Hu Chunming / sip_server

//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2013. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/container for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_CONTAINER_FLAT_SET_HPP
#define BOOST_CONTAINER_FLAT_SET_HPP

#ifndef BOOST_CONFIG_HPP
#  include <boost/config.hpp>
#endif

#if defined(BOOST_HAS_PRAGMA_ONCE)
#  pragma once
#endif

#include <boost/container/detail/config_begin.hpp>
#include <boost/container/detail/workaround.hpp>

// container
#include <boost/container/allocator_traits.hpp>
#include <boost/container/container_fwd.hpp>
#include <boost/container/new_allocator.hpp> //new_allocator
// container/detail
#include <boost/container/detail/flat_tree.hpp>
#include <boost/container/detail/mpl.hpp>
// move
#include <boost/move/traits.hpp>
#include <boost/move/utility_core.hpp>
// move/detail
#if defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
#include <boost/move/detail/fwd_macros.hpp>
#endif
#include <boost/move/detail/move_helpers.hpp>
// intrusive/detail
#include <boost/intrusive/detail/minimal_pair_header.hpp>      //pair
#include <boost/intrusive/detail/minimal_less_equal_header.hpp>//less, equal
// std
#if !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST)
#include <initializer_list>
#endif

namespace boost {
namespace container {

#if !defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
template <class Key, class Compare, class AllocatorOrContainer>
class flat_multiset;
#endif

//! flat_set is a Sorted Associative Container that stores objects of type Key.
//! It is also a Unique Associative Container, meaning that no two elements are the same.
//!
//! flat_set is similar to std::set but it's implemented by as an ordered sequence container.
//! The underlying sequence container is by default <i>vector</i> but it can also work
//! user-provided vector-like SequenceContainers (like <i>static_vector</i> or <i>small_vector</i>).
//!
//! Using vector-like sequence containers means that inserting a new element into a flat_set might invalidate
//! previous iterators and references (unless that sequence container is <i>stable_vector</i> or a similar
//! container that offers stable pointers and references). Similarly, erasing an element might invalidate
//! iterators and references pointing to elements that come after (their keys are bigger) the erased element.
//!
//! This container provides random-access iterators.
//!
//! \tparam Key is the type to be inserted in the set, which is also the key_type
//! \tparam Compare is the comparison functor used to order keys
//! \tparam AllocatorOrContainer is either:
//!   - The allocator to allocate <code>value_type</code>s (e.g. <i>allocator< std::pair<Key, T> > </i>).
//!     (in this case <i>sequence_type</i> will be vector<value_type, AllocatorOrContainer>)
//!   - The SequenceContainer to be used as the underlying <i>sequence_type</i>. It must be a vector-like
//!     sequence container with random-access iterators.
#ifdef BOOST_CONTAINER_DOXYGEN_INVOKED
template <class Key, class Compare = std::less<Key>, class AllocatorOrContainer = new_allocator<Key> >
#else
template <class Key, class Compare, class AllocatorOrContainer>
#endif
class flat_set
   ///@cond
   : public dtl::flat_tree<Key, dtl::identity<Key>, Compare, AllocatorOrContainer>
   ///@endcond
{
   #ifndef BOOST_CONTAINER_DOXYGEN_INVOKED
   private:
   BOOST_COPYABLE_AND_MOVABLE(flat_set)
   typedef dtl::flat_tree<Key, dtl::identity<Key>, Compare, AllocatorOrContainer> tree_t;

   public:
   tree_t &tree()
   {  return *this;  }

   const tree_t &tree() const
   {  return *this;  }

   #endif   //#ifndef BOOST_CONTAINER_DOXYGEN_INVOKED

   public:
   //////////////////////////////////////////////
   //
   //                    types
   //
   //////////////////////////////////////////////
   typedef Key                                                                      key_type;
   typedef Compare                                                                  key_compare;
   typedef Key                                                                      value_type;
   typedef typename BOOST_CONTAINER_IMPDEF(tree_t::sequence_type)                   sequence_type;
   typedef typename sequence_type::allocator_type                                   allocator_type;
   typedef ::boost::container::allocator_traits<allocator_type>                     allocator_traits_type;
   typedef typename sequence_type::pointer                                          pointer;
   typedef typename sequence_type::const_pointer                                    const_pointer;
   typedef typename sequence_type::reference                                        reference;
   typedef typename sequence_type::const_reference                                  const_reference;
   typedef typename sequence_type::size_type                                        size_type;
   typedef typename sequence_type::difference_type                                  difference_type;
   typedef typename BOOST_CONTAINER_IMPDEF(tree_t::stored_allocator_type)           stored_allocator_type;
   typedef typename BOOST_CONTAINER_IMPDEF(tree_t::value_compare)                   value_compare;

   typedef typename sequence_type::iterator                                         iterator;
   typedef typename sequence_type::const_iterator                                   const_iterator;
   typedef typename sequence_type::reverse_iterator                                 reverse_iterator;
   typedef typename sequence_type::const_reverse_iterator                           const_reverse_iterator;

   public:
   //////////////////////////////////////////////
   //
   //          construct/copy/destroy
   //
   //////////////////////////////////////////////

   //! <b>Effects</b>: Default constructs an empty container.
   //!
   //! <b>Complexity</b>: Constant.
   BOOST_CONTAINER_FORCEINLINE
   flat_set() BOOST_NOEXCEPT_IF(dtl::is_nothrow_default_constructible<AllocatorOrContainer>::value &&
                                dtl::is_nothrow_default_constructible<Compare>::value)
      : tree_t()
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified
   //! comparison object.
   //!
   //! <b>Complexity</b>: Constant.
   BOOST_CONTAINER_FORCEINLINE
   explicit flat_set(const Compare& comp)
      : tree_t(comp)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified allocator.
   //!
   //! <b>Complexity</b>: Constant.
   BOOST_CONTAINER_FORCEINLINE
   explicit flat_set(const allocator_type& a)
      : tree_t(a)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified
   //! comparison object and allocator.
   //!
   //! <b>Complexity</b>: Constant.
   BOOST_CONTAINER_FORCEINLINE
   flat_set(const Compare& comp, const allocator_type& a)
      : tree_t(comp, a)
   {}

   //! <b>Effects</b>: Constructs an empty container and
   //! inserts elements from the range [first ,last ).
   //!
   //! <b>Complexity</b>: Linear in N if the range [first ,last ) is already sorted using
   //! comp and otherwise N logN, where N is last - first.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE
   flat_set(InputIterator first, InputIterator last)
      : tree_t(true, first, last)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified
   //! allocator, and inserts elements from the range [first ,last ).
   //!
   //! <b>Complexity</b>: Linear in N if the range [first ,last ) is already sorted using
   //! comp and otherwise N logN, where N is last - first.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE
   flat_set(InputIterator first, InputIterator last, const allocator_type& a)
      : tree_t(true, first, last, a)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! inserts elements from the range [first ,last ).
   //!
   //! <b>Complexity</b>: Linear in N if the range [first ,last ) is already sorted using
   //! comp and otherwise N logN, where N is last - first.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE
   flat_set(InputIterator first, InputIterator last, const Compare& comp)
      : tree_t(true, first, last, comp)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! allocator, and inserts elements from the range [first ,last ).
   //!
   //! <b>Complexity</b>: Linear in N if the range [first ,last ) is already sorted using
   //! comp and otherwise N logN, where N is last - first.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE
   flat_set(InputIterator first, InputIterator last, const Compare& comp, const allocator_type& a)
      : tree_t(true, first, last, comp, a)
   {}

   //! <b>Effects</b>: Constructs an empty container and
   //! inserts elements from the ordered unique range [first ,last). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [first ,last) must be ordered according to the predicate and must be
   //! unique values.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE
   flat_set(ordered_unique_range_t, InputIterator first, InputIterator last)
      : tree_t(ordered_unique_range, first, last)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! inserts elements from the ordered unique range [first ,last). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [first ,last) must be ordered according to the predicate and must be
   //! unique values.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE
   flat_set(ordered_unique_range_t, InputIterator first, InputIterator last, const Compare& comp)
      : tree_t(ordered_unique_range, first, last, comp)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! allocator, and inserts elements from the ordered unique range [first ,last). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [first ,last) must be ordered according to the predicate and must be
   //! unique values.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE
   flat_set(ordered_unique_range_t, InputIterator first, InputIterator last, const Compare& comp, const allocator_type& a)
      : tree_t(ordered_unique_range, first, last, comp, a)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified allocator and
   //! inserts elements from the ordered unique range [first ,last). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [first ,last) must be ordered according to the predicate and must be
   //! unique values.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE
      flat_set(ordered_unique_range_t, InputIterator first, InputIterator last, const allocator_type& a)
      : tree_t(ordered_unique_range, first, last, Compare(), a)
   {}

