xref: /freebsd/contrib/llvm-project/libcxx/include/unordered_map (revision 9c77fb6aaa366cbabc80ee1b834bcfe4df135491)
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_UNORDERED_MAP
11#define _LIBCPP_UNORDERED_MAP
12
13/*
14
15    unordered_map synopsis
16
17#include <initializer_list>
18
19namespace std
20{
21
22template <class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>,
23          class Alloc = allocator<pair<const Key, T>>>
24class unordered_map
25{
26public:
27    // types
28    typedef Key                                                        key_type;
29    typedef T                                                          mapped_type;
30    typedef Hash                                                       hasher;
31    typedef Pred                                                       key_equal;
32    typedef Alloc                                                      allocator_type;
33    typedef pair<const key_type, mapped_type>                          value_type;
34    typedef value_type&                                                reference;
35    typedef const value_type&                                          const_reference;
36    typedef typename allocator_traits<allocator_type>::pointer         pointer;
37    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
38    typedef typename allocator_traits<allocator_type>::size_type       size_type;
39    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
40
41    typedef /unspecified/ iterator;
42    typedef /unspecified/ const_iterator;
43    typedef /unspecified/ local_iterator;
44    typedef /unspecified/ const_local_iterator;
45
46    typedef unspecified                             node_type;            // C++17
47    typedef INSERT_RETURN_TYPE<iterator, node_type> insert_return_type;   // C++17
48
49    unordered_map()
50        noexcept(
51            is_nothrow_default_constructible<hasher>::value &&
52            is_nothrow_default_constructible<key_equal>::value &&
53            is_nothrow_default_constructible<allocator_type>::value);
54    explicit unordered_map(size_type n, const hasher& hf = hasher(),
55                           const key_equal& eql = key_equal(),
56                           const allocator_type& a = allocator_type());
57    template <class InputIterator>
58        unordered_map(InputIterator f, InputIterator l,
59                      size_type n = 0, const hasher& hf = hasher(),
60                      const key_equal& eql = key_equal(),
61                      const allocator_type& a = allocator_type());
62    template<container-compatible-range<value_type> R>
63      unordered_map(from_range_t, R&& rg, size_type n = see below,
64        const hasher& hf = hasher(), const key_equal& eql = key_equal(),
65        const allocator_type& a = allocator_type()); // C++23
66
67    explicit unordered_map(const allocator_type&);
68    unordered_map(const unordered_map&);
69    unordered_map(const unordered_map&, const Allocator&);
70    unordered_map(unordered_map&&)
71        noexcept(
72            is_nothrow_move_constructible<hasher>::value &&
73            is_nothrow_move_constructible<key_equal>::value &&
74            is_nothrow_move_constructible<allocator_type>::value);
75    unordered_map(unordered_map&&, const Allocator&);
76    unordered_map(initializer_list<value_type>, size_type n = 0,
77                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
78                  const allocator_type& a = allocator_type());
79    unordered_map(size_type n, const allocator_type& a)
80      : unordered_map(n, hasher(), key_equal(), a) {}  // C++14
81    unordered_map(size_type n, const hasher& hf, const allocator_type& a)
82      : unordered_map(n, hf, key_equal(), a) {}  // C++14
83    template <class InputIterator>
84      unordered_map(InputIterator f, InputIterator l, size_type n, const allocator_type& a)
85      : unordered_map(f, l, n, hasher(), key_equal(), a) {}  // C++14
86    template <class InputIterator>
87      unordered_map(InputIterator f, InputIterator l, size_type n, const hasher& hf,
88        const allocator_type& a)
89      : unordered_map(f, l, n, hf, key_equal(), a) {}  // C++14
90    template<container-compatible-range<value_type> R>
91      unordered_map(from_range_t, R&& rg, size_type n, const allocator_type& a)
92        : unordered_map(from_range, std::forward<R>(rg), n, hasher(), key_equal(), a) { } // C++23
93    template<container-compatible-range<value_type> R>
94      unordered_map(from_range_t, R&& rg, size_type n, const hasher& hf, const allocator_type& a)
95        : unordered_map(from_range, std::forward<R>(rg), n, hf, key_equal(), a) { }       // C++23
96    unordered_map(initializer_list<value_type> il, size_type n, const allocator_type& a)
97      : unordered_map(il, n, hasher(), key_equal(), a) {}  // C++14
98    unordered_map(initializer_list<value_type> il, size_type n, const hasher& hf,
99      const allocator_type& a)
100      : unordered_map(il, n, hf, key_equal(), a) {}  // C++14
101    ~unordered_map();
102    unordered_map& operator=(const unordered_map&);
103    unordered_map& operator=(unordered_map&&)
104        noexcept(
105            allocator_type::propagate_on_container_move_assignment::value &&
106            is_nothrow_move_assignable<allocator_type>::value &&
107            is_nothrow_move_assignable<hasher>::value &&
108            is_nothrow_move_assignable<key_equal>::value);
109    unordered_map& operator=(initializer_list<value_type>);
110
111    allocator_type get_allocator() const noexcept;
112
113    bool      empty() const noexcept;
114    size_type size() const noexcept;
115    size_type max_size() const noexcept;
116
117    iterator       begin() noexcept;
118    iterator       end() noexcept;
119    const_iterator begin()  const noexcept;
120    const_iterator end()    const noexcept;
121    const_iterator cbegin() const noexcept;
122    const_iterator cend()   const noexcept;
123
124    template <class... Args>
125        pair<iterator, bool> emplace(Args&&... args);
126    template <class... Args>
127        iterator emplace_hint(const_iterator position, Args&&... args);
128    pair<iterator, bool> insert(const value_type& obj);
129    template <class P>
130        pair<iterator, bool> insert(P&& obj);
131    iterator insert(const_iterator hint, const value_type& obj);
132    template <class P>
133        iterator insert(const_iterator hint, P&& obj);
134    template <class InputIterator>
135        void insert(InputIterator first, InputIterator last);
136    template<container-compatible-range<value_type> R>
137      void insert_range(R&& rg);                                                      // C++23
138    void insert(initializer_list<value_type>);
139
140    node_type extract(const_iterator position);                                       // C++17
141    node_type extract(const key_type& x);                                             // C++17
142    insert_return_type insert(node_type&& nh);                                        // C++17
143    iterator           insert(const_iterator hint, node_type&& nh);                   // C++17
144
145    template <class... Args>
146        pair<iterator, bool> try_emplace(const key_type& k, Args&&... args);          // C++17
147    template <class... Args>
148        pair<iterator, bool> try_emplace(key_type&& k, Args&&... args);               // C++17
149    template <class... Args>
150        iterator try_emplace(const_iterator hint, const key_type& k, Args&&... args); // C++17
151    template <class... Args>
152        iterator try_emplace(const_iterator hint, key_type&& k, Args&&... args);      // C++17
153    template <class M>
154        pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj);            // C++17
155    template <class M>
156        pair<iterator, bool> insert_or_assign(key_type&& k, M&& obj);                 // C++17
157    template <class M>
158        iterator insert_or_assign(const_iterator hint, const key_type& k, M&& obj);   // C++17
159    template <class M>
160        iterator insert_or_assign(const_iterator hint, key_type&& k, M&& obj);        // C++17
161
162    iterator erase(const_iterator position);
163    iterator erase(iterator position);  // C++14
164    size_type erase(const key_type& k);
165    iterator erase(const_iterator first, const_iterator last);
166    void clear() noexcept;
167
168    template<class H2, class P2>
169      void merge(unordered_map<Key, T, H2, P2, Allocator>& source);         // C++17
170    template<class H2, class P2>
171      void merge(unordered_map<Key, T, H2, P2, Allocator>&& source);        // C++17
172    template<class H2, class P2>
173      void merge(unordered_multimap<Key, T, H2, P2, Allocator>& source);    // C++17
174    template<class H2, class P2>
175      void merge(unordered_multimap<Key, T, H2, P2, Allocator>&& source);   // C++17
176
177    void swap(unordered_map&)
178        noexcept(
179            (!allocator_type::propagate_on_container_swap::value ||
180             __is_nothrow_swappable<allocator_type>::value) &&
181            __is_nothrow_swappable<hasher>::value &&
182            __is_nothrow_swappable<key_equal>::value);
183
184    hasher hash_function() const;
185    key_equal key_eq() const;
186
187    iterator       find(const key_type& k);
188    const_iterator find(const key_type& k) const;
189    template<typename K>
190        iterator find(const K& x);              // C++20
191    template<typename K>
192        const_iterator find(const K& x) const;  // C++20
193    size_type count(const key_type& k) const;
194    template<typename K>
195        size_type count(const K& k) const; // C++20
196    bool contains(const key_type& k) const; // C++20
197    template<typename K>
198        bool contains(const K& k) const; // C++20
199    pair<iterator, iterator>             equal_range(const key_type& k);
200    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
201    template<typename K>
202        pair<iterator, iterator>             equal_range(const K& k); // C++20
203    template<typename K>
204        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20
205
206    mapped_type& operator[](const key_type& k);
207    mapped_type& operator[](key_type&& k);
208
209    mapped_type&       at(const key_type& k);
210    const mapped_type& at(const key_type& k) const;
211
212    size_type bucket_count() const noexcept;
213    size_type max_bucket_count() const noexcept;
214
215    size_type bucket_size(size_type n) const;
216    size_type bucket(const key_type& k) const;
217
218    local_iterator       begin(size_type n);
219    local_iterator       end(size_type n);
220    const_local_iterator begin(size_type n) const;
221    const_local_iterator end(size_type n) const;
222    const_local_iterator cbegin(size_type n) const;
223    const_local_iterator cend(size_type n) const;
224
225    float load_factor() const noexcept;
226    float max_load_factor() const noexcept;
227    void max_load_factor(float z);
228    void rehash(size_type n);
229    void reserve(size_type n);
230};
231
232template<class InputIterator,
233    class Hash = hash<iter_key_t<InputIterator>>, class Pred = equal_to<iter_key_t<InputIterator>>,
234    class Allocator = allocator<iter_to_alloc_t<InputIterator>>>
235unordered_map(InputIterator, InputIterator, typename see below::size_type = see below,
236    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
237  -> unordered_map<iter_key_t<InputIterator>, iter_value_t<InputIterator>, Hash, Pred,
238    Allocator>; // C++17
239
240template<ranges::input_range R, class Hash = hash<range-key-type<R>>,
241         class Pred = equal_to<range-key-type<R>>,
242         class Allocator = allocator<range-to-alloc-type<R>>>
243  unordered_map(from_range_t, R&&, typename see below::size_type = see below,
244                Hash = Hash(), Pred = Pred(), Allocator = Allocator())
245    -> unordered_map<range-key-type<R>, range-mapped-type<R>, Hash, Pred, Allocator>; // C++23
246
247template<class Key, class T, class Hash = hash<Key>,
248    class Pred = equal_to<Key>, class Allocator = allocator<pair<const Key, T>>>
249unordered_map(initializer_list<pair<const Key, T>>, typename see below::size_type = see below,
250    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
251  -> unordered_map<Key, T, Hash, Pred, Allocator>; // C++17
252
253template<class InputIterator, class Allocator>
254unordered_map(InputIterator, InputIterator, typename see below::size_type, Allocator)
255  -> unordered_map<iter_key_t<InputIterator>, iter_val_t<InputIterator>,
256        hash<iter_key_t<InputIterator>>, equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17
257
258template<class InputIterator, class Allocator>
259unordered_map(InputIterator, InputIterator, Allocator)
260  -> unordered_map<iter_key_t<InputIterator>, iter_val_t<InputIterator>,
261        hash<iter_key_t<InputIterator>>, equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17
262
263template<class InputIterator, class Hash, class Allocator>
264unordered_map(InputIterator, InputIterator, typename see below::size_type, Hash, Allocator)
265  -> unordered_map<iter_key_t<InputIterator>, iter_val_t<InputIterator>, Hash,
266          equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17
267
268template<ranges::input_range R, class Allocator>
269  unordered_map(from_range_t, R&&, typename see below::size_type, Allocator)
270    -> unordered_map<range-key-type<R>, range-mapped-type<R>, hash<range-key-type<R>>,
271                      equal_to<range-key-type<R>>, Allocator>;   // C++23
272
273template<ranges::input_range R, class Allocator>
274  unordered_map(from_range_t, R&&, Allocator)
275    -> unordered_map<range-key-type<R>, range-mapped-type<R>, hash<range-key-type<R>>,
276                      equal_to<range-key-type<R>>, Allocator>;   // C++23
277
278template<ranges::input_range R, class Hash, class Allocator>
279  unordered_map(from_range_t, R&&, typename see below::size_type, Hash, Allocator)
280    -> unordered_map<range-key-type<R>, range-mapped-type<R>, Hash,
281                      equal_to<range-key-type<R>>, Allocator>;   // C++23
282
283template<class Key, class T, typename Allocator>
284unordered_map(initializer_list<pair<const Key, T>>, typename see below::size_type, Allocator)
285  -> unordered_map<Key, T, hash<Key>, equal_to<Key>, Allocator>; // C++17
286
287template<class Key, class T, typename Allocator>
288unordered_map(initializer_list<pair<const Key, T>>, Allocator)
289  -> unordered_map<Key, T, hash<Key>, equal_to<Key>, Allocator>; // C++17
290
291template<class Key, class T, class Hash, class Allocator>
292unordered_map(initializer_list<pair<const Key, T>>, typename see below::size_type, Hash, Allocator)
293  -> unordered_map<Key, T, Hash, equal_to<Key>, Allocator>; // C++17
294
295template <class Key, class T, class Hash, class Pred, class Alloc>
