136 lines
4.3 KiB
C++
136 lines
4.3 KiB
C++
//
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//=======================================================================
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// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
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// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
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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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//=======================================================================
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//
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#ifndef BOOST_MUTABLE_QUEUE_HPP
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#define BOOST_MUTABLE_QUEUE_HPP
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#include <vector>
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#include <algorithm>
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#include <functional>
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#include <boost/property_map/property_map.hpp>
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#include <boost/pending/mutable_heap.hpp>
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#include <boost/pending/is_heap.hpp>
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#include <boost/graph/detail/array_binary_tree.hpp>
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#include <iterator>
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namespace boost {
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// The mutable queue whose elements are indexed
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//
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// This adaptor provides a special kind of priority queue that has
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// and update operation. This allows the ordering of the items to
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// change. After the ordering criteria for item x changes, one must
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// call the Q.update(x)
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//
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// In order to efficiently find x in the queue, a functor must be
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// provided to map value_type to a unique ID, which the
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// mutable_queue will then use to map to the location of the
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// item. The ID's generated must be between 0 and N, where N is the
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// value passed to the constructor of mutable_queue
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template <class IndexedType,
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class RandomAccessContainer = std::vector<IndexedType>,
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class Comp = std::less<typename RandomAccessContainer::value_type>,
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class ID = identity_property_map >
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class mutable_queue {
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public:
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typedef IndexedType value_type;
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typedef typename RandomAccessContainer::size_type size_type;
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protected:
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typedef typename RandomAccessContainer::iterator iterator;
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#if !defined BOOST_NO_STD_ITERATOR_TRAITS
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typedef array_binary_tree_node<iterator, ID> Node;
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#else
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typedef array_binary_tree_node<iterator, value_type, ID> Node;
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#endif
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typedef compare_array_node<RandomAccessContainer,Comp> Compare;
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typedef std::vector<size_type> IndexArray;
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public:
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typedef Compare value_compare;
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typedef ID id_generator;
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mutable_queue(size_type n, const Comp& x, const ID& _id)
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: index_array(n), comp(x), id(_id) {
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c.reserve(n);
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}
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template <class ForwardIterator>
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mutable_queue(ForwardIterator first, ForwardIterator last,
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const Comp& x, const ID& _id)
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: index_array(std::distance(first, last)), comp(x), id(_id)
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{
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while( first != last ) {
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push(*first);
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++first;
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}
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}
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bool empty() const { return c.empty(); }
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void pop() {
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value_type tmp = c.back();
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c.back() = c.front();
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c.front() = tmp;
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size_type id_f = get(id, c.back());
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size_type id_b = get(id, tmp);
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size_type i = index_array[ id_b ];
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index_array[ id_b ] = index_array[ id_f ];
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index_array[ id_f ] = i;
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c.pop_back();
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Node node(c.begin(), c.end(), c.begin(), id);
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down_heap(node, comp, index_array);
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}
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void push(const IndexedType& x) {
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c.push_back(x);
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/*set index-array*/
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index_array[ get(id, x) ] = c.size()-1;
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Node node(c.begin(), c.end(), c.end() - 1, id);
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up_heap(node, comp, index_array);
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}
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void update(const IndexedType& x) {
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size_type current_pos = index_array[ get(id, x) ];
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c[current_pos] = x;
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Node node(c.begin(), c.end(), c.begin()+current_pos, id);
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update_heap(node, comp, index_array);
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}
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value_type& front() { return c.front(); }
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value_type& top() { return c.front(); }
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const value_type& front() const { return c.front(); }
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const value_type& top() const { return c.front(); }
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size_type size() const { return c.size(); }
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void clear() { c.clear(); }
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#if 0
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// dwa 2003/7/11 - I don't know what compiler is supposed to
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// be able to compile this, but is_heap is not standard!!
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bool test() {
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return std::is_heap(c.begin(), c.end(), Comp());
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}
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#endif
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protected:
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IndexArray index_array;
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Compare comp;
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RandomAccessContainer c;
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ID id;
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};
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}
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#endif // BOOST_MUTABLE_QUEUE_HPP
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