1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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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) 2003-2009 |
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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/core.h> |
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29 | #include <lemon/error.h> |
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30 | #include <lemon/bits/graph_extender.h> |
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31 | |
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32 | namespace lemon { |
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33 | |
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34 | class SmartDigraph; |
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35 | |
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36 | class SmartDigraphBase { |
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37 | protected: |
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38 | |
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39 | struct NodeT |
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40 | { |
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41 | int first_in, first_out; |
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42 | NodeT() {} |
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43 | }; |
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44 | struct ArcT |
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45 | { |
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46 | int target, source, next_in, next_out; |
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47 | ArcT() {} |
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48 | }; |
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49 | |
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50 | std::vector<NodeT> nodes; |
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51 | std::vector<ArcT> arcs; |
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52 | |
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53 | public: |
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54 | |
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55 | typedef SmartDigraphBase Digraph; |
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56 | |
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57 | class Node; |
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58 | class Arc; |
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59 | |
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60 | public: |
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61 | |
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62 | SmartDigraphBase() : nodes(), arcs() { } |
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63 | SmartDigraphBase(const SmartDigraphBase &_g) |
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64 | : nodes(_g.nodes), arcs(_g.arcs) { } |
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65 | |
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66 | typedef True NodeNumTag; |
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67 | typedef True ArcNumTag; |
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68 | |
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69 | int nodeNum() const { return nodes.size(); } |
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70 | int arcNum() const { return arcs.size(); } |
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71 | |
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72 | int maxNodeId() const { return nodes.size()-1; } |
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73 | int maxArcId() const { return arcs.size()-1; } |
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74 | |
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75 | Node addNode() { |
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76 | int n = nodes.size(); |
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77 | nodes.push_back(NodeT()); |
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78 | nodes[n].first_in = -1; |
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79 | nodes[n].first_out = -1; |
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80 | return Node(n); |
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81 | } |
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82 | |
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83 | Arc addArc(Node u, Node v) { |
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84 | int n = arcs.size(); |
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85 | arcs.push_back(ArcT()); |
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86 | arcs[n].source = u._id; |
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87 | arcs[n].target = v._id; |
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88 | arcs[n].next_out = nodes[u._id].first_out; |
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89 | arcs[n].next_in = nodes[v._id].first_in; |
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90 | nodes[u._id].first_out = nodes[v._id].first_in = n; |
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91 | |
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92 | return Arc(n); |
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93 | } |
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94 | |
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95 | void clear() { |
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96 | arcs.clear(); |
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97 | nodes.clear(); |
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98 | } |
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99 | |
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100 | Node source(Arc a) const { return Node(arcs[a._id].source); } |
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101 | Node target(Arc a) const { return Node(arcs[a._id].target); } |
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102 | |
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103 | static int id(Node v) { return v._id; } |
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104 | static int id(Arc a) { return a._id; } |
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105 | |
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106 | static Node nodeFromId(int id) { return Node(id);} |
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107 | static Arc arcFromId(int id) { return Arc(id);} |
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108 | |
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109 | bool valid(Node n) const { |
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110 | return n._id >= 0 && n._id < static_cast<int>(nodes.size()); |
