1 | /* -*- C++ -*- |
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2 | * lemon/smart_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_SMART_GRAPH_H |
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18 | #define LEMON_SMART_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 SmartGraph and UndirSmartGraph classes. |
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23 | |
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24 | #include <vector> |
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25 | |
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26 | #include <lemon/invalid.h> |
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27 | |
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28 | #include <lemon/bits/clearable_graph_extender.h> |
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29 | #include <lemon/bits/extendable_graph_extender.h> |
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30 | #include <lemon/bits/iterable_graph_extender.h> |
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31 | #include <lemon/bits/alteration_notifier.h> |
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32 | #include <lemon/bits/default_map.h> |
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33 | |
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34 | #include <lemon/bits/undir_graph_extender.h> |
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35 | |
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36 | #include <lemon/utility.h> |
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37 | |
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38 | namespace lemon { |
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39 | |
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40 | class SmartGraph; |
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41 | ///Base of SmartGraph |
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42 | |
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43 | ///Base of SmartGraph |
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44 | /// |
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45 | class SmartGraphBase { |
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46 | |
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47 | friend class SmatGraph; |
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48 | |
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49 | protected: |
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50 | struct NodeT |
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51 | { |
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52 | int first_in,first_out; |
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53 | NodeT() : first_in(-1), first_out(-1) {} |
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54 | }; |
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55 | struct EdgeT |
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56 | { |
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57 | int target, source, next_in, next_out; |
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58 | //FIXME: is this necessary? |
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59 | EdgeT() : next_in(-1), next_out(-1) {} |
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60 | }; |
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61 | |
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62 | std::vector<NodeT> nodes; |
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63 | |
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64 | std::vector<EdgeT> edges; |
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65 | |
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66 | |
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67 | public: |
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68 | |
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69 | typedef SmartGraphBase Graph; |
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70 | |
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71 | class Node; |
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72 | class Edge; |
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73 | |
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74 | |
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75 | public: |
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76 | |
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77 | SmartGraphBase() : nodes(), edges() { } |
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78 | SmartGraphBase(const SmartGraphBase &_g) : nodes(_g.nodes), edges(_g.edges) { } |
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79 | |
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80 | typedef True NodeNumTag; |
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81 | typedef True EdgeNumTag; |
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82 | |
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83 | ///Number of nodes. |
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84 | int nodeNum() const { return nodes.size(); } |
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85 | ///Number of edges. |
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86 | int edgeNum() const { return edges.size(); } |
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87 | |
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88 | /// Maximum node ID. |
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89 | |
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90 | /// Maximum node ID. |
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91 | ///\sa id(Node) |
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92 | int maxId(Node) const { return nodes.size()-1; } |
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93 | /// Maximum edge ID. |
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94 | |
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95 | /// Maximum edge ID. |
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96 | ///\sa id(Edge) |
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97 | int maxId(Edge) const { return edges.size()-1; } |
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98 | |
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99 | Node source(Edge e) const { return edges[e.n].source; } |
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100 | Node target(Edge e) const { return edges[e.n].target; } |
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101 | |
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102 | /// Node ID. |
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103 | |
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104 | /// The ID of a valid Node is a nonnegative integer not greater than |
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105 | /// \ref maxId(Node). The range of the ID's is not surely continuous |
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106 | /// and the greatest node ID can be actually less then \ref maxId(Node). |
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107 | /// |
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108 | /// The ID of the \ref INVALID node is -1. |
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109 | ///\return The ID of the node \c v. |
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110 | static int id(Node v) { return v.n; } |
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111 | /// Edge ID. |
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112 | |
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113 | /// The ID of a valid Edge is a nonnegative integer not greater than |
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114 | /// \ref maxId(Edge). The range of the ID's is not surely continuous |
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115 | /// and the greatest edge ID can be actually less then \ref maxId(Edge). |
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116 | /// |
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117 | /// The ID of the \ref INVALID edge is -1. |
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118 | ///\return The ID of the edge \c e. |
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119 | static int id(Edge e) { return e.n; } |
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120 | |
