525 lines
15 KiB
C++
525 lines
15 KiB
C++
// boost heap
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//
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// Copyright (C) 2010 Tim Blechmann
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_HEAP_DETAIL_MUTABLE_HEAP_HPP
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#define BOOST_HEAP_DETAIL_MUTABLE_HEAP_HPP
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/*! \file
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* INTERNAL ONLY
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*/
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#include <list>
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#include <utility>
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#include <boost/iterator/iterator_adaptor.hpp>
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#include <boost/heap/detail/ordered_adaptor_iterator.hpp>
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namespace boost {
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namespace heap {
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namespace detail {
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/* wrapper for a mutable heap container adaptors
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*
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* this wrapper introduces an additional indirection. the heap is not constructed from objects,
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* but instead from std::list iterators. this way, the mutability is achieved
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*
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*/
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template <typename PriorityQueueType>
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class priority_queue_mutable_wrapper
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{
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public:
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typedef typename PriorityQueueType::value_type value_type;
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typedef typename PriorityQueueType::size_type size_type;
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typedef typename PriorityQueueType::value_compare value_compare;
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typedef typename PriorityQueueType::allocator_type allocator_type;
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typedef typename PriorityQueueType::reference reference;
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typedef typename PriorityQueueType::const_reference const_reference;
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typedef typename PriorityQueueType::pointer pointer;
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typedef typename PriorityQueueType::const_pointer const_pointer;
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static const bool is_stable = PriorityQueueType::is_stable;
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private:
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typedef std::pair<value_type, size_type> node_type;
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typedef std::list<node_type, typename allocator_type::template rebind<node_type>::other> object_list;
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typedef typename object_list::iterator list_iterator;
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typedef typename object_list::const_iterator const_list_iterator;
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template <typename Heap1, typename Heap2>
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friend struct heap_merge_emulate;
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typedef typename PriorityQueueType::super_t::stability_counter_type stability_counter_type;
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stability_counter_type get_stability_count(void) const
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{
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return q_.get_stability_count();
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}
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void set_stability_count(stability_counter_type new_count)
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{
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q_.set_stability_count(new_count);
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}
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struct index_updater
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{
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template <typename It>
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static void run(It & it, size_type new_index)
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{
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q_type::get_value(it)->second = new_index;
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}
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};
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public:
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struct handle_type
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{
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value_type & operator*() const
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{
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return iterator->first;
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}
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handle_type (void)
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{}
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handle_type(handle_type const & rhs):
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iterator(rhs.iterator)
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{}
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bool operator==(handle_type const & rhs) const
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{
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return iterator == rhs.iterator;
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}
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bool operator!=(handle_type const & rhs) const
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{
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return iterator != rhs.iterator;
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}
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private:
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explicit handle_type(list_iterator const & it):
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iterator(it)
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{}
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list_iterator iterator;
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friend class priority_queue_mutable_wrapper;
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};
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private:
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struct indirect_cmp:
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public value_compare
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{
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indirect_cmp(value_compare const & cmp = value_compare()):
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value_compare(cmp)
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{}
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bool operator()(const_list_iterator const & lhs, const_list_iterator const & rhs) const
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{
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return value_compare::operator()(lhs->first, rhs->first);
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}
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};
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typedef typename PriorityQueueType::template rebind<list_iterator,
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indirect_cmp,
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allocator_type, index_updater >::other q_type;
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protected:
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q_type q_;
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object_list objects;
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protected:
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priority_queue_mutable_wrapper(value_compare const & cmp = value_compare()):
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q_(cmp)
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{}
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priority_queue_mutable_wrapper(priority_queue_mutable_wrapper const & rhs):
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q_(rhs.q_), objects(rhs.objects)
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{
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for (typename object_list::iterator it = objects.begin(); it != objects.end(); ++it)
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q_.push(it);
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}
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priority_queue_mutable_wrapper & operator=(priority_queue_mutable_wrapper const & rhs)
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{
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q_ = rhs.q_;
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objects = rhs.objects;
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q_.clear();
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for (typename object_list::iterator it = objects.begin(); it != objects.end(); ++it)
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q_.push(it);
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return *this;
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}
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#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
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priority_queue_mutable_wrapper (priority_queue_mutable_wrapper && rhs):
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q_(std::move(rhs.q_))
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{
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/// FIXME: msvc seems to invalidate iterators when moving std::list
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std::swap(objects, rhs.objects);
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}
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priority_queue_mutable_wrapper & operator=(priority_queue_mutable_wrapper && rhs)
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{
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q_ = std::move(rhs.q_);
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objects.clear();
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std::swap(objects, rhs.objects);
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return *this;
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}
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#endif
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public:
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template <typename iterator_type>
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class iterator_base:
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public boost::iterator_adaptor<iterator_base<iterator_type>,
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iterator_type,
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value_type const,
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boost::bidirectional_traversal_tag>
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{
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typedef boost::iterator_adaptor<iterator_base<iterator_type>,
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iterator_type,