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111 | } |
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112 | bool valid(Arc a) const { |
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113 | return a._id >= 0 && a._id < static_cast<int>(arcs.size()); |
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114 | } |
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115 | |
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116 | class Node { |
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117 | friend class SmartDigraphBase; |
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118 | friend class SmartDigraph; |
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119 | |
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120 | protected: |
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121 | int _id; |
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122 | explicit Node(int id) : _id(id) {} |
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123 | public: |
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124 | Node() {} |
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125 | Node (Invalid) : _id(-1) {} |
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126 | bool operator==(const Node i) const {return _id == i._id;} |
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127 | bool operator!=(const Node i) const {return _id != i._id;} |
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128 | bool operator<(const Node i) const {return _id < i._id;} |
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129 | }; |
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130 | |
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131 | |
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132 | class Arc { |
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133 | friend class SmartDigraphBase; |
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134 | friend class SmartDigraph; |
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135 | |
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136 | protected: |
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137 | int _id; |
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138 | explicit Arc(int id) : _id(id) {} |
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139 | public: |
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140 | Arc() { } |
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141 | Arc (Invalid) : _id(-1) {} |
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142 | bool operator==(const Arc i) const {return _id == i._id;} |
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143 | bool operator!=(const Arc i) const {return _id != i._id;} |
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144 | bool operator<(const Arc i) const {return _id < i._id;} |
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145 | }; |
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146 | |
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147 | void first(Node& node) const { |
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148 | node._id = nodes.size() - 1; |
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149 | } |
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150 | |
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151 | static void next(Node& node) { |
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152 | --node._id; |
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153 | } |
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154 | |
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155 | void first(Arc& arc) const { |
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156 | arc._id = arcs.size() - 1; |
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157 | } |
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158 | |
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159 | static void next(Arc& arc) { |
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160 | --arc._id; |
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161 | } |
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162 | |
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163 | void firstOut(Arc& arc, const Node& node) const { |
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164 | arc._id = nodes[node._id].first_out; |
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165 | } |
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166 | |
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167 | void nextOut(Arc& arc) const { |
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168 | arc._id = arcs[arc._id].next_out; |
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169 | } |
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170 | |
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171 | void firstIn(Arc& arc, const Node& node) const { |
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172 | arc._id = nodes[node._id].first_in; |
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173 | } |
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174 | |
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175 | void nextIn(Arc& arc) const { |
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176 | arc._id = arcs[arc._id].next_in; |
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177 | } |
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178 | |
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179 | }; |
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180 | |
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181 | typedef DigraphExtender<SmartDigraphBase> ExtendedSmartDigraphBase; |
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182 | |
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183 | ///\ingroup graphs |
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184 | /// |
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185 | ///\brief A smart directed graph class. |
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186 | /// |
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187 | ///\ref SmartDigraph is a simple and fast digraph implementation. |
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188 | ///It is also quite memory efficient but at the price |
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189 | ///that it does not support node and arc deletion |
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190 | ///(except for the Snapshot feature). |
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191 | /// |
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192 | ///This type fully conforms to the \ref concepts::Digraph "Digraph concept" |
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193 | ///and it also provides some additional functionalities. |
