp);
		  std::__merge_adaptive(__new_middle, __second_cut, __last,
					__len1 - __len11,
					__len2 - __len22, __buffer,
					__buffer_size, __comp);
		}
	    }
	
	  /// This is a helper function for the merge routines.
	  template<typename _BidirectionalIterator, typename _Distance>
	    void
	    __merge_without_buffer(_BidirectionalIterator __first,
				   _BidirectionalIterator __middle,
				   _BidirectionalIterator __last,
				   _Distance __len1, _Distance __len2)
	    {
	      if (__len1 == 0 || __len2 == 0)
		return;
	      if (__len1 + __len2 == 2)
		{
		  if (*__middle < *__first)
		    std::iter_swap(__first, __middle);
		  return;
		}
	      _BidirectionalIterator __first_cut = __first;
	      _BidirectionalIterator __second_cut = __middle;
	      _Distance __len11 = 0;
	      _Distance __len22 = 0;
	      if (__len1 > __len2)
		{
		  __len11 = __len1 / 2;
		  std::advance(__first_cut, __len11);
		  __second_cut = std::lower_bound(__middle, __last, *__first_cut);
		  __len22 = std::distance(__middle, __second_cut);
		}
	      else
		{
		  __len22 = __len2 / 2;
		  std::advance(__second_cut, __len22);
		  __first_cut = std::upper_bound(__first, __middle, *__second_cut);
		  __len11 = std::distance(__first, __first_cut);
		}
	      std::rotate(__first_cut, __middle, __second_cut);
	      _BidirectionalIterator __new_middle = __first_cut;
	      std::advance(__new_middle, std::distance(__middle, __second_cut));
	      std::__merge_without_buffer(__first, __first_cut, __new_middle,
					  __len11, __len22);
	      std::__merge_without_buffer(__new_middle, __second_cut, __last,
					  __len1 - __len11, __len2 - __len22);
	    }
	
	  /// This is a helper function for the merge routines.
	  template<typename _BidirectionalIterator, typename _Distance,
		   typename _Compare>
	    void
	    __merge_without_buffer(_BidirectionalIterator __first,
	                           _BidirectionalIterator __middle,
				   _BidirectionalIterator __last,
				   _Distance __len1, _Distance __len2,
				   _Compare __comp)
	    {
	      if (__len1 == 0 || __len2 == 0)
		return;
	      if (__len1 + __len2 == 2)
		{
		  if (__comp(*__middle, *__first))
		    std::iter_swap(__first, __middle);
		  return;
		}
	      _BidirectionalIterator __first_cut = __first;
	      _BidirectionalIterator __second_cut = __middle;
	      _Distance __len11 = 0;
	      _Distance __len22 = 0;
	      if (__len1 > __len2)
		{
		  __len11 = __len1 / 2;
		  std::advance(__first_cut, __len11);
		  __second_cut = std::lower_bound(__middle, __last, *__first_cut,
						  __comp);
		  __len22 = std::distance(__middle, __second_cut);
		}
	      else
		{
		  __len22 = __len2 / 2;
		  std::advance(__second_cut, __len22);
		  __first_cut = std::upper_bound(__first, __middle, *__second_cut,
						 __comp);
		  __len11 = std::distance(__first, __first_cut);
		}
	      std::rotate(__first_cut, __middle, __second_cut);
	      _BidirectionalIterator __new_middle = __first_cut;
	      std::advance(__new_middle, std::distance(__middle, __second_cut));
	      std::__merge_without_buffer(__first, __first_cut, __new_middle,
					  __len11, __len22, __comp);
	      std::__merge_without_buffer(__new_middle, __second_cut, __last,
					  __len1 - __len11, __len2 - __len22, __comp);
	    }
	
	  /**
	   *  @brief Merges two sorted ranges in place.
	   *  @ingroup sorting_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __middle  Another iterator.
	   *  @param  __last    Another iterator.
	   *  @return  Nothing.
	   *
	   *  Merges two sorted and consecutive ranges, [__first,__middle) and
	   *  [__middle,__last), and puts the result in [__first,__last).  The
	   *  output will be sorted.  The sort is @e stable, that is, for
	   *  equivalent elements in the two ranges, elements from the first
	   *  range will always come before elements from the second.
	   *
	   *  If enough additional memory is available, this takes (__last-__first)-1
	   *  comparisons.  Otherwise an NlogN algorithm is used, where N is
	   *  distance(__first,__last).
	  */
	  template<typename _BidirectionalIterator>
	    void
	    inplace_merge(_BidirectionalIterator __first,
			  _BidirectionalIterator __middle,
			  _BidirectionalIterator __last)
	    {
	      typedef typename iterator_traits<_BidirectionalIterator>::value_type
	          _ValueType;
	      typedef typename iterator_traits<_BidirectionalIterator>::difference_type
	          _DistanceType;
	
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
		    _BidirectionalIterator>)
	      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
	      __glibcxx_requires_sorted(__first, __middle);
	      __glibcxx_requires_sorted(__middle, __last);
	
	      if (__first == __middle || __middle == __last)
		return;
	
	      _DistanceType __len1 = std::distance(__first, __middle);
	      _DistanceType __len2 = std::distance(__middle, __last);
	
	      _Temporary_buffer<_BidirectionalIterator, _ValueType> __buf(__first,
									  __last);
	      if (__buf.begin() == 0)
		std::__merge_without_buffer(__first, __middle, __last, __len1, __len2);
	      else
		std::__merge_adaptive(__first, __middle, __last, __len1, __len2,
				      __buf.begin(), _DistanceType(__buf.size()));
	    }
	
	  /**
	   *  @brief Merges two sorted ranges in place.
	   *  @ingroup sorting_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __middle  Another iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __comp    A functor to use for comparisons.
	   *  @return  Nothing.
	   *
	   *  Merges two sorted and consecutive ranges, [__first,__middle) and
	   *  [middle,last), and puts the result in [__first,__last).  The output will
	   *  be sorted.  The sort is @e stable, that is, for equivalent
	   *  elements in the two ranges, elements from the first range will always
	   *  come before elements from the second.
	   *
	   *  If enough additional memory is available, this takes (__last-__first)-1
	   *  comparisons.  Otherwise an NlogN algorithm is used, where N is
	   *  distance(__first,__last).
	   *
	   *  The comparison function should have the same effects on ordering as
	   *  the function used for the initial sort.
	  */
	  template<typename _BidirectionalIterator, typename _Compare>
	    void
	    inplace_merge(_BidirectionalIterator __first,
			  _BidirectionalIterator __middle,
			  _BidirectionalIterator __last,
			  _Compare __comp)
	    {
	      typedef typename iterator_traits<_BidirectionalIterator>::value_type
	          _ValueType;
	      typedef typename iterator_traits<_BidirectionalIterator>::difference_type
	          _DistanceType;
	
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<
		    _BidirectionalIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
		    _ValueType, _ValueType>)
	      __glibcxx_requires_sorted_pred(__first, __middle, __comp);
	      __glibcxx_requires_sorted_pred(__middle, __last, __comp);
	
	      if (__first == __middle || __middle == __last)
		return;
	
	      const _DistanceType __len1 = std::distance(__first, __middle);
	      const _DistanceType __len2 = std::distance(__middle, __last);
	
	      _Temporary_buffer<_BidirectionalIterator, _ValueType> __buf(__first,
									  __last);
	      if (__buf.begin() == 0)
		std::__merge_without_buffer(__first, __middle, __last, __len1,
					    __len2, __comp);
	      else
		std::__merge_adaptive(__first, __middle, __last, __len1, __len2,
				      __buf.begin(), _DistanceType(__buf.size()),
				      __comp);
	    }
	
	
	  /// This is a helper function for the __merge_sort_loop routines.
	  template<typename _InputIterator1, typename _InputIterator2,
		   typename _OutputIterator>
	    _OutputIterator
	    __move_merge(_InputIterator1 __first1, _InputIterator1 __last1,
			 _InputIterator2 __first2, _InputIterator2 __last2,
			 _OutputIterator __result)
	    {
	      while (__first1 != __last1 && __first2 != __last2)
		{
		  if (*__first2 < *__first1)
		    {
		      *__result = _GLIBCXX_MOVE(*__first2);
		      ++__first2;
		    }
		  else
		    {
		      *__result = _GLIBCXX_MOVE(*__first1);
		      ++__first1;
		    }
		  ++__result;
		}
	      return _GLIBCXX_MOVE3(__first2, __last2,
				    _GLIBCXX_MOVE3(__first1, __last1,
						   __result));
	    }
	
