diff --git a/lemon/kary_heap.h b/lemon/kary_heap.h new file mode 100644 --- /dev/null +++ b/lemon/kary_heap.h @@ -0,0 +1,342 @@ +/* -*- C++ -*- + * + * This file is a part of LEMON, a generic C++ optimization library + * + * Copyright (C) 2003-2008 + * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport + * (Egervary Research Group on Combinatorial Optimization, EGRES). + * + * Permission to use, modify and distribute this software is granted + * provided that this copyright notice appears in all copies. For + * precise terms see the accompanying LICENSE file. + * + * This software is provided "AS IS" with no warranty of any kind, + * express or implied, and with no claim as to its suitability for any + * purpose. + * + */ + +#ifndef LEMON_KARY_HEAP_H +#define LEMON_KARY_HEAP_H + +///\ingroup auxdat +///\file +///\brief Kary Heap implementation. + +#include +#include +#include +#include + +namespace lemon { + + ///\ingroup auxdat + /// + ///\brief A Kary Heap implementation. + /// + ///This class implements the \e Kary \e heap data structure. A \e heap + ///is a data structure for storing items with specified values called \e + ///priorities in such a way that finding the item with minimum priority is + ///efficient. \c Compare specifies the ordering of the priorities. In a heap + ///one can change the priority of an item, add or erase an item, etc. + /// + ///\param _Prio Type of the priority of the items. + ///\param _ItemIntMap A read and writable Item int map, used internally + ///to handle the cross references. + ///\param _Compare A class for the ordering of the priorities. The + ///default is \c std::less<_Prio>. + /// + ///\sa FibHeap + ///\sa Dijkstra + ///\author Dorian Batha + + template > + + class KaryHeap { + + public: + ///\e + typedef _ItemIntMap ItemIntMap; + ///\e + typedef _Prio Prio; + ///\e + typedef typename ItemIntMap::Key Item; + ///\e + typedef std::pair Pair; + ///\e + typedef _Compare Compare; + ///\e + + /// \brief Type to represent the items states. + /// + /// Each Item element have a state associated to it. It may be "in heap", + /// "pre heap" or "post heap". The latter two are indifferent from the + /// heap's point of view, but may be useful to the user. + /// + /// The ItemIntMap \e should be initialized in such way that it maps + /// PRE_HEAP (-1) to any element to be put in the heap... + enum State { + IN_HEAP = 0, + PRE_HEAP = -1, + POST_HEAP = -2 + }; + + private: + std::vector data; + Compare comp; + ItemIntMap &iim; + int K; + + public: + /// \brief The constructor. + /// + /// The constructor. + /// \param _iim should be given to the constructor, since it is used + /// internally to handle the cross references. The value of the map + /// should be PRE_HEAP (-1) for each element. + explicit KaryHeap(ItemIntMap &_iim, const int &_K=32) : iim(_iim), K(_K) {} + + /// \brief The constructor. + /// + /// The constructor. + /// \param _iim should be given to the constructor, since it is used + /// internally to handle the cross references. The value of the map + /// should be PRE_HEAP (-1) for each element. + /// + /// \param _comp The comparator function object. + KaryHeap(ItemIntMap &_iim, const Compare &_comp, const int &_K=32) + : iim(_iim), comp(_comp), K(_K) {} + + + /// The number of items stored in the heap. + /// + /// \brief Returns the number of items stored in the heap. + int size() const { return data.size(); } + + /// \brief Checks if the heap stores no items. + /// + /// Returns \c true if and only if the heap stores no items. + bool empty() const { return data.empty(); } + + /// \brief Make empty this heap. + /// + /// Make empty this heap. It does not change the cross reference map. + /// If you want to reuse what is not surely empty you should first clear + /// the heap and after that you should set the cross reference map for + /// each item to \c PRE_HEAP. + void clear() { data.clear(); } + + private: + int parent(int i) { return (i-1)/K; } + int first_child(int i) { return K*i+1; } + + bool less(const Pair &p1, const Pair &p2) const { + return comp(p1.second, p2.second); + } + + int find_min(const int child, const int length) { + int min=child, i=1; + while( i0 && less(p,data[par]) ) { + move(data[par],hole); + hole = par; + par = parent(hole); + } + move(p, hole); + } + + void bubble_down(int hole, Pair p, int length) { + if( length>1 ) { + int child = first_child(hole); + while( child0) bubble_down(0, data[n], n); + data.pop_back(); + } + + /// \brief Deletes \c i from the heap. + /// + /// This method deletes item \c i from the heap. + /// \param i The item to erase. + /// \pre The item should be in the heap. + void erase(const Item &i) { + int h = iim[i]; + int n = data.size()-1; + iim.set(data[h].first, POST_HEAP); + if( h=0) s=0; + return State(s); + } + + /// \brief Sets the state of the \c item in the heap. + /// + /// Sets the state of the \c item in the heap. It can be used to + /// manually clear the heap when it is important to achive the + /// better time complexity. + /// \param i The item. + /// \param st The state. It should not be \c IN_HEAP. + void state(const Item& i, State st) { + switch (st) { + case POST_HEAP: + case PRE_HEAP: + if (state(i) == IN_HEAP) erase(i); + iim[i] = st; + break; + case IN_HEAP: + break; + } + } + + /// \brief Replaces an item in the heap. + /// + /// The \c i item is replaced with \c j item. The \c i item should + /// be in the heap, while the \c j should be out of the heap. The + /// \c i item will out of the heap and \c j will be in the heap + /// with the same prioriority as prevoiusly the \c i item. + void replace(const Item& i, const Item& j) { + int idx=iim[i]; + iim.set(i, iim[j]); + iim.set(j, idx); + data[idx].first=j; + } + + }; // class KaryHeap + +} // namespace lemon + +#endif // LEMON_KARY_HEAP_H