unordered_map

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_UNORDERED_MAP
#define _LIBCPP_UNORDERED_MAP

/*

    unordered_map synopsis

#include <initializer_list>

namespace std
{

template <class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>,
          class Alloc = allocator<pair<const Key, T>>>
class unordered_map
{
public:
    // types
    typedef Key                                                        key_type;
    typedef T                                                          mapped_type;
    typedef Hash                                                       hasher;
    typedef Pred                                                       key_equal;
    typedef Alloc                                                      allocator_type;
    typedef pair<const key_type, mapped_type>                          value_type;
    typedef value_type&                                                reference;
    typedef const value_type&                                          const_reference;
    typedef typename allocator_traits<allocator_type>::pointer         pointer;
    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
    typedef typename allocator_traits<allocator_type>::size_type       size_type;
    typedef typename allocator_traits<allocator_type>::difference_type difference_type;

    typedef /unspecified/ iterator;
    typedef /unspecified/ const_iterator;
    typedef /unspecified/ local_iterator;
    typedef /unspecified/ const_local_iterator;

    typedef unspecified                             node_type;            // C++17
    typedef INSERT_RETURN_TYPE<iterator, node_type> insert_return_type;   // C++17

    unordered_map()
        noexcept(
            is_nothrow_default_constructible<hasher>::value &&
            is_nothrow_default_constructible<key_equal>::value &&
            is_nothrow_default_constructible<allocator_type>::value);
    explicit unordered_map(size_type n, const hasher& hf = hasher(),
                           const key_equal& eql = key_equal(),
                           const allocator_type& a = allocator_type());
    template <class InputIterator>
        unordered_map(InputIterator f, InputIterator l,
                      size_type n = 0, const hasher& hf = hasher(),
                      const key_equal& eql = key_equal(),
                      const allocator_type& a = allocator_type());
    template<container-compatible-range<value_type> R>
      unordered_map(from_range_t, R&& rg, size_type n = see below,
        const hasher& hf = hasher(), const key_equal& eql = key_equal(),
        const allocator_type& a = allocator_type()); // C++23

    explicit unordered_map(const allocator_type&);
    unordered_map(const unordered_map&);
    unordered_map(const unordered_map&, const Allocator&);
    unordered_map(unordered_map&&)
        noexcept(
            is_nothrow_move_constructible<hasher>::value &&
            is_nothrow_move_constructible<key_equal>::value &&
            is_nothrow_move_constructible<allocator_type>::value);
    unordered_map(unordered_map&&, const Allocator&);
    unordered_map(initializer_list<value_type>, size_type n = 0,
                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
                  const allocator_type& a = allocator_type());
    unordered_map(size_type n, const allocator_type& a)
      : unordered_map(n, hasher(), key_equal(), a) {}  // C++14
    unordered_map(size_type n, const hasher& hf, const allocator_type& a)
      : unordered_map(n, hf, key_equal(), a) {}  // C++14
    template <class InputIterator>
      unordered_map(InputIterator f, InputIterator l, size_type n, const allocator_type& a)
      : unordered_map(f, l, n, hasher(), key_equal(), a) {}  // C++14
    template <class InputIterator>
      unordered_map(InputIterator f, InputIterator l, size_type n, const hasher& hf,
        const allocator_type& a)
      : unordered_map(f, l, n, hf, key_equal(), a) {}  // C++14
    template<container-compatible-range<value_type> R>
      unordered_map(from_range_t, R&& rg, size_type n, const allocator_type& a)
        : unordered_map(from_range, std::forward<R>(rg), n, hasher(), key_equal(), a) { } // C++23
    template<container-compatible-range<value_type> R>
      unordered_map(from_range_t, R&& rg, size_type n, const hasher& hf, const allocator_type& a)
        : unordered_map(from_range, std::forward<R>(rg), n, hf, key_equal(), a) { }       // C++23
    unordered_map(initializer_list<value_type> il, size_type n, const allocator_type& a)
      : unordered_map(il, n, hasher(), key_equal(), a) {}  // C++14
    unordered_map(initializer_list<value_type> il, size_type n, const hasher& hf,
      const allocator_type& a)
      : unordered_map(il, n, hf, key_equal(), a) {}  // C++14
    ~unordered_map();
    unordered_map& operator=(const unordered_map&);
    unordered_map& operator=(unordered_map&&)
        noexcept(
            allocator_type::propagate_on_container_move_assignment::value &&
            is_nothrow_move_assignable<allocator_type>::value &&
            is_nothrow_move_assignable<hasher>::value &&
            is_nothrow_move_assignable<key_equal>::value);
    unordered_map& operator=(initializer_list<value_type>);

    allocator_type get_allocator() const noexcept;

    bool      empty() const noexcept;
    size_type size() const noexcept;
    size_type max_size() const noexcept;

    iterator       begin() noexcept;
    iterator       end() noexcept;
    const_iterator begin()  const noexcept;
    const_iterator end()    const noexcept;
    const_iterator cbegin() const noexcept;
    const_iterator cend()   const noexcept;

    template <class... Args>
        pair<iterator, bool> emplace(Args&&... args);
    template <class... Args>
        iterator emplace_hint(const_iterator position, Args&&... args);
    pair<iterator, bool> insert(const value_type& obj);
    template <class P>
        pair<iterator, bool> insert(P&& obj);
    iterator insert(const_iterator hint, const value_type& obj);
    template <class P>
        iterator insert(const_iterator hint, P&& obj);
    template <class InputIterator>
        void insert(InputIterator first, InputIterator last);
    template<container-compatible-range<value_type> R>
      void insert_range(R&& rg);                                                      // C++23
    void insert(initializer_list<value_type>);

    node_type extract(const_iterator position);                                       // C++17
    node_type extract(const key_type& x);                                             // C++17
    insert_return_type insert(node_type&& nh);                                        // C++17
    iterator           insert(const_iterator hint, node_type&& nh);                   // C++17

    template <class... Args>
        pair<iterator, bool> try_emplace(const key_type& k, Args&&... args);          // C++17
    template <class... Args>
        pair<iterator, bool> try_emplace(key_type&& k, Args&&... args);               // C++17
    template <class... Args>
        iterator try_emplace(const_iterator hint, const key_type& k, Args&&... args); // C++17
    template <class... Args>
        iterator try_emplace(const_iterator hint, key_type&& k, Args&&... args);      // C++17
    template <class M>
        pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj);            // C++17
    template <class M>
        pair<iterator, bool> insert_or_assign(key_type&& k, M&& obj);                 // C++17
    template <class M>
        iterator insert_or_assign(const_iterator hint, const key_type& k, M&& obj);   // C++17
    template <class M>
        iterator insert_or_assign(const_iterator hint, key_type&& k, M&& obj);        // C++17

    iterator erase(const_iterator position);
    iterator erase(iterator position);  // C++14
    size_type erase(const key_type& k);
    iterator erase(const_iterator first, const_iterator last);
    void clear() noexcept;

    template<class H2, class P2>
      void merge(unordered_map<Key, T, H2, P2, Allocator>& source);         // C++17
    template<class H2, class P2>
      void merge(unordered_map<Key, T, H2, P2, Allocator>&& source);        // C++17
    template<class H2, class P2>
      void merge(unordered_multimap<Key, T, H2, P2, Allocator>& source);    // C++17
    template<class H2, class P2>
      void merge(unordered_multimap<Key, T, H2, P2, Allocator>&& source);   // C++17

    void swap(unordered_map&)
        noexcept(
            (!allocator_type::propagate_on_container_swap::value ||
             __is_nothrow_swappable<allocator_type>::value) &&
            __is_nothrow_swappable<hasher>::value &&
            __is_nothrow_swappable<key_equal>::value);

    hasher hash_function() const;
    key_equal key_eq() const;

    iterator       find(const key_type& k);
    const_iterator find(const key_type& k) const;
    template<typename K>
        iterator find(const K& x);              // C++20
    template<typename K>
        const_iterator find(const K& x) const;  // C++20
    size_type count(const key_type& k) const;
    template<typename K>
        size_type count(const K& k) const; // C++20
    bool contains(const key_type& k) const; // C++20
    template<typename K>
        bool contains(const K& k) const; // C++20
    pair<iterator, iterator>             equal_range(const key_type& k);
    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
    template<typename K>
        pair<iterator, iterator>             equal_range(const K& k); // C++20
    template<typename K>
        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20

    mapped_type& operator[](const key_type& k);
    mapped_type& operator[](key_type&& k);

    mapped_type&       at(const key_type& k);
    const mapped_type& at(const key_type& k) const;

    size_type bucket_count() const noexcept;
    size_type max_bucket_count() const noexcept;

    size_type bucket_size(size_type n) const;
    size_type bucket(const key_type& k) const;

    local_iterator       begin(size_type n);
    local_iterator       end(size_type n);
    const_local_iterator begin(size_type n) const;
    const_local_iterator end(size_type n) const;
    const_local_iterator cbegin(size_type n) const;
    const_local_iterator cend(size_type n) const;

    float load_factor() const noexcept;
    float max_load_factor() const noexcept;
    void max_load_factor(float z);
    void rehash(size_type n);
    void reserve(size_type n);
};

template<class InputIterator,
    class Hash = hash<iter_key_t<InputIterator>>, class Pred = equal_to<iter_key_t<InputIterator>>,
    class Allocator = allocator<iter_to_alloc_t<InputIterator>>>
unordered_map(InputIterator, InputIterator, typename see below::size_type = see below,
    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
  -> unordered_map<iter_key_t<InputIterator>, iter_value_t<InputIterator>, Hash, Pred,
    Allocator>; // C++17

template<ranges::input_range R, class Hash = hash<range-key-type<R>>,
         class Pred = equal_to<range-key-type<R>>,
         class Allocator = allocator<range-to-alloc-type<R>>>
  unordered_map(from_range_t, R&&, typename see below::size_type = see below,
                Hash = Hash(), Pred = Pred(), Allocator = Allocator())
    -> unordered_map<range-key-type<R>, range-mapped-type<R>, Hash, Pred, Allocator>; // C++23

template<class Key, class T, class Hash = hash<Key>,
    class Pred = equal_to<Key>, class Allocator = allocator<pair<const Key, T>>>
unordered_map(initializer_list<pair<const Key, T>>, typename see below::size_type = see below,
    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
  -> unordered_map<Key, T, Hash, Pred, Allocator>; // C++17

template<class InputIterator, class Allocator>
unordered_map(InputIterator, InputIterator, typename see below::size_type, Allocator)
  -> unordered_map<iter_key_t<InputIterator>, iter_val_t<InputIterator>,
        hash<iter_key_t<InputIterator>>, equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17

template<class InputIterator, class Allocator>
unordered_map(InputIterator, InputIterator, Allocator)
  -> unordered_map<iter_key_t<InputIterator>, iter_val_t<InputIterator>,
        hash<iter_key_t<InputIterator>>, equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17

template<class InputIterator, class Hash, class Allocator>
unordered_map(InputIterator, InputIterator, typename see below::size_type, Hash, Allocator)
  -> unordered_map<iter_key_t<InputIterator>, iter_val_t<InputIterator>, Hash,
          equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17

template<ranges::input_range R, class Allocator>
  unordered_map(from_range_t, R&&, typename see below::size_type, Allocator)
    -> unordered_map<range-key-type<R>, range-mapped-type<R>, hash<range-key-type<R>>,
                      equal_to<range-key-type<R>>, Allocator>;   // C++23

template<ranges::input_range R, class Allocator>
  unordered_map(from_range_t, R&&, Allocator)
    -> unordered_map<range-key-type<R>, range-mapped-type<R>, hash<range-key-type<R>>,
                      equal_to<range-key-type<R>>, Allocator>;   // C++23

template<ranges::input_range R, class Hash, class Allocator>
  unordered_map(from_range_t, R&&, typename see below::size_type, Hash, Allocator)
    -> unordered_map<range-key-type<R>, range-mapped-type<R>, Hash,
                      equal_to<range-key-type<R>>, Allocator>;   // C++23

template<class Key, class T, typename Allocator>
unordered_map(initializer_list<pair<const Key, T>>, typename see below::size_type, Allocator)
  -> unordered_map<Key, T, hash<Key>, equal_to<Key>, Allocator>; // C++17

template<class Key, class T, typename Allocator>
unordered_map(initializer_list<pair<const Key, T>>, Allocator)
  -> unordered_map<Key, T, hash<Key>, equal_to<Key>, Allocator>; // C++17

