1// Queue implementation -*- C++ -*-
2
3// Copyright (C) 2001-2021 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 *
39 * Copyright (c) 1996,1997
40 * Silicon Graphics Computer Systems, Inc.
41 *
42 * Permission to use, copy, modify, distribute and sell this software
43 * and its documentation for any purpose is hereby granted without fee,
44 * provided that the above copyright notice appear in all copies and
45 * that both that copyright notice and this permission notice appear
46 * in supporting documentation. Silicon Graphics makes no
47 * representations about the suitability of this software for any
48 * purpose. It is provided "as is" without express or implied warranty.
49 */
50
51/** @file bits/stl_queue.h
52 * This is an internal header file, included by other library headers.
53 * Do not attempt to use it directly. @headername{queue}
54 */
55
56#ifndef _STL_QUEUE_H
57#define _STL_QUEUE_H 1
58
59#include <bits/concept_check.h>
60#include <debug/debug.h>
61#if __cplusplus >= 201103L
62# include <bits/uses_allocator.h>
63#endif
64
65namespace std _GLIBCXX_VISIBILITY(default)
66{
67_GLIBCXX_BEGIN_NAMESPACE_VERSION
68
69 /**
70 * @brief A standard container giving FIFO behavior.
71 *
72 * @ingroup sequences
73 *
74 * @tparam _Tp Type of element.
75 * @tparam _Sequence Type of underlying sequence, defaults to deque<_Tp>.
76 *
77 * Meets many of the requirements of a
78 * <a href="tables.html#65">container</a>,
79 * but does not define anything to do with iterators. Very few of the
80 * other standard container interfaces are defined.
81 *
82 * This is not a true container, but an @e adaptor. It holds another
83 * container, and provides a wrapper interface to that container. The
84 * wrapper is what enforces strict first-in-first-out %queue behavior.
85 *
86 * The second template parameter defines the type of the underlying
87 * sequence/container. It defaults to std::deque, but it can be any type
88 * that supports @c front, @c back, @c push_back, and @c pop_front,
89 * such as std::list or an appropriate user-defined type.
90 *
91 * Members not found in @a normal containers are @c container_type,
92 * which is a typedef for the second Sequence parameter, and @c push and
93 * @c pop, which are standard %queue/FIFO operations.
94 */
95 template<typename _Tp, typename _Sequence = deque<_Tp> >
96 class queue
97 {
98#ifdef _GLIBCXX_CONCEPT_CHECKS
99 // concept requirements
100 typedef typename _Sequence::value_type _Sequence_value_type;
101# if __cplusplus < 201103L
102 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
103# endif
104 __glibcxx_class_requires(_Sequence, _FrontInsertionSequenceConcept)
105 __glibcxx_class_requires(_Sequence, _BackInsertionSequenceConcept)
106 __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
107#endif
108
109 template<typename _Tp1, typename _Seq1>
110 friend bool
111 operator==(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
112
113 template<typename _Tp1, typename _Seq1>
114 friend bool
115 operator<(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
116
117#if __cpp_lib_three_way_comparison
118 template<typename _Tp1, three_way_comparable _Seq1>
119 friend compare_three_way_result_t<_Seq1>
120 operator<=>(const queue<_Tp1, _Seq1>&, const queue<_Tp1, _Seq1>&);
121#endif
122
123#if __cplusplus >= 201103L
124 template<typename _Alloc>
125 using _Uses = typename
126 enable_if<uses_allocator<_Sequence, _Alloc>::value>::type;
127
128#if __cplusplus >= 201703L
129 // _GLIBCXX_RESOLVE_LIB_DEFECTS
130 // 2566. Requirements on the first template parameter of container
131 // adaptors
132 static_assert(is_same<_Tp, typename _Sequence::value_type>::value,
133 "value_type must be the same as the underlying container");
134#endif // C++17
135#endif // C++11
136
137 public:
138 typedef typename _Sequence::value_type value_type;
139 typedef typename _Sequence::reference reference;
140 typedef typename _Sequence::const_reference const_reference;
141 typedef typename _Sequence::size_type size_type;
142 typedef _Sequence container_type;
143
144 protected:
145 /* Maintainers wondering why this isn't uglified as per style
146 * guidelines should note that this name is specified in the standard,
147 * C++98 [23.2.3.1].
