1 | /* -*- C++ -*- |
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2 | * |
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3 | * This file is a part of LEMON, a generic C++ optimization library |
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4 | * |
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5 | * Copyright (C) 2003-2006 |
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6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 | * |
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9 | * Permission to use, modify and distribute this software is granted |
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10 | * provided that this copyright notice appears in all copies. For |
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11 | * precise terms see the accompanying LICENSE file. |
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12 | * |
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13 | * This software is provided "AS IS" with no warranty of any kind, |
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14 | * express or implied, and with no claim as to its suitability for any |
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15 | * purpose. |
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16 | * |
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17 | */ |
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18 | |
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19 | #ifndef LEMON_LIST_GRAPH_H |
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20 | #define LEMON_LIST_GRAPH_H |
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21 | |
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22 | ///\ingroup graphs |
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23 | ///\file |
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24 | ///\brief ListGraph class. |
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25 | |
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26 | #include <lemon/bits/graph_extender.h> |
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27 | |
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28 | #include <vector> |
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29 | #include <list> |
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30 | |
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31 | namespace lemon { |
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32 | |
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33 | class ListGraphBase { |
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34 | |
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35 | protected: |
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36 | struct NodeT { |
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37 | int first_in, first_out; |
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38 | int prev, next; |
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39 | }; |
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40 | |
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41 | struct EdgeT { |
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42 | int target, source; |
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43 | int prev_in, prev_out; |
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44 | int next_in, next_out; |
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45 | }; |
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46 | |
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47 | std::vector<NodeT> nodes; |
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48 | |
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49 | int first_node; |
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50 | |
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51 | int first_free_node; |
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52 | |
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53 | std::vector<EdgeT> edges; |
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54 | |
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55 | int first_free_edge; |
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56 | |
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57 | public: |
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58 | |
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59 | typedef ListGraphBase Graph; |
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60 | |
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61 | class Node { |
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62 | friend class ListGraphBase; |
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63 | protected: |
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64 | |
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65 | int id; |
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66 | explicit Node(int pid) { id = pid;} |
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67 | |
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68 | public: |
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69 | Node() {} |
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70 | Node (Invalid) { id = -1; } |
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71 | bool operator==(const Node& node) const {return id == node.id;} |
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72 | bool operator!=(const Node& node) const {return id != node.id;} |
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73 | bool operator<(const Node& node) const {return id < node.id;} |
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74 | }; |
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75 | |
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76 | class Edge { |
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77 | friend class ListGraphBase; |
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78 | protected: |
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79 | |
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80 | int id; |
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81 | explicit Edge(int pid) { id = pid;} |
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82 | |
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83 | public: |
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84 | Edge() {} |
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85 | Edge (Invalid) { id = -1; } |
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86 | bool operator==(const Edge& edge) const {return id == edge.id;} |
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87 | bool operator!=(const Edge& edge) const {return id != edge.id;} |
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88 | bool operator<(const Edge& edge) const {return id < edge.id;} |
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89 | }; |
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90 | |
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91 | |
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92 | |
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93 | ListGraphBase() |
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94 | : nodes(), first_node(-1), |
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95 | first_free_node(-1), edges(), first_free_edge(-1) {} |
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96 | |
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97 | |
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98 | /// Maximum node ID. |
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99 | |
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100 | /// Maximum node ID. |
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101 | ///\sa id(Node) |
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102 | int maxNodeId() const { return nodes.size()-1; } |
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103 | |
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104 | /// Maximum edge ID. |
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105 | |
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106 | /// Maximum edge ID. |