	  /// This is a helper function for the __merge_sort_loop routines.
	  template<typename _InputIterator1, typename _InputIterator2,
		   typename _OutputIterator, typename _Compare>
	    _OutputIterator
	    __move_merge(_InputIterator1 __first1, _InputIterator1 __last1,
			 _InputIterator2 __first2, _InputIterator2 __last2,
			 _OutputIterator __result, _Compare __comp)
	    {
	      while (__first1 != __last1 && __first2 != __last2)
		{
		  if (__comp(*__first2, *__first1))
		    {
		      *__result = _GLIBCXX_MOVE(*__first2);
		      ++__first2;
		    }
		  else
		    {
		      *__result = _GLIBCXX_MOVE(*__first1);
		      ++__first1;
		    }
		  ++__result;
		}
	      return _GLIBCXX_MOVE3(__first2, __last2,
				    _GLIBCXX_MOVE3(__first1, __last1,
						   __result));
	    }
	
	  template<typename _RandomAccessIterator1, typename _RandomAccessIterator2,
		   typename _Distance>
	    void
	    __merge_sort_loop(_RandomAccessIterator1 __first,
			      _RandomAccessIterator1 __last,
			      _RandomAccessIterator2 __result,
			      _Distance __step_size)
	    {
	      const _Distance __two_step = 2 * __step_size;
	
	      while (__last - __first >= __two_step)
		{
		  __result = std::__move_merge(__first, __first + __step_size,
					       __first + __step_size,
					       __first + __two_step, __result);
		  __first += __two_step;
		}
	
	      __step_size = std::min(_Distance(__last - __first), __step_size);
	      std::__move_merge(__first, __first + __step_size,
				__first + __step_size, __last, __result);
	    }
	
	  template<typename _RandomAccessIterator1, typename _RandomAccessIterator2,
		   typename _Distance, typename _Compare>
	    void
	    __merge_sort_loop(_RandomAccessIterator1 __first,
			      _RandomAccessIterator1 __last,
			      _RandomAccessIterator2 __result, _Distance __step_size,
			      _Compare __comp)
	    {
	      const _Distance __two_step = 2 * __step_size;
	
	      while (__last - __first >= __two_step)
		{
		  __result = std::__move_merge(__first, __first + __step_size,
					       __first + __step_size,
					       __first + __two_step,
					       __result, __comp);
		  __first += __two_step;
		}
	      __step_size = std::min(_Distance(__last - __first), __step_size);
	
	      std::__move_merge(__first,__first + __step_size,
				__first + __step_size, __last, __result, __comp);
	    }
	
	  template<typename _RandomAccessIterator, typename _Distance>
	    void
	    __chunk_insertion_sort(_RandomAccessIterator __first,
				   _RandomAccessIterator __last,
				   _Distance __chunk_size)
	    {
	      while (__last - __first >= __chunk_size)
		{
		  std::__insertion_sort(__first, __first + __chunk_size);
		  __first += __chunk_size;
		}
	      std::__insertion_sort(__first, __last);
	    }
	
	  template<typename _RandomAccessIterator, typename _Distance,
		   typename _Compare>
	    void
	    __chunk_insertion_sort(_RandomAccessIterator __first,
				   _RandomAccessIterator __last,
				   _Distance __chunk_size, _Compare __comp)
	    {
	      while (__last - __first >= __chunk_size)
		{
		  std::__insertion_sort(__first, __first + __chunk_size, __comp);
		  __first += __chunk_size;
		}
	      std::__insertion_sort(__first, __last, __comp);
	    }
	
	  enum { _S_chunk_size = 7 };
	
	  template<typename _RandomAccessIterator, typename _Pointer>
	    void
	    __merge_sort_with_buffer(_RandomAccessIterator __first,
				     _RandomAccessIterator __last,
	                             _Pointer __buffer)
	    {
	      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
		_Distance;
	
	      const _Distance __len = __last - __first;
	      const _Pointer __buffer_last = __buffer + __len;
	
	      _Distance __step_size = _S_chunk_size;
	      std::__chunk_insertion_sort(__first, __last, __step_size);
	
	      while (__step_size < __len)
		{
		  std::__merge_sort_loop(__first, __last, __buffer, __step_size);
		  __step_size *= 2;
		  std::__merge_sort_loop(__buffer, __buffer_last, __first, __step_size);
		  __step_size *= 2;
		}
	    }
	
	  template<typename _RandomAccessIterator, typename _Pointer, typename _Compare>
	    void
	    __merge_sort_with_buffer(_RandomAccessIterator __first,
				     _RandomAccessIterator __last,
	                             _Pointer __buffer, _Compare __comp)
	    {
	      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
		_Distance;
	
	      const _Distance __len = __last - __first;
	      const _Pointer __buffer_last = __buffer + __len;
	
	      _Distance __step_size = _S_chunk_size;
	      std::__chunk_insertion_sort(__first, __last, __step_size, __comp);
	
	      while (__step_size < __len)
		{
		  std::__merge_sort_loop(__first, __last, __buffer,
					 __step_size, __comp);
		  __step_size *= 2;
		  std::__merge_sort_loop(__buffer, __buffer_last, __first,
					 __step_size, __comp);
		  __step_size *= 2;
		}
	    }
	
	  template<typename _RandomAccessIterator, typename _Pointer,
		   typename _Distance>
	    void
	    __stable_sort_adaptive(_RandomAccessIterator __first,
				   _RandomAccessIterator __last,
	                           _Pointer __buffer, _Distance __buffer_size)
	    {
	      const _Distance __len = (__last - __first + 1) / 2;
	      const _RandomAccessIterator __middle = __first + __len;
	      if (__len > __buffer_size)
		{
		  std::__stable_sort_adaptive(__first, __middle,
					      __buffer, __buffer_size);
		  std::__stable_sort_adaptive(__middle, __last,
					      __buffer, __buffer_size);
		}
	      else
		{
		  std::__merge_sort_with_buffer(__first, __middle, __buffer);
		  std::__merge_sort_with_buffer(__middle, __last, __buffer);
		}
	      std::__merge_adaptive(__first, __middle, __last,
				    _Distance(__middle - __first),
				    _Distance(__last - __middle),
				    __buffer, __buffer_size);
	    }
	
	  template<typename _RandomAccessIterator, typename _Pointer,
		   typename _Distance, typename _Compare>
	    void
	    __stable_sort_adaptive(_RandomAccessIterator __first,
				   _RandomAccessIterator __last,
	                           _Pointer __buffer, _Distance __buffer_size,
	                           _Compare __comp)
	    {
	      const _Distance __len = (__last - __first + 1) / 2;
	      const _RandomAccessIterator __middle = __first + __len;
	      if (__len > __buffer_size)
		{
		  std::__stable_sort_adaptive(__first, __middle, __buffer,
					      __buffer_size, __comp);
		  std::__stable_sort_adaptive(__middle, __last, __buffer,
					      __buffer_size, __comp);
		}
	      else
		{
		  std::__merge_sort_with_buffer(__first, __middle, __buffer, __comp);
		  std::__merge_sort_with_buffer(__middle, __last, __buffer, __comp);
		}
	      std::__merge_adaptive(__first, __middle, __last,
				    _Distance(__middle - __first),
				    _Distance(__last - __middle),
				    __buffer, __buffer_size,
				    __comp);
	    }
	
	  /// This is a helper function for the stable sorting routines.
	  template<typename _RandomAccessIterator>
	    void
	    __inplace_stable_sort(_RandomAccessIterator __first,
				  _RandomAccessIterator __last)
	    {
	      if (__last - __first < 15)
		{
		  std::__insertion_sort(__first, __last);
		  return;
		}
	      _RandomAccessIterator __middle = __first + (__last - __first) / 2;
	      std::__inplace_stable_sort(__first, __middle);
	      std::__inplace_stable_sort(__middle, __last);
	      std::__merge_without_buffer(__first, __middle, __last,
					  __middle - __first,
					  __last - __middle);
	    }
	
	  /// This is a helper function for the stable sorting routines.
	  template<typename _RandomAccessIterator, typename _Compare>
	    void
	    __inplace_stable_sort(_RandomAccessIterator __first,
				  _RandomAccessIterator __last, _Compare __comp)
	    {
	      if (__last - __first < 15)
		{
		  std::__insertion_sort(__first, __last, __comp);
		  return;
		}
	      _RandomAccessIterator __middle = __first + (__last - __first) / 2;
	      std::__inplace_stable_sort(__first, __middle, __comp);
	      std::__inplace_stable_sort(__middle, __last, __comp);
	      std::__merge_without_buffer(__first, __middle, __last,
					  __middle - __first,
					  __last - __middle,
					  __comp);
	    }
	
	  // stable_sort
	
	  // Set algorithms: includes, set_union, set_intersection, set_difference,
	  // set_symmetric_difference.  All of these algorithms have the precondition
	  // that their input ranges are sorted and the postcondition that their output
	  // ranges are sorted.
	
