1 // Heap implementation -*- C++ -*-
2
3 // Copyright (C) 2001-2013 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24
25 /*
26 *
27 * Copyright (c) 1994
28 * Hewlett-Packard Company
29 *
30 * Permission to use, copy, modify, distribute and sell this software
31 * and its documentation for any purpose is hereby granted without fee,
32 * provided that the above copyright notice appear in all copies and
33 * that both that copyright notice and this permission notice appear
34 * in supporting documentation. Hewlett-Packard Company makes no
35 * representations about the suitability of this software for any
36 * purpose. It is provided "as is" without express or implied warranty.
37 *
38 * Copyright (c) 1997
39 * Silicon Graphics Computer Systems, Inc.
40 *
41 * Permission to use, copy, modify, distribute and sell this software
42 * and its documentation for any purpose is hereby granted without fee,
43 * provided that the above copyright notice appear in all copies and
44 * that both that copyright notice and this permission notice appear
45 * in supporting documentation. Silicon Graphics makes no
46 * representations about the suitability of this software for any
47 * purpose. It is provided "as is" without express or implied warranty.
48 */
49
50 /** @file bits/stl_heap.h
51 * This is an internal header file, included by other library headers.
52 * Do not attempt to use it directly. @headername{queue}
53 */
54
55 #ifndef _STL_HEAP_H
56 #define _STL_HEAP_H 1
57
58 #include <debug/debug.h>
59 #include <bits/move.h>
60
61 namespace std _GLIBCXX_VISIBILITY(default)
62 {
63 _GLIBCXX_BEGIN_NAMESPACE_VERSION
64
65 /**
66 * @defgroup heap_algorithms Heap
67 * @ingroup sorting_algorithms
68 */
69
70 template<typename _RandomAccessIterator, typename _Distance>
71 _Distance
72 __is_heap_until(_RandomAccessIterator __first, _Distance __n)
73 {
74 _Distance __parent = 0;
75 for (_Distance __child = 1; __child < __n; ++__child)
76 {
77 if (__first[__parent] < __first[__child])
78 return __child;
79 if ((__child & 1) == 0)
80 ++__parent;
81 }
82 return __n;
83 }
84
85 template<typename _RandomAccessIterator, typename _Distance,
86 typename _Compare>
87 _Distance
88 __is_heap_until(_RandomAccessIterator __first, _Distance __n,
89 _Compare __comp)
90 {
91 _Distance __parent = 0;
92 for (_Distance __child = 1; __child < __n; ++__child)
93 {
94 if (__comp(__first[__parent], __first[__child]))
95 return __child;
96 if ((__child & 1) == 0)
97 ++__parent;
98 }
99 return __n;
100 }
101
102 // __is_heap, a predicate testing whether or not a range is a heap.
103 // This function is an extension, not part of the C++ standard.
104 template<typename _RandomAccessIterator, typename _Distance>
105 inline bool
106 __is_heap(_RandomAccessIterator __first, _Distance __n)
107 { return std::__is_heap_until(__first, __n) == __n; }
108
109 template<typename _RandomAccessIterator, typename _Compare,
110 typename _Distance>
111 inline bool
112 __is_heap(_RandomAccessIterator __first, _Compare __comp, _Distance __n)
113 { return std::__is_heap_until(__first, __n, __comp) == __n; }
114
115 template<typename _RandomAccessIterator>
116 inline bool
117 __is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
118 { return std::__is_heap(__first, std::distance(__first, __last)); }
119
120 template<typename _RandomAccessIterator, typename _Compare>
121 inline bool
122 __is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
123 _Compare __comp)
124 { return std::__is_heap(__first, __comp, std::distance(__first, __last)); }
125
126 // Heap-manipulation functions: push_heap, pop_heap, make_heap, sort_heap,
127 // + is_heap and is_heap_until in C++0x.