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107 | ///\sa id(Edge) |
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108 | int maxEdgeId() const { return edges.size()-1; } |
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109 | |
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110 | Node source(Edge e) const { return Node(edges[e.id].source); } |
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111 | Node target(Edge e) const { return Node(edges[e.id].target); } |
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112 | |
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113 | |
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114 | void first(Node& node) const { |
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115 | node.id = first_node; |
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116 | } |
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117 | |
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118 | void next(Node& node) const { |
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119 | node.id = nodes[node.id].next; |
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120 | } |
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121 | |
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122 | |
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123 | void first(Edge& e) const { |
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124 | int n; |
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125 | for(n = first_node; |
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126 | n!=-1 && nodes[n].first_in == -1; |
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127 | n = nodes[n].next); |
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128 | e.id = (n == -1) ? -1 : nodes[n].first_in; |
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129 | } |
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130 | |
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131 | void next(Edge& edge) const { |
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132 | if (edges[edge.id].next_in != -1) { |
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133 | edge.id = edges[edge.id].next_in; |
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134 | } else { |
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135 | int n; |
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136 | for(n = nodes[edges[edge.id].target].next; |
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137 | n!=-1 && nodes[n].first_in == -1; |
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138 | n = nodes[n].next); |
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139 | edge.id = (n == -1) ? -1 : nodes[n].first_in; |
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140 | } |
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141 | } |
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142 | |
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143 | void firstOut(Edge &e, const Node& v) const { |
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144 | e.id = nodes[v.id].first_out; |
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145 | } |
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146 | void nextOut(Edge &e) const { |
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147 | e.id=edges[e.id].next_out; |
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148 | } |
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149 | |
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150 | void firstIn(Edge &e, const Node& v) const { |
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151 | e.id = nodes[v.id].first_in; |
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152 | } |
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153 | void nextIn(Edge &e) const { |
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154 | e.id=edges[e.id].next_in; |
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155 | } |
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156 | |
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157 | |
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158 | static int id(Node v) { return v.id; } |
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159 | static int id(Edge e) { return e.id; } |
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160 | |
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161 | static Node nodeFromId(int id) { return Node(id);} |
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162 | static Edge edgeFromId(int id) { return Edge(id);} |
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163 | |
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164 | /// Adds a new node to the graph. |
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165 | |
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166 | /// \warning It adds the new node to the front of the list. |
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167 | /// (i.e. the lastly added node becomes the first.) |
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168 | Node addNode() { |
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169 | int n; |
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170 | |
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171 | if(first_free_node==-1) { |
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172 | n = nodes.size(); |
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173 | nodes.push_back(NodeT()); |
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174 | } else { |
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175 | n = first_free_node; |
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176 | first_free_node = nodes[n].next; |
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177 | } |
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178 | |
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179 | nodes[n].next = first_node; |
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180 | if(first_node != -1) nodes[first_node].prev = n; |
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181 | first_node = n; |
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182 | nodes[n].prev = -1; |
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183 | |
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184 | nodes[n].first_in = nodes[n].first_out = -1; |
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185 | |
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186 | return Node(n); |
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187 | } |
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188 | |
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189 | Edge addEdge(Node u, Node v) { |
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190 | int n; |
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191 | |
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192 | if (first_free_edge == -1) { |
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193 | n = edges.size(); |
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194 | edges.push_back(EdgeT()); |
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195 | } else { |
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196 | n = first_free_edge; |
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197 | first_free_edge = edges[n].next_in; |
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198 | } |
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199 | |
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200 | edges[n].source = u.id; |
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201 | edges[n].target = v.id; |
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202 | |
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203 | edges[n].next_out = nodes[u.id].first_out; |
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204 | if(nodes[u.id].first_out != -1) { |
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205 | edges[nodes[u.id].first_out].prev_out = n; |
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206 | } |
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207 | |