	  /**
	   *  @brief Determines whether all elements of a sequence exists in a range.
	   *  @param  __first1  Start of search range.
	   *  @param  __last1   End of search range.
	   *  @param  __first2  Start of sequence
	   *  @param  __last2   End of sequence.
	   *  @return  True if each element in [__first2,__last2) is contained in order
	   *  within [__first1,__last1).  False otherwise.
	   *  @ingroup set_algorithms
	   *
	   *  This operation expects both [__first1,__last1) and
	   *  [__first2,__last2) to be sorted.  Searches for the presence of
	   *  each element in [__first2,__last2) within [__first1,__last1).
	   *  The iterators over each range only move forward, so this is a
	   *  linear algorithm.  If an element in [__first2,__last2) is not
	   *  found before the search iterator reaches @p __last2, false is
	   *  returned.
	  */
	  template<typename _InputIterator1, typename _InputIterator2>
	    bool
	    includes(_InputIterator1 __first1, _InputIterator1 __last1,
		     _InputIterator2 __first2, _InputIterator2 __last2)
	    {
	      typedef typename iterator_traits<_InputIterator1>::value_type
		_ValueType1;
	      typedef typename iterator_traits<_InputIterator2>::value_type
		_ValueType2;
	
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
	      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)
	      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)
	      __glibcxx_requires_sorted_set(__first1, __last1, __first2);
	      __glibcxx_requires_sorted_set(__first2, __last2, __first1);
	
	      while (__first1 != __last1 && __first2 != __last2)
		if (*__first2 < *__first1)
		  return false;
		else if(*__first1 < *__first2)
		  ++__first1;
		else
		  ++__first1, ++__first2;
	
	      return __first2 == __last2;
	    }
	
	  /**
	   *  @brief Determines whether all elements of a sequence exists in a range
	   *  using comparison.
	   *  @ingroup set_algorithms
	   *  @param  __first1  Start of search range.
	   *  @param  __last1   End of search range.
	   *  @param  __first2  Start of sequence
	   *  @param  __last2   End of sequence.
	   *  @param  __comp    Comparison function to use.
	   *  @return True if each element in [__first2,__last2) is contained
	   *  in order within [__first1,__last1) according to comp.  False
	   *  otherwise.  @ingroup set_algorithms
	   *
	   *  This operation expects both [__first1,__last1) and
	   *  [__first2,__last2) to be sorted.  Searches for the presence of
	   *  each element in [__first2,__last2) within [__first1,__last1),
	   *  using comp to decide.  The iterators over each range only move
	   *  forward, so this is a linear algorithm.  If an element in
	   *  [__first2,__last2) is not found before the search iterator
	   *  reaches @p __last2, false is returned.
	  */
	  template<typename _InputIterator1, typename _InputIterator2,
		   typename _Compare>
	    bool
	    includes(_InputIterator1 __first1, _InputIterator1 __last1,
		     _InputIterator2 __first2, _InputIterator2 __last2,
		     _Compare __comp)
	    {
	      typedef typename iterator_traits<_InputIterator1>::value_type
		_ValueType1;
	      typedef typename iterator_traits<_InputIterator2>::value_type
		_ValueType2;
	
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
					  _ValueType1, _ValueType2>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
					  _ValueType2, _ValueType1>)
	      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);
	      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);
	
	      while (__first1 != __last1 && __first2 != __last2)
		if (__comp(*__first2, *__first1))
		  return false;
		else if(__comp(*__first1, *__first2))
		  ++__first1;
		else
		  ++__first1, ++__first2;
	
	      return __first2 == __last2;
	    }
	
	  // nth_element
	  // merge
	  // set_difference
	  // set_intersection
	  // set_union
	  // stable_sort
	  // set_symmetric_difference
	  // min_element
	  // max_element
	
	  /**
	   *  @brief  Permute range into the next @e dictionary ordering.
	   *  @ingroup sorting_algorithms
	   *  @param  __first  Start of range.
	   *  @param  __last   End of range.
	   *  @return  False if wrapped to first permutation, true otherwise.
	   *
	   *  Treats all permutations of the range as a set of @e dictionary sorted
	   *  sequences.  Permutes the current sequence into the next one of this set.
	   *  Returns true if there are more sequences to generate.  If the sequence
	   *  is the largest of the set, the smallest is generated and false returned.
	  */
	  template<typename _BidirectionalIterator>
	    bool
	    next_permutation(_BidirectionalIterator __first,
			     _BidirectionalIterator __last)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_BidirectionalIteratorConcept<
					  _BidirectionalIterator>)
	      __glibcxx_function_requires(_LessThanComparableConcept<
		    typename iterator_traits<_BidirectionalIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first == __last)
		return false;
	      _BidirectionalIterator __i = __first;
	      ++__i;
	      if (__i == __last)
		return false;
	      __i = __last;
	      --__i;
	
	      for(;;)
		{
		  _BidirectionalIterator __ii = __i;
		  --__i;
		  if (*__i < *__ii)
		    {
		      _BidirectionalIterator __j = __last;
		      while (!(*__i < *--__j))
			{}
		      std::iter_swap(__i, __j);
		      std::reverse(__ii, __last);
		      return true;
		    }
		  if (__i == __first)
		    {
		      std::reverse(__first, __last);
		      return false;
		    }
		}
	    }
	
	  /**
	   *  @brief  Permute range into the next @e dictionary ordering using
	   *          comparison functor.
	   *  @ingroup sorting_algorithms
	   *  @param  __first  Start of range.
	   *  @param  __last   End of range.
	   *  @param  __comp   A comparison functor.
	   *  @return  False if wrapped to first permutation, true otherwise.
	   *
	   *  Treats all permutations of the range [__first,__last) as a set of
	   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current
	   *  sequence into the next one of this set.  Returns true if there are more
	   *  sequences to generate.  If the sequence is the largest of the set, the
	   *  smallest is generated and false returned.
	  */
	  template<typename _BidirectionalIterator, typename _Compare>
	    bool
	    next_permutation(_BidirectionalIterator __first,
			     _BidirectionalIterator __last, _Compare __comp)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_BidirectionalIteratorConcept<
					  _BidirectionalIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
		    typename iterator_traits<_BidirectionalIterator>::value_type,
		    typename iterator_traits<_BidirectionalIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first == __last)
		return false;
	      _BidirectionalIterator __i = __first;
	      ++__i;
	      if (__i == __last)
		return false;
	      __i = __last;
	      --__i;
	
	      for(;;)
		{
		  _BidirectionalIterator __ii = __i;
		  --__i;
		  if (__comp(*__i, *__ii))
		    {
		      _BidirectionalIterator __j = __last;
		      while (!bool(__comp(*__i, *--__j)))
			{}
		      std::iter_swap(__i, __j);
		      std::reverse(__ii, __last);
		      return true;
		    }
		  if (__i == __first)
		    {
		      std::reverse(__first, __last);
		      return false;
		    }
		}
	    }
	
	  /**
	   *  @brief  Permute range into the previous @e dictionary ordering.
	   *  @ingroup sorting_algorithms
	   *  @param  __first  Start of range.
	   *  @param  __last   End of range.
	   *  @return  False if wrapped to last permutation, true otherwise.
	   *
	   *  Treats all permutations of the range as a set of @e dictionary sorted
	   *  sequences.  Permutes the current sequence into the previous one of this
	   *  set.  Returns true if there are more sequences to generate.  If the
	   *  sequence is the smallest of the set, the largest is generated and false
	   *  returned.
	  */
	  template<typename _BidirectionalIterator>
	    bool
	    prev_permutation(_BidirectionalIterator __first,
			     _BidirectionalIterator __last)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_BidirectionalIteratorConcept<
					  _BidirectionalIterator>)
	      __glibcxx_function_requires(_LessThanComparableConcept<
		    typename iterator_traits<_BidirectionalIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first == __last)
		return false;
	      _BidirectionalIterator __i = __first;
	      ++__i;
	      if (__i == __last)
		return false;
	      __i = __last;
	      --__i;
	
	      for(;;)
		{
		  _BidirectionalIterator __ii = __i;
		  --__i;
		  if (*__ii < *__i)
		    {
		      _BidirectionalIterator __j = __last;
		      while (!(*--__j < *__i))
			{}
		      std::iter_swap(__i, __j);
		      std::reverse(__ii, __last);
		      return true;
		    }
		  if (__i == __first)
		    {
		      std::reverse(__first, __last);
		      return false;
		    }
		}
	    }
	
