alpar@100: /* -*- C++ -*-
alpar@100:  *
alpar@100:  * This file is a part of LEMON, a generic C++ optimization library
alpar@100:  *
alpar@100:  * Copyright (C) 2003-2008
alpar@100:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@100:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
alpar@100:  *
alpar@100:  * Permission to use, modify and distribute this software is granted
alpar@100:  * provided that this copyright notice appears in all copies. For
alpar@100:  * precise terms see the accompanying LICENSE file.
alpar@100:  *
alpar@100:  * This software is provided "AS IS" with no warranty of any kind,
alpar@100:  * express or implied, and with no claim as to its suitability for any
alpar@100:  * purpose.
alpar@100:  *
alpar@100:  */
alpar@100: 
alpar@100: ///\ingroup concept
alpar@100: ///\file
kpeter@113: ///\brief The concept of heaps.
alpar@100: 
alpar@100: #ifndef LEMON_CONCEPT_HEAP_H
alpar@100: #define LEMON_CONCEPT_HEAP_H
alpar@100: 
alpar@100: #include <lemon/bits/invalid.h>
alpar@100: 
alpar@100: namespace lemon {
kpeter@113: 
alpar@100:   namespace concepts {
kpeter@113: 
alpar@100:     /// \addtogroup concept
alpar@100:     /// @{
alpar@100: 
kpeter@113:     /// \brief The heap concept.
alpar@100:     ///
kpeter@113:     /// Concept class describing the main interface of heaps.
kpeter@113:     template <typename Priority, typename ItemIntMap>
alpar@100:     class Heap {
alpar@100:     public:
alpar@100: 
kpeter@113:       /// Type of the items stored in the heap.
kpeter@113:       typedef typename ItemIntMap::Key Item;
alpar@100: 
kpeter@113:       /// Type of the priorities.
kpeter@113:       typedef Priority Prio;
kpeter@113: 
kpeter@113:       /// \brief Type to represent the states of the items.
alpar@100:       ///
kpeter@113:       /// Each item has a state associated to it. It can be "in heap",
kpeter@113:       /// "pre heap" or "post heap". The later two are indifferent
kpeter@113:       /// from the point of view of the heap, but may be useful for
kpeter@113:       /// the user.
alpar@100:       ///
kpeter@113:       /// The \c ItemIntMap must be initialized in such a way, that it 
kpeter@113:       /// assigns \c PRE_HEAP (<tt>-1</tt>) to every item.
alpar@100:       enum State {
alpar@100: 	IN_HEAP = 0,
alpar@100: 	PRE_HEAP = -1,
alpar@100: 	POST_HEAP = -2
alpar@100:       };
alpar@100:       
alpar@100:       /// \brief The constructor.
alpar@100:       ///
alpar@100:       /// The constructor.
kpeter@113:       /// \param map A map that assigns \c int values to keys of type
kpeter@113:       /// \c Item. It is used internally by the heap implementations to
kpeter@113:       /// handle the cross references. The assigned value must be
kpeter@113:       /// \c PRE_HEAP (<tt>-1</tt>) for every item.
kpeter@113:       explicit Heap(ItemIntMap &map) {}
alpar@100: 
alpar@100:       /// \brief The number of items stored in the heap.
alpar@100:       ///
alpar@100:       /// Returns the number of items stored in the heap.
alpar@100:       int size() const { return 0; }
alpar@100: 
kpeter@113:       /// \brief Checks if the heap is empty.
alpar@100:       ///
kpeter@113:       /// Returns \c true if the heap is empty.
alpar@100:       bool empty() const { return false; }
alpar@100: 
kpeter@113:       /// \brief Makes the heap empty.
alpar@100:       ///
kpeter@113:       /// Makes the heap empty.
alpar@100:       void clear();
alpar@100: 
kpeter@113:       /// \brief Inserts an item into the heap with the given priority.
alpar@100:       ///    
kpeter@113:       /// Inserts the given item into the heap with the given priority. 