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208 | edges[n].next_in = nodes[v.id].first_in; |
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209 | if(nodes[v.id].first_in != -1) { |
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210 | edges[nodes[v.id].first_in].prev_in = n; |
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211 | } |
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212 | |
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213 | edges[n].prev_in = edges[n].prev_out = -1; |
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214 | |
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215 | nodes[u.id].first_out = nodes[v.id].first_in = n; |
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216 | |
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217 | return Edge(n); |
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218 | } |
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219 | |
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220 | void erase(const Node& node) { |
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221 | int n = node.id; |
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222 | |
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223 | if(nodes[n].next != -1) { |
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224 | nodes[nodes[n].next].prev = nodes[n].prev; |
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225 | } |
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226 | |
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227 | if(nodes[n].prev != -1) { |
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228 | nodes[nodes[n].prev].next = nodes[n].next; |
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229 | } else { |
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230 | first_node = nodes[n].next; |
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231 | } |
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232 | |
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233 | nodes[n].next = first_free_node; |
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234 | first_free_node = n; |
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235 | |
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236 | } |
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237 | |
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238 | void erase(const Edge& edge) { |
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239 | int n = edge.id; |
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240 | |
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241 | if(edges[n].next_in!=-1) { |
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242 | edges[edges[n].next_in].prev_in = edges[n].prev_in; |
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243 | } |
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244 | |
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245 | if(edges[n].prev_in!=-1) { |
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246 | edges[edges[n].prev_in].next_in = edges[n].next_in; |
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247 | } else { |
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248 | nodes[edges[n].target].first_in = edges[n].next_in; |
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249 | } |
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250 | |
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251 | |
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252 | if(edges[n].next_out!=-1) { |
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253 | edges[edges[n].next_out].prev_out = edges[n].prev_out; |
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254 | } |
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255 | |
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256 | if(edges[n].prev_out!=-1) { |
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257 | edges[edges[n].prev_out].next_out = edges[n].next_out; |
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258 | } else { |
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259 | nodes[edges[n].source].first_out = edges[n].next_out; |
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260 | } |
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261 | |
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262 | edges[n].next_in = first_free_edge; |
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263 | first_free_edge = n; |
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264 | |
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265 | } |
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266 | |
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267 | void clear() { |
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268 | edges.clear(); |
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269 | nodes.clear(); |
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270 | first_node = first_free_node = first_free_edge = -1; |
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271 | } |
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272 | |
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273 | protected: |
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274 | void changeTarget(Edge e, Node n) |
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275 | { |
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276 | if(edges[e.id].next_in != -1) |
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277 | edges[edges[e.id].next_in].prev_in = edges[e.id].prev_in; |
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278 | if(edges[e.id].prev_in != -1) |
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279 | edges[edges[e.id].prev_in].next_in = edges[e.id].next_in; |
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280 | else nodes[edges[e.id].target].first_in = edges[e.id].next_in; |
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281 | if (nodes[n.id].first_in != -1) { |
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282 | edges[nodes[n.id].first_in].prev_in = e.id; |
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283 | } |
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284 | edges[e.id].target = n.id; |
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285 | edges[e.id].prev_in = -1; |
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286 | edges[e.id].next_in = nodes[n.id].first_in; |
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287 | nodes[n.id].first_in = e.id; |
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288 | } |
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289 | void changeSource(Edge e, Node n) |
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290 | { |
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291 | if(edges[e.id].next_out != -1) |
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292 | edges[edges[e.id].next_out].prev_out = edges[e.id].prev_out; |
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293 | if(edges[e.id].prev_out != -1) |
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294 | edges[edges[e.id].prev_out].next_out = edges[e.id].next_out; |
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295 | else nodes[edges[e.id].source].first_out = edges[e.id].next_out; |
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296 | if (nodes[n.id].first_out != -1) { |
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297 | edges[nodes[n.id].first_out].prev_out = e.id; |
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298 | } |
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299 | edges[e.id].source = n.id; |
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300 | edges[e.id].prev_out = -1; |
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301 | edges[e.id].next_out = nodes[n.id].first_out; |
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302 | nodes[n.id].first_out = e.id; |
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303 | } |
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304 | |
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305 | }; |