148 * (Why? Presumably for the same reason that it's protected instead
149 * of private: to allow derivation. But none of the other
150 * containers allow for derivation. Odd.)
151 */
152 /// @c c is the underlying container.
153 _Sequence c;
154
155 public:
156 /**
157 * @brief Default constructor creates no elements.
158 */
159#if __cplusplus < 201103L
160 explicit
161 queue(const _Sequence& __c = _Sequence())
162 : c(__c) { }
163#else
164 template<typename _Seq = _Sequence, typename _Requires = typename
165 enable_if<is_default_constructible<_Seq>::value>::type>
166 queue()
167 : c() { }
168
169 explicit
170 queue(const _Sequence& __c)
171 : c(__c) { }
172
173 explicit
174 queue(_Sequence&& __c)
175 : c(std::move(__c)) { }
176
177 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
178 explicit
179 queue(const _Alloc& __a)
180 : c(__a) { }
181
182 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
183 queue(const _Sequence& __c, const _Alloc& __a)
184 : c(__c, __a) { }
185
186 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
187 queue(_Sequence&& __c, const _Alloc& __a)
188 : c(std::move(__c), __a) { }
189
190 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
191 queue(const queue& __q, const _Alloc& __a)
192 : c(__q.c, __a) { }
193
194 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
195 queue(queue&& __q, const _Alloc& __a)
196 : c(std::move(__q.c), __a) { }
197#endif
198
199 /**
200 * Returns true if the %queue is empty.
201 */
202 _GLIBCXX_NODISCARD bool
203 empty() const
204 { return c.empty(); }
205
206 /** Returns the number of elements in the %queue. */
207 size_type
208 size() const
209 { return c.size(); }
210
211 /**
212 * Returns a read/write reference to the data at the first
213 * element of the %queue.
214 */
215 reference
216 front()
217 {
218 __glibcxx_requires_nonempty();
219 return c.front();
220 }
221
222 /**
223 * Returns a read-only (constant) reference to the data at the first
224 * element of the %queue.
225 */
226 const_reference
227 front() const
228 {
229 __glibcxx_requires_nonempty();
230 return c.front();
231 }
232
233 /**
234 * Returns a read/write reference to the data at the last
235 * element of the %queue.
236 */
237 reference
238 back()
239 {
240 __glibcxx_requires_nonempty();
241 return c.back();
242 }
243
244 /**
245 * Returns a read-only (constant) reference to the data at the last
246 * element of the %queue.
247 */
248 const_reference
249 back() const
250 {
251 __glibcxx_requires_nonempty();
252 return c.back();
253 }
254
255 /**
256 * @brief Add data to the end of the %queue.
257 * @param __x Data to be added.
258 *
259 * This is a typical %queue operation. The function creates an
260 * element at the end of the %queue and assigns the given data
261 * to it. The time complexity of the operation depends on the
262 * underlying sequence.
263 */
264 void
265 push(const value_type& __x)
266 { c.push_back(__x); }
267
268#if __cplusplus >= 201103L
269 void
270 push(value_type&& __x)
271 { c.push_back(std::move(__x)); }
272
273#if __cplusplus > 201402L
274 template<typename... _Args>
275 decltype(auto)
276 emplace(_Args&&... __args)
277 { return c.emplace_back(std::forward<_Args>(__args)...); }
278#else
279 template<typename... _Args>
280 void
281 emplace(_Args&&... __args)
282 { c.emplace_back(std::forward<_Args>(__args)...); }
283#endif
284#endif
285
286 /**
287 * @brief Removes first element.
288 *
289 * This is a typical %queue operation. It shrinks the %queue by one.
290 * The time complexity of the operation depends on the underlying
291 * sequence.
292 *
293 * Note that no data is returned, and if the first element's
294 * data is needed, it should be retrieved before pop() is
295 * called.