template<class Key, class T, class Hash, class Allocator>
unordered_map(initializer_list<pair<const Key, T>>, typename see below::size_type, Hash, Allocator)
  -> unordered_map<Key, T, Hash, equal_to<Key>, Allocator>; // C++17

template <class Key, class T, class Hash, class Pred, class Alloc>
    void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x,
              unordered_map<Key, T, Hash, Pred, Alloc>& y)
              noexcept(noexcept(x.swap(y)));

template <class Key, class T, class Hash, class Pred, class Alloc>
    bool
    operator==(const unordered_map<Key, T, Hash, Pred, Alloc>& x,
               const unordered_map<Key, T, Hash, Pred, Alloc>& y);

template <class Key, class T, class Hash, class Pred, class Alloc>
    bool
    operator!=(const unordered_map<Key, T, Hash, Pred, Alloc>& x,
               const unordered_map<Key, T, Hash, Pred, Alloc>& y); // Removed in C++20

template <class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>,
          class Alloc = allocator<pair<const Key, T>>>
class unordered_multimap
{
public:
    // types
    typedef Key                                                        key_type;
    typedef T                                                          mapped_type;
    typedef Hash                                                       hasher;
    typedef Pred                                                       key_equal;
    typedef Alloc                                                      allocator_type;
    typedef pair<const key_type, mapped_type>                          value_type;
    typedef value_type&                                                reference;
    typedef const value_type&                                          const_reference;
    typedef typename allocator_traits<allocator_type>::pointer         pointer;
    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
    typedef typename allocator_traits<allocator_type>::size_type       size_type;
    typedef typename allocator_traits<allocator_type>::difference_type difference_type;

    typedef /unspecified/ iterator;
    typedef /unspecified/ const_iterator;
    typedef /unspecified/ local_iterator;
    typedef /unspecified/ const_local_iterator;

    typedef unspecified node_type;    // C++17

    unordered_multimap()
        noexcept(
            is_nothrow_default_constructible<hasher>::value &&
            is_nothrow_default_constructible<key_equal>::value &&
            is_nothrow_default_constructible<allocator_type>::value);
    explicit unordered_multimap(size_type n, const hasher& hf = hasher(),
                           const key_equal& eql = key_equal(),
                           const allocator_type& a = allocator_type());
    template <class InputIterator>
        unordered_multimap(InputIterator f, InputIterator l,
                      size_type n = 0, const hasher& hf = hasher(),
                      const key_equal& eql = key_equal(),
                      const allocator_type& a = allocator_type());
    template<container-compatible-range<value_type> R>
      unordered_multimap(from_range_t, R&& rg, size_type n = see below,
        const hasher& hf = hasher(), const key_equal& eql = key_equal(),
        const allocator_type& a = allocator_type()); // C++23
    explicit unordered_multimap(const allocator_type&);
    unordered_multimap(const unordered_multimap&);
    unordered_multimap(const unordered_multimap&, const Allocator&);
    unordered_multimap(unordered_multimap&&)
        noexcept(
            is_nothrow_move_constructible<hasher>::value &&
            is_nothrow_move_constructible<key_equal>::value &&
            is_nothrow_move_constructible<allocator_type>::value);
    unordered_multimap(unordered_multimap&&, const Allocator&);
    unordered_multimap(initializer_list<value_type>, size_type n = 0,
                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
                  const allocator_type& a = allocator_type());
    unordered_multimap(size_type n, const allocator_type& a)
      : unordered_multimap(n, hasher(), key_equal(), a) {}  // C++14
    unordered_multimap(size_type n, const hasher& hf, const allocator_type& a)
      : unordered_multimap(n, hf, key_equal(), a) {}  // C++14
    template <class InputIterator>
      unordered_multimap(InputIterator f, InputIterator l, size_type n, const allocator_type& a)
      : unordered_multimap(f, l, n, hasher(), key_equal(), a) {}  // C++14
    template <class InputIterator>
      unordered_multimap(InputIterator f, InputIterator l, size_type n, const hasher& hf,
        const allocator_type& a)
      : unordered_multimap(f, l, n, hf, key_equal(), a) {}  // C++14
    template<container-compatible-range<value_type> R>
      unordered_multimap(from_range_t, R&& rg, size_type n, const allocator_type& a)
        : unordered_multimap(from_range, std::forward<R>(rg), n, hasher(), key_equal(), a) { } // C++23
    template<container-compatible-range<value_type> R>
      unordered_multimap(from_range_t, R&& rg, size_type n, const hasher& hf, const allocator_type& a)
        : unordered_multimap(from_range, std::forward<R>(rg), n, hf, key_equal(), a) { }       // C++23
    unordered_multimap(initializer_list<value_type> il, size_type n, const allocator_type& a)
      : unordered_multimap(il, n, hasher(), key_equal(), a) {}  // C++14
    unordered_multimap(initializer_list<value_type> il, size_type n, const hasher& hf,
      const allocator_type& a)
      : unordered_multimap(il, n, hf, key_equal(), a) {}  // C++14
    ~unordered_multimap();
    unordered_multimap& operator=(const unordered_multimap&);
    unordered_multimap& operator=(unordered_multimap&&)
        noexcept(
            allocator_type::propagate_on_container_move_assignment::value &&
            is_nothrow_move_assignable<allocator_type>::value &&
            is_nothrow_move_assignable<hasher>::value &&
            is_nothrow_move_assignable<key_equal>::value);
    unordered_multimap& operator=(initializer_list<value_type>);

    allocator_type get_allocator() const noexcept;

    bool      empty() const noexcept;
    size_type size() const noexcept;
    size_type max_size() const noexcept;

    iterator       begin() noexcept;
    iterator       end() noexcept;
    const_iterator begin()  const noexcept;
    const_iterator end()    const noexcept;
    const_iterator cbegin() const noexcept;
    const_iterator cend()   const noexcept;

    template <class... Args>
        iterator emplace(Args&&... args);
    template <class... Args>
        iterator emplace_hint(const_iterator position, Args&&... args);
    iterator insert(const value_type& obj);
    template <class P>
        iterator insert(P&& obj);
    iterator insert(const_iterator hint, const value_type& obj);
    template <class P>
        iterator insert(const_iterator hint, P&& obj);
    template <class InputIterator>
        void insert(InputIterator first, InputIterator last);
    template<container-compatible-range<value_type> R>
      void insert_range(R&& rg);                               // C++23
    void insert(initializer_list<value_type>);

    node_type extract(const_iterator position);                // C++17
    node_type extract(const key_type& x);                      // C++17
    iterator insert(node_type&& nh);                           // C++17
    iterator insert(const_iterator hint, node_type&& nh);      // C++17

    iterator erase(const_iterator position);
    iterator erase(iterator position);  // C++14
    size_type erase(const key_type& k);
    iterator erase(const_iterator first, const_iterator last);
    void clear() noexcept;

    template<class H2, class P2>
      void merge(unordered_multimap<Key, T, H2, P2, Allocator>& source);    // C++17
    template<class H2, class P2>
      void merge(unordered_multimap<Key, T, H2, P2, Allocator>&& source);   // C++17
    template<class H2, class P2>
      void merge(unordered_map<Key, T, H2, P2, Allocator>& source);         // C++17
    template<class H2, class P2>
      void merge(unordered_map<Key, T, H2, P2, Allocator>&& source);        // C++17

    void swap(unordered_multimap&)
        noexcept(
            (!allocator_type::propagate_on_container_swap::value ||
             __is_nothrow_swappable<allocator_type>::value) &&
            __is_nothrow_swappable<hasher>::value &&
            __is_nothrow_swappable<key_equal>::value);

    hasher hash_function() const;
    key_equal key_eq() const;

    iterator       find(const key_type& k);
    const_iterator find(const key_type& k) const;
    template<typename K>
        iterator find(const K& x);              // C++20
    template<typename K>
        const_iterator find(const K& x) const;  // C++20
    size_type count(const key_type& k) const;
    template<typename K>
        size_type count(const K& k) const; // C++20
    bool contains(const key_type& k) const; // C++20
    template<typename K>
        bool contains(const K& k) const; // C++20
    pair<iterator, iterator>             equal_range(const key_type& k);
    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
    template<typename K>
        pair<iterator, iterator>             equal_range(const K& k); // C++20
    template<typename K>
        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20

    size_type bucket_count() const noexcept;
    size_type max_bucket_count() const noexcept;

    size_type bucket_size(size_type n) const;
    size_type bucket(const key_type& k) const;

    local_iterator       begin(size_type n);
    local_iterator       end(size_type n);
    const_local_iterator begin(size_type n) const;
    const_local_iterator end(size_type n) const;
    const_local_iterator cbegin(size_type n) const;
    const_local_iterator cend(size_type n) const;

    float load_factor() const noexcept;
    float max_load_factor() const noexcept;
    void max_load_factor(float z);
    void rehash(size_type n);
    void reserve(size_type n);
};

template<class InputIterator,
    class Hash = hash<iter_key_t<InputIterator>>, class Pred = equal_to<iter_key_t<InputIterator>>,
    class Allocator = allocator<iter_to_alloc_t<InputIterator>>>
unordered_multimap(InputIterator, InputIterator, typename see below::size_type = see below,
    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
  -> unordered_multimap<iter_key_t<InputIterator>, iter_value_t<InputIterator>, Hash, Pred,
    Allocator>; // C++17

template<ranges::input_range R, class Hash = hash<range-key-type<R>>,
         class Pred = equal_to<range-key-type<R>>,
         class Allocator = allocator<range-to-alloc-type<R>>>
  unordered_multimap(from_range_t, R&&, typename see below::size_type = see below,
                Hash = Hash(), Pred = Pred(), Allocator = Allocator())
    -> unordered_multimap<range-key-type<R>, range-mapped-type<R>, Hash, Pred, Allocator>; // C++23

template<class Key, class T, class Hash = hash<Key>,
    class Pred = equal_to<Key>, class Allocator = allocator<pair<const Key, T>>>
unordered_multimap(initializer_list<pair<const Key, T>>, typename see below::size_type = see below,
    Hash = Hash(), Pred = Pred(), Allocator = Allocator())
  -> unordered_multimap<Key, T, Hash, Pred, Allocator>; // C++17

template<class InputIterator, class Allocator>
unordered_multimap(InputIterator, InputIterator, typename see below::size_type, Allocator)
  -> unordered_multimap<iter_key_t<InputIterator>, iter_val_t<InputIterator>,
        hash<iter_key_t<InputIterator>>, equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17

template<class InputIterator, class Allocator>
unordered_multimap(InputIterator, InputIterator, Allocator)
  -> unordered_multimap<iter_key_t<InputIterator>, iter_val_t<InputIterator>,
        hash<iter_key_t<InputIterator>>, equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17

template<class InputIterator, class Hash, class Allocator>
unordered_multimap(InputIterator, InputIterator, typename see below::size_type, Hash, Allocator)
  -> unordered_multimap<iter_key_t<InputIterator>, iter_val_t<InputIterator>, Hash,
          equal_to<iter_key_t<InputIterator>>, Allocator>; // C++17

template<ranges::input_range R, class Allocator>
  unordered_multimap(from_range_t, R&&, typename see below::size_type, Allocator)
    -> unordered_multimap<range-key-type<R>, range-mapped-type<R>, hash<range-key-type<R>>,
                      equal_to<range-key-type<R>>, Allocator>;   // C++23

template<ranges::input_range R, class Allocator>
  unordered_multimap(from_range_t, R&&, Allocator)
    -> unordered_multimap<range-key-type<R>, range-mapped-type<R>, hash<range-key-type<R>>,
                      equal_to<range-key-type<R>>, Allocator>;   // C++23

template<ranges::input_range R, class Hash, class Allocator>
  unordered_multimap(from_range_t, R&&, typename see below::size_type, Hash, Allocator)
    -> unordered_multimap<range-key-type<R>, range-mapped-type<R>, Hash,
                      equal_to<range-key-type<R>>, Allocator>;   // C++23

template<class Key, class T, typename Allocator>
unordered_multimap(initializer_list<pair<const Key, T>>, typename see below::size_type, Allocator)
  -> unordered_multimap<Key, T, hash<Key>, equal_to<Key>, Allocator>; // C++17

template<class Key, class T, typename Allocator>
unordered_multimap(initializer_list<pair<const Key, T>>, Allocator)
  -> unordered_multimap<Key, T, hash<Key>, equal_to<Key>, Allocator>; // C++17

template<class Key, class T, class Hash, class Allocator>
unordered_multimap(initializer_list<pair<const Key, T>>, typename see below::size_type, Hash,
    Allocator)
  -> unordered_multimap<Key, T, Hash, equal_to<Key>, Allocator>; // C++17

template <class Key, class T, class Hash, class Pred, class Alloc>
    void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
              unordered_multimap<Key, T, Hash, Pred, Alloc>& y)
              noexcept(noexcept(x.swap(y)));

template <class K, class T, class H, class P, class A, class Predicate>
    typename unordered_map<K, T, H, P, A>::size_type
    erase_if(unordered_map<K, T, H, P, A>& c, Predicate pred);       // C++20

template <class K, class T, class H, class P, class A, class Predicate>
    typename unordered_multimap<K, T, H, P, A>::size_type
    erase_if(unordered_multimap<K, T, H, P, A>& c, Predicate pred);  // C++20

template <class Key, class T, class Hash, class Pred, class Alloc>
    bool
    operator==(const unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
               const unordered_multimap<Key, T, Hash, Pred, Alloc>& y);

template <class Key, class T, class Hash, class Pred, class Alloc>
    bool
    operator!=(const unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
               const unordered_multimap<Key, T, Hash, Pred, Alloc>& y); // Removed in C++20

