1 | /* -*- C++ -*- |
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2 | * |
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3 | * src/lemon/undir_graph_extender.h - Part of LEMON, a generic C++ |
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4 | * optimization library |
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5 | * |
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6 | * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi |
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7 | * Kutatocsoport (Egervary Combinatorial Optimization Research Group, |
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8 | * EGRES). |
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9 | * |
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10 | * Permission to use, modify and distribute this software is granted |
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11 | * provided that this copyright notice appears in all copies. For |
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12 | * precise terms see the accompanying LICENSE file. |
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13 | * |
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14 | * This software is provided "AS IS" with no warranty of any kind, |
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15 | * express or implied, and with no claim as to its suitability for any |
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16 | * purpose. |
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17 | * |
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18 | */ |
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19 | |
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20 | #ifndef LEMON_UNDIR_GRAPH_EXTENDER_H |
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21 | #define LEMON_UNDIR_GRAPH_EXTENDER_H |
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22 | |
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23 | #include <lemon/invalid.h> |
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24 | |
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25 | namespace lemon { |
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26 | |
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27 | template <typename _Base> |
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28 | class UndirGraphExtender : public _Base { |
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29 | typedef _Base Parent; |
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30 | typedef UndirGraphExtender Graph; |
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31 | |
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32 | public: |
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33 | |
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34 | typedef typename Parent::Edge UndirEdge; |
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35 | typedef typename Parent::Node Node; |
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36 | |
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37 | class Edge : public UndirEdge { |
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38 | friend class Graph; |
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39 | |
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40 | protected: |
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41 | // FIXME: Marci use opposite logic in his graph wrappers. It would |
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42 | // be reasonable to syncronize... |
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43 | bool forward; |
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44 | |
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45 | public: |
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46 | Edge() {} |
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47 | /// Construct a direct edge from undirect edge and a direction. |
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48 | Edge(const UndirEdge &ue, bool _forward) : |
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49 | UndirEdge(ue), forward(_forward) {} |
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50 | /// Invalid edge constructor |
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51 | Edge(Invalid i) : UndirEdge(i), forward(false) {} |
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52 | |
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53 | bool operator==(const Edge &that) const { |
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54 | return forward==that.forward && UndirEdge(*this)==UndirEdge(that); |
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55 | } |
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56 | bool operator!=(const Edge &that) const { |
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57 | return forward!=that.forward || UndirEdge(*this)!=UndirEdge(that); |
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58 | } |
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59 | bool operator<(const Edge &that) const { |
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60 | return forward<that.forward || |
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61 | (!(that.forward<forward) && UndirEdge(*this)<UndirEdge(that)); |
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62 | } |
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63 | }; |
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64 | |
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65 | |
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66 | /// \brief Returns the Edge of opposite direction. |
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67 | /// |
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68 | /// \bug Is this a good name for this? Or "reverse" is better? |
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69 | Edge opposite(const Edge &e) const { |
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70 | return Edge(e,!e.forward); |
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71 | } |
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72 | |
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73 | /// Tail of the given Edge. |
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74 | Node tail(const Edge &e) const { |
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75 | return e.forward ? Parent::tail(e) : Parent::head(e); |
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76 | } |
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77 | |
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78 | /// \todo Shouldn't the "tail" of an undirected edge be called "aNode" |
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79 | /// or something??? |
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80 | using Parent::tail; |
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81 | |
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82 | /// Head of the given Edge. |
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83 | Node head(const Edge &e) const { |
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84 | return e.forward ? Parent::head(e) : Parent::tail(e); |
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85 | } |
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86 | |
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87 | /// \todo Shouldn't the "head" of an undirected edge be called "bNode" |
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88 | /// or something??? |
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89 | using Parent::head; |
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90 | |
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91 | /// Returns whether the given directed edge is same orientation as the |
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92 | /// corresponding undirected edge. |
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93 | /// |
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94 | /// \todo reference to the corresponding point of the undirected graph |
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95 | /// concept. "What does the direction of an undirected edge mean?" |
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96 | bool forward(const Edge &e) const { return e.forward; } |
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97 | |
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98 | Node oppsiteNode(const Node &n, const Edge &e) const { |
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99 | if( n == Parent::tail(e)) |
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100 | return Parent::head(e); |
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101 | else if( n == Parent::head(e)) |
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102 | return Parent::tail(e); |
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103 | else |
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104 | return INVALID; |
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105 | } |
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106 | |
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107 | |
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108 | using Parent::first; |
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109 | void first(Edge &e) const { |
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110 | Parent::first(e); |
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111 | e.forward=true; |
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112 | } |
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113 | |
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114 | using Parent::next; |
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115 | void next(Edge &e) const { |
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116 | if( e.forward ) { |
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117 | e.forward = false; |
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118 | } |
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119 | else { |
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120 | Parent::next(e); |
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121 | e.forward = true; |
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122 | } |
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123 | } |
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124 | |
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125 | void firstOut(Edge &e, const Node &n) const { |
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126 | Parent::firstOut(e,n); |
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127 | if( UndirEdge(e) != INVALID ) { |
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128 | e.forward = true; |
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129 | } |
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130 | else { |
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131 | Parent::firstIn(e,n); |
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132 | e.forward = false; |
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133 | } |
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134 | } |
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135 | void firstIn(Edge &e, const Node &n) const { |
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136 | Parent::firstIn(e,n); |
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137 | if( UndirEdge(e) != INVALID ) { |
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138 | e.forward = true; |
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139 | } |
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140 | else { |
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141 | Parent::firstOut(e,n); |
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142 | e.forward = false; |
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143 | } |
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144 | } |
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145 | |
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146 | void nextOut(Edge &e) const { |
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147 | if( e.forward ) { |
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148 | Parent::nextOut(e); |
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149 | if( UndirEdge(e) == INVALID ) { |
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150 | Parent::firstIn(e, Parent::tail(e)); |
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151 | e.forward = false; |
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152 | } |
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153 | } |
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154 | else { |
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155 | Parent::nextIn(e); |
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156 | } |
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157 | } |
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158 | void nextIn(Edge &e) const { |
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159 | if( e.forward ) { |
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160 | Parent::nextIn(e); |
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161 | if( UndirEdge(e) == INVALID ) { |
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162 | Parent::firstOut(e, Parent::head(e)); |
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163 | e.forward = false; |
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164 | } |
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165 | } |
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166 | else { |
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167 | Parent::nextOut(e); |
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168 | } |
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169 | } |
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170 | |
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171 | // Miscellaneous stuff: |
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172 | |
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173 | /// \todo these methods (id, maxEdgeId) should be moved into separate |
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174 | /// Extender |
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175 | |
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176 | using Parent::id; |
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177 | |
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178 | int id(const Edge &e) const { |
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179 | return 2*Parent::id(e) + int(e.forward); |
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180 | } |
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181 | |
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182 | int maxEdgeId() const { |
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183 | return 2*Parent::maxEdgeId() + 1; |
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184 | } |
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185 | int maxUndirEdgeId() const { |
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186 | return Parent::maxEdgeId(); |
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187 | } |
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188 | |
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189 | }; |
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190 | |
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191 | } |
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192 | |
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193 | #endif // LEMON_UNDIR_GRAPH_EXTENDER_H |
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