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) 2003-2008 |
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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_SMART_GRAPH_H |
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20 | #define LEMON_SMART_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 SmartDigraph and SmartGraph classes. |
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25 | |
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26 | #include <vector> |
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27 | |
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28 | #include <lemon/bits/invalid.h> |
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29 | |
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30 | #include <lemon/bits/base_extender.h> |
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31 | #include <lemon/bits/graph_extender.h> |
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32 | |
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33 | #include <lemon/bits/utility.h> |
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34 | #include <lemon/error.h> |
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35 | |
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36 | #include <lemon/bits/graph_extender.h> |
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37 | |
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38 | namespace lemon { |
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39 | |
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40 | class SmartDigraph; |
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41 | ///Base of SmartDigraph |
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42 | |
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43 | ///Base of SmartDigraph |
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44 | /// |
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45 | class SmartDigraphBase { |
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46 | protected: |
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47 | |
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48 | struct NodeT |
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49 | { |
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50 | int first_in, first_out; |
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51 | NodeT() {} |
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52 | }; |
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53 | struct ArcT |
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54 | { |
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55 | int target, source, next_in, next_out; |
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56 | ArcT() {} |
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57 | }; |
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58 | |
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59 | std::vector<NodeT> nodes; |
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60 | std::vector<ArcT> arcs; |
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61 | |
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62 | public: |
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63 | |
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64 | typedef SmartDigraphBase Graph; |
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65 | |
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66 | class Node; |
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67 | class Arc; |
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68 | |
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69 | public: |
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70 | |
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71 | SmartDigraphBase() : nodes(), arcs() { } |
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72 | SmartDigraphBase(const SmartDigraphBase &_g) |
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73 | : nodes(_g.nodes), arcs(_g.arcs) { } |
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74 | |
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75 | typedef True NodeNumTag; |
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76 | typedef True ArcNumTag; |
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77 | |
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78 | int nodeNum() const { return nodes.size(); } |
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79 | int arcNum() const { return arcs.size(); } |
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80 | |
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81 | int maxNodeId() const { return nodes.size()-1; } |
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82 | int maxArcId() const { return arcs.size()-1; } |
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83 | |
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84 | Node addNode() { |
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85 | int n = nodes.size(); |
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86 | nodes.push_back(NodeT()); |
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87 | nodes[n].first_in = -1; |
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88 | nodes[n].first_out = -1; |
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89 | return Node(n); |
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90 | } |
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91 | |
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92 | Arc addArc(Node u, Node v) { |
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93 | int n = arcs.size(); |
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94 | arcs.push_back(ArcT()); |
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95 | arcs[n].source = u._id; |
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96 | arcs[n].target = v._id; |
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97 | arcs[n].next_out = nodes[u._id].first_out; |
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98 | arcs[n].next_in = nodes[v._id].first_in; |
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99 | nodes[u._id].first_out = nodes[v._id].first_in = n; |
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100 | |
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101 | return Arc(n); |
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102 | } |
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103 | |
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104 | void clear() { |
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105 | arcs.clear(); |
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106 | nodes.clear(); |
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107 | } |
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108 | |
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109 | Node source(Arc a) const { return Node(arcs[a._id].source); } |
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110 | Node target(Arc a) const { return Node(arcs[a._id].target); } |
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111 | |
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112 | static int id(Node v) { return v._id; } |
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113 | static int id(Arc a) { return a._id; } |
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114 | |
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115 | static Node nodeFromId(int id) { return Node(id);} |
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116 | static Arc arcFromId(int id) { return Arc(id);} |
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117 | |
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118 | class Node { |