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value_type const,
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boost::bidirectional_traversal_tag> super_t;
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friend class boost::iterator_core_access;
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friend class priority_queue_mutable_wrapper;
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iterator_base(void):
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super_t(0)
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{}
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template <typename T>
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explicit iterator_base(T const & it):
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super_t(it)
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{}
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value_type const & dereference() const
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{
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return super_t::base()->first;
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}
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iterator_type get_list_iterator() const
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{
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return super_t::base_reference();
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}
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};
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typedef iterator_base<list_iterator> iterator;
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typedef iterator_base<const_list_iterator> const_iterator;
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typedef typename object_list::difference_type difference_type;
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class ordered_iterator:
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public boost::iterator_adaptor<ordered_iterator,
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const_list_iterator,
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value_type const,
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boost::forward_traversal_tag
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>,
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q_type::ordered_iterator_dispatcher
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{
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typedef boost::iterator_adaptor<ordered_iterator,
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const_list_iterator,
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value_type const,
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boost::forward_traversal_tag
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> adaptor_type;
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typedef const_list_iterator iterator;
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typedef typename q_type::ordered_iterator_dispatcher ordered_iterator_dispatcher;
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friend class boost::iterator_core_access;
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public:
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ordered_iterator(void):
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adaptor_type(0), unvisited_nodes(indirect_cmp()), q_(NULL)
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{}
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ordered_iterator(const priority_queue_mutable_wrapper * q, indirect_cmp const & cmp):
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adaptor_type(0), unvisited_nodes(cmp), q_(q)
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{}
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ordered_iterator(const_list_iterator it, const priority_queue_mutable_wrapper * q, indirect_cmp const & cmp):
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adaptor_type(it), unvisited_nodes(cmp), q_(q)
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{
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if (it != q->objects.end())
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discover_nodes(it);
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}
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bool operator!=(ordered_iterator const & rhs) const
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{
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return adaptor_type::base() != rhs.base();
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}
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bool operator==(ordered_iterator const & rhs) const
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{
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return !operator!=(rhs);
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}
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private:
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void increment(void)
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{
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if (unvisited_nodes.empty())
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adaptor_type::base_reference() = q_->objects.end();
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else {
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iterator next = unvisited_nodes.top();
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unvisited_nodes.pop();
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discover_nodes(next);
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adaptor_type::base_reference() = next;
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}
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}
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value_type const & dereference() const
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{
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return adaptor_type::base()->first;
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}
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void discover_nodes(iterator current)
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{
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size_type current_index = current->second;
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const q_type * q = &(q_->q_);
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if (ordered_iterator_dispatcher::is_leaf(q, current_index))
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return;
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std::pair<size_type, size_type> child_range = ordered_iterator_dispatcher::get_child_nodes(q, current_index);
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for (size_type i = child_range.first; i <= child_range.second; ++i) {
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typename q_type::internal_type const & internal_value_at_index = ordered_iterator_dispatcher::get_internal_value(q, i);
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typename q_type::value_type const & value_at_index = q_->q_.get_value(internal_value_at_index);
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unvisited_nodes.push(value_at_index);
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}
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}
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std::priority_queue<iterator,
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std::vector<iterator, typename allocator_type::template rebind<iterator>::other >,
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indirect_cmp
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> unvisited_nodes;
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const priority_queue_mutable_wrapper * q_;
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};
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bool empty(void) const
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{
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return q_.empty();
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}
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size_type size(void) const
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{
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return q_.size();
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}
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size_type max_size(void) const
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{
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return objects.max_size();
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}
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void clear(void)
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{
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q_.clear();
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objects.clear();
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}
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allocator_type get_allocator(void) const
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{
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return q_.get_allocator();
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}
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void swap(priority_queue_mutable_wrapper & rhs)
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{
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objects.swap(rhs.objects);
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q_.swap(rhs.q_);
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}
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const_reference top(void) const
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{
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BOOST_ASSERT(!empty());
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return q_.top()->first;
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}
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handle_type push(value_type const & v)
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{
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objects.push_front(std::make_pair(v, 0));
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list_iterator ret = objects.begin();
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q_.push(ret);
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return handle_type(ret);
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}
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#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
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template <class... Args>
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handle_type emplace(Args&&... args)
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{
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objects.push_front(std::make_pair(std::forward<Args>(args)..., 0));
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list_iterator ret = objects.begin();
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q_.push(ret);
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return handle_type(ret);
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}
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#endif
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void pop(void)
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{
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BOOST_ASSERT(!empty());
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list_iterator q_top = q_.top();
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q_.pop();
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objects.erase(q_top);
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}
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/**
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* \b Effects: Assigns \c v to the element handled by \c handle & updates the priority queue.