	  /**
	   *  @brief  Permute range into the previous @e dictionary ordering using
	   *          comparison functor.
	   *  @ingroup sorting_algorithms
	   *  @param  __first  Start of range.
	   *  @param  __last   End of range.
	   *  @param  __comp   A comparison functor.
	   *  @return  False if wrapped to last permutation, true otherwise.
	   *
	   *  Treats all permutations of the range [__first,__last) as a set of
	   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current
	   *  sequence into the previous one of this set.  Returns true if there are
	   *  more sequences to generate.  If the sequence is the smallest of the set,
	   *  the largest is generated and false returned.
	  */
	  template<typename _BidirectionalIterator, typename _Compare>
	    bool
	    prev_permutation(_BidirectionalIterator __first,
			     _BidirectionalIterator __last, _Compare __comp)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_BidirectionalIteratorConcept<
					  _BidirectionalIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
		    typename iterator_traits<_BidirectionalIterator>::value_type,
		    typename iterator_traits<_BidirectionalIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first == __last)
		return false;
	      _BidirectionalIterator __i = __first;
	      ++__i;
	      if (__i == __last)
		return false;
	      __i = __last;
	      --__i;
	
	      for(;;)
		{
		  _BidirectionalIterator __ii = __i;
		  --__i;
		  if (__comp(*__ii, *__i))
		    {
		      _BidirectionalIterator __j = __last;
		      while (!bool(__comp(*--__j, *__i)))
			{}
		      std::iter_swap(__i, __j);
		      std::reverse(__ii, __last);
		      return true;
		    }
		  if (__i == __first)
		    {
		      std::reverse(__first, __last);
		      return false;
		    }
		}
	    }
	
	  // replace
	  // replace_if
	
	  /**
	   *  @brief Copy a sequence, replacing each element of one value with another
	   *         value.
	   *  @param  __first      An input iterator.
	   *  @param  __last       An input iterator.
	   *  @param  __result     An output iterator.
	   *  @param  __old_value  The value to be replaced.
	   *  @param  __new_value  The replacement value.
	   *  @return   The end of the output sequence, @p result+(last-first).
	   *
	   *  Copies each element in the input range @p [__first,__last) to the
	   *  output range @p [__result,__result+(__last-__first)) replacing elements
	   *  equal to @p __old_value with @p __new_value.
	  */
	  template<typename _InputIterator, typename _OutputIterator, typename _Tp>
	    _OutputIterator
	    replace_copy(_InputIterator __first, _InputIterator __last,
			 _OutputIterator __result,
			 const _Tp& __old_value, const _Tp& __new_value)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_function_requires(_EqualOpConcept<
		    typename iterator_traits<_InputIterator>::value_type, _Tp>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      for (; __first != __last; ++__first, ++__result)
		if (*__first == __old_value)
		  *__result = __new_value;
		else
		  *__result = *__first;
	      return __result;
	    }
	
	  /**
	   *  @brief Copy a sequence, replacing each value for which a predicate
	   *         returns true with another value.
	   *  @ingroup mutating_algorithms
	   *  @param  __first      An input iterator.
	   *  @param  __last       An input iterator.
	   *  @param  __result     An output iterator.
	   *  @param  __pred       A predicate.
	   *  @param  __new_value  The replacement value.
	   *  @return   The end of the output sequence, @p __result+(__last-__first).
	   *
	   *  Copies each element in the range @p [__first,__last) to the range
	   *  @p [__result,__result+(__last-__first)) replacing elements for which
	   *  @p __pred returns true with @p __new_value.
	  */
	  template<typename _InputIterator, typename _OutputIterator,
		   typename _Predicate, typename _Tp>
	    _OutputIterator
	    replace_copy_if(_InputIterator __first, _InputIterator __last,
			    _OutputIterator __result,
			    _Predicate __pred, const _Tp& __new_value)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      for (; __first != __last; ++__first, ++__result)
		if (__pred(*__first))
		  *__result = __new_value;
		else
		  *__result = *__first;
	      return __result;
	    }
	
	#if __cplusplus >= 201103L
	  /**
	   *  @brief  Determines whether the elements of a sequence are sorted.
	   *  @ingroup sorting_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @return  True if the elements are sorted, false otherwise.
	  */
	  template<typename _ForwardIterator>
	    inline bool
	    is_sorted(_ForwardIterator __first, _ForwardIterator __last)
	    { return std::is_sorted_until(__first, __last) == __last; }
	
	  /**
	   *  @brief  Determines whether the elements of a sequence are sorted
	   *          according to a comparison functor.
	   *  @ingroup sorting_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __comp    A comparison functor.
	   *  @return  True if the elements are sorted, false otherwise.
	  */
	  template<typename _ForwardIterator, typename _Compare>
	    inline bool
	    is_sorted(_ForwardIterator __first, _ForwardIterator __last,
		      _Compare __comp)
	    { return std::is_sorted_until(__first, __last, __comp) == __last; }
	
	  /**
	   *  @brief  Determines the end of a sorted sequence.
	   *  @ingroup sorting_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @return  An iterator pointing to the last iterator i in [__first, __last)
	   *           for which the range [__first, i) is sorted.
	  */
	  template<typename _ForwardIterator>
	    _ForwardIterator
	    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_LessThanComparableConcept<
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first == __last)
		return __last;
	
	      _ForwardIterator __next = __first;
	      for (++__next; __next != __last; __first = __next, ++__next)
		if (*__next < *__first)
		  return __next;
	      return __next;
	    }
	
	  /**
	   *  @brief  Determines the end of a sorted sequence using comparison functor.
	   *  @ingroup sorting_algorithms
	   *  @param  __first   An iterator.
	   *  @param  __last    Another iterator.
	   *  @param  __comp    A comparison functor.
	   *  @return  An iterator pointing to the last iterator i in [__first, __last)
	   *           for which the range [__first, i) is sorted.
	  */
	  template<typename _ForwardIterator, typename _Compare>
	    _ForwardIterator
	    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last,
			    _Compare __comp)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
		    typename iterator_traits<_ForwardIterator>::value_type,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first == __last)
		return __last;
	
	      _ForwardIterator __next = __first;
	      for (++__next; __next != __last; __first = __next, ++__next)
		if (__comp(*__next, *__first))
		  return __next;
	      return __next;
	    }
	
	  /**
	   *  @brief  Determines min and max at once as an ordered pair.
	   *  @ingroup sorting_algorithms
	   *  @param  __a  A thing of arbitrary type.
	   *  @param  __b  Another thing of arbitrary type.
	   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
	   *  __b) otherwise.
	  */
	  template<typename _Tp>
	    inline pair<const _Tp&, const _Tp&>
	    minmax(const _Tp& __a, const _Tp& __b)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
	
	      return __b < __a ? pair<const _Tp&, const _Tp&>(__b, __a)
		               : pair<const _Tp&, const _Tp&>(__a, __b);
	    }
	
	  /**
	   *  @brief  Determines min and max at once as an ordered pair.
	   *  @ingroup sorting_algorithms
	   *  @param  __a  A thing of arbitrary type.
	   *  @param  __b  Another thing of arbitrary type.
	   *  @param  __comp  A @link comparison_functors comparison functor @endlink.
	   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,
	   *  __b) otherwise.
	  */
	  template<typename _Tp, typename _Compare>
	    inline pair<const _Tp&, const _Tp&>
	    minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
	    {
	      return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a)
		                      : pair<const _Tp&, const _Tp&>(__a, __b);
	    }
	
	  /**
	   *  @brief  Return a pair of iterators pointing to the minimum and maximum
	   *          elements in a range.
	   *  @ingroup sorting_algorithms
	   *  @param  __first  Start of range.
	   *  @param  __last   End of range.
	   *  @return  make_pair(m, M), where m is the first iterator i in 
	   *           [__first, __last) such that no other element in the range is
	   *           smaller, and where M is the last iterator i in [__first, __last)
	   *           such that no other element in the range is larger.
	  */
	  template<typename _ForwardIterator>
	    pair<_ForwardIterator, _ForwardIterator>
	    minmax_element(_ForwardIterator __first, _ForwardIterator __last)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_LessThanComparableConcept<
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      _ForwardIterator __next = __first;
	      if (__first == __last
		  || ++__next == __last)
		return std::make_pair(__first, __first);
	