#if !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST)
   //! <b>Effects</b>: Constructs an empty container and
   //! inserts elements from the range [il.begin(), il.end()).
   //!
   //! <b>Complexity</b>: Linear in N if the range [il.begin(), il.end()) is already sorted using
   //! comp and otherwise N logN, where N is il.begin() - il.end().
   BOOST_CONTAINER_FORCEINLINE flat_set(std::initializer_list<value_type> il)
      : tree_t(true, il.begin(), il.end())
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified
   //! allocator, and inserts elements from the range [il.begin(), il.end()).
   //!
   //! <b>Complexity</b>: Linear in N if the range [il.begin(), il.end()) is already sorted using
   //! comp and otherwise N logN, where N is il.begin() - il.end().
   BOOST_CONTAINER_FORCEINLINE flat_set(std::initializer_list<value_type> il, const allocator_type& a)
      : tree_t(true, il.begin(), il.end(), a)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! inserts elements from the range [il.begin(), il.end()).
   //!
   //! <b>Complexity</b>: Linear in N if the range [il.begin(), il.end()) is already sorted using
   //! comp and otherwise N logN, where N is il.begin() - il.end().
   BOOST_CONTAINER_FORCEINLINE flat_set(std::initializer_list<value_type> il, const Compare& comp)
      : tree_t(true, il.begin(), il.end(), comp)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! allocator, and inserts elements from the range [il.begin(), il.end()).
   //!
   //! <b>Complexity</b>: Linear in N if the range [il.begin(), il.end()) is already sorted using
   //! comp and otherwise N logN, where N is il.begin() - il.end().
   BOOST_CONTAINER_FORCEINLINE flat_set(std::initializer_list<value_type> il, const Compare& comp, const allocator_type& a)
      : tree_t(true, il.begin(), il.end(), comp, a)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! inserts elements from the ordered unique range [il.begin(), il.end()). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [il.begin(), il.end()) must be ordered according to the predicate and must be
   //! unique values.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   BOOST_CONTAINER_FORCEINLINE flat_set(ordered_unique_range_t, std::initializer_list<value_type> il)
      : tree_t(ordered_unique_range, il.begin(), il.end())
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! inserts elements from the ordered unique range [il.begin(), il.end()). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [il.begin(), il.end()) must be ordered according to the predicate and must be
   //! unique values.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   BOOST_CONTAINER_FORCEINLINE flat_set(ordered_unique_range_t, std::initializer_list<value_type> il, const Compare& comp)
      : tree_t(ordered_unique_range, il.begin(), il.end(), comp)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! allocator, and inserts elements from the ordered unique range [il.begin(), il.end()). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [il.begin(), il.end()) must be ordered according to the predicate and must be
   //! unique values.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   BOOST_CONTAINER_FORCEINLINE flat_set(ordered_unique_range_t, std::initializer_list<value_type> il, const Compare& comp, const allocator_type& a)
      : tree_t(ordered_unique_range, il.begin(), il.end(), comp, a)
   {}
#endif

   //! <b>Effects</b>: Copy constructs the container.
   //!
   //! <b>Complexity</b>: Linear in x.size().
   BOOST_CONTAINER_FORCEINLINE flat_set(const flat_set& x)
      : tree_t(static_cast<const tree_t&>(x))
   {}

   //! <b>Effects</b>: Move constructs thecontainer. Constructs *this using x's resources.
   //!
   //! <b>Complexity</b>: Constant.
   //!
   //! <b>Postcondition</b>: x is emptied.
   BOOST_CONTAINER_FORCEINLINE flat_set(BOOST_RV_REF(flat_set) x)
      BOOST_NOEXCEPT_IF(boost::container::dtl::is_nothrow_move_constructible<Compare>::value)
      : tree_t(BOOST_MOVE_BASE(tree_t, x))
   {}

   //! <b>Effects</b>: Copy constructs a container using the specified allocator.
   //!
   //! <b>Complexity</b>: Linear in x.size().
   BOOST_CONTAINER_FORCEINLINE flat_set(const flat_set& x, const allocator_type &a)
      : tree_t(static_cast<const tree_t&>(x), a)
   {}

   //! <b>Effects</b>: Move constructs a container using the specified allocator.
   //!                 Constructs *this using x's resources.
   //!
   //! <b>Complexity</b>: Constant if a == x.get_allocator(), linear otherwise
   BOOST_CONTAINER_FORCEINLINE flat_set(BOOST_RV_REF(flat_set) x, const allocator_type &a)
      : tree_t(BOOST_MOVE_BASE(tree_t, x), a)
   {}

   //! <b>Effects</b>: Makes *this a copy of x.
   //!
   //! <b>Complexity</b>: Linear in x.size().
   BOOST_CONTAINER_FORCEINLINE flat_set& operator=(BOOST_COPY_ASSIGN_REF(flat_set) x)
   {  return static_cast<flat_set&>(this->tree_t::operator=(static_cast<const tree_t&>(x)));  }

   //! <b>Throws</b>: If allocator_traits_type::propagate_on_container_move_assignment
   //!   is false and (allocation throws or value_type's move constructor throws)
   //!
   //! <b>Complexity</b>: Constant if allocator_traits_type::
   //!   propagate_on_container_move_assignment is true or
   //!   this->get>allocator() == x.get_allocator(). Linear otherwise.
   BOOST_CONTAINER_FORCEINLINE flat_set& operator=(BOOST_RV_REF(flat_set) x)
      BOOST_NOEXCEPT_IF( (allocator_traits_type::propagate_on_container_move_assignment::value ||
                          allocator_traits_type::is_always_equal::value) &&
                           boost::container::dtl::is_nothrow_move_assignable<Compare>::value)
   {  return static_cast<flat_set&>(this->tree_t::operator=(BOOST_MOVE_BASE(tree_t, x)));  }

#if !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST)
   //! <b>Effects</b>: Copy all elements from il to *this.
   //!
   //! <b>Complexity</b>: Linear in il.size().
   flat_set& operator=(std::initializer_list<value_type> il)
   {
       this->clear();
       this->insert(il.begin(), il.end());
       return *this;
   }
#endif

   #ifdef BOOST_CONTAINER_DOXYGEN_INVOKED
   //! <b>Effects</b>: Returns a copy of the allocator that
   //!   was passed to the object's constructor.
   //!
   //! <b>Complexity</b>: Constant.
   allocator_type get_allocator() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a reference to the internal allocator.
   //!
   //! <b>Throws</b>: Nothing
   //!
   //! <b>Complexity</b>: Constant.
   //!
   //! <b>Note</b>: Non-standard extension.
   stored_allocator_type &get_stored_allocator() BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a reference to the internal allocator.
   //!
   //! <b>Throws</b>: Nothing
   //!
   //! <b>Complexity</b>: Constant.
   //!
   //! <b>Note</b>: Non-standard extension.
   const stored_allocator_type &get_stored_allocator() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns an iterator to the first element contained in the container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   iterator begin() BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a const_iterator to the first element contained in the container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   const_iterator begin() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns an iterator to the end of the container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   iterator end() BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a const_iterator to the end of the container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   const_iterator end() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a reverse_iterator pointing to the beginning
   //! of the reversed container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   reverse_iterator rbegin() BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the beginning
   //! of the reversed container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   const_reverse_iterator rbegin() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a reverse_iterator pointing to the end
   //! of the reversed container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   reverse_iterator rend() BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the end
   //! of the reversed container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   const_reverse_iterator rend() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a const_iterator to the first element contained in the container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   const_iterator cbegin() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a const_iterator to the end of the container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   const_iterator cend() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the beginning
   //! of the reversed container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   const_reverse_iterator crbegin() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns a const_reverse_iterator pointing to the end
   //! of the reversed container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   const_reverse_iterator crend() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns true if the container contains no elements.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   bool empty() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns the number of the elements contained in the container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   size_type size() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns the largest possible size of the container.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   size_type max_size() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Number of elements for which memory has been allocated.
   //!   capacity() is always greater than or equal to size().
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   size_type capacity() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: If n is less than or equal to capacity(), or the
   //!   underlying container has no `reserve` member, this call has no
   //!   effect. Otherwise, it is a request for allocation of additional memory.
   //!   If the request is successful, then capacity() is greater than or equal to
   //!   n; otherwise, capacity() is unchanged. In either case, size() is unchanged.
   //!
   //! <b>Throws</b>: If memory allocation allocation throws or T's copy constructor throws.
   //!
   //! <b>Note</b>: If capacity() is less than "cnt", iterators and references to
   //!   to values might be invalidated.
   void reserve(size_type cnt);

