1 /* -*- C++ -*- |
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2 * src/lemon/bfs.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_BFS_H |
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18 #define LEMON_BFS_H |
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19 |
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20 ///\ingroup flowalgs |
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21 ///\file |
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22 ///\brief Bfs algorithm. |
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23 |
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24 #include <lemon/list_graph.h> |
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25 #include <lemon/graph_utils.h> |
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26 #include <lemon/invalid.h> |
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27 #include <lemon/error.h> |
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28 #include <lemon/maps.h> |
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29 |
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30 namespace lemon { |
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31 |
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32 |
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33 |
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34 ///Default traits class of Bfs class. |
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35 |
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36 ///Default traits class of Bfs class. |
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37 ///\param GR Graph type. |
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38 template<class GR> |
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39 struct BfsDefaultTraits |
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40 { |
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41 ///The graph type the algorithm runs on. |
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42 typedef GR Graph; |
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43 ///\brief The type of the map that stores the last |
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44 ///edges of the shortest paths. |
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45 /// |
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46 ///The type of the map that stores the last |
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47 ///edges of the shortest paths. |
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48 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
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49 /// |
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50 typedef typename Graph::template NodeMap<typename GR::Edge> PredMap; |
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51 ///Instantiates a PredMap. |
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52 |
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53 ///This function instantiates a \ref PredMap. |
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54 ///\param G is the graph, to which we would like to define the PredMap. |
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55 ///\todo The graph alone may be insufficient to initialize |
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56 static PredMap *createPredMap(const GR &G) |
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57 { |
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58 return new PredMap(G); |
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59 } |
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60 // ///\brief The type of the map that stores the last but one |
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61 // ///nodes of the shortest paths. |
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62 // /// |
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63 // ///The type of the map that stores the last but one |
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64 // ///nodes of the shortest paths. |
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65 // ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
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66 // /// |
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67 // typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap; |
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68 // ///Instantiates a PredNodeMap. |
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69 |
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70 // ///This function instantiates a \ref PredNodeMap. |
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71 // ///\param G is the graph, to which |
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72 // ///we would like to define the \ref PredNodeMap |
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73 // static PredNodeMap *createPredNodeMap(const GR &G) |
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74 // { |
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75 // return new PredNodeMap(); |
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76 // } |
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77 |
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78 ///The type of the map that indicates which nodes are processed. |
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79 |
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80 ///The type of the map that indicates which nodes are processed. |
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81 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
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82 ///\todo named parameter to set this type, function to read and write. |
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83 typedef NullMap<typename Graph::Node,bool> ProcessedMap; |
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84 ///Instantiates a ProcessedMap. |
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85 |
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86 ///This function instantiates a \ref ProcessedMap. |
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87 ///\param G is the graph, to which |
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88 ///we would like to define the \ref ProcessedMap |
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89 static ProcessedMap *createProcessedMap(const GR &) |
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90 { |
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91 return new ProcessedMap(); |
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92 } |
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93 ///The type of the map that indicates which nodes are reached. |
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94 |
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95 ///The type of the map that indicates which nodes are reached. |
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96 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
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97 ///\todo named parameter to set this type, function to read and write. |
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98 typedef typename Graph::template NodeMap<bool> ReachedMap; |
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99 ///Instantiates a ReachedMap. |
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100 |
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101 ///This function instantiates a \ref ReachedMap. |
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102 ///\param G is the graph, to which |
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103 ///we would like to define the \ref ReachedMap. |
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104 static ReachedMap *createReachedMap(const GR &G) |
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105 { |
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106 return new ReachedMap(G); |
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107 } |
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108 ///The type of the map that stores the dists of the nodes. |
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109 |
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110 ///The type of the map that stores the dists of the nodes. |
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111 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
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112 /// |
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113 typedef typename Graph::template NodeMap<int> DistMap; |