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194 | ///Most of its member functions and nested classes are documented |
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195 | ///only in the concept class. |
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196 | /// |
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197 | ///This class provides constant time counting for nodes and arcs. |
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198 | /// |
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199 | ///\sa concepts::Digraph |
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200 | ///\sa SmartGraph |
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201 | class SmartDigraph : public ExtendedSmartDigraphBase { |
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202 | typedef ExtendedSmartDigraphBase Parent; |
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203 | |
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204 | private: |
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205 | /// Digraphs are \e not copy constructible. Use DigraphCopy instead. |
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206 | SmartDigraph(const SmartDigraph &) : ExtendedSmartDigraphBase() {}; |
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207 | /// \brief Assignment of a digraph to another one is \e not allowed. |
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208 | /// Use DigraphCopy instead. |
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209 | void operator=(const SmartDigraph &) {} |
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210 | |
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211 | public: |
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212 | |
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213 | /// Constructor |
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214 | |
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215 | /// Constructor. |
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216 | /// |
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217 | SmartDigraph() {}; |
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218 | |
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219 | ///Add a new node to the digraph. |
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220 | |
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221 | ///This function adds a new node to the digraph. |
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222 | ///\return The new node. |
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223 | Node addNode() { return Parent::addNode(); } |
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224 | |
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225 | ///Add a new arc to the digraph. |
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226 | |
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227 | ///This function adds a new arc to the digraph with source node \c s |
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228 | ///and target node \c t. |
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229 | ///\return The new arc. |
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230 | Arc addArc(Node s, Node t) { |
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231 | return Parent::addArc(s, t); |
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232 | } |
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233 | |
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234 | /// \brief Node validity check |
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235 | /// |
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236 | /// This function gives back \c true if the given node is valid, |
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237 | /// i.e. it is a real node of the digraph. |
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238 | /// |
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239 | /// \warning A removed node (using Snapshot) could become valid again |
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240 | /// if new nodes are added to the digraph. |
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241 | bool valid(Node n) const { return Parent::valid(n); } |
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242 | |
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243 | /// \brief Arc validity check |
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244 | /// |
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245 | /// This function gives back \c true if the given arc is valid, |
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246 | /// i.e. it is a real arc of the digraph. |
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247 | /// |
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248 | /// \warning A removed arc (using Snapshot) could become valid again |
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249 | /// if new arcs are added to the graph. |
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250 | bool valid(Arc a) const { return Parent::valid(a); } |
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251 | |
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252 | ///Split a node. |
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253 | |
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254 | ///This function splits the given node. First, a new node is added |
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255 | ///to the digraph, then the source of each outgoing arc of node \c n |
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256 | ///is moved to this new node. |
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257 | ///If the second parameter \c connect is \c true (this is the default |
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258 | ///value), then a new arc from node \c n to the newly created node |
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259 | ///is also added. |
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260 | ///\return The newly created node. |
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261 | /// |
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262 | ///\note All iterators remain valid. |
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263 | /// |
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264 | ///\warning This functionality cannot be used together with the Snapshot |
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265 | ///feature. |
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266 | Node split(Node n, bool connect = true) |
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267 | { |
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268 | Node b = addNode(); |
