1 | /* -*- C++ -*- |
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2 | * |
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3 | * This file is a part of LEMON, a generic C++ optimization library |
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4 | * |
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5 | * Copyright (C) 2003-2008 |
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6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 | * |
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9 | * Permission to use, modify and distribute this software is granted |
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10 | * provided that this copyright notice appears in all copies. For |
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11 | * precise terms see the accompanying LICENSE file. |
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12 | * |
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13 | * This software is provided "AS IS" with no warranty of any kind, |
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14 | * express or implied, and with no claim as to its suitability for any |
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15 | * purpose. |
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16 | * |
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17 | */ |
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18 | |
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19 | #ifndef LEMON_DFS_H |
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20 | #define LEMON_DFS_H |
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21 | |
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22 | ///\ingroup search |
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23 | ///\file |
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24 | ///\brief Dfs algorithm. |
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25 | |
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26 | #include <lemon/list_graph.h> |
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27 | #include <lemon/graph_utils.h> |
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28 | #include <lemon/bits/path_dump.h> |
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29 | #include <lemon/bits/invalid.h> |
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30 | #include <lemon/error.h> |
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31 | #include <lemon/maps.h> |
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32 | |
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33 | #include <lemon/concept_check.h> |
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34 | |
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35 | namespace lemon { |
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36 | |
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37 | |
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38 | ///Default traits class of Dfs class. |
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39 | |
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40 | ///Default traits class of Dfs class. |
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41 | ///\param GR Digraph type. |
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42 | template<class GR> |
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43 | struct DfsDefaultTraits |
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44 | { |
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45 | ///The digraph type the algorithm runs on. |
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46 | typedef GR Digraph; |
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47 | ///\brief The type of the map that stores the last |
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48 | ///arcs of the %DFS paths. |
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49 | /// |
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50 | ///The type of the map that stores the last |
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51 | ///arcs of the %DFS paths. |
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52 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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53 | /// |
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54 | typedef typename Digraph::template NodeMap<typename GR::Arc> PredMap; |
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55 | ///Instantiates a PredMap. |
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56 | |
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57 | ///This function instantiates a \ref PredMap. |
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58 | ///\param G is the digraph, to which we would like to define the PredMap. |
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59 | ///\todo The digraph alone may be insufficient to initialize |
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60 | static PredMap *createPredMap(const GR &G) |
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61 | { |
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62 | return new PredMap(G); |
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63 | } |
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64 | |
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65 | ///The type of the map that indicates which nodes are processed. |
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66 | |
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67 | ///The type of the map that indicates which nodes are processed. |
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68 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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69 | ///\todo named parameter to set this type, function to read and write. |
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70 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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71 | ///Instantiates a ProcessedMap. |
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72 | |
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73 | ///This function instantiates a \ref ProcessedMap. |
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74 | ///\param g is the digraph, to which |
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75 | ///we would like to define the \ref ProcessedMap |
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76 | #ifdef DOXYGEN |
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77 | static ProcessedMap *createProcessedMap(const GR &g) |
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78 | #else |
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79 | static ProcessedMap *createProcessedMap(const GR &) |
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80 | #endif |
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81 | { |
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82 | return new ProcessedMap(); |
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83 | } |
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84 | ///The type of the map that indicates which nodes are reached. |
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85 | |
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86 | ///The type of the map that indicates which nodes are reached. |
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87 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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88 | ///\todo named parameter to set this type, function to read and write. |
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89 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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90 | ///Instantiates a ReachedMap. |
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91 | |
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92 | ///This function instantiates a \ref ReachedMap. |
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93 | ///\param G is the digraph, to which |
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94 | ///we would like to define the \ref ReachedMap. |
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95 | static ReachedMap *createReachedMap(const GR &G) |
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96 | { |
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97 | return new ReachedMap(G); |
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98 | } |
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99 | ///The type of the map that stores the dists of the nodes. |
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100 | |
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101 | ///The type of the map that stores the dists of the nodes. |
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102 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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103 | /// |
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104 | typedef typename Digraph::template NodeMap<int> DistMap; |
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105 | ///Instantiates a DistMap. |
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106 | |
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107 | ///This function instantiates a \ref DistMap. |
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108 | ///\param G is the digraph, to which we would like to define the \ref DistMap |
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109 | static DistMap *createDistMap(const GR &G) |
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110 | { |
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111 | return new DistMap(G); |
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112 | } |
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113 | }; |
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114 | |
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115 | ///%DFS algorithm class. |
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116 | |
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117 | ///\ingroup search |
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118 | ///This class provides an efficient implementation of the %DFS algorithm. |
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119 | /// |
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120 | ///\param GR The digraph type the algorithm runs on. The default value is |