   //! <b>Effects</b>: Tries to deallocate the excess of memory created
   //    with previous allocations. The size of the vector is unchanged
   //!
   //! <b>Throws</b>: If memory allocation throws, or Key's copy constructor throws.
   //!
   //! <b>Complexity</b>: Linear to size().
   void shrink_to_fit();

   #endif   //   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //////////////////////////////////////////////
   //
   //                modifiers
   //
   //////////////////////////////////////////////

   #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) || defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //! <b>Effects</b>: Inserts an object x of type Key constructed with
   //!   std::forward<Args>(args)... if and only if there is no element in the container
   //!   with key equivalent to the key of x.
   //!
   //! <b>Returns</b>: The bool component of the returned pair is true if and only
   //!   if the insertion takes place, and the iterator component of the pair
   //!   points to the element with key equivalent to the key of x.
   //!
   //! <b>Complexity</b>: Logarithmic search time plus linear insertion
   //!   to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   template <class... Args>
   BOOST_CONTAINER_FORCEINLINE std::pair<iterator,bool> emplace(BOOST_FWD_REF(Args)... args)
   {  return this->tree_t::emplace_unique(boost::forward<Args>(args)...); }

   //! <b>Effects</b>: Inserts an object of type Key constructed with
   //!   std::forward<Args>(args)... in the container if and only if there is
   //!   no element in the container with key equivalent to the key of x.
   //!   p is a hint pointing to where the insert should start to search.
   //!
   //! <b>Returns</b>: An iterator pointing to the element with key equivalent
   //!   to the key of x.
   //!
   //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
   //!   right before p) plus insertion linear to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   template <class... Args>
   BOOST_CONTAINER_FORCEINLINE iterator emplace_hint(const_iterator p, BOOST_FWD_REF(Args)... args)
   {  return this->tree_t::emplace_hint_unique(p, boost::forward<Args>(args)...); }

   #else // !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

   #define BOOST_CONTAINER_FLAT_SET_EMPLACE_CODE(N) \
   BOOST_MOVE_TMPL_LT##N BOOST_MOVE_CLASS##N BOOST_MOVE_GT##N \
   BOOST_CONTAINER_FORCEINLINE std::pair<iterator,bool> emplace(BOOST_MOVE_UREF##N)\
   {  return this->tree_t::emplace_unique(BOOST_MOVE_FWD##N);  }\
   \
   BOOST_MOVE_TMPL_LT##N BOOST_MOVE_CLASS##N BOOST_MOVE_GT##N \
   BOOST_CONTAINER_FORCEINLINE iterator emplace_hint(const_iterator hint BOOST_MOVE_I##N BOOST_MOVE_UREF##N)\
   {  return this->tree_t::emplace_hint_unique(hint BOOST_MOVE_I##N BOOST_MOVE_FWD##N); }\
   //
   BOOST_MOVE_ITERATE_0TO9(BOOST_CONTAINER_FLAT_SET_EMPLACE_CODE)
   #undef BOOST_CONTAINER_FLAT_SET_EMPLACE_CODE

   #endif   // !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
   //! <b>Effects</b>: Inserts x if and only if there is no element in the container
   //!   with key equivalent to the key of x.
   //!
   //! <b>Returns</b>: The bool component of the returned pair is true if and only
   //!   if the insertion takes place, and the iterator component of the pair
   //!   points to the element with key equivalent to the key of x.
   //!
   //! <b>Complexity</b>: Logarithmic search time plus linear insertion
   //!   to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   std::pair<iterator, bool> insert(const value_type &x);

   //! <b>Effects</b>: Inserts a new value_type move constructed from the pair if and
   //! only if there is no element in the container with key equivalent to the key of x.
   //!
   //! <b>Returns</b>: The bool component of the returned pair is true if and only
   //!   if the insertion takes place, and the iterator component of the pair
   //!   points to the element with key equivalent to the key of x.
   //!
   //! <b>Complexity</b>: Logarithmic search time plus linear insertion
   //!   to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   std::pair<iterator, bool> insert(value_type &&x);
   #else
   private:
   typedef std::pair<iterator, bool> insert_return_pair;
   public:
   BOOST_MOVE_CONVERSION_AWARE_CATCH(insert, value_type, insert_return_pair, this->tree_t::insert_unique)
   #endif

   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
   //! <b>Effects</b>: Inserts a copy of x in the container if and only if there is
   //!   no element in the container with key equivalent to the key of x.
   //!   p is a hint pointing to where the insert should start to search.
   //!
   //! <b>Returns</b>: An iterator pointing to the element with key equivalent
   //!   to the key of x.
   //!
   //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
   //!   right before p) plus insertion linear to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   iterator insert(const_iterator p, const value_type &x);

   //! <b>Effects</b>: Inserts an element move constructed from x in the container.
   //!   p is a hint pointing to where the insert should start to search.
   //!
   //! <b>Returns</b>: An iterator pointing to the element with key equivalent to the key of x.
   //!
   //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
   //!   right before p) plus insertion linear to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   iterator insert(const_iterator p, value_type &&x);
   #else
   BOOST_MOVE_CONVERSION_AWARE_CATCH_1ARG(insert, value_type, iterator, this->tree_t::insert_unique, const_iterator, const_iterator)
   #endif

   //! <b>Requires</b>: first, last are not iterators into *this.
   //!
   //! <b>Effects</b>: inserts each element from the range [first,last) if and only
   //!   if there is no element with key equivalent to the key of that element.
   //!
   //! <b>Complexity</b>: N log(N).
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE void insert(InputIterator first, InputIterator last)
      {  this->tree_t::insert_unique(first, last);  }

   //! <b>Requires</b>: first, last are not iterators into *this and
   //! must be ordered according to the predicate and must be
   //! unique values.
   //!
   //! <b>Effects</b>: inserts each element from the range [first,last) .This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Complexity</b>: Linear.
   //!
   //! <b>Note</b>: Non-standard extension. If an element is inserted it might invalidate elements.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE void insert(ordered_unique_range_t, InputIterator first, InputIterator last)
      {  this->tree_t::insert_unique(ordered_unique_range, first, last);  }

#if !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST)
   //! <b>Effects</b>: inserts each element from the range [il.begin(), il.end()) if and only
   //!   if there is no element with key equivalent to the key of that element.
   //!
   //! <b>Complexity</b>: N log(N).
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   BOOST_CONTAINER_FORCEINLINE void insert(std::initializer_list<value_type> il)
   {  this->tree_t::insert_unique(il.begin(), il.end()); }

   //! <b>Requires</b>: Range [il.begin(), il.end()) must be ordered according to the predicate
   //! and must be unique values.
   //!
   //! <b>Effects</b>: inserts each element from the range [il.begin(), il.end()) .This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Complexity</b>: Linear.
   //!
   //! <b>Note</b>: Non-standard extension. If an element is inserted it might invalidate elements.
   BOOST_CONTAINER_FORCEINLINE void insert(ordered_unique_range_t, std::initializer_list<value_type> il)
   {  this->tree_t::insert_unique(ordered_unique_range, il.begin(), il.end()); }
#endif

   //! @copydoc ::boost::container::flat_map::merge(flat_map<Key, T, C2, AllocatorOrContainer>&)
   template<class C2>
   BOOST_CONTAINER_FORCEINLINE void merge(flat_set<Key, C2, AllocatorOrContainer>& source)
   {  this->tree_t::merge_unique(source.tree());   }

   //! @copydoc ::boost::container::flat_set::merge(flat_set<Key, C2, AllocatorOrContainer>&)
   template<class C2>
   BOOST_CONTAINER_FORCEINLINE void merge(BOOST_RV_REF_BEG flat_set<Key, C2, AllocatorOrContainer> BOOST_RV_REF_END source)
   {  return this->merge(static_cast<flat_set<Key, C2, AllocatorOrContainer>&>(source));   }

   //! @copydoc ::boost::container::flat_map::merge(flat_multimap<Key, T, C2, AllocatorOrContainer>&)
   template<class C2>
   BOOST_CONTAINER_FORCEINLINE void merge(flat_multiset<Key, C2, AllocatorOrContainer>& source)
   {  this->tree_t::merge_unique(source.tree());   }

   //! @copydoc ::boost::container::flat_set::merge(flat_multiset<Key, C2, AllocatorOrContainer>&)
   template<class C2>
   BOOST_CONTAINER_FORCEINLINE void merge(BOOST_RV_REF_BEG flat_multiset<Key, C2, AllocatorOrContainer> BOOST_RV_REF_END source)
   {  return this->merge(static_cast<flat_multiset<Key, C2, AllocatorOrContainer>&>(source));   }

