COIN-OR::LEMON - Graph Library

source: lemon-1.0/lemon/concepts/heap.h @ 113:18a7ee8fa56e

Last change on this file since 113:18a7ee8fa56e was 113:18a7ee8fa56e, checked in by Peter Kovacs <kpeter@…>, 13 years ago

Improvements in the heap concept

  • Better concept checking.
  • Improved doc.
File size: 7.3 KB
RevLine 
[100]1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2008
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
[113]21///\brief The concept of heaps.
[100]22
23#ifndef LEMON_CONCEPT_HEAP_H
24#define LEMON_CONCEPT_HEAP_H
25
26#include <lemon/bits/invalid.h>
27
28namespace lemon {
[113]29
[100]30  namespace concepts {
[113]31
[100]32    /// \addtogroup concept
33    /// @{
34
[113]35    /// \brief The heap concept.
[100]36    ///
[113]37    /// Concept class describing the main interface of heaps.
38    template <typename Priority, typename ItemIntMap>
[100]39    class Heap {
40    public:
41
[113]42      /// Type of the items stored in the heap.
43      typedef typename ItemIntMap::Key Item;
[100]44
[113]45      /// Type of the priorities.
46      typedef Priority Prio;
47
48      /// \brief Type to represent the states of the items.
[100]49      ///
[113]50      /// Each item has a state associated to it. It can be "in heap",
51      /// "pre heap" or "post heap". The later two are indifferent
52      /// from the point of view of the heap, but may be useful for
53      /// the user.
[100]54      ///
[113]55      /// The \c ItemIntMap must be initialized in such a way, that it
56      /// assigns \c PRE_HEAP (<tt>-1</tt>) to every item.
[100]57      enum State {
58        IN_HEAP = 0,
59        PRE_HEAP = -1,
60        POST_HEAP = -2
61      };
62     
63      /// \brief The constructor.
64      ///
65      /// The constructor.
[113]66      /// \param map A map that assigns \c int values to keys of type
67      /// \c Item. It is used internally by the heap implementations to
68      /// handle the cross references. The assigned value must be
69      /// \c PRE_HEAP (<tt>-1</tt>) for every item.
70      explicit Heap(ItemIntMap &map) {}
[100]71
72      /// \brief The number of items stored in the heap.
73      ///
74      /// Returns the number of items stored in the heap.
75      int size() const { return 0; }
76
[113]77      /// \brief Checks if the heap is empty.
[100]78      ///
[113]79      /// Returns \c true if the heap is empty.
[100]80      bool empty() const { return false; }
81
[113]82      /// \brief Makes the heap empty.
[100]83      ///
[113]84      /// Makes the heap empty.
[100]85      void clear();
86
[113]87      /// \brief Inserts an item into the heap with the given priority.
[100]88      ///   
[113]89      /// Inserts the given item into the heap with the given priority.
[100]90      /// \param i The item to insert.
91      /// \param p The priority of the item.
92      void push(const Item &i, const Prio &p) {}
93
[113]94      /// \brief Returns the item having minimum priority.
[100]95      ///
[113]96      /// Returns the item having minimum priority.
97      /// \pre The heap must be non-empty.
[100]98      Item top() const {}
99
[113]100      /// \brief The minimum priority.
[100]101      ///
[113]102      /// Returns the minimum priority.
103      /// \pre The heap must be non-empty.
[100]104      Prio prio() const {}
105
[113]106      /// \brief Removes the item having minimum priority.
[100]107      ///
[113]108      /// Removes the item having minimum priority.
109      /// \pre The heap must be non-empty.
[100]110      void pop() {}
111
[113]112      /// \brief Removes an item from the heap.
[100]113      ///
[113]114      /// Removes the given item from the heap if it is already stored.
115      /// \param i The item to delete.
[100]116      void erase(const Item &i) {}
117
[113]118      /// \brief The priority of an item.
[100]119      ///
[113]120      /// Returns the priority of the given item. 
[100]121      /// \pre \c i must be in the heap.
122      /// \param i The item.
123      Prio operator[](const Item &i) const {}
124
[113]125      /// \brief Sets the priority of an item or inserts it, if it is
126      /// not stored in the heap.
[100]127      ///
[113]128      /// This method sets the priority of the given item if it is
129      /// already stored in the heap.
130      /// Otherwise it inserts the given item with the given priority.
131      ///
132      /// It may throw an \ref UnderflowPriorityException.