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119 | friend class SmartDigraphBase; |
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120 | friend class SmartDigraph; |
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121 | |
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122 | protected: |
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123 | int _id; |
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124 | explicit Node(int id) : _id(id) {} |
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125 | public: |
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126 | Node() {} |
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127 | Node (Invalid) : _id(-1) {} |
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128 | bool operator==(const Node i) const {return _id == i._id;} |
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129 | bool operator!=(const Node i) const {return _id != i._id;} |
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130 | bool operator<(const Node i) const {return _id < i._id;} |
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131 | }; |
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132 | |
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133 | |
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134 | class Arc { |
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135 | friend class SmartDigraphBase; |
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136 | friend class SmartDigraph; |
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137 | |
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138 | protected: |
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139 | int _id; |
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140 | explicit Arc(int id) : _id(id) {} |
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141 | public: |
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142 | Arc() { } |
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143 | Arc (Invalid) : _id(-1) {} |
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144 | bool operator==(const Arc i) const {return _id == i._id;} |
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145 | bool operator!=(const Arc i) const {return _id != i._id;} |
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146 | bool operator<(const Arc i) const {return _id < i._id;} |
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147 | }; |
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148 | |
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149 | void first(Node& node) const { |
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150 | node._id = nodes.size() - 1; |
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151 | } |
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152 | |
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153 | static void next(Node& node) { |
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154 | --node._id; |
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155 | } |
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156 | |
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157 | void first(Arc& arc) const { |
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158 | arc._id = arcs.size() - 1; |
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159 | } |
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160 | |
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161 | static void next(Arc& arc) { |
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162 | --arc._id; |
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163 | } |
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164 | |
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165 | void firstOut(Arc& arc, const Node& node) const { |
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166 | arc._id = nodes[node._id].first_out; |
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167 | } |
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168 | |
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169 | void nextOut(Arc& arc) const { |
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170 | arc._id = arcs[arc._id].next_out; |
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171 | } |
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172 | |
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173 | void firstIn(Arc& arc, const Node& node) const { |
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174 | arc._id = nodes[node._id].first_in; |
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175 | } |
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176 | |
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177 | void nextIn(Arc& arc) const { |
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178 | arc._id = arcs[arc._id].next_in; |
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179 | } |
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180 | |
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181 | }; |
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182 | |
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183 | typedef DigraphExtender<SmartDigraphBase> ExtendedSmartDigraphBase; |
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184 | |
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185 | ///\ingroup graphs |
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186 | /// |
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187 | ///\brief A smart directed graph class. |
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188 | /// |
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189 | ///This is a simple and fast digraph implementation. |
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190 | ///It is also quite memory efficient, but at the price |
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191 | ///that <b> it does support only limited (only stack-like) |
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192 | ///node and arc deletions</b>. |
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193 | ///It conforms to the \ref concepts::Digraph "Digraph concept" with |
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194 | ///an important extra feature that its maps are real \ref |
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195 | ///concepts::ReferenceMap "reference map"s. |
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196 | /// |
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197 | ///\sa concepts::Digraph. |
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198 | /// |
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199 | ///\author Alpar Juttner |
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200 | class SmartDigraph : public ExtendedSmartDigraphBase { |
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201 | public: |
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202 | |
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203 | typedef ExtendedSmartDigraphBase Parent; |
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204 | |
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205 | private: |
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206 | |
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207 | ///SmartDigraph is \e not copy constructible. Use DigraphCopy() instead. |
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208 | |
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209 | ///SmartDigraph is \e not copy constructible. Use DigraphCopy() instead. |
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210 | /// |