}  // std

*/

#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
#  include <__cxx03/unordered_map>
#else
#  include <__algorithm/is_permutation.h>
#  include <__assert>
#  include <__config>
#  include <__functional/hash.h>
#  include <__functional/is_transparent.h>
#  include <__functional/operations.h>
#  include <__hash_table>
#  include <__iterator/distance.h>
#  include <__iterator/erase_if_container.h>
#  include <__iterator/iterator_traits.h>
#  include <__iterator/ranges_iterator_traits.h>
#  include <__memory/addressof.h>
#  include <__memory/allocator.h>
#  include <__memory/allocator_traits.h>
#  include <__memory/pointer_traits.h>
#  include <__memory/unique_ptr.h>
#  include <__memory_resource/polymorphic_allocator.h>
#  include <__new/launder.h>
#  include <__node_handle>
#  include <__ranges/concepts.h>
#  include <__ranges/container_compatible_range.h>
#  include <__ranges/from_range.h>
#  include <__type_traits/container_traits.h>
#  include <__type_traits/enable_if.h>
#  include <__type_traits/invoke.h>
#  include <__type_traits/is_allocator.h>
#  include <__type_traits/is_integral.h>
#  include <__type_traits/remove_const.h>
#  include <__type_traits/type_identity.h>
#  include <__utility/forward.h>
#  include <__utility/pair.h>
#  include <stdexcept>
#  include <tuple>
#  include <version>

// standard-mandated includes

// [iterator.range]
#  include <__iterator/access.h>
#  include <__iterator/data.h>
#  include <__iterator/empty.h>
#  include <__iterator/reverse_access.h>
#  include <__iterator/size.h>

// [unord.map.syn]
#  include <compare>
#  include <initializer_list>

#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#    pragma GCC system_header
#  endif

_LIBCPP_PUSH_MACROS
#  include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _Key,
          class _Cp,
          class _Hash,
          class _Pred,
          bool = is_empty<_Hash>::value && !__libcpp_is_final<_Hash>::value>
class __unordered_map_hasher : private _Hash {
public:
  _LIBCPP_HIDE_FROM_ABI __unordered_map_hasher() _NOEXCEPT_(is_nothrow_default_constructible<_Hash>::value) : _Hash() {}
  _LIBCPP_HIDE_FROM_ABI __unordered_map_hasher(const _Hash& __h) _NOEXCEPT_(is_nothrow_copy_constructible<_Hash>::value)
      : _Hash(__h) {}
  _LIBCPP_HIDE_FROM_ABI const _Hash& hash_function() const _NOEXCEPT { return *this; }
  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _Cp& __x) const {
    return static_cast<const _Hash&>(*this)(__x.__get_value().first);
  }
  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _Key& __x) const { return static_cast<const _Hash&>(*this)(__x); }
#  if _LIBCPP_STD_VER >= 20
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _K2& __x) const {
    return static_cast<const _Hash&>(*this)(__x);
  }
#  endif
  _LIBCPP_HIDE_FROM_ABI void swap(__unordered_map_hasher& __y) _NOEXCEPT_(__is_nothrow_swappable_v<_Hash>) {
    using std::swap;
    swap(static_cast<_Hash&>(*this), static_cast<_Hash&>(__y));
  }
};

template <class _Key, class _Cp, class _Hash, class _Pred>
class __unordered_map_hasher<_Key, _Cp, _Hash, _Pred, false> {
  _Hash __hash_;

public:
  _LIBCPP_HIDE_FROM_ABI __unordered_map_hasher() _NOEXCEPT_(is_nothrow_default_constructible<_Hash>::value)
      : __hash_() {}
  _LIBCPP_HIDE_FROM_ABI __unordered_map_hasher(const _Hash& __h) _NOEXCEPT_(is_nothrow_copy_constructible<_Hash>::value)
      : __hash_(__h) {}
  _LIBCPP_HIDE_FROM_ABI const _Hash& hash_function() const _NOEXCEPT { return __hash_; }
  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _Cp& __x) const { return __hash_(__x.__get_value().first); }
  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _Key& __x) const { return __hash_(__x); }
#  if _LIBCPP_STD_VER >= 20
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI size_t operator()(const _K2& __x) const {
    return __hash_(__x);
  }
#  endif
  _LIBCPP_HIDE_FROM_ABI void swap(__unordered_map_hasher& __y) _NOEXCEPT_(__is_nothrow_swappable_v<_Hash>) {
    using std::swap;
    swap(__hash_, __y.__hash_);
  }
};

template <class _Key, class _Cp, class _Hash, class _Pred, bool __b>
inline _LIBCPP_HIDE_FROM_ABI void
swap(__unordered_map_hasher<_Key, _Cp, _Hash, _Pred, __b>& __x,
     __unordered_map_hasher<_Key, _Cp, _Hash, _Pred, __b>& __y) _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
  __x.swap(__y);
}

template <class _Key,
          class _Cp,
          class _Pred,
          class _Hash,
          bool = is_empty<_Pred>::value && !__libcpp_is_final<_Pred>::value>
class __unordered_map_equal : private _Pred {
public:
  _LIBCPP_HIDE_FROM_ABI __unordered_map_equal() _NOEXCEPT_(is_nothrow_default_constructible<_Pred>::value) : _Pred() {}
  _LIBCPP_HIDE_FROM_ABI __unordered_map_equal(const _Pred& __p) _NOEXCEPT_(is_nothrow_copy_constructible<_Pred>::value)
      : _Pred(__p) {}
  _LIBCPP_HIDE_FROM_ABI const _Pred& key_eq() const _NOEXCEPT { return *this; }
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _Cp& __y) const {
    return static_cast<const _Pred&>(*this)(__x.__get_value().first, __y.__get_value().first);
  }
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _Key& __y) const {
    return static_cast<const _Pred&>(*this)(__x.__get_value().first, __y);
  }
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Key& __x, const _Cp& __y) const {
    return static_cast<const _Pred&>(*this)(__x, __y.__get_value().first);
  }
#  if _LIBCPP_STD_VER >= 20
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _K2& __y) const {
    return static_cast<const _Pred&>(*this)(__x.__get_value().first, __y);
  }
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _K2& __x, const _Cp& __y) const {
    return static_cast<const _Pred&>(*this)(__x, __y.__get_value().first);
  }
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Key& __x, const _K2& __y) const {
    return static_cast<const _Pred&>(*this)(__x, __y);
  }
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _K2& __x, const _Key& __y) const {
    return static_cast<const _Pred&>(*this)(__x, __y);
  }
#  endif
  _LIBCPP_HIDE_FROM_ABI void swap(__unordered_map_equal& __y) _NOEXCEPT_(__is_nothrow_swappable_v<_Pred>) {
    using std::swap;
    swap(static_cast<_Pred&>(*this), static_cast<_Pred&>(__y));
  }
};

template <class _Key, class _Cp, class _Pred, class _Hash>
class __unordered_map_equal<_Key, _Cp, _Pred, _Hash, false> {
  _Pred __pred_;

public:
  _LIBCPP_HIDE_FROM_ABI __unordered_map_equal() _NOEXCEPT_(is_nothrow_default_constructible<_Pred>::value)
      : __pred_() {}
  _LIBCPP_HIDE_FROM_ABI __unordered_map_equal(const _Pred& __p) _NOEXCEPT_(is_nothrow_copy_constructible<_Pred>::value)
      : __pred_(__p) {}
  _LIBCPP_HIDE_FROM_ABI const _Pred& key_eq() const _NOEXCEPT { return __pred_; }
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _Cp& __y) const {
    return __pred_(__x.__get_value().first, __y.__get_value().first);
  }
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _Key& __y) const {
    return __pred_(__x.__get_value().first, __y);
  }
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Key& __x, const _Cp& __y) const {
    return __pred_(__x, __y.__get_value().first);
  }
#  if _LIBCPP_STD_VER >= 20
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Cp& __x, const _K2& __y) const {
    return __pred_(__x.__get_value().first, __y);
  }
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _K2& __x, const _Cp& __y) const {
    return __pred_(__x, __y.__get_value().first);
  }
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _Key& __x, const _K2& __y) const {
    return __pred_(__x, __y);
  }
  template <typename _K2>
  _LIBCPP_HIDE_FROM_ABI bool operator()(const _K2& __x, const _Key& __y) const {
    return __pred_(__x, __y);
  }
#  endif
  _LIBCPP_HIDE_FROM_ABI void swap(__unordered_map_equal& __y) _NOEXCEPT_(__is_nothrow_swappable_v<_Pred>) {
    using std::swap;
    swap(__pred_, __y.__pred_);
  }
};

template <class _Key, class _Cp, class _Pred, class _Hash, bool __b>
inline _LIBCPP_HIDE_FROM_ABI void
swap(__unordered_map_equal<_Key, _Cp, _Pred, _Hash, __b>& __x, __unordered_map_equal<_Key, _Cp, _Pred, _Hash, __b>& __y)
    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
  __x.swap(__y);
}

template <class _Alloc>
class __hash_map_node_destructor {
  typedef _Alloc allocator_type;
  typedef allocator_traits<allocator_type> __alloc_traits;

public:
  typedef typename __alloc_traits::pointer pointer;

private:
  allocator_type& __na_;

public:
  bool __first_constructed;
  bool __second_constructed;

  __hash_map_node_destructor& operator=(const __hash_map_node_destructor&) = delete;

  _LIBCPP_HIDE_FROM_ABI explicit __hash_map_node_destructor(allocator_type& __na) _NOEXCEPT
      : __na_(__na),
        __first_constructed(false),
        __second_constructed(false) {}

#  ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI __hash_map_node_destructor(__hash_node_destructor<allocator_type>&& __x) _NOEXCEPT
      : __na_(__x.__na_),
        __first_constructed(__x.__value_constructed),
        __second_constructed(__x.__value_constructed) {
    __x.__value_constructed = false;
  }
#  else  // _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI __hash_map_node_destructor(const __hash_node_destructor<allocator_type>& __x)
      : __na_(__x.__na_), __first_constructed(__x.__value_constructed), __second_constructed(__x.__value_constructed) {
    const_cast<bool&>(__x.__value_constructed) = false;
  }
#  endif // _LIBCPP_CXX03_LANG

  _LIBCPP_HIDE_FROM_ABI void operator()(pointer __p) _NOEXCEPT {
    if (__second_constructed)
      __alloc_traits::destroy(__na_, std::addressof(__p->__get_value().__get_value().second));
    if (__first_constructed)
      __alloc_traits::destroy(__na_, std::addressof(__p->__get_value().__get_value().first));
    if (__p)
      __alloc_traits::deallocate(__na_, __p, 1);
  }
};

#  ifndef _LIBCPP_CXX03_LANG
template <class _Key, class _Tp>
struct _LIBCPP_STANDALONE_DEBUG __hash_value_type {
  typedef _Key key_type;
  typedef _Tp mapped_type;
  typedef pair<const key_type, mapped_type> value_type;
  typedef pair<key_type&, mapped_type&> __nc_ref_pair_type;
  typedef pair<key_type&&, mapped_type&&> __nc_rref_pair_type;

private:
  value_type __cc_;

public:
  _LIBCPP_HIDE_FROM_ABI value_type& __get_value() {
#    if _LIBCPP_STD_VER >= 17
    return *std::launder(std::addressof(__cc_));
#    else
    return __cc_;
#    endif
  }