296 */
297 void
298 pop()
299 {
300 __glibcxx_requires_nonempty();
301 c.pop_front();
302 }
303
304#if __cplusplus >= 201103L
305 void
306 swap(queue& __q)
307#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
308 noexcept(__is_nothrow_swappable<_Sequence>::value)
309#else
310 noexcept(__is_nothrow_swappable<_Tp>::value)
311#endif
312 {
313 using std::swap;
314 swap(c, __q.c);
315 }
316#endif // __cplusplus >= 201103L
317 };
318
319#if __cpp_deduction_guides >= 201606
320 template<typename _Container,
321 typename = _RequireNotAllocator<_Container>>
322 queue(_Container) -> queue<typename _Container::value_type, _Container>;
323
324 template<typename _Container, typename _Allocator,
325 typename = _RequireNotAllocator<_Container>,
326 typename = _RequireAllocator<_Allocator>>
327 queue(_Container, _Allocator)
328 -> queue<typename _Container::value_type, _Container>;
329#endif
330
331 /**
332 * @brief Queue equality comparison.
333 * @param __x A %queue.
334 * @param __y A %queue of the same type as @a __x.
335 * @return True iff the size and elements of the queues are equal.
336 *
337 * This is an equivalence relation. Complexity and semantics depend on the
338 * underlying sequence type, but the expected rules are: this relation is
339 * linear in the size of the sequences, and queues are considered equivalent
340 * if their sequences compare equal.
341 */
342 template<typename _Tp, typename _Seq>
343 inline bool
344 operator==(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
345 { return __x.c == __y.c; }
346
347 /**
348 * @brief Queue ordering relation.
349 * @param __x A %queue.
350 * @param __y A %queue of the same type as @a x.
351 * @return True iff @a __x is lexicographically less than @a __y.
352 *
353 * This is an total ordering relation. Complexity and semantics
354 * depend on the underlying sequence type, but the expected rules
355 * are: this relation is linear in the size of the sequences, the
356 * elements must be comparable with @c <, and
357 * std::lexicographical_compare() is usually used to make the
358 * determination.
359 */
360 template<typename _Tp, typename _Seq>
361 inline bool
362 operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
363 { return __x.c < __y.c; }
364
365 /// Based on operator==
366 template<typename _Tp, typename _Seq>
367 inline bool
368 operator!=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
369 { return !(__x == __y); }
370
371 /// Based on operator<
372 template<typename _Tp, typename _Seq>
373 inline bool
374 operator>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
375 { return __y < __x; }
376
377 /// Based on operator<
378 template<typename _Tp, typename _Seq>
379 inline bool
380 operator<=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
381 { return !(__y < __x); }
382
383 /// Based on operator<
384 template<typename _Tp, typename _Seq>
385 inline bool
386 operator>=(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
387 { return !(__x < __y); }
388
389#if __cpp_lib_three_way_comparison
390 template<typename _Tp, three_way_comparable _Seq>
391 inline compare_three_way_result_t<_Seq>
392 operator<=>(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
393 { return __x.c <=> __y.c; }
394#endif
395
396#if __cplusplus >= 201103L
397 template<typename _Tp, typename _Seq>
398 inline
399#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
400 // Constrained free swap overload, see p0185r1
401 typename enable_if<__is_swappable<_Seq>::value>::type
402#else
403 void
404#endif
405 swap(queue<_Tp, _Seq>& __x, queue<_Tp, _Seq>& __y)
406 noexcept(noexcept(__x.swap(__y)))
407 { __x.swap(__y); }
408
409 template<typename _Tp, typename _Seq, typename _Alloc>
410 struct uses_allocator<queue<_Tp, _Seq>, _Alloc>
411 : public uses_allocator<_Seq, _Alloc>::type { };
412#endif // __cplusplus >= 201103L
413
414 /**
415 * @brief A standard container automatically sorting its contents.
416 *
417 * @ingroup sequences
418 *
419 * @tparam _Tp Type of element.
420 * @tparam _Sequence Type of underlying sequence, defaults to vector<_Tp>.