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211 | SmartDigraph(const SmartDigraph &) : ExtendedSmartDigraphBase() {}; |
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212 | ///\brief Assignment of SmartDigraph to another one is \e not allowed. |
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213 | ///Use DigraphCopy() instead. |
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214 | |
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215 | ///Assignment of SmartDigraph to another one is \e not allowed. |
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216 | ///Use DigraphCopy() instead. |
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217 | void operator=(const SmartDigraph &) {} |
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218 | |
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219 | public: |
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220 | |
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221 | /// Constructor |
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222 | |
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223 | /// Constructor. |
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224 | /// |
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225 | SmartDigraph() {}; |
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226 | |
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227 | ///Add a new node to the digraph. |
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228 | |
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229 | /// \return the new node. |
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230 | /// |
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231 | Node addNode() { return Parent::addNode(); } |
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232 | |
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233 | ///Add a new arc to the digraph. |
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234 | |
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235 | ///Add a new arc to the digraph with source node \c s |
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236 | ///and target node \c t. |
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237 | ///\return the new arc. |
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238 | Arc addArc(const Node& s, const Node& t) { |
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239 | return Parent::addArc(s, t); |
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240 | } |
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241 | |
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242 | /// \brief Using this it is possible to avoid the superfluous memory |
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243 | /// allocation. |
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244 | |
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245 | /// Using this it is possible to avoid the superfluous memory |
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246 | /// allocation: if you know that the digraph you want to build will |
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247 | /// be very large (e.g. it will contain millions of nodes and/or arcs) |
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248 | /// then it is worth reserving space for this amount before starting |
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249 | /// to build the digraph. |
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250 | /// \sa reserveArc |
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251 | void reserveNode(int n) { nodes.reserve(n); }; |
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252 | |
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253 | /// \brief Using this it is possible to avoid the superfluous memory |
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254 | /// allocation. |
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255 | |
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256 | /// Using this it is possible to avoid the superfluous memory |
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257 | /// allocation: if you know that the digraph you want to build will |
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258 | /// be very large (e.g. it will contain millions of nodes and/or arcs) |
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259 | /// then it is worth reserving space for this amount before starting |
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260 | /// to build the digraph. |
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261 | /// \sa reserveNode |
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262 | void reserveArc(int m) { arcs.reserve(m); }; |
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263 | |
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264 | ///Clear the digraph. |
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265 | |
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266 | ///Erase all the nodes and arcs from the digraph. |
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267 | /// |
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268 | void clear() { |
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269 | Parent::clear(); |
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270 | } |
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271 | |
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272 | ///Split a node. |
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273 | |
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274 | ///This function splits a node. First a new node is added to the digraph, |
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275 | ///then the source of each outgoing arc of \c n is moved to this new node. |
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276 | ///If \c connect is \c true (this is the default value), then a new arc |
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277 | ///from \c n to the newly created node is also added. |
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278 | ///\return The newly created node. |
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279 | /// |
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280 | ///\note The <tt>Arc</tt>s |
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281 | ///referencing a moved arc remain |
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282 | ///valid. However <tt>InArc</tt>'s and <tt>OutArc</tt>'s |
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283 | ///may be invalidated. |
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284 | ///\warning This functionality cannot be used together with the Snapshot |
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285 | ///feature. |
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286 | ///\todo It could be implemented in a bit faster way. |
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287 | Node split(Node n, bool connect = true) |
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288 | { |
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289 | Node b = addNode(); |
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290 | nodes[b._id].first_out=nodes[n._id].first_out; |
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291 | nodes[n._id].first_out=-1; |
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292 | for(int i=nodes[b._id].first_out;i!=-1;i++) arcs[i].source=b._id; |
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293 | if(connect) addArc(n,b); |
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294 | return b; |
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295 | } |