   //! <b>Effects</b>: If present, erases the element in the container with key equivalent to x.
   //!
   //! <b>Returns</b>: Returns the number of erased elements (0/1).
   //!
   //! <b>Complexity</b>: Logarithmic search time plus erasure time
   //!   linear to the elements with bigger keys.
   BOOST_CONTAINER_FORCEINLINE size_type erase(const key_type& x)
   {  return this->tree_t::erase_unique(x);   }

   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //! <b>Effects</b>: Erases the element pointed to by p.
   //!
   //! <b>Returns</b>: Returns an iterator pointing to the element immediately
   //!   following q prior to the element being erased. If no such element exists,
   //!   returns end().
   //!
   //! <b>Complexity</b>: Linear to the elements with keys bigger than p
   //!
   //! <b>Note</b>: Invalidates elements with keys
   //!   not less than the erased element.
   iterator erase(const_iterator p);

   //! <b>Effects</b>: Erases all the elements in the range [first, last).
   //!
   //! <b>Returns</b>: Returns last.
   //!
   //! <b>Complexity</b>: size()*N where N is the distance from first to last.
   //!
   //! <b>Complexity</b>: Logarithmic search time plus erasure time
   //!   linear to the elements with bigger keys.
   iterator erase(const_iterator first, const_iterator last);

   //! <b>Effects</b>: Swaps the contents of *this and x.
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   void swap(flat_set& x)
      BOOST_NOEXCEPT_IF(  allocator_traits_type::is_always_equal::value
                                 && boost::container::dtl::is_nothrow_swappable<Compare>::value );

   //! <b>Effects</b>: erase(begin(),end()).
   //!
   //! <b>Postcondition</b>: size() == 0.
   //!
   //! <b>Complexity</b>: linear in size().
   void clear() BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Effects</b>: Returns the comparison object out
   //!   of which a was constructed.
   //!
   //! <b>Complexity</b>: Constant.
   key_compare key_comp() const;

   //! <b>Effects</b>: Returns an object of value_compare constructed out
   //!   of the comparison object.
   //!
   //! <b>Complexity</b>: Constant.
   value_compare value_comp() const;

   //! <b>Returns</b>: An iterator pointing to an element with the key
   //!   equivalent to x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic.
   iterator find(const key_type& x);

   //! <b>Returns</b>: A const_iterator pointing to an element with the key
   //!   equivalent to x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic.
   const_iterator find(const key_type& x) const;

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Returns</b>: An iterator pointing to an element with the key
   //!   equivalent to x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic.
   template<typename K>
   iterator find(const K& x);

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Returns</b>: A const_iterator pointing to an element with the key
   //!   equivalent to x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic.
   template<typename K>
   const_iterator find(const K& x) const;

   //! <b>Requires</b>: size() >= n.
   //!
   //! <b>Effects</b>: Returns an iterator to the nth element
   //!   from the beginning of the container. Returns end()
   //!   if n == size().
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   //!
   //! <b>Note</b>: Non-standard extension
   iterator nth(size_type n) BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Requires</b>: size() >= n.
   //!
   //! <b>Effects</b>: Returns a const_iterator to the nth element
   //!   from the beginning of the container. Returns end()
   //!   if n == size().
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   //!
   //! <b>Note</b>: Non-standard extension
   const_iterator nth(size_type n) const BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Requires</b>: begin() <= p <= end().
   //!
   //! <b>Effects</b>: Returns the index of the element pointed by p
   //!   and size() if p == end().
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   //!
   //! <b>Note</b>: Non-standard extension
   size_type index_of(iterator p) BOOST_NOEXCEPT_OR_NOTHROW;

   //! <b>Requires</b>: begin() <= p <= end().
   //!
   //! <b>Effects</b>: Returns the index of the element pointed by p
   //!   and size() if p == end().
   //!
   //! <b>Throws</b>: Nothing.
   //!
   //! <b>Complexity</b>: Constant.
   //!
   //! <b>Note</b>: Non-standard extension
   size_type index_of(const_iterator p) const BOOST_NOEXCEPT_OR_NOTHROW;

   #else
   using tree_t::erase;
   #endif   //   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //! <b>Returns</b>: The number of elements with key equivalent to x.
   //!
   //! <b>Complexity</b>: log(size())+count(k)
   BOOST_CONTAINER_FORCEINLINE size_type count(const key_type& x) const
   {  return static_cast<size_type>(this->tree_t::find(x) != this->tree_t::cend());  }

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Returns</b>: The number of elements with key equivalent to x.
   //!
   //! <b>Complexity</b>: log(size())+count(k)
   template<typename K>
   BOOST_CONTAINER_FORCEINLINE size_type count(const K& x) const
      //Don't use find() != end optimization here as transparent comparators with key K might
      //return a different range than key_type (which can only return a single element range)
   {  return this->tree_t::count(x);  }

   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //! <b>Returns</b>: Returns true if there is an element with key
   //!   equivalent to key in the container, otherwise false.
   //!
   //! <b>Complexity</b>: log(size()).
   bool contains(const key_type& x) const;

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Returns</b>: Returns true if there is an element with key
   //!   equivalent to key in the container, otherwise false.
   //!
   //! <b>Complexity</b>: log(size()).
   template<typename K>
   bool contains(const K& x) const;

   //! <b>Returns</b>: An iterator pointing to the first element with key not less
   //!   than x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic
   iterator lower_bound(const key_type& x);

   //! <b>Returns</b>: A const iterator pointing to the first element with key not
   //!   less than x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic
   const_iterator lower_bound(const key_type& x) const;

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Returns</b>: An iterator pointing to the first element with key not less
   //!   than x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic
   template<typename K>
   iterator lower_bound(const K& x);

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Returns</b>: A const iterator pointing to the first element with key not
   //!   less than x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic
   template<typename K>
   const_iterator lower_bound(const K& x) const;

   //! <b>Returns</b>: An iterator pointing to the first element with key greater
   //!   than x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic
   iterator upper_bound(const key_type& x);

   //! <b>Returns</b>: A const iterator pointing to the first element with key 
   //!   greater than x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic
   const_iterator upper_bound(const key_type& x) const;

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Returns</b>: An iterator pointing to the first element with key greater
   //!   than x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic
   template<typename K>
   iterator upper_bound(const K& x);

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Returns</b>: A const iterator pointing to the first element with key
   //!   greater than x, or end() if such an element is not found.
   //!
   //! <b>Complexity</b>: Logarithmic
   template<typename K>
   const_iterator upper_bound(const K& x) const;

   #endif   //   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //! <b>Effects</b>: Equivalent to std::make_pair(this->lower_bound(k), this->upper_bound(k)).
   //!
   //! <b>Complexity</b>: Logarithmic
   BOOST_CONTAINER_FORCEINLINE std::pair<const_iterator, const_iterator> equal_range(const key_type& x) const
   {  return this->tree_t::lower_bound_range(x);  }

   //! <b>Effects</b>: Equivalent to std::make_pair(this->lower_bound(k), this->upper_bound(k)).
   //!
   //! <b>Complexity</b>: Logarithmic
   BOOST_CONTAINER_FORCEINLINE std::pair<iterator,iterator> equal_range(const key_type& x)
   {  return this->tree_t::lower_bound_range(x);  }

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Effects</b>: Equivalent to std::make_pair(this->lower_bound(k), this->upper_bound(k)).
   //!
   //! <b>Complexity</b>: Logarithmic
   template<typename K>
   std::pair<iterator,iterator> equal_range(const K& x)
      //Don't use lower_bound_range optimization here as transparent comparators with key K might
      //return a different range than key_type (which can only return a single element range)
   {  return this->tree_t::equal_range(x);  }

   //! <b>Requires</b>: This overload is available only if
   //! key_compare::is_transparent exists.
   //!
   //! <b>Effects</b>: Equivalent to std::make_pair(this->lower_bound(k), this->upper_bound(k)).
   //!
   //! <b>Complexity</b>: Logarithmic
   template<typename K>
   std::pair<const_iterator,const_iterator> equal_range(const K& x) const
      //Don't use lower_bound_range optimization here as transparent comparators with key K might
      //return a different range than key_type (which can only return a single element range)
   {  return this->tree_t::equal_range(x);  }

   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //! <b>Effects</b>: Returns true if x and y are equal
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator==(const flat_set& x, const flat_set& y);

   //! <b>Effects</b>: Returns true if x and y are unequal
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator!=(const flat_set& x, const flat_set& y);

   //! <b>Effects</b>: Returns true if x is less than y
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator<(const flat_set& x, const flat_set& y);

   //! <b>Effects</b>: Returns true if x is greater than y
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator>(const flat_set& x, const flat_set& y);

   //! <b>Effects</b>: Returns true if x is equal or less than y
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator<=(const flat_set& x, const flat_set& y);