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306 | |
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307 | typedef GraphExtender<ListGraphBase> ExtendedListGraphBase; |
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308 | |
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309 | /// \ingroup graphs |
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310 | |
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311 | ///A list graph class. |
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312 | |
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313 | ///This is a simple and fast erasable graph implementation. |
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314 | /// |
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315 | ///It conforms to the \ref concept::Graph "Graph" concept and it |
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316 | ///also provides several additional useful extra functionalities. |
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317 | ///The most of the member functions and nested classes are |
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318 | ///documented only in the concept class. |
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319 | ///\sa concept::Graph. |
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320 | |
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321 | class ListGraph : public ExtendedListGraphBase { |
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322 | public: |
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323 | |
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324 | typedef ExtendedListGraphBase Parent; |
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325 | |
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326 | ///Add a new node to the graph. |
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327 | |
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328 | /// \return the new node. |
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329 | /// |
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330 | Node addNode() { return Parent::addNode(); } |
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331 | |
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332 | ///Add a new edge to the graph. |
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333 | |
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334 | ///Add a new edge to the graph with source node \c s |
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335 | ///and target node \c t. |
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336 | ///\return the new edge. |
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337 | Edge addEdge(const Node& s, const Node& t) { |
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338 | return Parent::addEdge(s, t); |
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339 | } |
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340 | |
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341 | /// Changes the target of \c e to \c n |
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342 | |
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343 | /// Changes the target of \c e to \c n |
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344 | /// |
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345 | ///\note The <tt>Edge</tt>s and <tt>OutEdgeIt</tt>s referencing |
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346 | ///the changed edge remain valid. However <tt>InEdgeIt</tt>s are |
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347 | ///invalidated. |
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348 | void changeTarget(Edge e, Node n) { |
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349 | Parent::changeTarget(e,n); |
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350 | } |
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351 | /// Changes the source of \c e to \c n |
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352 | |
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353 | /// Changes the source of \c e to \c n |
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354 | /// |
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355 | ///\note The <tt>Edge</tt>s and <tt>InEdgeIt</tt>s referencing |
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356 | ///the changed edge remain valid. However <tt>OutEdgeIt</tt>s are |
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357 | ///invalidated. |
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358 | void changeSource(Edge e, Node n) { |
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359 | Parent::changeSource(e,n); |
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360 | } |
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361 | |
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362 | /// Invert the direction of an edge. |
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363 | |
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364 | ///\note The <tt>Edge</tt>s referencing the changed edge remain |
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365 | ///valid. However <tt>OutEdgeIt</tt>s and <tt>InEdgeIt</tt>s are |
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366 | ///invalidated. |
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367 | void reverseEdge(Edge e) { |
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368 | Node t=target(e); |
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369 | changeTarget(e,source(e)); |
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370 | changeSource(e,t); |
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371 | } |
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372 | |
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373 | /// \brief Using this it is possible to avoid the superfluous memory |
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374 | /// allocation. |
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375 | |
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376 | ///Using this it is possible to avoid the superfluous memory |
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377 | ///allocation: if you know that the graph you want to build will |
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378 | ///contain at least 10 million nodes then it is worth to reserve |
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379 | ///space for this amount before starting to build the graph. |
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380 | void reserveNode(int n) { nodes.reserve(n); }; |
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381 | |
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382 | /// \brief Using this it is possible to avoid the superfluous memory |
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383 | /// allocation. |
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384 | |
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385 | ///Using this it is possible to avoid the superfluous memory |
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386 | ///allocation: see the \ref reserveNode function. |
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387 | void reserveEdge(int n) { edges.reserve(n); }; |
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388 | |
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389 | |
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390 | ///Contract two nodes. |
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391 | |
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392 | ///This function contracts two nodes. |
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393 | /// |
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394 | ///Node \p b will be removed but instead of deleting |
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395 | ///incident edges, they will be joined to \p a. |
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396 | ///The last parameter \p r controls whether to remove loops. \c true |