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296 | |
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297 | public: |
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298 | |
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299 | class Snapshot; |
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300 | |
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301 | protected: |
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302 | |
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303 | void restoreSnapshot(const Snapshot &s) |
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304 | { |
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305 | while(s.arc_num<arcs.size()) { |
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306 | Arc arc = arcFromId(arcs.size()-1); |
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307 | Parent::notifier(Arc()).erase(arc); |
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308 | nodes[arcs.back().source].first_out=arcs.back().next_out; |
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309 | nodes[arcs.back().target].first_in=arcs.back().next_in; |
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310 | arcs.pop_back(); |
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311 | } |
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312 | while(s.node_num<nodes.size()) { |
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313 | Node node = nodeFromId(nodes.size()-1); |
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314 | Parent::notifier(Node()).erase(node); |
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315 | nodes.pop_back(); |
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316 | } |
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317 | } |
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318 | |
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319 | public: |
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320 | |
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321 | ///Class to make a snapshot of the digraph and to restrore to it later. |
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322 | |
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323 | ///Class to make a snapshot of the digraph and to restrore to it later. |
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324 | /// |
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325 | ///The newly added nodes and arcs 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 arcs deleted |
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329 | ///by restore() using another one Snapshot instance. |
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330 | /// |
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331 | ///\warning If you do not use correctly the snapshot that can cause |
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332 | ///either broken program, invalid state of the digraph, valid but |
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333 | ///not the restored digraph or no change. Because the runtime performance |
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334 | ///the validity of the snapshot is not stored. |
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335 | class Snapshot |
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336 | { |
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337 | SmartDigraph *_graph; |
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338 | protected: |
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339 | friend class SmartDigraph; |
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340 | unsigned int node_num; |
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341 | unsigned int arc_num; |
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342 | public: |
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343 | ///Default constructor. |
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344 | |
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345 | ///Default constructor. |
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346 | ///To actually make a snapshot you must call save(). |
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347 | /// |
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348 | Snapshot() : _graph(0) {} |
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349 | ///Constructor that immediately makes a snapshot |
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350 | |
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351 | ///This constructor immediately makes a snapshot of the digraph. |
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352 | ///\param _g The digraph we make a snapshot of. |
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353 | Snapshot(SmartDigraph &graph) : _graph(&graph) { |
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354 | node_num=_graph->nodes.size(); |
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355 | arc_num=_graph->arcs.size(); |
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356 | } |
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357 | |
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358 | ///Make a snapshot. |
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359 | |
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360 | ///Make a snapshot of the digraph. |
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361 | /// |
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362 | ///This function can be called more than once. In case of a repeated |
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363 | ///call, the previous snapshot gets lost. |
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364 | ///\param _g The digraph we make the snapshot of. |
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365 | void save(SmartDigraph &graph) |
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366 | { |
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367 | _graph=&graph; |
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368 | node_num=_graph->nodes.size(); |
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369 | arc_num=_graph->arcs.size(); |
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370 | } |
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371 | |
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372 | ///Undo the changes until a snapshot. |
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373 | |
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374 | ///Undo the changes until a snapshot created by save(). |
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375 | /// |
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376 | ///\note After you restored a state, you cannot restore |
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377 | ///a later state, in other word you cannot add again the arcs deleted |
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378 | ///by restore(). |
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379 | void restore() |
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380 | { |
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381 | _graph->restoreSnapshot(*this); |
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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 | |
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387 | class SmartGraphBase { |
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388 | |
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389 | protected: |
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390 | |
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391 | struct NodeT { |
