1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/lemon/concepts/heap.h Thu Feb 07 21:37:07 2008 +0000
1.3 @@ -0,0 +1,226 @@
1.4 +/* -*- C++ -*-
1.5 + *
1.6 + * This file is a part of LEMON, a generic C++ optimization library
1.7 + *
1.8 + * Copyright (C) 2003-2008
1.9 + * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
1.10 + * (Egervary Research Group on Combinatorial Optimization, EGRES).
1.11 + *
1.12 + * Permission to use, modify and distribute this software is granted
1.13 + * provided that this copyright notice appears in all copies. For
1.14 + * precise terms see the accompanying LICENSE file.
1.15 + *
1.16 + * This software is provided "AS IS" with no warranty of any kind,
1.17 + * express or implied, and with no claim as to its suitability for any
1.18 + * purpose.
1.19 + *
1.20 + */
1.21 +
1.22 +///\ingroup concept
1.23 +///\file
1.24 +///\brief Classes for representing heaps.
1.25 +///
1.26 +
1.27 +#ifndef LEMON_CONCEPT_HEAP_H
1.28 +#define LEMON_CONCEPT_HEAP_H
1.29 +
1.30 +#include <lemon/bits/invalid.h>
1.31 +
1.32 +namespace lemon {
1.33 + namespace concepts {
1.34 + /// \addtogroup concept
1.35 + /// @{
1.36 +
1.37 +
1.38 + /// \brief A concept structure describes the main interface of heaps.
1.39 + ///
1.40 + /// A concept structure describes the main interface of heaps.
1.41 + ///
1.42 + template <typename Prio, typename ItemIntMap>
1.43 + class Heap {
1.44 + public:
1.45 +
1.46 + ///\brief Type of the items stored in the heap.
1.47 + typedef typename ItemIntMap::Key Item;
1.48 +
1.49 +
1.50 + /// \brief Type to represent the items states.
1.51 + ///
1.52 + /// Each Item element have a state associated to it. It may be "in heap",
1.53 + /// "pre heap" or "post heap". The later two are indifferent from the
1.54 + /// heap's point of view, but may be useful to the user.
1.55 + ///
1.56 + /// The ItemIntMap _should_ be initialized in such way, that it maps
1.57 + /// PRE_HEAP (-1) to any element to be put in the heap...
1.58 + enum State {
1.59 + IN_HEAP = 0,
1.60 + PRE_HEAP = -1,
1.61 + POST_HEAP = -2
1.62 + };
1.63 +
1.64 + /// \brief The constructor.
1.65 + ///
1.66 + /// The constructor.
1.67 + /// \param _iim should be given to the constructor, since it is used
1.68 + /// internally to handle the cross references. The value of the map
1.69 + /// should be PRE_HEAP (-1) for each element.
1.70 + explicit Heap(ItemIntMap &_iim) {}
1.71 +
1.72 + /// \brief The number of items stored in the heap.
1.73 + ///
1.74 + /// Returns the number of items stored in the heap.
1.75 + int size() const { return 0; }
1.76 +
1.77 + /// \brief Checks if the heap stores no items.
1.78 + ///
1.79 + /// Returns \c true if and only if the heap stores no items.
1.80 + bool empty() const { return false; }
1.81 +
1.82 + /// \brief Makes empty this heap.
1.83 + ///
1.84 + /// Makes this heap empty.
1.85 + void clear();
1.86 +
1.87 + /// \brief Insert an item into the heap with the given heap.
1.88 + ///
1.89 + /// Adds \c i to the heap with priority \c p.
1.90 + /// \param i The item to insert.
1.91 + /// \param p The priority of the item.
1.92 + void push(const Item &i, const Prio &p) {}
1.93 +
1.94 + /// \brief Returns the item with minimum priority.
1.95 + ///
1.96 + /// This method returns the item with minimum priority.
1.97 + /// \pre The heap must be nonempty.
1.98 + Item top() const {}
1.99 +
1.100 + /// \brief Returns the minimum priority.
1.101 + ///
1.102 + /// It returns the minimum priority.
1.103 + /// \pre The heap must be nonempty.
1.104 + Prio prio() const {}
1.105 +
1.106 + /// \brief Deletes the item with minimum priority.
1.107 + ///
1.108 + /// This method deletes the item with minimum priority.
1.109 + /// \pre The heap must be non-empty.
1.110 + void pop() {}
1.111 +
1.112 + /// \brief Deletes \c i from the heap.
