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
alpar@100: ///\brief Classes for representing heaps.
alpar@100: ///
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 {
alpar@100:   namespace concepts {
alpar@100:     /// \addtogroup concept
alpar@100:     /// @{
alpar@100: 
alpar@100: 
alpar@100:     /// \brief A concept structure describes the main interface of heaps.
alpar@100:     ///
alpar@100:     /// A concept structure describes the main interface of heaps.
alpar@100:     ///
alpar@100:     template <typename Prio, typename ItemIntMap>
alpar@100:     class Heap {
alpar@100:     public:
alpar@100: 
alpar@100:       ///\brief Type of the items stored in the heap.
alpar@100:       typedef typename ItemIntMap::Key  Item;
alpar@100:   
alpar@100: 
alpar@100:       /// \brief Type to represent the items states.
alpar@100:       ///
alpar@100:       /// Each Item element have a state associated to it. It may be "in heap",
alpar@100:       /// "pre heap" or "post heap". The later two are indifferent from the
alpar@100:       /// heap's point of view, but may be useful to the user.
alpar@100:       ///
alpar@100:       /// The ItemIntMap _should_ be initialized in such way, that it maps
alpar@100:       /// PRE_HEAP (-1) to any element to be put in the heap...
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.
alpar@100:       /// \param _iim should be given to the constructor, since it is used
alpar@100:       /// internally to handle the cross references. The value of the map
alpar@100:       /// should be PRE_HEAP (-1) for each element.
alpar@100:       explicit Heap(ItemIntMap &_iim) {}
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: 
alpar@100:       /// \brief Checks if the heap stores no items.
alpar@100:       ///
alpar@100:       /// Returns \c true if and only if the heap stores no items.
alpar@100:       bool empty() const { return false; }
alpar@100: 
alpar@100:       /// \brief Makes empty this heap.
alpar@100:       ///
alpar@100:       /// Makes this heap empty.
alpar@100:       void clear();
alpar@100: 
alpar@100:       /// \brief Insert an item into the heap with the given heap.
alpar@100:       ///    
alpar@100:       /// Adds \c i to the heap with priority \c p. 
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: 
alpar@100:       /// \brief Returns the item with minimum priority.
alpar@100:       ///
alpar@100:       /// This method returns the item with minimum priority.  
alpar@100:       /// \pre The heap must be nonempty.  
alpar@100:       Item top() const {}
alpar@100: 
alpar@100:       /// \brief Returns the minimum priority.
alpar@100:       ///
alpar@100:       /// It returns the minimum priority.
alpar@100:       /// \pre The heap must be nonempty.
alpar@100:       Prio prio() const {}
alpar@100: 
alpar@100:       /// \brief Deletes the item with minimum priority.
alpar@100:       ///
alpar@100:       /// This method deletes the item with minimum priority.
alpar@100:       /// \pre The heap must be non-empty.  
alpar@100:       void pop() {}
alpar@100: 
alpar@100:       /// \brief Deletes \c i from the heap.
alpar@100:       ///
alpar@100:       /// This method deletes item \c i from the heap, if \c i was
alpar@100:       /// already stored in the heap.
alpar@100:       /// \param i The item to erase. 
alpar@100:       void erase(const Item &i) {}
alpar@100: 
alpar@100:       /// \brief Returns the priority of \c i.
alpar@100:       ///
alpar@100:       /// This function returns the priority of item \c i.  
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: 
alpar@100:       /// \brief \c i gets to the heap with priority \c p independently 
alpar@100:       /// if \c i was already there.
alpar@100:       ///
alpar@100:       /// This method calls \ref push(\c i, \c p) if \c i is not stored
alpar@100:       /// in the heap and sets the priority of \c i to \c p otherwise.
alpar@100:       /// It may throw an \e 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:       
alpar@100:       /// \brief Decreases the priority of \c i to \c p.
alpar@100:       ///
alpar@100:       /// This method decreases the priority of item \c i to \c p.
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: 
alpar@100:       /// \brief Increases the priority of \c i to \c p.
alpar@100:       ///
alpar@100:       /// This method sets the priority of item \c i to \c p. 
alpar@100:       /// \pre \c i must be stored in the heap with priority at most \c
alpar@100:       /// p relative to \c Compare.
alpar@100:       /// \param i The item.
alpar@100:       /// \param p The priority.
alpar@100:       void increase(const Item &i, const Prio &p) {}
alpar@100: 
alpar@100:       /// \brief Returns if \c item is in, has already been in, or has 
alpar@100:       /// never been in the heap.
alpar@100:       ///
alpar@100:       /// This method returns PRE_HEAP if \c item has never been in the
alpar@100:       /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
alpar@100:       /// otherwise. In the latter case it is possible that \c item will
alpar@100:       /// get back to the heap again.
alpar@100:       /// \param i The item.
alpar@100:       State state(const Item &i) const {}
alpar@100: 
alpar@100:       /// \brief Sets the state of the \c item in the heap.
alpar@100:       ///
alpar@100:       /// Sets the state of the \c item in the heap. It can be used to
alpar@100:       /// manually clear the heap when it is important to achive the
alpar@100:       /// better time complexity.
alpar@100:       /// \param i The item.
alpar@100:       /// \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:     
alpar@100: 	void constraints() {
alpar@100: 	  Item item;
alpar@100: 	  Prio prio;
alpar@100: 
alpar@100: 	  item=Item();
alpar@100: 	  prio=Prio();
alpar@100: 
alpar@100: 	  ignore_unused_variable_warning(item);
alpar@100: 	  ignore_unused_variable_warning(prio);
alpar@100: 
alpar@100: 	  typedef typename _Heap::State State;
alpar@100: 	  State state;
alpar@100: 
alpar@100: 	  ignore_unused_variable_warning(state);
alpar@100:       
alpar@100: 	  _Heap heap1 = _Heap(map);
alpar@100: 
alpar@100: 	  ignore_unused_variable_warning(heap1);
alpar@100:       
alpar@100: 	  heap.push(item, prio);
alpar@100: 
alpar@100: 	  prio = heap.prio();
alpar@100: 	  item = heap.top();
alpar@100: 
alpar@100: 	  heap.pop();
alpar@100: 
alpar@100: 	  heap.set(item, prio);
alpar@100: 	  heap.decrease(item, prio);
alpar@100: 	  heap.increase(item, prio);
alpar@100: 	  prio = heap[item];
alpar@100: 
alpar@100: 	  heap.erase(item);
alpar@100: 
alpar@100: 	  state = heap.state(item);
alpar@100: 
alpar@100: 	  state = _Heap::PRE_HEAP;
alpar@100: 	  state = _Heap::IN_HEAP;
alpar@100: 	  state = _Heap::POST_HEAP;
alpar@100: 
alpar@100: 	  heap.clear();
alpar@100: 	}
alpar@100:     
alpar@100: 	_Heap& heap;
alpar@100: 	ItemIntMap& map;
alpar@100: 
alpar@100: 	Constraints() : heap(0), map(0) {}
alpar@100:       };
alpar@100:     };
alpar@100: 
alpar@100:     /// @}
alpar@100:   } // namespace lemon
alpar@100: }
alpar@100: #endif // LEMON_CONCEPT_PATH_H