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121 | ///\ref ListDigraph. The value of GR is not used directly by Dfs, it |
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122 | ///is only passed to \ref DfsDefaultTraits. |
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123 | ///\param TR Traits class to set various data types used by the algorithm. |
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124 | ///The default traits class is |
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125 | ///\ref DfsDefaultTraits "DfsDefaultTraits<GR>". |
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126 | ///See \ref DfsDefaultTraits for the documentation of |
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127 | ///a Dfs traits class. |
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128 | /// |
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129 | ///\author Jacint Szabo and Alpar Juttner |
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130 | #ifdef DOXYGEN |
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131 | template <typename GR, |
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132 | typename TR> |
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133 | #else |
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134 | template <typename GR=ListDigraph, |
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135 | typename TR=DfsDefaultTraits<GR> > |
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136 | #endif |
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137 | class Dfs { |
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138 | public: |
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139 | /** |
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140 | * \brief \ref Exception for uninitialized parameters. |
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141 | * |
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142 | * This error represents problems in the initialization |
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143 | * of the parameters of the algorithms. |
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144 | */ |
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145 | class UninitializedParameter : public lemon::UninitializedParameter { |
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146 | public: |
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147 | virtual const char* what() const throw() { |
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148 | return "lemon::Dfs::UninitializedParameter"; |
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149 | } |
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150 | }; |
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151 | |
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152 | typedef TR Traits; |
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153 | ///The type of the underlying digraph. |
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154 | typedef typename TR::Digraph Digraph; |
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155 | ///\e |
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156 | typedef typename Digraph::Node Node; |
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157 | ///\e |
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158 | typedef typename Digraph::NodeIt NodeIt; |
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159 | ///\e |
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160 | typedef typename Digraph::Arc Arc; |
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161 | ///\e |
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162 | typedef typename Digraph::OutArcIt OutArcIt; |
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163 | |
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164 | ///\brief The type of the map that stores the last |
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165 | ///arcs of the %DFS paths. |
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166 | typedef typename TR::PredMap PredMap; |
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167 | ///The type of the map indicating which nodes are reached. |
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168 | typedef typename TR::ReachedMap ReachedMap; |
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169 | ///The type of the map indicating which nodes are processed. |
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170 | typedef typename TR::ProcessedMap ProcessedMap; |
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171 | ///The type of the map that stores the dists of the nodes. |
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172 | typedef typename TR::DistMap DistMap; |
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173 | private: |
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174 | /// Pointer to the underlying digraph. |
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175 | const Digraph *G; |
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176 | ///Pointer to the map of predecessors arcs. |
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177 | PredMap *_pred; |
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178 | ///Indicates if \ref _pred is locally allocated (\c true) or not. |
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179 | bool local_pred; |
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180 | ///Pointer to the map of distances. |
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181 | DistMap *_dist; |
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182 | ///Indicates if \ref _dist is locally allocated (\c true) or not. |
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183 | bool local_dist; |
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184 | ///Pointer to the map of reached status of the nodes. |
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185 | ReachedMap *_reached; |
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186 | ///Indicates if \ref _reached is locally allocated (\c true) or not. |
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187 | bool local_reached; |
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188 | ///Pointer to the map of processed status of the nodes. |
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189 | ProcessedMap *_processed; |
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190 | ///Indicates if \ref _processed is locally allocated (\c true) or not. |
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191 | bool local_processed; |
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192 | |
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193 | std::vector<typename Digraph::OutArcIt> _stack; |
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194 | int _stack_head; |
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195 | |
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196 | ///Creates the maps if necessary. |
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197 | |
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198 | ///\todo Better memory allocation (instead of new). |
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199 | void create_maps() |
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200 | { |
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201 | if(!_pred) { |
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202 | local_pred = true; |
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203 | _pred = Traits::createPredMap(*G); |
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204 | } |
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205 | if(!_dist) { |
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206 | local_dist = true; |
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207 | _dist = Traits::createDistMap(*G); |
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208 | } |
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209 | if(!_reached) { |
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210 | local_reached = true; |
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211 | _reached = Traits::createReachedMap(*G); |
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212 | } |
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213 | if(!_processed) { |
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214 | local_processed = true; |
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215 | _processed = Traits::createProcessedMap(*G); |
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216 | } |
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217 | } |
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218 | |
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219 | protected: |
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220 | |
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221 | Dfs() {} |
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222 | |
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223 | public: |
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224 | |
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225 | typedef Dfs Create; |
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226 | |
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227 | ///\name Named template parameters |
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228 | |
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229 | ///@{ |
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230 | |
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231 | template <class T> |
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232 | struct DefPredMapTraits : public Traits { |
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233 | typedef T PredMap; |
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234 | static PredMap *createPredMap(const Digraph &G) |
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235 | { |
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236 | throw UninitializedParameter(); |
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237 | } |
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238 | }; |
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239 | ///\brief \ref named-templ-param "Named parameter" for setting |
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240 | ///PredMap type |