   //! <b>Effects</b>: Returns true if x is equal or greater than y
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator>=(const flat_set& x, const flat_set& y);

   //! <b>Effects</b>: x.swap(y)
   //!
   //! <b>Complexity</b>: Constant.
   friend void swap(flat_set& x, flat_set& y)
      BOOST_NOEXCEPT_IF(  allocator_traits_type::is_always_equal::value
                                 && boost::container::dtl::is_nothrow_swappable<Compare>::value );

   //! <b>Effects</b>: Extracts the internal sequence container.
   //!
   //! <b>Complexity</b>: Same as the move constructor of sequence_type, usually constant.
   //!
   //! <b>Postcondition</b>: this->empty()
   //!
   //! <b>Throws</b>: If secuence_type's move constructor throws 
   sequence_type extract_sequence();

   #endif   //#ifdef BOOST_CONTAINER_DOXYGEN_INVOKED

   //! <b>Effects</b>: Discards the internally hold sequence container and adopts the
   //!   one passed externally using the move assignment. Erases non-unique elements.
   //!
   //! <b>Complexity</b>: Assuming O(1) move assignment, O(NlogN) with N = seq.size()
   //!
   //! <b>Throws</b>: If the comparison or the move constructor throws
   BOOST_CONTAINER_FORCEINLINE void adopt_sequence(BOOST_RV_REF(sequence_type) seq)
   {  this->tree_t::adopt_sequence_unique(boost::move(seq));  }

   //! <b>Requires</b>: seq shall be ordered according to this->compare()
   //!   and shall contain unique elements.
   //!
   //! <b>Effects</b>: Discards the internally hold sequence container and adopts the
   //!   one passed externally using the move assignment.
   //!
   //! <b>Complexity</b>: Assuming O(1) move assignment, O(1)
   //!
   //! <b>Throws</b>: If the move assignment throws
   BOOST_CONTAINER_FORCEINLINE void adopt_sequence(ordered_unique_range_t, BOOST_RV_REF(sequence_type) seq)
   {  this->tree_t::adopt_sequence_unique(ordered_unique_range_t(), boost::move(seq));  }

   //! <b>Effects</b>: Returns a const view of the underlying sequence.
   //!
   //! <b>Complexity</b>: Constant
   //!
   //! <b>Throws</b>: Nothing
   BOOST_CONTAINER_FORCEINLINE const sequence_type & sequence() const BOOST_NOEXCEPT
   {  return this->get_sequence_cref();  }
};

#ifndef BOOST_CONTAINER_NO_CXX17_CTAD

template <typename InputIterator>
flat_set(InputIterator, InputIterator) ->
   flat_set< it_based_value_type_t<InputIterator> >;

template < typename InputIterator, typename AllocatorOrCompare>
    flat_set(InputIterator, InputIterator, AllocatorOrCompare const&) ->
    flat_set< it_based_value_type_t<InputIterator>
            , typename dtl::if_c< // Compare
                dtl::is_allocator<AllocatorOrCompare>::value
                , std::less<it_based_value_type_t<InputIterator>>
                , AllocatorOrCompare
            >::type
            , typename dtl::if_c< // Allocator
                dtl::is_allocator<AllocatorOrCompare>::value
                , AllocatorOrCompare
                , new_allocator<it_based_value_type_t<InputIterator>>
                >::type
            >;

template < typename InputIterator, typename Compare, typename Allocator
         , typename = dtl::require_nonallocator_t<Compare>
         , typename = dtl::require_allocator_t<Allocator>>
flat_set(InputIterator, InputIterator, Compare const&, Allocator const&) ->
   flat_set< it_based_value_type_t<InputIterator>
           , Compare
           , Allocator>;

template <typename InputIterator>
flat_set(ordered_unique_range_t, InputIterator, InputIterator) ->
   flat_set< it_based_value_type_t<InputIterator>>;


template < typename InputIterator, typename AllocatorOrCompare>
    flat_set(ordered_unique_range_t, InputIterator, InputIterator, AllocatorOrCompare const&) ->
    flat_set< it_based_value_type_t<InputIterator>
            , typename dtl::if_c< // Compare
                dtl::is_allocator<AllocatorOrCompare>::value
                , std::less<it_based_value_type_t<InputIterator>>
                , AllocatorOrCompare
            >::type
            , typename dtl::if_c< // Allocator
                dtl::is_allocator<AllocatorOrCompare>::value
                , AllocatorOrCompare
                , new_allocator<it_based_value_type_t<InputIterator>>
                >::type
            >;

template < typename InputIterator, typename Compare, typename Allocator
         , typename = dtl::require_nonallocator_t<Compare>
         , typename = dtl::require_allocator_t<Allocator>>
flat_set(ordered_unique_range_t, InputIterator, InputIterator, Compare const&, Allocator const&) ->
   flat_set< it_based_value_type_t<InputIterator>
           , Compare
           , Allocator>;

#endif

#ifndef BOOST_CONTAINER_DOXYGEN_INVOKED

}  //namespace container {

//!has_trivial_destructor_after_move<> == true_type
//!specialization for optimizations
template <class Key, class Compare, class AllocatorOrContainer>
struct has_trivial_destructor_after_move<boost::container::flat_set<Key, Compare, AllocatorOrContainer> >
{
   typedef ::boost::container::dtl::flat_tree<Key, ::boost::container::dtl::identity<Key>, Compare, AllocatorOrContainer> tree;
   static const bool value = ::boost::has_trivial_destructor_after_move<tree>::value;
};

namespace container {

#endif   //#ifndef BOOST_CONTAINER_DOXYGEN_INVOKED

//! flat_multiset is a Sorted Associative Container that stores objects of type Key and
//! can store multiple copies of the same key value.
//!
//! flat_multiset is similar to std::multiset but it's implemented by as an ordered sequence container.
//! The underlying sequence container is by default <i>vector</i> but it can also work
//! user-provided vector-like SequenceContainers (like <i>static_vector</i> or <i>small_vector</i>).
//!
//! Using vector-like sequence containers means that inserting a new element into a flat_multiset might invalidate
//! previous iterators and references (unless that sequence container is <i>stable_vector</i> or a similar
//! container that offers stable pointers and references). Similarly, erasing an element might invalidate
//! iterators and references pointing to elements that come after (their keys are bigger) the erased element.
//!
//! This container provides random-access iterators.
//!
//! \tparam Key is the type to be inserted in the multiset, which is also the key_type
//! \tparam Compare is the comparison functor used to order keys
//! \tparam AllocatorOrContainer is either:
//!   - The allocator to allocate <code>value_type</code>s (e.g. <i>allocator< std::pair<Key, T> > </i>).
//!     (in this case <i>sequence_type</i> will be vector<value_type, AllocatorOrContainer>)
//!   - The SequenceContainer to be used as the underlying <i>sequence_type</i>. It must be a vector-like
//!     sequence container with random-access iterators.
#ifdef BOOST_CONTAINER_DOXYGEN_INVOKED
template <class Key, class Compare = std::less<Key>, class AllocatorOrContainer = new_allocator<Key> >
#else
template <class Key, class Compare, class AllocatorOrContainer>
#endif
class flat_multiset
   ///@cond
   : public dtl::flat_tree<Key, dtl::identity<Key>, Compare, AllocatorOrContainer>
   ///@endcond
{
   #ifndef BOOST_CONTAINER_DOXYGEN_INVOKED
   private:
   BOOST_COPYABLE_AND_MOVABLE(flat_multiset)
   typedef dtl::flat_tree<Key, dtl::identity<Key>, Compare, AllocatorOrContainer> tree_t;

   public:
   tree_t &tree()
   {  return *this;  }

   const tree_t &tree() const
   {  return *this;  }
   #endif   //#ifndef BOOST_CONTAINER_DOXYGEN_INVOKED

   public:
   //////////////////////////////////////////////
   //
   //                    types
   //
   //////////////////////////////////////////////
   typedef Key                                                                      key_type;
   typedef Compare                                                                  key_compare;
   typedef Key                                                                      value_type;
   typedef typename BOOST_CONTAINER_IMPDEF(tree_t::sequence_type)                   sequence_type;
   typedef typename sequence_type::allocator_type                                   allocator_type;
   typedef ::boost::container::allocator_traits<allocator_type>                     allocator_traits_type;
   typedef typename sequence_type::pointer                                          pointer;
   typedef typename sequence_type::const_pointer                                    const_pointer;
   typedef typename sequence_type::reference                                        reference;
   typedef typename sequence_type::const_reference                                  const_reference;
   typedef typename sequence_type::size_type                                        size_type;
   typedef typename sequence_type::difference_type                                  difference_type;
   typedef typename BOOST_CONTAINER_IMPDEF(tree_t::stored_allocator_type)           stored_allocator_type;
   typedef typename BOOST_CONTAINER_IMPDEF(tree_t::value_compare)                   value_compare;

   typedef typename sequence_type::iterator                                         iterator;
   typedef typename sequence_type::const_iterator                                   const_iterator;
   typedef typename sequence_type::reverse_iterator                                 reverse_iterator;
   typedef typename sequence_type::const_reverse_iterator                           const_reverse_iterator;