296    void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x,
297              unordered_map<Key, T, Hash, Pred, Alloc>& y)
298              noexcept(noexcept(x.swap(y)));
299
300template <class Key, class T, class Hash, class Pred, class Alloc>
301    bool
302    operator==(const unordered_map<Key, T, Hash, Pred, Alloc>& x,
303               const unordered_map<Key, T, Hash, Pred, Alloc>& y);
304
305template <class Key, class T, class Hash, class Pred, class Alloc>
306    bool
307    operator!=(const unordered_map<Key, T, Hash, Pred, Alloc>& x,
308               const unordered_map<Key, T, Hash, Pred, Alloc>& y); // Removed in C++20
309
310template <class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>,
311          class Alloc = allocator<pair<const Key, T>>>
312class unordered_multimap
313{
314public:
315    // types
316    typedef Key                                                        key_type;
317    typedef T                                                          mapped_type;
318    typedef Hash                                                       hasher;
319    typedef Pred                                                       key_equal;
320    typedef Alloc                                                      allocator_type;
321    typedef pair<const key_type, mapped_type>                          value_type;
322    typedef value_type&                                                reference;
323    typedef const value_type&                                          const_reference;
324    typedef typename allocator_traits<allocator_type>::pointer         pointer;
325    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
326    typedef typename allocator_traits<allocator_type>::size_type       size_type;
327    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
328
329    typedef /unspecified/ iterator;
330    typedef /unspecified/ const_iterator;
331    typedef /unspecified/ local_iterator;
332    typedef /unspecified/ const_local_iterator;
333
334    typedef unspecified node_type;    // C++17
335
336    unordered_multimap()
337        noexcept(
338            is_nothrow_default_constructible<hasher>::value &&
339            is_nothrow_default_constructible<key_equal>::value &&
340            is_nothrow_default_constructible<allocator_type>::value);
341    explicit unordered_multimap(size_type n, const hasher& hf = hasher(),
342                           const key_equal& eql = key_equal(),
343                           const allocator_type& a = allocator_type());
344    template <class InputIterator>
345        unordered_multimap(InputIterator f, InputIterator l,
346                      size_type n = 0, const hasher& hf = hasher(),
347                      const key_equal& eql = key_equal(),
348                      const allocator_type& a = allocator_type());
349    template<container-compatible-range<value_type> R>
350      unordered_multimap(from_range_t, R&& rg, size_type n = see below,
351        const hasher& hf = hasher(), const key_equal& eql = key_equal(),
352        const allocator_type& a = allocator_type()); // C++23
353    explicit unordered_multimap(const allocator_type&);
354    unordered_multimap(const unordered_multimap&);
355    unordered_multimap(const unordered_multimap&, const Allocator&);
356    unordered_multimap(unordered_multimap&&)
357        noexcept(
358            is_nothrow_move_constructible<hasher>::value &&
359            is_nothrow_move_constructible<key_equal>::value &&
360            is_nothrow_move_constructible<allocator_type>::value);
361    unordered_multimap(unordered_multimap&&, const Allocator&);
362    unordered_multimap(initializer_list<value_type>, size_type n = 0,
363                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
364                  const allocator_type& a = allocator_type());
365    unordered_multimap(size_type n, const allocator_type& a)
366      : unordered_multimap(n, hasher(), key_equal(), a) {}  // C++14
367    unordered_multimap(size_type n, const hasher& hf, const allocator_type& a)
368      : unordered_multimap(n, hf, key_equal(), a) {}  // C++14
369    template <class InputIterator>
370      unordered_multimap(InputIterator f, InputIterator l, size_type n, const allocator_type& a)
371      : unordered_multimap(f, l, n, hasher(), key_equal(), a) {}  // C++14
372    template <class InputIterator>
373      unordered_multimap(InputIterator f, InputIterator l, size_type n, const hasher& hf,
374        const allocator_type& a)
375      : unordered_multimap(f, l, n, hf, key_equal(), a) {}  // C++14
376    template<container-compatible-range<value_type> R>
377      unordered_multimap(from_range_t, R&& rg, size_type n, const allocator_type& a)
378        : unordered_multimap(from_range, std::forward<R>(rg), n, hasher(), key_equal(), a) { } // C++23
379    template<container-compatible-range<value_type> R>
380      unordered_multimap(from_range_t, R&& rg, size_type n, const hasher& hf, const allocator_type& a)
381        : unordered_multimap(from_range, std::forward<R>(rg), n, hf, key_equal(), a) { }       // C++23
382    unordered_multimap(initializer_list<value_type> il, size_type n, const allocator_type& a)
383      : unordered_multimap(il, n, hasher(), key_equal(), a) {}  // C++14
384    unordered_multimap(initializer_list<value_type> il, size_type n, const hasher& hf,
385      const allocator_type& a)
386      : unordered_multimap(il, n, hf, key_equal(), a) {}  // C++14
387    ~unordered_multimap();
388    unordered_multimap& operator=(const unordered_multimap&);
389    unordered_multimap& operator=(unordered_multimap&&)
390        noexcept(
391            allocator_type::propagate_on_container_move_assignment::value &&
392            is_nothrow_move_assignable<allocator_type>::value &&
393            is_nothrow_move_assignable<hasher>::value &&
394            is_nothrow_move_assignable<key_equal>::value);
395    unordered_multimap& operator=(initializer_list<value_type>);
396
397    allocator_type get_allocator() const noexcept;
398
399    bool      empty() const noexcept;
400    size_type size() const noexcept;
401    size_type max_size() const noexcept;
402
403    iterator       begin() noexcept;
404    iterator       end() noexcept;
405    const_iterator begin()  const noexcept;
406    const_iterator end()    const noexcept;
407    const_iterator cbegin() const noexcept;
408    const_iterator cend()   const noexcept;
409
410    template <class... Args>
411        iterator emplace(Args&&... args);
412    template <class... Args>
413        iterator emplace_hint(const_iterator position, Args&&... args);
414    iterator insert(const value_type& obj);
415    template <class P>
416        iterator insert(P&& obj);
417    iterator insert(const_iterator hint, const value_type& obj);
418    template <class P>
419        iterator insert(const_iterator hint, P&& obj);
420    template <class InputIterator>
421        void insert(InputIterator first, InputIterator last);
422    template<container-compatible-range<value_type> R>
423      void insert_range(R&& rg);                               // C++23
424    void insert(initializer_list<value_type>);
425
426    node_type extract(const_iterator position);                // C++17
427    node_type extract(const key_type& x);                      // C++17
428    iterator insert(node_type&& nh);                           // C++17
429    iterator insert(const_iterator hint, node_type&& nh);      // C++17
430
431    iterator erase(const_iterator position);
432    iterator erase(iterator position);  // C++14
433    size_type erase(const key_type& k);
434    iterator erase(const_iterator first, const_iterator last);
435    void clear() noexcept;
436
437    template<class H2, class P2>
438      void merge(unordered_multimap<Key, T, H2, P2, Allocator>& source);    // C++17
439    template<class H2, class P2>
440      void merge(unordered_multimap<Key, T, H2, P2, Allocator>&& source);   // C++17
441    template<class H2, class P2>
442      void merge(unordered_map<Key, T, H2, P2, Allocator>& source);         // C++17
443    template<class H2, class P2>
444      void merge(unordered_map<Key, T, H2, P2, Allocator>&& source);        // C++17
445
446    void swap(unordered_multimap&)
447        noexcept(
448            (!allocator_type::propagate_on_container_swap::value ||
449             __is_nothrow_swappable<allocator_type>::value) &&
450            __is_nothrow_swappable<hasher>::value &&
451            __is_nothrow_swappable<key_equal>::value);
452
453    hasher hash_function() const;
454    key_equal key_eq() const;
455
456    iterator       find(const key_type& k);
457    const_iterator find(const key_type& k) const;
458    template<typename K>
459        iterator find(const K& x);              // C++20
460    template<typename K>
461        const_iterator find(const K& x) const;  // C++20
462    size_type count(const key_type& k) const;
463    template<typename K>
464        size_type count(const K& k) const; // C++20
465    bool contains(const key_type& k) const; // C++20
466    template<typename K>
467        bool contains(const K& k) const; // C++20
468    pair<iterator, iterator>             equal_range(const key_type& k);
469    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
470    template<typename K>
471        pair<iterator, iterator>             equal_range(const K& k); // C++20
472    template<typename K>
473        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20
474
475    size_type bucket_count() const noexcept;
476    size_type max_bucket_count() const noexcept;
477
478    size_type bucket_size(size_type n) const;
479    size_type bucket(const key_type& k) const;
480
481    local_iterator       begin(size_type n);
482    local_iterator       end(size_type n);
483    const_local_iterator begin(size_type n) const;
484    const_local_iterator end(size_type n) const;
485    const_local_iterator cbegin(size_type n) const;
486    const_local_iterator cend(size_type n) const;
487
488    float load_factor() const noexcept;
489    float max_load_factor() const noexcept;
490    void max_load_factor(float z);
491    void rehash(size_type n);
492    void reserve(size_type n);
493};
494
495template<class InputIterator,
496    class Hash = hash<iter_key_t<InputIterator>>, class Pred = equal_to<iter_key_t<InputIterator>>,
497    class Allocator = allocator<iter_to_alloc_t<InputIterator>>>
498unordered_multimap(InputIterator, InputIterator, typename see below::size_type = see below,
499    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
500  -> unordered_multimap<iter_key_t<InputIterator>, iter_value_t<InputIterator>, Hash, Pred,
501    Allocator>; // C++17
502
503template<ranges::input_range R, class Hash = hash<range-key-type<R>>,
504         class Pred = equal_to<range-key-type<R>>,
505         class Allocator = allocator<range-to-alloc-type<R>>>
506  unordered_multimap(from_range_t, R&&, typename see below::size_type = see below,
507                Hash = Hash(), Pred = Pred(), Allocator = Allocator())
508    -> unordered_multimap<range-key-type<R>, range-mapped-type<R>, Hash, Pred, Allocator>; // C++23
509
510template<class Key, class T, class Hash = hash<Key>,
511    class Pred = equal_to<Key>, class Allocator = allocator<pair<const Key, T>>>
512unordered_multimap(initializer_list<pair<const Key, T>>, typename see below::size_type = see below,
513    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
514  -> unordered_multimap<Key, T, Hash, Pred, Allocator>; // C++17
515
516template<class InputIterator, class Allocator>
517unordered_multimap(InputIterator, InputIterator, typename see below::size_type, Allocator)
518  -> unordered_multimap<iter_key_t<InputIterator>, iter_val_t<InputIterator>,
519        hash<iter_key_t<InputIterator>>, equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17
520
521template<class InputIterator, class Allocator>
522unordered_multimap(InputIterator, InputIterator, Allocator)
523  -> unordered_multimap<iter_key_t<InputIterator>, iter_val_t<InputIterator>,
524        hash<iter_key_t<InputIterator>>, equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17
525
526template<class InputIterator, class Hash, class Allocator>
527unordered_multimap(InputIterator, InputIterator, typename see below::size_type, Hash, Allocator)
528  -> unordered_multimap<iter_key_t<InputIterator>, iter_val_t<InputIterator>, Hash,
529          equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17
530
531template<ranges::input_range R, class Allocator>
532  unordered_multimap(from_range_t, R&&, typename see below::size_type, Allocator)
533    -> unordered_multimap<range-key-type<R>, range-mapped-type<R>, hash<range-key-type<R>>,
534                      equal_to<range-key-type<R>>, Allocator>;   // C++23
535
536template<ranges::input_range R, class Allocator>
537  unordered_multimap(from_range_t, R&&, Allocator)
538    -> unordered_multimap<range-key-type<R>, range-mapped-type<R>, hash<range-key-type<R>>,
539                      equal_to<range-key-type<R>>, Allocator>;   // C++23
540
541template<ranges::input_range R, class Hash, class Allocator>
542  unordered_multimap(from_range_t, R&&, typename see below::size_type, Hash, Allocator)
543    -> unordered_multimap<range-key-type<R>, range-mapped-type<R>, Hash,
544                      equal_to<range-key-type<R>>, Allocator>;   // C++23
545
546template<class Key, class T, typename Allocator>
547unordered_multimap(initializer_list<pair<const Key, T>>, typename see below::size_type, Allocator)
548  -> unordered_multimap<Key, T, hash<Key>, equal_to<Key>, Allocator>; // C++17
549
550template<class Key, class T, typename Allocator>
551unordered_multimap(initializer_list<pair<const Key, T>>, Allocator)
552  -> unordered_multimap<Key, T, hash<Key>, equal_to<Key>, Allocator>; // C++17
553
554template<class Key, class T, class Hash, class Allocator>
555unordered_multimap(initializer_list<pair<const Key, T>>, typename see below::size_type, Hash,
556    Allocator)
557  -> unordered_multimap<Key, T, Hash, equal_to<Key>, Allocator>; // C++17
558
559template <class Key, class T, class Hash, class Pred, class Alloc>
560    void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
561              unordered_multimap<Key, T, Hash, Pred, Alloc>& y)
562              noexcept(noexcept(x.swap(y)));
563
564template <class K, class T, class H, class P, class A, class Predicate>
565    typename unordered_map<K, T, H, P, A>::size_type
566    erase_if(unordered_map<K, T, H, P, A>& c, Predicate pred);       // C++20
567
568template <class K, class T, class H, class P, class A, class Predicate>
569    typename unordered_multimap<K, T, H, P, A>::size_type
570    erase_if(unordered_multimap<K, T, H, P, A>& c, Predicate pred);  // C++20
571
572template <class Key, class T, class Hash, class Pred, class Alloc>
573    bool
574    operator==(const unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
