deba@1330: /* -*- C++ -*-
deba@1330:  * src/lemon/concept/heap.h - Part of LEMON, a generic C++ optimization library
deba@1330:  *
deba@1330:  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@1359:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@1330:  *
deba@1330:  * Permission to use, modify and distribute this software is granted
deba@1330:  * provided that this copyright notice appears in all copies. For
deba@1330:  * precise terms see the accompanying LICENSE file.
deba@1330:  *
deba@1330:  * This software is provided "AS IS" with no warranty of any kind,
deba@1330:  * express or implied, and with no claim as to its suitability for any
deba@1330:  * purpose.
deba@1330:  *
deba@1330:  */
deba@1330: 
deba@1330: ///\ingroup concept
deba@1330: ///\file
deba@1330: ///\brief Classes for representing heaps.
deba@1330: ///
deba@1330: 
deba@1330: #ifndef LEMON_CONCEPT_HEAP_H
deba@1330: #define LEMON_CONCEPT_HEAP_H
deba@1330: 
deba@1330: #include <lemon/invalid.h>
deba@1330: 
deba@1330: namespace lemon {
deba@1330:   namespace concept {
deba@1330:     /// \addtogroup concept
deba@1330:     /// @{
deba@1330: 
deba@1330: 
deba@1330:     /// \brief A concept structure describes the main interface of heaps.
deba@1330:     ///
deba@1330:     /// A concept structure describes the main interface of heaps.
deba@1330:     ///
deba@1330:     template <typename Item, typename Prio, typename ItemIntMap>
deba@1330:     class Heap {
deba@1330:     public:
deba@1330:   
deba@1330: 
deba@1330:       /// \brief Type to represent the items states.
deba@1330:       ///
deba@1330:       /// Each Item element have a state associated to it. It may be "in heap",
deba@1330:       /// "pre heap" or "post heap". The later two are indifferent from the
deba@1330:       /// heap's point of view, but may be useful to the user.
deba@1330:       ///
deba@1330:       /// The ItemIntMap _should_ be initialized in such way, that it maps
deba@1330:       /// PRE_HEAP (-1) to any element to be put in the heap...
deba@1330:       enum state_enum {
deba@1330: 	IN_HEAP = 0,
deba@1330: 	PRE_HEAP = -1,
deba@1330: 	POST_HEAP = -2
deba@1330:       };
deba@1330:       
deba@1330:       /// \brief The constructor.
deba@1330:       ///
deba@1330:       /// The constructor.
deba@1330:       /// \param _iim should be given to the constructor, since it is used
deba@1330:       /// internally to handle the cross references. The value of the map
deba@1330:       /// should be PRE_HEAP (-1) for each element.
deba@1330:       explicit Heap(ItemIntMap &_iim) {}
deba@1330: 
deba@1330:       /// The number of items stored in the heap.
deba@1330:       ///
deba@1330:       /// \brief Returns the number of items stored in the heap.
deba@1330:       int size() const { return 0; }
deba@1330:       /// \brief Checks if the heap stores no items.
deba@1330:       ///
deba@1330:       /// Returns \c true if and only if the heap stores no items.
deba@1330:       bool empty() const { return false; }
deba@1330: 
deba@1330:       /// \brief Insert an item into the heap with the given heap.
deba@1330:       ///    
deba@1330:       /// Adds \c i to the heap with priority \c p. 
deba@1330:       /// \param i The item to insert.
deba@1330:       /// \param p The priority of the item.
deba@1330:       void push(const Item &i, const Prio &p) {}
deba@1330: 
deba@1330:       /// \brief Returns the item with minimum priority.
deba@1330:       ///
deba@1330:       /// This method returns the item with minimum priority.  
deba@1330:       /// \pre The heap must be nonempty.  
deba@1330:       Item top() const {}
deba@1330: 
deba@1330:       /// \brief Returns the minimum priority.
deba@1330:       ///
deba@1330:       /// It returns the minimum priority.
deba@1330:       /// \pre The heap must be nonempty.
deba@1330:       Prio prio() const {}
deba@1330: 
deba@1330:       /// \brief Deletes the item with minimum priority.
deba@1330:       ///
deba@1330:       /// This method deletes the item with minimum priority.
deba@1330:       /// \pre The heap must be non-empty.  
deba@1330:       void pop() {}
deba@1330: 
deba@1330:       /// \brief Deletes \c i from the heap.
deba@1330:       ///
deba@1330:       /// This method deletes item \c i from the heap, if \c i was
deba@1330:       /// already stored in the heap.