   //! @copydoc ::boost::container::flat_set::flat_set()
   BOOST_CONTAINER_FORCEINLINE flat_multiset() BOOST_NOEXCEPT_IF(dtl::is_nothrow_default_constructible<AllocatorOrContainer>::value &&
                                                                 dtl::is_nothrow_default_constructible<Compare>::value)
      : tree_t()
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(const Compare&)
   BOOST_CONTAINER_FORCEINLINE explicit flat_multiset(const Compare& comp)
      : tree_t(comp)
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(const allocator_type&)
   BOOST_CONTAINER_FORCEINLINE explicit flat_multiset(const allocator_type& a)
      : tree_t(a)
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(const Compare&, const allocator_type&)
   BOOST_CONTAINER_FORCEINLINE flat_multiset(const Compare& comp, const allocator_type& a)
      : tree_t(comp, a)
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(InputIterator, InputIterator)
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE flat_multiset(InputIterator first, InputIterator last)
      : tree_t(false, first, last)
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(InputIterator, InputIterator, const allocator_type&)
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE flat_multiset(InputIterator first, InputIterator last, const allocator_type& a)
      : tree_t(false, first, last, a)
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(InputIterator, InputIterator, const Compare& comp)
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE flat_multiset(InputIterator first, InputIterator last, const Compare& comp)
      : tree_t(false, first, last, comp)
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(InputIterator, InputIterator, const Compare& comp, const allocator_type&)
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE flat_multiset(InputIterator first, InputIterator last, const Compare& comp, const allocator_type& a)
      : tree_t(false, first, last, comp, a)
   {}

   //! <b>Effects</b>: Constructs an empty flat_multiset and
   //! inserts elements from the ordered range [first ,last ). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [first ,last) must be ordered according to the predicate.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE flat_multiset(ordered_range_t, InputIterator first, InputIterator last)
      : tree_t(ordered_range, first, last)
   {}

   //! <b>Effects</b>: Constructs an empty flat_multiset using the specified comparison object and
   //! inserts elements from the ordered range [first ,last ). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [first ,last) must be ordered according to the predicate.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE flat_multiset(ordered_range_t, InputIterator first, InputIterator last, const Compare& comp)
      : tree_t(ordered_range, first, last, comp)
   {}

   //! <b>Effects</b>: Constructs an empty flat_multiset using the specified comparison object and
   //! allocator, and inserts elements from the ordered range [first, last ). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [first ,last) must be ordered according to the predicate.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE flat_multiset(ordered_range_t, InputIterator first, InputIterator last, const Compare& comp, const allocator_type& a)
      : tree_t(ordered_range, first, last, comp, a)
   {}

   //! <b>Effects</b>: Constructs an empty flat_multiset using the specified allocator and
   //! inserts elements from the ordered range [first ,last ). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [first ,last) must be ordered according to the predicate.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE flat_multiset(ordered_range_t, InputIterator first, InputIterator last, const allocator_type &a)
      : tree_t(ordered_range, first, last, Compare(), a)
   {}

#if !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST)
   //! @copydoc ::boost::container::flat_set::flat_set(std::initializer_list<value_type)
   BOOST_CONTAINER_FORCEINLINE flat_multiset(std::initializer_list<value_type> il)
      : tree_t(false, il.begin(), il.end())
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(std::initializer_list<value_type>, const allocator_type&)
   BOOST_CONTAINER_FORCEINLINE flat_multiset(std::initializer_list<value_type> il, const allocator_type& a)
      : tree_t(false, il.begin(), il.end(), a)
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(std::initializer_list<value_type>, const Compare& comp)
   BOOST_CONTAINER_FORCEINLINE flat_multiset(std::initializer_list<value_type> il, const Compare& comp)
      : tree_t(false, il.begin(), il.end(), comp)
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(std::initializer_list<value_type>, const Compare& comp, const allocator_type&)
   BOOST_CONTAINER_FORCEINLINE flat_multiset(std::initializer_list<value_type> il, const Compare& comp, const allocator_type& a)
      : tree_t(false, il.begin(), il.end(), comp, a)
   {}

   //! <b>Effects</b>: Constructs an empty containerand
   //! inserts elements from the ordered unique range [il.begin(), il.end()). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [il.begin(), il.end()) must be ordered according to the predicate.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   BOOST_CONTAINER_FORCEINLINE flat_multiset(ordered_range_t, std::initializer_list<value_type> il)
      : tree_t(ordered_range, il.begin(), il.end())
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! inserts elements from the ordered unique range [il.begin(), il.end()). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [il.begin(), il.end()) must be ordered according to the predicate.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   BOOST_CONTAINER_FORCEINLINE flat_multiset(ordered_range_t, std::initializer_list<value_type> il, const Compare& comp)
      : tree_t(ordered_range, il.begin(), il.end(), comp)
   {}

   //! <b>Effects</b>: Constructs an empty container using the specified comparison object and
   //! allocator, and inserts elements from the ordered unique range [il.begin(), il.end()). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Requires</b>: [il.begin(), il.end()) must be ordered according to the predicate.
   //!
   //! <b>Complexity</b>: Linear in N.
   //!
   //! <b>Note</b>: Non-standard extension.
   BOOST_CONTAINER_FORCEINLINE flat_multiset(ordered_range_t, std::initializer_list<value_type> il, const Compare& comp, const allocator_type& a)
      : tree_t(ordered_range, il.begin(), il.end(), comp, a)
   {}
#endif

   //! @copydoc ::boost::container::flat_set::flat_set(const flat_set &)
   BOOST_CONTAINER_FORCEINLINE flat_multiset(const flat_multiset& x)
      : tree_t(static_cast<const tree_t&>(x))
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(flat_set &&)
   BOOST_CONTAINER_FORCEINLINE flat_multiset(BOOST_RV_REF(flat_multiset) x)
      BOOST_NOEXCEPT_IF(boost::container::dtl::is_nothrow_move_constructible<Compare>::value)
      : tree_t(boost::move(static_cast<tree_t&>(x)))
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(const flat_set &, const allocator_type &)
   BOOST_CONTAINER_FORCEINLINE flat_multiset(const flat_multiset& x, const allocator_type &a)
      : tree_t(static_cast<const tree_t&>(x), a)
   {}

   //! @copydoc ::boost::container::flat_set::flat_set(flat_set &&, const allocator_type &)
   BOOST_CONTAINER_FORCEINLINE flat_multiset(BOOST_RV_REF(flat_multiset) x, const allocator_type &a)
      : tree_t(BOOST_MOVE_BASE(tree_t, x), a)
   {}

   //! @copydoc ::boost::container::flat_set::operator=(const flat_set &)
   BOOST_CONTAINER_FORCEINLINE flat_multiset& operator=(BOOST_COPY_ASSIGN_REF(flat_multiset) x)
   {  return static_cast<flat_multiset&>(this->tree_t::operator=(static_cast<const tree_t&>(x)));  }

   //! @copydoc ::boost::container::flat_set::operator=(flat_set &&)
   BOOST_CONTAINER_FORCEINLINE flat_multiset& operator=(BOOST_RV_REF(flat_multiset) x)
      BOOST_NOEXCEPT_IF( (allocator_traits_type::propagate_on_container_move_assignment::value ||
                          allocator_traits_type::is_always_equal::value) &&
                           boost::container::dtl::is_nothrow_move_assignable<Compare>::value)
   {  return static_cast<flat_multiset&>(this->tree_t::operator=(BOOST_MOVE_BASE(tree_t, x)));  }

#if !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST)
   //! @copydoc ::boost::container::flat_set::operator=(std::initializer_list<value_type>)
   flat_multiset& operator=(std::initializer_list<value_type> il)
   {
       this->clear();
       this->insert(il.begin(), il.end());
       return *this;
   }
#endif

   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //! @copydoc ::boost::container::flat_set::get_allocator()
   allocator_type get_allocator() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::get_stored_allocator()
   stored_allocator_type &get_stored_allocator() BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::get_stored_allocator() const
   const stored_allocator_type &get_stored_allocator() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::begin()
   iterator begin() BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::begin() const
   const_iterator begin() const;