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241 | /// |
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242 | ///\ref named-templ-param "Named parameter" for setting PredMap type |
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243 | /// |
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244 | template <class T> |
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245 | struct DefPredMap : public Dfs<Digraph, DefPredMapTraits<T> > { |
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246 | typedef Dfs<Digraph, DefPredMapTraits<T> > Create; |
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247 | }; |
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248 | |
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249 | |
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250 | template <class T> |
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251 | struct DefDistMapTraits : public Traits { |
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252 | typedef T DistMap; |
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253 | static DistMap *createDistMap(const Digraph &) |
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254 | { |
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255 | throw UninitializedParameter(); |
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256 | } |
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257 | }; |
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258 | ///\brief \ref named-templ-param "Named parameter" for setting |
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259 | ///DistMap type |
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260 | /// |
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261 | ///\ref named-templ-param "Named parameter" for setting DistMap |
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262 | ///type |
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263 | template <class T> |
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264 | struct DefDistMap { |
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265 | typedef Dfs<Digraph, DefDistMapTraits<T> > Create; |
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266 | }; |
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267 | |
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268 | template <class T> |
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269 | struct DefReachedMapTraits : public Traits { |
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270 | typedef T ReachedMap; |
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271 | static ReachedMap *createReachedMap(const Digraph &) |
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272 | { |
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273 | throw UninitializedParameter(); |
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274 | } |
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275 | }; |
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276 | ///\brief \ref named-templ-param "Named parameter" for setting |
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277 | ///ReachedMap type |
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278 | /// |
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279 | ///\ref named-templ-param "Named parameter" for setting ReachedMap type |
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280 | /// |
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281 | template <class T> |
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282 | struct DefReachedMap : public Dfs< Digraph, DefReachedMapTraits<T> > { |
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283 | typedef Dfs< Digraph, DefReachedMapTraits<T> > Create; |
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284 | }; |
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285 | |
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286 | template <class T> |
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287 | struct DefProcessedMapTraits : public Traits { |
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288 | typedef T ProcessedMap; |
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289 | static ProcessedMap *createProcessedMap(const Digraph &) |
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290 | { |
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291 | throw UninitializedParameter(); |
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292 | } |
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293 | }; |
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294 | ///\brief \ref named-templ-param "Named parameter" for setting |
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295 | ///ProcessedMap type |
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296 | /// |
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297 | ///\ref named-templ-param "Named parameter" for setting ProcessedMap type |
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298 | /// |
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299 | template <class T> |
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300 | struct DefProcessedMap : public Dfs< Digraph, DefProcessedMapTraits<T> > { |
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301 | typedef Dfs< Digraph, DefProcessedMapTraits<T> > Create; |
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302 | }; |
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303 | |
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304 | struct DefDigraphProcessedMapTraits : public Traits { |
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305 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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306 | static ProcessedMap *createProcessedMap(const Digraph &G) |
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307 | { |
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308 | return new ProcessedMap(G); |
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309 | } |
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310 | }; |
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311 | ///\brief \ref named-templ-param "Named parameter" |
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312 | ///for setting the ProcessedMap type to be Digraph::NodeMap<bool>. |
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313 | /// |
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314 | ///\ref named-templ-param "Named parameter" |
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315 | ///for setting the ProcessedMap type to be Digraph::NodeMap<bool>. |
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316 | ///If you don't set it explicitely, it will be automatically allocated. |
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317 | template <class T> |
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318 | class DefProcessedMapToBeDefaultMap : |
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319 | public Dfs< Digraph, DefDigraphProcessedMapTraits> { |
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320 | typedef Dfs< Digraph, DefDigraphProcessedMapTraits> Create; |
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321 | }; |
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322 | |
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323 | ///@} |
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324 | |
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325 | public: |
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326 | |
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327 | ///Constructor. |
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328 | |
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329 | ///\param _G the digraph the algorithm will run on. |
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330 | /// |
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331 | Dfs(const Digraph& _G) : |
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332 | G(&_G), |
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333 | _pred(NULL), local_pred(false), |
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334 | _dist(NULL), local_dist(false), |
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335 | _reached(NULL), local_reached(false), |
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336 | _processed(NULL), local_processed(false) |
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337 | { } |
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338 | |
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339 | ///Destructor. |
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340 | ~Dfs() |
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341 | { |
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342 | if(local_pred) delete _pred; |
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343 | if(local_dist) delete _dist; |
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344 | if(local_reached) delete _reached; |
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345 | if(local_processed) delete _processed; |
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346 | } |
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347 | |
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348 | ///Sets the map storing the predecessor arcs. |
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349 | |
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350 | ///Sets the map storing the predecessor arcs. |
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351 | ///If you don't use this function before calling \ref run(), |
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352 | ///it will allocate one. The destuctor deallocates this |
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353 | ///automatically allocated map, of course. |
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354 | ///\return <tt> (*this) </tt> |
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355 | Dfs &predMap(PredMap &m) |
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356 | { |
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357 | if(local_pred) { |
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358 | delete _pred; |
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359 | local_pred=false; |
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360 | } |