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392 | int first_out; |
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393 | }; |
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394 | |
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395 | struct ArcT { |
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396 | int target; |
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397 | int next_out; |
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398 | }; |
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399 | |
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400 | std::vector<NodeT> nodes; |
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401 | std::vector<ArcT> arcs; |
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402 | |
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403 | int first_free_arc; |
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404 | |
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405 | public: |
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406 | |
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407 | typedef SmartGraphBase Digraph; |
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408 | |
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409 | class Node; |
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410 | class Arc; |
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411 | class Edge; |
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412 | |
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413 | class Node { |
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414 | friend class SmartGraphBase; |
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415 | protected: |
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416 | |
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417 | int _id; |
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418 | explicit Node(int id) { _id = id;} |
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419 | |
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420 | public: |
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421 | Node() {} |
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422 | Node (Invalid) { _id = -1; } |
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423 | bool operator==(const Node& node) const {return _id == node._id;} |
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424 | bool operator!=(const Node& node) const {return _id != node._id;} |
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425 | bool operator<(const Node& node) const {return _id < node._id;} |
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426 | }; |
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427 | |
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428 | class Edge { |
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429 | friend class SmartGraphBase; |
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430 | protected: |
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431 | |
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432 | int _id; |
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433 | explicit Edge(int id) { _id = id;} |
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434 | |
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435 | public: |
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436 | Edge() {} |
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437 | Edge (Invalid) { _id = -1; } |
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438 | bool operator==(const Edge& arc) const {return _id == arc._id;} |
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439 | bool operator!=(const Edge& arc) const {return _id != arc._id;} |
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440 | bool operator<(const Edge& arc) const {return _id < arc._id;} |
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441 | }; |
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442 | |
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443 | class Arc { |
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444 | friend class SmartGraphBase; |
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445 | protected: |
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446 | |
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447 | int _id; |
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448 | explicit Arc(int id) { _id = id;} |
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449 | |
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450 | public: |
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451 | operator Edge() const { return edgeFromId(_id / 2); } |
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452 | |
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453 | Arc() {} |
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454 | Arc (Invalid) { _id = -1; } |
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455 | bool operator==(const Arc& arc) const {return _id == arc._id;} |
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456 | bool operator!=(const Arc& arc) const {return _id != arc._id;} |
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457 | bool operator<(const Arc& arc) const {return _id < arc._id;} |
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458 | }; |
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459 | |
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460 | |
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461 | |
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462 | SmartGraphBase() |
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463 | : nodes(), arcs() {} |
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464 | |
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465 | |
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466 | int maxNodeId() const { return nodes.size()-1; } |
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467 | int maxEdgeId() const { return arcs.size() / 2 - 1; } |
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468 | int maxArcId() const { return arcs.size()-1; } |
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469 | |
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470 | Node source(Arc e) const { return Node(arcs[e._id ^ 1].target); } |
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471 | Node target(Arc e) const { return Node(arcs[e._id].target); } |
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472 | |
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473 | Node source(Edge e) const { return Node(arcs[2 * e._id].target); } |
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474 | Node target(Edge e) const { return Node(arcs[2 * e._id + 1].target); } |
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475 | |
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476 | static bool direction(Arc e) { |
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477 | return (e._id & 1) == 1; |
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478 | } |
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479 | |
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480 | static Arc direct(Edge e, bool d) { |
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481 | return Arc(e._id * 2 + (d ? 1 : 0)); |
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482 | } |
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483 | |
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484 | void first(Node& node) const { |
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485 | node._id = nodes.size() - 1; |
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486 | } |