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114 ///Instantiates a DistMap. |
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115 |
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116 ///This function instantiates a \ref DistMap. |
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117 ///\param G is the graph, to which we would like to define the \ref DistMap |
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118 static DistMap *createDistMap(const GR &G) |
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119 { |
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120 return new DistMap(G); |
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121 } |
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122 }; |
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123 |
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124 ///%BFS algorithm class. |
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125 |
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126 ///\ingroup flowalgs |
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127 ///This class provides an efficient implementation of the %BFS algorithm. |
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128 /// |
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129 ///\param GR The graph type the algorithm runs on. The default value is |
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130 ///\ref ListGraph. The value of GR is not used directly by Bfs, it |
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131 ///is only passed to \ref BfsDefaultTraits. |
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132 ///\param TR Traits class to set various data types used by the algorithm. |
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133 ///The default traits class is |
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134 ///\ref BfsDefaultTraits "BfsDefaultTraits<GR>". |
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135 ///See \ref BfsDefaultTraits for the documentation of |
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136 ///a Bfs traits class. |
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137 /// |
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138 ///\author Alpar Juttner |
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139 ///\todo A compare object would be nice. |
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140 |
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141 #ifdef DOXYGEN |
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142 template <typename GR, |
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143 typename TR> |
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144 #else |
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145 template <typename GR=ListGraph, |
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146 typename TR=BfsDefaultTraits<GR> > |
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147 #endif |
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148 class Bfs { |
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149 public: |
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150 /** |
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151 * \brief \ref Exception for uninitialized parameters. |
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152 * |
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153 * This error represents problems in the initialization |
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154 * of the parameters of the algorithms. |
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155 */ |
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156 class UninitializedParameter : public lemon::UninitializedParameter { |
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157 public: |
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158 virtual const char* exceptionName() const { |
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159 return "lemon::Bfs::UninitializedParameter"; |
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160 } |
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161 }; |
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162 |
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163 typedef TR Traits; |
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164 ///The type of the underlying graph. |
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165 typedef typename TR::Graph Graph; |
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166 ///\e |
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167 typedef typename Graph::Node Node; |
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168 ///\e |
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169 typedef typename Graph::NodeIt NodeIt; |
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170 ///\e |
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171 typedef typename Graph::Edge Edge; |
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172 ///\e |
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173 typedef typename Graph::OutEdgeIt OutEdgeIt; |
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174 |
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175 ///\brief The type of the map that stores the last |
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176 ///edges of the shortest paths. |
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177 typedef typename TR::PredMap PredMap; |
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178 // ///\brief The type of the map that stores the last but one |
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179 // ///nodes of the shortest paths. |
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180 // typedef typename TR::PredNodeMap PredNodeMap; |
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181 ///The type of the map indicating which nodes are reached. |
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182 typedef typename TR::ReachedMap ReachedMap; |
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183 ///The type of the map indicating which nodes are processed. |
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184 typedef typename TR::ProcessedMap ProcessedMap; |
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185 ///The type of the map that stores the dists of the nodes. |
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186 typedef typename TR::DistMap DistMap; |
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187 private: |
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188 /// Pointer to the underlying graph. |
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189 const Graph *G; |
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190 ///Pointer to the map of predecessors edges. |
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191 PredMap *_pred; |
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192 ///Indicates if \ref _pred is locally allocated (\c true) or not. |
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193 bool local_pred; |
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194 // ///Pointer to the map of predecessors nodes. |
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195 // PredNodeMap *_predNode; |
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196 // ///Indicates if \ref _predNode is locally allocated (\c true) or not. |
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197 // bool local_predNode; |
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198 ///Pointer to the map of distances. |
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199 DistMap *_dist; |
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200 ///Indicates if \ref _dist is locally allocated (\c true) or not. |
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201 bool local_dist; |
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202 ///Pointer to the map of reached status of the nodes. |
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203 ReachedMap *_reached; |
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204 ///Indicates if \ref _reached is locally allocated (\c true) or not. |
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205 bool local_reached; |
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206 ///Pointer to the map of processed status of the nodes. |
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207 ProcessedMap *_processed; |
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208 ///Indicates if \ref _processed is locally allocated (\c true) or not. |
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209 bool local_processed; |
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210 |
