COIN-OR::LEMON - Graph Library

source: lemon/lemon/concepts/heap.h @ 606:c5fd2d996909

Last change on this file since 606:c5fd2d996909 was 606:c5fd2d996909, checked in by Peter Kovacs <kpeter@…>, 11 years ago

Various doc improvements (#248)

  • Rename all the ugly template parameters (too long and/or starting with an underscore).
  • Rename function parameters starting with an underscore.
  • Extend the doc for many classes.
  • Use LaTeX-style O(...) expressions only for the complicated ones.
  • A lot of small unification changes.
  • Small fixes.
  • Some other improvements.
File size: 8.4 KB
RevLine 
[209]1/* -*- mode: C++; indent-tabs-mode: nil; -*-
[100]2 *
[209]3 * This file is a part of LEMON, a generic C++ optimization library.
[100]4 *
[463]5 * Copyright (C) 2003-2009
[100]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
[576]23#ifndef LEMON_CONCEPTS_HEAP_H
24#define LEMON_CONCEPTS_HEAP_H
[100]25
[220]26#include <lemon/core.h>
[566]27#include <lemon/concept_check.h>
[100]28
29namespace lemon {
[113]30
[100]31  namespace concepts {
[113]32
[100]33    /// \addtogroup concept
34    /// @{
35
[113]36    /// \brief The heap concept.
[100]37    ///
[606]38    /// Concept class describing the main interface of heaps. A \e heap
39    /// is a data structure for storing items with specified values called
40    /// \e priorities in such a way that finding the item with minimum
41    /// priority is efficient. In a heap one can change the priority of an
42    /// item, add or erase an item, etc.
43    ///
44    /// \tparam PR Type of the priority of the items.
45    /// \tparam IM A read and writable item map with int values, used
46    /// internally to handle the cross references.
47    /// \tparam Comp A functor class for the ordering of the priorities.
48    /// The default is \c std::less<PR>.
49#ifdef DOXYGEN
50    template <typename PR, typename IM, typename Comp = std::less<PR> >
51#else
52    template <typename PR, typename IM>
53#endif
[100]54    class Heap {
55    public:
56
[606]57      /// Type of the item-int map.
58      typedef IM ItemIntMap;
59      /// Type of the priorities.
60      typedef PR Prio;
[113]61      /// Type of the items stored in the heap.
62      typedef typename ItemIntMap::Key Item;
[100]63
[113]64      /// \brief Type to represent the states of the items.
[100]65      ///
[113]66      /// Each item has a state associated to it. It can be "in heap",
67      /// "pre heap" or "post heap". The later two are indifferent
68      /// from the point of view of the heap, but may be useful for
69      /// the user.
[100]70      ///
[606]71      /// The item-int map must be initialized in such way that it assigns
72      /// \c PRE_HEAP (<tt>-1</tt>) to any element to be put in the heap.
[100]73      enum State {
[606]74        IN_HEAP = 0,    ///< The "in heap" state constant.
75        PRE_HEAP = -1,  ///< The "pre heap" state constant.
76        POST_HEAP = -2  ///< The "post heap" state constant.
[100]77      };
[209]78
[100]79      /// \brief The constructor.
80      ///
81      /// The constructor.
[113]82      /// \param map A map that assigns \c int values to keys of type
83      /// \c Item. It is used internally by the heap implementations to
84      /// handle the cross references. The assigned value must be
85      /// \c PRE_HEAP (<tt>-1</tt>) for every item.
86      explicit Heap(ItemIntMap &map) {}
[100]87
88      /// \brief The number of items stored in the heap.
89      ///
90      /// Returns the number of items stored in the heap.
91      int size() const { return 0; }
92
[113]93      /// \brief Checks if the heap is empty.
[100]94      ///
[113]95      /// Returns \c true if the heap is empty.
[100]96      bool empty() const { return false; }
97
[113]98      /// \brief Makes the heap empty.
[100]99      ///
[113]100      /// Makes the heap empty.
[100]101      void clear();
102
[113]103      /// \brief Inserts an item into the heap with the given priority.
[209]104      ///
105      /// Inserts the given item into the heap with the given priority.
[100]106      /// \param i The item to insert.
107      /// \param p The priority of the item.
108      void push(const Item &i, const Prio &p) {}
109
[113]110      /// \brief Returns the item having minimum priority.
[100]111      ///
[113]112      /// Returns the item having minimum priority.
113      /// \pre The heap must be non-empty.
[100]114      Item top() const {}
115
[113]116      /// \brief The minimum priority.
[100]117      ///
[113]118      /// Returns the minimum priority.
119      /// \pre The heap must be non-empty.
[100]120      Prio prio() const {}
121
[113]122      /// \brief Removes the item having minimum priority.
[100]123      ///
[113]124      /// Removes the item having minimum priority.
125      /// \pre The heap must be non-empty.
[100]126      void pop() {}
127
[113]128      /// \brief Removes an item from the heap.
[100]129      ///