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397 | ///means that loops will be removed. |
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398 | /// |
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399 | ///\note The <tt>Edge</tt>s |
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400 | ///referencing a moved edge remain |
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401 | ///valid. However <tt>InEdge</tt>s and <tt>OutEdge</tt>s |
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402 | ///may be invalidated. |
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403 | void contract(Node a, Node b, bool r = true) |
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404 | { |
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405 | for(OutEdgeIt e(*this,b);e!=INVALID;) { |
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406 | OutEdgeIt f=e; |
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407 | ++f; |
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408 | if(r && target(e)==a) erase(e); |
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409 | else changeSource(e,a); |
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410 | e=f; |
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411 | } |
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412 | for(InEdgeIt e(*this,b);e!=INVALID;) { |
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413 | InEdgeIt f=e; |
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414 | ++f; |
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415 | if(r && source(e)==a) erase(e); |
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416 | else changeTarget(e,a); |
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417 | e=f; |
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418 | } |
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419 | erase(b); |
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420 | } |
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421 | |
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422 | ///Split a node. |
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423 | |
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424 | ///This function splits a node. First a new node is added to the graph, |
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425 | ///then the source of each outgoing edge of \c n is moved to this new node. |
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426 | ///If \c connect is \c true (this is the default value), then a new edge |
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427 | ///from \c n to the newly created node is also added. |
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428 | ///\return The newly created node. |
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429 | /// |
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430 | ///\note The <tt>Edge</tt>s |
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431 | ///referencing a moved edge remain |
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432 | ///valid. However <tt>InEdge</tt>s and <tt>OutEdge</tt>s |
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433 | ///may be invalidated. |
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434 | ///\warning This functionality cannot be used together with the Snapshot |
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435 | ///feature. |
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436 | ///\todo It could be implemented in a bit faster way. |
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437 | Node split(Node n, bool connect = true) { |
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438 | Node b = addNode(); |
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439 | for(OutEdgeIt e(*this,n);e!=INVALID;) { |
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440 | OutEdgeIt f=e; |
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441 | ++f; |
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442 | changeSource(e,b); |
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443 | e=f; |
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444 | } |
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445 | if (connect) addEdge(n,b); |
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446 | return b; |
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447 | } |
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448 | |
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449 | ///Split an edge. |
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450 | |
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451 | ///This function splits an edge. First a new node \c b is added to |
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452 | ///the graph, then the original edge is re-targeted to \c |
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453 | ///b. Finally an edge from \c b to the original target is added. |
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454 | ///\return The newly created node. |
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455 | ///\warning This functionality |
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456 | ///cannot be used together with the Snapshot feature. |
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457 | Node split(Edge e) { |
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458 | Node b = addNode(); |
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459 | addEdge(b,target(e)); |
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460 | changeTarget(e,b); |
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461 | return b; |
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462 | } |
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463 | |
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464 | /// \brief Class to make a snapshot of the graph and restore |
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465 | /// to it later. |
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466 | /// |
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467 | /// Class to make a snapshot of the graph and to restore it |
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468 | /// later. |
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469 | /// |
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470 | /// The newly added nodes and edges can be removed using the |
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471 | /// restore() function. |
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472 | /// |
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473 | /// \warning Edge and node deletions cannot be restored. |
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474 | class Snapshot { |
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475 | public: |
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476 | |
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477 | class UnsupportedOperation : public LogicError { |
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478 | public: |
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479 | virtual const char* exceptionName() const { |
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480 | return "lemon::ListGraph::Snapshot::UnsupportedOperation"; |
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481 | } |
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482 | }; |
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483 | |
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484 | |
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485 | protected: |
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486 | |
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487 | typedef Parent::NodeNotifier NodeNotifier; |
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488 | |
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489 | class NodeObserverProxy : public NodeNotifier::ObserverBase { |
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490 | public: |
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491 | |