  _LIBCPP_HIDE_FROM_ABI const value_type& __get_value() const {
#    if _LIBCPP_STD_VER >= 17
    return *std::launder(std::addressof(__cc_));
#    else
    return __cc_;
#    endif
  }

  _LIBCPP_HIDE_FROM_ABI __nc_ref_pair_type __ref() {
    value_type& __v = __get_value();
    return __nc_ref_pair_type(const_cast<key_type&>(__v.first), __v.second);
  }

  _LIBCPP_HIDE_FROM_ABI __nc_rref_pair_type __move() {
    value_type& __v = __get_value();
    return __nc_rref_pair_type(std::move(const_cast<key_type&>(__v.first)), std::move(__v.second));
  }

  _LIBCPP_HIDE_FROM_ABI __hash_value_type& operator=(const __hash_value_type& __v) {
    __ref() = __v.__get_value();
    return *this;
  }

  _LIBCPP_HIDE_FROM_ABI __hash_value_type& operator=(__hash_value_type&& __v) {
    __ref() = __v.__move();
    return *this;
  }

  template <class _ValueTp, __enable_if_t<__is_same_uncvref<_ValueTp, value_type>::value, int> = 0>
  _LIBCPP_HIDE_FROM_ABI __hash_value_type& operator=(_ValueTp&& __v) {
    __ref() = std::forward<_ValueTp>(__v);
    return *this;
  }

  __hash_value_type(const __hash_value_type& __v) = delete;
  __hash_value_type(__hash_value_type&& __v)      = delete;
  template <class... _Args>
  explicit __hash_value_type(_Args&&... __args) = delete;

  ~__hash_value_type() = delete;
};

#  else

template <class _Key, class _Tp>
struct __hash_value_type {
  typedef _Key key_type;
  typedef _Tp mapped_type;
  typedef pair<const key_type, mapped_type> value_type;

private:
  value_type __cc_;

public:
  _LIBCPP_HIDE_FROM_ABI value_type& __get_value() { return __cc_; }
  _LIBCPP_HIDE_FROM_ABI const value_type& __get_value() const { return __cc_; }

  ~__hash_value_type() = delete;
};

#  endif

template <class _HashIterator>
class _LIBCPP_TEMPLATE_VIS __hash_map_iterator {
  _HashIterator __i_;

  typedef __hash_node_types_from_iterator<_HashIterator> _NodeTypes;

public:
  typedef forward_iterator_tag iterator_category;
  typedef typename _NodeTypes::__map_value_type value_type;
  typedef typename _NodeTypes::difference_type difference_type;
  typedef value_type& reference;
  typedef typename _NodeTypes::__map_value_type_pointer pointer;

  _LIBCPP_HIDE_FROM_ABI __hash_map_iterator() _NOEXCEPT {}

  _LIBCPP_HIDE_FROM_ABI __hash_map_iterator(_HashIterator __i) _NOEXCEPT : __i_(__i) {}

  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __i_->__get_value(); }
  _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return pointer_traits<pointer>::pointer_to(__i_->__get_value()); }

  _LIBCPP_HIDE_FROM_ABI __hash_map_iterator& operator++() {
    ++__i_;
    return *this;
  }
  _LIBCPP_HIDE_FROM_ABI __hash_map_iterator operator++(int) {
    __hash_map_iterator __t(*this);
    ++(*this);
    return __t;
  }

  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __hash_map_iterator& __x, const __hash_map_iterator& __y) {
    return __x.__i_ == __y.__i_;
  }
#  if _LIBCPP_STD_VER <= 17
  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __hash_map_iterator& __x, const __hash_map_iterator& __y) {
    return __x.__i_ != __y.__i_;
  }
#  endif

  template <class, class, class, class, class>
  friend class _LIBCPP_TEMPLATE_VIS unordered_map;
  template <class, class, class, class, class>
  friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
  template <class>
  friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
  template <class>
  friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
  template <class>
  friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
};

template <class _HashIterator>
class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator {
  _HashIterator __i_;

  typedef __hash_node_types_from_iterator<_HashIterator> _NodeTypes;

public:
  typedef forward_iterator_tag iterator_category;
  typedef typename _NodeTypes::__map_value_type value_type;
  typedef typename _NodeTypes::difference_type difference_type;
  typedef const value_type& reference;
  typedef typename _NodeTypes::__const_map_value_type_pointer pointer;

  _LIBCPP_HIDE_FROM_ABI __hash_map_const_iterator() _NOEXCEPT {}

  _LIBCPP_HIDE_FROM_ABI __hash_map_const_iterator(_HashIterator __i) _NOEXCEPT : __i_(__i) {}
  _LIBCPP_HIDE_FROM_ABI
  __hash_map_const_iterator(__hash_map_iterator<typename _HashIterator::__non_const_iterator> __i) _NOEXCEPT
      : __i_(__i.__i_) {}

  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __i_->__get_value(); }
  _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return pointer_traits<pointer>::pointer_to(__i_->__get_value()); }

  _LIBCPP_HIDE_FROM_ABI __hash_map_const_iterator& operator++() {
    ++__i_;
    return *this;
  }
  _LIBCPP_HIDE_FROM_ABI __hash_map_const_iterator operator++(int) {
    __hash_map_const_iterator __t(*this);
    ++(*this);
    return __t;
  }

  friend _LIBCPP_HIDE_FROM_ABI bool
  operator==(const __hash_map_const_iterator& __x, const __hash_map_const_iterator& __y) {
    return __x.__i_ == __y.__i_;
  }
#  if _LIBCPP_STD_VER <= 17
  friend _LIBCPP_HIDE_FROM_ABI bool
  operator!=(const __hash_map_const_iterator& __x, const __hash_map_const_iterator& __y) {
    return __x.__i_ != __y.__i_;
  }
#  endif

  template <class, class, class, class, class>
  friend class _LIBCPP_TEMPLATE_VIS unordered_map;
  template <class, class, class, class, class>
  friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
  template <class>
  friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
  template <class>
  friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
};

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
class unordered_multimap;

template <class _Key,
          class _Tp,
          class _Hash  = hash<_Key>,
          class _Pred  = equal_to<_Key>,
          class _Alloc = allocator<pair<const _Key, _Tp> > >
class _LIBCPP_TEMPLATE_VIS unordered_map {
public:
  // types
  typedef _Key key_type;
  typedef _Tp mapped_type;
  typedef __type_identity_t<_Hash> hasher;
  typedef __type_identity_t<_Pred> key_equal;
  typedef __type_identity_t<_Alloc> allocator_type;
  typedef pair<const key_type, mapped_type> value_type;
  typedef value_type& reference;
  typedef const value_type& const_reference;
  static_assert(is_same<value_type, typename allocator_type::value_type>::value,
                "Allocator::value_type must be same type as value_type");

private:
  typedef __hash_value_type<key_type, mapped_type> __value_type;
  typedef __unordered_map_hasher<key_type, __value_type, hasher, key_equal> __hasher;
  typedef __unordered_map_equal<key_type, __value_type, key_equal, hasher> __key_equal;
  typedef __rebind_alloc<allocator_traits<allocator_type>, __value_type> __allocator_type;

  typedef __hash_table<__value_type, __hasher, __key_equal, __allocator_type> __table;

  __table __table_;

  typedef typename __table::_NodeTypes _NodeTypes;
  typedef typename __table::__node_pointer __node_pointer;
  typedef typename __table::__node_const_pointer __node_const_pointer;
  typedef typename __table::__node_traits __node_traits;
  typedef typename __table::__node_allocator __node_allocator;
  typedef typename __table::__node __node;
  typedef __hash_map_node_destructor<__node_allocator> _Dp;
  typedef unique_ptr<__node, _Dp> __node_holder;
  typedef allocator_traits<allocator_type> __alloc_traits;

  static_assert(__check_valid_allocator<allocator_type>::value, "");

  static_assert(is_same<typename __table::__container_value_type, value_type>::value, "");
  static_assert(is_same<typename __table::__node_value_type, __value_type>::value, "");

public:
  typedef typename __alloc_traits::pointer pointer;
  typedef typename __alloc_traits::const_pointer const_pointer;
  typedef typename __table::size_type size_type;
  typedef typename __table::difference_type difference_type;

  typedef __hash_map_iterator<typename __table::iterator> iterator;
  typedef __hash_map_const_iterator<typename __table::const_iterator> const_iterator;
  typedef __hash_map_iterator<typename __table::local_iterator> local_iterator;
  typedef __hash_map_const_iterator<typename __table::const_local_iterator> const_local_iterator;

#  if _LIBCPP_STD_VER >= 17
  typedef __map_node_handle<__node, allocator_type> node_type;
  typedef __insert_return_type<iterator, node_type> insert_return_type;
#  endif

  template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
  friend class _LIBCPP_TEMPLATE_VIS unordered_map;
  template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
  friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;

  _LIBCPP_HIDE_FROM_ABI unordered_map() _NOEXCEPT_(is_nothrow_default_constructible<__table>::value) {}
  explicit _LIBCPP_HIDE_FROM_ABI
  unordered_map(size_type __n, const hasher& __hf = hasher(), const key_equal& __eql = key_equal());
  _LIBCPP_HIDE_FROM_ABI
  unordered_map(size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a);
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI unordered_map(_InputIterator __first, _InputIterator __last);
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI
  unordered_map(_InputIterator __first,
                _InputIterator __last,
                size_type __n,
                const hasher& __hf     = hasher(),
                const key_equal& __eql = key_equal());
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI unordered_map(
      _InputIterator __first,
      _InputIterator __last,
      size_type __n,
      const hasher& __hf,
      const key_equal& __eql,
      const allocator_type& __a);

#  if _LIBCPP_STD_VER >= 23
  template <_ContainerCompatibleRange<value_type> _Range>
  _LIBCPP_HIDE_FROM_ABI unordered_map(
      from_range_t,
      _Range&& __range,
      size_type __n             = /*implementation-defined*/ 0,
      const hasher& __hf        = hasher(),
      const key_equal& __eql    = key_equal(),
      const allocator_type& __a = allocator_type())
      : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
    if (__n > 0) {
      __table_.__rehash_unique(__n);
    }
    insert_range(std::forward<_Range>(__range));
  }
#  endif

  _LIBCPP_HIDE_FROM_ABI explicit unordered_map(const allocator_type& __a);
  _LIBCPP_HIDE_FROM_ABI unordered_map(const unordered_map& __u);
  _LIBCPP_HIDE_FROM_ABI unordered_map(const unordered_map& __u, const allocator_type& __a);
#  ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI unordered_map(unordered_map&& __u) _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
  _LIBCPP_HIDE_FROM_ABI unordered_map(unordered_map&& __u, const allocator_type& __a);
  _LIBCPP_HIDE_FROM_ABI unordered_map(initializer_list<value_type> __il);
  _LIBCPP_HIDE_FROM_ABI
  unordered_map(initializer_list<value_type> __il,
                size_type __n,
                const hasher& __hf     = hasher(),
                const key_equal& __eql = key_equal());
  _LIBCPP_HIDE_FROM_ABI unordered_map(
      initializer_list<value_type> __il,
      size_type __n,
      const hasher& __hf,
      const key_equal& __eql,
      const allocator_type& __a);
#  endif // _LIBCPP_CXX03_LANG
#  if _LIBCPP_STD_VER >= 14
  _LIBCPP_HIDE_FROM_ABI unordered_map(size_type __n, const allocator_type& __a)
      : unordered_map(__n, hasher(), key_equal(), __a) {}
  _LIBCPP_HIDE_FROM_ABI unordered_map(size_type __n, const hasher& __hf, const allocator_type& __a)
      : unordered_map(__n, __hf, key_equal(), __a) {}
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI
  unordered_map(_InputIterator __first, _InputIterator __last, size_type __n, const allocator_type& __a)
      : unordered_map(__first, __last, __n, hasher(), key_equal(), __a) {}
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI unordered_map(
      _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const allocator_type& __a)
      : unordered_map(__first, __last, __n, __hf, key_equal(), __a) {}