128
129 template<typename _RandomAccessIterator, typename _Distance, typename _Tp>
130 void
131 __push_heap(_RandomAccessIterator __first,
132 _Distance __holeIndex, _Distance __topIndex, _Tp __value)
133 {
134 _Distance __parent = (__holeIndex - 1) / 2;
135 while (__holeIndex > __topIndex && *(__first + __parent) < __value)
136 {
137 *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first + __parent));
138 __holeIndex = __parent;
139 __parent = (__holeIndex - 1) / 2;
140 }
141 *(__first + __holeIndex) = _GLIBCXX_MOVE(__value);
142 }
143
144 /**
145 * @brief Push an element onto a heap.
146 * @param __first Start of heap.
147 * @param __last End of heap + element.
148 * @ingroup heap_algorithms
149 *
150 * This operation pushes the element at last-1 onto the valid heap
151 * over the range [__first,__last-1). After completion,
152 * [__first,__last) is a valid heap.
153 */
154 template<typename _RandomAccessIterator>
155 inline void
156 push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
157 {
158 typedef typename iterator_traits<_RandomAccessIterator>::value_type
159 _ValueType;
160 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
161 _DistanceType;
162
163 // concept requirements
164 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
165 _RandomAccessIterator>)
166 __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
167 __glibcxx_requires_valid_range(__first, __last);
168 __glibcxx_requires_heap(__first, __last - 1);
169
170 _ValueType __value = _GLIBCXX_MOVE(*(__last - 1));
171 std::__push_heap(__first, _DistanceType((__last - __first) - 1),
172 _DistanceType(0), _GLIBCXX_MOVE(__value));
173 }
174
175 template<typename _RandomAccessIterator, typename _Distance, typename _Tp,
176 typename _Compare>
177 void
178 __push_heap(_RandomAccessIterator __first, _Distance __holeIndex,
179 _Distance __topIndex, _Tp __value, _Compare __comp)
180 {
181 _Distance __parent = (__holeIndex - 1) / 2;
182 while (__holeIndex > __topIndex
183 && __comp(*(__first + __parent), __value))
184 {
185 *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first + __parent));
186 __holeIndex = __parent;
187 __parent = (__holeIndex - 1) / 2;
188 }
189 *(__first + __holeIndex) = _GLIBCXX_MOVE(__value);
190 }
191
192 /**
193 * @brief Push an element onto a heap using comparison functor.
194 * @param __first Start of heap.
195 * @param __last End of heap + element.
196 * @param __comp Comparison functor.
197 * @ingroup heap_algorithms
198 *
199 * This operation pushes the element at __last-1 onto the valid
200 * heap over the range [__first,__last-1). After completion,
201 * [__first,__last) is a valid heap. Compare operations are
202 * performed using comp.
203 */
204 template<typename _RandomAccessIterator, typename _Compare>
205 inline void
206 push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
207 _Compare __comp)
208 {
209 typedef typename iterator_traits<_RandomAccessIterator>::value_type
210 _ValueType;
211 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
212 _DistanceType;
213
214 // concept requirements
215 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
216 _RandomAccessIterator>)
217 __glibcxx_requires_valid_range(__first, __last);
218 __glibcxx_requires_heap_pred(__first, __last - 1, __comp);
219
220 _ValueType __value = _GLIBCXX_MOVE(*(__last - 1));
221 std::__push_heap(__first, _DistanceType((__last - __first) - 1),
222 _DistanceType(0), _GLIBCXX_MOVE(__value), __comp);
223 }
224
225 template<typename _RandomAccessIterator, typename _Distance, typename _Tp>
226 void
227 __adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex,
228 _Distance __len, _Tp __value)
229 {
230 const _Distance __topIndex = __holeIndex;
231 _Distance __secondChild = __holeIndex;
232 while (__secondChild < (__len - 1) / 2)
233 {
234 __secondChild = 2 * (__secondChild + 1);