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211 std::vector<typename Graph::Node> _queue; |
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212 int _queue_head,_queue_tail,_queue_next_dist; |
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213 int _curr_dist; |
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214 // ///The source node of the last execution. |
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215 // Node source; |
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216 |
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217 ///Creates the maps if necessary. |
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218 |
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219 ///\todo Error if \c G are \c NULL. |
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220 ///\todo Better memory allocation (instead of new). |
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221 void create_maps() |
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222 { |
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223 if(!_pred) { |
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224 local_pred = true; |
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225 _pred = Traits::createPredMap(*G); |
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226 } |
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227 // if(!_predNode) { |
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228 // local_predNode = true; |
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229 // _predNode = Traits::createPredNodeMap(*G); |
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230 // } |
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231 if(!_dist) { |
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232 local_dist = true; |
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233 _dist = Traits::createDistMap(*G); |
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234 } |
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235 if(!_reached) { |
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236 local_reached = true; |
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237 _reached = Traits::createReachedMap(*G); |
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238 } |
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239 if(!_processed) { |
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240 local_processed = true; |
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241 _processed = Traits::createProcessedMap(*G); |
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242 } |
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243 } |
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244 |
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245 public : |
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246 |
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247 ///\name Named template parameters |
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248 |
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249 ///@{ |
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250 |
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251 template <class T> |
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252 struct DefPredMapTraits : public Traits { |
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253 typedef T PredMap; |
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254 static PredMap *createPredMap(const Graph &G) |
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255 { |
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256 throw UninitializedParameter(); |
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257 } |
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258 }; |
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259 ///\ref named-templ-param "Named parameter" for setting PredMap type |
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260 |
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261 ///\ref named-templ-param "Named parameter" for setting PredMap type |
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262 /// |
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263 template <class T> |
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264 class DefPredMap : public Bfs< Graph, |
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265 DefPredMapTraits<T> > { }; |
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266 |
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267 // template <class T> |
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268 // struct DefPredNodeMapTraits : public Traits { |
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269 // typedef T PredNodeMap; |
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270 // static PredNodeMap *createPredNodeMap(const Graph &G) |
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271 // { |
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272 // throw UninitializedParameter(); |
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273 // } |
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274 // }; |
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275 // ///\ref named-templ-param "Named parameter" for setting PredNodeMap type |
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276 |
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277 // ///\ref named-templ-param "Named parameter" for setting PredNodeMap type |
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278 // /// |
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279 // template <class T> |
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280 // class DefPredNodeMap : public Bfs< Graph, |
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281 // LengthMap, |
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282 // DefPredNodeMapTraits<T> > { }; |
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283 |
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284 template <class T> |
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285 struct DefDistMapTraits : public Traits { |
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286 typedef T DistMap; |
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287 static DistMap *createDistMap(const Graph &G) |
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288 { |
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289 throw UninitializedParameter(); |
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290 } |
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291 }; |
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292 ///\ref named-templ-param "Named parameter" for setting DistMap type |
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293 |
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294 ///\ref named-templ-param "Named parameter" for setting DistMap type |
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295 /// |
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296 template <class T> |
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297 class DefDistMap : public Bfs< Graph, |
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298 DefDistMapTraits<T> > { }; |
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299 |
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300 template <class T> |
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301 struct DefReachedMapTraits : public Traits { |
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302 typedef T ReachedMap; |
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303 static ReachedMap *createReachedMap(const Graph &G) |
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304 { |
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305 throw UninitializedParameter(); |
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306 } |
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307 }; |
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308 ///\ref named-templ-param "Named parameter" for setting ReachedMap type |
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309 |
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310 ///\ref named-templ-param "Named parameter" for setting ReachedMap type |
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311 /// |
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312 template <class T> |
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313 class DefReachedMap : public Bfs< Graph, |
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314 DefReachedMapTraits<T> > { }; |
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315 |