575               const unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
576
577template <class Key, class T, class Hash, class Pred, class Alloc>
578    bool
579    operator!=(const unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
580               const unordered_multimap<Key, T, Hash, Pred, Alloc>& y); // Removed in C++20
581
582}  // std
583
584*/
585
586#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
587#  include <__cxx03/unordered_map>
588#else
589#  include <__algorithm/is_permutation.h>
590#  include <__assert>
591#  include <__config>
592#  include <__functional/hash.h>
593#  include <__functional/is_transparent.h>
594#  include <__functional/operations.h>
595#  include <__hash_table>
596#  include <__iterator/distance.h>
597#  include <__iterator/erase_if_container.h>
598#  include <__iterator/iterator_traits.h>
599#  include <__iterator/ranges_iterator_traits.h>
600#  include <__memory/addressof.h>
601#  include <__memory/allocator.h>
602#  include <__memory/allocator_traits.h>
603#  include <__memory/pointer_traits.h>
604#  include <__memory/unique_ptr.h>
605#  include <__memory_resource/polymorphic_allocator.h>
606#  include <__new/launder.h>
607#  include <__node_handle>
608#  include <__ranges/concepts.h>
609#  include <__ranges/container_compatible_range.h>
610#  include <__ranges/from_range.h>
611#  include <__type_traits/container_traits.h>
612#  include <__type_traits/enable_if.h>
613#  include <__type_traits/invoke.h>
614#  include <__type_traits/is_allocator.h>
615#  include <__type_traits/is_integral.h>
616#  include <__type_traits/remove_const.h>
617#  include <__type_traits/type_identity.h>
618#  include <__utility/forward.h>
619#  include <__utility/pair.h>
620#  include <stdexcept>
621#  include <tuple>
622#  include <version>
623
624// standard-mandated includes
625
626// [iterator.range]
627#  include <__iterator/access.h>
628#  include <__iterator/data.h>
629#  include <__iterator/empty.h>
630#  include <__iterator/reverse_access.h>
631#  include <__iterator/size.h>
632
633// [unord.map.syn]
634#  include <compare>
635#  include <initializer_list>
636
637#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
638#    pragma GCC system_header
639#  endif
640
641_LIBCPP_PUSH_MACROS
642#  include <__undef_macros>
643
644_LIBCPP_BEGIN_NAMESPACE_STD
645
646template <class _Key,
647          class _Cp,
648          class _Hash,
649          class _Pred,
650          bool = is_empty<_Hash>::value && !__libcpp_is_final<_Hash>::value>
651class __unordered_map_hasher : private _Hash {
652public:
653  _LIBCPP_HIDE_FROM_ABI __unordered_map_hasher() _NOEXCEPT_(is_nothrow_default_constructible<_Hash>::value) : _Hash() {}
654  _LIBCPP_HIDE_FROM_ABI __unordered_map_hasher(const _Hash& __h) _NOEXCEPT_(is_nothrow_copy_constructible<_Hash>::value)
655      : _Hash(__h) {}
656  _LIBCPP_HIDE_FROM_ABI const _Hash& hash_function() const _NOEXCEPT { return *this; }
657  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _Cp& __x) const { return static_cast<const _Hash&>(*this)(__x.first); }
658  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _Key& __x) const { return static_cast<const _Hash&>(*this)(__x); }
659#  if _LIBCPP_STD_VER >= 20
660  template <typename _K2>
661  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _K2& __x) const {
662    return static_cast<const _Hash&>(*this)(__x);
663  }
664#  endif
665  _LIBCPP_HIDE_FROM_ABI void swap(__unordered_map_hasher& __y) _NOEXCEPT_(__is_nothrow_swappable_v<_Hash>) {
666    using std::swap;
667    swap(static_cast<_Hash&>(*this), static_cast<_Hash&>(__y));
668  }
669};
670
671template <class _Key, class _Cp, class _Hash, class _Pred>
672class __unordered_map_hasher<_Key, _Cp, _Hash, _Pred, false> {
673  _Hash __hash_;
674
675public:
676  _LIBCPP_HIDE_FROM_ABI __unordered_map_hasher() _NOEXCEPT_(is_nothrow_default_constructible<_Hash>::value)
677      : __hash_() {}
678  _LIBCPP_HIDE_FROM_ABI __unordered_map_hasher(const _Hash& __h) _NOEXCEPT_(is_nothrow_copy_constructible<_Hash>::value)
679      : __hash_(__h) {}
680  _LIBCPP_HIDE_FROM_ABI const _Hash& hash_function() const _NOEXCEPT { return __hash_; }
681  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _Cp& __x) const { return __hash_(__x.first); }
682  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _Key& __x) const { return __hash_(__x); }
683#  if _LIBCPP_STD_VER >= 20
684  template <typename _K2>
685  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _K2& __x) const {
686    return __hash_(__x);
687  }
688#  endif
689  _LIBCPP_HIDE_FROM_ABI void swap(__unordered_map_hasher& __y) _NOEXCEPT_(__is_nothrow_swappable_v<_Hash>) {
690    using std::swap;
691    swap(__hash_, __y.__hash_);
692  }
693};
694
695template <class _Key, class _Cp, class _Hash, class _Pred, bool __b>
696inline _LIBCPP_HIDE_FROM_ABI void
697swap(__unordered_map_hasher<_Key, _Cp, _Hash, _Pred, __b>& __x,
698     __unordered_map_hasher<_Key, _Cp, _Hash, _Pred, __b>& __y) _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
699  __x.swap(__y);
700}
701
702template <class _Key,
703          class _Cp,
704          class _Pred,
705          class _Hash,
706          bool = is_empty<_Pred>::value && !__libcpp_is_final<_Pred>::value>
707class __unordered_map_equal : private _Pred {
708public:
709  _LIBCPP_HIDE_FROM_ABI __unordered_map_equal() _NOEXCEPT_(is_nothrow_default_constructible<_Pred>::value) : _Pred() {}
710  _LIBCPP_HIDE_FROM_ABI __unordered_map_equal(const _Pred& __p) _NOEXCEPT_(is_nothrow_copy_constructible<_Pred>::value)
711      : _Pred(__p) {}
712  _LIBCPP_HIDE_FROM_ABI const _Pred& key_eq() const _NOEXCEPT { return *this; }
713  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _Cp& __y) const {
714    return static_cast<const _Pred&>(*this)(__x.first, __y.first);
715  }
716  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _Key& __y) const {
717    return static_cast<const _Pred&>(*this)(__x.first, __y);
718  }
719  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Key& __x, const _Cp& __y) const {
720    return static_cast<const _Pred&>(*this)(__x, __y.__get_value().first);
721  }
722#  if _LIBCPP_STD_VER >= 20
723  template <typename _K2>
724  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _K2& __y) const {
725    return static_cast<const _Pred&>(*this)(__x.first, __y);
726  }
727  template <typename _K2>
728  _LIBCPP_HIDE_FROM_ABI bool operator()(const _K2& __x, const _Cp& __y) const {
729    return static_cast<const _Pred&>(*this)(__x, __y.__get_value().first);
730  }
731  template <typename _K2>
732  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Key& __x, const _K2& __y) const {
733    return static_cast<const _Pred&>(*this)(__x, __y);
734  }
735  template <typename _K2>
736  _LIBCPP_HIDE_FROM_ABI bool operator()(const _K2& __x, const _Key& __y) const {
737    return static_cast<const _Pred&>(*this)(__x, __y);
738  }
739#  endif
740  _LIBCPP_HIDE_FROM_ABI void swap(__unordered_map_equal& __y) _NOEXCEPT_(__is_nothrow_swappable_v<_Pred>) {
741    using std::swap;
742    swap(static_cast<_Pred&>(*this), static_cast<_Pred&>(__y));
743  }
744};
745
746template <class _Key, class _Cp, class _Pred, class _Hash>
747class __unordered_map_equal<_Key, _Cp, _Pred, _Hash, false> {
748  _Pred __pred_;
749
750public:
751  _LIBCPP_HIDE_FROM_ABI __unordered_map_equal() _NOEXCEPT_(is_nothrow_default_constructible<_Pred>::value)
752      : __pred_() {}
753  _LIBCPP_HIDE_FROM_ABI __unordered_map_equal(const _Pred& __p) _NOEXCEPT_(is_nothrow_copy_constructible<_Pred>::value)
754      : __pred_(__p) {}
755  _LIBCPP_HIDE_FROM_ABI const _Pred& key_eq() const _NOEXCEPT { return __pred_; }
756  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _Cp& __y) const { return __pred_(__x.first, __y.first); }
757  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _Key& __y) const { return __pred_(__x.first, __y); }
758  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Key& __x, const _Cp& __y) const { return __pred_(__x, __y.first); }
759#  if _LIBCPP_STD_VER >= 20
760  template <typename _K2>
761  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _K2& __y) const {
762    return __pred_(__x.first, __y);
763  }
764  template <typename _K2>
765  _LIBCPP_HIDE_FROM_ABI bool operator()(const _K2& __x, const _Cp& __y) const {
766    return __pred_(__x, __y.first);
767  }
768  template <typename _K2>
769  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Key& __x, const _K2& __y) const {
770    return __pred_(__x, __y);
771  }
772  template <typename _K2>
773  _LIBCPP_HIDE_FROM_ABI bool operator()(const _K2& __x, const _Key& __y) const {
774    return __pred_(__x, __y);
775  }
776#  endif
777  _LIBCPP_HIDE_FROM_ABI void swap(__unordered_map_equal& __y) _NOEXCEPT_(__is_nothrow_swappable_v<_Pred>) {
778    using std::swap;
779    swap(__pred_, __y.__pred_);
780  }
781};
782
783template <class _Key, class _Cp, class _Pred, class _Hash, bool __b>
784inline _LIBCPP_HIDE_FROM_ABI void
785swap(__unordered_map_equal<_Key, _Cp, _Pred, _Hash, __b>& __x, __unordered_map_equal<_Key, _Cp, _Pred, _Hash, __b>& __y)
786    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
787  __x.swap(__y);
788}
789
790template <class _Alloc>
791class __hash_map_node_destructor {
792  typedef _Alloc allocator_type;
793  typedef allocator_traits<allocator_type> __alloc_traits;
794
795public:
796  typedef typename __alloc_traits::pointer pointer;
797
798private:
799  allocator_type& __na_;
800
801public:
802  bool __first_constructed;
803  bool __second_constructed;
804
805  __hash_map_node_destructor& operator=(const __hash_map_node_destructor&) = delete;
806
807  _LIBCPP_HIDE_FROM_ABI explicit __hash_map_node_destructor(allocator_type& __na) _NOEXCEPT
808      : __na_(__na),
809        __first_constructed(false),
810        __second_constructed(false) {}
811
812#  ifndef _LIBCPP_CXX03_LANG
813  _LIBCPP_HIDE_FROM_ABI __hash_map_node_destructor(__hash_node_destructor<allocator_type>&& __x) _NOEXCEPT
814      : __na_(__x.__na_),
815        __first_constructed(__x.__value_constructed),
816        __second_constructed(__x.__value_constructed) {
817    __x.__value_constructed = false;
818  }
819#  else  // _LIBCPP_CXX03_LANG
820  _LIBCPP_HIDE_FROM_ABI __hash_map_node_destructor(const __hash_node_destructor<allocator_type>& __x)
821      : __na_(__x.__na_), __first_constructed(__x.__value_constructed), __second_constructed(__x.__value_constructed) {
822    const_cast<bool&>(__x.__value_constructed) = false;
823  }
824#  endif // _LIBCPP_CXX03_LANG
825
826  _LIBCPP_HIDE_FROM_ABI void operator()(pointer __p) _NOEXCEPT {
827    if (__second_constructed)
828      __alloc_traits::destroy(__na_, std::addressof(__p->__get_value().second));
829    if (__first_constructed)
830      __alloc_traits::destroy(__na_, std::addressof(__p->__get_value().first));
831    if (__p)
832      __alloc_traits::deallocate(__na_, __p, 1);
833  }
834};
835
836template <class _Key, class _Tp>
837struct __hash_value_type;
838
839template <class _HashIterator>
840class __hash_map_iterator {
841  _HashIterator __i_;
842
843  typedef __hash_node_types_from_iterator<_HashIterator> _NodeTypes;
844
845public:
846  typedef forward_iterator_tag iterator_category;
847  typedef typename _NodeTypes::__map_value_type value_type;
848  typedef typename _NodeTypes::difference_type difference_type;
849  typedef value_type& reference;
850  typedef typename _NodeTypes::__map_value_type_pointer pointer;
851
852  _LIBCPP_HIDE_FROM_ABI __hash_map_iterator() _NOEXCEPT {}
853
854  _LIBCPP_HIDE_FROM_ABI __hash_map_iterator(_HashIterator __i) _NOEXCEPT : __i_(__i) {}
855
856  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return *__i_; }
857  _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return pointer_traits<pointer>::pointer_to(*__i_); }
858
859  _LIBCPP_HIDE_FROM_ABI __hash_map_iterator& operator++() {
860    ++__i_;
861    return *this;
862  }
863  _LIBCPP_HIDE_FROM_ABI __hash_map_iterator operator++(int) {
864    __hash_map_iterator __t(*this);
865    ++(*this);
866    return __t;
867  }
868
869  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __hash_map_iterator& __x, const __hash_map_iterator& __y) {
870    return __x.__i_ == __y.__i_;
871  }
872#  if _LIBCPP_STD_VER <= 17
873  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __hash_map_iterator& __x, const __hash_map_iterator& __y) {
874    return __x.__i_ != __y.__i_;
875  }
876#  endif
877
878  template <class, class, class, class, class>
879  friend class unordered_map;
880  template <class, class, class, class, class>
881  friend class unordered_multimap;
882  template <class>
883  friend class __hash_const_iterator;
884  template <class>
885  friend class __hash_const_local_iterator;
886  template <class>
887  friend class __hash_map_const_iterator;
888};
889
890template <class _HashIterator>
891class __hash_map_const_iterator {
892  _HashIterator __i_;
893
894  typedef __hash_node_types_from_iterator<_HashIterator> _NodeTypes;
895
896public:
897  typedef forward_iterator_tag iterator_category;
898  typedef typename _NodeTypes::__map_value_type value_type;
899  typedef typename _NodeTypes::difference_type difference_type;
900  typedef const value_type& reference;
901  typedef typename _NodeTypes::__const_map_value_type_pointer pointer;
902
903  _LIBCPP_HIDE_FROM_ABI __hash_map_const_iterator() _NOEXCEPT {}
904
905  _LIBCPP_HIDE_FROM_ABI __hash_map_const_iterator(_HashIterator __i) _NOEXCEPT : __i_(__i) {}
906  _LIBCPP_HIDE_FROM_ABI
907  __hash_map_const_iterator(__hash_map_iterator<typename _HashIterator::__non_const_iterator> __i) _NOEXCEPT
908      : __i_(__i.__i_) {}
909
910  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return *__i_; }
911  _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return pointer_traits<pointer>::pointer_to(*__i_); }
912
913  _LIBCPP_HIDE_FROM_ABI __hash_map_const_iterator& operator++() {
914    ++__i_;
915    return *this;
916  }
917  _LIBCPP_HIDE_FROM_ABI __hash_map_const_iterator operator++(int) {
918    __hash_map_const_iterator __t(*this);
919    ++(*this);
920    return __t;
921  }
922
923  friend _LIBCPP_HIDE_FROM_ABI bool
924  operator==(const __hash_map_const_iterator& __x, const __hash_map_const_iterator& __y) {
925    return __x.__i_ == __y.__i_;
926  }
927#  if _LIBCPP_STD_VER <= 17
928  friend _LIBCPP_HIDE_FROM_ABI bool
929  operator!=(const __hash_map_const_iterator& __x, const __hash_map_const_iterator& __y) {
930    return __x.__i_ != __y.__i_;
931  }
932#  endif
933
934  template <class, class, class, class, class>
935  friend class unordered_map;
936  template <class, class, class, class, class>
937  friend class unordered_multimap;
938  template <class>
939  friend class __hash_const_iterator;
940  template <class>
941  friend class __hash_const_local_iterator;
942};
943
944template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
945class unordered_multimap;
946
947template <class _Key,
948          class _Tp,
