COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/concepts/heap.h @ 2547:f393a8162688

Last change on this file since 2547:f393a8162688 was 2547:f393a8162688, checked in by Balazs Dezso, 12 years ago

Renaming state_enum to State
Removing "Type" suffix from typedefs
Moving implementation into the class definition

File size: 6.5 KB
Line 
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
29namespace 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 {
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 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 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 State;
185          State 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
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