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316 struct DefGraphReachedMapTraits : public Traits { |
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317 typedef typename Graph::template NodeMap<bool> ReachedMap; |
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318 static ReachedMap *createReachedMap(const Graph &G) |
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319 { |
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320 return new ReachedMap(G); |
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321 } |
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322 }; |
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323 template <class T> |
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324 struct DefProcessedMapTraits : public Traits { |
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325 typedef T ProcessedMap; |
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326 static ProcessedMap *createProcessedMap(const Graph &G) |
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327 { |
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328 throw UninitializedParameter(); |
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329 } |
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330 }; |
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331 ///\ref named-templ-param "Named parameter" for setting ProcessedMap type |
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332 |
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333 ///\ref named-templ-param "Named parameter" for setting ProcessedMap type |
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334 /// |
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335 template <class T> |
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336 class DefProcessedMap : public Bfs< Graph, |
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337 DefProcessedMapTraits<T> > { }; |
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338 |
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339 struct DefGraphProcessedMapTraits : public Traits { |
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340 typedef typename Graph::template NodeMap<bool> ProcessedMap; |
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341 static ProcessedMap *createProcessedMap(const Graph &G) |
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342 { |
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343 return new ProcessedMap(G); |
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344 } |
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345 }; |
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346 ///\brief \ref named-templ-param "Named parameter" |
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347 ///for setting the ProcessedMap type to be Graph::NodeMap<bool>. |
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348 /// |
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349 ///\ref named-templ-param "Named parameter" |
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350 ///for setting the ProcessedMap type to be Graph::NodeMap<bool>. |
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351 ///If you don't set it explicitly, it will be automatically allocated. |
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352 template <class T> |
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353 class DefProcessedMapToBeDefaultMap : |
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354 public Bfs< Graph, |
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355 DefGraphProcessedMapTraits> { }; |
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356 |
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357 ///@} |
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358 |
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359 public: |
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360 |
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361 ///Constructor. |
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362 |
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363 ///\param _G the graph the algorithm will run on. |
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364 /// |
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365 Bfs(const Graph& _G) : |
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366 G(&_G), |
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367 _pred(NULL), local_pred(false), |
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368 // _predNode(NULL), local_predNode(false), |
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369 _dist(NULL), local_dist(false), |
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370 _reached(NULL), local_reached(false), |
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371 _processed(NULL), local_processed(false) |
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372 { } |
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373 |
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374 ///Destructor. |
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375 ~Bfs() |
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376 { |
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377 if(local_pred) delete _pred; |
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378 // if(local_predNode) delete _predNode; |
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379 if(local_dist) delete _dist; |
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380 if(local_reached) delete _reached; |
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381 if(local_processed) delete _processed; |
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382 } |
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383 |
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384 ///Sets the map storing the predecessor edges. |
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385 |
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386 ///Sets the map storing the predecessor edges. |
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387 ///If you don't use this function before calling \ref run(), |
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388 ///it will allocate one. The destructor deallocates this |
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389 ///automatically allocated map, of course. |
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390 ///\return <tt> (*this) </tt> |
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391 Bfs &predMap(PredMap &m) |
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392 { |
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393 if(local_pred) { |
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394 delete _pred; |
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395 local_pred=false; |
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396 } |
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397 _pred = &m; |
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398 return *this; |
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399 } |
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400 |
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401 ///Sets the map indicating the reached nodes. |
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402 |
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403 ///Sets the map indicating the reached nodes. |
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404 ///If you don't use this function before calling \ref run(), |
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405 ///it will allocate one. The destructor deallocates this |
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406 ///automatically allocated map, of course. |
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407 ///\return <tt> (*this) </tt> |
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408 Bfs &reachedMap(ReachedMap &m) |
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409 { |
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410 if(local_reached) { |
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411 delete _reached; |
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412 local_reached=false; |
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413 } |
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414 _reached = &m; |
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415 return *this; |
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416 } |
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417 |
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418 ///Sets the map indicating the processed nodes. |
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419 |