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*
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* \b Complexity: Logarithmic.
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*
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* */
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void update(handle_type handle, const_reference v)
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{
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list_iterator it = handle.iterator;
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value_type const & current_value = it->first;
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value_compare const & cmp = q_.value_comp();
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if (cmp(v, current_value))
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decrease(handle, v);
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else
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increase(handle, v);
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}
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/**
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* \b Effects: Updates the heap after the element handled by \c handle has been changed.
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*
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* \b Complexity: Logarithmic.
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*
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* \b Note: If this is not called, after a handle has been updated, the behavior of the data structure is undefined!
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* */
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void update(handle_type handle)
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{
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list_iterator it = handle.iterator;
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size_type index = it->second;
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q_.update(index);
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}
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/**
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* \b Effects: Assigns \c v to the element handled by \c handle & updates the priority queue.
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*
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* \b Complexity: Logarithmic.
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*
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* \b Note: The new value is expected to be greater than the current one
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* */
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void increase(handle_type handle, const_reference v)
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{
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BOOST_ASSERT(!value_compare()(v, handle.iterator->first));
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handle.iterator->first = v;
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increase(handle);
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}
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/**
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* \b Effects: Updates the heap after the element handled by \c handle has been changed.
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*
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* \b Complexity: Logarithmic.
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*
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* \b Note: The new value is expected to be greater than the current one. If this is not called, after a handle has been updated, the behavior of the data structure is undefined!
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* */
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void increase(handle_type handle)
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{
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list_iterator it = handle.iterator;
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size_type index = it->second;
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q_.increase(index);
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}
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/**
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* \b Effects: Assigns \c v to the element handled by \c handle & updates the priority queue.
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*
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* \b Complexity: Logarithmic.
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*
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* \b Note: The new value is expected to be less than the current one
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* */
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void decrease(handle_type handle, const_reference v)
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{
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BOOST_ASSERT(!value_compare()(handle.iterator->first, v));
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handle.iterator->first = v;
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decrease(handle);
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}
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/**
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* \b Effects: Updates the heap after the element handled by \c handle has been changed.
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*
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* \b Complexity: Logarithmic.
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*
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* \b Note: The new value is expected to be less than the current one. If this is not called, after a handle has been updated, the behavior of the data structure is undefined!
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* */
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void decrease(handle_type handle)
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{
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list_iterator it = handle.iterator;
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size_type index = it->second;
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q_.decrease(index);
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}
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/**
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* \b Effects: Removes the element handled by \c handle from the priority_queue.
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*
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* \b Complexity: Logarithmic.
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* */
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void erase(handle_type handle)
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{
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list_iterator it = handle.iterator;
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size_type index = it->second;
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q_.erase(index);
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objects.erase(it);
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}
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const_iterator begin(void) const
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{
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return const_iterator(objects.begin());
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}
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const_iterator end(void) const
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{
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return const_iterator(objects.end());
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}
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iterator begin(void)
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{
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return iterator(objects.begin());
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}
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iterator end(void)
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{
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return iterator(objects.end());
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}
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ordered_iterator ordered_begin(void) const
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{
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if (!empty())
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return ordered_iterator(q_.top(), this, indirect_cmp(q_.value_comp()));
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else
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return ordered_end();
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}
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ordered_iterator ordered_end(void) const
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{
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return ordered_iterator(objects.end(), this, indirect_cmp(q_.value_comp()));
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}
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static handle_type s_handle_from_iterator(iterator const & it)
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{
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return handle_type(it.get_list_iterator());
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}
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value_compare const & value_comp(void) const
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{
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return q_.value_comp();
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}
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void reserve (size_type element_count)
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{
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q_.reserve(element_count);
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}
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};
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} /* namespace detail */
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} /* namespace heap */
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} /* namespace boost */
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#endif /* BOOST_HEAP_DETAIL_MUTABLE_HEAP_HPP */
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