949          class _Hash  = hash<_Key>,
950          class _Pred  = equal_to<_Key>,
951          class _Alloc = allocator<pair<const _Key, _Tp> > >
952class unordered_map {
953public:
954  // types
955  typedef _Key key_type;
956  typedef _Tp mapped_type;
957  typedef __type_identity_t<_Hash> hasher;
958  typedef __type_identity_t<_Pred> key_equal;
959  typedef __type_identity_t<_Alloc> allocator_type;
960  typedef pair<const key_type, mapped_type> value_type;
961  typedef value_type& reference;
962  typedef const value_type& const_reference;
963  static_assert(is_same<value_type, typename allocator_type::value_type>::value,
964                "Allocator::value_type must be same type as value_type");
965
966private:
967  typedef __hash_value_type<key_type, mapped_type> __value_type;
968  typedef __unordered_map_hasher<key_type, value_type, hasher, key_equal> __hasher;
969  typedef __unordered_map_equal<key_type, value_type, key_equal, hasher> __key_equal;
970
971  typedef __hash_table<__value_type, __hasher, __key_equal, allocator_type> __table;
972
973  __table __table_;
974
975  typedef typename __table::_NodeTypes _NodeTypes;
976  typedef typename __table::__node_pointer __node_pointer;
977  typedef typename __table::__node_const_pointer __node_const_pointer;
978  typedef typename __table::__node_traits __node_traits;
979  typedef typename __table::__node_allocator __node_allocator;
980  typedef typename __table::__node __node;
981  typedef __hash_map_node_destructor<__node_allocator> _Dp;
982  typedef unique_ptr<__node, _Dp> __node_holder;
983  typedef allocator_traits<allocator_type> __alloc_traits;
984
985  static_assert(__check_valid_allocator<allocator_type>::value, "");
986
987public:
988  typedef typename __alloc_traits::pointer pointer;
989  typedef typename __alloc_traits::const_pointer const_pointer;
990  typedef typename __table::size_type size_type;
991  typedef typename __table::difference_type difference_type;
992
993  typedef __hash_map_iterator<typename __table::iterator> iterator;
994  typedef __hash_map_const_iterator<typename __table::const_iterator> const_iterator;
995  typedef __hash_map_iterator<typename __table::local_iterator> local_iterator;
996  typedef __hash_map_const_iterator<typename __table::const_local_iterator> const_local_iterator;
997
998#  if _LIBCPP_STD_VER >= 17
999  typedef __map_node_handle<__node, allocator_type> node_type;
1000  typedef __insert_return_type<iterator, node_type> insert_return_type;
1001#  endif
1002
1003  template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
1004  friend class unordered_map;
1005  template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
1006  friend class unordered_multimap;
1007
1008  _LIBCPP_HIDE_FROM_ABI unordered_map() _NOEXCEPT_(is_nothrow_default_constructible<__table>::value) {}
1009  explicit _LIBCPP_HIDE_FROM_ABI
1010  unordered_map(size_type __n, const hasher& __hf = hasher(), const key_equal& __eql = key_equal());
1011  _LIBCPP_HIDE_FROM_ABI
1012  unordered_map(size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a);
1013  template <class _InputIterator>
1014  _LIBCPP_HIDE_FROM_ABI unordered_map(_InputIterator __first, _InputIterator __last);
1015  template <class _InputIterator>
1016  _LIBCPP_HIDE_FROM_ABI
1017  unordered_map(_InputIterator __first,
1018                _InputIterator __last,
1019                size_type __n,
1020                const hasher& __hf     = hasher(),
1021                const key_equal& __eql = key_equal());
1022  template <class _InputIterator>
1023  _LIBCPP_HIDE_FROM_ABI unordered_map(
1024      _InputIterator __first,
1025      _InputIterator __last,
1026      size_type __n,
1027      const hasher& __hf,
1028      const key_equal& __eql,
1029      const allocator_type& __a);
1030
1031#  if _LIBCPP_STD_VER >= 23
1032  template <_ContainerCompatibleRange<value_type> _Range>
1033  _LIBCPP_HIDE_FROM_ABI unordered_map(
1034      from_range_t,
1035      _Range&& __range,
1036      size_type __n             = /*implementation-defined*/ 0,
1037      const hasher& __hf        = hasher(),
1038      const key_equal& __eql    = key_equal(),
1039      const allocator_type& __a = allocator_type())
1040      : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
1041    if (__n > 0) {
1042      __table_.__rehash_unique(__n);
1043    }
1044    insert_range(std::forward<_Range>(__range));
1045  }
1046#  endif
1047
1048  _LIBCPP_HIDE_FROM_ABI explicit unordered_map(const allocator_type& __a);
1049  _LIBCPP_HIDE_FROM_ABI unordered_map(const unordered_map& __u);
1050  _LIBCPP_HIDE_FROM_ABI unordered_map(const unordered_map& __u, const allocator_type& __a);
1051#  ifndef _LIBCPP_CXX03_LANG
1052  _LIBCPP_HIDE_FROM_ABI unordered_map(unordered_map&& __u) _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
1053  _LIBCPP_HIDE_FROM_ABI unordered_map(unordered_map&& __u, const allocator_type& __a);
1054  _LIBCPP_HIDE_FROM_ABI unordered_map(initializer_list<value_type> __il);
1055  _LIBCPP_HIDE_FROM_ABI
1056  unordered_map(initializer_list<value_type> __il,
1057                size_type __n,
1058                const hasher& __hf     = hasher(),
1059                const key_equal& __eql = key_equal());
1060  _LIBCPP_HIDE_FROM_ABI unordered_map(
1061      initializer_list<value_type> __il,
1062      size_type __n,
1063      const hasher& __hf,
1064      const key_equal& __eql,
1065      const allocator_type& __a);
1066#  endif // _LIBCPP_CXX03_LANG
1067#  if _LIBCPP_STD_VER >= 14
1068  _LIBCPP_HIDE_FROM_ABI unordered_map(size_type __n, const allocator_type& __a)
1069      : unordered_map(__n, hasher(), key_equal(), __a) {}
1070  _LIBCPP_HIDE_FROM_ABI unordered_map(size_type __n, const hasher& __hf, const allocator_type& __a)
1071      : unordered_map(__n, __hf, key_equal(), __a) {}
1072  template <class _InputIterator>
1073  _LIBCPP_HIDE_FROM_ABI
1074  unordered_map(_InputIterator __first, _InputIterator __last, size_type __n, const allocator_type& __a)
1075      : unordered_map(__first, __last, __n, hasher(), key_equal(), __a) {}
1076  template <class _InputIterator>
1077  _LIBCPP_HIDE_FROM_ABI unordered_map(
1078      _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const allocator_type& __a)
1079      : unordered_map(__first, __last, __n, __hf, key_equal(), __a) {}
1080
1081#    if _LIBCPP_STD_VER >= 23
1082  template <_ContainerCompatibleRange<value_type> _Range>
1083  _LIBCPP_HIDE_FROM_ABI unordered_map(from_range_t, _Range&& __range, size_type __n, const allocator_type& __a)
1084      : unordered_map(from_range, std::forward<_Range>(__range), __n, hasher(), key_equal(), __a) {}
1085
1086  template <_ContainerCompatibleRange<value_type> _Range>
1087  _LIBCPP_HIDE_FROM_ABI
1088  unordered_map(from_range_t, _Range&& __range, size_type __n, const hasher& __hf, const allocator_type& __a)
1089      : unordered_map(from_range, std::forward<_Range>(__range), __n, __hf, key_equal(), __a) {}
1090#    endif
1091
1092  _LIBCPP_HIDE_FROM_ABI unordered_map(initializer_list<value_type> __il, size_type __n, const allocator_type& __a)
1093      : unordered_map(__il, __n, hasher(), key_equal(), __a) {}
1094  _LIBCPP_HIDE_FROM_ABI
1095  unordered_map(initializer_list<value_type> __il, size_type __n, const hasher& __hf, const allocator_type& __a)
1096      : unordered_map(__il, __n, __hf, key_equal(), __a) {}
1097#  endif
1098  _LIBCPP_HIDE_FROM_ABI ~unordered_map() {
1099    static_assert(sizeof(std::__diagnose_unordered_container_requirements<_Key, _Hash, _Pred>(0)), "");
1100  }
1101
1102  _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(const unordered_map& __u) {
1103#  ifndef _LIBCPP_CXX03_LANG
1104    __table_ = __u.__table_;
1105#  else
1106    if (this != std::addressof(__u)) {
1107      __table_.clear();
1108      __table_.hash_function()   = __u.__table_.hash_function();
1109      __table_.key_eq()          = __u.__table_.key_eq();
1110      __table_.max_load_factor() = __u.__table_.max_load_factor();
1111      __table_.__copy_assign_alloc(__u.__table_);
1112      insert(__u.begin(), __u.end());
1113    }
1114#  endif
1115    return *this;
1116  }
1117#  ifndef _LIBCPP_CXX03_LANG
1118  _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(unordered_map&& __u)
1119      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
1120  _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(initializer_list<value_type> __il);
1121#  endif // _LIBCPP_CXX03_LANG
1122
1123  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT {
1124    return allocator_type(__table_.__node_alloc());
1125  }
1126
1127  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
1128  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
1129  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }
1130
1131  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __table_.begin(); }
1132  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __table_.end(); }
1133  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __table_.begin(); }
1134  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __table_.end(); }
1135  _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return __table_.begin(); }
1136  _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return __table_.end(); }
1137
1138  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert(const value_type& __x) { return __table_.__emplace_unique(__x); }
1139
1140  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator, const value_type& __x) { return insert(__x).first; }
1141
1142  template <class _InputIterator>
1143  _LIBCPP_HIDE_FROM_ABI void insert(_InputIterator __first, _InputIterator __last);
1144
1145#  if _LIBCPP_STD_VER >= 23
1146  template <_ContainerCompatibleRange<value_type> _Range>
1147  _LIBCPP_HIDE_FROM_ABI void insert_range(_Range&& __range) {
1148    for (auto&& __element : __range) {
1149      __table_.__emplace_unique(std::forward<decltype(__element)>(__element));
1150    }
1151  }
1152#  endif
1153
1154#  ifndef _LIBCPP_CXX03_LANG
1155  _LIBCPP_HIDE_FROM_ABI void insert(initializer_list<value_type> __il) { insert(__il.begin(), __il.end()); }
1156
1157  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert(value_type&& __x) {
1158    return __table_.__emplace_unique(std::move(__x));
1159  }
1160
1161  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator, value_type&& __x) {
1162    return __table_.__emplace_unique(std::move(__x)).first;
1163  }
1164
1165  template <class _Pp, __enable_if_t<is_constructible<value_type, _Pp>::value, int> = 0>
1166  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert(_Pp&& __x) {
1167    return __table_.__emplace_unique(std::forward<_Pp>(__x));
1168  }
1169
1170  template <class _Pp, __enable_if_t<is_constructible<value_type, _Pp>::value, int> = 0>
1171  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator, _Pp&& __x) {
1172    return insert(std::forward<_Pp>(__x)).first;
1173  }
1174
1175  template <class... _Args>
1176  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> emplace(_Args&&... __args) {
1177    return __table_.__emplace_unique(std::forward<_Args>(__args)...);
1178  }
1179
1180  template <class... _Args>
1181  _LIBCPP_HIDE_FROM_ABI iterator emplace_hint(const_iterator, _Args&&... __args) {
1182    return __table_.__emplace_unique(std::forward<_Args>(__args)...).first;
1183  }
1184
1185#  endif // _LIBCPP_CXX03_LANG
1186
1187#  if _LIBCPP_STD_VER >= 17
1188  template <class... _Args>
1189  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> try_emplace(const key_type& __k, _Args&&... __args) {
1190    return __table_.__emplace_unique_key_args(
1191        __k, piecewise_construct, std::forward_as_tuple(__k), std::forward_as_tuple(std::forward<_Args>(__args)...));
1192  }
1193
1194  template <class... _Args>
1195  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> try_emplace(key_type&& __k, _Args&&... __args) {
1196    return __table_.__emplace_unique_key_args(
1197        __k,
1198        piecewise_construct,
1199        std::forward_as_tuple(std::move(__k)),
1200        std::forward_as_tuple(std::forward<_Args>(__args)...));
1201  }
1202
1203  template <class... _Args>
1204  _LIBCPP_HIDE_FROM_ABI iterator try_emplace(const_iterator, const key_type& __k, _Args&&... __args) {
1205    return try_emplace(__k, std::forward<_Args>(__args)...).first;
1206  }
1207
1208  template <class... _Args>
1209  _LIBCPP_HIDE_FROM_ABI iterator try_emplace(const_iterator, key_type&& __k, _Args&&... __args) {
1210    return try_emplace(std::move(__k), std::forward<_Args>(__args)...).first;
1211  }
1212
1213  template <class _Vp>
1214  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert_or_assign(const key_type& __k, _Vp&& __v) {
1215    pair<iterator, bool> __res = __table_.__emplace_unique_key_args(__k, __k, std::forward<_Vp>(__v));
1216    if (!__res.second) {
1217      __res.first->second = std::forward<_Vp>(__v);
1218    }
1219    return __res;
1220  }
1221
1222  template <class _Vp>
1223  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert_or_assign(key_type&& __k, _Vp&& __v) {
1224    pair<iterator, bool> __res = __table_.__emplace_unique_key_args(__k, std::move(__k), std::forward<_Vp>(__v));
1225    if (!__res.second) {
1226      __res.first->second = std::forward<_Vp>(__v);
1227    }
1228    return __res;
1229  }
1230
1231  template <class _Vp>
1232  _LIBCPP_HIDE_FROM_ABI iterator insert_or_assign(const_iterator, const key_type& __k, _Vp&& __v) {
1233    return insert_or_assign(__k, std::forward<_Vp>(__v)).first;
1234  }
1235
1236  template <class _Vp>
1237  _LIBCPP_HIDE_FROM_ABI iterator insert_or_assign(const_iterator, key_type&& __k, _Vp&& __v) {
1238    return insert_or_assign(std::move(__k), std::forward<_Vp>(__v)).first;
1239  }
1240#  endif // _LIBCPP_STD_VER >= 17
1241
1242  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p) { return __table_.erase(__p.__i_); }
1243  _LIBCPP_HIDE_FROM_ABI iterator erase(iterator __p) { return __table_.erase(__p.__i_); }
1244  _LIBCPP_HIDE_FROM_ABI size_type erase(const key_type& __k) { return __table_.__erase_unique(__k); }
1245  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __first, const_iterator __last) {
1246    return __table_.erase(__first.__i_, __last.__i_);
1247  }
1248  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { __table_.clear(); }
1249
1250#  if _LIBCPP_STD_VER >= 17
1251  _LIBCPP_HIDE_FROM_ABI insert_return_type insert(node_type&& __nh) {
1252    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
1253                                        "node_type with incompatible allocator passed to unordered_map::insert()");
1254    return __table_.template __node_handle_insert_unique< node_type, insert_return_type>(std::move(__nh));
1255  }
1256  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __hint, node_type&& __nh) {
1257    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
1258                                        "node_type with incompatible allocator passed to unordered_map::insert()");
