1 | /* -*- C++ -*- |
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2 | * lemon/topology.h - Part of LEMON, a generic C++ optimization library |
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3 | * |
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4 | * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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5 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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6 | * |
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7 | * Permission to use, modify and distribute this software is granted |
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8 | * provided that this copyright notice appears in all copies. For |
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9 | * precise terms see the accompanying LICENSE file. |
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10 | * |
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11 | * This software is provided "AS IS" with no warranty of any kind, |
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12 | * express or implied, and with no claim as to its suitability for any |
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13 | * purpose. |
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14 | * |
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15 | */ |
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16 | |
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17 | #ifndef LEMON_TOPOLOGY_H |
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18 | #define LEMON_TOPOLOGY_H |
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19 | |
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20 | #include <lemon/dfs.h> |
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21 | #include <lemon/graph_utils.h> |
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22 | |
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23 | #include <lemon/concept/graph.h> |
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24 | #include <lemon/concept/undir_graph.h> |
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25 | #include <lemon/concept_check.h> |
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26 | |
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27 | /// \ingroup flowalgs |
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28 | /// \file |
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29 | /// \brief Topology related algorithms |
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30 | /// |
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31 | /// Topology related algorithms |
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32 | |
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33 | namespace lemon { |
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34 | |
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35 | namespace _topology_bits { |
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36 | |
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37 | template <typename NodeMap> |
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38 | class BackCounterMap { |
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39 | public: |
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40 | BackCounterMap(NodeMap& _nodeMap, int _counter) |
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41 | : nodeMap(_nodeMap), counter(_counter) {} |
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42 | |
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43 | void set(typename NodeMap::Key key, bool val) { |
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44 | if (val) { |
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45 | nodeMap.set(key, --counter); |
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46 | } else { |
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47 | nodeMap.set(key, -1); |
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48 | } |
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49 | } |
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50 | |
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51 | bool operator[](typename NodeMap::Key key) const { |
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52 | return nodeMap[key] != -1; |
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53 | } |
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54 | |
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55 | private: |
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56 | NodeMap& nodeMap; |
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57 | int counter; |
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58 | }; |
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59 | } |
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60 | |
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61 | // \todo Its to special output // ReadWriteMap |
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62 | template <typename Graph, typename NodeMap> |
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63 | bool topological_sort(const Graph& graph, NodeMap& nodeMap) { |
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64 | using namespace _topology_bits; |
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65 | |
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66 | checkConcept<concept::StaticGraph, Graph>(); |
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67 | checkConcept<concept::ReadWriteMap<typename Graph::Node, int>, NodeMap>(); |
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68 | |
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69 | typedef typename Graph::Node Node; |
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70 | typedef typename Graph::NodeIt NodeIt; |
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71 | typedef typename Graph::Edge Edge; |
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72 | |
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73 | typedef BackCounterMap<NodeMap> ProcessedMap; |
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74 | |
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75 | typename Dfs<Graph>::template DefProcessedMap<ProcessedMap>:: |
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76 | Create dfs(graph); |
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77 | |
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78 | ProcessedMap processed(nodeMap, countNodes(graph)); |
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79 | |
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80 | dfs.processedMap(processed); |
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81 | dfs.init(); |
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82 | for (NodeIt it(graph); it != INVALID; ++it) { |
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83 | if (!dfs.reached(it)) { |
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84 | dfs.addSource(it); |
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85 | while (!dfs.emptyQueue()) { |
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86 | Edge edge = dfs.nextEdge(); |
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87 | Node target = graph.target(edge); |
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88 | if (dfs.reached(target) && !processed[target]) { |
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89 | return false; |
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90 | } |
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91 | dfs.processNextEdge(); |
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92 | } |
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93 | } |
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94 | } |
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95 | return true; |
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96 | } |
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97 | |
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98 | /// \brief Check that the given graph is a DAG. |
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99 | /// |
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100 | /// Check that the given graph is a DAG. The DAG is |
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101 | /// an Directed Acyclic Graph. |
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102 | template <typename Graph> |
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103 | bool dag(const Graph& graph) { |
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104 | |
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105 | checkConcept<concept::StaticGraph, Graph>(); |
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106 | |
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107 | typedef typename Graph::Node Node; |
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108 | typedef typename Graph::NodeIt NodeIt; |
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109 | typedef typename Graph::Edge Edge; |
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110 | |
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111 | typedef typename Graph::template NodeMap<bool> ProcessedMap; |