#    if _LIBCPP_STD_VER >= 23
  template <_ContainerCompatibleRange<value_type> _Range>
  _LIBCPP_HIDE_FROM_ABI unordered_map(from_range_t, _Range&& __range, size_type __n, const allocator_type& __a)
      : unordered_map(from_range, std::forward<_Range>(__range), __n, hasher(), key_equal(), __a) {}

  template <_ContainerCompatibleRange<value_type> _Range>
  _LIBCPP_HIDE_FROM_ABI
  unordered_map(from_range_t, _Range&& __range, size_type __n, const hasher& __hf, const allocator_type& __a)
      : unordered_map(from_range, std::forward<_Range>(__range), __n, __hf, key_equal(), __a) {}
#    endif

  _LIBCPP_HIDE_FROM_ABI unordered_map(initializer_list<value_type> __il, size_type __n, const allocator_type& __a)
      : unordered_map(__il, __n, hasher(), key_equal(), __a) {}
  _LIBCPP_HIDE_FROM_ABI
  unordered_map(initializer_list<value_type> __il, size_type __n, const hasher& __hf, const allocator_type& __a)
      : unordered_map(__il, __n, __hf, key_equal(), __a) {}
#  endif
  _LIBCPP_HIDE_FROM_ABI ~unordered_map() {
    static_assert(sizeof(std::__diagnose_unordered_container_requirements<_Key, _Hash, _Pred>(0)), "");
  }

  _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(const unordered_map& __u) {
#  ifndef _LIBCPP_CXX03_LANG
    __table_ = __u.__table_;
#  else
    if (this != std::addressof(__u)) {
      __table_.clear();
      __table_.hash_function()   = __u.__table_.hash_function();
      __table_.key_eq()          = __u.__table_.key_eq();
      __table_.max_load_factor() = __u.__table_.max_load_factor();
      __table_.__copy_assign_alloc(__u.__table_);
      insert(__u.begin(), __u.end());
    }
#  endif
    return *this;
  }
#  ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(unordered_map&& __u)
      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
  _LIBCPP_HIDE_FROM_ABI unordered_map& operator=(initializer_list<value_type> __il);
#  endif // _LIBCPP_CXX03_LANG

  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT {
    return allocator_type(__table_.__node_alloc());
  }

  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }

  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __table_.begin(); }
  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __table_.end(); }
  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __table_.begin(); }
  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __table_.end(); }
  _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return __table_.begin(); }
  _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return __table_.end(); }

  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert(const value_type& __x) { return __table_.__insert_unique(__x); }

  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator, const value_type& __x) { return insert(__x).first; }

  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI void insert(_InputIterator __first, _InputIterator __last);

#  if _LIBCPP_STD_VER >= 23
  template <_ContainerCompatibleRange<value_type> _Range>
  _LIBCPP_HIDE_FROM_ABI void insert_range(_Range&& __range) {
    for (auto&& __element : __range) {
      __table_.__insert_unique(std::forward<decltype(__element)>(__element));
    }
  }
#  endif

#  ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI void insert(initializer_list<value_type> __il) { insert(__il.begin(), __il.end()); }

  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert(value_type&& __x) {
    return __table_.__insert_unique(std::move(__x));
  }

  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator, value_type&& __x) {
    return __table_.__insert_unique(std::move(__x)).first;
  }

  template <class _Pp, __enable_if_t<is_constructible<value_type, _Pp>::value, int> = 0>
  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert(_Pp&& __x) {
    return __table_.__insert_unique(std::forward<_Pp>(__x));
  }

  template <class _Pp, __enable_if_t<is_constructible<value_type, _Pp>::value, int> = 0>
  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator, _Pp&& __x) {
    return insert(std::forward<_Pp>(__x)).first;
  }

  template <class... _Args>
  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> emplace(_Args&&... __args) {
    return __table_.__emplace_unique(std::forward<_Args>(__args)...);
  }

  template <class... _Args>
  _LIBCPP_HIDE_FROM_ABI iterator emplace_hint(const_iterator, _Args&&... __args) {
    return __table_.__emplace_unique(std::forward<_Args>(__args)...).first;
  }

#  endif // _LIBCPP_CXX03_LANG

#  if _LIBCPP_STD_VER >= 17
  template <class... _Args>
  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> try_emplace(const key_type& __k, _Args&&... __args) {
    return __table_.__emplace_unique_key_args(
        __k, piecewise_construct, std::forward_as_tuple(__k), std::forward_as_tuple(std::forward<_Args>(__args)...));
  }

  template <class... _Args>
  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> try_emplace(key_type&& __k, _Args&&... __args) {
    return __table_.__emplace_unique_key_args(
        __k,
        piecewise_construct,
        std::forward_as_tuple(std::move(__k)),
        std::forward_as_tuple(std::forward<_Args>(__args)...));
  }

  template <class... _Args>
  _LIBCPP_HIDE_FROM_ABI iterator try_emplace(const_iterator, const key_type& __k, _Args&&... __args) {
    return try_emplace(__k, std::forward<_Args>(__args)...).first;
  }

  template <class... _Args>
  _LIBCPP_HIDE_FROM_ABI iterator try_emplace(const_iterator, key_type&& __k, _Args&&... __args) {
    return try_emplace(std::move(__k), std::forward<_Args>(__args)...).first;
  }

  template <class _Vp>
  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert_or_assign(const key_type& __k, _Vp&& __v) {
    pair<iterator, bool> __res = __table_.__emplace_unique_key_args(__k, __k, std::forward<_Vp>(__v));
    if (!__res.second) {
      __res.first->second = std::forward<_Vp>(__v);
    }
    return __res;
  }

  template <class _Vp>
  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> insert_or_assign(key_type&& __k, _Vp&& __v) {
    pair<iterator, bool> __res = __table_.__emplace_unique_key_args(__k, std::move(__k), std::forward<_Vp>(__v));
    if (!__res.second) {
      __res.first->second = std::forward<_Vp>(__v);
    }
    return __res;
  }

  template <class _Vp>
  _LIBCPP_HIDE_FROM_ABI iterator insert_or_assign(const_iterator, const key_type& __k, _Vp&& __v) {
    return insert_or_assign(__k, std::forward<_Vp>(__v)).first;
  }

  template <class _Vp>
  _LIBCPP_HIDE_FROM_ABI iterator insert_or_assign(const_iterator, key_type&& __k, _Vp&& __v) {
    return insert_or_assign(std::move(__k), std::forward<_Vp>(__v)).first;
  }
#  endif // _LIBCPP_STD_VER >= 17

  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p) { return __table_.erase(__p.__i_); }
  _LIBCPP_HIDE_FROM_ABI iterator erase(iterator __p) { return __table_.erase(__p.__i_); }
  _LIBCPP_HIDE_FROM_ABI size_type erase(const key_type& __k) { return __table_.__erase_unique(__k); }
  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __first, const_iterator __last) {
    return __table_.erase(__first.__i_, __last.__i_);
  }
  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { __table_.clear(); }

#  if _LIBCPP_STD_VER >= 17
  _LIBCPP_HIDE_FROM_ABI insert_return_type insert(node_type&& __nh) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
                                        "node_type with incompatible allocator passed to unordered_map::insert()");
    return __table_.template __node_handle_insert_unique< node_type, insert_return_type>(std::move(__nh));
  }
  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __hint, node_type&& __nh) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
                                        "node_type with incompatible allocator passed to unordered_map::insert()");
    return __table_.template __node_handle_insert_unique<node_type>(__hint.__i_, std::move(__nh));
  }
  _LIBCPP_HIDE_FROM_ABI node_type extract(key_type const& __key) {
    return __table_.template __node_handle_extract<node_type>(__key);
  }
  _LIBCPP_HIDE_FROM_ABI node_type extract(const_iterator __it) {
    return __table_.template __node_handle_extract<node_type>(__it.__i_);
  }

  template <class _H2, class _P2>
  _LIBCPP_HIDE_FROM_ABI void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>& __source) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
    return __table_.__node_handle_merge_unique(__source.__table_);
  }
  template <class _H2, class _P2>
  _LIBCPP_HIDE_FROM_ABI void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>&& __source) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
    return __table_.__node_handle_merge_unique(__source.__table_);
  }
  template <class _H2, class _P2>
  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>& __source) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
    return __table_.__node_handle_merge_unique(__source.__table_);
  }
  template <class _H2, class _P2>
  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>&& __source) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
    return __table_.__node_handle_merge_unique(__source.__table_);
  }
#  endif

  _LIBCPP_HIDE_FROM_ABI void swap(unordered_map& __u) _NOEXCEPT_(__is_nothrow_swappable_v<__table>) {
    __table_.swap(__u.__table_);
  }

  _LIBCPP_HIDE_FROM_ABI hasher hash_function() const { return __table_.hash_function().hash_function(); }
  _LIBCPP_HIDE_FROM_ABI key_equal key_eq() const { return __table_.key_eq().key_eq(); }

  _LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __table_.find(__k); }
  _LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __table_.find(__k); }
#  if _LIBCPP_STD_VER >= 20
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
    return __table_.find(__k);
  }
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
    return __table_.find(__k);
  }
#  endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI size_type count(const key_type& __k) const { return __table_.__count_unique(__k); }
#  if _LIBCPP_STD_VER >= 20
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
    return __table_.__count_unique(__k);
  }
#  endif // _LIBCPP_STD_VER >= 20

#  if _LIBCPP_STD_VER >= 20
  _LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }

  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
    return find(__k) != end();
  }
#  endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const key_type& __k) {
    return __table_.__equal_range_unique(__k);
  }
  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const key_type& __k) const {
    return __table_.__equal_range_unique(__k);
  }
#  if _LIBCPP_STD_VER >= 20
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
    return __table_.__equal_range_unique(__k);
  }
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
    return __table_.__equal_range_unique(__k);
  }
#  endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI mapped_type& operator[](const key_type& __k);
#  ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI mapped_type& operator[](key_type&& __k);
#  endif

  _LIBCPP_HIDE_FROM_ABI mapped_type& at(const key_type& __k);
  _LIBCPP_HIDE_FROM_ABI const mapped_type& at(const key_type& __k) const;

  _LIBCPP_HIDE_FROM_ABI size_type bucket_count() const _NOEXCEPT { return __table_.bucket_count(); }
  _LIBCPP_HIDE_FROM_ABI size_type max_bucket_count() const _NOEXCEPT { return __table_.max_bucket_count(); }

  _LIBCPP_HIDE_FROM_ABI size_type bucket_size(size_type __n) const { return __table_.bucket_size(__n); }
  _LIBCPP_HIDE_FROM_ABI size_type bucket(const key_type& __k) const { return __table_.bucket(__k); }

  _LIBCPP_HIDE_FROM_ABI local_iterator begin(size_type __n) { return __table_.begin(__n); }
  _LIBCPP_HIDE_FROM_ABI local_iterator end(size_type __n) { return __table_.end(__n); }
  _LIBCPP_HIDE_FROM_ABI const_local_iterator begin(size_type __n) const { return __table_.cbegin(__n); }
  _LIBCPP_HIDE_FROM_ABI const_local_iterator end(size_type __n) const { return __table_.cend(__n); }
  _LIBCPP_HIDE_FROM_ABI const_local_iterator cbegin(size_type __n) const { return __table_.cbegin(__n); }
  _LIBCPP_HIDE_FROM_ABI const_local_iterator cend(size_type __n) const { return __table_.cend(__n); }

  _LIBCPP_HIDE_FROM_ABI float load_factor() const _NOEXCEPT { return __table_.load_factor(); }
  _LIBCPP_HIDE_FROM_ABI float max_load_factor() const _NOEXCEPT { return __table_.max_load_factor(); }
  _LIBCPP_HIDE_FROM_ABI void max_load_factor(float __mlf) { __table_.max_load_factor(__mlf); }
  _LIBCPP_HIDE_FROM_ABI void rehash(size_type __n) { __table_.__rehash_unique(__n); }
  _LIBCPP_HIDE_FROM_ABI void reserve(size_type __n) { __table_.__reserve_unique(__n); }

private:
#  ifdef _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI __node_holder __construct_node_with_key(const key_type& __k);
#  endif
};

#  if _LIBCPP_STD_VER >= 17
template <class _InputIterator,
          class _Hash      = hash<__iter_key_type<_InputIterator>>,
          class _Pred      = equal_to<__iter_key_type<_InputIterator>>,
          class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
          class            = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class            = enable_if_t<!__is_allocator<_Hash>::value>,
          class            = enable_if_t<!is_integral<_Hash>::value>,
          class            = enable_if_t<!__is_allocator<_Pred>::value>,
          class            = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(_InputIterator,
              _InputIterator,
              typename allocator_traits<_Allocator>::size_type = 0,
              _Hash                                            = _Hash(),
              _Pred                                            = _Pred(),
              _Allocator                                       = _Allocator())
    -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Hash, _Pred, _Allocator>;