1259    return __table_.template __node_handle_insert_unique<node_type>(__hint.__i_, std::move(__nh));
1260  }
1261  _LIBCPP_HIDE_FROM_ABI node_type extract(key_type const& __key) {
1262    return __table_.template __node_handle_extract<node_type>(__key);
1263  }
1264  _LIBCPP_HIDE_FROM_ABI node_type extract(const_iterator __it) {
1265    return __table_.template __node_handle_extract<node_type>(__it.__i_);
1266  }
1267
1268  template <class _H2, class _P2>
1269  _LIBCPP_HIDE_FROM_ABI void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>& __source) {
1270    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
1271        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
1272    return __table_.__node_handle_merge_unique(__source.__table_);
1273  }
1274  template <class _H2, class _P2>
1275  _LIBCPP_HIDE_FROM_ABI void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>&& __source) {
1276    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
1277        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
1278    return __table_.__node_handle_merge_unique(__source.__table_);
1279  }
1280  template <class _H2, class _P2>
1281  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>& __source) {
1282    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
1283        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
1284    return __table_.__node_handle_merge_unique(__source.__table_);
1285  }
1286  template <class _H2, class _P2>
1287  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>&& __source) {
1288    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
1289        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
1290    return __table_.__node_handle_merge_unique(__source.__table_);
1291  }
1292#  endif
1293
1294  _LIBCPP_HIDE_FROM_ABI void swap(unordered_map& __u) _NOEXCEPT_(__is_nothrow_swappable_v<__table>) {
1295    __table_.swap(__u.__table_);
1296  }
1297
1298  _LIBCPP_HIDE_FROM_ABI hasher hash_function() const { return __table_.hash_function().hash_function(); }
1299  _LIBCPP_HIDE_FROM_ABI key_equal key_eq() const { return __table_.key_eq().key_eq(); }
1300
1301  _LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __table_.find(__k); }
1302  _LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __table_.find(__k); }
1303#  if _LIBCPP_STD_VER >= 20
1304  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1305  _LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
1306    return __table_.find(__k);
1307  }
1308  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1309  _LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
1310    return __table_.find(__k);
1311  }
1312#  endif // _LIBCPP_STD_VER >= 20
1313
1314  _LIBCPP_HIDE_FROM_ABI size_type count(const key_type& __k) const { return __table_.__count_unique(__k); }
1315#  if _LIBCPP_STD_VER >= 20
1316  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1317  _LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
1318    return __table_.__count_unique(__k);
1319  }
1320#  endif // _LIBCPP_STD_VER >= 20
1321
1322#  if _LIBCPP_STD_VER >= 20
1323  _LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }
1324
1325  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1326  _LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
1327    return find(__k) != end();
1328  }
1329#  endif // _LIBCPP_STD_VER >= 20
1330
1331  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const key_type& __k) {
1332    return __table_.__equal_range_unique(__k);
1333  }
1334  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const key_type& __k) const {
1335    return __table_.__equal_range_unique(__k);
1336  }
1337#  if _LIBCPP_STD_VER >= 20
1338  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1339  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
1340    return __table_.__equal_range_unique(__k);
1341  }
1342  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
1343  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
1344    return __table_.__equal_range_unique(__k);
1345  }
1346#  endif // _LIBCPP_STD_VER >= 20
1347
1348  _LIBCPP_HIDE_FROM_ABI mapped_type& operator[](const key_type& __k);
1349#  ifndef _LIBCPP_CXX03_LANG
1350  _LIBCPP_HIDE_FROM_ABI mapped_type& operator[](key_type&& __k);
1351#  endif
1352
1353  _LIBCPP_HIDE_FROM_ABI mapped_type& at(const key_type& __k);
1354  _LIBCPP_HIDE_FROM_ABI const mapped_type& at(const key_type& __k) const;
1355
1356  _LIBCPP_HIDE_FROM_ABI size_type bucket_count() const _NOEXCEPT { return __table_.bucket_count(); }
1357  _LIBCPP_HIDE_FROM_ABI size_type max_bucket_count() const _NOEXCEPT { return __table_.max_bucket_count(); }
1358
1359  _LIBCPP_HIDE_FROM_ABI size_type bucket_size(size_type __n) const { return __table_.bucket_size(__n); }
1360  _LIBCPP_HIDE_FROM_ABI size_type bucket(const key_type& __k) const { return __table_.bucket(__k); }
1361
1362  _LIBCPP_HIDE_FROM_ABI local_iterator begin(size_type __n) { return __table_.begin(__n); }
1363  _LIBCPP_HIDE_FROM_ABI local_iterator end(size_type __n) { return __table_.end(__n); }
1364  _LIBCPP_HIDE_FROM_ABI const_local_iterator begin(size_type __n) const { return __table_.cbegin(__n); }
1365  _LIBCPP_HIDE_FROM_ABI const_local_iterator end(size_type __n) const { return __table_.cend(__n); }
1366  _LIBCPP_HIDE_FROM_ABI const_local_iterator cbegin(size_type __n) const { return __table_.cbegin(__n); }
1367  _LIBCPP_HIDE_FROM_ABI const_local_iterator cend(size_type __n) const { return __table_.cend(__n); }
1368
1369  _LIBCPP_HIDE_FROM_ABI float load_factor() const _NOEXCEPT { return __table_.load_factor(); }
1370  _LIBCPP_HIDE_FROM_ABI float max_load_factor() const _NOEXCEPT { return __table_.max_load_factor(); }
1371  _LIBCPP_HIDE_FROM_ABI void max_load_factor(float __mlf) { __table_.max_load_factor(__mlf); }
1372  _LIBCPP_HIDE_FROM_ABI void rehash(size_type __n) { __table_.__rehash_unique(__n); }
1373  _LIBCPP_HIDE_FROM_ABI void reserve(size_type __n) { __table_.__reserve_unique(__n); }
1374
1375private:
1376#  ifdef _LIBCPP_CXX03_LANG
1377  _LIBCPP_HIDE_FROM_ABI __node_holder __construct_node_with_key(const key_type& __k);
1378#  endif
1379};
1380
1381#  if _LIBCPP_STD_VER >= 17
1382template <class _InputIterator,
1383          class _Hash      = hash<__iter_key_type<_InputIterator>>,
1384          class _Pred      = equal_to<__iter_key_type<_InputIterator>>,
1385          class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
1386          class            = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
1387          class            = enable_if_t<!__is_allocator<_Hash>::value>,
1388          class            = enable_if_t<!is_integral<_Hash>::value>,
1389          class            = enable_if_t<!__is_allocator<_Pred>::value>,
1390          class            = enable_if_t<__is_allocator<_Allocator>::value>>
1391unordered_map(_InputIterator,
1392              _InputIterator,
1393              typename allocator_traits<_Allocator>::size_type = 0,
1394              _Hash                                            = _Hash(),
1395              _Pred                                            = _Pred(),
1396              _Allocator                                       = _Allocator())
1397    -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Hash, _Pred, _Allocator>;
1398
1399#    if _LIBCPP_STD_VER >= 23
1400template <ranges::input_range _Range,
1401          class _Hash      = hash<__range_key_type<_Range>>,
1402          class _Pred      = equal_to<__range_key_type<_Range>>,
1403          class _Allocator = allocator<__range_to_alloc_type<_Range>>,
1404          class            = enable_if_t<!__is_allocator<_Hash>::value>,
1405          class            = enable_if_t<!is_integral<_Hash>::value>,
1406          class            = enable_if_t<!__is_allocator<_Pred>::value>,
1407          class            = enable_if_t<__is_allocator<_Allocator>::value>>
1408unordered_map(from_range_t,
1409              _Range&&,
1410              typename allocator_traits<_Allocator>::size_type = 0,
1411              _Hash                                            = _Hash(),
1412              _Pred                                            = _Pred(),
1413              _Allocator                                       = _Allocator())
1414    -> unordered_map<__range_key_type<_Range>, __range_mapped_type<_Range>, _Hash, _Pred, _Allocator>; // C++23
1415#    endif
1416
1417template <class _Key,
1418          class _Tp,
1419          class _Hash      = hash<remove_const_t<_Key>>,
1420          class _Pred      = equal_to<remove_const_t<_Key>>,
1421          class _Allocator = allocator<pair<const _Key, _Tp>>,
1422          class            = enable_if_t<!__is_allocator<_Hash>::value>,
1423          class            = enable_if_t<!is_integral<_Hash>::value>,
1424          class            = enable_if_t<!__is_allocator<_Pred>::value>,
1425          class            = enable_if_t<__is_allocator<_Allocator>::value>>
1426unordered_map(initializer_list<pair<_Key, _Tp>>,
1427              typename allocator_traits<_Allocator>::size_type = 0,
1428              _Hash                                            = _Hash(),
1429              _Pred                                            = _Pred(),
1430              _Allocator = _Allocator()) -> unordered_map<remove_const_t<_Key>, _Tp, _Hash, _Pred, _Allocator>;
1431
1432template <class _InputIterator,
1433          class _Allocator,
1434          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
1435          class = enable_if_t<__is_allocator<_Allocator>::value>>
1436unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
1437    -> unordered_map<__iter_key_type<_InputIterator>,
1438                     __iter_mapped_type<_InputIterator>,
1439                     hash<__iter_key_type<_InputIterator>>,
1440                     equal_to<__iter_key_type<_InputIterator>>,
1441                     _Allocator>;
1442
1443template <class _InputIterator,
1444          class _Allocator,
1445          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
1446          class = enable_if_t<__is_allocator<_Allocator>::value>>
1447unordered_map(_InputIterator, _InputIterator, _Allocator)
1448    -> unordered_map<__iter_key_type<_InputIterator>,
1449                     __iter_mapped_type<_InputIterator>,
1450                     hash<__iter_key_type<_InputIterator>>,
1451                     equal_to<__iter_key_type<_InputIterator>>,
1452                     _Allocator>;
1453
1454template <class _InputIterator,
1455          class _Hash,
1456          class _Allocator,
1457          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
1458          class = enable_if_t<!__is_allocator<_Hash>::value>,
1459          class = enable_if_t<!is_integral<_Hash>::value>,
1460          class = enable_if_t<__is_allocator<_Allocator>::value>>
1461unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
1462    -> unordered_map<__iter_key_type<_InputIterator>,
1463                     __iter_mapped_type<_InputIterator>,
1464                     _Hash,
1465                     equal_to<__iter_key_type<_InputIterator>>,
1466                     _Allocator>;
1467
1468#    if _LIBCPP_STD_VER >= 23
1469
1470template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
1471unordered_map(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Allocator)
1472    -> unordered_map<__range_key_type<_Range>,
1473                     __range_mapped_type<_Range>,
1474                     hash<__range_key_type<_Range>>,
1475                     equal_to<__range_key_type<_Range>>,
1476                     _Allocator>;
1477
1478template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
1479unordered_map(from_range_t, _Range&&, _Allocator)
1480    -> unordered_map<__range_key_type<_Range>,
1481                     __range_mapped_type<_Range>,
1482                     hash<__range_key_type<_Range>>,
1483                     equal_to<__range_key_type<_Range>>,
1484                     _Allocator>;
1485
1486template <ranges::input_range _Range,
1487          class _Hash,
1488          class _Allocator,
1489          class = enable_if_t<!__is_allocator<_Hash>::value>,
1490          class = enable_if_t<!is_integral<_Hash>::value>,
1491          class = enable_if_t<__is_allocator<_Allocator>::value>>
1492unordered_map(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
1493    -> unordered_map<__range_key_type<_Range>,
1494                     __range_mapped_type<_Range>,
1495                     _Hash,
1496                     equal_to<__range_key_type<_Range>>,
1497                     _Allocator>;
1498
1499#    endif
1500
1501template <class _Key, class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
1502unordered_map(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Allocator)
1503    -> unordered_map<remove_const_t<_Key>, _Tp, hash<remove_const_t<_Key>>, equal_to<remove_const_t<_Key>>, _Allocator>;
1504
1505template <class _Key, class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
1506unordered_map(initializer_list<pair<_Key, _Tp>>, _Allocator)
1507    -> unordered_map<remove_const_t<_Key>, _Tp, hash<remove_const_t<_Key>>, equal_to<remove_const_t<_Key>>, _Allocator>;
1508
1509template <class _Key,
1510          class _Tp,
1511          class _Hash,
1512          class _Allocator,
1513          class = enable_if_t<!__is_allocator<_Hash>::value>,
1514          class = enable_if_t<!is_integral<_Hash>::value>,
1515          class = enable_if_t<__is_allocator<_Allocator>::value>>
1516unordered_map(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
1517    -> unordered_map<remove_const_t<_Key>, _Tp, _Hash, equal_to<remove_const_t<_Key>>, _Allocator>;
1518#  endif
1519
1520template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1521unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(size_type __n, const hasher& __hf, const key_equal& __eql)
1522    : __table_(__hf, __eql) {
1523  __table_.__rehash_unique(__n);
1524}
1525
1526template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1527unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
1528    size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
1529    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
1530  __table_.__rehash_unique(__n);
1531}
1532
1533template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1534inline unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(const allocator_type& __a)
1535    : __table_(typename __table::allocator_type(__a)) {}
1536
1537template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1538template <class _InputIterator>
1539unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(_InputIterator __first, _InputIterator __last) {
1540  insert(__first, __last);
1541}
1542
1543template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1544template <class _InputIterator>
1545unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
1546    _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const key_equal& __eql)