	      _ForwardIterator __min, __max;
	      if (*__next < *__first)
		{
		  __min = __next;
		  __max = __first;
		}
	      else
		{
		  __min = __first;
		  __max = __next;
		}
	
	      __first = __next;
	      ++__first;
	
	      while (__first != __last)
		{
		  __next = __first;
		  if (++__next == __last)
		    {
		      if (*__first < *__min)
			__min = __first;
		      else if (!(*__first < *__max))
			__max = __first;
		      break;
		    }
	
		  if (*__next < *__first)
		    {
		      if (*__next < *__min)
			__min = __next;
		      if (!(*__first < *__max))
			__max = __first;
		    }
		  else
		    {
		      if (*__first < *__min)
			__min = __first;
		      if (!(*__next < *__max))
			__max = __next;
		    }
	
		  __first = __next;
		  ++__first;
		}
	
	      return std::make_pair(__min, __max);
	    }
	
	  /**
	   *  @brief  Return a pair of iterators pointing to the minimum and maximum
	   *          elements in a range.
	   *  @ingroup sorting_algorithms
	   *  @param  __first  Start of range.
	   *  @param  __last   End of range.
	   *  @param  __comp   Comparison functor.
	   *  @return  make_pair(m, M), where m is the first iterator i in 
	   *           [__first, __last) such that no other element in the range is
	   *           smaller, and where M is the last iterator i in [__first, __last)
	   *           such that no other element in the range is larger.
	  */
	  template<typename _ForwardIterator, typename _Compare>
	    pair<_ForwardIterator, _ForwardIterator>
	    minmax_element(_ForwardIterator __first, _ForwardIterator __last,
			   _Compare __comp)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,
		    typename iterator_traits<_ForwardIterator>::value_type,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      _ForwardIterator __next = __first;
	      if (__first == __last
		  || ++__next == __last)
		return std::make_pair(__first, __first);
	
	      _ForwardIterator __min, __max;
	      if (__comp(*__next, *__first))
		{
		  __min = __next;
		  __max = __first;
		}
	      else
		{
		  __min = __first;
		  __max = __next;
		}
	
	      __first = __next;
	      ++__first;
	
	      while (__first != __last)
		{
		  __next = __first;
		  if (++__next == __last)
		    {
		      if (__comp(*__first, *__min))
			__min = __first;
		      else if (!__comp(*__first, *__max))
			__max = __first;
		      break;
		    }
	
		  if (__comp(*__next, *__first))
		    {
		      if (__comp(*__next, *__min))
			__min = __next;
		      if (!__comp(*__first, *__max))
			__max = __first;
		    }
		  else
		    {
		      if (__comp(*__first, *__min))
			__min = __first;
		      if (!__comp(*__next, *__max))
			__max = __next;
		    }
	
		  __first = __next;
		  ++__first;
		}
	
	      return std::make_pair(__min, __max);
	    }
	
	  // N2722 + DR 915.
	  template<typename _Tp>
	    inline _Tp
	    min(initializer_list<_Tp> __l)
	    { return *std::min_element(__l.begin(), __l.end()); }
	
	  template<typename _Tp, typename _Compare>
	    inline _Tp
	    min(initializer_list<_Tp> __l, _Compare __comp)
	    { return *std::min_element(__l.begin(), __l.end(), __comp); }
	
	  template<typename _Tp>
	    inline _Tp
	    max(initializer_list<_Tp> __l)
	    { return *std::max_element(__l.begin(), __l.end()); }
	
	  template<typename _Tp, typename _Compare>
	    inline _Tp
	    max(initializer_list<_Tp> __l, _Compare __comp)
	    { return *std::max_element(__l.begin(), __l.end(), __comp); }
	
	  template<typename _Tp>
	    inline pair<_Tp, _Tp>
	    minmax(initializer_list<_Tp> __l)
	    {
	      pair<const _Tp*, const _Tp*> __p =
		std::minmax_element(__l.begin(), __l.end());
	      return std::make_pair(*__p.first, *__p.second);
	    }
	
	  template<typename _Tp, typename _Compare>
	    inline pair<_Tp, _Tp>
	    minmax(initializer_list<_Tp> __l, _Compare __comp)
	    {
	      pair<const _Tp*, const _Tp*> __p =
		std::minmax_element(__l.begin(), __l.end(), __comp);
	      return std::make_pair(*__p.first, *__p.second);
	    }
	
	  /**
	   *  @brief  Checks whether a permutaion of the second sequence is equal
	   *          to the first sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first1  Start of first range.
	   *  @param  __last1   End of first range.
	   *  @param  __first2  Start of second range.
	   *  @return true if there exists a permutation of the elements in the range
	   *          [__first2, __first2 + (__last1 - __first1)), beginning with 
	   *          ForwardIterator2 begin, such that equal(__first1, __last1, begin)
	   *          returns true; otherwise, returns false.
	  */
	  template<typename _ForwardIterator1, typename _ForwardIterator2>
	    bool
	    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
			   _ForwardIterator2 __first2)
	    {
	      // Efficiently compare identical prefixes:  O(N) if sequences
	      // have the same elements in the same order.
	      for (; __first1 != __last1; ++__first1, ++__first2)
		if (!(*__first1 == *__first2))
		  break;
	
	      if (__first1 == __last1)
		return true;
	
	      // Establish __last2 assuming equal ranges by iterating over the
	      // rest of the list.
	      _ForwardIterator2 __last2 = __first2;
	      std::advance(__last2, std::distance(__first1, __last1));
	      for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
		{
		  if (__scan != _GLIBCXX_STD_A::find(__first1, __scan, *__scan))
		    continue; // We've seen this one before.
	
		  auto __matches = std::count(__first2, __last2, *__scan);
		  if (0 == __matches
		      || std::count(__scan, __last1, *__scan) != __matches)
		    return false;
		}
	      return true;
	    }
	
	  /**
	   *  @brief  Checks whether a permutation of the second sequence is equal
	   *          to the first sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first1  Start of first range.
	   *  @param  __last1   End of first range.
	   *  @param  __first2  Start of second range.
	   *  @param  __pred    A binary predicate.
	   *  @return true if there exists a permutation of the elements in
	   *          the range [__first2, __first2 + (__last1 - __first1)),
	   *          beginning with ForwardIterator2 begin, such that
	   *          equal(__first1, __last1, __begin, __pred) returns true;
	   *          otherwise, returns false.
	  */
	  template<typename _ForwardIterator1, typename _ForwardIterator2,
		   typename _BinaryPredicate>
	    bool
	    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
			   _ForwardIterator2 __first2, _BinaryPredicate __pred)
	    {
	      // Efficiently compare identical prefixes:  O(N) if sequences
	      // have the same elements in the same order.
	      for (; __first1 != __last1; ++__first1, ++__first2)
		if (!bool(__pred(*__first1, *__first2)))
		  break;
	
	      if (__first1 == __last1)
		return true;
	
	      // Establish __last2 assuming equal ranges by iterating over the
	      // rest of the list.
	      _ForwardIterator2 __last2 = __first2;
	      std::advance(__last2, std::distance(__first1, __last1));
	      for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan)
		{
		  using std::placeholders::_1;
	
		  if (__scan != _GLIBCXX_STD_A::find_if(__first1, __scan,
							std::bind(__pred, _1, *__scan)))
		    continue; // We've seen this one before.
		  
		  auto __matches = std::count_if(__first2, __last2,
						 std::bind(__pred, _1, *__scan));
		  if (0 == __matches
		      || std::count_if(__scan, __last1,
				       std::bind(__pred, _1, *__scan)) != __matches)
		    return false;
		}
	      return true;
	    }
	
	#ifdef _GLIBCXX_USE_C99_STDINT_TR1
	  /**
	   *  @brief Shuffle the elements of a sequence using a uniform random
	   *         number generator.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   A forward iterator.
	   *  @param  __last    A forward iterator.
	   *  @param  __g       A UniformRandomNumberGenerator (26.5.1.3).
	   *  @return  Nothing.
	   *
	   *  Reorders the elements in the range @p [__first,__last) using @p __g to
	   *  provide random numbers.
	  */
	  template<typename _RandomAccessIterator,
		   typename _UniformRandomNumberGenerator>
	    void
	    shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
		    _UniformRandomNumberGenerator&& __g)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
		    _RandomAccessIterator>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first == __last)
		return;
	
	      typedef typename iterator_traits<_RandomAccessIterator>::difference_type
		_DistanceType;
	
	      typedef typename std::make_unsigned<_DistanceType>::type __ud_type;
	      typedef typename std::uniform_int_distribution<__ud_type> __distr_type;
	      typedef typename __distr_type::param_type __p_type;
	      __distr_type __d;
	
