1 | /* -*- C++ -*- |
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2 | * src/lemon/list_graph.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 | #ifndef LEMON_LIST_GRAPH_H |
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18 | #define LEMON_LIST_GRAPH_H |
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19 | |
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20 | ///\ingroup graphs |
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21 | ///\file |
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22 | ///\brief ListGraph, SymListGraph classes. |
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23 | |
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24 | #include <lemon/bits/erasable_graph_extender.h> |
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25 | #include <lemon/bits/clearable_graph_extender.h> |
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26 | #include <lemon/bits/extendable_graph_extender.h> |
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27 | #include <lemon/bits/iterable_graph_extender.h> |
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28 | #include <lemon/bits/alteration_notifier.h> |
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29 | #include <lemon/bits/default_map.h> |
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30 | |
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31 | #include <lemon/bits/undir_graph_extender.h> |
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32 | |
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33 | #include <list> |
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34 | |
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35 | namespace lemon { |
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36 | |
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37 | class ListGraphBase { |
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38 | |
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39 | protected: |
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40 | struct NodeT { |
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41 | int first_in,first_out; |
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42 | int prev, next; |
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43 | }; |
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44 | |
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45 | struct EdgeT { |
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46 | int target, source; |
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47 | int prev_in, prev_out; |
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48 | int next_in, next_out; |
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49 | }; |
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50 | |
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51 | std::vector<NodeT> nodes; |
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52 | |
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53 | int first_node; |
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54 | |
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55 | int first_free_node; |
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56 | |
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57 | std::vector<EdgeT> edges; |
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58 | |
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59 | int first_free_edge; |
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60 | |
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61 | public: |
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62 | |
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63 | typedef ListGraphBase Graph; |
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64 | |
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65 | class Node { |
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66 | friend class ListGraphBase; |
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67 | protected: |
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68 | |
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69 | int id; |
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70 | Node(int pid) { id = pid;} |
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71 | |
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72 | public: |
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73 | Node() {} |
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74 | Node (Invalid) { id = -1; } |
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75 | bool operator==(const Node& node) const {return id == node.id;} |
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76 | bool operator!=(const Node& node) const {return id != node.id;} |
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77 | bool operator<(const Node& node) const {return id < node.id;} |
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78 | }; |
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79 | |
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80 | class Edge { |
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81 | friend class ListGraphBase; |
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82 | protected: |
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83 | |
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84 | int id; |
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85 | Edge(int pid) { id = pid;} |
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86 | |
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87 | public: |
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88 | Edge() {} |
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89 | Edge (Invalid) { id = -1; } |
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90 | bool operator==(const Edge& edge) const {return id == edge.id;} |
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91 | bool operator!=(const Edge& edge) const {return id != edge.id;} |
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92 | bool operator<(const Edge& edge) const {return id < edge.id;} |
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93 | }; |
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94 | |
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95 | |
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96 | |
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97 | ListGraphBase() |
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98 | : nodes(), first_node(-1), |
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99 | first_free_node(-1), edges(), first_free_edge(-1) {} |
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100 | |
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101 | |
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102 | /// Maximum node ID. |
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103 | |
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104 | /// Maximum node ID. |
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105 | ///\sa id(Node) |
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106 | int maxId(Node = INVALID) const { return nodes.size()-1; } |
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107 | |
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108 | /// Maximum edge ID. |
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109 | |
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110 | /// Maximum edge ID. |
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111 | ///\sa id(Edge) |
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112 | int maxId(Edge = INVALID) const { return edges.size()-1; } |
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113 | |
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114 | Node source(Edge e) const { return edges[e.id].source; } |
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115 | Node target(Edge e) const { return edges[e.id].target; } |
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116 | |
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117 | |
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118 | void first(Node& node) const { |
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119 | node.id = first_node; |
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120 | } |
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121 | |
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122 | void next(Node& node) const { |
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123 | node.id = nodes[node.id].next; |
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124 | } |
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125 | |
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126 | |
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127 | void first(Edge& e) const { |
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128 | int n; |
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129 | for(n = first_node; |
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130 | n!=-1 && nodes[n].first_in == -1; |
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131 | n = nodes[n].next); |