[100]133      /// \param i The item.
134      /// \param p The priority.
135      void set(const Item &i, const Prio &p) {}
136     
[113]137      /// \brief Decreases the priority of an item to the given value.
[100]138      ///
[113]139      /// Decreases the priority of an item to the given value.
[100]140      /// \pre \c i must be stored in the heap with priority at least \c p.
141      /// \param i The item.
142      /// \param p The priority.
143      void decrease(const Item &i, const Prio &p) {}
144
[113]145      /// \brief Increases the priority of an item to the given value.
[100]146      ///
[113]147      /// Increases the priority of an item to the given value.
148      /// \pre \c i must be stored in the heap with priority at most \c p.
[100]149      /// \param i The item.
150      /// \param p The priority.
151      void increase(const Item &i, const Prio &p) {}
152
[113]153      /// \brief Returns if an item is in, has already been in, or has
[100]154      /// never been in the heap.
155      ///
[113]156      /// This method returns \c PRE_HEAP if the given item has never
157      /// been in the heap, \c IN_HEAP if it is in the heap at the moment,
158      /// and \c POST_HEAP otherwise.
159      /// In the latter case it is possible that the item will get back
160      /// to the heap again.
[100]161      /// \param i The item.
162      State state(const Item &i) const {}
163
[113]164      /// \brief Sets the state of an item in the heap.
[100]165      ///
[113]166      /// Sets the state of the given item in the heap. It can be used
167      /// to manually clear the heap when it is important to achive the
[100]168      /// better time complexity.
169      /// \param i The item.
[113]170      /// \param st The state. It should not be \c IN_HEAP.
[100]171      void state(const Item& i, State st) {}
172
173
174      template <typename _Heap>
175      struct Constraints {
176      public:
177        void constraints() {
[113]178          typedef typename _Heap::Item OwnItem;
179          typedef typename _Heap::Prio OwnPrio;
180          typedef typename _Heap::State OwnState;
181
[100]182          Item item;
183          Prio prio;
[113]184          State state;
[100]185          item=Item();
186          prio=Prio();
187          ignore_unused_variable_warning(item);
188          ignore_unused_variable_warning(prio);
[113]189          ignore_unused_variable_warning(state);
[100]190
[113]191          OwnItem own_item;
192          OwnPrio own_prio;
193          OwnState own_state;
194          own_item=Item();
195          own_prio=Prio();
196          ignore_unused_variable_warning(own_item);
197          ignore_unused_variable_warning(own_prio);
198          ignore_unused_variable_warning(own_state);
[100]199
[113]200          _Heap heap1(map);
201          _Heap heap2 = heap1;
[100]202          ignore_unused_variable_warning(heap1);
[113]203          ignore_unused_variable_warning(heap2);
204         
205          int s = heap.size();
206          bool e = heap.empty();
[100]207
208          prio = heap.prio();
209          item = heap.top();
[113]210          prio = heap[item];
211          own_prio = heap.prio();
212          own_item = heap.top();
213          own_prio = heap[own_item];
[100]214
[113]215          heap.push(item, prio);
216          heap.push(own_item, own_prio);
[100]217          heap.pop();
218
219          heap.set(item, prio);
220          heap.decrease(item, prio);
221          heap.increase(item, prio);
[113]222          heap.set(own_item, own_prio);
223          heap.decrease(own_item, own_prio);
224          heap.increase(own_item, own_prio);
[100]225
226          heap.erase(item);
[113]227          heap.erase(own_item);
228          heap.clear();
[100]229
230          state = heap.state(item);
[113]231          heap.state(item, state);
232          state = heap.state(own_item);
233          heap.state(own_item, own_state);
[100]234
235          state = _Heap::PRE_HEAP;
236          state = _Heap::IN_HEAP;
237          state = _Heap::POST_HEAP;
[113]238          own_state = _Heap::PRE_HEAP;
239          own_state = _Heap::IN_HEAP;
240          own_state = _Heap::POST_HEAP;
241        }
[100]242
243        _Heap& heap;
244        ItemIntMap& map;
245      };
246    };
247
248    /// @}
249  } // namespace lemon
250}
251#endif // LEMON_CONCEPT_PATH_H
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