#    if _LIBCPP_STD_VER >= 23
template <ranges::input_range _Range,
          class _Hash      = hash<__range_key_type<_Range>>,
          class _Pred      = equal_to<__range_key_type<_Range>>,
          class _Allocator = allocator<__range_to_alloc_type<_Range>>,
          class            = enable_if_t<!__is_allocator<_Hash>::value>,
          class            = enable_if_t<!is_integral<_Hash>::value>,
          class            = enable_if_t<!__is_allocator<_Pred>::value>,
          class            = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(from_range_t,
              _Range&&,
              typename allocator_traits<_Allocator>::size_type = 0,
              _Hash                                            = _Hash(),
              _Pred                                            = _Pred(),
              _Allocator                                       = _Allocator())
    -> unordered_map<__range_key_type<_Range>, __range_mapped_type<_Range>, _Hash, _Pred, _Allocator>; // C++23
#    endif

template <class _Key,
          class _Tp,
          class _Hash      = hash<remove_const_t<_Key>>,
          class _Pred      = equal_to<remove_const_t<_Key>>,
          class _Allocator = allocator<pair<const _Key, _Tp>>,
          class            = enable_if_t<!__is_allocator<_Hash>::value>,
          class            = enable_if_t<!is_integral<_Hash>::value>,
          class            = enable_if_t<!__is_allocator<_Pred>::value>,
          class            = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(initializer_list<pair<_Key, _Tp>>,
              typename allocator_traits<_Allocator>::size_type = 0,
              _Hash                                            = _Hash(),
              _Pred                                            = _Pred(),
              _Allocator = _Allocator()) -> unordered_map<remove_const_t<_Key>, _Tp, _Hash, _Pred, _Allocator>;

template <class _InputIterator,
          class _Allocator,
          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
    -> unordered_map<__iter_key_type<_InputIterator>,
                     __iter_mapped_type<_InputIterator>,
                     hash<__iter_key_type<_InputIterator>>,
                     equal_to<__iter_key_type<_InputIterator>>,
                     _Allocator>;

template <class _InputIterator,
          class _Allocator,
          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(_InputIterator, _InputIterator, _Allocator)
    -> unordered_map<__iter_key_type<_InputIterator>,
                     __iter_mapped_type<_InputIterator>,
                     hash<__iter_key_type<_InputIterator>>,
                     equal_to<__iter_key_type<_InputIterator>>,
                     _Allocator>;

template <class _InputIterator,
          class _Hash,
          class _Allocator,
          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
    -> unordered_map<__iter_key_type<_InputIterator>,
                     __iter_mapped_type<_InputIterator>,
                     _Hash,
                     equal_to<__iter_key_type<_InputIterator>>,
                     _Allocator>;

#    if _LIBCPP_STD_VER >= 23

template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Allocator)
    -> unordered_map<__range_key_type<_Range>,
                     __range_mapped_type<_Range>,
                     hash<__range_key_type<_Range>>,
                     equal_to<__range_key_type<_Range>>,
                     _Allocator>;

template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(from_range_t, _Range&&, _Allocator)
    -> unordered_map<__range_key_type<_Range>,
                     __range_mapped_type<_Range>,
                     hash<__range_key_type<_Range>>,
                     equal_to<__range_key_type<_Range>>,
                     _Allocator>;

template <ranges::input_range _Range,
          class _Hash,
          class _Allocator,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
    -> unordered_map<__range_key_type<_Range>,
                     __range_mapped_type<_Range>,
                     _Hash,
                     equal_to<__range_key_type<_Range>>,
                     _Allocator>;

#    endif

template <class _Key, class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Allocator)
    -> unordered_map<remove_const_t<_Key>, _Tp, hash<remove_const_t<_Key>>, equal_to<remove_const_t<_Key>>, _Allocator>;

template <class _Key, class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(initializer_list<pair<_Key, _Tp>>, _Allocator)
    -> unordered_map<remove_const_t<_Key>, _Tp, hash<remove_const_t<_Key>>, equal_to<remove_const_t<_Key>>, _Allocator>;

template <class _Key,
          class _Tp,
          class _Hash,
          class _Allocator,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_map(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
    -> unordered_map<remove_const_t<_Key>, _Tp, _Hash, equal_to<remove_const_t<_Key>>, _Allocator>;
#  endif

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(size_type __n, const hasher& __hf, const key_equal& __eql)
    : __table_(__hf, __eql) {
  __table_.__rehash_unique(__n);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
    size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
  __table_.__rehash_unique(__n);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(const allocator_type& __a)
    : __table_(typename __table::allocator_type(__a)) {}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
template <class _InputIterator>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(_InputIterator __first, _InputIterator __last) {
  insert(__first, __last);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
template <class _InputIterator>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
    _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const key_equal& __eql)
    : __table_(__hf, __eql) {
  __table_.__rehash_unique(__n);
  insert(__first, __last);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
template <class _InputIterator>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
    _InputIterator __first,
    _InputIterator __last,
    size_type __n,
    const hasher& __hf,
    const key_equal& __eql,
    const allocator_type& __a)
    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
  __table_.__rehash_unique(__n);
  insert(__first, __last);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(const unordered_map& __u) : __table_(__u.__table_) {
  __table_.__rehash_unique(__u.bucket_count());
  insert(__u.begin(), __u.end());
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(const unordered_map& __u, const allocator_type& __a)
    : __table_(__u.__table_, typename __table::allocator_type(__a)) {
  __table_.__rehash_unique(__u.bucket_count());
  insert(__u.begin(), __u.end());
}

#  ifndef _LIBCPP_CXX03_LANG

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(unordered_map&& __u)
    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
    : __table_(std::move(__u.__table_)) {}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(unordered_map&& __u, const allocator_type& __a)
    : __table_(std::move(__u.__table_), typename __table::allocator_type(__a)) {
  if (__a != __u.get_allocator()) {
    iterator __i = __u.begin();
    while (__u.size() != 0) {
      __table_.__emplace_unique(__u.__table_.remove((__i++).__i_)->__get_value().__move());
    }
  }
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(initializer_list<value_type> __il) {
  insert(__il.begin(), __il.end());
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
    initializer_list<value_type> __il, size_type __n, const hasher& __hf, const key_equal& __eql)
    : __table_(__hf, __eql) {
  __table_.__rehash_unique(__n);
  insert(__il.begin(), __il.end());
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
    initializer_list<value_type> __il,
    size_type __n,
    const hasher& __hf,
    const key_equal& __eql,
    const allocator_type& __a)
    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
  __table_.__rehash_unique(__n);
  insert(__il.begin(), __il.end());
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>&
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(unordered_map&& __u)
    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) {
  __table_ = std::move(__u.__table_);
  return *this;
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>&
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(initializer_list<value_type> __il) {
  __table_.__assign_unique(__il.begin(), __il.end());
  return *this;
}

#  endif // _LIBCPP_CXX03_LANG

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
template <class _InputIterator>
inline void unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::insert(_InputIterator __first, _InputIterator __last) {
  for (; __first != __last; ++__first)
    __table_.__insert_unique(*__first);
}

#  ifndef _LIBCPP_CXX03_LANG

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
_Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](const key_type& __k) {
  return __table_
      .__emplace_unique_key_args(__k, piecewise_construct, std::forward_as_tuple(__k), std::forward_as_tuple())
      .first->__get_value()
      .second;
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
_Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](key_type&& __k) {
  return __table_
      .__emplace_unique_key_args(
          __k, piecewise_construct, std::forward_as_tuple(std::move(__k)), std::forward_as_tuple())
      .first->__get_value()
      .second;
}
#  else // _LIBCPP_CXX03_LANG

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
typename unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::__node_holder
unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::__construct_node_with_key(const key_type& __k) {
  __node_allocator& __na = __table_.__node_alloc();
  __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
  __node_traits::construct(__na, std::addressof(__h->__get_value().__get_value().first), __k);
  __h.get_deleter().__first_constructed = true;
  __node_traits::construct(__na, std::addressof(__h->__get_value().__get_value().second));
  __h.get_deleter().__second_constructed = true;
  return __h;
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
_Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](const key_type& __k) {
  iterator __i = find(__k);
  if (__i != end())
    return __i->second;
  __node_holder __h        = __construct_node_with_key(__k);
  pair<iterator, bool> __r = __table_.__node_insert_unique(__h.get());
  __h.release();
  return __r.first->second;
}

#  endif // _LIBCPP_CXX03_LANG

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
_Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::at(const key_type& __k) {
  iterator __i = find(__k);
  if (__i == end())
    __throw_out_of_range("unordered_map::at: key not found");
  return __i->second;
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
const _Tp& unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::at(const key_type& __k) const {
  const_iterator __i = find(__k);
  if (__i == end())
    __throw_out_of_range("unordered_map::at: key not found");
  return __i->second;
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline _LIBCPP_HIDE_FROM_ABI void
swap(unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x, unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
  __x.swap(__y);
}

#  if _LIBCPP_STD_VER >= 20
template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc, class _Predicate>
inline _LIBCPP_HIDE_FROM_ABI typename unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::size_type
erase_if(unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __c, _Predicate __pred) {
  return std::__libcpp_erase_if_container(__c, __pred);
}
#  endif

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
_LIBCPP_HIDE_FROM_ABI bool operator==(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
                                      const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y) {
  if (__x.size() != __y.size())
    return false;
  typedef typename unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::const_iterator const_iterator;
  for (const_iterator __i = __x.begin(), __ex = __x.end(), __ey = __y.end(); __i != __ex; ++__i) {
    const_iterator __j = __y.find(__i->first);
    if (__j == __ey || !(*__i == *__j))
      return false;
  }
  return true;
}

#  if _LIBCPP_STD_VER <= 17

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
                                             const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y) {
  return !(__x == __y);
}

#  endif

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
struct __container_traits<unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc> > {
  // http://eel.is/c++draft/unord.req.except#2
  //  For unordered associative containers, if an exception is thrown by any operation
  //  other than the container's hash function from within an insert or emplace function
  //  inserting a single element, the insertion has no effect.
  static _LIBCPP_CONSTEXPR const bool __emplacement_has_strong_exception_safety_guarantee =
      __is_nothrow_invocable_v<_Hash, const _Key&>;
};

template <class _Key,
          class _Tp,
          class _Hash  = hash<_Key>,
          class _Pred  = equal_to<_Key>,
          class _Alloc = allocator<pair<const _Key, _Tp> > >
class _LIBCPP_TEMPLATE_VIS unordered_multimap {
public:
  // types
  typedef _Key key_type;
  typedef _Tp mapped_type;
  typedef __type_identity_t<_Hash> hasher;
  typedef __type_identity_t<_Pred> key_equal;
  typedef __type_identity_t<_Alloc> allocator_type;
  typedef pair<const key_type, mapped_type> value_type;
  typedef value_type& reference;
  typedef const value_type& const_reference;
  static_assert(__check_valid_allocator<allocator_type>::value, "");
  static_assert(is_same<value_type, typename allocator_type::value_type>::value,
                "Allocator::value_type must be same type as value_type");

private:
  typedef __hash_value_type<key_type, mapped_type> __value_type;
  typedef __unordered_map_hasher<key_type, __value_type, hasher, key_equal> __hasher;
  typedef __unordered_map_equal<key_type, __value_type, key_equal, hasher> __key_equal;
  typedef __rebind_alloc<allocator_traits<allocator_type>, __value_type> __allocator_type;

  typedef __hash_table<__value_type, __hasher, __key_equal, __allocator_type> __table;

  __table __table_;

  typedef typename __table::_NodeTypes _NodeTypes;
  typedef typename __table::__node_traits __node_traits;
  typedef typename __table::__node_allocator __node_allocator;
  typedef typename __table::__node __node;
  typedef __hash_map_node_destructor<__node_allocator> _Dp;
  typedef unique_ptr<__node, _Dp> __node_holder;
  typedef allocator_traits<allocator_type> __alloc_traits;
  static_assert(is_same<typename __node_traits::size_type, typename __alloc_traits::size_type>::value,
                "Allocator uses different size_type for different types");

public:
  typedef typename __alloc_traits::pointer pointer;
  typedef typename __alloc_traits::const_pointer const_pointer;
  typedef typename __table::size_type size_type;
  typedef typename __table::difference_type difference_type;

  typedef __hash_map_iterator<typename __table::iterator> iterator;
  typedef __hash_map_const_iterator<typename __table::const_iterator> const_iterator;
  typedef __hash_map_iterator<typename __table::local_iterator> local_iterator;
  typedef __hash_map_const_iterator<typename __table::const_local_iterator> const_local_iterator;