235 if (*(__first + __secondChild) < *(__first + (__secondChild - 1)))
236 __secondChild--;
237 *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first + __secondChild));
238 __holeIndex = __secondChild;
239 }
240 if ((__len & 1) == 0 && __secondChild == (__len - 2) / 2)
241 {
242 __secondChild = 2 * (__secondChild + 1);
243 *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first
244 + (__secondChild - 1)));
245 __holeIndex = __secondChild - 1;
246 }
247 std::__push_heap(__first, __holeIndex, __topIndex,
248 _GLIBCXX_MOVE(__value));
249 }
250
251 template<typename _RandomAccessIterator>
252 inline void
253 __pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
254 _RandomAccessIterator __result)
255 {
256 typedef typename iterator_traits<_RandomAccessIterator>::value_type
257 _ValueType;
258 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
259 _DistanceType;
260
261 _ValueType __value = _GLIBCXX_MOVE(*__result);
262 *__result = _GLIBCXX_MOVE(*__first);
263 std::__adjust_heap(__first, _DistanceType(0),
264 _DistanceType(__last - __first),
265 _GLIBCXX_MOVE(__value));
266 }
267
268 /**
269 * @brief Pop an element off a heap.
270 * @param __first Start of heap.
271 * @param __last End of heap.
272 * @pre [__first, __last) is a valid, non-empty range.
273 * @ingroup heap_algorithms
274 *
275 * This operation pops the top of the heap. The elements __first
276 * and __last-1 are swapped and [__first,__last-1) is made into a
277 * heap.
278 */
279 template<typename _RandomAccessIterator>
280 inline void
281 pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
282 {
283 typedef typename iterator_traits<_RandomAccessIterator>::value_type
284 _ValueType;
285
286 // concept requirements
287 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
288 _RandomAccessIterator>)
289 __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
290 __glibcxx_requires_non_empty_range(__first, __last);
291 __glibcxx_requires_valid_range(__first, __last);
292 __glibcxx_requires_heap(__first, __last);
293
294 if (__last - __first > 1)
295 {
296 --__last;
297 std::__pop_heap(__first, __last, __last);
298 }
299 }
300
301 template<typename _RandomAccessIterator, typename _Distance,
302 typename _Tp, typename _Compare>
303 void
304 __adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex,
305 _Distance __len, _Tp __value, _Compare __comp)
306 {
307 const _Distance __topIndex = __holeIndex;
308 _Distance __secondChild = __holeIndex;
309 while (__secondChild < (__len - 1) / 2)
310 {
311 __secondChild = 2 * (__secondChild + 1);
312 if (__comp(*(__first + __secondChild),
313 *(__first + (__secondChild - 1))))
314 __secondChild--;
315 *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first + __secondChild));
316 __holeIndex = __secondChild;
317 }
318 if ((__len & 1) == 0 && __secondChild == (__len - 2) / 2)
319 {
320 __secondChild = 2 * (__secondChild + 1);
321 *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first
322 + (__secondChild - 1)));
323 __holeIndex = __secondChild - 1;
324 }
325 std::__push_heap(__first, __holeIndex, __topIndex,
326 _GLIBCXX_MOVE(__value), __comp);
327 }
328
329 template<typename _RandomAccessIterator, typename _Compare>
330 inline void
331 __pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
332 _RandomAccessIterator __result, _Compare __comp)
333 {
334 typedef typename iterator_traits<_RandomAccessIterator>::value_type
335 _ValueType;
336 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
337 _DistanceType;
338
339 _ValueType __value = _GLIBCXX_MOVE(*__result);
340 *__result = _GLIBCXX_MOVE(*__first);
341 std::__adjust_heap(__first, _DistanceType(0),
342 _DistanceType(__last - __first),
343 _GLIBCXX_MOVE(__value), __comp);
344 }
345
346 /**
347 * @brief Pop an element off a heap using comparison functor.
348 * @param __first Start of heap.