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361 | _pred = &m; |
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362 | return *this; |
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363 | } |
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364 | |
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365 | ///Sets the map storing the distances calculated by the algorithm. |
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366 | |
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367 | ///Sets the map storing the distances calculated by the algorithm. |
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368 | ///If you don't use this function before calling \ref run(), |
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369 | ///it will allocate one. The destuctor deallocates this |
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370 | ///automatically allocated map, of course. |
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371 | ///\return <tt> (*this) </tt> |
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372 | Dfs &distMap(DistMap &m) |
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373 | { |
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374 | if(local_dist) { |
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375 | delete _dist; |
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376 | local_dist=false; |
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377 | } |
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378 | _dist = &m; |
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379 | return *this; |
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380 | } |
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381 | |
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382 | ///Sets the map indicating if a node is reached. |
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383 | |
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384 | ///Sets the map indicating if a node is reached. |
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385 | ///If you don't use this function before calling \ref run(), |
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386 | ///it will allocate one. The destuctor deallocates this |
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387 | ///automatically allocated map, of course. |
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388 | ///\return <tt> (*this) </tt> |
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389 | Dfs &reachedMap(ReachedMap &m) |
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390 | { |
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391 | if(local_reached) { |
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392 | delete _reached; |
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393 | local_reached=false; |
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394 | } |
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395 | _reached = &m; |
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396 | return *this; |
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397 | } |
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398 | |
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399 | ///Sets the map indicating if a node is processed. |
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400 | |
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401 | ///Sets the map indicating if a node is processed. |
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402 | ///If you don't use this function before calling \ref run(), |
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403 | ///it will allocate one. The destuctor deallocates this |
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404 | ///automatically allocated map, of course. |
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405 | ///\return <tt> (*this) </tt> |
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406 | Dfs &processedMap(ProcessedMap &m) |
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407 | { |
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408 | if(local_processed) { |
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409 | delete _processed; |
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410 | local_processed=false; |
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411 | } |
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412 | _processed = &m; |
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413 | return *this; |
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414 | } |
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415 | |
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416 | public: |
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417 | ///\name Execution control |
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418 | ///The simplest way to execute the algorithm is to use |
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419 | ///one of the member functions called \c run(...). |
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420 | ///\n |
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421 | ///If you need more control on the execution, |
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422 | ///first you must call \ref init(), then you can add a source node |
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423 | ///with \ref addSource(). |
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424 | ///Finally \ref start() will perform the actual path |
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425 | ///computation. |
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426 | |
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427 | ///@{ |
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428 | |
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429 | ///Initializes the internal data structures. |
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430 | |
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431 | ///Initializes the internal data structures. |
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432 | /// |
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433 | void init() |
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434 | { |
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435 | create_maps(); |
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436 | _stack.resize(countNodes(*G)); |
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437 | _stack_head=-1; |
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438 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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439 | _pred->set(u,INVALID); |
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440 | // _predNode->set(u,INVALID); |
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441 | _reached->set(u,false); |
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442 | _processed->set(u,false); |
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443 | } |
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444 | } |
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445 | |
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446 | ///Adds a new source node. |
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447 | |
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448 | ///Adds a new source node to the set of nodes to be processed. |
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449 | /// |
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450 | ///\warning dists are wrong (or at least strange) |
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451 | ///in case of multiple sources. |
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452 | void addSource(Node s) |
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453 | { |
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454 | if(!(*_reached)[s]) |
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455 | { |
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456 | _reached->set(s,true); |
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457 | _pred->set(s,INVALID); |
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458 | OutArcIt e(*G,s); |
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459 | if(e!=INVALID) { |
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460 | _stack[++_stack_head]=e; |
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461 | _dist->set(s,_stack_head); |
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462 | } |
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463 | else { |
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464 | _processed->set(s,true); |
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465 | _dist->set(s,0); |
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466 | } |
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467 | } |
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468 | } |
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469 | |
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470 | ///Processes the next arc. |
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471 | |
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472 | ///Processes the next arc. |
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473 | /// |
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474 | ///\return The processed arc. |
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475 | /// |
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476 | ///\pre The stack must not be empty! |
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477 | Arc processNextArc() |
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478 | { |
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479 | Node m; |
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480 | Arc e=_stack[_stack_head]; |
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481 | if(!(*_reached)[m=G->target(e)]) { |
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482 | _pred->set(m,e); |
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483 | _reached->set(m,true); |
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484 | ++_stack_head; |
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485 | _stack[_stack_head] = OutArcIt(*G, m); |
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486 | _dist->set(m,_stack_head); |
