1 | /* -*- C++ -*- |
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2 | * lemon/concept/heap.h - Part of LEMON, a generic C++ optimization library |
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3 | * |
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4 | * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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5 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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6 | * |
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7 | * Permission to use, modify and distribute this software is granted |
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8 | * provided that this copyright notice appears in all copies. For |
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9 | * precise terms see the accompanying LICENSE file. |
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10 | * |
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11 | * This software is provided "AS IS" with no warranty of any kind, |
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12 | * express or implied, and with no claim as to its suitability for any |
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13 | * purpose. |
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14 | * |
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15 | */ |
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16 | |
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17 | ///\ingroup concept |
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18 | ///\file |
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19 | ///\brief Classes for representing heaps. |
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20 | /// |
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21 | |
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22 | #ifndef LEMON_CONCEPT_HEAP_H |
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23 | #define LEMON_CONCEPT_HEAP_H |
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24 | |
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25 | #include <lemon/invalid.h> |
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26 | |
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27 | namespace lemon { |
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28 | namespace concept { |
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29 | /// \addtogroup concept |
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30 | /// @{ |
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31 | |
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32 | |
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33 | /// \brief A concept structure describes the main interface of heaps. |
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34 | /// |
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35 | /// A concept structure describes the main interface of heaps. |
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36 | /// |
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37 | template <typename Item, typename Prio, typename ItemIntMap> |
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38 | class Heap { |
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39 | public: |
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40 | |
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41 | |
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42 | /// \brief Type to represent the items states. |
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43 | /// |
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44 | /// Each Item element have a state associated to it. It may be "in heap", |
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45 | /// "pre heap" or "post heap". The later two are indifferent from the |
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46 | /// heap's point of view, but may be useful to the user. |
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47 | /// |
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48 | /// The ItemIntMap _should_ be initialized in such way, that it maps |
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49 | /// PRE_HEAP (-1) to any element to be put in the heap... |
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50 | enum state_enum { |
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51 | IN_HEAP = 0, |
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52 | PRE_HEAP = -1, |
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53 | POST_HEAP = -2 |
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54 | }; |
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55 | |
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56 | /// \brief The constructor. |
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57 | /// |
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58 | /// The constructor. |
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59 | /// \param _iim should be given to the constructor, since it is used |
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60 | /// internally to handle the cross references. The value of the map |
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61 | /// should be PRE_HEAP (-1) for each element. |
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62 | explicit Heap(ItemIntMap &_iim) {} |
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63 | |
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64 | /// The number of items stored in the heap. |
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65 | /// |
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66 | /// \brief Returns the number of items stored in the heap. |
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67 | int size() const { return 0; } |
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68 | /// \brief Checks if the heap stores no items. |
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69 | /// |
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70 | /// Returns \c true if and only if the heap stores no items. |
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71 | bool empty() const { return false; } |
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72 | |
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73 | /// \brief Insert an item into the heap with the given heap. |
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74 | /// |
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75 | /// Adds \c i to the heap with priority \c p. |
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76 | /// \param i The item to insert. |
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77 | /// \param p The priority of the item. |
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78 | void push(const Item &i, const Prio &p) {} |
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79 | |
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80 | /// \brief Returns the item with minimum priority. |
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81 | /// |
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82 | /// This method returns the item with minimum priority. |
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83 | /// \pre The heap must be nonempty. |
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84 | Item top() const {} |
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85 | |
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86 | /// \brief Returns the minimum priority. |
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87 | /// |
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88 | /// It returns the minimum priority. |
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89 | /// \pre The heap must be nonempty. |
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90 | Prio prio() const {} |
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91 | |
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92 | /// \brief Deletes the item with minimum priority. |
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93 | /// |
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94 | /// This method deletes the item with minimum priority. |
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95 | /// \pre The heap must be non-empty. |
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96 | void pop() {} |
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97 | |
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98 | /// \brief Deletes \c i from the heap. |
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99 | /// |
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100 | /// This method deletes item \c i from the heap, if \c i was |