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121 | static Node fromId(int id, Node) { return Node(id);} |
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122 | |
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123 | static Edge fromId(int id, Edge) { return Edge(id);} |
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124 | |
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125 | Node addNode() { |
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126 | Node n; n.n=nodes.size(); |
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127 | nodes.push_back(NodeT()); //FIXME: Hmmm... |
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128 | return n; |
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129 | } |
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130 | |
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131 | Edge addEdge(Node u, Node v) { |
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132 | Edge e; e.n=edges.size(); edges.push_back(EdgeT()); //FIXME: Hmmm... |
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133 | edges[e.n].source=u.n; edges[e.n].target=v.n; |
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134 | edges[e.n].next_out=nodes[u.n].first_out; |
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135 | edges[e.n].next_in=nodes[v.n].first_in; |
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136 | nodes[u.n].first_out=nodes[v.n].first_in=e.n; |
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137 | |
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138 | return e; |
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139 | } |
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140 | |
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141 | void clear() { |
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142 | edges.clear(); |
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143 | nodes.clear(); |
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144 | } |
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145 | |
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146 | |
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147 | class Node { |
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148 | friend class SmartGraphBase; |
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149 | friend class SmartGraph; |
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150 | |
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151 | protected: |
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152 | int n; |
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153 | ///\e |
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154 | |
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155 | ///\todo It should be removed (or at least define a setToId() instead). |
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156 | /// |
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157 | Node(int nn) {n=nn;} |
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158 | public: |
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159 | Node() {} |
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160 | Node (Invalid) { n=-1; } |
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161 | bool operator==(const Node i) const {return n==i.n;} |
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162 | bool operator!=(const Node i) const {return n!=i.n;} |
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163 | bool operator<(const Node i) const {return n<i.n;} |
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164 | }; |
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165 | |
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166 | |
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167 | class Edge { |
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168 | friend class SmartGraphBase; |
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169 | friend class SmartGraph; |
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170 | |
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171 | protected: |
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172 | int n; |
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173 | ///\todo It should be removed (or at least define a setToId() instead). |
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174 | /// |
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175 | Edge(int nn) {n=nn;} |
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176 | public: |
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177 | Edge() { } |
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178 | Edge (Invalid) { n=-1; } |
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179 | bool operator==(const Edge i) const {return n==i.n;} |
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180 | bool operator!=(const Edge i) const {return n!=i.n;} |
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181 | bool operator<(const Edge i) const {return n<i.n;} |
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182 | }; |
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183 | |
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184 | void first(Node& node) const { |
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185 | node.n = nodes.size() - 1; |
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186 | } |
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187 | |
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188 | static void next(Node& node) { |
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189 | --node.n; |
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190 | } |
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191 | |
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192 | void first(Edge& edge) const { |
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193 | edge.n = edges.size() - 1; |
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194 | } |
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195 | |
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196 | static void next(Edge& edge) { |
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197 | --edge.n; |
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198 | } |
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199 | |
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200 | void firstOut(Edge& edge, const Node& node) const { |
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201 | edge.n = nodes[node.n].first_out; |
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202 | } |
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203 | |
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204 | void nextOut(Edge& edge) const { |
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205 | edge.n = edges[edge.n].next_out; |
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206 | } |
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207 | |
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208 | void firstIn(Edge& edge, const Node& node) const { |
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209 | edge.n = nodes[node.n].first_in; |
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210 | } |
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211 | |
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212 | void nextIn(Edge& edge) const { |
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213 | edge.n = edges[edge.n].next_in; |
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214 | } |
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215 | |
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216 | Edge _findEdge(Node u,Node v, Edge prev = INVALID) |
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217 | { |
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218 | int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out; |
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219 | while(e!=-1 && edges[e].target!=v.n) e = edges[e].next_out; |
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220 | prev.n=e; |
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221 | return prev; |
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222 | } |
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223 | |
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224 | Node _split(Node n, bool connect = true) |