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487 | } |
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488 | else { |
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489 | m=G->source(e); |
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490 | ++_stack[_stack_head]; |
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491 | } |
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492 | while(_stack_head>=0 && _stack[_stack_head]==INVALID) { |
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493 | _processed->set(m,true); |
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494 | --_stack_head; |
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495 | if(_stack_head>=0) { |
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496 | m=G->source(_stack[_stack_head]); |
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497 | ++_stack[_stack_head]; |
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498 | } |
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499 | } |
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500 | return e; |
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501 | } |
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502 | ///Next arc to be processed. |
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503 | |
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504 | ///Next arc to be processed. |
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505 | /// |
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506 | ///\return The next arc to be processed or INVALID if the stack is |
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507 | /// empty. |
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508 | OutArcIt nextArc() |
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509 | { |
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510 | return _stack_head>=0?_stack[_stack_head]:INVALID; |
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511 | } |
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512 | |
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513 | ///\brief Returns \c false if there are nodes |
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514 | ///to be processed in the queue |
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515 | /// |
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516 | ///Returns \c false if there are nodes |
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517 | ///to be processed in the queue |
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518 | bool emptyQueue() { return _stack_head<0; } |
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519 | ///Returns the number of the nodes to be processed. |
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520 | |
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521 | ///Returns the number of the nodes to be processed in the queue. |
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522 | int queueSize() { return _stack_head+1; } |
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523 | |
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524 | ///Executes the algorithm. |
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525 | |
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526 | ///Executes the algorithm. |
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527 | /// |
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528 | ///\pre init() must be called and at least one node should be added |
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529 | ///with addSource() before using this function. |
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530 | /// |
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531 | ///This method runs the %DFS algorithm from the root node(s) |
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532 | ///in order to |
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533 | ///compute the |
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534 | ///%DFS path to each node. The algorithm computes |
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535 | ///- The %DFS tree. |
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536 | ///- The distance of each node from the root(s) in the %DFS tree. |
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537 | /// |
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538 | void start() |
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539 | { |
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540 | while ( !emptyQueue() ) processNextArc(); |
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541 | } |
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542 | |
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543 | ///Executes the algorithm until \c dest is reached. |
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544 | |
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545 | ///Executes the algorithm until \c dest is reached. |
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546 | /// |
---|
547 | ///\pre init() must be called and at least one node should be added |
---|
548 | ///with addSource() before using this function. |
---|
549 | /// |
---|
550 | ///This method runs the %DFS algorithm from the root node(s) |
---|
551 | ///in order to |
---|
552 | ///compute the |
---|
553 | ///%DFS path to \c dest. The algorithm computes |
---|
554 | ///- The %DFS path to \c dest. |
---|
555 | ///- The distance of \c dest from the root(s) in the %DFS tree. |
---|
556 | /// |
---|
557 | void start(Node dest) |
---|
558 | { |
---|
559 | while ( !emptyQueue() && G->target(_stack[_stack_head])!=dest ) |
---|
560 | processNextArc(); |
---|
561 | } |
---|
562 | |
---|
563 | ///Executes the algorithm until a condition is met. |
---|
564 | |
---|
565 | ///Executes the algorithm until a condition is met. |
---|
566 | /// |
---|
567 | ///\pre init() must be called and at least one node should be added |
---|
568 | ///with addSource() before using this function. |
---|
569 | /// |
---|
570 | ///\param em must be a bool (or convertible) arc map. The algorithm |
---|
571 | ///will stop when it reaches an arc \c e with <tt>em[e]</tt> true. |
---|
572 | /// |
---|
573 | ///\return The reached arc \c e with <tt>em[e]</tt> true or |
---|
574 | ///\c INVALID if no such arc was found. |
---|
575 | /// |
---|
576 | ///\warning Contrary to \ref Bfs and \ref Dijkstra, \c em is an arc map, |
---|
577 | ///not a node map. |
---|
578 | template<class EM> |
---|
579 | Arc start(const EM &em) |
---|
580 | { |
---|
581 | while ( !emptyQueue() && !em[_stack[_stack_head]] ) |
---|
582 | processNextArc(); |
---|
583 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
584 | } |
---|
585 | |
---|
586 | ///Runs %DFS algorithm to visit all nodes in the digraph. |
---|
587 | |
---|
588 | ///This method runs the %DFS algorithm in order to |
---|
589 | ///compute the |
---|
590 | ///%DFS path to each node. The algorithm computes |
---|
591 | ///- The %DFS tree. |
---|
592 | ///- The distance of each node from the root in the %DFS tree. |
---|
593 | /// |
---|
594 | ///\note d.run() is just a shortcut of the following code. |
---|
595 | ///\code |
---|
596 | /// d.init(); |
---|
597 | /// for (NodeIt it(digraph); it != INVALID; ++it) { |
---|
598 | /// if (!d.reached(it)) { |
---|
599 | /// d.addSource(it); |
---|
600 | /// d.start(); |
---|
601 | /// } |
---|
602 | /// } |
---|
603 | ///\endcode |
---|
604 | void run() { |
---|
605 | init(); |
---|
606 | for (NodeIt it(*G); it != INVALID; ++it) { |
---|
607 | if (!reached(it)) { |
---|
608 | addSource(it); |
---|
609 | start(); |
---|
610 | } |
---|
611 | } |
---|
612 | } |
---|
613 | |
---|
614 | ///Runs %DFS algorithm from node \c s. |
---|
615 | |
---|
616 | ///This method runs the %DFS algorithm from a root node \c s |
---|
617 | ///in order to |
---|
618 | ///compute the |
---|
619 | ///%DFS path to each node. The algorithm computes |
---|
620 | ///- The %DFS tree. |
---|
621 | ///- The distance of each node from the root in the %DFS tree. |
---|
622 | /// |
---|
623 | ///\note d.run(s) is just a shortcut of the following code. |
---|
624 | ///\code |
---|
625 | /// d.init(); |
---|
626 | /// d.addSource(s); |
---|
627 | /// d.start(); |
---|
628 | ///\endcode |
---|
629 | void run(Node s) { |
---|
630 | init(); |
---|
631 | addSource(s); |
---|
632 | start(); |
---|
633 | } |
---|
634 | |
---|
635 | ///Finds the %DFS path between \c s and \c t. |
---|
636 | |
---|
637 | ///Finds the %DFS path between \c s and \c t. |
---|
638 | /// |
---|
639 | ///\return The length of the %DFS s---t path if there exists one, |
---|
640 | ///0 otherwise. |
---|
641 | ///\note Apart from the return value, d.run(s,t) is |
---|
642 | ///just a shortcut of the following code. |
---|
643 | ///\code |
---|
644 | /// d.init(); |
---|
645 | /// d.addSource(s); |
---|
646 | /// d.start(t); |
---|
647 | ///\endcode |
---|
648 | int run(Node s,Node t) { |
---|
649 | init(); |
---|
650 | addSource(s); |
---|
651 | start(t); |
---|
652 | return reached(t)?_stack_head+1:0; |
---|
653 | } |
---|
654 | |
---|
655 | ///@} |
---|
656 | |
---|
657 | ///\name Query Functions |
---|
658 | ///The result of the %DFS algorithm can be obtained using these |
---|
659 | ///functions.\n |
---|
660 | ///Before the use of these functions, |
---|
661 | ///either run() or start() must be called. |
---|
662 | |
---|
663 | ///@{ |
---|
664 | |
---|
665 | typedef PredMapPath<Digraph, PredMap> Path; |
---|
666 | |
---|
667 | ///Gives back the shortest path. |
---|
668 | |
---|
669 | ///Gives back the shortest path. |
---|
670 | ///\pre The \c t should be reachable from the source. |
---|
671 | Path path(Node t) |
---|
672 | { |
---|
673 | return Path(*G, *_pred, t); |
---|
674 | } |
---|
675 | |
---|
676 | ///The distance of a node from the root(s). |
---|
677 | |
---|
678 | ///Returns the distance of a node from the root(s). |
---|
679 | ///\pre \ref run() must be called before using this function. |
---|
680 | ///\warning If node \c v is unreachable from the root(s) then the return |
---|
681 | ///value of this funcion is undefined. |
---|
682 | int dist(Node v) const { return (*_dist)[v]; } |
---|
683 | |
---|
684 | ///Returns the 'previous arc' of the %DFS tree. |
---|
685 | |
---|
686 | ///For a node \c v it returns the 'previous arc' |
---|
687 | ///of the %DFS path, |
---|