#  if _LIBCPP_STD_VER >= 17
  typedef __map_node_handle<__node, allocator_type> node_type;
#  endif

  template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
  friend class _LIBCPP_TEMPLATE_VIS unordered_map;
  template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
  friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;

  _LIBCPP_HIDE_FROM_ABI unordered_multimap() _NOEXCEPT_(is_nothrow_default_constructible<__table>::value) {}
  explicit _LIBCPP_HIDE_FROM_ABI
  unordered_multimap(size_type __n, const hasher& __hf = hasher(), const key_equal& __eql = key_equal());
  _LIBCPP_HIDE_FROM_ABI
  unordered_multimap(size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a);
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(_InputIterator __first, _InputIterator __last);
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
      _InputIterator __first,
      _InputIterator __last,
      size_type __n,
      const hasher& __hf     = hasher(),
      const key_equal& __eql = key_equal());
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
      _InputIterator __first,
      _InputIterator __last,
      size_type __n,
      const hasher& __hf,
      const key_equal& __eql,
      const allocator_type& __a);

#  if _LIBCPP_STD_VER >= 23
  template <_ContainerCompatibleRange<value_type> _Range>
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
      from_range_t,
      _Range&& __range,
      size_type __n             = /*implementation-defined*/ 0,
      const hasher& __hf        = hasher(),
      const key_equal& __eql    = key_equal(),
      const allocator_type& __a = allocator_type())
      : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
    if (__n > 0) {
      __table_.__rehash_multi(__n);
    }
    insert_range(std::forward<_Range>(__range));
  }
#  endif

  _LIBCPP_HIDE_FROM_ABI explicit unordered_multimap(const allocator_type& __a);
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(const unordered_multimap& __u);
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(const unordered_multimap& __u, const allocator_type& __a);
#  ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(unordered_multimap&& __u)
      _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(unordered_multimap&& __u, const allocator_type& __a);
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(initializer_list<value_type> __il);
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
      initializer_list<value_type> __il,
      size_type __n,
      const hasher& __hf     = hasher(),
      const key_equal& __eql = key_equal());
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
      initializer_list<value_type> __il,
      size_type __n,
      const hasher& __hf,
      const key_equal& __eql,
      const allocator_type& __a);
#  endif // _LIBCPP_CXX03_LANG
#  if _LIBCPP_STD_VER >= 14
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(size_type __n, const allocator_type& __a)
      : unordered_multimap(__n, hasher(), key_equal(), __a) {}
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(size_type __n, const hasher& __hf, const allocator_type& __a)
      : unordered_multimap(__n, __hf, key_equal(), __a) {}
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI
  unordered_multimap(_InputIterator __first, _InputIterator __last, size_type __n, const allocator_type& __a)
      : unordered_multimap(__first, __last, __n, hasher(), key_equal(), __a) {}
  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(
      _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const allocator_type& __a)
      : unordered_multimap(__first, __last, __n, __hf, key_equal(), __a) {}

#    if _LIBCPP_STD_VER >= 23
  template <_ContainerCompatibleRange<value_type> _Range>
  _LIBCPP_HIDE_FROM_ABI unordered_multimap(from_range_t, _Range&& __range, size_type __n, const allocator_type& __a)
      : unordered_multimap(from_range, std::forward<_Range>(__range), __n, hasher(), key_equal(), __a) {}

  template <_ContainerCompatibleRange<value_type> _Range>
  _LIBCPP_HIDE_FROM_ABI
  unordered_multimap(from_range_t, _Range&& __range, size_type __n, const hasher& __hf, const allocator_type& __a)
      : unordered_multimap(from_range, std::forward<_Range>(__range), __n, __hf, key_equal(), __a) {}
#    endif

  _LIBCPP_HIDE_FROM_ABI unordered_multimap(initializer_list<value_type> __il, size_type __n, const allocator_type& __a)
      : unordered_multimap(__il, __n, hasher(), key_equal(), __a) {}
  _LIBCPP_HIDE_FROM_ABI
  unordered_multimap(initializer_list<value_type> __il, size_type __n, const hasher& __hf, const allocator_type& __a)
      : unordered_multimap(__il, __n, __hf, key_equal(), __a) {}
#  endif
  _LIBCPP_HIDE_FROM_ABI ~unordered_multimap() {
    static_assert(sizeof(std::__diagnose_unordered_container_requirements<_Key, _Hash, _Pred>(0)), "");
  }

  _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(const unordered_multimap& __u) {
#  ifndef _LIBCPP_CXX03_LANG
    __table_ = __u.__table_;
#  else
    if (this != std::addressof(__u)) {
      __table_.clear();
      __table_.hash_function()   = __u.__table_.hash_function();
      __table_.key_eq()          = __u.__table_.key_eq();
      __table_.max_load_factor() = __u.__table_.max_load_factor();
      __table_.__copy_assign_alloc(__u.__table_);
      insert(__u.begin(), __u.end());
    }
#  endif
    return *this;
  }
#  ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(unordered_multimap&& __u)
      _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
  _LIBCPP_HIDE_FROM_ABI unordered_multimap& operator=(initializer_list<value_type> __il);
#  endif // _LIBCPP_CXX03_LANG

  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT {
    return allocator_type(__table_.__node_alloc());
  }

  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __table_.size() == 0; }
  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __table_.size(); }
  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __table_.max_size(); }

  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __table_.begin(); }
  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __table_.end(); }
  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __table_.begin(); }
  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __table_.end(); }
  _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return __table_.begin(); }
  _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return __table_.end(); }

  _LIBCPP_HIDE_FROM_ABI iterator insert(const value_type& __x) { return __table_.__insert_multi(__x); }

  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __x) {
    return __table_.__insert_multi(__p.__i_, __x);
  }

  template <class _InputIterator>
  _LIBCPP_HIDE_FROM_ABI void insert(_InputIterator __first, _InputIterator __last);

#  if _LIBCPP_STD_VER >= 23
  template <_ContainerCompatibleRange<value_type> _Range>
  _LIBCPP_HIDE_FROM_ABI void insert_range(_Range&& __range) {
    for (auto&& __element : __range) {
      __table_.__insert_multi(std::forward<decltype(__element)>(__element));
    }
  }
#  endif

#  ifndef _LIBCPP_CXX03_LANG
  _LIBCPP_HIDE_FROM_ABI void insert(initializer_list<value_type> __il) { insert(__il.begin(), __il.end()); }
  _LIBCPP_HIDE_FROM_ABI iterator insert(value_type&& __x) { return __table_.__insert_multi(std::move(__x)); }

  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, value_type&& __x) {
    return __table_.__insert_multi(__p.__i_, std::move(__x));
  }

  template <class _Pp, __enable_if_t<is_constructible<value_type, _Pp>::value, int> = 0>
  _LIBCPP_HIDE_FROM_ABI iterator insert(_Pp&& __x) {
    return __table_.__insert_multi(std::forward<_Pp>(__x));
  }

  template <class _Pp, __enable_if_t<is_constructible<value_type, _Pp>::value, int> = 0>
  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _Pp&& __x) {
    return __table_.__insert_multi(__p.__i_, std::forward<_Pp>(__x));
  }

  template <class... _Args>
  _LIBCPP_HIDE_FROM_ABI iterator emplace(_Args&&... __args) {
    return __table_.__emplace_multi(std::forward<_Args>(__args)...);
  }

  template <class... _Args>
  _LIBCPP_HIDE_FROM_ABI iterator emplace_hint(const_iterator __p, _Args&&... __args) {
    return __table_.__emplace_hint_multi(__p.__i_, std::forward<_Args>(__args)...);
  }
#  endif // _LIBCPP_CXX03_LANG

  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p) { return __table_.erase(__p.__i_); }
  _LIBCPP_HIDE_FROM_ABI iterator erase(iterator __p) { return __table_.erase(__p.__i_); }
  _LIBCPP_HIDE_FROM_ABI size_type erase(const key_type& __k) { return __table_.__erase_multi(__k); }
  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __first, const_iterator __last) {
    return __table_.erase(__first.__i_, __last.__i_);
  }
  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { __table_.clear(); }

#  if _LIBCPP_STD_VER >= 17
  _LIBCPP_HIDE_FROM_ABI iterator insert(node_type&& __nh) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
                                        "node_type with incompatible allocator passed to unordered_multimap::insert()");
    return __table_.template __node_handle_insert_multi<node_type>(std::move(__nh));
  }
  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __hint, node_type&& __nh) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(__nh.empty() || __nh.get_allocator() == get_allocator(),
                                        "node_type with incompatible allocator passed to unordered_multimap::insert()");
    return __table_.template __node_handle_insert_multi<node_type>(__hint.__i_, std::move(__nh));
  }
  _LIBCPP_HIDE_FROM_ABI node_type extract(key_type const& __key) {
    return __table_.template __node_handle_extract<node_type>(__key);
  }
  _LIBCPP_HIDE_FROM_ABI node_type extract(const_iterator __it) {
    return __table_.template __node_handle_extract<node_type>(__it.__i_);
  }

  template <class _H2, class _P2>
  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>& __source) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
    return __table_.__node_handle_merge_multi(__source.__table_);
  }
  template <class _H2, class _P2>
  _LIBCPP_HIDE_FROM_ABI void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>&& __source) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
    return __table_.__node_handle_merge_multi(__source.__table_);
  }
  template <class _H2, class _P2>
  _LIBCPP_HIDE_FROM_ABI void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>& __source) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
    return __table_.__node_handle_merge_multi(__source.__table_);
  }
  template <class _H2, class _P2>
  _LIBCPP_HIDE_FROM_ABI void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>&& __source) {
    _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
        __source.get_allocator() == get_allocator(), "merging container with incompatible allocator");
    return __table_.__node_handle_merge_multi(__source.__table_);
  }
#  endif

  _LIBCPP_HIDE_FROM_ABI void swap(unordered_multimap& __u) _NOEXCEPT_(__is_nothrow_swappable_v<__table>) {
    __table_.swap(__u.__table_);
  }

  _LIBCPP_HIDE_FROM_ABI hasher hash_function() const { return __table_.hash_function().hash_function(); }
  _LIBCPP_HIDE_FROM_ABI key_equal key_eq() const { return __table_.key_eq().key_eq(); }

  _LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __table_.find(__k); }
  _LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __table_.find(__k); }
#  if _LIBCPP_STD_VER >= 20
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
    return __table_.find(__k);
  }
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
    return __table_.find(__k);
  }
#  endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI size_type count(const key_type& __k) const { return __table_.__count_multi(__k); }
#  if _LIBCPP_STD_VER >= 20
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
    return __table_.__count_multi(__k);
  }
#  endif // _LIBCPP_STD_VER >= 20

#  if _LIBCPP_STD_VER >= 20
  _LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }

  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
    return find(__k) != end();
  }
#  endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const key_type& __k) {
    return __table_.__equal_range_multi(__k);
  }
  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const key_type& __k) const {
    return __table_.__equal_range_multi(__k);
  }
#  if _LIBCPP_STD_VER >= 20
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
    return __table_.__equal_range_multi(__k);
  }
  template <class _K2, enable_if_t<__is_transparent_v<hasher, _K2> && __is_transparent_v<key_equal, _K2>>* = nullptr>
  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
    return __table_.__equal_range_multi(__k);
  }
#  endif // _LIBCPP_STD_VER >= 20

  _LIBCPP_HIDE_FROM_ABI size_type bucket_count() const _NOEXCEPT { return __table_.bucket_count(); }
  _LIBCPP_HIDE_FROM_ABI size_type max_bucket_count() const _NOEXCEPT { return __table_.max_bucket_count(); }

  _LIBCPP_HIDE_FROM_ABI size_type bucket_size(size_type __n) const { return __table_.bucket_size(__n); }
  _LIBCPP_HIDE_FROM_ABI size_type bucket(const key_type& __k) const { return __table_.bucket(__k); }