1547    : __table_(__hf, __eql) {
1548  __table_.__rehash_unique(__n);
1549  insert(__first, __last);
1550}
1551
1552template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1553template <class _InputIterator>
1554unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
1555    _InputIterator __first,
1556    _InputIterator __last,
1557    size_type __n,
1558    const hasher& __hf,
1559    const key_equal& __eql,
1560    const allocator_type& __a)
1561    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
1562  __table_.__rehash_unique(__n);
1563  insert(__first, __last);
1564}
1565
1566template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1567unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(const unordered_map& __u) : __table_(__u.__table_) {
1568  __table_.__rehash_unique(__u.bucket_count());
1569  insert(__u.begin(), __u.end());
1570}
1571
1572template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1573unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(const unordered_map& __u, const allocator_type& __a)
1574    : __table_(__u.__table_, typename __table::allocator_type(__a)) {
1575  __table_.__rehash_unique(__u.bucket_count());
1576  insert(__u.begin(), __u.end());
1577}
1578
1579#  ifndef _LIBCPP_CXX03_LANG
1580
1581template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1582inline unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(unordered_map&& __u)
1583    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
1584    : __table_(std::move(__u.__table_)) {}
1585
1586template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1587unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(unordered_map&& __u, const allocator_type& __a)
1588    : __table_(std::move(__u.__table_), typename __table::allocator_type(__a)) {
1589  if (__a != __u.get_allocator()) {
1590    iterator __i = __u.begin();
1591    while (__u.size() != 0)
1592      __table_.__insert_unique_from_orphaned_node(std::move(__u.__table_.remove((__i++).__i_)->__get_value()));
1593  }
1594}
1595
1596template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1597unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(initializer_list<value_type> __il) {
1598  insert(__il.begin(), __il.end());
1599}
1600
1601template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1602unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
1603    initializer_list<value_type> __il, size_type __n, const hasher& __hf, const key_equal& __eql)
1604    : __table_(__hf, __eql) {
1605  __table_.__rehash_unique(__n);
1606  insert(__il.begin(), __il.end());
1607}
1608
1609template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1610unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
1611    initializer_list<value_type> __il,
1612    size_type __n,
1613    const hasher& __hf,
1614    const key_equal& __eql,
1615    const allocator_type& __a)
1616    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
1617  __table_.__rehash_unique(__n);
1618  insert(__il.begin(), __il.end());
1619}
1620
1621template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1622inline unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>&
1623unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(unordered_map&& __u)
1624    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) {
1625  __table_ = std::move(__u.__table_);
1626  return *this;
1627}
1628
1629template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1630inline unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>&
1631unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(initializer_list<value_type> __il) {
1632  __table_.__assign_unique(__il.begin(), __il.end());
1633  return *this;
1634}
1635
1636#  endif // _LIBCPP_CXX03_LANG
1637
1638template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1639template <class _InputIterator>
1640inline void unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::insert(_InputIterator __first, _InputIterator __last) {
1641  for (; __first != __last; ++__first)
1642    __table_.__emplace_unique(*__first);
1643}
1644
1645#  ifndef _LIBCPP_CXX03_LANG
1646
1647template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1648_Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](const key_type& __k) {
1649  return __table_
1650      .__emplace_unique_key_args(__k, piecewise_construct, std::forward_as_tuple(__k), std::forward_as_tuple())
1651      .first->second;
1652}
1653
1654template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1655_Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](key_type&& __k) {
1656  return __table_
1657      .__emplace_unique_key_args(
1658          __k, piecewise_construct, std::forward_as_tuple(std::move(__k)), std::forward_as_tuple())
1659      .first->second;
1660}
1661#  else // _LIBCPP_CXX03_LANG
1662
1663template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1664typename unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::__node_holder
1665unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::__construct_node_with_key(const key_type& __k) {
1666  __node_allocator& __na = __table_.__node_alloc();
1667  __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
1668  __node_traits::construct(__na, std::addressof(__h->__get_value().first), __k);
1669  __h.get_deleter().__first_constructed = true;
1670  __node_traits::construct(__na, std::addressof(__h->__get_value().second));
1671  __h.get_deleter().__second_constructed = true;
1672  return __h;
1673}
1674
1675template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1676_Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](const key_type& __k) {
1677  iterator __i = find(__k);
1678  if (__i != end())
1679    return __i->second;
1680  __node_holder __h        = __construct_node_with_key(__k);
1681  pair<iterator, bool> __r = __table_.__node_insert_unique(__h.get());
1682  __h.release();
1683  return __r.first->second;
1684}
1685
1686#  endif // _LIBCPP_CXX03_LANG
1687
1688template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1689_Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::at(const key_type& __k) {
1690  iterator __i = find(__k);
1691  if (__i == end())
1692    std::__throw_out_of_range("unordered_map::at: key not found");
1693  return __i->second;
1694}
1695
1696template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1697const _Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::at(const key_type& __k) const {
1698  const_iterator __i = find(__k);
1699  if (__i == end())
1700    std::__throw_out_of_range("unordered_map::at: key not found");
1701  return __i->second;
1702}
1703
1704template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1705inline _LIBCPP_HIDE_FROM_ABI void
1706swap(unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x, unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
1707    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
1708  __x.swap(__y);
1709}
1710
1711#  if _LIBCPP_STD_VER >= 20
1712template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc, class _Predicate>
1713inline _LIBCPP_HIDE_FROM_ABI typename unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::size_type
1714erase_if(unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __c, _Predicate __pred) {
1715  return std::__libcpp_erase_if_container(__c, __pred);
1716}
1717#  endif
1718
1719template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1720_LIBCPP_HIDE_FROM_ABI bool operator==(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
1721                                      const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y) {
1722  if (__x.size() != __y.size())
1723    return false;
1724  typedef typename unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::const_iterator const_iterator;
1725  for (const_iterator __i = __x.begin(), __ex = __x.end(), __ey = __y.end(); __i != __ex; ++__i) {
1726    const_iterator __j = __y.find(__i->first);
1727    if (__j == __ey || !(*__i == *__j))
1728      return false;
1729  }
1730  return true;
1731}
1732
1733#  if _LIBCPP_STD_VER <= 17
1734
1735template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1736inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
1737                                             const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y) {
1738  return !(__x == __y);
1739}
1740
1741#  endif
1742
1743template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
1744struct __container_traits<unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc> > {
1745  // http://eel.is/c++draft/unord.req.except#2
1746  //  For unordered associative containers, if an exception is thrown by any operation
1747  //  other than the container's hash function from within an insert or emplace function
1748  //  inserting a single element, the insertion has no effect.
1749  static _LIBCPP_CONSTEXPR const bool __emplacement_has_strong_exception_safety_guarantee =
1750      __is_nothrow_invocable_v<_Hash, const _Key&>;
1751
1752  static _LIBCPP_CONSTEXPR const bool __reservable = true;
1753};
1754
1755template <class _Key,
1756          class _Tp,
1757          class _Hash  = hash<_Key>,
1758          class _Pred  = equal_to<_Key>,
1759          class _Alloc = allocator<pair<const _Key, _Tp> > >
1760class unordered_multimap {
1761public:
1762  // types
1763  typedef _Key key_type;
1764  typedef _Tp mapped_type;
1765  typedef __type_identity_t<_Hash> hasher;
1766  typedef __type_identity_t<_Pred> key_equal;
1767  typedef __type_identity_t<_Alloc> allocator_type;
1768  typedef pair<const key_type, mapped_type> value_type;
1769  typedef value_type& reference;
1770  typedef const value_type& const_reference;
1771  static_assert(__check_valid_allocator<allocator_type>::value, "");
1772  static_assert(is_same<value_type, typename allocator_type::value_type>::value,
1773                "Allocator::value_type must be same type as value_type");
1774
1775private:
1776  typedef __hash_value_type<key_type, mapped_type> __value_type;
1777  typedef __unordered_map_hasher<key_type, value_type, hasher, key_equal> __hasher;
1778  typedef __unordered_map_equal<key_type, value_type, key_equal, hasher> __key_equal;
1779
1780  typedef __hash_table<__value_type, __hasher, __key_equal, allocator_type> __table;
1781
1782  __table __table_;
1783
1784  typedef typename __table::_NodeTypes _NodeTypes;
1785  typedef typename __table::__node_traits __node_traits;
1786  typedef typename __table::__node_allocator __node_allocator;
1787  typedef typename __table::__node __node;
1788  typedef __hash_map_node_destructor<__node_allocator> _Dp;
1789  typedef unique_ptr<__node, _Dp> __node_holder;
1790  typedef allocator_traits<allocator_type> __alloc_traits;
1791  static_assert(is_same<typename __node_traits::size_type, typename __alloc_traits::size_type>::value,
1792                "Allocator uses different size_type for different types");
1793
1794public:
1795  typedef typename __alloc_traits::pointer pointer;
1796  typedef typename __alloc_traits::const_pointer const_pointer;
1797  typedef typename __table::size_type size_type;
1798  typedef typename __table::difference_type difference_type;
1799
1800  typedef __hash_map_iterator<typename __table::iterator> iterator;
1801  typedef __hash_map_const_iterator<typename __table::const_iterator> const_iterator;
1802  typedef __hash_map_iterator<typename __table::local_iterator> local_iterator;
1803  typedef __hash_map_const_iterator<typename __table::const_local_iterator> const_local_iterator;
1804
1805#  if _LIBCPP_STD_VER >= 17
1806  typedef __map_node_handle<__node, allocator_type> node_type;
1807#  endif
1808
1809  template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
1810  friend class unordered_map;
1811  template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
1812  friend class unordered_multimap;
1813
1814  _LIBCPP_HIDE_FROM_ABI unordered_multimap() _NOEXCEPT_(is_nothrow_default_constructible<__table>::value) {}
1815  explicit _LIBCPP_HIDE_FROM_ABI
1816  unordered_multimap(size_type __n, const hasher& __hf = hasher(), const key_equal& __eql = key_equal());
1817  _LIBCPP_HIDE_FROM_ABI
1818  unordered_multimap(size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a);
1819  template <class _InputIterator>
1820  _LIBCPP_HIDE_FROM_ABI unordered_multimap(_InputIterator __first, _InputIterator __last);
1821  template <class _InputIterator>
1822  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
1823      _InputIterator __first,
1824      _InputIterator __last,
1825      size_type __n,
1826      const hasher& __hf     = hasher(),
1827      const key_equal& __eql = key_equal());
1828  template <class _InputIterator>
1829  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
1830      _InputIterator __first,
1831      _InputIterator __last,
1832      size_type __n,
1833      const hasher& __hf,
1834      const key_equal& __eql,
1835      const allocator_type& __a);
1836
1837#  if _LIBCPP_STD_VER >= 23
1838  template <_ContainerCompatibleRange<value_type> _Range>
1839  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
1840      from_range_t,
1841      _Range&& __range,
1842      size_type __n             = /*implementation-defined*/ 0,
1843      const hasher& __hf        = hasher(),
1844      const key_equal& __eql    = key_equal(),
1845      const allocator_type& __a = allocator_type())
1846      : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
1847    if (__n > 0) {
1848      __table_.__rehash_multi(__n);
1849    }
1850    insert_range(std::forward<_Range>(__range));
1851  }
1852#  endif
1853
1854  _LIBCPP_HIDE_FROM_ABI explicit unordered_multimap(const allocator_type& __a);
1855  _LIBCPP_HIDE_FROM_ABI unordered_multimap(const unordered_multimap& __u);
1856  _LIBCPP_HIDE_FROM_ABI unordered_multimap(const unordered_multimap& __u, const allocator_type& __a);
1857#  ifndef _LIBCPP_CXX03_LANG
1858  _LIBCPP_HIDE_FROM_ABI unordered_multimap(unordered_multimap&& __u)
1859      _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
1860  _LIBCPP_HIDE_FROM_ABI unordered_multimap(unordered_multimap&& __u, const allocator_type& __a);
1861  _LIBCPP_HIDE_FROM_ABI unordered_multimap(initializer_list<value_type> __il);
1862  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
1863      initializer_list<value_type> __il,
1864      size_type __n,
1865      const hasher& __hf     = hasher(),
1866      const key_equal& __eql = key_equal());
1867  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
1868      initializer_list<value_type> __il,
1869      size_type __n,
1870      const hasher& __hf,
1871      const key_equal& __eql,
1872      const allocator_type& __a);
1873#  endif // _LIBCPP_CXX03_LANG
1874#  if _LIBCPP_STD_VER >= 14
1875  _LIBCPP_HIDE_FROM_ABI unordered_multimap(size_type __n, const allocator_type& __a)
1876      : unordered_multimap(__n, hasher(), key_equal(), __a) {}
1877  _LIBCPP_HIDE_FROM_ABI unordered_multimap(size_type __n, const hasher& __hf, const allocator_type& __a)