688 | ///i.e. it returns the last arc of a %DFS path from the root(s) to \c |
---|
689 | ///v. It is \ref INVALID |
---|
690 | ///if \c v is unreachable from the root(s) or \c v is a root. The |
---|
691 | ///%DFS tree used here is equal to the %DFS tree used in |
---|
692 | ///\ref predNode(). |
---|
693 | ///\pre Either \ref run() or \ref start() must be called before using |
---|
694 | ///this function. |
---|
695 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
696 | |
---|
697 | ///Returns the 'previous node' of the %DFS tree. |
---|
698 | |
---|
699 | ///For a node \c v it returns the 'previous node' |
---|
700 | ///of the %DFS tree, |
---|
701 | ///i.e. it returns the last but one node from a %DFS path from the |
---|
702 | ///root(s) to \c v. |
---|
703 | ///It is INVALID if \c v is unreachable from the root(s) or |
---|
704 | ///if \c v itself a root. |
---|
705 | ///The %DFS tree used here is equal to the %DFS |
---|
706 | ///tree used in \ref predArc(). |
---|
707 | ///\pre Either \ref run() or \ref start() must be called before |
---|
708 | ///using this function. |
---|
709 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
710 | G->source((*_pred)[v]); } |
---|
711 | |
---|
712 | ///Returns a reference to the NodeMap of distances. |
---|
713 | |
---|
714 | ///Returns a reference to the NodeMap of distances. |
---|
715 | ///\pre Either \ref run() or \ref init() must |
---|
716 | ///be called before using this function. |
---|
717 | const DistMap &distMap() const { return *_dist;} |
---|
718 | |
---|
719 | ///Returns a reference to the %DFS arc-tree map. |
---|
720 | |
---|
721 | ///Returns a reference to the NodeMap of the arcs of the |
---|
722 | ///%DFS tree. |
---|
723 | ///\pre Either \ref run() or \ref init() |
---|
724 | ///must be called before using this function. |
---|
725 | const PredMap &predMap() const { return *_pred;} |
---|
726 | |
---|
727 | ///Checks if a node is reachable from the root. |
---|
728 | |
---|
729 | ///Returns \c true if \c v is reachable from the root(s). |
---|
730 | ///\warning The source nodes are inditated as unreachable. |
---|
731 | ///\pre Either \ref run() or \ref start() |
---|
732 | ///must be called before using this function. |
---|
733 | /// |
---|
734 | bool reached(Node v) { return (*_reached)[v]; } |
---|
735 | |
---|
736 | ///@} |
---|
737 | }; |
---|
738 | |
---|
739 | ///Default traits class of Dfs function. |
---|
740 | |
---|
741 | ///Default traits class of Dfs function. |
---|
742 | ///\param GR Digraph type. |
---|
743 | template<class GR> |
---|
744 | struct DfsWizardDefaultTraits |
---|
745 | { |
---|
746 | ///The digraph type the algorithm runs on. |
---|
747 | typedef GR Digraph; |
---|
748 | ///\brief The type of the map that stores the last |
---|
749 | ///arcs of the %DFS paths. |
---|
750 | /// |
---|
751 | ///The type of the map that stores the last |
---|
752 | ///arcs of the %DFS paths. |
---|
753 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
754 | /// |
---|
755 | typedef NullMap<typename Digraph::Node,typename GR::Arc> PredMap; |
---|
756 | ///Instantiates a PredMap. |
---|
757 | |
---|
758 | ///This function instantiates a \ref PredMap. |
---|
759 | ///\param g is the digraph, to which we would like to define the PredMap. |
---|
760 | ///\todo The digraph alone may be insufficient to initialize |
---|
761 | #ifdef DOXYGEN |
---|
762 | static PredMap *createPredMap(const GR &g) |
---|
763 | #else |
---|
764 | static PredMap *createPredMap(const GR &) |
---|
765 | #endif |
---|
766 | { |
---|
767 | return new PredMap(); |
---|
768 | } |
---|
769 | |
---|
770 | ///The type of the map that indicates which nodes are processed. |
---|
771 | |
---|
772 | ///The type of the map that indicates which nodes are processed. |
---|
773 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
774 | ///\todo named parameter to set this type, function to read and write. |
---|
775 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
776 | ///Instantiates a ProcessedMap. |
---|
777 | |
---|
778 | ///This function instantiates a \ref ProcessedMap. |
---|
779 | ///\param g is the digraph, to which |
---|
780 | ///we would like to define the \ref ProcessedMap |
---|
781 | #ifdef DOXYGEN |
---|
782 | static ProcessedMap *createProcessedMap(const GR &g) |
---|
783 | #else |
---|
784 | static ProcessedMap *createProcessedMap(const GR &) |
---|
785 | #endif |
---|
786 | { |
---|
787 | return new ProcessedMap(); |
---|
788 | } |
---|
789 | ///The type of the map that indicates which nodes are reached. |
---|
790 | |
---|
791 | ///The type of the map that indicates which nodes are reached. |
---|
792 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
793 | ///\todo named parameter to set this type, function to read and write. |
---|
794 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
795 | ///Instantiates a ReachedMap. |
---|
796 | |
---|
797 | ///This function instantiates a \ref ReachedMap. |
---|
798 | ///\param G is the digraph, to which |
---|
799 | ///we would like to define the \ref ReachedMap. |
---|
800 | static ReachedMap *createReachedMap(const GR &G) |
---|
801 | { |
---|
802 | return new ReachedMap(G); |
---|
803 | } |
---|
804 | ///The type of the map that stores the dists of the nodes. |
---|
805 | |
---|
806 | ///The type of the map that stores the dists of the nodes. |
---|
807 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
808 | /// |
---|
809 | typedef NullMap<typename Digraph::Node,int> DistMap; |
---|
810 | ///Instantiates a DistMap. |
---|
811 | |
---|
812 | ///This function instantiates a \ref DistMap. |
---|
813 | ///\param g is the digraph, to which we would like to define the \ref DistMap |
---|
814 | #ifdef DOXYGEN |
---|
815 | static DistMap *createDistMap(const GR &g) |
---|
816 | #else |
---|
817 | static DistMap *createDistMap(const GR &) |
---|
818 | #endif |
---|
819 | { |
---|
820 | return new DistMap(); |
---|
821 | } |
---|
822 | }; |
---|
823 | |
---|
824 | /// Default traits used by \ref DfsWizard |
---|
825 | |
---|
826 | /// To make it easier to use Dfs algorithm |
---|
827 | ///we have created a wizard class. |
---|
828 | /// This \ref DfsWizard class needs default traits, |
---|
829 | ///as well as the \ref Dfs class. |
---|
830 | /// The \ref DfsWizardBase is a class to be the default traits of the |
---|
831 | /// \ref DfsWizard class. |
---|
832 | template<class GR> |
---|
833 | class DfsWizardBase : public DfsWizardDefaultTraits<GR> |
---|
834 | { |
---|
835 | |
---|
836 | typedef DfsWizardDefaultTraits<GR> Base; |
---|
837 | protected: |
---|
838 | /// Type of the nodes in the digraph. |
---|
839 | typedef typename Base::Digraph::Node Node; |
---|
840 | |
---|
841 | /// Pointer to the underlying digraph. |
---|
842 | void *_g; |
---|
843 | ///Pointer to the map of reached nodes. |
---|
844 | void *_reached; |
---|
845 | ///Pointer to the map of processed nodes. |
---|
846 | void *_processed; |
---|
847 | ///Pointer to the map of predecessors arcs. |
---|
848 | void *_pred; |
---|
849 | ///Pointer to the map of distances. |
---|
850 | void *_dist; |
---|
851 | ///Pointer to the source node. |
---|
852 | Node _source; |
---|
853 | |
---|
854 | public: |
---|
855 | /// Constructor. |
---|
856 | |
---|
857 | /// This constructor does not require parameters, therefore it initiates |
---|
858 | /// all of the attributes to default values (0, INVALID). |
---|
859 | DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
860 | _dist(0), _source(INVALID) {} |
---|
861 | |
---|
862 | /// Constructor. |
---|
863 | |
---|
864 | /// This constructor requires some parameters, |
---|
865 | /// listed in the parameters list. |
---|
866 | /// Others are initiated to 0. |
---|
867 | /// \param g is the initial value of \ref _g |
---|
868 | /// \param s is the initial value of \ref _source |
---|
869 | DfsWizardBase(const GR &g, Node s=INVALID) : |
---|
870 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
---|
871 | _reached(0), _processed(0), _pred(0), _dist(0), _source(s) {} |
---|
872 | |
---|
873 | }; |
---|
874 | |
---|
875 | /// A class to make the usage of the Dfs algorithm easier |
---|
876 | |
---|
877 | /// This class is created to make it easier to use the Dfs algorithm. |
---|
878 | /// It uses the functions and features of the plain \ref Dfs, |
---|
879 | /// but it is much simpler to use it. |
---|
880 | /// |
---|
881 | /// Simplicity means that the way to change the types defined |
---|
882 | /// in the traits class is based on functions that returns the new class |
---|
883 | /// and not on templatable built-in classes. |
---|
884 | /// When using the plain \ref Dfs |
---|
885 | /// the new class with the modified type comes from |
---|
886 | /// the original class by using the :: |
---|
887 | /// operator. In the case of \ref DfsWizard only |
---|
888 | /// a function have to be called and it will |
---|
889 | /// return the needed class. |
---|
890 | /// |
---|
891 | /// It does not have own \ref run method. When its \ref run method is called |
---|
892 | /// it initiates a plain \ref Dfs object, and calls the \ref Dfs::run |
---|
893 | /// method of it. |
---|
894 | template<class TR> |
---|
895 | class DfsWizard : public TR |
---|
896 | { |
---|
897 | typedef TR Base; |
---|
898 | |
---|
899 | ///The type of the underlying digraph. |
---|
900 | typedef typename TR::Digraph Digraph; |
---|
901 | //\e |
---|
902 | typedef typename Digraph::Node Node; |
---|
903 | //\e |
---|
904 | typedef typename Digraph::NodeIt NodeIt; |
---|
905 | //\e |
---|
906 | typedef typename Digraph::Arc Arc; |
---|
907 | //\e |
---|
908 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
909 | |
---|
910 | ///\brief The type of the map that stores |
---|
911 | ///the reached nodes |
---|
912 | typedef typename TR::ReachedMap ReachedMap; |
---|
913 | ///\brief The type of the map that stores |
---|
914 | ///the processed nodes |
---|
915 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
916 | ///\brief The type of the map that stores the last |
---|
917 | ///arcs of the %DFS paths. |
---|
918 | typedef typename TR::PredMap PredMap; |
---|
919 | ///The type of the map that stores the distances of the nodes. |
---|
920 | typedef typename TR::DistMap DistMap; |
---|
921 | |
---|
922 | public: |
---|
923 | /// Constructor. |
---|
924 | DfsWizard() : TR() {} |
---|
925 | |
---|
926 | /// Constructor that requires parameters. |