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132 | e.id = (n == -1) ? -1 : nodes[n].first_in; |
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133 | } |
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134 | |
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135 | void next(Edge& edge) const { |
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136 | if (edges[edge.id].next_in != -1) { |
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137 | edge.id = edges[edge.id].next_in; |
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138 | } else { |
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139 | int n; |
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140 | for(n = nodes[edges[edge.id].target].next; |
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141 | n!=-1 && nodes[n].first_in == -1; |
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142 | n = nodes[n].next); |
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143 | edge.id = (n == -1) ? -1 : nodes[n].first_in; |
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144 | } |
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145 | } |
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146 | |
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147 | void firstOut(Edge &e, const Node& v) const { |
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148 | e.id = nodes[v.id].first_out; |
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149 | } |
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150 | void nextOut(Edge &e) const { |
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151 | e.id=edges[e.id].next_out; |
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152 | } |
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153 | |
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154 | void firstIn(Edge &e, const Node& v) const { |
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155 | e.id = nodes[v.id].first_in; |
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156 | } |
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157 | void nextIn(Edge &e) const { |
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158 | e.id=edges[e.id].next_in; |
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159 | } |
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160 | |
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161 | |
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162 | static int id(Node v) { return v.id; } |
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163 | static int id(Edge e) { return e.id; } |
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164 | |
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165 | static Node fromId(int id, Node) { return Node(id);} |
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166 | static Edge fromId(int id, Edge) { return Edge(id);} |
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167 | |
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168 | /// Adds a new node to the graph. |
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169 | |
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170 | /// \warning It adds the new node to the front of the list. |
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171 | /// (i.e. the lastly added node becomes the first.) |
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172 | Node addNode() { |
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173 | int n; |
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174 | |
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175 | if(first_free_node==-1) { |
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176 | n = nodes.size(); |
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177 | nodes.push_back(NodeT()); |
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178 | } else { |
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179 | n = first_free_node; |
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180 | first_free_node = nodes[n].next; |
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181 | } |
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182 | |
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183 | nodes[n].next = first_node; |
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184 | if(first_node != -1) nodes[first_node].prev = n; |
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185 | first_node = n; |
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186 | nodes[n].prev = -1; |
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187 | |
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188 | nodes[n].first_in = nodes[n].first_out = -1; |
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189 | |
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190 | return Node(n); |
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191 | } |
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192 | |
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193 | Edge addEdge(Node u, Node v) { |
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194 | int n; |
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195 | |
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196 | if (first_free_edge == -1) { |
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197 | n = edges.size(); |
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198 | edges.push_back(EdgeT()); |
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199 | } else { |
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200 | n = first_free_edge; |
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201 | first_free_edge = edges[n].next_in; |
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202 | } |
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203 | |
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204 | edges[n].source = u.id; |
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205 | edges[n].target = v.id; |
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206 | |
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207 | edges[n].next_out = nodes[u.id].first_out; |
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208 | if(nodes[u.id].first_out != -1) { |
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209 | edges[nodes[u.id].first_out].prev_out = n; |
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210 | } |
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211 | |
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212 | edges[n].next_in = nodes[v.id].first_in; |
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213 | if(nodes[v.id].first_in != -1) { |
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214 | edges[nodes[v.id].first_in].prev_in = n; |
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215 | } |
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216 | |
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217 | edges[n].prev_in = edges[n].prev_out = -1; |
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218 | |
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219 | nodes[u.id].first_out = nodes[v.id].first_in = n; |
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220 | |
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221 | return Edge(n); |
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222 | } |
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223 | |
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224 | void erase(const Node& node) { |
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225 | int n = node.id; |
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226 | |
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227 | if(nodes[n].next != -1) { |
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228 | nodes[nodes[n].next].prev = nodes[n].prev; |
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229 | } |
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230 | |
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231 | if(nodes[n].prev != -1) { |
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232 | nodes[nodes[n].prev].next = nodes[n].next; |
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233 | } else { |
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234 | first_node = nodes[n].next; |
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235 | } |
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236 | |
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237 | nodes[n].next = first_free_node; |
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238 | first_free_node = n; |
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239 | |
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240 | } |
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241 | |
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242 | void erase(const Edge& edge) { |
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243 | int n = edge.id; |
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244 | |
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245 | if(edges[n].next_in!=-1) { |