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487 | |
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488 | void next(Node& node) const { |
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489 | --node._id; |
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490 | } |
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491 | |
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492 | void first(Arc& arc) const { |
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493 | arc._id = arcs.size() - 1; |
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494 | } |
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495 | |
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496 | void next(Arc& arc) const { |
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497 | --arc._id; |
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498 | } |
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499 | |
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500 | void first(Edge& arc) const { |
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501 | arc._id = arcs.size() / 2 - 1; |
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502 | } |
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503 | |
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504 | void next(Edge& arc) const { |
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505 | --arc._id; |
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506 | } |
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507 | |
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508 | void firstOut(Arc &arc, const Node& v) const { |
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509 | arc._id = nodes[v._id].first_out; |
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510 | } |
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511 | void nextOut(Arc &arc) const { |
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512 | arc._id = arcs[arc._id].next_out; |
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513 | } |
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514 | |
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515 | void firstIn(Arc &arc, const Node& v) const { |
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516 | arc._id = ((nodes[v._id].first_out) ^ 1); |
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517 | if (arc._id == -2) arc._id = -1; |
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518 | } |
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519 | void nextIn(Arc &arc) const { |
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520 | arc._id = ((arcs[arc._id ^ 1].next_out) ^ 1); |
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521 | if (arc._id == -2) arc._id = -1; |
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522 | } |
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523 | |
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524 | void firstInc(Edge &arc, bool& d, const Node& v) const { |
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525 | int de = nodes[v._id].first_out; |
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526 | if (de != -1) { |
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527 | arc._id = de / 2; |
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528 | d = ((de & 1) == 1); |
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529 | } else { |
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530 | arc._id = -1; |
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531 | d = true; |
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532 | } |
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533 | } |
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534 | void nextInc(Edge &arc, bool& d) const { |
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535 | int de = (arcs[(arc._id * 2) | (d ? 1 : 0)].next_out); |
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536 | if (de != -1) { |
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537 | arc._id = de / 2; |
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538 | d = ((de & 1) == 1); |
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539 | } else { |
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540 | arc._id = -1; |
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541 | d = true; |
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542 | } |
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543 | } |
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544 | |
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545 | static int id(Node v) { return v._id; } |
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546 | static int id(Arc e) { return e._id; } |
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547 | static int id(Edge e) { return e._id; } |
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548 | |
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549 | static Node nodeFromId(int id) { return Node(id);} |
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550 | static Arc arcFromId(int id) { return Arc(id);} |
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551 | static Edge edgeFromId(int id) { return Edge(id);} |
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552 | |
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553 | Node addNode() { |
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554 | int n = nodes.size(); |
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555 | nodes.push_back(NodeT()); |
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556 | nodes[n].first_out = -1; |
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557 | |
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558 | return Node(n); |
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559 | } |
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560 | |
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561 | Edge addArc(Node u, Node v) { |
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562 | int n = arcs.size(); |
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563 | arcs.push_back(ArcT()); |
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564 | arcs.push_back(ArcT()); |
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565 | |
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566 | arcs[n].target = u._id; |
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567 | arcs[n | 1].target = v._id; |
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568 | |
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569 | arcs[n].next_out = nodes[v._id].first_out; |
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570 | nodes[v._id].first_out = n; |
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571 | |
---|
572 | arcs[n | 1].next_out = nodes[u._id].first_out; |
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573 | nodes[u._id].first_out = (n | 1); |
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574 | |
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575 | return Edge(n / 2); |
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576 | } |
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577 | |
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578 | void clear() { |
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579 | arcs.clear(); |
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580 | nodes.clear(); |
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581 | } |
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582 | |
---|
583 | }; |
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584 | |
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585 | typedef GraphExtender<SmartGraphBase> ExtendedSmartGraphBase; |