---|
927 | |
---|
928 | /// Constructor that requires parameters. |
---|
929 | /// These parameters will be the default values for the traits class. |
---|
930 | DfsWizard(const Digraph &g, Node s=INVALID) : |
---|
931 | TR(g,s) {} |
---|
932 | |
---|
933 | ///Copy constructor |
---|
934 | DfsWizard(const TR &b) : TR(b) {} |
---|
935 | |
---|
936 | ~DfsWizard() {} |
---|
937 | |
---|
938 | ///Runs Dfs algorithm from a given node. |
---|
939 | |
---|
940 | ///Runs Dfs algorithm from a given node. |
---|
941 | ///The node can be given by the \ref source function. |
---|
942 | void run() |
---|
943 | { |
---|
944 | if(Base::_source==INVALID) throw UninitializedParameter(); |
---|
945 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
946 | if(Base::_reached) |
---|
947 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
948 | if(Base::_processed) |
---|
949 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
950 | if(Base::_pred) |
---|
951 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
952 | if(Base::_dist) |
---|
953 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
954 | alg.run(Base::_source); |
---|
955 | } |
---|
956 | |
---|
957 | ///Runs Dfs algorithm from the given node. |
---|
958 | |
---|
959 | ///Runs Dfs algorithm from the given node. |
---|
960 | ///\param s is the given source. |
---|
961 | void run(Node s) |
---|
962 | { |
---|
963 | Base::_source=s; |
---|
964 | run(); |
---|
965 | } |
---|
966 | |
---|
967 | template<class T> |
---|
968 | struct DefPredMapBase : public Base { |
---|
969 | typedef T PredMap; |
---|
970 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
971 | DefPredMapBase(const TR &b) : TR(b) {} |
---|
972 | }; |
---|
973 | |
---|
974 | ///\brief \ref named-templ-param "Named parameter" |
---|
975 | ///function for setting PredMap type |
---|
976 | /// |
---|
977 | /// \ref named-templ-param "Named parameter" |
---|
978 | ///function for setting PredMap type |
---|
979 | /// |
---|
980 | template<class T> |
---|
981 | DfsWizard<DefPredMapBase<T> > predMap(const T &t) |
---|
982 | { |
---|
983 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
984 | return DfsWizard<DefPredMapBase<T> >(*this); |
---|
985 | } |
---|
986 | |
---|
987 | |
---|
988 | template<class T> |
---|
989 | struct DefReachedMapBase : public Base { |
---|
990 | typedef T ReachedMap; |
---|
991 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
992 | DefReachedMapBase(const TR &b) : TR(b) {} |
---|
993 | }; |
---|
994 | |
---|
995 | ///\brief \ref named-templ-param "Named parameter" |
---|
996 | ///function for setting ReachedMap |
---|
997 | /// |
---|
998 | /// \ref named-templ-param "Named parameter" |
---|
999 | ///function for setting ReachedMap |
---|
1000 | /// |
---|
1001 | template<class T> |
---|
1002 | DfsWizard<DefReachedMapBase<T> > reachedMap(const T &t) |
---|
1003 | { |
---|
1004 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
1005 | return DfsWizard<DefReachedMapBase<T> >(*this); |
---|
1006 | } |
---|
1007 | |
---|
1008 | |
---|
1009 | template<class T> |
---|
1010 | struct DefProcessedMapBase : public Base { |
---|
1011 | typedef T ProcessedMap; |
---|
1012 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
1013 | DefProcessedMapBase(const TR &b) : TR(b) {} |
---|
1014 | }; |
---|
1015 | |
---|
1016 | ///\brief \ref named-templ-param "Named parameter" |
---|
1017 | ///function for setting ProcessedMap |
---|
1018 | /// |
---|
1019 | /// \ref named-templ-param "Named parameter" |
---|
1020 | ///function for setting ProcessedMap |
---|
1021 | /// |
---|
1022 | template<class T> |
---|
1023 | DfsWizard<DefProcessedMapBase<T> > processedMap(const T &t) |
---|
1024 | { |
---|
1025 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
1026 | return DfsWizard<DefProcessedMapBase<T> >(*this); |
---|
1027 | } |
---|
1028 | |
---|
1029 | template<class T> |
---|
1030 | struct DefDistMapBase : public Base { |
---|
1031 | typedef T DistMap; |
---|
1032 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
1033 | DefDistMapBase(const TR &b) : TR(b) {} |
---|
1034 | }; |
---|
1035 | |
---|
1036 | ///\brief \ref named-templ-param "Named parameter" |
---|
1037 | ///function for setting DistMap type |
---|
1038 | /// |
---|
1039 | /// \ref named-templ-param "Named parameter" |
---|
1040 | ///function for setting DistMap type |
---|
1041 | /// |
---|
1042 | template<class T> |
---|
1043 | DfsWizard<DefDistMapBase<T> > distMap(const T &t) |
---|
1044 | { |
---|
1045 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
1046 | return DfsWizard<DefDistMapBase<T> >(*this); |
---|
1047 | } |
---|
1048 | |
---|
1049 | /// Sets the source node, from which the Dfs algorithm runs. |
---|
1050 | |
---|
1051 | /// Sets the source node, from which the Dfs algorithm runs. |
---|
1052 | /// \param s is the source node. |
---|
1053 | DfsWizard<TR> &source(Node s) |
---|
1054 | { |
---|
1055 | Base::_source=s; |
---|
1056 | return *this; |
---|
1057 | } |
---|
1058 | |
---|
1059 | }; |
---|
1060 | |
---|
1061 | ///Function type interface for Dfs algorithm. |
---|
1062 | |
---|
1063 | ///\ingroup search |
---|
1064 | ///Function type interface for Dfs algorithm. |
---|
1065 | /// |
---|
1066 | ///This function also has several |
---|
1067 | ///\ref named-templ-func-param "named parameters", |
---|
1068 | ///they are declared as the members of class \ref DfsWizard. |
---|
1069 | ///The following |
---|
1070 | ///example shows how to use these parameters. |
---|
1071 | ///\code |
---|
1072 | /// dfs(g,source).predMap(preds).run(); |
---|
1073 | ///\endcode |
---|
1074 | ///\warning Don't forget to put the \ref DfsWizard::run() "run()" |
---|
1075 | ///to the end of the parameter list. |
---|
1076 | ///\sa DfsWizard |
---|
1077 | ///\sa Dfs |
---|
1078 | template<class GR> |
---|
1079 | DfsWizard<DfsWizardBase<GR> > |
---|
1080 | dfs(const GR &g,typename GR::Node s=INVALID) |
---|
1081 | { |
---|
1082 | return DfsWizard<DfsWizardBase<GR> >(g,s); |
---|
1083 | } |
---|
1084 | |
---|
1085 | #ifdef DOXYGEN |
---|
1086 | /// \brief Visitor class for dfs. |
---|
1087 | /// |
---|
1088 | /// It gives a simple interface for a functional interface for dfs |
---|
1089 | /// traversal. The traversal on a linear data structure. |
---|
1090 | template <typename _Digraph> |
---|
1091 | struct DfsVisitor { |
---|
1092 | typedef _Digraph Digraph; |
---|
1093 | typedef typename Digraph::Arc Arc; |
---|
1094 | typedef typename Digraph::Node Node; |
---|
1095 | /// \brief Called when the arc reach a node. |
---|
1096 | /// |
---|
1097 | /// It is called when the dfs find an arc which target is not |
---|
1098 | /// reached yet. |
---|
1099 | void discover(const Arc& arc) {} |
---|
1100 | /// \brief Called when the node reached first time. |
---|
1101 | /// |
---|
1102 | /// It is Called when the node reached first time. |
---|
1103 | void reach(const Node& node) {} |
---|
1104 | /// \brief Called when we step back on an arc. |
---|
1105 | /// |
---|
1106 | /// It is called when the dfs should step back on the arc. |
---|
1107 | void backtrack(const Arc& arc) {} |
---|
1108 | /// \brief Called when we step back from the node. |
---|
1109 | /// |
---|
1110 | /// It is called when we step back from the node. |
---|
1111 | void leave(const Node& node) {} |
---|
1112 | /// \brief Called when the arc examined but target of the arc |
---|
1113 | /// already discovered. |
---|
1114 | /// |
---|
1115 | /// It called when the arc examined but the target of the arc |
---|
1116 | /// already discovered. |
---|
1117 | void examine(const Arc& arc) {} |
---|
1118 | /// \brief Called for the source node of the dfs. |
---|
1119 | /// |
---|
1120 | /// It is called for the source node of the dfs. |
---|
1121 | void start(const Node& node) {} |
---|
1122 | /// \brief Called when we leave the source node of the dfs. |
---|
1123 | /// |
---|
1124 | /// It is called when we leave the source node of the dfs. |
---|
1125 | void stop(const Node& node) {} |
---|
1126 | |
---|
1127 | }; |
---|
1128 | #else |
---|
1129 | template <typename _Digraph> |
---|
1130 | struct DfsVisitor { |
---|
1131 | typedef _Digraph Digraph; |
---|
1132 | typedef typename Digraph::Arc Arc; |
---|
1133 | typedef typename Digraph::Node Node; |
---|
1134 | void discover(const Arc&) {} |
---|
1135 | void reach(const Node&) {} |
---|
1136 | void backtrack(const Arc&) {} |
---|
1137 | void leave(const Node&) {} |
---|
1138 | void examine(const Arc&) {} |
---|
1139 | void start(const Node&) {} |
---|
1140 | void stop(const Node&) {} |
---|
1141 | |
---|
1142 | template <typename _Visitor> |
---|
1143 | struct Constraints { |
---|
1144 | void constraints() { |
---|
1145 | Arc arc; |
---|
1146 | Node node; |
---|
1147 | visitor.discover(arc); |
---|
1148 | visitor.reach(node); |
---|
1149 | visitor.backtrack(arc); |
---|
1150 | visitor.leave(node); |
---|
1151 | visitor.examine(arc); |
---|
1152 | visitor.start(node); |
---|
1153 | visitor.stop(arc); |
---|
1154 | } |
---|
1155 | _Visitor& visitor; |
---|
1156 | }; |
---|
1157 | }; |
---|
1158 | #endif |
---|
1159 | |
---|
1160 | /// \brief Default traits class of DfsVisit class. |
---|
1161 | /// |
---|
1162 | /// Default traits class of DfsVisit class. |
---|
1163 | /// \param _Digraph Digraph type. |
---|
1164 | template<class _Digraph> |
---|
1165 | struct DfsVisitDefaultTraits { |
---|
1166 | |
---|
1167 | /// \brief The digraph type the algorithm runs on. |
---|
1168 | typedef _Digraph Digraph; |
---|
1169 | |
---|
1170 | /// \brief The type of the map that indicates which nodes are reached. |
---|
1171 | /// |
---|
1172 | /// The type of the map that indicates which nodes are reached. |
---|
1173 | /// It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
1174 | /// \todo named parameter to set this type, function to read and write. |
---|
1175 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
1176 | |
---|
1177 | /// \brief Instantiates a ReachedMap. |
---|
1178 | /// |
---|
1179 | /// This function instantiates a \ref ReachedMap. |
---|
1180 | /// \param digraph is the digraph, to which |
---|
1181 | /// we would like to define the \ref ReachedMap. |
---|
1182 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
1183 | return new ReachedMap(digraph); |
---|
1184 | } |
---|
1185 | |
---|
1186 | }; |
---|
1187 | |
---|
1188 | /// %DFS Visit algorithm class. |
---|
1189 | |
---|
1190 | /// \ingroup search |