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246 | edges[edges[n].next_in].prev_in = edges[n].prev_in; |
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247 | } |
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248 | |
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249 | if(edges[n].prev_in!=-1) { |
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250 | edges[edges[n].prev_in].next_in = edges[n].next_in; |
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251 | } else { |
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252 | nodes[edges[n].target].first_in = edges[n].next_in; |
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253 | } |
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254 | |
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255 | |
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256 | if(edges[n].next_out!=-1) { |
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257 | edges[edges[n].next_out].prev_out = edges[n].prev_out; |
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258 | } |
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259 | |
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260 | if(edges[n].prev_out!=-1) { |
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261 | edges[edges[n].prev_out].next_out = edges[n].next_out; |
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262 | } else { |
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263 | nodes[edges[n].source].first_out = edges[n].next_out; |
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264 | } |
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265 | |
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266 | edges[n].next_in = first_free_edge; |
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267 | first_free_edge = n; |
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268 | |
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269 | } |
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270 | |
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271 | void clear() { |
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272 | edges.clear(); |
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273 | nodes.clear(); |
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274 | first_node = first_free_node = first_free_edge = -1; |
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275 | } |
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276 | |
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277 | protected: |
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278 | void _moveTarget(Edge e, Node n) |
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279 | { |
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280 | if(edges[e.id].next_in != -1) |
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281 | edges[edges[e.id].next_in].prev_in = edges[e.id].prev_in; |
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282 | if(edges[e.id].prev_in != -1) |
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283 | edges[edges[e.id].prev_in].next_in = edges[e.id].next_in; |
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284 | else nodes[edges[e.id].target].first_in = edges[e.id].next_in; |
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285 | edges[e.id].target = n.id; |
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286 | edges[e.id].prev_in = -1; |
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287 | edges[e.id].next_in = nodes[n.id].first_in; |
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288 | nodes[n.id].first_in = e.id; |
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289 | } |
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290 | void _moveSource(Edge e, Node n) |
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291 | { |
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292 | if(edges[e.id].next_out != -1) |
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293 | edges[edges[e.id].next_out].prev_out = edges[e.id].prev_out; |
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294 | if(edges[e.id].prev_out != -1) |
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295 | edges[edges[e.id].prev_out].next_out = edges[e.id].next_out; |
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296 | else nodes[edges[e.id].source].first_out = edges[e.id].next_out; |
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297 | edges[e.id].source = n.id; |
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298 | edges[e.id].prev_out = -1; |
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299 | edges[e.id].next_out = nodes[n.id].first_out; |
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300 | nodes[n.id].first_out = e.id; |
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301 | } |
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302 | |
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303 | }; |
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304 | |
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305 | typedef AlterableGraphExtender<ListGraphBase> AlterableListGraphBase; |
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306 | typedef IterableGraphExtender<AlterableListGraphBase> IterableListGraphBase; |
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307 | typedef DefaultMappableGraphExtender<IterableListGraphBase> MappableListGraphBase; |
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308 | typedef ExtendableGraphExtender<MappableListGraphBase> ExtendableListGraphBase; |
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309 | typedef ClearableGraphExtender<ExtendableListGraphBase> ClearableListGraphBase; |
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310 | typedef ErasableGraphExtender<ClearableListGraphBase> ErasableListGraphBase; |
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311 | |
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312 | /// \addtogroup graphs |
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313 | /// @{ |
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314 | |
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315 | ///A list graph class. |
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316 | |
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317 | ///This is a simple and fast erasable graph implementation. |
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318 | /// |
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319 | ///It addition that it conforms to the |
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320 | ///\ref concept::ErasableGraph "ErasableGraph" concept, |
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321 | ///it also provides several additional useful extra functionalities. |
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322 | ///\sa concept::ErasableGraph. |
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323 | |
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324 | class ListGraph : public ErasableListGraphBase |
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325 | { |
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326 | public: |
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327 | /// Moves the target of \c e to \c n |
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328 | |
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329 | /// Moves the target of \c e to \c n |
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330 | /// |
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331 | ///\note The <tt>Edge</tt>'s and <tt>OutEdge</tt>'s |
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332 | ///referencing the moved edge remain |
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333 | ///valid. However <tt>InEdge</tt>'s are invalidated. |
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334 | void moveTarget(Edge e, Node n) { _moveTarget(e,n); } |
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335 | /// Moves the source of \c e to \c n |
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336 | |
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337 | /// Moves the source of \c e to \c n |
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338 | /// |
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339 | ///\note The <tt>Edge</tt>'s and <tt>InEdge</tt>'s |
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340 | ///referencing the moved edge remain |
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341 | ///valid. However <tt>OutEdge</tt>'s are invalidated. |
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342 | void moveSource(Edge e, Node n) { _moveSource(e,n); } |
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343 | |
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344 | /// Invert the direction of an edge. |
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345 | |
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346 | ///\note The <tt>Edge</tt>'s |
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347 | ///referencing the moved edge remain |
