COIN-OR::LEMON - Graph Library

source: lemon/lemon/concepts/heap.h @ 290:f6899946c1ac

Last change on this file since 290:f6899946c1ac was 290:f6899946c1ac, checked in by Balazs Dezso <deba@…>, 11 years ago

Simplifying exceptions

  • Using asserts instead of exceptions for unitialized parameters
  • Only the IO exceptions are used in the lemon
  • DataFormatError? is renamed to FormatError?
  • The IoError? is used for file access errors
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) 2003-2008
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
21///\brief The concept of heaps.
22
23#ifndef LEMON_CONCEPT_HEAP_H
24#define LEMON_CONCEPT_HEAP_H
25
26#include <lemon/core.h>
27
28namespace lemon {
29
30  namespace concepts {
31
32    /// \addtogroup concept
33    /// @{
34
35    /// \brief The heap concept.
36    ///
37    /// Concept class describing the main interface of heaps.
38    template <typename Priority, typename ItemIntMap>
39    class Heap {
40    public:
41
42      /// Type of the items stored in the heap.
43      typedef typename ItemIntMap::Key Item;
44
45      /// Type of the priorities.
46      typedef Priority Prio;
47
48      /// \brief Type to represent the states of the items.
49      ///
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.
54      ///
55      /// The \c ItemIntMap must be initialized in such a way, that it
56      /// assigns \c PRE_HEAP (<tt>-1</tt>) to every item.
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.
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) {}
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
77      /// \brief Checks if the heap is empty.
78      ///
79      /// Returns \c true if the heap is empty.
80      bool empty() const { return false; }
81
82      /// \brief Makes the heap empty.
83      ///
84      /// Makes the heap empty.
85      void clear();
86
87      /// \brief Inserts an item into the heap with the given priority.
88      ///
89      /// Inserts the given item into the heap with the given priority.
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
94      /// \brief Returns the item having minimum priority.
95      ///
96      /// Returns the item having minimum priority.
97      /// \pre The heap must be non-empty.
98      Item top() const {}
99
100      /// \brief The minimum priority.
101      ///
102      /// Returns the minimum priority.
103      /// \pre The heap must be non-empty.
104      Prio prio() const {}
105
106      /// \brief Removes the item having minimum priority.
107      ///
108      /// Removes the item having minimum priority.
109      /// \pre The heap must be non-empty.
110      void pop() {}
111
112      /// \brief Removes an item from the heap.
113      ///
114      /// Removes the given item from the heap if it is already stored.
115      /// \param i The item to delete.
116      void erase(const Item &i) {}
117
118      /// \brief The priority of an item.
119      ///
120      /// Returns the priority of the given item.
121      /// \pre \c i must be in the heap.
122      /// \param i The item.
123      Prio operator[](const Item &i) const {}
124
125      /// \brief Sets the priority of an item or inserts it, if it is
126      /// not stored in the heap.
127      ///
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      /// \param i The item.
133      /// \param p The priority.
134      void set(const Item &i, const Prio &p) {}
135
136      /// \brief Decreases the priority of an item to the given value.
137      ///
138      /// Decreases the priority of an item to the given value.
139      /// \pre \c i must be stored in the heap with priority at least \c p.
140      /// \param i The item.
141      /// \param p The priority.
142      void decrease(const Item &i, const Prio &p) {}
143
144      /// \brief Increases the priority of an item to the given value.
145      ///
146      /// Increases the priority of an item to the given value.
147      /// \pre \c i must be stored in the heap with priority at most \c p.
148      /// \param i The item.
149      /// \param p The priority.
150      void increase(const Item &i, const Prio &p) {}
151
152      /// \brief Returns if an item is in, has already been in, or has
153      /// never been in the heap.
154      ///
155      /// This method returns \c PRE_HEAP if the given item has never
156      /// been in the heap, \c IN_HEAP if it is in the heap at the moment,
157      /// and \c POST_HEAP otherwise.
158      /// In the latter case it is possible that the item will get back
159      /// to the heap again.
160      /// \param i The item.
161      State state(const Item &i) const {}
162
163      /// \brief Sets the state of an item in the heap.
164      ///
165      /// Sets the state of the given item in the heap. It can be used
166      /// to manually clear the heap when it is important to achive the
167      /// better time complexity.
168      /// \param i The item.
169      /// \param st The state. It should not be \c IN_HEAP.
170      void state(const Item& i, State st) {}
171
172
173      template <typename _Heap>
174      struct Constraints {
175      public:
176        void constraints() {
177          typedef typename _Heap::Item OwnItem;
178          typedef typename _Heap::Prio OwnPrio;
179          typedef typename _Heap::State OwnState;
180
181          Item item;
182          Prio prio;
183          item=Item();
184          prio=Prio();
185          ignore_unused_variable_warning(item);
186          ignore_unused_variable_warning(prio);
187
188          OwnItem own_item;
189          OwnPrio own_prio;
190          OwnState own_state;
191          own_item=Item();
192          own_prio=Prio();
193          ignore_unused_variable_warning(own_item);
194          ignore_unused_variable_warning(own_prio);
195          ignore_unused_variable_warning(own_state);
196
197          _Heap heap1(map);
198          _Heap heap2 = heap1;
199          ignore_unused_variable_warning(heap1);
200          ignore_unused_variable_warning(heap2);
201
202          int s = heap.size();
203          ignore_unused_variable_warning(s);
204          bool e = heap.empty();
205          ignore_unused_variable_warning(e);
206
207          prio = heap.prio();
208          item = heap.top();
209          prio = heap[item];
210          own_prio = heap.prio();
211          own_item = heap.top();
212          own_prio = heap[own_item];
213
214          heap.push(item, prio);
215          heap.push(own_item, own_prio);
216          heap.pop();
217
218          heap.set(item, prio);
219          heap.decrease(item, prio);
220          heap.increase(item, prio);
221          heap.set(own_item, own_prio);
222          heap.decrease(own_item, own_prio);
223          heap.increase(own_item, own_prio);
224
225          heap.erase(item);
226          heap.erase(own_item);
227          heap.clear();
228
229          own_state = heap.state(own_item);
230          heap.state(own_item, own_state);
231
232          own_state = _Heap::PRE_HEAP;
233          own_state = _Heap::IN_HEAP;
234          own_state = _Heap::POST_HEAP;
235        }
236
237        _Heap& heap;
238        ItemIntMap& map;
239      };
240    };
241
242    /// @}
243  } // namespace lemon
244}
245#endif // LEMON_CONCEPT_PATH_H
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