   //! @copydoc ::boost::container::flat_set::cbegin() const
   const_iterator cbegin() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::end()
   iterator end() BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::end() const
   const_iterator end() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::cend() const
   const_iterator cend() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::rbegin()
   reverse_iterator rbegin() BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::rbegin() const
   const_reverse_iterator rbegin() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::crbegin() const
   const_reverse_iterator crbegin() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::rend()
   reverse_iterator rend() BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::rend() const
   const_reverse_iterator rend() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::crend() const
   const_reverse_iterator crend() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::empty() const
   bool empty() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::size() const
   size_type size() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::max_size() const
   size_type max_size() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::capacity() const
   size_type capacity() const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::reserve(size_type)
   void reserve(size_type cnt);

   //! @copydoc ::boost::container::flat_set::shrink_to_fit()
   void shrink_to_fit();

   #endif   //   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //////////////////////////////////////////////
   //
   //                modifiers
   //
   //////////////////////////////////////////////

   #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) || defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //! <b>Effects</b>: Inserts an object of type Key constructed with
   //!   std::forward<Args>(args)... and returns the iterator pointing to the
   //!   newly inserted element.
   //!
   //! <b>Complexity</b>: Logarithmic search time plus linear insertion
   //!   to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   template <class... Args>
   BOOST_CONTAINER_FORCEINLINE iterator emplace(BOOST_FWD_REF(Args)... args)
   {  return this->tree_t::emplace_equal(boost::forward<Args>(args)...); }

   //! <b>Effects</b>: Inserts an object of type Key constructed with
   //!   std::forward<Args>(args)... in the container.
   //!   p is a hint pointing to where the insert should start to search.
   //!
   //! <b>Returns</b>: An iterator pointing to the element with key equivalent
   //!   to the key of x.
   //!
   //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
   //!   right before p) plus insertion linear to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   template <class... Args>
   BOOST_CONTAINER_FORCEINLINE iterator emplace_hint(const_iterator p, BOOST_FWD_REF(Args)... args)
   {  return this->tree_t::emplace_hint_equal(p, boost::forward<Args>(args)...); }

   #else // !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

   #define BOOST_CONTAINER_FLAT_MULTISET_EMPLACE_CODE(N) \
   BOOST_MOVE_TMPL_LT##N BOOST_MOVE_CLASS##N BOOST_MOVE_GT##N \
   BOOST_CONTAINER_FORCEINLINE iterator emplace(BOOST_MOVE_UREF##N)\
   {  return this->tree_t::emplace_equal(BOOST_MOVE_FWD##N);  }\
   \
   BOOST_MOVE_TMPL_LT##N BOOST_MOVE_CLASS##N BOOST_MOVE_GT##N \
   BOOST_CONTAINER_FORCEINLINE iterator emplace_hint(const_iterator hint BOOST_MOVE_I##N BOOST_MOVE_UREF##N)\
   {  return this->tree_t::emplace_hint_equal(hint BOOST_MOVE_I##N BOOST_MOVE_FWD##N); }\
   //
   BOOST_MOVE_ITERATE_0TO9(BOOST_CONTAINER_FLAT_MULTISET_EMPLACE_CODE)
   #undef BOOST_CONTAINER_FLAT_MULTISET_EMPLACE_CODE

   #endif   // !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)

   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
   //! <b>Effects</b>: Inserts x and returns the iterator pointing to the
   //!   newly inserted element.
   //!
   //! <b>Complexity</b>: Logarithmic search time plus linear insertion
   //!   to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   iterator insert(const value_type &x);

   //! <b>Effects</b>: Inserts a new value_type move constructed from x
   //!   and returns the iterator pointing to the newly inserted element.
   //!
   //! <b>Complexity</b>: Logarithmic search time plus linear insertion
   //!   to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   iterator insert(value_type &&x);
   #else
   BOOST_MOVE_CONVERSION_AWARE_CATCH(insert, value_type, iterator, this->tree_t::insert_equal)
   #endif

   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
   //! <b>Effects</b>: Inserts a copy of x in the container.
   //!   p is a hint pointing to where the insert should start to search.
   //!
   //! <b>Returns</b>: An iterator pointing to the element with key equivalent
   //!   to the key of x.
   //!
   //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
   //!   right before p) plus insertion linear to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   iterator insert(const_iterator p, const value_type &x);

   //! <b>Effects</b>: Inserts a new value move constructed  from x in the container.
   //!   p is a hint pointing to where the insert should start to search.
   //!
   //! <b>Returns</b>: An iterator pointing to the element with key equivalent
   //!   to the key of x.
   //!
   //! <b>Complexity</b>: Logarithmic search time (constant if x is inserted
   //!   right before p) plus insertion linear to the elements with bigger keys than x.
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   iterator insert(const_iterator p, value_type &&x);
   #else
   BOOST_MOVE_CONVERSION_AWARE_CATCH_1ARG(insert, value_type, iterator, this->tree_t::insert_equal, const_iterator, const_iterator)
   #endif

   //! <b>Requires</b>: first, last are not iterators into *this.
   //!
   //! <b>Effects</b>: inserts each element from the range [first,last) .
   //!
   //! <b>Complexity</b>: N log(N).
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE void insert(InputIterator first, InputIterator last)
      {  this->tree_t::insert_equal(first, last);  }

   //! <b>Requires</b>: first, last are not iterators into *this and
   //! must be ordered according to the predicate.
   //!
   //! <b>Effects</b>: inserts each element from the range [first,last) .This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Complexity</b>: Linear.
   //!
   //! <b>Note</b>: Non-standard extension. If an element is inserted it might invalidate elements.
   template <class InputIterator>
   BOOST_CONTAINER_FORCEINLINE void insert(ordered_range_t, InputIterator first, InputIterator last)
      {  this->tree_t::insert_equal(ordered_range, first, last);  }

#if !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST)
   //! <b>Effects</b>: inserts each element from the range [il.begin(), il.end()).
   //!
   //! <b>Complexity</b>: N log(N).
   //!
   //! <b>Note</b>: If an element is inserted it might invalidate elements.
   BOOST_CONTAINER_FORCEINLINE void insert(std::initializer_list<value_type> il)
   {  this->tree_t::insert_equal(il.begin(), il.end()); }

   //! <b>Requires</b>: Range [il.begin(), il.end()) must be ordered according to the predicate.
   //!
   //! <b>Effects</b>: inserts each element from the range [il.begin(), il.end()). This function
   //! is more efficient than the normal range creation for ordered ranges.
   //!
   //! <b>Complexity</b>: Linear.
   //!
   //! <b>Note</b>: Non-standard extension. If an element is inserted it might invalidate elements.
   BOOST_CONTAINER_FORCEINLINE void insert(ordered_range_t, std::initializer_list<value_type> il)
   {  this->tree_t::insert_equal(ordered_range, il.begin(), il.end()); }
#endif

   //! @copydoc ::boost::container::flat_multimap::merge(flat_multimap<Key, T, C2, AllocatorOrContainer>&)
   template<class C2>
   BOOST_CONTAINER_FORCEINLINE void merge(flat_multiset<Key, C2, AllocatorOrContainer>& source)
   {  this->tree_t::merge_equal(source.tree());   }

   //! @copydoc ::boost::container::flat_multiset::merge(flat_multiset<Key, C2, AllocatorOrContainer>&)
   template<class C2>
   BOOST_CONTAINER_FORCEINLINE void merge(BOOST_RV_REF_BEG flat_multiset<Key, C2, AllocatorOrContainer> BOOST_RV_REF_END source)
   {  return this->merge(static_cast<flat_multiset<Key, C2, AllocatorOrContainer>&>(source));   }

   //! @copydoc ::boost::container::flat_multimap::merge(flat_map<Key, T, C2, AllocatorOrContainer>&)
   template<class C2>
   BOOST_CONTAINER_FORCEINLINE void merge(flat_set<Key, C2, AllocatorOrContainer>& source)
   {  this->tree_t::merge_equal(source.tree());   }

   //! @copydoc ::boost::container::flat_multiset::merge(flat_set<Key, C2, AllocatorOrContainer>&)
   template<class C2>
   BOOST_CONTAINER_FORCEINLINE void merge(BOOST_RV_REF_BEG flat_set<Key, C2, AllocatorOrContainer> BOOST_RV_REF_END source)
   {  return this->merge(static_cast<flat_set<Key, C2, AllocatorOrContainer>&>(source));   }

   #if defined(BOOST_CONTAINER_DOXYGEN_INVOKED)

   //! @copydoc ::boost::container::flat_set::erase(const_iterator)
   iterator erase(const_iterator p);

   //! @copydoc ::boost::container::flat_set::erase(const key_type&)
   size_type erase(const key_type& x);

   //! @copydoc ::boost::container::flat_set::erase(const_iterator,const_iterator)
   iterator erase(const_iterator first, const_iterator last);