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586 | |
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587 | /// \ingroup graphs |
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588 | /// |
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589 | /// \brief A smart undirected graph class. |
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590 | /// |
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591 | /// This is a simple and fast graph implementation. |
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592 | /// It is also quite memory efficient, but at the price |
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593 | /// that <b> it does support only limited (only stack-like) |
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594 | /// node and arc deletions</b>. |
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595 | /// Except from this it conforms to |
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596 | /// the \ref concepts::Graph "Graph concept". |
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597 | /// |
---|
598 | /// It also has an |
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599 | /// important extra feature that |
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600 | /// its maps are real \ref concepts::ReferenceMap "reference map"s. |
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601 | /// |
---|
602 | /// \sa concepts::Graph. |
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603 | /// |
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604 | class SmartGraph : public ExtendedSmartGraphBase { |
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605 | private: |
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606 | |
---|
607 | ///SmartGraph is \e not copy constructible. Use GraphCopy() instead. |
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608 | |
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609 | ///SmartGraph is \e not copy constructible. Use GraphCopy() instead. |
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610 | /// |
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611 | SmartGraph(const SmartGraph &) : ExtendedSmartGraphBase() {}; |
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612 | |
---|
613 | ///\brief Assignment of SmartGraph to another one is \e not allowed. |
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614 | ///Use GraphCopy() instead. |
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615 | |
---|
616 | ///Assignment of SmartGraph to another one is \e not allowed. |
---|
617 | ///Use GraphCopy() instead. |
---|
618 | void operator=(const SmartGraph &) {} |
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619 | |
---|
620 | public: |
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621 | |
---|
622 | typedef ExtendedSmartGraphBase Parent; |
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623 | |
---|
624 | /// Constructor |
---|
625 | |
---|
626 | /// Constructor. |
---|
627 | /// |
---|
628 | SmartGraph() {} |
---|
629 | |
---|
630 | ///Add a new node to the graph. |
---|
631 | |
---|
632 | /// \return the new node. |
---|
633 | /// |
---|
634 | Node addNode() { return Parent::addNode(); } |
---|
635 | |
---|
636 | ///Add a new edge to the graph. |
---|
637 | |
---|
638 | ///Add a new edge to the graph with node \c s |
---|
639 | ///and \c t. |
---|
640 | ///\return the new edge. |
---|
641 | Edge addEdge(const Node& s, const Node& t) { |
---|
642 | return Parent::addArc(s, t); |
---|
643 | } |
---|
644 | |
---|
645 | ///Clear the graph. |
---|
646 | |
---|
647 | ///Erase all the nodes and edges from the graph. |
---|
648 | /// |
---|
649 | void clear() { |
---|
650 | Parent::clear(); |
---|
651 | } |
---|
652 | |
---|
653 | public: |
---|
654 | |
---|
655 | class Snapshot; |
---|
656 | |
---|
657 | protected: |
---|
658 | |
---|
659 | void saveSnapshot(Snapshot &s) |
---|
660 | { |
---|
661 | s._graph = this; |
---|
662 | s.node_num = nodes.size(); |
---|
663 | s.arc_num = arcs.size(); |
---|
664 | } |
---|
665 | |
---|
666 | void restoreSnapshot(const Snapshot &s) |
---|
667 | { |
---|
668 | while(s.arc_num<arcs.size()) { |
---|
669 | int n=arcs.size()-1; |
---|
670 | Edge arc=edgeFromId(n/2); |
---|
671 | Parent::notifier(Edge()).erase(arc); |
---|
672 | std::vector<Arc> dir; |
---|
673 | dir.push_back(arcFromId(n)); |
---|
674 | dir.push_back(arcFromId(n-1)); |
---|
675 | Parent::notifier(Arc()).erase(dir); |
---|
676 | nodes[arcs[n].target].first_out=arcs[n].next_out; |
---|
677 | nodes[arcs[n-1].target].first_out=arcs[n-1].next_out; |
---|
678 | arcs.pop_back(); |
---|
679 | arcs.pop_back(); |
---|
680 | } |
---|
681 | while(s.node_num<nodes.size()) { |
---|
682 | int n=nodes.size()-1; |
---|
683 | Node node = nodeFromId(n); |
---|
684 | Parent::notifier(Node()).erase(node); |
---|
685 | nodes.pop_back(); |
---|
686 | } |
---|
687 | } |
---|
688 | |
---|
689 | public: |
---|
690 | |
---|
691 | ///Class to make a snapshot of the digraph and to restrore to it later. |
---|
692 | |
---|
693 | ///Class to make a snapshot of the digraph and to restrore to it later. |
---|
694 | /// |
---|
695 | ///The newly added nodes and arcs can be removed using the |
---|
696 | ///restore() function. |
---|
697 | /// |
---|
698 | ///\note After you restore a state, you cannot restore |
---|
699 | ///a later state, in other word you cannot add again the arcs deleted |
---|
700 | ///by restore() using another one Snapshot instance. |
---|
701 | /// |
---|
702 | ///\warning If you do not use correctly the snapshot that can cause |
---|
703 | ///either broken program, invalid state of the digraph, valid but |
---|
704 | ///not the restored digraph or no change. Because the runtime performance |
---|
705 | ///the validity of the snapshot is not stored. |
---|
706 | class Snapshot |
---|
707 | { |
---|
708 | SmartGraph *_graph; |
---|
709 | protected: |
---|
710 | friend class SmartGraph; |
---|
711 | unsigned int node_num; |
---|
712 | unsigned int arc_num; |
---|
713 | public: |
---|
714 | ///Default constructor. |
---|
715 | |
---|
716 | ///Default constructor. |
---|
717 | ///To actually make a snapshot you must call save(). |
---|
718 | /// |
---|
719 | Snapshot() : _graph(0) {} |
---|
720 | ///Constructor that immediately makes a snapshot |
---|
721 | |
---|
722 | ///This constructor immediately makes a snapshot of the digraph. |
---|
723 | ///\param g The digraph we make a snapshot of. |
---|
724 | Snapshot(SmartGraph &graph) { |
---|
725 | graph.saveSnapshot(*this); |
---|
726 | } |
---|
727 | |
---|
728 | ///Make a snapshot. |
---|
729 | |
---|
730 | ///Make a snapshot of the graph. |
---|
731 | /// |
---|
732 | ///This function can be called more than once. In case of a repeated |
---|
733 | ///call, the previous snapshot gets lost. |
---|
734 | ///\param g The digraph we make the snapshot of. |
---|
735 | void save(SmartGraph &graph) |
---|
736 | { |
---|
737 | graph.saveSnapshot(*this); |
---|
738 | } |
---|
739 | |
---|
740 | ///Undo the changes until a snapshot. |
---|
741 | |
---|
742 | ///Undo the changes until a snapshot created by save(). |
---|
743 | /// |
---|
744 | ///\note After you restored a state, you cannot restore |
---|
745 | ///a later state, in other word you cannot add again the arcs deleted |
---|
746 | ///by restore(). |
---|
747 | void restore() |
---|
748 | { |
---|
749 | _graph->restoreSnapshot(*this); |
---|
750 | } |
---|
751 | }; |
---|
752 | }; |
---|
753 | |
---|
754 | } //namespace lemon |
---|
755 | |
---|
756 | |
---|
757 | #endif //LEMON_SMART_GRAPH_H |
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