421 * @tparam _Compare Comparison function object type, defaults to
422 * less<_Sequence::value_type>.
423 *
424 * This is not a true container, but an @e adaptor. It holds
425 * another container, and provides a wrapper interface to that
426 * container. The wrapper is what enforces priority-based sorting
427 * and %queue behavior. Very few of the standard container/sequence
428 * interface requirements are met (e.g., iterators).
429 *
430 * The second template parameter defines the type of the underlying
431 * sequence/container. It defaults to std::vector, but it can be
432 * any type that supports @c front(), @c push_back, @c pop_back,
433 * and random-access iterators, such as std::deque or an
434 * appropriate user-defined type.
435 *
436 * The third template parameter supplies the means of making
437 * priority comparisons. It defaults to @c less<value_type> but
438 * can be anything defining a strict weak ordering.
439 *
440 * Members not found in @a normal containers are @c container_type,
441 * which is a typedef for the second Sequence parameter, and @c
442 * push, @c pop, and @c top, which are standard %queue operations.
443 *
444 * @note No equality/comparison operators are provided for
445 * %priority_queue.
446 *
447 * @note Sorting of the elements takes place as they are added to,
448 * and removed from, the %priority_queue using the
449 * %priority_queue's member functions. If you access the elements
450 * by other means, and change their data such that the sorting
451 * order would be different, the %priority_queue will not re-sort
452 * the elements for you. (How could it know to do so?)
453 */
454 template<typename _Tp, typename _Sequence = vector<_Tp>,
455 typename _Compare = less<typename _Sequence::value_type> >
456 class priority_queue
457 {
458#ifdef _GLIBCXX_CONCEPT_CHECKS
459 // concept requirements
460 typedef typename _Sequence::value_type _Sequence_value_type;
461# if __cplusplus < 201103L
462 __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
463# endif
464 __glibcxx_class_requires(_Sequence, _SequenceConcept)
465 __glibcxx_class_requires(_Sequence, _RandomAccessContainerConcept)
466 __glibcxx_class_requires2(_Tp, _Sequence_value_type, _SameTypeConcept)
467 __glibcxx_class_requires4(_Compare, bool, _Tp, _Tp,
468 _BinaryFunctionConcept)
469#endif
470
471#if __cplusplus >= 201103L
472 template<typename _Alloc>
473 using _Uses = typename
474 enable_if<uses_allocator<_Sequence, _Alloc>::value>::type;
475
476#if __cplusplus >= 201703L
477 // _GLIBCXX_RESOLVE_LIB_DEFECTS
478 // 2566. Requirements on the first template parameter of container
479 // adaptors
480 static_assert(is_same<_Tp, typename _Sequence::value_type>::value,
481 "value_type must be the same as the underlying container");
482#endif // C++17
483#endif // C++11
484
485 public:
486 typedef typename _Sequence::value_type value_type;
487 typedef typename _Sequence::reference reference;
488 typedef typename _Sequence::const_reference const_reference;
489 typedef typename _Sequence::size_type size_type;
490 typedef _Sequence container_type;
491 // _GLIBCXX_RESOLVE_LIB_DEFECTS
492 // DR 2684. priority_queue lacking comparator typedef
493 typedef _Compare value_compare;
494
495 protected:
496 // See queue::c for notes on these names.
497 _Sequence c;
498 _Compare comp;
499
500 public:
501 /**
502 * @brief Default constructor creates no elements.