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269 | nodes[b._id].first_out=nodes[n._id].first_out; |
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270 | nodes[n._id].first_out=-1; |
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271 | for(int i=nodes[b._id].first_out; i!=-1; i=arcs[i].next_out) { |
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272 | arcs[i].source=b._id; |
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273 | } |
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274 | if(connect) addArc(n,b); |
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275 | return b; |
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276 | } |
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277 | |
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278 | ///Clear the digraph. |
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279 | |
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280 | ///This function erases all nodes and arcs from the digraph. |
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281 | /// |
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282 | void clear() { |
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283 | Parent::clear(); |
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284 | } |
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285 | |
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286 | /// Reserve memory for nodes. |
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287 | |
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288 | /// Using this function, it is possible to avoid superfluous memory |
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289 | /// allocation: if you know that the digraph you want to build will |
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290 | /// be large (e.g. it will contain millions of nodes and/or arcs), |
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291 | /// then it is worth reserving space for this amount before starting |
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292 | /// to build the digraph. |
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293 | /// \sa reserveArc() |
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294 | void reserveNode(int n) { nodes.reserve(n); }; |
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295 | |
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296 | /// Reserve memory for arcs. |
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297 | |
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298 | /// Using this function, it is possible to avoid superfluous memory |
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299 | /// allocation: if you know that the digraph you want to build will |
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300 | /// be large (e.g. it will contain millions of nodes and/or arcs), |
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301 | /// then it is worth reserving space for this amount before starting |
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302 | /// to build the digraph. |
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303 | /// \sa reserveNode() |
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304 | void reserveArc(int m) { arcs.reserve(m); }; |
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305 | |
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306 | public: |
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307 | |
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308 | class Snapshot; |
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309 | |
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310 | protected: |
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311 | |
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312 | void restoreSnapshot(const Snapshot &s) |
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313 | { |
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314 | while(s.arc_num<arcs.size()) { |
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315 | Arc arc = arcFromId(arcs.size()-1); |
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316 | Parent::notifier(Arc()).erase(arc); |
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317 | nodes[arcs.back().source].first_out=arcs.back().next_out; |
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318 | nodes[arcs.back().target].first_in=arcs.back().next_in; |
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319 | arcs.pop_back(); |
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320 | } |
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321 | while(s.node_num<nodes.size()) { |
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322 | Node node = nodeFromId(nodes.size()-1); |
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323 | Parent::notifier(Node()).erase(node); |
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324 | nodes.pop_back(); |
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325 | } |
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326 | } |
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327 | |
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328 | public: |
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329 | |
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330 | ///Class to make a snapshot of the digraph and to restore it later. |
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331 | |
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332 | ///Class to make a snapshot of the digraph and to restore it later. |
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333 | /// |
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334 | ///The newly added nodes and arcs can be removed using the |
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335 | ///restore() function. This is the only way for deleting nodes and/or |
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336 | ///arcs from a SmartDigraph structure. |
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337 | /// |
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338 | ///\note After a state is restored, you cannot restore a later state, |
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339 | ///i.e. you cannot add the removed nodes and arcs again using |
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340 | ///another Snapshot instance. |
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341 | /// |
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342 | ///\warning Node splitting cannot be restored. |
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343 | ///\warning The validity of the snapshot is not stored due to |
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344 | ///performance reasons. If you do not use the snapshot correctly, |
