COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/concept/heap.h @ 1993:2115143eceea

Last change on this file since 1993:2115143eceea was 1993:2115143eceea, checked in by Balazs Dezso, 14 years ago

utility, invalid and traits moved to bits

File size: 6.4 KB
Line 
1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2006
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 concept {
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 Item, typename Prio, typename ItemIntMap>
40    class Heap {
41    public:
42 
43
44      /// \brief Type to represent the items states.
45      ///
46      /// Each Item element have a state associated to it. It may be "in heap",
47      /// "pre heap" or "post heap". The later two are indifferent from the
48      /// heap's point of view, but may be useful to the user.
49      ///
50      /// The ItemIntMap _should_ be initialized in such way, that it maps
51      /// PRE_HEAP (-1) to any element to be put in the heap...
52      enum state_enum {
53        IN_HEAP = 0,
54        PRE_HEAP = -1,
55        POST_HEAP = -2
56      };
57     
58      /// \brief The constructor.
59      ///
60      /// The constructor.
61      /// \param _iim should be given to the constructor, since it is used
62      /// internally to handle the cross references. The value of the map
63      /// should be PRE_HEAP (-1) for each element.
64      explicit Heap(ItemIntMap &_iim) {}
65
66      /// \brief The number of items stored in the heap.
67      ///
68      /// Returns the number of items stored in the heap.
69      int size() const { return 0; }
70
71      /// \brief Checks if the heap stores no items.
72      ///
73      /// Returns \c true if and only if the heap stores no items.
74      bool empty() const { return false; }
75
76      /// \brief Makes empty this heap.
77      ///
78      /// Makes this heap empty.
79      void clear();
80
81      /// \brief Insert an item into the heap with the given heap.
82      ///   
83      /// Adds \c i to the heap with priority \c p.
84      /// \param i The item to insert.
85      /// \param p The priority of the item.
86      void push(const Item &i, const Prio &p) {}
87
88      /// \brief Returns the item with minimum priority.
89      ///
90      /// This method returns the item with minimum priority. 
91      /// \pre The heap must be nonempty. 
92      Item top() const {}
93
94      /// \brief Returns the minimum priority.
95      ///
96      /// It returns the minimum priority.
97      /// \pre The heap must be nonempty.
98      Prio prio() const {}
99
100      /// \brief Deletes the item with minimum priority.
101      ///
102      /// This method deletes the item with minimum priority.
103      /// \pre The heap must be non-empty. 
104      void pop() {}
105
106      /// \brief Deletes \c i from the heap.
107      ///
108      /// This method deletes item \c i from the heap, if \c i was
109      /// already stored in the heap.
110      /// \param i The item to erase.
111      void erase(const Item &i) {}
112
113      /// \brief Returns the priority of \c i.
114      ///
115      /// This function returns the priority of item \c i. 
116      /// \pre \c i must be in the heap.
117      /// \param i The item.
118      Prio operator[](const Item &i) const {}
119
120      /// \brief \c i gets to the heap with priority \c p independently
121      /// if \c i was already there.
122      ///
123      /// This method calls \ref push(\c i, \c p) if \c i is not stored
124      /// in the heap and sets the priority of \c i to \c p otherwise.
125      /// It may throw an \e UnderFlowPriorityException.
126      /// \param i The item.
127      /// \param p The priority.
128      void set(const Item &i, const Prio &p) {}
129     
130      /// \brief Decreases the priority of \c i to \c p.
131      ///
132      /// This method decreases the priority of item \c i to \c p.
133      /// \pre \c i must be stored in the heap with priority at least \c p.
134      /// \param i The item.
135      /// \param p The priority.
136      void decrease(const Item &i, const Prio &p) {}
137
138      /// \brief Increases the priority of \c i to \c p.
139      ///
140      /// This method sets the priority of item \c i to \c p.
141      /// \pre \c i must be stored in the heap with priority at most \c
142      /// p relative to \c Compare.
143      /// \param i The item.
144      /// \param p The priority.
145      void increase(const Item &i, const Prio &p) {}
146
147      /// \brief Returns if \c item is in, has already been in, or has
148      /// never been in the heap.
149      ///
150      /// This method returns PRE_HEAP if \c item has never been in the
151      /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
152      /// otherwise. In the latter case it is possible that \c item will
153      /// get back to the heap again.
154      /// \param i The item.
155      state_enum state(const Item &i) const {}
156
157      /// \brief Sets the state of the \c item in the heap.
158      ///
159      /// Sets the state of the \c item in the heap. It can be used to
160      /// manually clear the heap when it is important to achive the
161      /// better time complexity.
162      /// \param i The item.
163      /// \param st The state. It should not be \c IN_HEAP.
164      void state(const Item& i, state_enum st) {}
165
166
167      template <typename _Heap>
168      struct Constraints {
169      public:
170   
171        void constraints() {
172          Item item;
173          Prio prio;
174
175          item=Item();
176          prio=Prio();
177
178          ignore_unused_variable_warning(item);
179          ignore_unused_variable_warning(prio);
180
181          typedef typename _Heap::state_enum state_enum;
182          state_enum state;
183
184          ignore_unused_variable_warning(state);
185     
186          _Heap heap1 = _Heap(map);
187
188          ignore_unused_variable_warning(heap1);
189     
190          heap.push(item, prio);
191
192          prio = heap.prio();
193          item = heap.top();
194
195          heap.pop();
196
197          heap.set(item, prio);
198          heap.decrease(item, prio);
199          heap.increase(item, prio);
200          prio = heap[item];
201
202          heap.erase(item);
203
204          state = heap.state(item);
205
206          state = _Heap::PRE_HEAP;
207          state = _Heap::IN_HEAP;
208          state = _Heap::POST_HEAP;
209
210          heap.clear();
211        }
212   
213        _Heap& heap;
214        ItemIntMap& map;
215
216        Constraints() : heap(0), map(0) {}
217      };
218    };
219
220    /// @}
221  } // namespace lemon
222}
223#endif // LEMON_CONCEPT_PATH_H
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