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420 ///Sets the map indicating the processed nodes. |
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421 ///If you don't use this function before calling \ref run(), |
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422 ///it will allocate one. The destructor deallocates this |
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423 ///automatically allocated map, of course. |
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424 ///\return <tt> (*this) </tt> |
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425 Bfs &processedMap(ProcessedMap &m) |
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426 { |
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427 if(local_processed) { |
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428 delete _processed; |
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429 local_processed=false; |
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430 } |
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431 _processed = &m; |
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432 return *this; |
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433 } |
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434 |
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435 // ///Sets the map storing the predecessor nodes. |
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436 |
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437 // ///Sets the map storing the predecessor nodes. |
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438 // ///If you don't use this function before calling \ref run(), |
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439 // ///it will allocate one. The destructor deallocates this |
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440 // ///automatically allocated map, of course. |
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441 // ///\return <tt> (*this) </tt> |
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442 // Bfs &predNodeMap(PredNodeMap &m) |
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443 // { |
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444 // if(local_predNode) { |
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445 // delete _predNode; |
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446 // local_predNode=false; |
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447 // } |
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448 // _predNode = &m; |
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449 // return *this; |
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450 // } |
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451 |
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452 ///Sets the map storing the distances calculated by the algorithm. |
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453 |
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454 ///Sets the map storing the distances calculated by the algorithm. |
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455 ///If you don't use this function before calling \ref run(), |
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456 ///it will allocate one. The destructor deallocates this |
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457 ///automatically allocated map, of course. |
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458 ///\return <tt> (*this) </tt> |
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459 Bfs &distMap(DistMap &m) |
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460 { |
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461 if(local_dist) { |
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462 delete _dist; |
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463 local_dist=false; |
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464 } |
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465 _dist = &m; |
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466 return *this; |
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467 } |
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468 |
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469 public: |
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470 ///\name Execution control |
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471 ///The simplest way to execute the algorithm is to use |
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472 ///one of the member functions called \c run(...). |
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473 ///\n |
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474 ///If you need more control on the execution, |
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475 ///first you must call \ref init(), then you can add several source nodes |
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476 ///with \ref addSource(). |
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477 ///Finally \ref start() will perform the actual path |
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478 ///computation. |
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479 |
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480 ///@{ |
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481 |
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482 ///Initializes the internal data structures. |
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483 |
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484 ///Initializes the internal data structures. |
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485 /// |
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486 void init() |
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487 { |
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488 create_maps(); |
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489 _queue.resize(countNodes(*G)); |
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490 _queue_head=_queue_tail=0; |
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491 _curr_dist=1; |
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492 for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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493 _pred->set(u,INVALID); |
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494 // _predNode->set(u,INVALID); |
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495 _reached->set(u,false); |
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496 _processed->set(u,false); |
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497 } |
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498 } |
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499 |
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500 ///Adds a new source node. |
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501 |
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502 ///Adds a new source node to the set of nodes to be processed. |
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503 /// |
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504 void addSource(Node s) |
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505 { |
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506 if(!(*_reached)[s]) |
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507 { |
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508 _reached->set(s,true); |
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509 _pred->set(s,INVALID); |
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510 _dist->set(s,0); |
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511 _queue[_queue_head++]=s; |
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512 _queue_next_dist=_queue_head; |
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513 } |
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514 } |
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515 |
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516 ///Processes the next node. |
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517 |
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518 ///Processes the next node. |
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519 /// |
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520 ///\warning The queue must not be empty! |
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521 void processNextNode() |
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522 { |
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523 if(_queue_tail==_queue_next_dist) { |
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524 _curr_dist++; |