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345 | ///it can cause broken program, invalid or not restored state of |
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346 | ///the digraph or no change. |
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347 | class Snapshot |
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348 | { |
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349 | SmartDigraph *_graph; |
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350 | protected: |
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351 | friend class SmartDigraph; |
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352 | unsigned int node_num; |
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353 | unsigned int arc_num; |
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354 | public: |
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355 | ///Default constructor. |
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356 | |
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357 | ///Default constructor. |
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358 | ///You have to call save() to actually make a snapshot. |
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359 | Snapshot() : _graph(0) {} |
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360 | ///Constructor that immediately makes a snapshot |
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361 | |
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362 | ///This constructor immediately makes a snapshot of the given digraph. |
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363 | /// |
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364 | Snapshot(SmartDigraph &gr) : _graph(&gr) { |
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365 | node_num=_graph->nodes.size(); |
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366 | arc_num=_graph->arcs.size(); |
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367 | } |
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368 | |
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369 | ///Make a snapshot. |
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370 | |
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371 | ///This function makes a snapshot of the given digraph. |
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372 | ///It can be called more than once. In case of a repeated |
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373 | ///call, the previous snapshot gets lost. |
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374 | void save(SmartDigraph &gr) { |
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375 | _graph=&gr; |
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376 | node_num=_graph->nodes.size(); |
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377 | arc_num=_graph->arcs.size(); |
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378 | } |
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379 | |
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380 | ///Undo the changes until a snapshot. |
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381 | |
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382 | ///This function undos the changes until the last snapshot |
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383 | ///created by save() or Snapshot(SmartDigraph&). |
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384 | void restore() |
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385 | { |
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386 | _graph->restoreSnapshot(*this); |
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387 | } |
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388 | }; |
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389 | }; |
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390 | |
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391 | |
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392 | class SmartGraphBase { |
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393 | |
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394 | protected: |
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395 | |
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396 | struct NodeT { |
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397 | int first_out; |
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398 | }; |
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399 | |
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400 | struct ArcT { |
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401 | int target; |
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402 | int next_out; |
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403 | }; |
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404 | |
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405 | std::vector<NodeT> nodes; |
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406 | std::vector<ArcT> arcs; |
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407 | |
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408 | int first_free_arc; |
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409 | |
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410 | public: |
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411 | |
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412 | typedef SmartGraphBase Graph; |
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413 | |
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414 | class Node; |
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415 | class Arc; |
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416 | class Edge; |
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417 | |
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418 | class Node { |
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419 | friend class SmartGraphBase; |
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420 | protected: |
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421 | |
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422 | int _id; |
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423 | explicit Node(int id) { _id = id;} |
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424 | |
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425 | public: |
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426 | Node() {} |
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427 | Node (Invalid) { _id = -1; } |
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428 | bool operator==(const Node& node) const {return _id == node._id;} |
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429 | bool operator!=(const Node& node) const {return _id != node._id;} |