503 */
504#if __cplusplus < 201103L
505 explicit
506 priority_queue(const _Compare& __x = _Compare(),
507 const _Sequence& __s = _Sequence())
508 : c(__s), comp(__x)
509 { std::make_heap(c.begin(), c.end(), comp); }
510#else
511 template<typename _Seq = _Sequence, typename _Requires = typename
512 enable_if<__and_<is_default_constructible<_Compare>,
513 is_default_constructible<_Seq>>::value>::type>
514 priority_queue()
515 : c(), comp() { }
516
517 explicit
518 priority_queue(const _Compare& __x, const _Sequence& __s)
519 : c(__s), comp(__x)
520 { std::make_heap(c.begin(), c.end(), comp); }
521
522 explicit
523 priority_queue(const _Compare& __x, _Sequence&& __s = _Sequence())
524 : c(std::move(__s)), comp(__x)
525 { std::make_heap(c.begin(), c.end(), comp); }
526
527 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
528 explicit
529 priority_queue(const _Alloc& __a)
530 : c(__a), comp() { }
531
532 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
533 priority_queue(const _Compare& __x, const _Alloc& __a)
534 : c(__a), comp(__x) { }
535
536 // _GLIBCXX_RESOLVE_LIB_DEFECTS
537 // 2537. Constructors [...] taking allocators should call make_heap
538 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
539 priority_queue(const _Compare& __x, const _Sequence& __c,
540 const _Alloc& __a)
541 : c(__c, __a), comp(__x)
542 { std::make_heap(c.begin(), c.end(), comp); }
543
544 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
545 priority_queue(const _Compare& __x, _Sequence&& __c, const _Alloc& __a)
546 : c(std::move(__c), __a), comp(__x)
547 { std::make_heap(c.begin(), c.end(), comp); }
548
549 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
550 priority_queue(const priority_queue& __q, const _Alloc& __a)
551 : c(__q.c, __a), comp(__q.comp) { }
552
553 template<typename _Alloc, typename _Requires = _Uses<_Alloc>>
554 priority_queue(priority_queue&& __q, const _Alloc& __a)
555 : c(std::move(__q.c), __a), comp(std::move(__q.comp)) { }
556#endif
557
558 /**
559 * @brief Builds a %queue from a range.
560 * @param __first An input iterator.
561 * @param __last An input iterator.
562 * @param __x A comparison functor describing a strict weak ordering.
563 * @param __s An initial sequence with which to start.
564 *
565 * Begins by copying @a __s, inserting a copy of the elements
566 * from @a [first,last) into the copy of @a __s, then ordering
567 * the copy according to @a __x.
568 *
569 * For more information on function objects, see the
570 * documentation on @link functors functor base
571 * classes@endlink.
572 */
573#if __cplusplus < 201103L
574 template<typename _InputIterator>
575 priority_queue(_InputIterator __first, _InputIterator __last,
576 const _Compare& __x = _Compare(),
577 const _Sequence& __s = _Sequence())
578 : c(__s), comp(__x)
579 {
580 __glibcxx_requires_valid_range(__first, __last);
581 c.insert(c.end(), __first, __last);
582 std::make_heap(c.begin(), c.end(), comp);
583 }
584#else
585 template<typename _InputIterator>
586 priority_queue(_InputIterator __first, _InputIterator __last,
587 const _Compare& __x,
588 const _Sequence& __s)
589 : c(__s), comp(__x)
590 {
591 __glibcxx_requires_valid_range(__first, __last);
592 c.insert(c.end(), __first, __last);
593 std::make_heap(c.begin(), c.end(), comp);
594 }
595
596 template<typename _InputIterator>
597 priority_queue(_InputIterator __first, _InputIterator __last,
598 const _Compare& __x = _Compare(),
599 _Sequence&& __s = _Sequence())
600 : c(std::move(__s)), comp(__x)
601 {
602 __glibcxx_requires_valid_range(__first, __last);
603 c.insert(c.end(), __first, __last);
604 std::make_heap(c.begin(), c.end(), comp);
605 }
606#endif
607
608 /**
609 * Returns true if the %queue is empty.
610 */
611 _GLIBCXX_NODISCARD bool
612 empty() const
613 { return c.empty(); }
614
615 /** Returns the number of elements in the %queue. */
616 size_type
617 size() const
618 { return c.size(); }
619
620 /**
621 * Returns a read-only (constant) reference to the data at the first
622 * element of the %queue.
623 */
624 const_reference
625 top() const
626 {
627 __glibcxx_requires_nonempty();
628 return c.front();
629 }
630
631 /**
632 * @brief Add data to the %queue.
633 * @param __x Data to be added.
634 *
635 * This is a typical %queue operation.
636 * The time complexity of the operation depends on the underlying
637 * sequence.