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101 | /// already stored in the heap. |
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102 | /// \param i The item to erase. |
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103 | void erase(const Item &i) {} |
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104 | |
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105 | /// \brief Returns the priority of \c i. |
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106 | /// |
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107 | /// This function returns the priority of item \c i. |
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108 | /// \pre \c i must be in the heap. |
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109 | /// \param i The item. |
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110 | Prio operator[](const Item &i) const {} |
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111 | |
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112 | /// \brief \c i gets to the heap with priority \c p independently |
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113 | /// if \c i was already there. |
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114 | /// |
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115 | /// This method calls \ref push(\c i, \c p) if \c i is not stored |
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116 | /// in the heap and sets the priority of \c i to \c p otherwise. |
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117 | /// It may throw an \e UnderFlowPriorityException. |
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118 | /// \param i The item. |
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119 | /// \param p The priority. |
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120 | void set(const Item &i, const Prio &p) {} |
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121 | |
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122 | /// \brief Decreases the priority of \c i to \c p. |
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123 | /// |
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124 | /// This method decreases the priority of item \c i to \c p. |
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125 | /// \pre \c i must be stored in the heap with priority at least \c p. |
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126 | /// \param i The item. |
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127 | /// \param p The priority. |
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128 | void decrease(const Item &i, const Prio &p) {} |
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129 | |
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130 | /// \brief Increases the priority of \c i to \c p. |
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131 | /// |
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132 | /// This method sets the priority of item \c i to \c p. |
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133 | /// \pre \c i must be stored in the heap with priority at most \c |
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134 | /// p relative to \c Compare. |
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135 | /// \param i The item. |
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136 | /// \param p The priority. |
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137 | void increase(const Item &i, const Prio &p) {} |
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138 | |
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139 | /// \brief Returns if \c item is in, has already been in, or has |
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140 | /// never been in the heap. |
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141 | /// |
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142 | /// This method returns PRE_HEAP if \c item has never been in the |
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143 | /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP |
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144 | /// otherwise. In the latter case it is possible that \c item will |
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145 | /// get back to the heap again. |
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146 | /// \param i The item. |
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147 | state_enum state(const Item &i) const {} |
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148 | |
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149 | |
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150 | template <typename _Heap> |
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151 | struct Constraints { |
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152 | public: |
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153 | |
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154 | void constraints() { |
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155 | Item item; |
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156 | Prio prio; |
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157 | |
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158 | ignore_unused_variable_warning(item); |
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159 | ignore_unused_variable_warning(prio); |
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160 | |
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161 | typedef typename _Heap::state_enum state_enum; |
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162 | state_enum state; |
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163 | |
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164 | ignore_unused_variable_warning(state); |
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165 | |
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166 | _Heap heap1 = _Heap(map); |
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167 | |
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168 | ignore_unused_variable_warning(heap1); |
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169 | |
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170 | heap.push(item, prio); |
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171 | |
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172 | prio = heap.prio(); |
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173 | item = heap.top(); |
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174 | |
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175 | heap.pop(); |
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176 | |
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177 | heap.set(item, prio); |
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178 | heap.decrease(item, prio); |
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179 | heap.increase(item, prio); |
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180 | prio = heap[item]; |
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181 | |
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182 | heap.erase(item); |
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183 | |
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184 | state = heap.state(item); |
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185 | |
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186 | state = _Heap::PRE_HEAP; |
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187 | state = _Heap::IN_HEAP; |
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188 | state = _Heap::POST_HEAP; |
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189 | } |
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190 | |
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191 | _Heap& heap; |
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192 | ItemIntMap& map; |
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193 | |
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194 | Constraints() : heap(0), map(0) {} |
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195 | }; |
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196 | }; |
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197 | |
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198 | /// @} |
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199 | } // namespace lemon |
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200 | } |
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201 | #endif // LEMON_CONCEPT_PATH_H |
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