#include <initializer_list>

namespace std {
  // クラステンプレート unordered_map
  template <class Key,
            class T,
            class Hash = std::hash<Key>,
            class Pred = std::equal_to<Key>,
            class Allocator = std::allocator<std::pair<const Key, T> > >
    class unordered_map;

  // クラステンプレート unordered_multimap
  template <class Key,
            class T,
            class Hash = std::hash<Key>,
            class Pred = std::equal_to<Key>,
            class Allocator = std::allocator<std::pair<const Key, T> > >
    class unordered_multimap;

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

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

  template <class Key, class T, class Hash, class Pred, class Allocator>
    bool operator==(const unordered_map<Key, T, Hash, Pred, Allocator>& a,
                    const unordered_map<Key, T, Hash, Pred, Allocator>& b);
  template <class Key, class T, class Hash, class Pred, class Allocator>
    bool operator!=(const unordered_map<Key, T, Hash, Pred, Allocator>& a,
                    const unordered_map<Key, T, Hash, Pred, Allocator>& b);

  template <class Key, class T, class Hash, class Pred, class Allocator>
    bool operator==(const unordered_multimap<Key, T, Hash, Pred, Allocator>& a,
                    const unordered_multimap<Key, T, Hash, Pred, Allocator>& b);
  template <class Key, class Hash, class Pred, class Allocator>
    bool operator!=(const unordered_multimap<Key, T, Hash, Pred, Allocator>& a,
                    const unordered_multimap<Key, T, Hash, Pred, Allocator>& b);
}