349 * @param __last End of heap.
350 * @param __comp Comparison functor to use.
351 * @ingroup heap_algorithms
352 *
353 * This operation pops the top of the heap. The elements __first
354 * and __last-1 are swapped and [__first,__last-1) is made into a
355 * heap. Comparisons are made using comp.
356 */
357 template<typename _RandomAccessIterator, typename _Compare>
358 inline void
359 pop_heap(_RandomAccessIterator __first,
360 _RandomAccessIterator __last, _Compare __comp)
361 {
362 // concept requirements
363 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
364 _RandomAccessIterator>)
365 __glibcxx_requires_valid_range(__first, __last);
366 __glibcxx_requires_non_empty_range(__first, __last);
367 __glibcxx_requires_heap_pred(__first, __last, __comp);
368
369 if (__last - __first > 1)
370 {
371 --__last;
372 std::__pop_heap(__first, __last, __last, __comp);
373 }
374 }
375
376 /**
377 * @brief Construct a heap over a range.
378 * @param __first Start of heap.
379 * @param __last End of heap.
380 * @ingroup heap_algorithms
381 *
382 * This operation makes the elements in [__first,__last) into a heap.
383 */
384 template<typename _RandomAccessIterator>
385 void
386 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
387 {
388 typedef typename iterator_traits<_RandomAccessIterator>::value_type
389 _ValueType;
390 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
391 _DistanceType;
392
393 // concept requirements
394 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
395 _RandomAccessIterator>)
396 __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
397 __glibcxx_requires_valid_range(__first, __last);
398
399 if (__last - __first < 2)
400 return;
401
402 const _DistanceType __len = __last - __first;
403 _DistanceType __parent = (__len - 2) / 2;
404 while (true)
405 {
406 _ValueType __value = _GLIBCXX_MOVE(*(__first + __parent));
407 std::__adjust_heap(__first, __parent, __len, _GLIBCXX_MOVE(__value));
408 if (__parent == 0)
409 return;
410 __parent--;
411 }
412 }
413
414 /**
415 * @brief Construct a heap over a range using comparison functor.
416 * @param __first Start of heap.
417 * @param __last End of heap.
418 * @param __comp Comparison functor to use.
419 * @ingroup heap_algorithms
420 *
421 * This operation makes the elements in [__first,__last) into a heap.
422 * Comparisons are made using __comp.
423 */
424 template<typename _RandomAccessIterator, typename _Compare>
425 void
426 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
427 _Compare __comp)
428 {
429 typedef typename iterator_traits<_RandomAccessIterator>::value_type
430 _ValueType;
431 typedef typename iterator_traits<_RandomAccessIterator>::difference_type
432 _DistanceType;
433
434 // concept requirements
435 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
436 _RandomAccessIterator>)
437 __glibcxx_requires_valid_range(__first, __last);
438
439 if (__last - __first < 2)
440 return;
441
442 const _DistanceType __len = __last - __first;
443 _DistanceType __parent = (__len - 2) / 2;
444 while (true)
445 {
446 _ValueType __value = _GLIBCXX_MOVE(*(__first + __parent));
447 std::__adjust_heap(__first, __parent, __len, _GLIBCXX_MOVE(__value),
448 __comp);
449 if (__parent == 0)
450 return;
451 __parent--;
452 }
453 }
454
455 /**
456 * @brief Sort a heap.
457 * @param __first Start of heap.
458 * @param __last End of heap.
459 * @ingroup heap_algorithms
460 *
461 * This operation sorts the valid heap in the range [__first,__last).
462 */
463 template<typename _RandomAccessIterator>
464 void
465 sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
466 {
467 // concept requirements
468 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
469 _RandomAccessIterator>)
470 __glibcxx_function_requires(_LessThanComparableConcept<
471 typename iterator_traits<_RandomAccessIterator>::value_type>)
472 __glibcxx_requires_valid_range(__first, __last);
473 __glibcxx_requires_heap(__first, __last);
474
475 while (__last - __first > 1)
476 {
477 --__last;
478 std::__pop_heap(__first, __last, __last);
479 }
480 }
481
482 /**
483 * @brief Sort a heap using comparison functor.
