.. code:: cpp

    size_type count( const key_type& key );

**Returns**: the number of elements equivalent to ``key``.

.. code:: cpp

    template <typename K>
    size_type count( const K& key );

**Returns**: the number of elements that are equivalent to ``key``.

This overload only participates in overload resolution if qualified-id
``key_compare::is_transparent`` is valid and denotes a type.

.. code:: cpp

    iterator find( const key_type& key );

    const_iterator find( const key_type& key ) const;

**Returns**: an iterator to the element equivalent to ``key``, or ``end()``
if no such element exists.

.. code:: cpp

    template <typename K>
    iterator find( const K& key );

    template <typename K>
    const_iterator find( const K& key ) const;

**Returns**: an iterator to the element that is equivalent to ``key``, or ``end()`` if no such element exists.

These overloads only participates in overload resolution if qualified-id
``key_compare::is_transparent`` is valid and denotes a type.

.. code:: cpp

    bool contains( const key_type& key ) const;

**Returns**: ``true`` if an element equivalent to ``key`` exists
in the container; ``false``, otherwise.

.. code:: cpp

    template <typename K>
    bool contains( const K& key ) const;

**Returns**: ``true`` if an element equivalent to ``key`` exists in the container; ``false``, otherwise.

This overload only participates in overload resolution if qualified-id
``key_compare::is_transparent`` is valid and denotes a type.

.. code:: cpp

    iterator lower_bound( const key_type& key );

    const_iterator lower_bound( const key_type& key ) const;

**Returns**: an iterator to the first element in the container
that is `not less` than ``key``.

.. code:: cpp

    template <typename K>
    iterator lower_bound( const K& key )

    template <typename K>
    const_iterator lower_bound( const K& key ) const

**Returns**: an iterator to the first element in the container that is `not less` than ``key``.

These overloads only participate in overload resolution if qualified-id
``key_compare::is_transparent`` is valid and denotes a type.

.. code:: cpp

  iterator upper_bound( const key_type& key );

  const_iterator upper_bound( const key_type& key ) const;

**Returns**: an iterator to the first element in the container
that compares `greater` than ``key``.

.. code:: cpp

  template <typename K>
  iterator upper_bound( const K& key );

  template <typename K>
  const_iterator upper_bound( const K& key ) const;

**Returns**: an iterator to the first element in the container
that compares ``greater`` than ``key``.

These overloads only participate in overload resolution if qualified-id
``key_compare::is_transparent`` is valid and denotes a type.

.. code:: cpp

    std::pair<iterator, iterator> equal_range( const key_type& key );

    std::pair<const_iterator, const_iterator> equal_range( const key_type& key ) const;

**Returns**: if an element equivalent to ``key`` exists, a pair of iterators
``{f, l}``, where ``f`` is an iterator to this element, ``l`` is ``std::next(f)``.
Otherwise, ``{end(), end()}``.

.. code:: cpp

    template <typename K>
    std::pair<iterator, iterator> equal_range( const K& key )

    template <typename K>
    std::pair<const_iterator, const_iterator> equal_range( const K& key )

**Returns**: if an element equivalent to ``key`` exists, a pair of iterators ``{f, l}``, where ``f`` is an iterator to this element,
``l`` is ``std::next(f)``. Otherwise, ``{end(), end()}``.

These overloads only participate in overload resolution if qualified-id
``key_compare::is_transparent`` is valid and denotes a type.