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492 | NodeObserverProxy(Snapshot& _snapshot) |
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493 | : snapshot(_snapshot) {} |
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494 | |
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495 | using NodeNotifier::ObserverBase::attach; |
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496 | using NodeNotifier::ObserverBase::detach; |
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497 | using NodeNotifier::ObserverBase::attached; |
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498 | |
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499 | protected: |
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500 | |
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501 | virtual void add(const Node& node) { |
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502 | snapshot.addNode(node); |
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503 | } |
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504 | virtual void add(const std::vector<Node>& nodes) { |
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505 | for (int i = nodes.size() - 1; i >= 0; ++i) { |
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506 | snapshot.addNode(nodes[i]); |
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507 | } |
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508 | } |
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509 | virtual void erase(const Node& node) { |
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510 | snapshot.eraseNode(node); |
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511 | } |
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512 | virtual void erase(const std::vector<Node>& nodes) { |
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513 | for (int i = 0; i < (int)nodes.size(); ++i) { |
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514 | if (!snapshot.eraseNode(nodes[i])) break; |
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515 | } |
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516 | } |
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517 | virtual void build() { |
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518 | NodeNotifier* notifier = getNotifier(); |
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519 | Node node; |
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520 | std::vector<Node> nodes; |
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521 | for (notifier->first(node); node != INVALID; notifier->next(node)) { |
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522 | nodes.push_back(node); |
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523 | } |
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524 | for (int i = nodes.size() - 1; i >= 0; --i) { |
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525 | snapshot.addNode(nodes[i]); |
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526 | } |
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527 | } |
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528 | virtual void clear() { |
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529 | NodeNotifier* notifier = getNotifier(); |
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530 | Node node; |
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531 | for (notifier->first(node); node != INVALID; notifier->next(node)) { |
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532 | if (!snapshot.eraseNode(node)) break; |
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533 | } |
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534 | } |
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535 | |
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536 | Snapshot& snapshot; |
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537 | }; |
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538 | |
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539 | class EdgeObserverProxy : public EdgeNotifier::ObserverBase { |
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540 | public: |
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541 | |
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542 | EdgeObserverProxy(Snapshot& _snapshot) |
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543 | : snapshot(_snapshot) {} |
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544 | |
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545 | using EdgeNotifier::ObserverBase::attach; |
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546 | using EdgeNotifier::ObserverBase::detach; |
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547 | using EdgeNotifier::ObserverBase::attached; |
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548 | |
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549 | protected: |
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550 | |
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551 | virtual void add(const Edge& edge) { |
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552 | snapshot.addEdge(edge); |
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553 | } |
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554 | virtual void add(const std::vector<Edge>& edges) { |
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555 | for (int i = edges.size() - 1; i >= 0; ++i) { |
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556 | snapshot.addEdge(edges[i]); |
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557 | } |
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558 | } |
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559 | virtual void erase(const Edge& edge) { |
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560 | snapshot.eraseEdge(edge); |
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561 | } |
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562 | virtual void erase(const std::vector<Edge>& edges) { |
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563 | for (int i = 0; i < (int)edges.size(); ++i) { |
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564 | if (!snapshot.eraseEdge(edges[i])) break; |
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565 | } |
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566 | } |
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567 | virtual void build() { |
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568 | EdgeNotifier* notifier = getNotifier(); |
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569 | Edge edge; |
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570 | std::vector<Edge> edges; |
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571 | for (notifier->first(edge); edge != INVALID; notifier->next(edge)) { |
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572 | edges.push_back(edge); |
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573 | } |
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574 | for (int i = edges.size() - 1; i >= 0; --i) { |
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575 | snapshot.addEdge(edges[i]); |
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576 | } |
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577 | } |
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578 | virtual void clear() { |
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579 | EdgeNotifier* notifier = getNotifier(); |
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580 | Edge edge; |
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581 | for (notifier->first(edge); edge != INVALID; notifier->next(edge)) { |
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582 | if (!snapshot.eraseEdge(edge)) break; |
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583 | } |
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584 | } |
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585 | |
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586 | Snapshot& snapshot; |
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587 | }; |
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588 | |