638 */
639 void
640 push(const value_type& __x)
641 {
642 c.push_back(__x);
643 std::push_heap(c.begin(), c.end(), comp);
644 }
645
646#if __cplusplus >= 201103L
647 void
648 push(value_type&& __x)
649 {
650 c.push_back(std::move(__x));
651 std::push_heap(c.begin(), c.end(), comp);
652 }
653
654 template<typename... _Args>
655 void
656 emplace(_Args&&... __args)
657 {
658 c.emplace_back(std::forward<_Args>(__args)...);
659 std::push_heap(c.begin(), c.end(), comp);
660 }
661#endif
662
663 /**
664 * @brief Removes first element.
665 *
666 * This is a typical %queue operation. It shrinks the %queue
667 * by one. The time complexity of the operation depends on the
668 * underlying sequence.
669 *
670 * Note that no data is returned, and if the first element's
671 * data is needed, it should be retrieved before pop() is
672 * called.
673 */
674 void
675 pop()
676 {
677 __glibcxx_requires_nonempty();
678 std::pop_heap(c.begin(), c.end(), comp);
679 c.pop_back();
680 }
681
682#if __cplusplus >= 201103L
683 void
684 swap(priority_queue& __pq)
685 noexcept(__and_<
686#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
687 __is_nothrow_swappable<_Sequence>,
688#else
689 __is_nothrow_swappable<_Tp>,
690#endif
691 __is_nothrow_swappable<_Compare>
692 >::value)
693 {
694 using std::swap;
695 swap(c, __pq.c);
696 swap(comp, __pq.comp);
697 }
698#endif // __cplusplus >= 201103L
699 };
700
701#if __cpp_deduction_guides >= 201606
702 template<typename _Compare, typename _Container,
703 typename = _RequireNotAllocator<_Compare>,
704 typename = _RequireNotAllocator<_Container>>
705 priority_queue(_Compare, _Container)
706 -> priority_queue<typename _Container::value_type, _Container, _Compare>;
707
708 template<typename _InputIterator, typename _ValT
709 = typename iterator_traits<_InputIterator>::value_type,
710 typename _Compare = less<_ValT>,
711 typename _Container = vector<_ValT>,
712 typename = _RequireInputIter<_InputIterator>,
713 typename = _RequireNotAllocator<_Compare>,
714 typename = _RequireNotAllocator<_Container>>
715 priority_queue(_InputIterator, _InputIterator, _Compare = _Compare(),
716 _Container = _Container())
717 -> priority_queue<_ValT, _Container, _Compare>;
718
719 template<typename _Compare, typename _Container, typename _Allocator,
720 typename = _RequireNotAllocator<_Compare>,
721 typename = _RequireNotAllocator<_Container>,
722 typename = _RequireAllocator<_Allocator>>
723 priority_queue(_Compare, _Container, _Allocator)
724 -> priority_queue<typename _Container::value_type, _Container, _Compare>;
725#endif
726
727 // No equality/comparison operators are provided for priority_queue.
728
729#if __cplusplus >= 201103L
730 template<typename _Tp, typename _Sequence, typename _Compare>
731 inline
732#if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11
733 // Constrained free swap overload, see p0185r1
734 typename enable_if<__and_<__is_swappable<_Sequence>,
735 __is_swappable<_Compare>>::value>::type
736#else
737 void
738#endif
739 swap(priority_queue<_Tp, _Sequence, _Compare>& __x,
740 priority_queue<_Tp, _Sequence, _Compare>& __y)
741 noexcept(noexcept(__x.swap(__y)))
742 { __x.swap(__y); }
743
744 template<typename _Tp, typename _Sequence, typename _Compare,
745 typename _Alloc>
746 struct uses_allocator<priority_queue<_Tp, _Sequence, _Compare>, _Alloc>
747 : public uses_allocator<_Sequence, _Alloc>::type { };
748#endif // __cplusplus >= 201103L
749
750_GLIBCXX_END_NAMESPACE_VERSION
751} // namespace
752
753#endif /* _STL_QUEUE_H */
754