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348 | ///valid. However <tt>OutEdge</tt>'s and <tt>InEdge</tt>'s are invalidated. |
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349 | void reverseEdge(Edge e) { |
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350 | Node t=target(e); |
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351 | _moveTarget(e,source(e)); |
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352 | _moveSource(e,t); |
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353 | } |
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354 | |
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355 | ///Using this it possible to avoid the superfluous memory allocation. |
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356 | |
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357 | ///Using this it possible to avoid the superfluous memory allocation. |
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358 | ///\todo more docs... |
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359 | void reserveEdge(int n) { edges.reserve(n); }; |
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360 | |
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361 | ///Contract two nodes. |
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362 | |
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363 | ///This function contracts two nodes. |
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364 | /// |
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365 | ///Node \p b will be removed but instead of deleting |
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366 | ///its neighboring edges, they will be joined to \p a. |
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367 | ///The last parameter \p r controls whether to remove loops. \c true |
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368 | ///means that loops will be removed. |
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369 | /// |
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370 | ///\note The <tt>Edge</tt>s |
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371 | ///referencing a moved edge remain |
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372 | ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s |
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373 | ///may be invalidated. |
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374 | void contract(Node a,Node b,bool r=true) |
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375 | { |
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376 | for(OutEdgeIt e(*this,b);e!=INVALID;) { |
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377 | OutEdgeIt f=e; |
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378 | ++f; |
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379 | if(r && target(e)==a) erase(e); |
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380 | else moveSource(e,a); |
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381 | e=f; |
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382 | } |
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383 | for(InEdgeIt e(*this,b);e!=INVALID;) { |
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384 | InEdgeIt f=e; |
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385 | ++f; |
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386 | if(r && source(e)==a) erase(e); |
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387 | else moveTarget(e,a); |
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388 | e=f; |
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389 | } |
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390 | erase(b); |
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391 | } |
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392 | |
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393 | ///Split a node. |
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394 | |
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395 | ///This function splits a node. First a new node is added to the graph, |
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396 | ///then the source of each outgoing edge of \c n is moved to this new node. |
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397 | ///If \c connect is \c true (this is the default value), then a new edge |
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398 | ///from \c n to the newly created node is also added. |
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399 | ///\return The newly created node. |
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400 | /// |
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401 | ///\note The <tt>Edge</tt>s |
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402 | ///referencing a moved edge remain |
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403 | ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s |
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404 | ///may be invalidated. |
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405 | ///\warning This functionality cannot be used together with the SnapShot |
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406 | ///feature. |
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407 | ///\todo It could be implemented in a bit faster way. |
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408 | Node split(Node n, bool connect = true) |
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409 | { |
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410 | Node b = addNode(); |
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411 | for(OutEdgeIt e(*this,n);e!=INVALID;) { |
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412 | OutEdgeIt f=e; |
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413 | ++f; |
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414 | moveSource(e,b); |
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415 | e=f; |
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416 | } |
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417 | if(connect) addEdge(n,b); |
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418 | return b; |
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419 | } |
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420 | |
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421 | ///Class to make a snapshot of the graph and to restrore to it later. |
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422 | |
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423 | ///Class to make a snapshot of the graph and to restrore to it later. |
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424 | /// |
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425 | ///The newly added nodes and edges can be removed using the |
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426 | ///restore() function. |
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427 | /// |
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428 | ///\warning Edge and node deletions cannot be restored. |
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429 | ///\warning SnapShots cannot be nested. |
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430 | ///\todo \c SnapShot or \c Snapshot? |
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431 | class SnapShot : protected AlterationNotifier<Node>::ObserverBase, |
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432 | protected AlterationNotifier<Edge>::ObserverBase |
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433 | { |
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434 | protected: |
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435 | |
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436 | ListGraph *g; |
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437 | std::list<Node> added_nodes; |
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438 | std::list<Edge> added_edges; |
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439 | |
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440 | bool active; |
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441 | virtual void add(const Node& n) { |
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442 | added_nodes.push_back(n); |
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443 | }; |
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444 | ///\bug Exception... |
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445 | /// |
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446 | virtual void erase(const Node&) |
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447 | { |
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448 | exit(1); |
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449 | } |
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450 | virtual void add(const Edge& n) { |
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451 | added_edges.push_back(n); |
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452 | }; |