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525 _queue_next_dist=_queue_head; |
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526 } |
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527 Node n=_queue[_queue_tail++]; |
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528 _processed->set(n,true); |
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529 Node m; |
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530 for(OutEdgeIt e(*G,n);e!=INVALID;++e) |
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531 if(!(*_reached)[m=G->target(e)]) { |
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532 _queue[_queue_head++]=m; |
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533 _reached->set(m,true); |
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534 _pred->set(m,e); |
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535 // _pred_node->set(m,n); |
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536 _dist->set(m,_curr_dist); |
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537 } |
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538 } |
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539 |
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540 ///\brief Returns \c false if there are nodes |
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541 ///to be processed in the queue |
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542 /// |
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543 ///Returns \c false if there are nodes |
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544 ///to be processed in the queue |
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545 bool emptyQueue() { return _queue_tail==_queue_head; } |
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546 ///Returns the number of the nodes to be processed. |
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547 |
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548 ///Returns the number of the nodes to be processed in the queue. |
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549 /// |
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550 int queueSize() { return _queue_head-_queue_tail; } |
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551 |
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552 ///Executes the algorithm. |
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553 |
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554 ///Executes the algorithm. |
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555 /// |
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556 ///\pre init() must be called and at least one node should be added |
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557 ///with addSource() before using this function. |
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558 /// |
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559 ///This method runs the %BFS algorithm from the root node(s) |
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560 ///in order to |
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561 ///compute the |
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562 ///shortest path to each node. The algorithm computes |
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563 ///- The shortest path tree. |
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564 ///- The distance of each node from the root(s). |
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565 /// |
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566 void start() |
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567 { |
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568 while ( !emptyQueue() ) processNextNode(); |
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569 } |
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570 |
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571 ///Executes the algorithm until \c dest is reached. |
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572 |
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573 ///Executes the algorithm until \c dest is reached. |
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574 /// |
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575 ///\pre init() must be called and at least one node should be added |
|
576 ///with addSource() before using this function. |
|
577 /// |
|
578 ///This method runs the %BFS algorithm from the root node(s) |
|
579 ///in order to |
|
580 ///compute the |
|
581 ///shortest path to \c dest. The algorithm computes |
|
582 ///- The shortest path to \c dest. |
|
583 ///- The distance of \c dest from the root(s). |
|
584 /// |
|
585 void start(Node dest) |
|
586 { |
|
587 while ( !emptyQueue() && _queue[_queue_tail]!=dest ) processNextNode(); |
|
588 } |
|
589 |
|
590 ///Executes the algorithm until a condition is met. |
|
591 |
|
592 ///Executes the algorithm until a condition is met. |
|
593 /// |
|
594 ///\pre init() must be called and at least one node should be added |
|
595 ///with addSource() before using this function. |
|
596 /// |
|
597 ///\param nm must be a bool (or convertible) node map. The algorithm |
|
598 ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>. |
|
599 template<class NM> |
|
600 void start(const NM &nm) |
|
601 { |
|
602 while ( !emptyQueue() && !nm[_queue[_queue_tail]] ) processNextNode(); |
|
603 } |
|
604 |
|
605 ///Runs %BFS algorithm from node \c s. |
|
606 |
|
607 ///This method runs the %BFS algorithm from a root node \c s |
|
608 ///in order to |
|
609 ///compute the |
|
610 ///shortest path to each node. The algorithm computes |
|
611 ///- The shortest path tree. |
|
612 ///- The distance of each node from the root. |
|
613 /// |
|
614 ///\note d.run(s) is just a shortcut of the following code. |
|
615 ///\code |
|
616 /// d.init(); |
|
617 /// d.addSource(s); |
|
618 /// d.start(); |
|
619 ///\endcode |
|
620 void run(Node s) { |
|
621 init(); |
|
622 addSource(s); |
|
623 start(); |
|
624 } |
|
625 |
|
626 ///Finds the shortest path between \c s and \c t. |
|
627 |
|
628 ///Finds the shortest path between \c s and \c t. |
|
629 /// |
|
630 ///\return The length of the shortest s---t path if there exists one, |
|
631 ///0 otherwise. |
|
632 ///\note Apart from the return value, d.run(s) is |
|
633 ///just a shortcut of the following code. |
|
634 ///\code |
|
635 /// d.init(); |
|
636 /// d.addSource(s); |
|
637 /// d.start(t); |
|
638 ///\endcode |
|
639 int run(Node s,Node t) { |
|
640 init(); |
|
641 addSource(s); |
|
642 start(t); |
|
643 return reached(t)?_curr_dist-1+(_queue_tail==_queue_next_dist):0; |
|
644 } |
|
645 |
|
646 ///@} |
|
647 |
|
648 ///\name Query Functions |
|
649 ///The result of the %BFS algorithm can be obtained using these |
|
650 ///functions.\n |
|
651 ///Before the use of these functions, |
|
652 ///either run() or start() must be called. |
|
653 |
|
654 ///@{ |
|
655 |
|
656 ///Copies the shortest path to \c t into \c p |
|
657 |
|
658 ///This function copies the shortest path to \c t into \c p. |
|
659 ///If it \c \t is a source itself or unreachable, then it does not |
|
660 ///alter \c p. |
|
661 ///\todo Is it the right way to handle unreachable nodes? |
|
662 ///\return Returns \c true if a path to \c t was actually copied to \c p, |
|
663 ///\c false otherwise. |
|
664 ///\sa DirPath |
|
665 template<class P> |
|
666 bool getPath(P &p,Node t) |
|
667 { |
|
668 if(reached(t)) { |
|
669 p.clear(); |
|
670 typename P::Builder b(p); |
|
671 for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t)) |
|
672 b.pushFront(pred(t)); |
|
673 b.commit(); |
|
674 return true; |
|
675 } |
|
676 return false; |
|
677 } |
|
678 |
|
679 ///The distance of a node from the root(s). |
|
680 |
|
681 ///Returns the distance of a node from the root(s). |
|
682 ///\pre \ref run() must be called before using this function. |
|
683 ///\warning If node \c v in unreachable from the root(s) the return value |
|
684 ///of this function is undefined. |
|
685 int dist(Node v) const { return (*_dist)[v]; } |
|
686 |
|
687 ///Returns the 'previous edge' of the shortest path tree. |
|
688 |
|
689 ///For a node \c v it returns the 'previous edge' |
|
690 ///of the shortest path tree, |
|
691 ///i.e. it returns the last edge of a shortest path from the root(s) to \c |
|
692 ///v. It is \ref INVALID |
|
693 ///if \c v is unreachable from the root(s) or \c v is a root. The |
|
694 ///shortest path tree used here is equal to the shortest path tree used in |
|
695 ///\ref predNode(Node v). |
|
696 ///\pre Either \ref run() or \ref start() must be called before using |
|
697 ///this function. |
|
698 ///\todo predEdge could be a better name. |
|