1.113 + ///
1.114 + /// This method deletes item \c i from the heap, if \c i was
1.115 + /// already stored in the heap.
1.116 + /// \param i The item to erase.
1.117 + void erase(const Item &i) {}
1.118 +
1.119 + /// \brief Returns the priority of \c i.
1.120 + ///
1.121 + /// This function returns the priority of item \c i.
1.122 + /// \pre \c i must be in the heap.
1.123 + /// \param i The item.
1.124 + Prio operator[](const Item &i) const {}
1.125 +
1.126 + /// \brief \c i gets to the heap with priority \c p independently
1.127 + /// if \c i was already there.
1.128 + ///
1.129 + /// This method calls \ref push(\c i, \c p) if \c i is not stored
1.130 + /// in the heap and sets the priority of \c i to \c p otherwise.
1.131 + /// It may throw an \e UnderFlowPriorityException.
1.132 + /// \param i The item.
1.133 + /// \param p The priority.
1.134 + void set(const Item &i, const Prio &p) {}
1.135 +
1.136 + /// \brief Decreases the priority of \c i to \c p.
1.137 + ///
1.138 + /// This method decreases the priority of item \c i to \c p.
1.139 + /// \pre \c i must be stored in the heap with priority at least \c p.
1.140 + /// \param i The item.
1.141 + /// \param p The priority.
1.142 + void decrease(const Item &i, const Prio &p) {}
1.143 +
1.144 + /// \brief Increases the priority of \c i to \c p.
1.145 + ///
1.146 + /// This method sets the priority of item \c i to \c p.
1.147 + /// \pre \c i must be stored in the heap with priority at most \c
1.148 + /// p relative to \c Compare.
1.149 + /// \param i The item.
1.150 + /// \param p The priority.
1.151 + void increase(const Item &i, const Prio &p) {}
1.152 +
1.153 + /// \brief Returns if \c item is in, has already been in, or has
1.154 + /// never been in the heap.
1.155 + ///
1.156 + /// This method returns PRE_HEAP if \c item has never been in the
1.157 + /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
1.158 + /// otherwise. In the latter case it is possible that \c item will
1.159 + /// get back to the heap again.
1.160 + /// \param i The item.
1.161 + State state(const Item &i) const {}
1.162 +
1.163 + /// \brief Sets the state of the \c item in the heap.
1.164 + ///
1.165 + /// Sets the state of the \c item in the heap. It can be used to
1.166 + /// manually clear the heap when it is important to achive the
1.167 + /// better time complexity.
1.168 + /// \param i The item.
1.169 + /// \param st The state. It should not be \c IN_HEAP.
1.170 + void state(const Item& i, State st) {}
1.171 +
1.172 +
1.173 + template <typename _Heap>
1.174 + struct Constraints {
1.175 + public:
1.176 +
1.177 + void constraints() {
1.178 + Item item;
1.179 + Prio prio;
1.180 +
1.181 + item=Item();
1.182 + prio=Prio();
1.183 +
1.184 + ignore_unused_variable_warning(item);
1.185 + ignore_unused_variable_warning(prio);
1.186 +
1.187 + typedef typename _Heap::State State;
1.188 + State state;
1.189 +
1.190 + ignore_unused_variable_warning(state);
1.191 +
1.192 + _Heap heap1 = _Heap(map);
1.193 +
1.194 + ignore_unused_variable_warning(heap1);
1.195 +
1.196 + heap.push(item, prio);
1.197 +
1.198 + prio = heap.prio();
1.199 + item = heap.top();
1.200 +
1.201 + heap.pop();
1.202 +
1.203 + heap.set(item, prio);
1.204 + heap.decrease(item, prio);
1.205 + heap.increase(item, prio);
1.206 + prio = heap[item];
1.207 +
1.208 + heap.erase(item);
1.209 +
1.210 + state = heap.state(item);
1.211 +
1.212 + state = _Heap::PRE_HEAP;
1.213 + state = _Heap::IN_HEAP;
1.214 + state = _Heap::POST_HEAP;
1.215 +
1.216 + heap.clear();
1.217 + }
1.218 +
1.219 + _Heap& heap;
1.220 + ItemIntMap& map;
1.221 +
1.222 + Constraints() : heap(0), map(0) {}
1.223 + };
1.224 + };
1.225 +
1.226 + /// @}
1.227 + } // namespace lemon
1.228 +}
1.229 +#endif // LEMON_CONCEPT_PATH_H