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430 | bool operator<(const Node& node) const {return _id < node._id;} |
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431 | }; |
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432 | |
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433 | class Edge { |
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434 | friend class SmartGraphBase; |
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435 | protected: |
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436 | |
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437 | int _id; |
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438 | explicit Edge(int id) { _id = id;} |
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439 | |
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440 | public: |
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441 | Edge() {} |
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442 | Edge (Invalid) { _id = -1; } |
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443 | bool operator==(const Edge& arc) const {return _id == arc._id;} |
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444 | bool operator!=(const Edge& arc) const {return _id != arc._id;} |
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445 | bool operator<(const Edge& arc) const {return _id < arc._id;} |
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446 | }; |
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447 | |
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448 | class Arc { |
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449 | friend class SmartGraphBase; |
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450 | protected: |
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451 | |
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452 | int _id; |
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453 | explicit Arc(int id) { _id = id;} |
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454 | |
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455 | public: |
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456 | operator Edge() const { |
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457 | return _id != -1 ? edgeFromId(_id / 2) : INVALID; |
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458 | } |
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459 | |
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460 | Arc() {} |
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461 | Arc (Invalid) { _id = -1; } |
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462 | bool operator==(const Arc& arc) const {return _id == arc._id;} |
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463 | bool operator!=(const Arc& arc) const {return _id != arc._id;} |
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464 | bool operator<(const Arc& arc) const {return _id < arc._id;} |
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465 | }; |
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466 | |
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467 | |
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468 | |
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469 | SmartGraphBase() |
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470 | : nodes(), arcs() {} |
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471 | |
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472 | typedef True NodeNumTag; |
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473 | typedef True EdgeNumTag; |
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474 | typedef True ArcNumTag; |
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475 | |
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476 | int nodeNum() const { return nodes.size(); } |
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477 | int edgeNum() const { return arcs.size() / 2; } |
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478 | int arcNum() const { return arcs.size(); } |
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479 | |
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480 | int maxNodeId() const { return nodes.size()-1; } |
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481 | int maxEdgeId() const { return arcs.size() / 2 - 1; } |
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482 | int maxArcId() const { return arcs.size()-1; } |
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483 | |
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484 | Node source(Arc e) const { return Node(arcs[e._id ^ 1].target); } |
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485 | Node target(Arc e) const { return Node(arcs[e._id].target); } |
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486 | |
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487 | Node u(Edge e) const { return Node(arcs[2 * e._id].target); } |
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488 | Node v(Edge e) const { return Node(arcs[2 * e._id + 1].target); } |
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489 | |
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490 | static bool direction(Arc e) { |
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491 | return (e._id & 1) == 1; |
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492 | } |
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493 | |
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494 | static Arc direct(Edge e, bool d) { |
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495 | return Arc(e._id * 2 + (d ? 1 : 0)); |
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496 | } |
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497 | |
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498 | void first(Node& node) const { |
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499 | node._id = nodes.size() - 1; |
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500 | } |
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501 | |
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502 | static void next(Node& node) { |
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503 | --node._id; |
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504 | } |
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505 | |
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506 | void first(Arc& arc) const { |
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507 | arc._id = arcs.size() - 1; |
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508 | } |
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509 | |
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510 | static void next(Arc& arc) { |
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511 | --arc._id; |