699 Edge pred(Node v) const { return (*_pred)[v];} |
|
700 |
|
701 ///Returns the 'previous node' of the shortest path tree. |
|
702 |
|
703 ///For a node \c v it returns the 'previous node' |
|
704 ///of the shortest path tree, |
|
705 ///i.e. it returns the last but one node from a shortest path from the |
|
706 ///root(a) to \c /v. |
|
707 ///It is INVALID if \c v is unreachable from the root(s) or |
|
708 ///if \c v itself a root. |
|
709 ///The shortest path tree used here is equal to the shortest path |
|
710 ///tree used in \ref pred(Node v). |
|
711 ///\pre Either \ref run() or \ref start() must be called before |
|
712 ///using this function. |
|
713 Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
|
714 G->source((*_pred)[v]); } |
|
715 |
|
716 ///Returns a reference to the NodeMap of distances. |
|
717 |
|
718 ///Returns a reference to the NodeMap of distances. |
|
719 ///\pre Either \ref run() or \ref init() must |
|
720 ///be called before using this function. |
|
721 const DistMap &distMap() const { return *_dist;} |
|
722 |
|
723 ///Returns a reference to the shortest path tree map. |
|
724 |
|
725 ///Returns a reference to the NodeMap of the edges of the |
|
726 ///shortest path tree. |
|
727 ///\pre Either \ref run() or \ref init() |
|
728 ///must be called before using this function. |
|
729 const PredMap &predMap() const { return *_pred;} |
|
730 |
|
731 // ///Returns a reference to the map of nodes of shortest paths. |
|
732 |
|
733 // ///Returns a reference to the NodeMap of the last but one nodes of the |
|
734 // ///shortest path tree. |
|
735 // ///\pre \ref run() must be called before using this function. |
|
736 // const PredNodeMap &predNodeMap() const { return *_predNode;} |
|
737 |
|
738 ///Checks if a node is reachable from the root. |
|
739 |
|
740 ///Returns \c true if \c v is reachable from the root. |
|
741 ///\warning The source nodes are indicated as unreached. |
|
742 ///\pre Either \ref run() or \ref start() |
|
743 ///must be called before using this function. |
|
744 /// |
|
745 bool reached(Node v) { return (*_reached)[v]; } |
|
746 |
|
747 ///@} |
|
748 }; |
|
749 |
|
750 ///Default traits class of Bfs function. |
|
751 |
|
752 ///Default traits class of Bfs function. |
|
753 ///\param GR Graph type. |
|
754 template<class GR> |
|
755 struct BfsWizardDefaultTraits |
|
756 { |
|
757 ///The graph type the algorithm runs on. |
|
758 typedef GR Graph; |
|
759 ///\brief The type of the map that stores the last |
|
760 ///edges of the shortest paths. |
|
761 /// |
|
762 ///The type of the map that stores the last |
|
763 ///edges of the shortest paths. |
|
764 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
|
765 /// |
|
766 typedef NullMap<typename Graph::Node,typename GR::Edge> PredMap; |
|
767 ///Instantiates a PredMap. |
|
768 |
|
769 ///This function instantiates a \ref PredMap. |
|
770 ///\param G is the graph, to which we would like to define the PredMap. |
|
771 ///\todo The graph alone may be insufficient to initialize |
|
772 static PredMap *createPredMap(const GR &) |
|
773 { |
|
774 return new PredMap(); |
|
775 } |
|
776 // ///\brief The type of the map that stores the last but one |
|
777 // ///nodes of the shortest paths. |
|
778 // /// |
|
779 // ///The type of the map that stores the last but one |
|
780 // ///nodes of the shortest paths. |
|
781 // ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
|
782 // /// |
|
783 // typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap; |
|
784 // ///Instantiates a PredNodeMap. |
|
785 |
|
786 // ///This function instantiates a \ref PredNodeMap. |
|
787 // ///\param G is the graph, to which |
|
788 // ///we would like to define the \ref PredNodeMap |
|
789 // static PredNodeMap *createPredNodeMap(const GR &G) |
|
790 // { |
|
791 // return new PredNodeMap(); |
|
792 // } |
|
793 |
|
794 ///The type of the map that indicates which nodes are processed. |
|
795 |
|
796 ///The type of the map that indicates which nodes are processed. |
|
797 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
|
798 ///\todo named parameter to set this type, function to read and write. |
|
799 typedef NullMap<typename Graph::Node,bool> ProcessedMap; |
|
800 ///Instantiates a ProcessedMap. |
|
801 |
|
802 ///This function instantiates a \ref ProcessedMap. |
|
803 ///\param G is the graph, to which |
|
804 ///we would like to define the \ref ProcessedMap |
|
805 static ProcessedMap *createProcessedMap(const GR &) |
|
806 { |
|
807 return new ProcessedMap(); |
|
808 } |
|
809 ///The type of the map that indicates which nodes are reached. |
|
810 |
|
811 ///The type of the map that indicates which nodes are reached. |
|
812 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
|
813 ///\todo named parameter to set this type, function to read and write. |
|
814 typedef typename Graph::template NodeMap<bool> ReachedMap; |
|
815 ///Instantiates a ReachedMap. |
|
816 |
|
817 ///This function instantiates a \ref ReachedMap. |
|
818 ///\param G is the graph, to which |
|
819 ///we would like to define the \ref ReachedMap. |
|
820 static ReachedMap *createReachedMap(const GR &G) |
|
821 { |
|
822 return new ReachedMap(G); |
|
823 } |
|
824 ///The type of the map that stores the dists of the nodes. |
|
825 |
|
826 ///The type of the map that stores the dists of the nodes. |
|
827 ///It must meet the \ref concept::WriteMap "WriteMap" concept. |
|
828 /// |
|
829 typedef NullMap<typename Graph::Node,int> DistMap; |
|
830 ///Instantiates a DistMap. |
|
831 |
|
832 ///This function instantiates a \ref DistMap. |
|
833 ///\param G is the graph, to which we would like to define the \ref DistMap |
|
834 static DistMap *createDistMap(const GR &) |
|
835 { |
|
836 return new DistMap(); |
|
837 } |
|
838 }; |
|
839 |
|
840 /// Default traits used by \ref BfsWizard |
|
841 |
|
842 /// To make it easier to use Bfs algorithm |
|
843 ///we have created a wizard class. |
|
844 /// This \ref BfsWizard class needs default traits, |
|
845 ///as well as the \ref Bfs class. |
|
846 /// The \ref BfsWizardBase is a class to be the default traits of the |
|
847 /// \ref BfsWizard class. |
|
848 template<class GR> |
|
849 class BfsWizardBase : public BfsWizardDefaultTraits<GR> |
|
850 { |
|
851 |
|
852 typedef BfsWizardDefaultTraits<GR> Base; |
|
853 protected: |
|
854 /// Type of the nodes in the graph. |
|
855 typedef typename Base::Graph::Node Node; |
|
856 |
|
857 /// Pointer to the underlying graph. |
|
858 void *_g; |
|
859 ///Pointer to the map of reached nodes. |
|
860 void *_reached; |
|
861 ///Pointer to the map of processed nodes. |
|
862 void *_processed; |
|
863 ///Pointer to the map of predecessors edges. |
|
864 void *_pred; |
|
865 // ///Pointer to the map of predecessors nodes. |
|
866 // void *_predNode; |
|
867 ///Pointer to the map of distances. |
|
868 void *_dist; |
|
869 ///Pointer to the source node. |
|
870 Node _source; |
|
871 |
|
872 public: |
|
873 /// Constructor. |
|
874 |
|
875 /// This constructor does not require parameters, therefore it initiates |
|
876 /// all of the attributes to default values (0, INVALID). |
|
877 BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
|
878 // _predNode(0), |
|
879 _dist(0), _source(INVALID) {} |
|
880 |
|
881 /// Constructor. |
|
882 |
|
883 /// This constructor requires some parameters, |
|
884 /// listed in the parameters list. |
|
885 /// Others are initiated to 0. |
|
886 /// \param g is the initial value of \ref _g |
|
887 /// \param s is the initial value of \ref _source |
|
888 BfsWizardBase(const GR &g, Node s=INVALID) : |
|
889 _g((void *)&g), _reached(0), _processed(0), _pred(0), |
|
890 // _predNode(0), |
|
891 _dist(0), _source(s) {} |
|
892 |
|
893 }; |
|
894 |
|
895 /// A class to make the usage of Bfs algorithm easier |
|
896 |
|
897 /// This class is created to make it easier to use Bfs algorithm. |
|
898 /// It uses the functions and features of the plain \ref Bfs, |
|
899 /// but it is much simpler to use it. |
|
900 /// |
|
901 /// Simplicity means that the way to change the types defined |
|
902 /// in the traits class is based on functions that returns the new class |
|
903 /// and not on templatable built-in classes. |
|
904 /// When using the plain \ref Bfs |
|
905 /// the new class with the modified type comes from |
|
906 /// the original class by using the :: |
|
907 /// operator. In the case of \ref BfsWizard only |
|
908 /// a function have to be called and it will |
|
909 /// return the needed class. |
|
910 /// |
|
911 /// It does not have own \ref run method. When its \ref run method is called |
|
912 /// it initiates a plain \ref Bfs class, and calls the \ref Bfs::run |
|