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112 | |
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113 | typename Dfs<Graph>::template DefProcessedMap<ProcessedMap>:: |
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114 | Create dfs(graph); |
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115 | |
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116 | ProcessedMap processed(graph); |
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117 | dfs.processedMap(processed); |
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118 | |
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119 | dfs.init(); |
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120 | for (NodeIt it(graph); it != INVALID; ++it) { |
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121 | if (!dfs.reached(it)) { |
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122 | dfs.addSource(it); |
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123 | while (!dfs.emptyQueue()) { |
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124 | Edge edge = dfs.nextEdge(); |
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125 | Node target = graph.target(edge); |
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126 | if (dfs.reached(target) && !processed[target]) { |
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127 | return false; |
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128 | } |
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129 | dfs.processNextEdge(); |
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130 | } |
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131 | } |
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132 | } |
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133 | return true; |
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134 | } |
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135 | |
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136 | // UndirGraph algorithms |
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137 | |
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138 | /// \brief Check that the given undirected graph is connected. |
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139 | /// |
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140 | /// Check that the given undirected graph connected. |
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141 | template <typename UndirGraph> |
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142 | bool connected(const UndirGraph& graph) { |
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143 | checkConcept<concept::UndirGraph, UndirGraph>(); |
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144 | typedef typename UndirGraph::NodeIt NodeIt; |
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145 | if (NodeIt(graph) == INVALID) return false; |
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146 | Dfs<UndirGraph> dfs(graph); |
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147 | dfs.run(NodeIt(graph)); |
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148 | for (NodeIt it(graph); it != INVALID; ++it) { |
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149 | if (!dfs.reached(it)) { |
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150 | return false; |
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151 | } |
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152 | } |
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153 | return true; |
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154 | } |
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155 | |
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156 | /// \brief Check that the given undirected graph is acyclic. |
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157 | /// |
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158 | /// Check that the given undirected graph acyclic. |
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159 | template <typename UndirGraph> |
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160 | bool acyclic(const UndirGraph& graph) { |
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161 | checkConcept<concept::UndirGraph, UndirGraph>(); |
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162 | typedef typename UndirGraph::Node Node; |
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163 | typedef typename UndirGraph::NodeIt NodeIt; |
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164 | typedef typename UndirGraph::Edge Edge; |
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165 | Dfs<UndirGraph> dfs(graph); |
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166 | dfs.init(); |
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167 | for (NodeIt it(graph); it != INVALID; ++it) { |
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168 | if (!dfs.reached(it)) { |
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169 | dfs.addSource(it); |
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170 | while (!dfs.emptyQueue()) { |
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171 | Edge edge = dfs.nextEdge(); |
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172 | Node source = graph.source(edge); |
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173 | Node target = graph.target(edge); |
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174 | if (dfs.reached(target) && |
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175 | dfs.pred(source) != graph.oppositeEdge(edge)) { |
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176 | return false; |
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177 | } |
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178 | dfs.processNextEdge(); |
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179 | } |
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180 | } |
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181 | } |
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182 | return true; |
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183 | } |
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184 | |
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185 | /// \brief Check that the given undirected graph is tree. |
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186 | /// |
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187 | /// Check that the given undirected graph is tree. |
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188 | template <typename UndirGraph> |
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189 | bool tree(const UndirGraph& graph) { |
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190 | checkConcept<concept::UndirGraph, UndirGraph>(); |
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191 | typedef typename UndirGraph::Node Node; |
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192 | typedef typename UndirGraph::NodeIt NodeIt; |
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193 | typedef typename UndirGraph::Edge Edge; |
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194 | if (NodeIt(graph) == INVALID) return false; |
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195 | Dfs<UndirGraph> dfs(graph); |
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196 | dfs.init(); |
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197 | dfs.addSource(NodeIt(graph)); |
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198 | while (!dfs.emptyQueue()) { |
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199 | Edge edge = dfs.nextEdge(); |
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200 | Node source = graph.source(edge); |
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201 | Node target = graph.target(edge); |
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202 | if (dfs.reached(target) && |
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203 | dfs.pred(source) != graph.oppositeEdge(edge)) { |
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204 | return false; |
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205 | } |
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206 | dfs.processNextEdge(); |
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207 | } |
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208 | for (NodeIt it(graph); it != INVALID; ++it) { |
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209 | if (!dfs.reached(it)) { |
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210 | return false; |
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211 | } |
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212 | } |
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213 | return true; |
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214 | } |
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215 | |
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216 | |
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217 | } //namespace lemon |
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218 | |
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219 | #endif //LEMON_TOPOLOGY_H |
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