	      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)
		std::iter_swap(__i, __first + __d(__g, __p_type(0, __i - __first)));
	    }
	#endif
	
	#endif // C++11
	
	_GLIBCXX_END_NAMESPACE_VERSION
	
	_GLIBCXX_BEGIN_NAMESPACE_ALGO
	
	  /**
	   *  @brief Apply a function to every element of a sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first  An input iterator.
	   *  @param  __last   An input iterator.
	   *  @param  __f      A unary function object.
	   *  @return   @p __f (std::move(@p __f) in C++0x).
	   *
	   *  Applies the function object @p __f to each element in the range
	   *  @p [first,last).  @p __f must not modify the order of the sequence.
	   *  If @p __f has a return value it is ignored.
	  */
	  template<typename _InputIterator, typename _Function>
	    _Function
	    for_each(_InputIterator __first, _InputIterator __last, _Function __f)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_requires_valid_range(__first, __last);
	      for (; __first != __last; ++__first)
		__f(*__first);
	      return _GLIBCXX_MOVE(__f);
	    }
	
	  /**
	   *  @brief Find the first occurrence of a value in a sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first  An input iterator.
	   *  @param  __last   An input iterator.
	   *  @param  __val    The value to find.
	   *  @return   The first iterator @c i in the range @p [__first,__last)
	   *  such that @c *i == @p __val, or @p __last if no such iterator exists.
	  */
	  template<typename _InputIterator, typename _Tp>
	    inline _InputIterator
	    find(_InputIterator __first, _InputIterator __last,
		 const _Tp& __val)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_EqualOpConcept<
			typename iterator_traits<_InputIterator>::value_type, _Tp>)
	      __glibcxx_requires_valid_range(__first, __last);
	      return std::__find(__first, __last, __val,
			         std::__iterator_category(__first));
	    }
	
	  /**
	   *  @brief Find the first element in a sequence for which a
	   *         predicate is true.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first  An input iterator.
	   *  @param  __last   An input iterator.
	   *  @param  __pred   A predicate.
	   *  @return   The first iterator @c i in the range @p [__first,__last)
	   *  such that @p __pred(*i) is true, or @p __last if no such iterator exists.
	  */
	  template<typename _InputIterator, typename _Predicate>
	    inline _InputIterator
	    find_if(_InputIterator __first, _InputIterator __last,
		    _Predicate __pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		      typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	      return std::__find_if(__first, __last, __pred,
				    std::__iterator_category(__first));
	    }
	
	  /**
	   *  @brief  Find element from a set in a sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first1  Start of range to search.
	   *  @param  __last1   End of range to search.
	   *  @param  __first2  Start of match candidates.
	   *  @param  __last2   End of match candidates.
	   *  @return   The first iterator @c i in the range
	   *  @p [__first1,__last1) such that @c *i == @p *(i2) such that i2 is an
	   *  iterator in [__first2,__last2), or @p __last1 if no such iterator exists.
	   *
	   *  Searches the range @p [__first1,__last1) for an element that is
	   *  equal to some element in the range [__first2,__last2).  If
	   *  found, returns an iterator in the range [__first1,__last1),
	   *  otherwise returns @p __last1.
	  */
	  template<typename _InputIterator, typename _ForwardIterator>
	    _InputIterator
	    find_first_of(_InputIterator __first1, _InputIterator __last1,
			  _ForwardIterator __first2, _ForwardIterator __last2)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_EqualOpConcept<
		    typename iterator_traits<_InputIterator>::value_type,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first1, __last1);
	      __glibcxx_requires_valid_range(__first2, __last2);
	
	      for (; __first1 != __last1; ++__first1)
		for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
		  if (*__first1 == *__iter)
		    return __first1;
	      return __last1;
	    }
	
	  /**
	   *  @brief  Find element from a set in a sequence using a predicate.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first1  Start of range to search.
	   *  @param  __last1   End of range to search.
	   *  @param  __first2  Start of match candidates.
	   *  @param  __last2   End of match candidates.
	   *  @param  __comp    Predicate to use.
	   *  @return   The first iterator @c i in the range
	   *  @p [__first1,__last1) such that @c comp(*i, @p *(i2)) is true
	   *  and i2 is an iterator in [__first2,__last2), or @p __last1 if no
	   *  such iterator exists.
	   *
	
	   *  Searches the range @p [__first1,__last1) for an element that is
	   *  equal to some element in the range [__first2,__last2).  If
	   *  found, returns an iterator in the range [__first1,__last1),
	   *  otherwise returns @p __last1.
	  */
	  template<typename _InputIterator, typename _ForwardIterator,
		   typename _BinaryPredicate>
	    _InputIterator
	    find_first_of(_InputIterator __first1, _InputIterator __last1,
			  _ForwardIterator __first2, _ForwardIterator __last2,
			  _BinaryPredicate __comp)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
		    typename iterator_traits<_InputIterator>::value_type,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first1, __last1);
	      __glibcxx_requires_valid_range(__first2, __last2);
	
	      for (; __first1 != __last1; ++__first1)
		for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)
		  if (__comp(*__first1, *__iter))
		    return __first1;
	      return __last1;
	    }
	
	  /**
	   *  @brief Find two adjacent values in a sequence that are equal.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first  A forward iterator.
	   *  @param  __last   A forward iterator.
	   *  @return   The first iterator @c i such that @c i and @c i+1 are both
	   *  valid iterators in @p [__first,__last) and such that @c *i == @c *(i+1),
	   *  or @p __last if no such iterator exists.
	  */
	  template<typename _ForwardIterator>
	    _ForwardIterator
	    adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_EqualityComparableConcept<
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	      if (__first == __last)
		return __last;
	      _ForwardIterator __next = __first;
	      while(++__next != __last)
		{
		  if (*__first == *__next)
		    return __first;
		  __first = __next;
		}
	      return __last;
	    }
	
	  /**
	   *  @brief Find two adjacent values in a sequence using a predicate.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first         A forward iterator.
	   *  @param  __last          A forward iterator.
	   *  @param  __binary_pred   A binary predicate.
	   *  @return   The first iterator @c i such that @c i and @c i+1 are both
	   *  valid iterators in @p [__first,__last) and such that
	   *  @p __binary_pred(*i,*(i+1)) is true, or @p __last if no such iterator
	   *  exists.
	  */
	  template<typename _ForwardIterator, typename _BinaryPredicate>
	    _ForwardIterator
	    adjacent_find(_ForwardIterator __first, _ForwardIterator __last,
			  _BinaryPredicate __binary_pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
		    typename iterator_traits<_ForwardIterator>::value_type,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	      if (__first == __last)
		return __last;
	      _ForwardIterator __next = __first;
	      while(++__next != __last)
		{
		  if (__binary_pred(*__first, *__next))
		    return __first;
		  __first = __next;
		}
	      return __last;
	    }
	
	  /**
	   *  @brief Count the number of copies of a value in a sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first  An input iterator.
	   *  @param  __last   An input iterator.
	   *  @param  __value  The value to be counted.
	   *  @return   The number of iterators @c i in the range @p [__first,__last)
	   *  for which @c *i == @p __value
	  */
	  template<typename _InputIterator, typename _Tp>
	    typename iterator_traits<_InputIterator>::difference_type
	    count(_InputIterator __first, _InputIterator __last, const _Tp& __value)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_EqualOpConcept<
		typename iterator_traits<_InputIterator>::value_type, _Tp>)
	      __glibcxx_requires_valid_range(__first, __last);
	      typename iterator_traits<_InputIterator>::difference_type __n = 0;
	      for (; __first != __last; ++__first)
		if (*__first == __value)
		  ++__n;
	      return __n;
	    }
	
	  /**
	   *  @brief Count the elements of a sequence for which a predicate is true.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first  An input iterator.
	   *  @param  __last   An input iterator.
	   *  @param  __pred   A predicate.
	   *  @return   The number of iterators @c i in the range @p [__first,__last)
	   *  for which @p __pred(*i) is true.
	  */
	  template<typename _InputIterator, typename _Predicate>
	    typename iterator_traits<_InputIterator>::difference_type
	    count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	      typename iterator_traits<_InputIterator>::difference_type __n = 0;
	      for (; __first != __last; ++__first)
		if (__pred(*__first))
		  ++__n;
	      return __n;
	    }
	