alpar@100:       /// \param i The item to insert.
alpar@100:       /// \param p The priority of the item.
alpar@100:       void push(const Item &i, const Prio &p) {}
alpar@100: 
kpeter@113:       /// \brief Returns the item having minimum priority.
alpar@100:       ///
kpeter@113:       /// Returns the item having minimum priority.
kpeter@113:       /// \pre The heap must be non-empty.
alpar@100:       Item top() const {}
alpar@100: 
kpeter@113:       /// \brief The minimum priority.
alpar@100:       ///
kpeter@113:       /// Returns the minimum priority.
kpeter@113:       /// \pre The heap must be non-empty.
alpar@100:       Prio prio() const {}
alpar@100: 
kpeter@113:       /// \brief Removes the item having minimum priority.
alpar@100:       ///
kpeter@113:       /// Removes the item having minimum priority.
kpeter@113:       /// \pre The heap must be non-empty.
alpar@100:       void pop() {}
alpar@100: 
kpeter@113:       /// \brief Removes an item from the heap.
alpar@100:       ///
kpeter@113:       /// Removes the given item from the heap if it is already stored.
kpeter@113:       /// \param i The item to delete. 
alpar@100:       void erase(const Item &i) {}
alpar@100: 
kpeter@113:       /// \brief The priority of an item.
alpar@100:       ///
kpeter@113:       /// Returns the priority of the given item.  
alpar@100:       /// \pre \c i must be in the heap.
alpar@100:       /// \param i The item.
alpar@100:       Prio operator[](const Item &i) const {}
alpar@100: 
kpeter@113:       /// \brief Sets the priority of an item or inserts it, if it is
kpeter@113:       /// not stored in the heap.
alpar@100:       ///
kpeter@113:       /// This method sets the priority of the given item if it is
kpeter@113:       /// already stored in the heap.
kpeter@113:       /// Otherwise it inserts the given item with the given priority.
kpeter@113:       ///
kpeter@113:       /// It may throw an \ref UnderflowPriorityException.
alpar@100:       /// \param i The item.
alpar@100:       /// \param p The priority.
alpar@100:       void set(const Item &i, const Prio &p) {}
alpar@100:       
kpeter@113:       /// \brief Decreases the priority of an item to the given value.
alpar@100:       ///
kpeter@113:       /// Decreases the priority of an item to the given value.
alpar@100:       /// \pre \c i must be stored in the heap with priority at least \c p.
alpar@100:       /// \param i The item.
alpar@100:       /// \param p The priority.
alpar@100:       void decrease(const Item &i, const Prio &p) {}
alpar@100: 
kpeter@113:       /// \brief Increases the priority of an item to the given value.
alpar@100:       ///
kpeter@113:       /// Increases the priority of an item to the given value.
kpeter@113:       /// \pre \c i must be stored in the heap with priority at most \c p.
alpar@100:       /// \param i The item.
alpar@100:       /// \param p The priority.
alpar@100:       void increase(const Item &i, const Prio &p) {}
alpar@100: 
kpeter@113:       /// \brief Returns if an item is in, has already been in, or has
alpar@100:       /// never been in the heap.
alpar@100:       ///
kpeter@113:       /// This method returns \c PRE_HEAP if the given item has never
kpeter@113:       /// been in the heap, \c IN_HEAP if it is in the heap at the moment,
kpeter@113:       /// and \c POST_HEAP otherwise.
kpeter@113:       /// In the latter case it is possible that the item will get back
kpeter@113:       /// to the heap again.
alpar@100:       /// \param i The item.
alpar@100:       State state(const Item &i) const {}
alpar@100: 
kpeter@113:       /// \brief Sets the state of an item in the heap.
alpar@100:       ///
kpeter@113:       /// Sets the state of the given item in the heap. It can be used
kpeter@113:       /// to manually clear the heap when it is important to achive the
alpar@100:       /// better time complexity.
