lemon/concepts/heap.h
author alpar
Mon, 01 Oct 2007 18:55:58 +0000
changeset 2482 217123f59d7e
parent 2263 9273fe7d850c
child 2547 f393a8162688
permissions -rw-r--r--
Missing header file added.
     1 /* -*- C++ -*-
     2  *
     3  * This file is a part of LEMON, a generic C++ optimization library
     4  *
     5  * Copyright (C) 2003-2007
     6  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     7  * (Egervary Research Group on Combinatorial Optimization, EGRES).
     8  *
     9  * Permission to use, modify and distribute this software is granted
    10  * provided that this copyright notice appears in all copies. For
    11  * precise terms see the accompanying LICENSE file.
    12  *
    13  * This software is provided "AS IS" with no warranty of any kind,
    14  * express or implied, and with no claim as to its suitability for any
    15  * purpose.
    16  *
    17  */
    18 
    19 ///\ingroup concept
    20 ///\file
    21 ///\brief Classes for representing heaps.
    22 ///
    23 
    24 #ifndef LEMON_CONCEPT_HEAP_H
    25 #define LEMON_CONCEPT_HEAP_H
    26 
    27 #include <lemon/bits/invalid.h>
    28 
    29 namespace lemon {
    30   namespace concepts {
    31     /// \addtogroup concept
    32     /// @{
    33 
    34 
    35     /// \brief A concept structure describes the main interface of heaps.
    36     ///
    37     /// A concept structure describes the main interface of heaps.
    38     ///
    39     template <typename Prio, typename ItemIntMap>
    40     class Heap {
    41     public:
    42 
    43       ///\brief Type of the items stored in the heap.
    44       typedef typename ItemIntMap::Key  Item;
    45   
    46 
    47       /// \brief Type to represent the items states.
    48       ///
    49       /// Each Item element have a state associated to it. It may be "in heap",
    50       /// "pre heap" or "post heap". The later two are indifferent from the
    51       /// heap's point of view, but may be useful to the user.
    52       ///
    53       /// The ItemIntMap _should_ be initialized in such way, that it maps
    54       /// PRE_HEAP (-1) to any element to be put in the heap...
    55       enum state_enum {
    56 	IN_HEAP = 0,
    57 	PRE_HEAP = -1,
    58 	POST_HEAP = -2
    59       };
    60       
    61       /// \brief The constructor.
    62       ///
    63       /// The constructor.
    64       /// \param _iim should be given to the constructor, since it is used
    65       /// internally to handle the cross references. The value of the map
    66       /// should be PRE_HEAP (-1) for each element.
    67       explicit Heap(ItemIntMap &_iim) {}
    68 
    69       /// \brief The number of items stored in the heap.
    70       ///
    71       /// Returns the number of items stored in the heap.
    72       int size() const { return 0; }
    73 
    74       /// \brief Checks if the heap stores no items.
    75       ///
    76       /// Returns \c true if and only if the heap stores no items.
    77       bool empty() const { return false; }
    78 
    79       /// \brief Makes empty this heap.
    80       ///
    81       /// Makes this heap empty.
    82       void clear();
    83 
    84       /// \brief Insert an item into the heap with the given heap.
    85       ///    
    86       /// Adds \c i to the heap with priority \c p. 
    87       /// \param i The item to insert.
    88       /// \param p The priority of the item.
    89       void push(const Item &i, const Prio &p) {}
    90 
    91       /// \brief Returns the item with minimum priority.
    92       ///
    93       /// This method returns the item with minimum priority.  
    94       /// \pre The heap must be nonempty.  
    95       Item top() const {}
    96 
    97       /// \brief Returns the minimum priority.
    98       ///
    99       /// It returns the minimum priority.
   100       /// \pre The heap must be nonempty.
   101       Prio prio() const {}
   102 
   103       /// \brief Deletes the item with minimum priority.
   104       ///
   105       /// This method deletes the item with minimum priority.
   106       /// \pre The heap must be non-empty.  
   107       void pop() {}
   108 
   109       /// \brief Deletes \c i from the heap.