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453 | ///\bug Exception... |
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454 | /// |
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455 | virtual void erase(const Edge&) |
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456 | { |
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457 | exit(1); |
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458 | } |
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459 | |
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460 | void regist(ListGraph &_g) { |
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461 | g=&_g; |
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462 | AlterationNotifier<Node>::ObserverBase:: |
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463 | attach(g->getNotifier(Node())); |
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464 | AlterationNotifier<Edge>::ObserverBase:: |
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465 | attach(g->getNotifier(Edge())); |
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466 | } |
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467 | |
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468 | void deregist() { |
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469 | AlterationNotifier<Node>::ObserverBase:: |
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470 | detach(); |
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471 | AlterationNotifier<Edge>::ObserverBase:: |
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472 | detach(); |
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473 | g=0; |
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474 | } |
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475 | |
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476 | public: |
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477 | ///Default constructur. |
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478 | |
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479 | ///Default constructur. |
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480 | ///To actually make a snapshot you must call save(). |
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481 | /// |
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482 | SnapShot() : g(0) {} |
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483 | ///Constructor that immediately makes a snapshot. |
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484 | |
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485 | ///This constructor immediately makes a snapshot of the graph. |
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486 | ///\param _g The graph we make a snapshot of. |
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487 | SnapShot(ListGraph &_g) { |
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488 | regist(_g); |
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489 | } |
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490 | ///\bug Is it necessary? |
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491 | /// |
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492 | ~SnapShot() |
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493 | { |
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494 | if(g) deregist(); |
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495 | } |
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496 | |
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497 | ///Make a snapshot. |
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498 | |
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499 | ///Make a snapshot of the graph. |
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500 | /// |
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501 | ///This function can be called more than once. In case of a repeated |
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502 | ///call, the previous snapshot gets lost. |
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503 | ///\param _g The graph we make the snapshot of. |
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504 | void save(ListGraph &_g) |
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505 | { |
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506 | if(g!=&_g) { |
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507 | if(g) deregist(); |
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508 | regist(_g); |
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509 | } |
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510 | added_nodes.clear(); |
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511 | added_edges.clear(); |
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512 | } |
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513 | |
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514 | ///Undo the changes until the last snapshot. |
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515 | |
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516 | ///Undo the changes until last snapshot created by save(). |
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517 | /// |
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518 | ///\todo This function might be called undo(). |
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519 | void restore() { |
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520 | deregist(); |
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521 | while(!added_edges.empty()) { |
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522 | g->erase(added_edges.front()); |
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523 | added_edges.pop_front(); |
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524 | } |
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525 | while(!added_nodes.empty()) { |
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526 | g->erase(added_nodes.front()); |
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527 | added_nodes.pop_front(); |
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528 | } |
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529 | } |
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530 | }; |
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531 | |
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532 | }; |
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533 | |
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534 | |
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535 | /**************** Undirected List Graph ****************/ |
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536 | |
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537 | typedef ErasableUndirGraphExtender< |
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538 | ClearableUndirGraphExtender< |
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539 | ExtendableUndirGraphExtender< |
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540 | MappableUndirGraphExtender< |
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541 | IterableUndirGraphExtender< |
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542 | AlterableUndirGraphExtender< |
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543 | UndirGraphExtender<ListGraphBase> > > > > > > ErasableUndirListGraphBase; |
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544 | |
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545 | ///An undirected list graph class. |
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546 | |
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547 | ///This is a simple and fast erasable undirected graph implementation. |
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548 | /// |
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549 | ///It conforms to the |
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550 | ///\ref concept::UndirGraph "UndirGraph" concept. |
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551 | /// |
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552 | ///\sa concept::UndirGraph. |
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553 | /// |
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554 | ///\todo SnapShot, reverseEdge(), moveTarget(), moveSource(), contract() |
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555 | ///haven't been implemented yet. |
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556 | /// |
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557 | class UndirListGraph : public ErasableUndirListGraphBase { |
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558 | }; |
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559 | |
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560 | |
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561 | /// @} |
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562 | } //namespace lemon |
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563 | |
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564 | |
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565 | #endif |
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