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512 | } |
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513 | |
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514 | void first(Edge& arc) const { |
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515 | arc._id = arcs.size() / 2 - 1; |
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516 | } |
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517 | |
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518 | static void next(Edge& arc) { |
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519 | --arc._id; |
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520 | } |
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521 | |
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522 | void firstOut(Arc &arc, const Node& v) const { |
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523 | arc._id = nodes[v._id].first_out; |
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524 | } |
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525 | void nextOut(Arc &arc) const { |
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526 | arc._id = arcs[arc._id].next_out; |
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527 | } |
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528 | |
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529 | void firstIn(Arc &arc, const Node& v) const { |
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530 | arc._id = ((nodes[v._id].first_out) ^ 1); |
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531 | if (arc._id == -2) arc._id = -1; |
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532 | } |
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533 | void nextIn(Arc &arc) const { |
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534 | arc._id = ((arcs[arc._id ^ 1].next_out) ^ 1); |
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535 | if (arc._id == -2) arc._id = -1; |
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536 | } |
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537 | |
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538 | void firstInc(Edge &arc, bool& d, const Node& v) const { |
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539 | int de = nodes[v._id].first_out; |
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540 | if (de != -1) { |
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541 | arc._id = de / 2; |
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542 | d = ((de & 1) == 1); |
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543 | } else { |
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544 | arc._id = -1; |
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545 | d = true; |
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546 | } |
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547 | } |
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548 | void nextInc(Edge &arc, bool& d) const { |
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549 | int de = (arcs[(arc._id * 2) | (d ? 1 : 0)].next_out); |
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550 | if (de != -1) { |
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551 | arc._id = de / 2; |
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552 | d = ((de & 1) == 1); |
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553 | } else { |
---|
554 | arc._id = -1; |
---|
555 | d = true; |
---|
556 | } |
---|
557 | } |
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558 | |
---|
559 | static int id(Node v) { return v._id; } |
---|
560 | static int id(Arc e) { return e._id; } |
---|
561 | static int id(Edge e) { return e._id; } |
---|
562 | |
---|
563 | static Node nodeFromId(int id) { return Node(id);} |
---|
564 | static Arc arcFromId(int id) { return Arc(id);} |
---|
565 | static Edge edgeFromId(int id) { return Edge(id);} |
---|
566 | |
---|
567 | bool valid(Node n) const { |
---|
568 | return n._id >= 0 && n._id < static_cast<int>(nodes.size()); |
---|
569 | } |
---|
570 | bool valid(Arc a) const { |
---|
571 | return a._id >= 0 && a._id < static_cast<int>(arcs.size()); |
---|
572 | } |
---|
573 | bool valid(Edge e) const { |
---|
574 | return e._id >= 0 && 2 * e._id < static_cast<int>(arcs.size()); |
---|
575 | } |
---|
576 | |
---|
577 | Node addNode() { |
---|
578 | int n = nodes.size(); |
---|
579 | nodes.push_back(NodeT()); |
---|
580 | nodes[n].first_out = -1; |
---|
581 | |
---|
582 | return Node(n); |
---|
583 | } |
---|
584 | |
---|
585 | Edge addEdge(Node u, Node v) { |
---|
586 | int n = arcs.size(); |
---|
587 | arcs.push_back(ArcT()); |
---|
588 | arcs.push_back(ArcT()); |
---|
589 | |
---|
590 | arcs[n].target = u._id; |
---|
591 | arcs[n | 1].target = v._id; |
---|
592 | |
---|
593 | arcs[n].next_out = nodes[v._id].first_out; |
---|
594 | nodes[v._id].first_out = n; |
---|
595 | |
---|
596 | arcs[n | 1].next_out = nodes[u._id].first_out; |
---|
597 | nodes[u._id].first_out = (n | 1); |
---|
598 | |
---|
599 | return Edge(n / 2); |
---|
600 | } |
---|
601 | |
---|
602 | void clear() { |
---|
603 | arcs.clear(); |
---|
604 | nodes.clear(); |
---|
605 | } |
---|
606 | |
---|
607 | }; |
---|
608 | |
---|
609 | typedef GraphExtender<SmartGraphBase> ExtendedSmartGraphBase; |
---|
610 | |
---|
611 | /// \ingroup graphs |
---|
612 | /// |
---|
613 | /// \brief A smart undirected graph class. |
---|
614 | /// |
---|
615 | /// \ref SmartGraph is a simple and fast graph implementation. |
---|
616 | /// It is also quite memory efficient but at the price |
---|
617 | /// that it does not support node and edge deletion |
---|
618 | /// (except for the Snapshot feature). |
---|
619 | /// |
---|
620 | /// This type fully conforms to the \ref concepts::Graph "Graph concept" |
---|
621 | /// and it also provides some additional functionalities. |
---|
622 | /// Most of its member functions and nested classes are documented |
---|
623 | /// only in the concept class. |
---|
624 | /// |
---|
625 | /// This class provides constant time counting for nodes, edges and arcs. |
---|
626 | /// |
---|
627 | /// \sa concepts::Graph |
---|
628 | /// \sa SmartDigraph |
---|
629 | class SmartGraph : public ExtendedSmartGraphBase { |
---|
630 | typedef ExtendedSmartGraphBase Parent; |
---|
631 | |
---|
632 | private: |
---|
633 | /// Graphs are \e not copy constructible. Use GraphCopy instead. |
---|
634 | SmartGraph(const SmartGraph &) : ExtendedSmartGraphBase() {}; |
---|
635 | /// \brief Assignment of a graph to another one is \e not allowed. |
---|
636 | /// Use GraphCopy instead. |
---|
637 | void operator=(const SmartGraph &) {} |
---|
638 | |
---|
639 | public: |
---|
640 | |
---|
641 | /// Constructor |
---|
642 | |
---|
643 | /// Constructor. |
---|
644 | /// |
---|
645 | SmartGraph() {} |
---|
646 | |