   110       ///
   111       /// This method deletes item \c i from the heap, if \c i was
   112       /// already stored in the heap.
   113       /// \param i The item to erase. 
   114       void erase(const Item &i) {}
   115 
   116       /// \brief Returns the priority of \c i.
   117       ///
   118       /// This function returns the priority of item \c i.  
   119       /// \pre \c i must be in the heap.
   120       /// \param i The item.
   121       Prio operator[](const Item &i) const {}
   122 
   123       /// \brief \c i gets to the heap with priority \c p independently 
   124       /// if \c i was already there.
   125       ///
   126       /// This method calls \ref push(\c i, \c p) if \c i is not stored
   127       /// in the heap and sets the priority of \c i to \c p otherwise.
   128       /// It may throw an \e UnderFlowPriorityException. 
   129       /// \param i The item.
   130       /// \param p The priority.
   131       void set(const Item &i, const Prio &p) {}
   132       
   133       /// \brief Decreases the priority of \c i to \c p.
   134       ///
   135       /// This method decreases the priority of item \c i to \c p.
   136       /// \pre \c i must be stored in the heap with priority at least \c p.
   137       /// \param i The item.
   138       /// \param p The priority.
   139       void decrease(const Item &i, const Prio &p) {}
   140 
   141       /// \brief Increases the priority of \c i to \c p.
   142       ///
   143       /// This method sets the priority of item \c i to \c p. 
   144       /// \pre \c i must be stored in the heap with priority at most \c
   145       /// p relative to \c Compare.
   146       /// \param i The item.
   147       /// \param p The priority.
   148       void increase(const Item &i, const Prio &p) {}
   149 
   150       /// \brief Returns if \c item is in, has already been in, or has 
   151       /// never been in the heap.
   152       ///
   153       /// This method returns PRE_HEAP if \c item has never been in the
   154       /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
   155       /// otherwise. In the latter case it is possible that \c item will
   156       /// get back to the heap again.
   157       /// \param i The item.
   158       state_enum state(const Item &i) const {}
   159 
   160       /// \brief Sets the state of the \c item in the heap.
   161       ///
   162       /// Sets the state of the \c item in the heap. It can be used to
   163       /// manually clear the heap when it is important to achive the
   164       /// better time complexity.
   165       /// \param i The item.
   166       /// \param st The state. It should not be \c IN_HEAP. 
   167       void state(const Item& i, state_enum st) {}
   168 
   169 
   170       template <typename _Heap>
   171       struct Constraints {
   172       public:
   173     
   174 	void constraints() {
   175 	  Item item;
   176 	  Prio prio;
   177 
   178 	  item=Item();
   179 	  prio=Prio();
   180 
   181 	  ignore_unused_variable_warning(item);
   182 	  ignore_unused_variable_warning(prio);
   183 
   184 	  typedef typename _Heap::state_enum state_enum;
   185 	  state_enum state;
   186 
   187 	  ignore_unused_variable_warning(state);
   188       
   189 	  _Heap heap1 = _Heap(map);
   190 
   191 	  ignore_unused_variable_warning(heap1);
   192       
   193 	  heap.push(item, prio);
   194 
   195 	  prio = heap.prio();
   196 	  item = heap.top();
   197 
   198 	  heap.pop();
   199 
   200 	  heap.set(item, prio);
   201 	  heap.decrease(item, prio);
   202 	  heap.increase(item, prio);
   203 	  prio = heap[item];
   204 
   205 	  heap.erase(item);
   206 
   207 	  state = heap.state(item);
   208 
   209 	  state = _Heap::PRE_HEAP;
   210 	  state = _Heap::IN_HEAP;
   211 	  state = _Heap::POST_HEAP;
   212 
   213 	  heap.clear();
   214 	}
   215     
   216 	_Heap& heap;
   217 	ItemIntMap& map;
   218 
   219 	Constraints() : heap(0), map(0) {}
   220       };
   221     };
   222 
   223     /// @}
   224   } // namespace lemon
   225 }
   226 #endif // LEMON_CONCEPT_PATH_H