   //! @copydoc ::boost::container::flat_set::swap
   void swap(flat_multiset& x)
      BOOST_NOEXCEPT_IF(  allocator_traits_type::is_always_equal::value
                                 && boost::container::dtl::is_nothrow_swappable<Compare>::value );

   //! @copydoc ::boost::container::flat_set::clear
   void clear() BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::key_comp
   key_compare key_comp() const;

   //! @copydoc ::boost::container::flat_set::value_comp
   value_compare value_comp() const;

   //! @copydoc ::boost::container::flat_set::find(const key_type& )
   iterator find(const key_type& x);

   //! @copydoc ::boost::container::flat_set::find(const key_type& ) const
   const_iterator find(const key_type& x) const;

   //! @copydoc ::boost::container::flat_set::nth(size_type)
   iterator nth(size_type n) BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::nth(size_type) const
   const_iterator nth(size_type n) const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::index_of(iterator)
   size_type index_of(iterator p) BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::index_of(const_iterator) const
   size_type index_of(const_iterator p) const BOOST_NOEXCEPT_OR_NOTHROW;

   //! @copydoc ::boost::container::flat_set::count(const key_type& ) const
   size_type count(const key_type& x) const;

   //! @copydoc ::boost::container::flat_set::contains(const key_type& ) const
   bool contains(const key_type& x) const;

   //! @copydoc ::boost::container::flat_set::contains(const K& ) const
   template<typename K>
   bool contains(const K& x) const;

   //! @copydoc ::boost::container::flat_set::lower_bound(const key_type& )
   iterator lower_bound(const key_type& x);

   //! @copydoc ::boost::container::flat_set::lower_bound(const key_type& ) const
   const_iterator lower_bound(const key_type& x) const;

   //! @copydoc ::boost::container::flat_set::upper_bound(const key_type& )
   iterator upper_bound(const key_type& x);

   //! @copydoc ::boost::container::flat_set::upper_bound(const key_type& ) const
   const_iterator upper_bound(const key_type& x) const;

   //! @copydoc ::boost::container::flat_set::equal_range(const key_type& ) const
   std::pair<const_iterator, const_iterator> equal_range(const key_type& x) const;

   //! @copydoc ::boost::container::flat_set::equal_range(const key_type& )
   std::pair<iterator,iterator> equal_range(const key_type& x);

   //! <b>Effects</b>: Returns true if x and y are equal
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator==(const flat_multiset& x, const flat_multiset& y);

   //! <b>Effects</b>: Returns true if x and y are unequal
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator!=(const flat_multiset& x, const flat_multiset& y);

   //! <b>Effects</b>: Returns true if x is less than y
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator<(const flat_multiset& x, const flat_multiset& y);

   //! <b>Effects</b>: Returns true if x is greater than y
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator>(const flat_multiset& x, const flat_multiset& y);

   //! <b>Effects</b>: Returns true if x is equal or less than y
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator<=(const flat_multiset& x, const flat_multiset& y);

   //! <b>Effects</b>: Returns true if x is equal or greater than y
   //!
   //! <b>Complexity</b>: Linear to the number of elements in the container.
   friend bool operator>=(const flat_multiset& x, const flat_multiset& y);

   //! <b>Effects</b>: x.swap(y)
   //!
   //! <b>Complexity</b>: Constant.
   friend void swap(flat_multiset& x, flat_multiset& y)
      BOOST_NOEXCEPT_IF(  allocator_traits_type::is_always_equal::value
                                 && boost::container::dtl::is_nothrow_swappable<Compare>::value );

   //! <b>Effects</b>: Extracts the internal sequence container.
   //!
   //! <b>Complexity</b>: Same as the move constructor of sequence_type, usually constant.
   //!
   //! <b>Postcondition</b>: this->empty()
   //!
   //! <b>Throws</b>: If secuence_type's move constructor throws 
   sequence_type extract_sequence();

   #endif   //#ifdef BOOST_CONTAINER_DOXYGEN_INVOKED

   //! <b>Effects</b>: Discards the internally hold sequence container and adopts the
   //!   one passed externally using the move assignment.
   //!
   //! <b>Complexity</b>: Assuming O(1) move assignment, O(NlogN) with N = seq.size()
   //!
   //! <b>Throws</b>: If the comparison or the move constructor throws
   BOOST_CONTAINER_FORCEINLINE void adopt_sequence(BOOST_RV_REF(sequence_type) seq)
   {  this->tree_t::adopt_sequence_equal(boost::move(seq));  }

   //! <b>Requires</b>: seq shall be ordered according to this->compare()
   //!
   //! <b>Effects</b>: Discards the internally hold sequence container and adopts the
   //!   one passed externally using the move assignment.
   //!
   //! <b>Complexity</b>: Assuming O(1) move assignment, O(1)
   //!
   //! <b>Throws</b>: If the move assignment throws
   BOOST_CONTAINER_FORCEINLINE void adopt_sequence(ordered_range_t, BOOST_RV_REF(sequence_type) seq)
   {  this->tree_t::adopt_sequence_equal(ordered_range_t(), boost::move(seq));  }

   //! <b>Effects</b>: Returns a const view of the underlying sequence.
   //!
   //! <b>Complexity</b>: Constant
   //!
   //! <b>Throws</b>: Nothing
   BOOST_CONTAINER_FORCEINLINE const sequence_type & sequence() const BOOST_NOEXCEPT
   {  return this->get_sequence_cref();  }
};

#ifndef BOOST_CONTAINER_NO_CXX17_CTAD

template <typename InputIterator>
flat_multiset(InputIterator, InputIterator) ->
   flat_multiset< it_based_value_type_t<InputIterator> >;


template < typename InputIterator, typename AllocatorOrCompare>
flat_multiset(InputIterator, InputIterator, AllocatorOrCompare const&) ->
    flat_multiset < it_based_value_type_t<InputIterator>
                  , typename dtl::if_c< // Compare
                      dtl::is_allocator<AllocatorOrCompare>::value
                      , std::less<it_based_value_type_t<InputIterator>>
                      , AllocatorOrCompare
                  >::type
                  , typename dtl::if_c< // Allocator
                      dtl::is_allocator<AllocatorOrCompare>::value
                      , AllocatorOrCompare
                      , new_allocator<it_based_value_type_t<InputIterator>>
                      >::type
                  >;

template < typename InputIterator, typename Compare, typename Allocator
         , typename = dtl::require_nonallocator_t<Compare>
         , typename = dtl::require_allocator_t<Allocator>>
flat_multiset(InputIterator, InputIterator, Compare const&, Allocator const&) ->
   flat_multiset< it_based_value_type_t<InputIterator>
           , Compare
           , Allocator>;

template <typename InputIterator>
flat_multiset(ordered_range_t, InputIterator, InputIterator) ->
   flat_multiset< it_based_value_type_t<InputIterator>>;

template < typename InputIterator, typename AllocatorOrCompare>
flat_multiset(ordered_range_t, InputIterator, InputIterator, AllocatorOrCompare const&) ->
    flat_multiset < it_based_value_type_t<InputIterator>
                  , typename dtl::if_c< // Compare
                      dtl::is_allocator<AllocatorOrCompare>::value
                      , std::less<it_based_value_type_t<InputIterator>>
                      , AllocatorOrCompare
                  >::type
                  , typename dtl::if_c< // Allocator
                      dtl::is_allocator<AllocatorOrCompare>::value
                      , AllocatorOrCompare
                      , new_allocator<it_based_value_type_t<InputIterator>>
                      >::type
                  >;

template < typename InputIterator, typename Compare, typename Allocator
         , typename = dtl::require_nonallocator_t<Compare>
         , typename = dtl::require_allocator_t<Allocator>>
flat_multiset(ordered_range_t, InputIterator, InputIterator, Compare const&, Allocator const&) ->
   flat_multiset< it_based_value_type_t<InputIterator>
           , Compare
           , Allocator>;

#endif

#ifndef BOOST_CONTAINER_DOXYGEN_INVOKED

}  //namespace container {

//!has_trivial_destructor_after_move<> == true_type
//!specialization for optimizations
template <class Key, class Compare, class AllocatorOrContainer>
struct has_trivial_destructor_after_move<boost::container::flat_multiset<Key, Compare, AllocatorOrContainer> >
{
   typedef ::boost::container::dtl::flat_tree<Key, ::boost::container::dtl::identity<Key>, Compare, AllocatorOrContainer> tree;
   static const bool value = ::boost::has_trivial_destructor_after_move<tree>::value;
};

namespace container {

#endif   //#ifndef BOOST_CONTAINER_DOXYGEN_INVOKED

}}

#include <boost/container/detail/config_end.hpp>

#endif   // BOOST_CONTAINER_FLAT_SET_HPP