---|
647 | /// \brief Add a new node to the graph. |
---|
648 | /// |
---|
649 | /// This function adds a new node to the graph. |
---|
650 | /// \return The new node. |
---|
651 | Node addNode() { return Parent::addNode(); } |
---|
652 | |
---|
653 | /// \brief Add a new edge to the graph. |
---|
654 | /// |
---|
655 | /// This function adds a new edge to the graph between nodes |
---|
656 | /// \c u and \c v with inherent orientation from node \c u to |
---|
657 | /// node \c v. |
---|
658 | /// \return The new edge. |
---|
659 | Edge addEdge(Node u, Node v) { |
---|
660 | return Parent::addEdge(u, v); |
---|
661 | } |
---|
662 | |
---|
663 | /// \brief Node validity check |
---|
664 | /// |
---|
665 | /// This function gives back \c true if the given node is valid, |
---|
666 | /// i.e. it is a real node of the graph. |
---|
667 | /// |
---|
668 | /// \warning A removed node (using Snapshot) could become valid again |
---|
669 | /// if new nodes are added to the graph. |
---|
670 | bool valid(Node n) const { return Parent::valid(n); } |
---|
671 | |
---|
672 | /// \brief Edge validity check |
---|
673 | /// |
---|
674 | /// This function gives back \c true if the given edge is valid, |
---|
675 | /// i.e. it is a real edge of the graph. |
---|
676 | /// |
---|
677 | /// \warning A removed edge (using Snapshot) could become valid again |
---|
678 | /// if new edges are added to the graph. |
---|
679 | bool valid(Edge e) const { return Parent::valid(e); } |
---|
680 | |
---|
681 | /// \brief Arc validity check |
---|
682 | /// |
---|
683 | /// This function gives back \c true if the given arc is valid, |
---|
684 | /// i.e. it is a real arc of the graph. |
---|
685 | /// |
---|
686 | /// \warning A removed arc (using Snapshot) could become valid again |
---|
687 | /// if new edges are added to the graph. |
---|
688 | bool valid(Arc a) const { return Parent::valid(a); } |
---|
689 | |
---|
690 | ///Clear the graph. |
---|
691 | |
---|
692 | ///This function erases all nodes and arcs from the graph. |
---|
693 | /// |
---|
694 | void clear() { |
---|
695 | Parent::clear(); |
---|
696 | } |
---|
697 | |
---|
698 | /// Reserve memory for nodes. |
---|
699 | |
---|
700 | /// Using this function, it is possible to avoid superfluous memory |
---|
701 | /// allocation: if you know that the graph you want to build will |
---|
702 | /// be large (e.g. it will contain millions of nodes and/or edges), |
---|
703 | /// then it is worth reserving space for this amount before starting |
---|
704 | /// to build the graph. |
---|
705 | /// \sa reserveEdge() |
---|
706 | void reserveNode(int n) { nodes.reserve(n); }; |
---|
707 | |
---|
708 | /// Reserve memory for edges. |
---|
709 | |
---|
710 | /// Using this function, it is possible to avoid superfluous memory |
---|
711 | /// allocation: if you know that the graph you want to build will |
---|
712 | /// be large (e.g. it will contain millions of nodes and/or edges), |
---|
713 | /// then it is worth reserving space for this amount before starting |
---|
714 | /// to build the graph. |
---|
715 | /// \sa reserveNode() |
---|
716 | void reserveEdge(int m) { arcs.reserve(2 * m); }; |
---|
717 | |
---|
718 | public: |
---|
719 | |
---|
720 | class Snapshot; |
---|
721 | |
---|
722 | protected: |
---|
723 | |
---|
724 | void saveSnapshot(Snapshot &s) |
---|
725 | { |
---|
726 | s._graph = this; |
---|
727 | s.node_num = nodes.size(); |
---|
728 | s.arc_num = arcs.size(); |
---|
729 | } |
---|
730 | |
---|
731 | void restoreSnapshot(const Snapshot &s) |
---|
732 | { |
---|
733 | while(s.arc_num<arcs.size()) { |
---|
734 | int n=arcs.size()-1; |
---|
735 | Edge arc=edgeFromId(n/2); |
---|
736 | Parent::notifier(Edge()).erase(arc); |
---|
737 | std::vector<Arc> dir; |
---|
738 | dir.push_back(arcFromId(n)); |
---|
739 | dir.push_back(arcFromId(n-1)); |
---|
740 | Parent::notifier(Arc()).erase(dir); |
---|
741 | nodes[arcs[n-1].target].first_out=arcs[n].next_out; |
---|
742 | nodes[arcs[n].target].first_out=arcs[n-1].next_out; |
---|
743 | arcs.pop_back(); |
---|
744 | arcs.pop_back(); |
---|
745 | } |
---|
746 | while(s.node_num<nodes.size()) { |
---|
747 | int n=nodes.size()-1; |
---|
748 | Node node = nodeFromId(n); |
---|
749 | Parent::notifier(Node()).erase(node); |
---|
750 | nodes.pop_back(); |
---|
751 | } |
---|
752 | } |
---|
753 | |
---|
754 | public: |
---|
755 | |
---|
756 | ///Class to make a snapshot of the graph and to restore it later. |
---|
757 | |
---|
758 | ///Class to make a snapshot of the graph and to restore it later. |
---|
759 | /// |
---|
760 | ///The newly added nodes and edges can be removed using the |
---|
761 | ///restore() function. This is the only way for deleting nodes and/or |
---|
762 | ///edges from a SmartGraph structure. |
---|
763 | /// |
---|
764 | ///\note After a state is restored, you cannot restore a later state, |
---|
765 | ///i.e. you cannot add the removed nodes and edges again using |
---|
766 | ///another Snapshot instance. |
---|
767 | /// |
---|
768 | ///\warning The validity of the snapshot is not stored due to |
---|
769 | ///performance reasons. If you do not use the snapshot correctly, |
---|
770 | ///it can cause broken program, invalid or not restored state of |
---|
771 | ///the graph or no change. |
---|
772 | class Snapshot |
---|
773 | { |
---|
774 | SmartGraph *_graph; |
---|
775 | protected: |
---|
776 | friend class SmartGraph; |
---|
777 | unsigned int node_num; |
---|
778 | unsigned int arc_num; |
---|
779 | public: |
---|
780 | ///Default constructor. |
---|
781 | |
---|
782 | ///Default constructor. |
---|
783 | ///You have to call save() to actually make a snapshot. |
---|
784 | Snapshot() : _graph(0) {} |
---|
785 | ///Constructor that immediately makes a snapshot |
---|
786 | |
---|
787 | /// This constructor immediately makes a snapshot of the given graph. |
---|
788 | /// |
---|
789 | Snapshot(SmartGraph &gr) { |
---|
790 | gr.saveSnapshot(*this); |
---|
791 | } |
---|
792 | |
---|
793 | ///Make a snapshot. |
---|
794 | |
---|
795 | ///This function makes a snapshot of the given graph. |
---|
796 | ///It can be called more than once. In case of a repeated |
---|
797 | ///call, the previous snapshot gets lost. |
---|
798 | void save(SmartGraph &gr) |
---|
799 | { |
---|
800 | gr.saveSnapshot(*this); |
---|
801 | } |
---|
802 | |
---|
803 | ///Undo the changes until the last snapshot. |
---|
804 | |
---|
805 | ///This function undos the changes until the last snapshot |
---|
806 | ///created by save() or Snapshot(SmartGraph&). |
---|
807 | void restore() |
---|
808 | { |
---|
809 | _graph->restoreSnapshot(*this); |
---|
810 | } |
---|
811 | }; |
---|
812 | }; |
---|
813 | |
---|
814 | } //namespace lemon |
---|
815 | |
---|
816 | |
---|
817 | #endif //LEMON_SMART_GRAPH_H |
---|