alpar@100:       /// \param i The item.
kpeter@113:       /// \param st The state. It should not be \c IN_HEAP.
alpar@100:       void state(const Item& i, State st) {}
alpar@100: 
alpar@100: 
alpar@100:       template <typename _Heap>
alpar@100:       struct Constraints {
alpar@100:       public:
alpar@100: 	void constraints() {
kpeter@113: 	  typedef typename _Heap::Item OwnItem;
kpeter@113: 	  typedef typename _Heap::Prio OwnPrio;
kpeter@113: 	  typedef typename _Heap::State OwnState;
kpeter@113: 
alpar@100: 	  Item item;
alpar@100: 	  Prio prio;
kpeter@113: 	  State state;
alpar@100: 	  item=Item();
alpar@100: 	  prio=Prio();
alpar@100: 	  ignore_unused_variable_warning(item);
alpar@100: 	  ignore_unused_variable_warning(prio);
kpeter@113: 	  ignore_unused_variable_warning(state);
alpar@100: 
kpeter@113: 	  OwnItem own_item;
kpeter@113: 	  OwnPrio own_prio;
kpeter@113: 	  OwnState own_state;
kpeter@113: 	  own_item=Item();
kpeter@113: 	  own_prio=Prio();
kpeter@113: 	  ignore_unused_variable_warning(own_item);
kpeter@113: 	  ignore_unused_variable_warning(own_prio);
kpeter@113: 	  ignore_unused_variable_warning(own_state);
alpar@100: 
kpeter@113: 	  _Heap heap1(map);
kpeter@113: 	  _Heap heap2 = heap1;
alpar@100: 	  ignore_unused_variable_warning(heap1);
kpeter@113: 	  ignore_unused_variable_warning(heap2);
kpeter@113: 	  
kpeter@113: 	  int s = heap.size();
kpeter@113: 	  bool e = heap.empty();
alpar@100: 
alpar@100: 	  prio = heap.prio();
alpar@100: 	  item = heap.top();
kpeter@113: 	  prio = heap[item];
kpeter@113: 	  own_prio = heap.prio();
kpeter@113: 	  own_item = heap.top();
kpeter@113: 	  own_prio = heap[own_item];
alpar@100: 
kpeter@113: 	  heap.push(item, prio);
kpeter@113: 	  heap.push(own_item, own_prio);
alpar@100: 	  heap.pop();
alpar@100: 
alpar@100: 	  heap.set(item, prio);
alpar@100: 	  heap.decrease(item, prio);
alpar@100: 	  heap.increase(item, prio);
kpeter@113: 	  heap.set(own_item, own_prio);
kpeter@113: 	  heap.decrease(own_item, own_prio);
kpeter@113: 	  heap.increase(own_item, own_prio);
alpar@100: 
alpar@100: 	  heap.erase(item);
kpeter@113: 	  heap.erase(own_item);
kpeter@113: 	  heap.clear();
alpar@100: 
alpar@100: 	  state = heap.state(item);
kpeter@113: 	  heap.state(item, state);
kpeter@113: 	  state = heap.state(own_item);
kpeter@113: 	  heap.state(own_item, own_state);
alpar@100: 
alpar@100: 	  state = _Heap::PRE_HEAP;
alpar@100: 	  state = _Heap::IN_HEAP;
alpar@100: 	  state = _Heap::POST_HEAP;
kpeter@113: 	  own_state = _Heap::PRE_HEAP;
kpeter@113: 	  own_state = _Heap::IN_HEAP;
kpeter@113: 	  own_state = _Heap::POST_HEAP;
kpeter@113: 	}
alpar@100: 
alpar@100: 	_Heap& heap;
alpar@100: 	ItemIntMap& map;
alpar@100:       };
alpar@100:     };
alpar@100: 
alpar@100:     /// @}
alpar@100:   } // namespace lemon
alpar@100: }
alpar@100: #endif // LEMON_CONCEPT_PATH_H