  _LIBCPP_HIDE_FROM_ABI local_iterator begin(size_type __n) { return __table_.begin(__n); }
  _LIBCPP_HIDE_FROM_ABI local_iterator end(size_type __n) { return __table_.end(__n); }
  _LIBCPP_HIDE_FROM_ABI const_local_iterator begin(size_type __n) const { return __table_.cbegin(__n); }
  _LIBCPP_HIDE_FROM_ABI const_local_iterator end(size_type __n) const { return __table_.cend(__n); }
  _LIBCPP_HIDE_FROM_ABI const_local_iterator cbegin(size_type __n) const { return __table_.cbegin(__n); }
  _LIBCPP_HIDE_FROM_ABI const_local_iterator cend(size_type __n) const { return __table_.cend(__n); }

  _LIBCPP_HIDE_FROM_ABI float load_factor() const _NOEXCEPT { return __table_.load_factor(); }
  _LIBCPP_HIDE_FROM_ABI float max_load_factor() const _NOEXCEPT { return __table_.max_load_factor(); }
  _LIBCPP_HIDE_FROM_ABI void max_load_factor(float __mlf) { __table_.max_load_factor(__mlf); }
  _LIBCPP_HIDE_FROM_ABI void rehash(size_type __n) { __table_.__rehash_multi(__n); }
  _LIBCPP_HIDE_FROM_ABI void reserve(size_type __n) { __table_.__reserve_multi(__n); }
};

#  if _LIBCPP_STD_VER >= 17
template <class _InputIterator,
          class _Hash      = hash<__iter_key_type<_InputIterator>>,
          class _Pred      = equal_to<__iter_key_type<_InputIterator>>,
          class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
          class            = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class            = enable_if_t<!__is_allocator<_Hash>::value>,
          class            = enable_if_t<!is_integral<_Hash>::value>,
          class            = enable_if_t<!__is_allocator<_Pred>::value>,
          class            = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(_InputIterator,
                   _InputIterator,
                   typename allocator_traits<_Allocator>::size_type = 0,
                   _Hash                                            = _Hash(),
                   _Pred                                            = _Pred(),
                   _Allocator                                       = _Allocator())
    -> unordered_multimap<__iter_key_type<_InputIterator>,
                          __iter_mapped_type<_InputIterator>,
                          _Hash,
                          _Pred,
                          _Allocator>;

#    if _LIBCPP_STD_VER >= 23
template <ranges::input_range _Range,
          class _Hash      = hash<__range_key_type<_Range>>,
          class _Pred      = equal_to<__range_key_type<_Range>>,
          class _Allocator = allocator<__range_to_alloc_type<_Range>>,
          class            = enable_if_t<!__is_allocator<_Hash>::value>,
          class            = enable_if_t<!is_integral<_Hash>::value>,
          class            = enable_if_t<!__is_allocator<_Pred>::value>,
          class            = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(from_range_t,
                   _Range&&,
                   typename allocator_traits<_Allocator>::size_type = 0,
                   _Hash                                            = _Hash(),
                   _Pred                                            = _Pred(),
                   _Allocator                                       = _Allocator())
    -> unordered_multimap<__range_key_type<_Range>, __range_mapped_type<_Range>, _Hash, _Pred, _Allocator>;
#    endif

template <class _Key,
          class _Tp,
          class _Hash      = hash<remove_const_t<_Key>>,
          class _Pred      = equal_to<remove_const_t<_Key>>,
          class _Allocator = allocator<pair<const _Key, _Tp>>,
          class            = enable_if_t<!__is_allocator<_Hash>::value>,
          class            = enable_if_t<!is_integral<_Hash>::value>,
          class            = enable_if_t<!__is_allocator<_Pred>::value>,
          class            = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(
    initializer_list<pair<_Key, _Tp>>,
    typename allocator_traits<_Allocator>::size_type = 0,
    _Hash                                            = _Hash(),
    _Pred                                            = _Pred(),
    _Allocator = _Allocator()) -> unordered_multimap<remove_const_t<_Key>, _Tp, _Hash, _Pred, _Allocator>;

template <class _InputIterator,
          class _Allocator,
          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
    -> unordered_multimap<__iter_key_type<_InputIterator>,
                          __iter_mapped_type<_InputIterator>,
                          hash<__iter_key_type<_InputIterator>>,
                          equal_to<__iter_key_type<_InputIterator>>,
                          _Allocator>;

template <class _InputIterator,
          class _Allocator,
          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(_InputIterator, _InputIterator, _Allocator)
    -> unordered_multimap<__iter_key_type<_InputIterator>,
                          __iter_mapped_type<_InputIterator>,
                          hash<__iter_key_type<_InputIterator>>,
                          equal_to<__iter_key_type<_InputIterator>>,
                          _Allocator>;

template <class _InputIterator,
          class _Hash,
          class _Allocator,
          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
    -> unordered_multimap<__iter_key_type<_InputIterator>,
                          __iter_mapped_type<_InputIterator>,
                          _Hash,
                          equal_to<__iter_key_type<_InputIterator>>,
                          _Allocator>;

#    if _LIBCPP_STD_VER >= 23

template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Allocator)
    -> unordered_multimap<__range_key_type<_Range>,
                          __range_mapped_type<_Range>,
                          hash<__range_key_type<_Range>>,
                          equal_to<__range_key_type<_Range>>,
                          _Allocator>;

template <ranges::input_range _Range, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(from_range_t, _Range&&, _Allocator)
    -> unordered_multimap<__range_key_type<_Range>,
                          __range_mapped_type<_Range>,
                          hash<__range_key_type<_Range>>,
                          equal_to<__range_key_type<_Range>>,
                          _Allocator>;

template <ranges::input_range _Range,
          class _Hash,
          class _Allocator,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(from_range_t, _Range&&, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
    -> unordered_multimap<__range_key_type<_Range>,
                          __range_mapped_type<_Range>,
                          _Hash,
                          equal_to<__range_key_type<_Range>>,
                          _Allocator>;

#    endif

template <class _Key, class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Allocator)
    -> unordered_multimap<remove_const_t<_Key>,
                          _Tp,
                          hash<remove_const_t<_Key>>,
                          equal_to<remove_const_t<_Key>>,
                          _Allocator>;

template <class _Key, class _Tp, class _Allocator, class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)
    -> unordered_multimap<remove_const_t<_Key>,
                          _Tp,
                          hash<remove_const_t<_Key>>,
                          equal_to<remove_const_t<_Key>>,
                          _Allocator>;

template <class _Key,
          class _Tp,
          class _Hash,
          class _Allocator,
          class = enable_if_t<!__is_allocator<_Hash>::value>,
          class = enable_if_t<!is_integral<_Hash>::value>,
          class = enable_if_t<__is_allocator<_Allocator>::value>>
unordered_multimap(
    initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
    -> unordered_multimap<remove_const_t<_Key>, _Tp, _Hash, equal_to<remove_const_t<_Key>>, _Allocator>;
#  endif

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
    size_type __n, const hasher& __hf, const key_equal& __eql)
    : __table_(__hf, __eql) {
  __table_.__rehash_multi(__n);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
    size_type __n, const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
  __table_.__rehash_multi(__n);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
template <class _InputIterator>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(_InputIterator __first, _InputIterator __last) {
  insert(__first, __last);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
template <class _InputIterator>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
    _InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf, const key_equal& __eql)
    : __table_(__hf, __eql) {
  __table_.__rehash_multi(__n);
  insert(__first, __last);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
template <class _InputIterator>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
    _InputIterator __first,
    _InputIterator __last,
    size_type __n,
    const hasher& __hf,
    const key_equal& __eql,
    const allocator_type& __a)
    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
  __table_.__rehash_multi(__n);
  insert(__first, __last);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(const allocator_type& __a)
    : __table_(typename __table::allocator_type(__a)) {}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(const unordered_multimap& __u)
    : __table_(__u.__table_) {
  __table_.__rehash_multi(__u.bucket_count());
  insert(__u.begin(), __u.end());
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
    const unordered_multimap& __u, const allocator_type& __a)
    : __table_(__u.__table_, typename __table::allocator_type(__a)) {
  __table_.__rehash_multi(__u.bucket_count());
  insert(__u.begin(), __u.end());
}

#  ifndef _LIBCPP_CXX03_LANG

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(unordered_multimap&& __u)
    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
    : __table_(std::move(__u.__table_)) {}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
    unordered_multimap&& __u, const allocator_type& __a)
    : __table_(std::move(__u.__table_), typename __table::allocator_type(__a)) {
  if (__a != __u.get_allocator()) {
    iterator __i = __u.begin();
    while (__u.size() != 0) {
      __table_.__insert_multi(__u.__table_.remove((__i++).__i_)->__get_value().__move());
    }
  }
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(initializer_list<value_type> __il) {
  insert(__il.begin(), __il.end());
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
    initializer_list<value_type> __il, size_type __n, const hasher& __hf, const key_equal& __eql)
    : __table_(__hf, __eql) {
  __table_.__rehash_multi(__n);
  insert(__il.begin(), __il.end());
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
    initializer_list<value_type> __il,
    size_type __n,
    const hasher& __hf,
    const key_equal& __eql,
    const allocator_type& __a)
    : __table_(__hf, __eql, typename __table::allocator_type(__a)) {
  __table_.__rehash_multi(__n);
  insert(__il.begin(), __il.end());
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>&
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(unordered_multimap&& __u)
    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value) {
  __table_ = std::move(__u.__table_);
  return *this;
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>&
unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(initializer_list<value_type> __il) {
  __table_.__assign_multi(__il.begin(), __il.end());
  return *this;
}

#  endif // _LIBCPP_CXX03_LANG

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
template <class _InputIterator>
inline void unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::insert(_InputIterator __first, _InputIterator __last) {
  for (; __first != __last; ++__first)
    __table_.__insert_multi(*__first);
}

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline _LIBCPP_HIDE_FROM_ABI void
swap(unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x, unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
  __x.swap(__y);
}

#  if _LIBCPP_STD_VER >= 20
template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc, class _Predicate>
inline _LIBCPP_HIDE_FROM_ABI typename unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::size_type
erase_if(unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __c, _Predicate __pred) {
  return std::__libcpp_erase_if_container(__c, __pred);
}
#  endif

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
_LIBCPP_HIDE_FROM_ABI bool operator==(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
                                      const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y) {
  if (__x.size() != __y.size())
    return false;
  typedef typename unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::const_iterator const_iterator;
  typedef pair<const_iterator, const_iterator> _EqRng;
  for (const_iterator __i = __x.begin(), __ex = __x.end(); __i != __ex;) {
    _EqRng __xeq = __x.equal_range(__i->first);
    _EqRng __yeq = __y.equal_range(__i->first);
    if (std::distance(__xeq.first, __xeq.second) != std::distance(__yeq.first, __yeq.second) ||
        !std::is_permutation(__xeq.first, __xeq.second, __yeq.first))
      return false;
    __i = __xeq.second;
  }
  return true;
}

#  if _LIBCPP_STD_VER <= 17

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
                                             const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y) {
  return !(__x == __y);
}

#  endif

template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
struct __container_traits<unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc> > {
  // http://eel.is/c++draft/unord.req.except#2
  //  For unordered associative containers, if an exception is thrown by any operation
  //  other than the container's hash function from within an insert or emplace function
  //  inserting a single element, the insertion has no effect.
  static _LIBCPP_CONSTEXPR const bool __emplacement_has_strong_exception_safety_guarantee =
      __is_nothrow_invocable_v<_Hash, const _Key&>;
};

_LIBCPP_END_NAMESPACE_STD

#  if _LIBCPP_STD_VER >= 17
_LIBCPP_BEGIN_NAMESPACE_STD
namespace pmr {
template <class _KeyT, class _ValueT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
using unordered_map _LIBCPP_AVAILABILITY_PMR =
    std::unordered_map<_KeyT, _ValueT, _HashT, _PredT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;

template <class _KeyT, class _ValueT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
using unordered_multimap _LIBCPP_AVAILABILITY_PMR =
    std::unordered_multimap<_KeyT, _ValueT, _HashT, _PredT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;
} // namespace pmr
_LIBCPP_END_NAMESPACE_STD
#  endif

_LIBCPP_POP_MACROS

#  if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
#    include <algorithm>
#    include <bit>
#    include <cmath>
#    include <concepts>
#    include <cstdlib>
#    include <iterator>
#    include <type_traits>
#  endif
#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)

#endif // _LIBCPP_UNORDERED_MAP