1878      : unordered_multimap(__n, __hf, key_equal(), __a) {}
1879  template <class _InputIterator>
1880  _LIBCPP_HIDE_FROM_ABI
1881  unordered_multimap(_InputIterator __first, _InputIterator __last, size_type __n, const allocator_type& __a)
1882      : unordered_multimap(__first, __last, __n, hasher(), key_equal(), __a) {}
1883  template <class _InputIterator>
1884  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
1885      _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const allocator_type& __a)
1886      : unordered_multimap(__first, __last, __n, __hf, key_equal(), __a) {}
1887
1888#    if _LIBCPP_STD_VER >= 23
1889  template <_ContainerCompatibleRange<value_type> _Range>
1890  _LIBCPP_HIDE_FROM_ABI unordered_multimap(from_range_t, _Range&& __range, size_type __n, const allocator_type& __a)
1891      : unordered_multimap(from_range, std::forward<_Range>(__range), __n, hasher(), key_equal(), __a) {}
1892
1893  template <_ContainerCompatibleRange<value_type> _Range>
1894  _LIBCPP_HIDE_FROM_ABI
1895  unordered_multimap(from_range_t, _Range&& __range, size_type __n, const hasher& __hf, const allocator_type& __a)
1896      : unordered_multimap(from_range, std::forward<_Range>(__range), __n, __hf, key_equal(), __a) {}
1897#    endif
1898
1899  _LIBCPP_HIDE_FROM_ABI unordered_multimap(initializer_list<value_type> __il, size_type __n, const allocator_type& __a)
1900      : unordered_multimap(__il, __n, hasher(), key_equal(), __a) {}
1901  _LIBCPP_HIDE_FROM_ABI
1902  unordered_multimap(initializer_list<value_type> __il, size_type __n, const hasher& __hf, const allocator_type& __a)
1903      : unordered_multimap(__il, __n, __hf, key_equal(), __a) {}
1904#  endif
1905  _LIBCPP_HIDE_FROM_ABI ~unordered_multimap() {
1906    static_assert(sizeof(std::__diagnose_unordered_container_requirements<_Key, _Hash, _Pred>(0)), "");
1907  }
1908
1909  _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(const unordered_multimap& __u) {
1910#  ifndef _LIBCPP_CXX03_LANG
1911    __table_ = __u.__table_;
1912#  else
1913    if (this != std::addressof(__u)) {
1914      __table_.clear();
1915      __table_.hash_function()   = __u.__table_.hash_function();
1916      __table_.key_eq()          = __u.__table_.key_eq();
1917      __table_.max_load_factor() = __u.__table_.max_load_factor();
1918      __table_.__copy_assign_alloc(__u.__table_);
1919      insert(__u.begin(), __u.end());
1920    }
1921#  endif
1922    return *this;
1923  }
1924#  ifndef _LIBCPP_CXX03_LANG
1925  _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(unordered_multimap&& __u)
1926      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
1927  _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(initializer_list<value_type> __il);
1928#  endif // _LIBCPP_CXX03_LANG
1929
1930  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT {
1931    return allocator_type(__table_.__node_alloc());
1932  }
1933
1934  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
1935  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
1936  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }
1937
1938  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __table_.begin(); }
1939  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __table_.end(); }
1940  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __table_.begin(); }
1941  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __table_.end(); }
1942  _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return __table_.begin(); }
1943  _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return __table_.end(); }
1944
1945  _LIBCPP_HIDE_FROM_ABI iterator insert(const value_type& __x) { return __table_.__emplace_multi(__x); }
1946
1947  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __x) {
1948    return __table_.__emplace_hint_multi(__p.__i_, __x);
1949  }
1950
1951  template <class _InputIterator>
1952  _LIBCPP_HIDE_FROM_ABI void insert(_InputIterator __first, _InputIterator __last);
1953
1954#  if _LIBCPP_STD_VER >= 23
1955  template <_ContainerCompatibleRange<value_type> _Range>
1956  _LIBCPP_HIDE_FROM_ABI void insert_range(_Range&& __range) {
1957    for (auto&& __element : __range) {
1958      __table_.__emplace_multi(std::forward<decltype(__element)>(__element));
1959    }
1960  }
1961#  endif
1962
1963#  ifndef _LIBCPP_CXX03_LANG
1964  _LIBCPP_HIDE_FROM_ABI void insert(initializer_list<value_type> __il) { insert(__il.begin(), __il.end()); }
1965  _LIBCPP_HIDE_FROM_ABI iterator insert(value_type&& __x) { return __table_.__emplace_multi(std::move(__x)); }
1966
1967  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, value_type&& __x) {
1968    return __table_.__emplace_hint_multi(__p.__i_, std::move(__x));
1969  }
1970
1971  template <class _Pp, __enable_if_t<is_constructible<value_type, _Pp>::value, int> = 0>
1972  _LIBCPP_HIDE_FROM_ABI iterator insert(_Pp&& __x) {
1973    return __table_.__emplace_multi(std::forward<_Pp>(__x));
1974  }
1975
1976  template <class _Pp, __enable_if_t<is_constructible<value_type, _Pp>::value, int> = 0>
1977  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _Pp&& __x) {
1978    return __table_.__emplace_hint_multi(__p.__i_, std::forward<_Pp>(__x));
1979  }
1980
1981  template <class... _Args>
1982  _LIBCPP_HIDE_FROM_ABI iterator emplace(_Args&&... __args) {
1983    return __table_.__emplace_multi(std::forward<_Args>(__args)...);
1984  }
1985
1986  template <class... _Args>
1987  _LIBCPP_HIDE_FROM_ABI iterator emplace_hint(const_iterator __p, _Args&&... __args) {
1988    return __table_.__emplace_hint_multi(__p.__i_, std::forward<_Args>(__args)...);
1989  }
1990#  endif // _LIBCPP_CXX03_LANG
1991
1992  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p) { return __table_.erase(__p.__i_); }
1993  _LIBCPP_HIDE_FROM_ABI iterator erase(iterator __p) { return __table_.erase(__p.__i_); }
1994  _LIBCPP_HIDE_FROM_ABI size_type erase(const key_type& __k) { return __table_.__erase_multi(__k); }
1995  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __first, const_iterator __last) {
1996    return __table_.erase(__first.__i_, __last.__i_);
1997  }
1998  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { __table_.clear(); }
1999
2000#  if _LIBCPP_STD_VER >= 17
2001  _LIBCPP_HIDE_FROM_ABI iterator insert(node_type&& __nh) {
2002    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
2003                                        "node_type with incompatible allocator passed to unordered_multimap::insert()");
2004    return __table_.template __node_handle_insert_multi<node_type>(std::move(__nh));
2005  }
2006  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __hint, node_type&& __nh) {
2007    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
2008                                        "node_type with incompatible allocator passed to unordered_multimap::insert()");
2009    return __table_.template __node_handle_insert_multi<node_type>(__hint.__i_, std::move(__nh));
2010  }
2011  _LIBCPP_HIDE_FROM_ABI node_type extract(key_type const& __key) {
2012    return __table_.template __node_handle_extract<node_type>(__key);
2013  }
2014  _LIBCPP_HIDE_FROM_ABI node_type extract(const_iterator __it) {
2015    return __table_.template __node_handle_extract<node_type>(__it.__i_);
2016  }
2017
2018  template <class _H2, class _P2>
2019  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>& __source) {
2020    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
2021        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
2022    return __table_.__node_handle_merge_multi(__source.__table_);
2023  }
2024  template <class _H2, class _P2>
2025  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>&& __source) {
2026    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
2027        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
2028    return __table_.__node_handle_merge_multi(__source.__table_);
2029  }
2030  template <class _H2, class _P2>
2031  _LIBCPP_HIDE_FROM_ABI void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>& __source) {
2032    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
2033        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
2034    return __table_.__node_handle_merge_multi(__source.__table_);
2035  }
2036  template <class _H2, class _P2>
2037  _LIBCPP_HIDE_FROM_ABI void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>&& __source) {
2038    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
2039        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
2040    return __table_.__node_handle_merge_multi(__source.__table_);
2041  }
2042#  endif
2043
2044  _LIBCPP_HIDE_FROM_ABI void swap(unordered_multimap& __u) _NOEXCEPT_(__is_nothrow_swappable_v<__table>) {
2045    __table_.swap(__u.__table_);
2046  }
2047
2048  _LIBCPP_HIDE_FROM_ABI hasher hash_function() const { return __table_.hash_function().hash_function(); }
2049  _LIBCPP_HIDE_FROM_ABI key_equal key_eq() const { return __table_.key_eq().key_eq(); }
2050
2051  _LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __table_.find(__k); }
2052  _LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __table_.find(__k); }
2053#  if _LIBCPP_STD_VER >= 20
2054  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
2055  _LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
2056    return __table_.find(__k);
2057  }
2058  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
2059  _LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
2060    return __table_.find(__k);
2061  }
2062#  endif // _LIBCPP_STD_VER >= 20
2063
2064  _LIBCPP_HIDE_FROM_ABI size_type count(const key_type& __k) const { return __table_.__count_multi(__k); }
2065#  if _LIBCPP_STD_VER >= 20
2066  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
2067  _LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
2068    return __table_.__count_multi(__k);
2069  }
2070#  endif // _LIBCPP_STD_VER >= 20
2071
2072#  if _LIBCPP_STD_VER >= 20
2073  _LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }
2074
2075  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
2076  _LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
2077    return find(__k) != end();
2078  }
2079#  endif // _LIBCPP_STD_VER >= 20
2080
2081  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const key_type& __k) {
2082    return __table_.__equal_range_multi(__k);
2083  }
2084  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const key_type& __k) const {
2085    return __table_.__equal_range_multi(__k);
2086  }
2087#  if _LIBCPP_STD_VER >= 20
2088  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
2089  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
2090    return __table_.__equal_range_multi(__k);
2091  }
2092  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
2093  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
2094    return __table_.__equal_range_multi(__k);
2095  }
2096#  endif // _LIBCPP_STD_VER >= 20
2097
2098  _LIBCPP_HIDE_FROM_ABI size_type bucket_count() const _NOEXCEPT { return __table_.bucket_count(); }
2099  _LIBCPP_HIDE_FROM_ABI size_type max_bucket_count() const _NOEXCEPT { return __table_.max_bucket_count(); }
2100
2101  _LIBCPP_HIDE_FROM_ABI size_type bucket_size(size_type __n) const { return __table_.bucket_size(__n); }
2102  _LIBCPP_HIDE_FROM_ABI size_type bucket(const key_type& __k) const { return __table_.bucket(__k); }
2103
2104  _LIBCPP_HIDE_FROM_ABI local_iterator begin(size_type __n) { return __table_.begin(__n); }
2105  _LIBCPP_HIDE_FROM_ABI local_iterator end(size_type __n) { return __table_.end(__n); }
2106  _LIBCPP_HIDE_FROM_ABI const_local_iterator begin(size_type __n) const { return __table_.cbegin(__n); }
2107  _LIBCPP_HIDE_FROM_ABI const_local_iterator end(size_type __n) const { return __table_.cend(__n); }
2108  _LIBCPP_HIDE_FROM_ABI const_local_iterator cbegin(size_type __n) const { return __table_.cbegin(__n); }
2109  _LIBCPP_HIDE_FROM_ABI const_local_iterator cend(size_type __n) const { return __table_.cend(__n); }
2110
2111  _LIBCPP_HIDE_FROM_ABI float load_factor() const _NOEXCEPT { return __table_.load_factor(); }
2112  _LIBCPP_HIDE_FROM_ABI float max_load_factor() const _NOEXCEPT { return __table_.max_load_factor(); }
2113  _LIBCPP_HIDE_FROM_ABI void max_load_factor(float __mlf) { __table_.max_load_factor(__mlf); }
2114  _LIBCPP_HIDE_FROM_ABI void rehash(size_type __n) { __table_.__rehash_multi(__n); }
2115  _LIBCPP_HIDE_FROM_ABI void reserve(size_type __n) { __table_.__reserve_multi(__n); }
2116};
2117
2118#  if _LIBCPP_STD_VER >= 17
2119template <class _InputIterator,
2120          class _Hash      = hash<__iter_key_type<_InputIterator>>,
2121          class _Pred      = equal_to<__iter_key_type<_InputIterator>>,
2122          class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
2123          class            = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
2124          class            = enable_if_t<!__is_allocator<_Hash>::value>,
2125          class            = enable_if_t<!is_integral<_Hash>::value>,
2126          class            = enable_if_t<!__is_allocator<_Pred>::value>,
2127          class            = enable_if_t<__is_allocator<_Allocator>::value>>
2128unordered_multimap(_InputIterator,
2129                   _InputIterator,
2130                   typename allocator_traits<_Allocator>::size_type = 0,
2131                   _Hash                                            = _Hash(),
2132                   _Pred                                            = _Pred(),
2133                   _Allocator                                       = _Allocator())
2134    -> unordered_multimap<__iter_key_type<_InputIterator>,
2135                          __iter_mapped_type<_InputIterator>,
2136                          _Hash,
2137                          _Pred,
2138                          _Allocator>;
2139
2140#    if _LIBCPP_STD_VER >= 23
2141template <ranges::input_range _Range,
2142          class _Hash      = hash<__range_key_type<_Range>>,
2143          class _Pred      = equal_to<__range_key_type<_Range>>,
2144          class _Allocator = allocator<__range_to_alloc_type<_Range>>,
2145          class            = enable_if_t<!__is_allocator<_Hash>::value>,
2146          class            = enable_if_t<!is_integral<_Hash>::value>,
2147          class            = enable_if_t<!__is_allocator<_Pred>::value>,
2148          class            = enable_if_t<__is_allocator<_Allocator>::value>>
2149unordered_multimap(from_range_t,
2150                   _Range&&,
2151                   typename allocator_traits<_Allocator>::size_type = 0,
2152                   _Hash                                            = _Hash(),
2153                   _Pred                                            = _Pred(),
2154                   _Allocator                                       = _Allocator())
2155    -> unordered_multimap<__range_key_type<_Range>, __range_mapped_type<_Range>, _Hash, _Pred, _Allocator>;
