/* -*- mode: C++; indent-tabs-mode: nil; -*- * * This file is a part of LEMON, a generic C++ optimization library. * * Copyright (C) 2003-2009 * 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. * */ ///\ingroup concept ///\file ///\brief The concept of heaps. #ifndef LEMON_CONCEPTS_HEAP_H #define LEMON_CONCEPTS_HEAP_H #include #include namespace lemon { namespace concepts { /// \addtogroup concept /// @{ /// \brief The heap concept. /// /// Concept class describing the main interface of heaps. 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. In a heap one can change the priority of an /// item, add or erase an item, etc. /// /// \tparam PR Type of the priority of the items. /// \tparam IM A read and writable item map with int values, used /// internally to handle the cross references. /// \tparam Comp A functor class for the ordering of the priorities. /// The default is \c std::less. #ifdef DOXYGEN template > #else template #endif class Heap { public: /// Type of the item-int map. typedef IM ItemIntMap; /// Type of the priorities. typedef PR Prio; /// Type of the items stored in the heap. typedef typename ItemIntMap::Key Item; /// \brief Type to represent the states of the items. /// /// Each item has a state associated to it. It can be "in heap", /// "pre heap" or "post heap". The later two are indifferent /// from the point of view of the heap, but may be useful for /// the user. /// /// The item-int map must be initialized in such way that it assigns /// \c PRE_HEAP (-1) to any element to be put in the heap. enum State { IN_HEAP = 0, ///< The "in heap" state constant. PRE_HEAP = -1, ///< The "pre heap" state constant. POST_HEAP = -2 ///< The "post heap" state constant. }; /// \brief The constructor. /// /// The constructor. /// \param map A map that assigns \c int values to keys of type /// \c Item. It is used internally by the heap implementations to /// handle the cross references. The assigned value must be /// \c PRE_HEAP (-1) for every item. explicit Heap(ItemIntMap &map) {} /// \brief The number of items stored in the heap. /// /// Returns the number of items stored in the heap. int size() const { return 0; } /// \brief Checks if the heap is empty. /// /// Returns \c true if the heap is empty. bool empty() const { return false; } /// \brief Makes the heap empty. /// /// Makes the heap empty. void clear(); /// \brief Inserts an item into the heap with the given priority. /// /// Inserts the given item into the heap with the given priority. /// \param i The item to insert. /// \param p The priority of the item. void push(const Item &i, const Prio &p) {} /// \brief Returns the item having minimum priority. /// /// Returns the item having minimum priority. /// \pre The heap must be non-empty. Item top() const {} /// \brief The minimum priority. /// /// Returns the minimum priority. /// \pre The heap must be non-empty. Prio prio() const {} /// \brief Removes the item having minimum priority. /// /// Removes the item having minimum priority. /// \pre The heap must be non-empty. void pop() {} /// \brief Removes an item from the heap. /// /// Removes the given item from the heap if it is already stored. /// \param i The item to delete. void erase(const Item &i) {} /// \brief The priority of an item. /// /// Returns the priority of the given item. /// \param i The item. /// \pre \c i must be in the heap. Prio operator[](const Item &i) const {} /// \brief Sets the priority of an item or inserts it, if it is /// not stored in the heap. /// /// This method sets the priority of the given item if it is /// already stored in the heap. /// Otherwise it inserts the given item with the given priority. /// /// \param i The item. /// \param p The priority. void set(const Item &i, const Prio &p) {} /// \brief Decreases the priority of an item to the given value. /// /// Decreases the priority of an item to the given value. /// \param i The item. /// \param p The priority. /// \pre \c i must be stored in the heap with priority at least \c p. void decrease(const Item &i, const Prio &p) {} /// \brief Increases the priority of an item to the given value. /// /// Increases the priority of an item to the given value. /// \param i The item. /// \param p The priority. /// \pre \c i must be stored in the heap with priority at most \c p. void increase(const Item &i, const Prio &p) {} /// \brief Returns if an item is in, has already been in, or has /// never been in the heap. /// /// This method returns \c PRE_HEAP if the given item has never /// been in the heap, \c IN_HEAP if it is in the heap at the moment, /// and \c POST_HEAP otherwise. /// In the latter case it is possible that the item will get back /// to the heap again. /// \param i The item. State state(const Item &i) const {} /// \brief Sets the state of an item in the heap. /// /// Sets the state of the given 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) {} template struct Constraints { public: void constraints() { typedef typename _Heap::Item OwnItem; typedef typename _Heap::Prio OwnPrio; typedef typename _Heap::State OwnState; Item item; Prio prio; item=Item(); prio=Prio(); ignore_unused_variable_warning(item); ignore_unused_variable_warning(prio); OwnItem own_item; OwnPrio own_prio; OwnState own_state; own_item=Item(); own_prio=Prio(); ignore_unused_variable_warning(own_item); ignore_unused_variable_warning(own_prio); ignore_unused_variable_warning(own_state); _Heap heap1(map); _Heap heap2 = heap1; ignore_unused_variable_warning(heap1); ignore_unused_variable_warning(heap2); int s = heap.size(); ignore_unused_variable_warning(s); bool e = heap.empty(); ignore_unused_variable_warning(e); prio = heap.prio(); item = heap.top(); prio = heap[item]; own_prio = heap.prio(); own_item = heap.top(); own_prio = heap[own_item]; heap.push(item, prio); heap.push(own_item, own_prio); heap.pop(); heap.set(item, prio); heap.decrease(item, prio); heap.increase(item, prio); heap.set(own_item, own_prio); heap.decrease(own_item, own_prio); heap.increase(own_item, own_prio); heap.erase(item); heap.erase(own_item); heap.clear(); own_state = heap.state(own_item); heap.state(own_item, own_state); own_state = _Heap::PRE_HEAP; own_state = _Heap::IN_HEAP; own_state = _Heap::POST_HEAP; } _Heap& heap; ItemIntMap& map; }; }; /// @} } // namespace lemon } #endif