	  /**
	   *  @brief Search a sequence for a matching sub-sequence.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first1  A forward iterator.
	   *  @param  __last1   A forward iterator.
	   *  @param  __first2  A forward iterator.
	   *  @param  __last2   A forward iterator.
	   *  @return The first iterator @c i in the range @p
	   *  [__first1,__last1-(__last2-__first2)) such that @c *(i+N) == @p
	   *  *(__first2+N) for each @c N in the range @p
	   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.
	   *
	   *  Searches the range @p [__first1,__last1) for a sub-sequence that
	   *  compares equal value-by-value with the sequence given by @p
	   *  [__first2,__last2) and returns an iterator to the first element
	   *  of the sub-sequence, or @p __last1 if the sub-sequence is not
	   *  found.
	   *
	   *  Because the sub-sequence must lie completely within the range @p
	   *  [__first1,__last1) it must start at a position less than @p
	   *  __last1-(__last2-__first2) where @p __last2-__first2 is the
	   *  length of the sub-sequence.
	   *
	   *  This means that the returned iterator @c i will be in the range
	   *  @p [__first1,__last1-(__last2-__first2))
	  */
	  template<typename _ForwardIterator1, typename _ForwardIterator2>
	    _ForwardIterator1
	    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		   _ForwardIterator2 __first2, _ForwardIterator2 __last2)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
	      __glibcxx_function_requires(_EqualOpConcept<
		    typename iterator_traits<_ForwardIterator1>::value_type,
		    typename iterator_traits<_ForwardIterator2>::value_type>)
	      __glibcxx_requires_valid_range(__first1, __last1);
	      __glibcxx_requires_valid_range(__first2, __last2);
	
	      // Test for empty ranges
	      if (__first1 == __last1 || __first2 == __last2)
		return __first1;
	
	      // Test for a pattern of length 1.
	      _ForwardIterator2 __p1(__first2);
	      if (++__p1 == __last2)
		return _GLIBCXX_STD_A::find(__first1, __last1, *__first2);
	
	      // General case.
	      _ForwardIterator2 __p;
	      _ForwardIterator1 __current = __first1;
	
	      for (;;)
		{
		  __first1 = _GLIBCXX_STD_A::find(__first1, __last1, *__first2);
		  if (__first1 == __last1)
		    return __last1;
	
		  __p = __p1;
		  __current = __first1;
		  if (++__current == __last1)
		    return __last1;
	
		  while (*__current == *__p)
		    {
		      if (++__p == __last2)
			return __first1;
		      if (++__current == __last1)
			return __last1;
		    }
		  ++__first1;
		}
	      return __first1;
	    }
	
	  /**
	   *  @brief Search a sequence for a matching sub-sequence using a predicate.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first1     A forward iterator.
	   *  @param  __last1      A forward iterator.
	   *  @param  __first2     A forward iterator.
	   *  @param  __last2      A forward iterator.
	   *  @param  __predicate  A binary predicate.
	   *  @return   The first iterator @c i in the range
	   *  @p [__first1,__last1-(__last2-__first2)) such that
	   *  @p __predicate(*(i+N),*(__first2+N)) is true for each @c N in the range
	   *  @p [0,__last2-__first2), or @p __last1 if no such iterator exists.
	   *
	   *  Searches the range @p [__first1,__last1) for a sub-sequence that
	   *  compares equal value-by-value with the sequence given by @p
	   *  [__first2,__last2), using @p __predicate to determine equality,
	   *  and returns an iterator to the first element of the
	   *  sub-sequence, or @p __last1 if no such iterator exists.
	   *
	   *  @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2)
	  */
	  template<typename _ForwardIterator1, typename _ForwardIterator2,
		   typename _BinaryPredicate>
	    _ForwardIterator1
	    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
		   _ForwardIterator2 __first2, _ForwardIterator2 __last2,
		   _BinaryPredicate  __predicate)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
		    typename iterator_traits<_ForwardIterator1>::value_type,
		    typename iterator_traits<_ForwardIterator2>::value_type>)
	      __glibcxx_requires_valid_range(__first1, __last1);
	      __glibcxx_requires_valid_range(__first2, __last2);
	
	      // Test for empty ranges
	      if (__first1 == __last1 || __first2 == __last2)
		return __first1;
	
	      // Test for a pattern of length 1.
	      _ForwardIterator2 __p1(__first2);
	      if (++__p1 == __last2)
		{
		  while (__first1 != __last1
			 && !bool(__predicate(*__first1, *__first2)))
		    ++__first1;
		  return __first1;
		}
	
	      // General case.
	      _ForwardIterator2 __p;
	      _ForwardIterator1 __current = __first1;
	
	      for (;;)
		{
		  while (__first1 != __last1
			 && !bool(__predicate(*__first1, *__first2)))
		    ++__first1;
		  if (__first1 == __last1)
		    return __last1;
	
		  __p = __p1;
		  __current = __first1;
		  if (++__current == __last1)
		    return __last1;
	
		  while (__predicate(*__current, *__p))
		    {
		      if (++__p == __last2)
			return __first1;
		      if (++__current == __last1)
			return __last1;
		    }
		  ++__first1;
		}
	      return __first1;
	    }
	
	
	  /**
	   *  @brief Search a sequence for a number of consecutive values.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first  A forward iterator.
	   *  @param  __last   A forward iterator.
	   *  @param  __count  The number of consecutive values.
	   *  @param  __val    The value to find.
	   *  @return The first iterator @c i in the range @p
	   *  [__first,__last-__count) such that @c *(i+N) == @p __val for
	   *  each @c N in the range @p [0,__count), or @p __last if no such
	   *  iterator exists.
	   *
	   *  Searches the range @p [__first,__last) for @p count consecutive elements
	   *  equal to @p __val.
	  */
	  template<typename _ForwardIterator, typename _Integer, typename _Tp>
	    _ForwardIterator
	    search_n(_ForwardIterator __first, _ForwardIterator __last,
		     _Integer __count, const _Tp& __val)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_EqualOpConcept<
		typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__count <= 0)
		return __first;
	      if (__count == 1)
		return _GLIBCXX_STD_A::find(__first, __last, __val);
	      return std::__search_n(__first, __last, __count, __val,
				     std::__iterator_category(__first));
	    }
	
	
	  /**
	   *  @brief Search a sequence for a number of consecutive values using a
	   *         predicate.
	   *  @ingroup non_mutating_algorithms
	   *  @param  __first        A forward iterator.
	   *  @param  __last         A forward iterator.
	   *  @param  __count        The number of consecutive values.
	   *  @param  __val          The value to find.
	   *  @param  __binary_pred  A binary predicate.
	   *  @return The first iterator @c i in the range @p
	   *  [__first,__last-__count) such that @p
	   *  __binary_pred(*(i+N),__val) is true for each @c N in the range
	   *  @p [0,__count), or @p __last if no such iterator exists.
	   *
	   *  Searches the range @p [__first,__last) for @p __count
	   *  consecutive elements for which the predicate returns true.
	  */
	  template<typename _ForwardIterator, typename _Integer, typename _Tp,
	           typename _BinaryPredicate>
	    _ForwardIterator
	    search_n(_ForwardIterator __first, _ForwardIterator __last,
		     _Integer __count, const _Tp& __val,
		     _BinaryPredicate __binary_pred)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,
		    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__count <= 0)
		return __first;
	      if (__count == 1)
		{
		  while (__first != __last && !bool(__binary_pred(*__first, __val)))
		    ++__first;
		  return __first;
		}
	      return std::__search_n(__first, __last, __count, __val, __binary_pred,
				     std::__iterator_category(__first));
	    }
	
	
	  /**
	   *  @brief Perform an operation on a sequence.
	   *  @ingroup mutating_algorithms
	   *  @param  __first     An input iterator.
	   *  @param  __last      An input iterator.
	   *  @param  __result    An output iterator.
	   *  @param  __unary_op  A unary operator.
	   *  @return   An output iterator equal to @p __result+(__last-__first).
	   *
	   *  Applies the operator to each element in the input range and assigns
	   *  the results to successive elements of the output sequence.
	   *  Evaluates @p *(__result+N)=unary_op(*(__first+N)) for each @c N in the
	   *  range @p [0,__last-__first).
	   *
	   *  @p unary_op must not alter its argument.
	  */
	  template<typename _InputIterator, typename _OutputIterator,
		   typename _UnaryOperation>
	    _OutputIterator
	    transform(_InputIterator __first, _InputIterator __last,
		      _OutputIterator __result, _UnaryOperation __unary_op)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	            // "the type returned by a _UnaryOperation"
	            __typeof__(__unary_op(*__first))>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      for (; __first != __last; ++__first, ++__result)
		*__result = __unary_op(*__first);
	      return __result;
	    }
	