913 /// method of it. |
|
914 template<class TR> |
|
915 class BfsWizard : public TR |
|
916 { |
|
917 typedef TR Base; |
|
918 |
|
919 ///The type of the underlying graph. |
|
920 typedef typename TR::Graph Graph; |
|
921 //\e |
|
922 typedef typename Graph::Node Node; |
|
923 //\e |
|
924 typedef typename Graph::NodeIt NodeIt; |
|
925 //\e |
|
926 typedef typename Graph::Edge Edge; |
|
927 //\e |
|
928 typedef typename Graph::OutEdgeIt OutEdgeIt; |
|
929 |
|
930 ///\brief The type of the map that stores |
|
931 ///the reached nodes |
|
932 typedef typename TR::ReachedMap ReachedMap; |
|
933 ///\brief The type of the map that stores |
|
934 ///the processed nodes |
|
935 typedef typename TR::ProcessedMap ProcessedMap; |
|
936 ///\brief The type of the map that stores the last |
|
937 ///edges of the shortest paths. |
|
938 typedef typename TR::PredMap PredMap; |
|
939 // ///\brief The type of the map that stores the last but one |
|
940 // ///nodes of the shortest paths. |
|
941 // typedef typename TR::PredNodeMap PredNodeMap; |
|
942 ///The type of the map that stores the dists of the nodes. |
|
943 typedef typename TR::DistMap DistMap; |
|
944 |
|
945 public: |
|
946 /// Constructor. |
|
947 BfsWizard() : TR() {} |
|
948 |
|
949 /// Constructor that requires parameters. |
|
950 |
|
951 /// Constructor that requires parameters. |
|
952 /// These parameters will be the default values for the traits class. |
|
953 BfsWizard(const Graph &g, Node s=INVALID) : |
|
954 TR(g,s) {} |
|
955 |
|
956 ///Copy constructor |
|
957 BfsWizard(const TR &b) : TR(b) {} |
|
958 |
|
959 ~BfsWizard() {} |
|
960 |
|
961 ///Runs Bfs algorithm from a given node. |
|
962 |
|
963 ///Runs Bfs algorithm from a given node. |
|
964 ///The node can be given by the \ref source function. |
|
965 void run() |
|
966 { |
|
967 if(Base::_source==INVALID) throw UninitializedParameter(); |
|
968 Bfs<Graph,TR> alg(*(Graph*)Base::_g); |
|
969 if(Base::_reached) |
|
970 alg.reachedMap(*(ReachedMap*)Base::_reached); |
|
971 if(Base::_processed) alg.processedMap(*(ProcessedMap*)Base::_processed); |
|
972 if(Base::_pred) alg.predMap(*(PredMap*)Base::_pred); |
|
973 // if(Base::_predNode) alg.predNodeMap(*(PredNodeMap*)Base::_predNode); |
|
974 if(Base::_dist) alg.distMap(*(DistMap*)Base::_dist); |
|
975 alg.run(Base::_source); |
|
976 } |
|
977 |
|
978 ///Runs Bfs algorithm from the given node. |
|
979 |
|
980 ///Runs Bfs algorithm from the given node. |
|
981 ///\param s is the given source. |
|
982 void run(Node s) |
|
983 { |
|
984 Base::_source=s; |
|
985 run(); |
|
986 } |
|
987 |
|
988 template<class T> |
|
989 struct DefPredMapBase : public Base { |
|
990 typedef T PredMap; |
|
991 static PredMap *createPredMap(const Graph &) { return 0; }; |
|
992 DefPredMapBase(const TR &b) : TR(b) {} |
|
993 }; |
|
994 |
|
995 ///\brief \ref named-templ-param "Named parameter" |
|
996 ///function for setting PredMap |
|
997 /// |
|
998 /// \ref named-templ-param "Named parameter" |
|
999 ///function for setting PredMap |
|
1000 /// |
|
1001 template<class T> |
|
1002 BfsWizard<DefPredMapBase<T> > predMap(const T &t) |
|
1003 { |
|
1004 Base::_pred=(void *)&t; |
|
1005 return BfsWizard<DefPredMapBase<T> >(*this); |
|
1006 } |
|
1007 |
|
1008 |
|
1009 template<class T> |
|
1010 struct DefReachedMapBase : public Base { |
|
1011 typedef T ReachedMap; |
|
1012 static ReachedMap *createReachedMap(const Graph &) { return 0; }; |
|
1013 DefReachedMapBase(const TR &b) : TR(b) {} |
|
1014 }; |
|
1015 |
|
1016 ///\brief \ref named-templ-param "Named parameter" |
|
1017 ///function for setting ReachedMap |
|
1018 /// |
|
1019 /// \ref named-templ-param "Named parameter" |
|
1020 ///function for setting ReachedMap |
|
1021 /// |
|
1022 template<class T> |
|
1023 BfsWizard<DefReachedMapBase<T> > reachedMap(const T &t) |
|
1024 { |
|
1025 Base::_pred=(void *)&t; |
|
1026 return BfsWizard<DefReachedMapBase<T> >(*this); |
|
1027 } |
|
1028 |
|
1029 |
|
1030 template<class T> |
|
1031 struct DefProcessedMapBase : public Base { |
|
1032 typedef T ProcessedMap; |
|
1033 static ProcessedMap *createProcessedMap(const Graph &) { return 0; }; |
|
1034 DefProcessedMapBase(const TR &b) : TR(b) {} |
|
1035 }; |
|
1036 |
|
1037 ///\brief \ref named-templ-param "Named parameter" |
|
1038 ///function for setting ProcessedMap |
|
1039 /// |
|
1040 /// \ref named-templ-param "Named parameter" |
|
1041 ///function for setting ProcessedMap |
|
1042 /// |
|
1043 template<class T> |
|
1044 BfsWizard<DefProcessedMapBase<T> > processedMap(const T &t) |
|
1045 { |
|
1046 Base::_pred=(void *)&t; |
|
1047 return BfsWizard<DefProcessedMapBase<T> >(*this); |
|
1048 } |
|
1049 |
|
1050 |
|
1051 // template<class T> |
|
1052 // struct DefPredNodeMapBase : public Base { |
|
1053 // typedef T PredNodeMap; |
|
1054 // static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; }; |
|
1055 // DefPredNodeMapBase(const TR &b) : TR(b) {} |
|
1056 // }; |
|
1057 |
|
1058 // ///\brief \ref named-templ-param "Named parameter" |
|
1059 // ///function for setting PredNodeMap type |
|
1060 // /// |
|
1061 // /// \ref named-templ-param "Named parameter" |
|
1062 // ///function for setting PredNodeMap type |
|
1063 // /// |
|
1064 // template<class T> |
|
1065 // BfsWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t) |
|
1066 // { |
|
1067 // Base::_predNode=(void *)&t; |
|
1068 // return BfsWizard<DefPredNodeMapBase<T> >(*this); |
|
1069 // } |
|
1070 |
|
1071 template<class T> |
|
1072 struct DefDistMapBase : public Base { |
|
1073 typedef T DistMap; |
|
1074 static DistMap *createDistMap(const Graph &) { return 0; }; |
|
1075 DefDistMapBase(const TR &b) : TR(b) {} |
|
1076 }; |
|
1077 |
|
1078 ///\brief \ref named-templ-param "Named parameter" |
|
1079 ///function for setting DistMap type |
|
1080 /// |
|
1081 /// \ref named-templ-param "Named parameter" |
|
1082 ///function for setting DistMap type |
|
1083 /// |
|
1084 template<class T> |
|
1085 BfsWizard<DefDistMapBase<T> > distMap(const T &t) |
|
1086 { |
|
1087 Base::_dist=(void *)&t; |
|
1088 return BfsWizard<DefDistMapBase<T> >(*this); |
|
1089 } |
|
1090 |
|
1091 /// Sets the source node, from which the Bfs algorithm runs. |
|
1092 |
|
1093 /// Sets the source node, from which the Bfs algorithm runs. |
|
1094 /// \param s is the source node. |
|
1095 BfsWizard<TR> &source(Node s) |
|
1096 { |
|
1097 Base::_source=s; |
|
1098 return *this; |
|
1099 } |
|
1100 |
|
1101 }; |
|
1102 |
|
1103 ///Function type interface for Bfs algorithm. |
|
1104 |
|
1105 /// \ingroup flowalgs |
|
1106 ///Function type interface for Bfs algorithm. |
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1107 /// |
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1108 ///This function also has several |
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1109 ///\ref named-templ-func-param "named parameters", |
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1110 ///they are declared as the members of class \ref BfsWizard. |
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1111 ///The following |
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1112 ///example shows how to use these parameters. |
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1113 ///\code |
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1114 /// bfs(g,source).predMap(preds).run(); |
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1115 ///\endcode |
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1116 ///\warning Don't forget to put the \ref BfsWizard::run() "run()" |
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1117 ///to the end of the parameter list. |
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1118 ///\sa BfsWizard |
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1119 ///\sa Bfs |
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1120 template<class GR> |
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1121 BfsWizard<BfsWizardBase<GR> > |
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1122 bfs(const GR &g,typename GR::Node s=INVALID) |
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1123 { |
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1124 return BfsWizard<BfsWizardBase<GR> >(g,s); |
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1125 } |
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1126 |
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1127 } //END OF NAMESPACE LEMON |
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1128 |
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1129 #endif |
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1130 |
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