2156#    endif
2157
2158template <class _Key,
2159          class _Tp,
2160          class _Hash      = hash<remove_const_t<_Key>>,
2161          class _Pred      = equal_to<remove_const_t<_Key>>,
2162          class _Allocator = allocator<pair<const _Key, _Tp>>,
2163          class            = enable_if_t<!__is_allocator<_Hash>::value>,
2164          class            = enable_if_t<!is_integral<_Hash>::value>,
2165          class            = enable_if_t<!__is_allocator<_Pred>::value>,
2166          class            = enable_if_t<__is_allocator<_Allocator>::value>>
2167unordered_multimap(
2168    initializer_list<pair<_Key, _Tp>>,
2169    typename allocator_traits<_Allocator>::size_type = 0,
2170    _Hash                                            = _Hash(),
2171    _Pred                                            = _Pred(),
2172    _Allocator = _Allocator()) -> unordered_multimap<remove_const_t<_Key>, _Tp, _Hash, _Pred, _Allocator>;
2173
2174template <class _InputIterator,
2175          class _Allocator,
2176          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
2177          class = enable_if_t<__is_allocator<_Allocator>::value>>
2178unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
2179    -> unordered_multimap<__iter_key_type<_InputIterator>,
2180                          __iter_mapped_type<_InputIterator>,
2181                          hash<__iter_key_type<_InputIterator>>,
2182                          equal_to<__iter_key_type<_InputIterator>>,
2183                          _Allocator>;
2184
2185template <class _InputIterator,
2186          class _Allocator,
2187          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
2188          class = enable_if_t<__is_allocator<_Allocator>::value>>
2189unordered_multimap(_InputIterator, _InputIterator, _Allocator)
2190    -> unordered_multimap<__iter_key_type<_InputIterator>,
2191                          __iter_mapped_type<_InputIterator>,
2192                          hash<__iter_key_type<_InputIterator>>,
2193                          equal_to<__iter_key_type<_InputIterator>>,
2194                          _Allocator>;
2195
2196template <class _InputIterator,
2197          class _Hash,
2198          class _Allocator,
2199          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
2200          class = enable_if_t<!__is_allocator<_Hash>::value>,
2201          class = enable_if_t<!is_integral<_Hash>::value>,
2202          class = enable_if_t<__is_allocator<_Allocator>::value>>
2203unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
2204    -> unordered_multimap<__iter_key_type<_InputIterator>,
2205                          __iter_mapped_type<_InputIterator>,
2206                          _Hash,
2207                          equal_to<__iter_key_type<_InputIterator>>,
2208                          _Allocator>;
2209
2210#    if _LIBCPP_STD_VER >= 23
2211
2212template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
2213unordered_multimap(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Allocator)
2214    -> unordered_multimap<__range_key_type<_Range>,
2215                          __range_mapped_type<_Range>,
2216                          hash<__range_key_type<_Range>>,
2217                          equal_to<__range_key_type<_Range>>,
2218                          _Allocator>;
2219
2220template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
2221unordered_multimap(from_range_t, _Range&&, _Allocator)
2222    -> unordered_multimap<__range_key_type<_Range>,
2223                          __range_mapped_type<_Range>,
2224                          hash<__range_key_type<_Range>>,
2225                          equal_to<__range_key_type<_Range>>,
2226                          _Allocator>;
2227
2228template <ranges::input_range _Range,
2229          class _Hash,
2230          class _Allocator,
2231          class = enable_if_t<!__is_allocator<_Hash>::value>,
2232          class = enable_if_t<!is_integral<_Hash>::value>,
2233          class = enable_if_t<__is_allocator<_Allocator>::value>>
2234unordered_multimap(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
2235    -> unordered_multimap<__range_key_type<_Range>,
2236                          __range_mapped_type<_Range>,
2237                          _Hash,
2238                          equal_to<__range_key_type<_Range>>,
2239                          _Allocator>;
2240
2241#    endif
2242
2243template <class _Key, class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
2244unordered_multimap(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Allocator)
2245    -> unordered_multimap<remove_const_t<_Key>,
2246                          _Tp,
2247                          hash<remove_const_t<_Key>>,
2248                          equal_to<remove_const_t<_Key>>,
2249                          _Allocator>;
2250
2251template <class _Key, class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
2252unordered_multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)
2253    -> unordered_multimap<remove_const_t<_Key>,
2254                          _Tp,
2255                          hash<remove_const_t<_Key>>,
2256                          equal_to<remove_const_t<_Key>>,
2257                          _Allocator>;
2258
2259template <class _Key,
2260          class _Tp,
2261          class _Hash,
2262          class _Allocator,
2263          class = enable_if_t<!__is_allocator<_Hash>::value>,
2264          class = enable_if_t<!is_integral<_Hash>::value>,
2265          class = enable_if_t<__is_allocator<_Allocator>::value>>
2266unordered_multimap(
2267    initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
2268    -> unordered_multimap<remove_const_t<_Key>, _Tp, _Hash, equal_to<remove_const_t<_Key>>, _Allocator>;
2269#  endif
2270
2271template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2272unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
2273    size_type __n, const hasher& __hf, const key_equal& __eql)
2274    : __table_(__hf, __eql) {
2275  __table_.__rehash_multi(__n);
2276}
2277
2278template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2279unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
2280    size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
2281    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
2282  __table_.__rehash_multi(__n);
2283}
2284
2285template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2286template <class _InputIterator>
2287unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(_InputIterator __first, _InputIterator __last) {
2288  insert(__first, __last);
2289}
2290
2291template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2292template <class _InputIterator>
2293unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
2294    _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const key_equal& __eql)
2295    : __table_(__hf, __eql) {
2296  __table_.__rehash_multi(__n);
2297  insert(__first, __last);
2298}
2299
2300template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2301template <class _InputIterator>
2302unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
2303    _InputIterator __first,
2304    _InputIterator __last,
2305    size_type __n,
2306    const hasher& __hf,
2307    const key_equal& __eql,
2308    const allocator_type& __a)
2309    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
2310  __table_.__rehash_multi(__n);
2311  insert(__first, __last);
2312}
2313
2314template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2315inline unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(const allocator_type& __a)
2316    : __table_(typename __table::allocator_type(__a)) {}
2317
2318template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2319unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(const unordered_multimap& __u)
2320    : __table_(__u.__table_) {
2321  __table_.__rehash_multi(__u.bucket_count());
2322  insert(__u.begin(), __u.end());
2323}
2324
2325template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2326unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
2327    const unordered_multimap& __u, const allocator_type& __a)
2328    : __table_(__u.__table_, typename __table::allocator_type(__a)) {
2329  __table_.__rehash_multi(__u.bucket_count());
2330  insert(__u.begin(), __u.end());
2331}
2332
2333#  ifndef _LIBCPP_CXX03_LANG
2334
2335template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2336inline unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(unordered_multimap&& __u)
2337    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
2338    : __table_(std::move(__u.__table_)) {}
2339
2340template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2341unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
2342    unordered_multimap&& __u, const allocator_type& __a)
2343    : __table_(std::move(__u.__table_), typename __table::allocator_type(__a)) {
2344  if (__a != __u.get_allocator()) {
2345    iterator __i = __u.begin();
2346    while (__u.size() != 0)
2347      __table_.__insert_multi_from_orphaned_node(std::move(__u.__table_.remove((__i++).__i_)->__get_value()));
2348  }
2349}
2350
2351template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2352unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(initializer_list<value_type> __il) {
2353  insert(__il.begin(), __il.end());
2354}
2355
2356template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2357unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
2358    initializer_list<value_type> __il, size_type __n, const hasher& __hf, const key_equal& __eql)
2359    : __table_(__hf, __eql) {
2360  __table_.__rehash_multi(__n);
2361  insert(__il.begin(), __il.end());
2362}
2363
2364template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2365unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
2366    initializer_list<value_type> __il,
2367    size_type __n,
2368    const hasher& __hf,
2369    const key_equal& __eql,
2370    const allocator_type& __a)
2371    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
2372  __table_.__rehash_multi(__n);
2373  insert(__il.begin(), __il.end());
2374}
2375
2376template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2377inline unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>&
2378unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(unordered_multimap&& __u)
2379    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) {
2380  __table_ = std::move(__u.__table_);
2381  return *this;
2382}
2383
2384template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2385inline unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>&
2386unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(initializer_list<value_type> __il) {
2387  __table_.__assign_multi(__il.begin(), __il.end());
2388  return *this;
2389}
2390
2391#  endif // _LIBCPP_CXX03_LANG
2392
2393template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2394template <class _InputIterator>
2395inline void unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::insert(_InputIterator __first, _InputIterator __last) {
2396  for (; __first != __last; ++__first)
2397    __table_.__emplace_multi(*__first);
2398}
2399
2400template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2401inline _LIBCPP_HIDE_FROM_ABI void
2402swap(unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x, unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
2403    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
2404  __x.swap(__y);
2405}
2406
2407#  if _LIBCPP_STD_VER >= 20
2408template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc, class _Predicate>
2409inline _LIBCPP_HIDE_FROM_ABI typename unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::size_type
2410erase_if(unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __c, _Predicate __pred) {
2411  return std::__libcpp_erase_if_container(__c, __pred);
2412}
2413#  endif
2414
2415template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2416_LIBCPP_HIDE_FROM_ABI bool operator==(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
2417                                      const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y) {
2418  if (__x.size() != __y.size())
2419    return false;
2420  typedef typename unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::const_iterator const_iterator;
2421  typedef pair<const_iterator, const_iterator> _EqRng;
2422  for (const_iterator __i = __x.begin(), __ex = __x.end(); __i != __ex;) {
2423    _EqRng __xeq = __x.equal_range(__i->first);
2424    _EqRng __yeq = __y.equal_range(__i->first);
2425    if (std::distance(__xeq.first, __xeq.second) != std::distance(__yeq.first, __yeq.second) ||
2426        !std::is_permutation(__xeq.first, __xeq.second, __yeq.first))
2427      return false;
2428    __i = __xeq.second;
2429  }
2430  return true;
2431}
2432
2433#  if _LIBCPP_STD_VER <= 17
2434
2435template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2436inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
2437                                             const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y) {
2438  return !(__x == __y);
2439}
2440
2441#  endif
2442
2443template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
2444struct __container_traits<unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc> > {
2445  // http://eel.is/c++draft/unord.req.except#2
2446  //  For unordered associative containers, if an exception is thrown by any operation
2447  //  other than the container's hash function from within an insert or emplace function
2448  //  inserting a single element, the insertion has no effect.
2449  static _LIBCPP_CONSTEXPR const bool __emplacement_has_strong_exception_safety_guarantee =
2450      __is_nothrow_invocable_v<_Hash, const _Key&>;
2451
2452  static _LIBCPP_CONSTEXPR const bool __reservable = true;
2453};
2454
2455_LIBCPP_END_NAMESPACE_STD
2456
2457#  if _LIBCPP_STD_VER >= 17
2458_LIBCPP_BEGIN_NAMESPACE_STD
2459namespace pmr {
2460template <class _KeyT, class _ValueT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
2461using unordered_map _LIBCPP_AVAILABILITY_PMR =
2462    std::unordered_map<_KeyT, _ValueT, _HashT, _PredT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;
2463
2464template <class _KeyT, class _ValueT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
2465using unordered_multimap _LIBCPP_AVAILABILITY_PMR =
2466    std::unordered_multimap<_KeyT, _ValueT, _HashT, _PredT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;
2467} // namespace pmr
2468_LIBCPP_END_NAMESPACE_STD
2469#  endif
2470
2471_LIBCPP_POP_MACROS
2472
2473#  if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
2474#    include <algorithm>
2475#    include <bit>
2476#    include <cmath>
2477#    include <concepts>
2478#    include <cstdlib>
2479#    include <iterator>
2480#    include <type_traits>
2481#  endif
2482#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
2483
2484#endif // _LIBCPP_UNORDERED_MAP
2485