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589 | ListGraph *graph; |
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590 | |
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591 | NodeObserverProxy node_observer_proxy; |
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592 | EdgeObserverProxy edge_observer_proxy; |
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593 | |
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594 | std::list<Node> added_nodes; |
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595 | std::list<Edge> added_edges; |
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596 | |
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597 | |
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598 | void addNode(const Node& node) { |
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599 | added_nodes.push_front(node); |
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600 | } |
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601 | bool eraseNode(const Node& node) { |
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602 | std::list<Node>::iterator it = |
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603 | std::find(added_nodes.begin(), added_nodes.end(), node); |
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604 | if (it == added_nodes.end()) { |
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605 | clear(); |
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606 | return false; |
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607 | } else { |
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608 | added_nodes.erase(it); |
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609 | return true; |
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610 | } |
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611 | } |
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612 | |
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613 | void addEdge(const Edge& edge) { |
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614 | added_edges.push_front(edge); |
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615 | } |
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616 | bool eraseEdge(const Edge& edge) { |
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617 | std::list<Edge>::iterator it = |
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618 | std::find(added_edges.begin(), added_edges.end(), edge); |
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619 | if (it == added_edges.end()) { |
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620 | clear(); |
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621 | return false; |
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622 | } else { |
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623 | added_edges.erase(it); |
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624 | return true; |
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625 | } |
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626 | } |
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627 | |
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628 | void attach(ListGraph &_graph) { |
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629 | graph = &_graph; |
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630 | node_observer_proxy.attach(graph->getNotifier(Node())); |
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631 | edge_observer_proxy.attach(graph->getNotifier(Edge())); |
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632 | } |
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633 | |
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634 | void detach() { |
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635 | node_observer_proxy.detach(); |
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636 | edge_observer_proxy.detach(); |
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637 | } |
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638 | |
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639 | void clear() { |
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640 | detach(); |
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641 | added_nodes.clear(); |
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642 | added_edges.clear(); |
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643 | } |
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644 | |
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645 | public: |
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646 | |
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647 | /// \brief Default constructur. |
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648 | /// |
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649 | /// Default constructor. |
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650 | /// To actually make a snapshot you must call save(). |
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651 | Snapshot() |
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652 | : graph(0), node_observer_proxy(*this), |
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653 | edge_observer_proxy(*this) {} |
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654 | |
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655 | /// \brief Constructor that immediately makes a snapshot. |
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656 | /// |
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657 | /// This constructor immediately makes a snapshot of the graph. |
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658 | /// \param _graph The graph we make a snapshot of. |
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659 | Snapshot(ListGraph &_graph) |
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660 | : node_observer_proxy(*this), |
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661 | edge_observer_proxy(*this) { |
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662 | attach(_graph); |
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663 | } |
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664 | |
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665 | /// \brief Make a snapshot. |
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666 | /// |
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667 | /// Make a snapshot of the graph. |
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668 | /// |
---|
669 | /// This function can be called more than once. In case of a repeated |
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670 | /// call, the previous snapshot gets lost. |
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671 | /// \param _graph The graph we make the snapshot of. |
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672 | void save(ListGraph &_graph) { |
---|
673 | clear(); |
---|
674 | attach(_graph); |
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675 | } |
---|
676 | |
---|
677 | /// \brief Undo the changes until the last snapshot. |
---|
678 | // |
---|
679 | /// Undo the changes until last snapshot created by save(). |
---|
680 | /// |
---|
681 | /// \todo This function might be called undo(). |
---|
682 | void restore() { |
---|
683 | detach(); |
---|
684 | while(!added_edges.empty()) { |
---|
685 | graph->erase(added_edges.front()); |
---|
686 | added_edges.pop_front(); |
---|
687 | } |
---|
688 | while(!added_nodes.empty()) { |
---|
689 | graph->erase(added_nodes.front()); |
---|
690 | added_nodes.pop_front(); |
---|
691 | } |
---|
692 | } |
---|
693 | |
---|
694 | /// \brief Gives back true when the snapshot is valid. |
---|
695 | /// |
---|
696 | /// Gives back true when the snapshot is valid. |
---|
697 | bool valid() const { |
---|
698 | return node_observer_proxy.attached(); |
---|
699 | } |
---|
700 | }; |
---|
701 | |
---|
702 | }; |
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703 | |
---|
704 | } //namespace lemon |
---|
705 | |
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706 | |
---|
707 | #endif |
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