deba@1330:       /// \param i The item to erase. 
deba@1330:       void erase(const Item &i) {}
deba@1330: 
deba@1330:       /// \brief Returns the priority of \c i.
deba@1330:       ///
deba@1330:       /// This function returns the priority of item \c i.  
deba@1330:       /// \pre \c i must be in the heap.
deba@1330:       /// \param i The item.
deba@1330:       Prio operator[](const Item &i) const {}
deba@1330: 
deba@1330:       /// \brief \c i gets to the heap with priority \c p independently 
deba@1330:       /// if \c i was already there.
deba@1330:       ///
deba@1330:       /// This method calls \ref push(\c i, \c p) if \c i is not stored
deba@1330:       /// in the heap and sets the priority of \c i to \c p otherwise.
deba@1330:       /// It may throw an \e UnderFlowPriorityException. 
deba@1330:       /// \param i The item.
deba@1330:       /// \param p The priority.
deba@1330:       void set(const Item &i, const Prio &p) {}
deba@1330:       
deba@1330:       /// \brief Decreases the priority of \c i to \c p.
deba@1330:       ///
deba@1330:       /// This method decreases the priority of item \c i to \c p.
deba@1330:       /// \pre \c i must be stored in the heap with priority at least \c p.
deba@1330:       /// \param i The item.
deba@1330:       /// \param p The priority.
deba@1330:       void decrease(const Item &i, const Prio &p) {}
deba@1330: 
deba@1330:       /// \brief Increases the priority of \c i to \c p.
deba@1330:       ///
deba@1330:       /// This method sets the priority of item \c i to \c p. 
deba@1330:       /// \pre \c i must be stored in the heap with priority at most \c
deba@1330:       /// p relative to \c Compare.
deba@1330:       /// \param i The item.
deba@1330:       /// \param p The priority.
deba@1330:       void increase(const Item &i, const Prio &p) {}
deba@1330: 
deba@1330:       /// \brief Returns if \c item is in, has already been in, or has 
deba@1330:       /// never been in the heap.
deba@1330:       ///
deba@1330:       /// This method returns PRE_HEAP if \c item has never been in the
deba@1330:       /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
deba@1330:       /// otherwise. In the latter case it is possible that \c item will
deba@1330:       /// get back to the heap again.
deba@1330:       /// \param i The item.
deba@1330:       state_enum state(const Item &i) const {}
deba@1330: 
deba@1330: 
deba@1330:       template <typename _Heap>
deba@1330:       struct Constraints {
deba@1330:       public:
deba@1330:     
deba@1330: 	void constraints() {
deba@1330: 	  Item item;
deba@1330: 	  Prio prio;
deba@1330: 
deba@1330: 	  ignore_unused_variable_warning(item);
deba@1330: 	  ignore_unused_variable_warning(prio);
deba@1330: 
deba@1330: 	  typedef typename _Heap::state_enum state_enum;
deba@1330: 	  state_enum state;
deba@1330: 
deba@1330: 	  ignore_unused_variable_warning(state);
deba@1330:       
deba@1330: 	  _Heap heap1 = _Heap(map);
deba@1330: 
deba@1330: 	  ignore_unused_variable_warning(heap1);
deba@1330:       
deba@1330: 	  heap.push(item, prio);
deba@1330: 
deba@1330: 	  prio = heap.prio();
deba@1330: 	  item = heap.top();
deba@1330: 
deba@1330: 	  heap.pop();
deba@1330: 
deba@1330: 	  heap.set(item, prio);
deba@1330: 	  heap.decrease(item, prio);
deba@1330: 	  heap.increase(item, prio);
deba@1330: 	  prio = heap[item];
deba@1330: 
deba@1330: 	  heap.erase(item);
deba@1330: 
deba@1330: 	  state = heap.state(item);
deba@1330: 
deba@1330: 	  state = _Heap::PRE_HEAP;
deba@1330: 	  state = _Heap::IN_HEAP;
deba@1330: 	  state = _Heap::POST_HEAP;
deba@1330: 	}
deba@1330:     
deba@1330: 	_Heap& heap;
deba@1330: 	ItemIntMap& map;
deba@1330: 
deba@1330: 	Constraints() : heap(0), map(0) {}
deba@1330:       };
deba@1330:     };
deba@1330: 
deba@1330:     /// @}
deba@1330:   } // namespace lemon
deba@1330: }
deba@1330: #endif // LEMON_CONCEPT_PATH_H