COIN-OR::LEMON - Graph Library

source: lemon/lemon/concepts/heap.h @ 576:f5bc148f7e1f

Last change on this file since 576:f5bc148f7e1f was 576:f5bc148f7e1f, checked in by Balazs Dezso <deba@…>, 10 years ago

Fix the naming convention of guards and remove one unnecessary include

File size: 7.5 KB
Line 
1/* -*- mode: C++; indent-tabs-mode: nil; -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library.
4 *
5 * Copyright (C) 2003-2009
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 The concept of heaps.
22
23#ifndef LEMON_CONCEPTS_HEAP_H
24#define LEMON_CONCEPTS_HEAP_H
25
26#include <lemon/core.h>
27#include <lemon/concept_check.h>
28
29namespace lemon {
30
31  namespace concepts {
32
33    /// \addtogroup concept
34    /// @{
35
36    /// \brief The heap concept.
37    ///
38    /// Concept class describing the main interface of heaps.
39    template <typename Priority, typename ItemIntMap>
40    class Heap {
41    public:
42
43      /// Type of the items stored in the heap.
44      typedef typename ItemIntMap::Key Item;
45
46      /// Type of the priorities.
47      typedef Priority Prio;
48
49      /// \brief Type to represent the states of the items.
50      ///
51      /// Each item has a state associated to it. It can be "in heap",
52      /// "pre heap" or "post heap". The later two are indifferent
53      /// from the point of view of the heap, but may be useful for
54      /// the user.
55      ///
56      /// The \c ItemIntMap must be initialized in such a way, that it
57      /// assigns \c PRE_HEAP (<tt>-1</tt>) to every item.
58      enum State {
59        IN_HEAP = 0,
60        PRE_HEAP = -1,
61        POST_HEAP = -2
62      };
63
64      /// \brief The constructor.
65      ///
66      /// The constructor.
67      /// \param map A map that assigns \c int values to keys of type
68      /// \c Item. It is used internally by the heap implementations to
69      /// handle the cross references. The assigned value must be
70      /// \c PRE_HEAP (<tt>-1</tt>) for every item.
71      explicit Heap(ItemIntMap &map) {}
72
73      /// \brief The number of items stored in the heap.
74      ///
75      /// Returns the number of items stored in the heap.
76      int size() const { return 0; }
77
78      /// \brief Checks if the heap is empty.
79      ///
80      /// Returns \c true if the heap is empty.
81      bool empty() const { return false; }
82
83      /// \brief Makes the heap empty.
84      ///
85      /// Makes the heap empty.
86      void clear();
87
88      /// \brief Inserts an item into the heap with the given priority.
89      ///
90      /// Inserts the given item into the heap with the given priority.
91      /// \param i The item to insert.
92      /// \param p The priority of the item.
93      void push(const Item &i, const Prio &p) {}
94
95      /// \brief Returns the item having minimum priority.
96      ///
97      /// Returns the item having minimum priority.
98      /// \pre The heap must be non-empty.
99      Item top() const {}
100
101      /// \brief The minimum priority.
102      ///
103      /// Returns the minimum priority.
104      /// \pre The heap must be non-empty.
105      Prio prio() const {}
106
107      /// \brief Removes the item having minimum priority.
108      ///
109      /// Removes the item having minimum priority.
110      /// \pre The heap must be non-empty.
111      void pop() {}
112
113      /// \brief Removes an item from the heap.
114      ///
115      /// Removes the given item from the heap if it is already stored.
116      /// \param i The item to delete.
117      void erase(const Item &i) {}
118
119      /// \brief The priority of an item.
120      ///
121      /// Returns the priority of the given item.
122      /// \pre \c i must be in the heap.
123      /// \param i The item.
124      Prio operator[](const Item &i) const {}
125
126      /// \brief Sets the priority of an item or inserts it, if it is
127      /// not stored in the heap.
128      ///
129      /// This method sets the priority of the given item if it is
130      /// already stored in the heap.
131      /// Otherwise it inserts the given item with the given priority.
132      ///
133      /// \param i The item.
134      /// \param p The priority.
135      void set(const Item &i, const Prio &p) {}
136
137      /// \brief Decreases the priority of an item to the given value.
138      ///
139      /// Decreases the priority of an item to the given value.
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
145      /// \brief Increases the priority of an item to the given value.
146      ///
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.
149      /// \param i The item.
150      /// \param p The priority.
151      void increase(const Item &i, const Prio &p) {}
152
153      /// \brief Returns if an item is in, has already been in, or has
154      /// never been in the heap.
155      ///
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.
161      /// \param i The item.
162      State state(const Item &i) const {}
163
164      /// \brief Sets the state of an item in the heap.
165      ///
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
168      /// better time complexity.
169      /// \param i The item.
170      /// \param st The state. It should not be \c IN_HEAP.
171      void state(const Item& i, State st) {}
172
173
174      template <typename _Heap>
175      struct Constraints {
176      public:
177        void constraints() {
178          typedef typename _Heap::Item OwnItem;
179          typedef typename _Heap::Prio OwnPrio;
180          typedef typename _Heap::State OwnState;
181
182          Item item;
183          Prio prio;
184          item=Item();
185          prio=Prio();
186          ignore_unused_variable_warning(item);
187          ignore_unused_variable_warning(prio);
188
189          OwnItem own_item;
190          OwnPrio own_prio;
191          OwnState own_state;
192          own_item=Item();
193          own_prio=Prio();
194          ignore_unused_variable_warning(own_item);
195          ignore_unused_variable_warning(own_prio);
196          ignore_unused_variable_warning(own_state);
197
198          _Heap heap1(map);
199          _Heap heap2 = heap1;
200          ignore_unused_variable_warning(heap1);
201          ignore_unused_variable_warning(heap2);
202
203          int s = heap.size();
204          ignore_unused_variable_warning(s);
205          bool e = heap.empty();
206          ignore_unused_variable_warning(e);
207
208          prio = heap.prio();
209          item = heap.top();
210          prio = heap[item];
211          own_prio = heap.prio();
212          own_item = heap.top();
213          own_prio = heap[own_item];
214
215          heap.push(item, prio);
216          heap.push(own_item, own_prio);
217          heap.pop();
218
219          heap.set(item, prio);
220          heap.decrease(item, prio);
221          heap.increase(item, prio);
222          heap.set(own_item, own_prio);
223          heap.decrease(own_item, own_prio);
224          heap.increase(own_item, own_prio);
225
226          heap.erase(item);
227          heap.erase(own_item);
228          heap.clear();
229
230          own_state = heap.state(own_item);
231          heap.state(own_item, own_state);
232
233          own_state = _Heap::PRE_HEAP;
234          own_state = _Heap::IN_HEAP;
235          own_state = _Heap::POST_HEAP;
236        }
237
238        _Heap& heap;
239        ItemIntMap& map;
240      };
241    };
242
243    /// @}
244  } // namespace lemon
245}
246#endif
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