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225 | { |
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226 | Node b = addNode(); |
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227 | nodes[b.n].first_out=nodes[n.n].first_out; |
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228 | nodes[n.n].first_out=-1; |
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229 | for(int i=nodes[b.n].first_out;i!=-1;i++) edges[i].source=b.n; |
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230 | if(connect) addEdge(n,b); |
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231 | return b; |
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232 | } |
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233 | |
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234 | }; |
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235 | |
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236 | typedef ClearableGraphExtender< |
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237 | ExtendableGraphExtender< |
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238 | MappableGraphExtender< |
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239 | IterableGraphExtender< |
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240 | AlterableGraphExtender<SmartGraphBase> > > > > ExtendedSmartGraphBase; |
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241 | |
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242 | /// \addtogroup graphs |
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243 | /// @{ |
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244 | |
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245 | ///A smart graph class. |
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246 | |
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247 | ///This is a simple and fast graph implementation. |
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248 | ///It is also quite memory efficient, but at the price |
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249 | ///that <b> it does support only limited (only stack-like) |
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250 | ///node and edge deletions</b>. |
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251 | ///It conforms to |
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252 | ///the \ref concept::ExtendableGraph "ExtendableGraph" concept. |
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253 | ///\sa concept::ExtendableGraph. |
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254 | /// |
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255 | ///\author Alpar Juttner |
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256 | class SmartGraph : public ExtendedSmartGraphBase { |
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257 | public: |
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258 | /// Finds an edge between two nodes. |
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259 | |
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260 | /// Finds an edge from node \c u to node \c v. |
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261 | /// |
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262 | /// If \c prev is \ref INVALID (this is the default value), then |
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263 | /// it finds the first edge from \c u to \c v. Otherwise it looks for |
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264 | /// the next edge from \c u to \c v after \c prev. |
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265 | /// \return The found edge or \ref INVALID if there is no such an edge. |
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266 | /// |
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267 | /// Thus you can iterate through each edge from \c u to \c v as it follows. |
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268 | /// \code |
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269 | /// for(Edge e=G.findEdge(u,v);e!=INVALID;e=G.findEdge(u,v,e)) { |
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270 | /// ... |
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271 | /// } |
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272 | /// \endcode |
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273 | /// \todo Possibly it should be a global function. |
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274 | Edge findEdge(Node u,Node v, Edge prev = INVALID) |
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275 | { |
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276 | return _findEdge(u,v,prev); |
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277 | } |
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278 | |
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279 | class SnapShot; |
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280 | friend class SnapShot; |
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281 | |
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282 | protected: |
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283 | void restoreSnapShot(const SnapShot &s) |
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284 | { |
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285 | while(s.edge_num<edges.size()) { |
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286 | Parent::getNotifier(Edge()).erase(Edge(edges.size()-1)); |
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287 | nodes[edges.back().target].first_in=edges.back().next_in; |
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288 | nodes[edges.back().source].first_out=edges.back().next_out; |
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289 | edges.pop_back(); |
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290 | } |
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291 | //nodes.resize(s.nodes_num); |
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292 | while(s.node_num<nodes.size()) { |
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293 | Parent::getNotifier(Node()).erase(Node(nodes.size()-1)); |
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294 | nodes.pop_back(); |
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295 | } |
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296 | } |
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297 | |
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298 | public: |
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299 | |
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300 | ///Split a node. |
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301 | |
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302 | ///This function splits a node. First a new node is added to the graph, |
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303 | ///then the source of each outgoing edge of \c n is moved to this new node. |
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304 | ///If \c connect is \c true (this is the default value), then a new edge |
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305 | ///from \c n to the newly created node is also added. |
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306 | ///\return The newly created node. |
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307 | /// |
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308 | ///\note The <tt>Edge</tt>s |
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309 | ///referencing a moved edge remain |
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310 | ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s |
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311 | ///may be invalidated. |
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312 | ///\warning This functionality cannot be used together with the SnapShot |
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313 | ///feature. |
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314 | ///\todo It could be implemented in a bit faster way. |
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315 | Node split(Node n, bool connect = true) |
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316 | { |
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317 | return _split(n,connect); |