	  /**
	   *  @brief Perform an operation on corresponding elements of two sequences.
	   *  @ingroup mutating_algorithms
	   *  @param  __first1     An input iterator.
	   *  @param  __last1      An input iterator.
	   *  @param  __first2     An input iterator.
	   *  @param  __result     An output iterator.
	   *  @param  __binary_op  A binary operator.
	   *  @return   An output iterator equal to @p result+(last-first).
	   *
	   *  Applies the operator to the corresponding elements in the two
	   *  input ranges and assigns the results to successive elements of the
	   *  output sequence.
	   *  Evaluates @p
	   *  *(__result+N)=__binary_op(*(__first1+N),*(__first2+N)) for each
	   *  @c N in the range @p [0,__last1-__first1).
	   *
	   *  @p binary_op must not alter either of its arguments.
	  */
	  template<typename _InputIterator1, typename _InputIterator2,
		   typename _OutputIterator, typename _BinaryOperation>
	    _OutputIterator
	    transform(_InputIterator1 __first1, _InputIterator1 __last1,
		      _InputIterator2 __first2, _OutputIterator __result,
		      _BinaryOperation __binary_op)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	            // "the type returned by a _BinaryOperation"
	            __typeof__(__binary_op(*__first1,*__first2))>)
	      __glibcxx_requires_valid_range(__first1, __last1);
	
	      for (; __first1 != __last1; ++__first1, ++__first2, ++__result)
		*__result = __binary_op(*__first1, *__first2);
	      return __result;
	    }
	
	  /**
	   *  @brief Replace each occurrence of one value in a sequence with another
	   *         value.
	   *  @ingroup mutating_algorithms
	   *  @param  __first      A forward iterator.
	   *  @param  __last       A forward iterator.
	   *  @param  __old_value  The value to be replaced.
	   *  @param  __new_value  The replacement value.
	   *  @return   replace() returns no value.
	   *
	   *  For each iterator @c i in the range @p [__first,__last) if @c *i ==
	   *  @p __old_value then the assignment @c *i = @p __new_value is performed.
	  */
	  template<typename _ForwardIterator, typename _Tp>
	    void
	    replace(_ForwardIterator __first, _ForwardIterator __last,
		    const _Tp& __old_value, const _Tp& __new_value)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
					  _ForwardIterator>)
	      __glibcxx_function_requires(_EqualOpConcept<
		    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)
	      __glibcxx_function_requires(_ConvertibleConcept<_Tp,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      for (; __first != __last; ++__first)
		if (*__first == __old_value)
		  *__first = __new_value;
	    }
	
	  /**
	   *  @brief Replace each value in a sequence for which a predicate returns
	   *         true with another value.
	   *  @ingroup mutating_algorithms
	   *  @param  __first      A forward iterator.
	   *  @param  __last       A forward iterator.
	   *  @param  __pred       A predicate.
	   *  @param  __new_value  The replacement value.
	   *  @return   replace_if() returns no value.
	   *
	   *  For each iterator @c i in the range @p [__first,__last) if @p __pred(*i)
	   *  is true then the assignment @c *i = @p __new_value is performed.
	  */
	  template<typename _ForwardIterator, typename _Predicate, typename _Tp>
	    void
	    replace_if(_ForwardIterator __first, _ForwardIterator __last,
		       _Predicate __pred, const _Tp& __new_value)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<
					  _ForwardIterator>)
	      __glibcxx_function_requires(_ConvertibleConcept<_Tp,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      for (; __first != __last; ++__first)
		if (__pred(*__first))
		  *__first = __new_value;
	    }
	
	  /**
	   *  @brief Assign the result of a function object to each value in a
	   *         sequence.
	   *  @ingroup mutating_algorithms
	   *  @param  __first  A forward iterator.
	   *  @param  __last   A forward iterator.
	   *  @param  __gen    A function object taking no arguments and returning
	   *                 std::iterator_traits<_ForwardIterator>::value_type
	   *  @return   generate() returns no value.
	   *
	   *  Performs the assignment @c *i = @p __gen() for each @c i in the range
	   *  @p [__first,__last).
	  */
	  template<typename _ForwardIterator, typename _Generator>
	    void
	    generate(_ForwardIterator __first, _ForwardIterator __last,
		     _Generator __gen)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
	      __glibcxx_function_requires(_GeneratorConcept<_Generator,
		    typename iterator_traits<_ForwardIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      for (; __first != __last; ++__first)
		*__first = __gen();
	    }
	
	  /**
	   *  @brief Assign the result of a function object to each value in a
	   *         sequence.
	   *  @ingroup mutating_algorithms
	   *  @param  __first  A forward iterator.
	   *  @param  __n      The length of the sequence.
	   *  @param  __gen    A function object taking no arguments and returning
	   *                 std::iterator_traits<_ForwardIterator>::value_type
	   *  @return   The end of the sequence, @p __first+__n
	   *
	   *  Performs the assignment @c *i = @p __gen() for each @c i in the range
	   *  @p [__first,__first+__n).
	   *
	   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
	   *  DR 865. More algorithms that throw away information
	  */
	  template<typename _OutputIterator, typename _Size, typename _Generator>
	    _OutputIterator
	    generate_n(_OutputIterator __first, _Size __n, _Generator __gen)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
	            // "the type returned by a _Generator"
	            __typeof__(__gen())>)
	
	      for (__decltype(__n + 0) __niter = __n;
		   __niter > 0; --__niter, ++__first)
		*__first = __gen();
	      return __first;
	    }
	
	
	  /**
	   *  @brief Copy a sequence, removing consecutive duplicate values.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   An input iterator.
	   *  @param  __last    An input iterator.
	   *  @param  __result  An output iterator.
	   *  @return   An iterator designating the end of the resulting sequence.
	   *
	   *  Copies each element in the range @p [__first,__last) to the range
	   *  beginning at @p __result, except that only the first element is copied
	   *  from groups of consecutive elements that compare equal.
	   *  unique_copy() is stable, so the relative order of elements that are
	   *  copied is unchanged.
	   *
	   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
	   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
	   *  
	   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
	   *  DR 538. 241 again: Does unique_copy() require CopyConstructible and 
	   *  Assignable?
	  */
	  template<typename _InputIterator, typename _OutputIterator>
	    inline _OutputIterator
	    unique_copy(_InputIterator __first, _InputIterator __last,
			_OutputIterator __result)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_function_requires(_EqualityComparableConcept<
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first == __last)
		return __result;
	      return std::__unique_copy(__first, __last, __result,
					std::__iterator_category(__first),
					std::__iterator_category(__result));
	    }
	
	  /**
	   *  @brief Copy a sequence, removing consecutive values using a predicate.
	   *  @ingroup mutating_algorithms
	   *  @param  __first        An input iterator.
	   *  @param  __last         An input iterator.
	   *  @param  __result       An output iterator.
	   *  @param  __binary_pred  A binary predicate.
	   *  @return   An iterator designating the end of the resulting sequence.
	   *
	   *  Copies each element in the range @p [__first,__last) to the range
	   *  beginning at @p __result, except that only the first element is copied
	   *  from groups of consecutive elements for which @p __binary_pred returns
	   *  true.
	   *  unique_copy() is stable, so the relative order of elements that are
	   *  copied is unchanged.
	   *
	   *  _GLIBCXX_RESOLVE_LIB_DEFECTS
	   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?
	  */
	  template<typename _InputIterator, typename _OutputIterator,
		   typename _BinaryPredicate>
	    inline _OutputIterator
	    unique_copy(_InputIterator __first, _InputIterator __last,
			_OutputIterator __result,
			_BinaryPredicate __binary_pred)
	    {
	      // concept requirements -- predicates checked later
	      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
	      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
		    typename iterator_traits<_InputIterator>::value_type>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first == __last)
		return __result;
	      return std::__unique_copy(__first, __last, __result, __binary_pred,
					std::__iterator_category(__first),
					std::__iterator_category(__result));
	    }
	
	
	  /**
	   *  @brief Randomly shuffle the elements of a sequence.
	   *  @ingroup mutating_algorithms
	   *  @param  __first   A forward iterator.
	   *  @param  __last    A forward iterator.
	   *  @return  Nothing.
	   *
	   *  Reorder the elements in the range @p [__first,__last) using a random
	   *  distribution, so that every possible ordering of the sequence is
	   *  equally likely.
	  */
	  template<typename _RandomAccessIterator>
	    inline void
	    random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
	    {
	      // concept requirements
	      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
		    _RandomAccessIterator>)
	      __glibcxx_requires_valid_range(__first, __last);
	
	      if (__first != __last)
		for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)