[113]130      /// Removes the given item from the heap if it is already stored.
[209]131      /// \param i The item to delete.
[100]132      void erase(const Item &i) {}
133
[113]134      /// \brief The priority of an item.
[100]135      ///
[209]136      /// Returns the priority of the given item.
[606]137      /// \param i The item.
[100]138      /// \pre \c i must be in the heap.
139      Prio operator[](const Item &i) const {}
140
[113]141      /// \brief Sets the priority of an item or inserts it, if it is
142      /// not stored in the heap.
[100]143      ///
[113]144      /// This method sets the priority of the given item if it is
145      /// already stored in the heap.
146      /// Otherwise it inserts the given item with the given priority.
147      ///
[100]148      /// \param i The item.
149      /// \param p The priority.
150      void set(const Item &i, const Prio &p) {}
[209]151
[113]152      /// \brief Decreases the priority of an item to the given value.
[100]153      ///
[113]154      /// Decreases the priority of an item to the given value.
[100]155      /// \param i The item.
156      /// \param p The priority.
[606]157      /// \pre \c i must be stored in the heap with priority at least \c p.
[100]158      void decrease(const Item &i, const Prio &p) {}
159
[113]160      /// \brief Increases the priority of an item to the given value.
[100]161      ///
[113]162      /// Increases the priority of an item to the given value.
[100]163      /// \param i The item.
164      /// \param p The priority.
[606]165      /// \pre \c i must be stored in the heap with priority at most \c p.
[100]166      void increase(const Item &i, const Prio &p) {}
167
[113]168      /// \brief Returns if an item is in, has already been in, or has
[100]169      /// never been in the heap.
170      ///
[113]171      /// This method returns \c PRE_HEAP if the given item has never
172      /// been in the heap, \c IN_HEAP if it is in the heap at the moment,
173      /// and \c POST_HEAP otherwise.
174      /// In the latter case it is possible that the item will get back
175      /// to the heap again.
[100]176      /// \param i The item.
177      State state(const Item &i) const {}
178
[113]179      /// \brief Sets the state of an item in the heap.
[100]180      ///
[113]181      /// Sets the state of the given item in the heap. It can be used
182      /// to manually clear the heap when it is important to achive the
[100]183      /// better time complexity.
184      /// \param i The item.
[113]185      /// \param st The state. It should not be \c IN_HEAP.
[100]186      void state(const Item& i, State st) {}
187
188
189      template <typename _Heap>
190      struct Constraints {
191      public:
[209]192        void constraints() {
193          typedef typename _Heap::Item OwnItem;
194          typedef typename _Heap::Prio OwnPrio;
195          typedef typename _Heap::State OwnState;
[113]196
[209]197          Item item;
198          Prio prio;
199          item=Item();
200          prio=Prio();
201          ignore_unused_variable_warning(item);
202          ignore_unused_variable_warning(prio);
[100]203
[209]204          OwnItem own_item;
205          OwnPrio own_prio;
206          OwnState own_state;
207          own_item=Item();
208          own_prio=Prio();
209          ignore_unused_variable_warning(own_item);
210          ignore_unused_variable_warning(own_prio);
211          ignore_unused_variable_warning(own_state);
[100]212
[209]213          _Heap heap1(map);
214          _Heap heap2 = heap1;
215          ignore_unused_variable_warning(heap1);
216          ignore_unused_variable_warning(heap2);
[100]217
[209]218          int s = heap.size();
219          ignore_unused_variable_warning(s);
220          bool e = heap.empty();
221          ignore_unused_variable_warning(e);
[100]222
[209]223          prio = heap.prio();
224          item = heap.top();
225          prio = heap[item];
226          own_prio = heap.prio();
227          own_item = heap.top();
228          own_prio = heap[own_item];
[100]229
[209]230          heap.push(item, prio);
231          heap.push(own_item, own_prio);
232          heap.pop();
[100]233
[209]234          heap.set(item, prio);
235          heap.decrease(item, prio);
236          heap.increase(item, prio);
237          heap.set(own_item, own_prio);
238          heap.decrease(own_item, own_prio);
239          heap.increase(own_item, own_prio);
[100]240
[209]241          heap.erase(item);
242          heap.erase(own_item);
243          heap.clear();
[100]244
[209]245          own_state = heap.state(own_item);
246          heap.state(own_item, own_state);
[100]247
[209]248          own_state = _Heap::PRE_HEAP;
249          own_state = _Heap::IN_HEAP;
250          own_state = _Heap::POST_HEAP;
251        }
252
253        _Heap& heap;
254        ItemIntMap& map;
[100]255      };
256    };
257
258    /// @}
259  } // namespace lemon
260}
[576]261#endif
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