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318 | } |
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319 | |
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320 | |
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321 | ///Class to make a snapshot of the graph and to restrore to it later. |
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322 | |
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323 | ///Class to make a snapshot of the graph and to restrore to it later. |
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324 | /// |
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325 | ///The newly added nodes and edges can be removed using the |
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326 | ///restore() function. |
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327 | ///\note After you restore a state, you cannot restore |
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328 | ///a later state, in other word you cannot add again the edges deleted |
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329 | ///by restore() using another SnapShot instance. |
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330 | /// |
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331 | class SnapShot |
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332 | { |
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333 | SmartGraph *g; |
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334 | protected: |
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335 | friend class SmartGraph; |
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336 | unsigned int node_num; |
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337 | unsigned int edge_num; |
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338 | public: |
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339 | ///Default constructor. |
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340 | |
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341 | ///Default constructor. |
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342 | ///To actually make a snapshot you must call save(). |
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343 | /// |
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344 | SnapShot() : g(0) {} |
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345 | ///Constructor that immediately makes a snapshot |
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346 | |
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347 | ///This constructor immediately makes a snapshot of the graph. |
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348 | ///\param _g The graph we make a snapshot of. |
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349 | SnapShot(SmartGraph &_g) :g(&_g) { |
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350 | node_num=g->nodes.size(); |
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351 | edge_num=g->edges.size(); |
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352 | } |
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353 | |
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354 | ///Make a snapshot. |
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355 | |
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356 | ///Make a snapshot of the graph. |
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357 | /// |
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358 | ///This function can be called more than once. In case of a repeated |
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359 | ///call, the previous snapshot gets lost. |
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360 | ///\param _g The graph we make the snapshot of. |
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361 | void save(SmartGraph &_g) |
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362 | { |
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363 | g=&_g; |
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364 | node_num=g->nodes.size(); |
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365 | edge_num=g->edges.size(); |
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366 | } |
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367 | |
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368 | ///Undo the changes until a snapshot. |
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369 | |
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370 | ///Undo the changes until a snapshot created by save(). |
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371 | /// |
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372 | ///\note After you restored a state, you cannot restore |
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373 | ///a later state, in other word you cannot add again the edges deleted |
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374 | ///by restore(). |
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375 | /// |
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376 | ///\todo This function might be called undo(). |
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377 | |
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378 | void restore() |
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379 | { |
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380 | g->restoreSnapShot(*this); |
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381 | } |
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382 | }; |
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383 | }; |
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384 | |
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385 | |
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386 | /**************** Undirected List Graph ****************/ |
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387 | |
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388 | typedef ClearableUndirGraphExtender< |
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389 | ExtendableUndirGraphExtender< |
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390 | MappableUndirGraphExtender< |
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391 | IterableUndirGraphExtender< |
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392 | AlterableUndirGraphExtender< |
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393 | UndirGraphExtender<SmartGraphBase> > > > > > ExtendedUndirSmartGraphBase; |
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394 | |
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395 | ///A smart undirected graph class. |
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396 | |
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397 | ///This is a simple and fast undirected graph implementation. |
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398 | ///It is also quite memory efficient, but at the price |
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399 | ///that <b> it does support only limited (only stack-like) |
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400 | ///node and edge deletions</b>. |
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401 | ///Except from this it conforms to |
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402 | ///the \ref concept::UndirGraph "UndirGraph" concept. |
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403 | ///\sa concept::UndirGraph. |
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404 | /// |
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405 | ///\todo SnapShot hasn't been implemented yet. |
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406 | /// |
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407 | class UndirSmartGraph : public ExtendedUndirSmartGraphBase { |
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408 | }; |
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409 | |
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410 | |
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411 | /// @} |
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412 | } //namespace lemon |
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413 | |
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414 | |
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415 | #endif //LEMON_SMART_GRAPH_H |
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