484 * @param __first Start of heap.
485 * @param __last End of heap.
486 * @param __comp Comparison functor to use.
487 * @ingroup heap_algorithms
488 *
489 * This operation sorts the valid heap in the range [__first,__last).
490 * Comparisons are made using __comp.
491 */
492 template<typename _RandomAccessIterator, typename _Compare>
493 void
494 sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
495 _Compare __comp)
496 {
497 // concept requirements
498 __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
499 _RandomAccessIterator>)
500 __glibcxx_requires_valid_range(__first, __last);
501 __glibcxx_requires_heap_pred(__first, __last, __comp);
502
503 while (__last - __first > 1)
504 {
505 --__last;
506 std::__pop_heap(__first, __last, __last, __comp);
507 }
508 }
509
510 #if __cplusplus >= 201103L
511 /**
512 * @brief Search the end of a heap.
513 * @param __first Start of range.
514 * @param __last End of range.
515 * @return An iterator pointing to the first element not in the heap.
516 * @ingroup heap_algorithms
517 *
518 * This operation returns the last iterator i in [__first, __last) for which
519 * the range [__first, i) is a heap.
520 */
521 template<typename _RandomAccessIterator>
522 inline _RandomAccessIterator
523 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
524 {
525 // concept requirements
526 __glibcxx_function_requires(_RandomAccessIteratorConcept<
527 _RandomAccessIterator>)
528 __glibcxx_function_requires(_LessThanComparableConcept<
529 typename iterator_traits<_RandomAccessIterator>::value_type>)
530 __glibcxx_requires_valid_range(__first, __last);
531
532 return __first + std::__is_heap_until(__first, std::distance(__first,
533 __last));
534 }
535
536 /**
537 * @brief Search the end of a heap using comparison functor.
538 * @param __first Start of range.
539 * @param __last End of range.
540 * @param __comp Comparison functor to use.
541 * @return An iterator pointing to the first element not in the heap.
542 * @ingroup heap_algorithms
543 *
544 * This operation returns the last iterator i in [__first, __last) for which
545 * the range [__first, i) is a heap. Comparisons are made using __comp.
546 */
547 template<typename _RandomAccessIterator, typename _Compare>
548 inline _RandomAccessIterator
549 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last,
550 _Compare __comp)
551 {
552 // concept requirements
553 __glibcxx_function_requires(_RandomAccessIteratorConcept<
554 _RandomAccessIterator>)
555 __glibcxx_requires_valid_range(__first, __last);
556
557 return __first + std::__is_heap_until(__first, std::distance(__first,
558 __last),
559 __comp);
560 }
561
562 /**
563 * @brief Determines whether a range is a heap.
564 * @param __first Start of range.
565 * @param __last End of range.
566 * @return True if range is a heap, false otherwise.
567 * @ingroup heap_algorithms
568 */
569 template<typename _RandomAccessIterator>
570 inline bool
571 is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
572 { return std::is_heap_until(__first, __last) == __last; }
573
574 /**
575 * @brief Determines whether a range is a heap using comparison functor.
576 * @param __first Start of range.
577 * @param __last End of range.
578 * @param __comp Comparison functor to use.
579 * @return True if range is a heap, false otherwise.
580 * @ingroup heap_algorithms
581 */
582 template<typename _RandomAccessIterator, typename _Compare>
583 inline bool
584 is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
585 _Compare __comp)
586 { return std::is_heap_until(__first, __last, __comp) == __last; }
587 #endif
588
589 _GLIBCXX_END_NAMESPACE_VERSION
590 } // namespace
591
592 #endif /* _STL_HEAP_H */
593