---|
1191 | /// This class provides an efficient implementation of the %DFS algorithm |
---|
1192 | /// with visitor interface. |
---|
1193 | /// |
---|
1194 | /// The %DfsVisit class provides an alternative interface to the Dfs |
---|
1195 | /// class. It works with callback mechanism, the DfsVisit object calls |
---|
1196 | /// on every dfs event the \c Visitor class member functions. |
---|
1197 | /// |
---|
1198 | /// \param _Digraph The digraph type the algorithm runs on. The default value is |
---|
1199 | /// \ref ListDigraph. The value of _Digraph is not used directly by Dfs, it |
---|
1200 | /// is only passed to \ref DfsDefaultTraits. |
---|
1201 | /// \param _Visitor The Visitor object for the algorithm. The |
---|
1202 | /// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty Visitor which |
---|
1203 | /// does not observe the Dfs events. If you want to observe the dfs |
---|
1204 | /// events you should implement your own Visitor class. |
---|
1205 | /// \param _Traits Traits class to set various data types used by the |
---|
1206 | /// algorithm. The default traits class is |
---|
1207 | /// \ref DfsVisitDefaultTraits "DfsVisitDefaultTraits<_Digraph>". |
---|
1208 | /// See \ref DfsVisitDefaultTraits for the documentation of |
---|
1209 | /// a Dfs visit traits class. |
---|
1210 | /// |
---|
1211 | /// \author Jacint Szabo, Alpar Juttner and Balazs Dezso |
---|
1212 | #ifdef DOXYGEN |
---|
1213 | template <typename _Digraph, typename _Visitor, typename _Traits> |
---|
1214 | #else |
---|
1215 | template <typename _Digraph = ListDigraph, |
---|
1216 | typename _Visitor = DfsVisitor<_Digraph>, |
---|
1217 | typename _Traits = DfsDefaultTraits<_Digraph> > |
---|
1218 | #endif |
---|
1219 | class DfsVisit { |
---|
1220 | public: |
---|
1221 | |
---|
1222 | /// \brief \ref Exception for uninitialized parameters. |
---|
1223 | /// |
---|
1224 | /// This error represents problems in the initialization |
---|
1225 | /// of the parameters of the algorithms. |
---|
1226 | class UninitializedParameter : public lemon::UninitializedParameter { |
---|
1227 | public: |
---|
1228 | virtual const char* what() const throw() |
---|
1229 | { |
---|
1230 | return "lemon::DfsVisit::UninitializedParameter"; |
---|
1231 | } |
---|
1232 | }; |
---|
1233 | |
---|
1234 | typedef _Traits Traits; |
---|
1235 | |
---|
1236 | typedef typename Traits::Digraph Digraph; |
---|
1237 | |
---|
1238 | typedef _Visitor Visitor; |
---|
1239 | |
---|
1240 | ///The type of the map indicating which nodes are reached. |
---|
1241 | typedef typename Traits::ReachedMap ReachedMap; |
---|
1242 | |
---|
1243 | private: |
---|
1244 | |
---|
1245 | typedef typename Digraph::Node Node; |
---|
1246 | typedef typename Digraph::NodeIt NodeIt; |
---|
1247 | typedef typename Digraph::Arc Arc; |
---|
1248 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
1249 | |
---|
1250 | /// Pointer to the underlying digraph. |
---|
1251 | const Digraph *_digraph; |
---|
1252 | /// Pointer to the visitor object. |
---|
1253 | Visitor *_visitor; |
---|
1254 | ///Pointer to the map of reached status of the nodes. |
---|
1255 | ReachedMap *_reached; |
---|
1256 | ///Indicates if \ref _reached is locally allocated (\c true) or not. |
---|
1257 | bool local_reached; |
---|
1258 | |
---|
1259 | std::vector<typename Digraph::Arc> _stack; |
---|
1260 | int _stack_head; |
---|
1261 | |
---|
1262 | /// \brief Creates the maps if necessary. |
---|
1263 | /// |
---|
1264 | /// Creates the maps if necessary. |
---|
1265 | void create_maps() { |
---|
1266 | if(!_reached) { |
---|
1267 | local_reached = true; |
---|
1268 | _reached = Traits::createReachedMap(*_digraph); |
---|
1269 | } |
---|
1270 | } |
---|
1271 | |
---|
1272 | protected: |
---|
1273 | |
---|
1274 | DfsVisit() {} |
---|
1275 | |
---|
1276 | public: |
---|
1277 | |
---|
1278 | typedef DfsVisit Create; |
---|
1279 | |
---|
1280 | /// \name Named template parameters |
---|
1281 | |
---|
1282 | ///@{ |
---|
1283 | template <class T> |
---|
1284 | struct DefReachedMapTraits : public Traits { |
---|
1285 | typedef T ReachedMap; |
---|
1286 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
1287 | throw UninitializedParameter(); |
---|
1288 | } |
---|
1289 | }; |
---|
1290 | /// \brief \ref named-templ-param "Named parameter" for setting |
---|
1291 | /// ReachedMap type |
---|
1292 | /// |
---|
1293 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type |
---|
1294 | template <class T> |
---|
1295 | struct DefReachedMap : public DfsVisit< Digraph, Visitor, |
---|
1296 | DefReachedMapTraits<T> > { |
---|
1297 | typedef DfsVisit< Digraph, Visitor, DefReachedMapTraits<T> > Create; |
---|
1298 | }; |
---|
1299 | ///@} |
---|
1300 | |
---|
1301 | public: |
---|
1302 | |
---|
1303 | /// \brief Constructor. |
---|
1304 | /// |
---|
1305 | /// Constructor. |
---|
1306 | /// |
---|
1307 | /// \param digraph the digraph the algorithm will run on. |
---|
1308 | /// \param visitor The visitor of the algorithm. |
---|
1309 | /// |
---|
1310 | DfsVisit(const Digraph& digraph, Visitor& visitor) |
---|
1311 | : _digraph(&digraph), _visitor(&visitor), |
---|
1312 | _reached(0), local_reached(false) {} |
---|
1313 | |
---|
1314 | /// \brief Destructor. |
---|
1315 | /// |
---|
1316 | /// Destructor. |
---|
1317 | ~DfsVisit() { |
---|
1318 | if(local_reached) delete _reached; |
---|
1319 | } |
---|
1320 | |
---|
1321 | /// \brief Sets the map indicating if a node is reached. |
---|
1322 | /// |
---|
1323 | /// Sets the map indicating if a node is reached. |
---|
1324 | /// If you don't use this function before calling \ref run(), |
---|
1325 | /// it will allocate one. The destuctor deallocates this |
---|
1326 | /// automatically allocated map, of course. |
---|
1327 | /// \return <tt> (*this) </tt> |
---|
1328 | DfsVisit &reachedMap(ReachedMap &m) { |
---|
1329 | if(local_reached) { |
---|
1330 | delete _reached; |
---|
1331 | local_reached=false; |
---|
1332 | } |
---|
1333 | _reached = &m; |
---|
1334 | return *this; |
---|
1335 | } |
---|
1336 | |
---|
1337 | public: |
---|
1338 | /// \name Execution control |
---|
1339 | /// The simplest way to execute the algorithm is to use |
---|
1340 | /// one of the member functions called \c run(...). |
---|
1341 | /// \n |
---|
1342 | /// If you need more control on the execution, |
---|
1343 | /// first you must call \ref init(), then you can adda source node |
---|
1344 | /// with \ref addSource(). |
---|
1345 | /// Finally \ref start() will perform the actual path |
---|
1346 | /// computation. |
---|
1347 | |
---|
1348 | /// @{ |
---|
1349 | /// \brief Initializes the internal data structures. |
---|
1350 | /// |
---|
1351 | /// Initializes the internal data structures. |
---|
1352 | /// |
---|
1353 | void init() { |
---|
1354 | create_maps(); |
---|
1355 | _stack.resize(countNodes(*_digraph)); |
---|
1356 | _stack_head = -1; |
---|
1357 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
---|
1358 | _reached->set(u, false); |
---|
1359 | } |
---|
1360 | } |
---|
1361 | |
---|
1362 | /// \brief Adds a new source node. |
---|
1363 | /// |
---|
1364 | /// Adds a new source node to the set of nodes to be processed. |
---|
1365 | void addSource(Node s) { |
---|
1366 | if(!(*_reached)[s]) { |
---|
1367 | _reached->set(s,true); |
---|
1368 | _visitor->start(s); |
---|
1369 | _visitor->reach(s); |
---|
1370 | Arc e; |
---|
1371 | _digraph->firstOut(e, s); |
---|
1372 | if (e != INVALID) { |
---|
1373 | _stack[++_stack_head] = e; |
---|
1374 | } else { |
---|
1375 | _visitor->leave(s); |
---|
1376 | } |
---|
1377 | } |
---|
1378 | } |
---|
1379 | |
---|
1380 | /// \brief Processes the next arc. |
---|
1381 | /// |
---|
1382 | /// Processes the next arc. |
---|
1383 | /// |
---|
1384 | /// \return The processed arc. |
---|
1385 | /// |
---|
1386 | /// \pre The stack must not be empty! |
---|
1387 | Arc processNextArc() { |
---|
1388 | Arc e = _stack[_stack_head]; |
---|
1389 | Node m = _digraph->target(e); |
---|
1390 | if(!(*_reached)[m]) { |
---|
1391 | _visitor->discover(e); |
---|
1392 | _visitor->reach(m); |
---|
1393 | _reached->set(m, true); |
---|
1394 | _digraph->firstOut(_stack[++_stack_head], m); |
---|
1395 | } else { |
---|
1396 | _visitor->examine(e); |
---|
1397 | m = _digraph->source(e); |
---|
1398 | _digraph->nextOut(_stack[_stack_head]); |
---|
1399 | } |
---|
1400 | while (_stack_head>=0 && _stack[_stack_head] == INVALID) { |
---|
1401 | _visitor->leave(m); |
---|
1402 | --_stack_head; |
---|
1403 | if (_stack_head >= 0) { |
---|
1404 | _visitor->backtrack(_stack[_stack_head]); |
---|
1405 | m = _digraph->source(_stack[_stack_head]); |
---|
1406 | _digraph->nextOut(_stack[_stack_head]); |
---|
1407 | } else { |
---|
1408 | _visitor->stop(m); |
---|
1409 | } |
---|
1410 | } |
---|
1411 | return e; |
---|
1412 | } |
---|
1413 | |
---|
1414 | /// \brief Next arc to be processed. |
---|
1415 | /// |
---|
1416 | /// Next arc to be processed. |
---|
1417 | /// |
---|
1418 | /// \return The next arc to be processed or INVALID if the stack is |
---|
1419 | /// empty. |
---|
1420 | Arc nextArc() { |
---|
1421 | return _stack_head >= 0 ? _stack[_stack_head] : INVALID; |
---|
1422 | } |
---|
1423 | |
---|
1424 | /// \brief Returns \c false if there are nodes |
---|
1425 | /// to be processed in the queue |
---|
1426 | /// |
---|
1427 | /// Returns \c false if there are nodes |
---|
1428 | /// to be processed in the queue |
---|
1429 | bool emptyQueue() { return _stack_head < 0; } |
---|
1430 | |
---|
1431 | /// \brief Returns the number of the nodes to be processed. |
---|
1432 | /// |
---|
1433 | /// Returns the number of the nodes to be processed in the queue. |
---|
1434 | int queueSize() { return _stack_head + 1; } |
---|
1435 | |
---|
1436 | /// \brief Executes the algorithm. |
---|
1437 | /// |
---|
1438 | /// Executes the algorithm. |
---|
1439 | /// |
---|
1440 | /// \pre init() must be called and at least one node should be added |
---|
1441 | /// with addSource() before using this function. |
---|
1442 | void start() { |
---|
1443 | while ( !emptyQueue() ) processNextArc(); |
---|
1444 | } |
---|
1445 | |
---|
1446 | /// \brief Executes the algorithm until \c dest is reached. |
---|
1447 | /// |
---|
1448 | /// Executes the algorithm until \c dest is reached. |
---|
1449 | /// |
---|
1450 | /// \pre init() must be called and at least one node should be added |
---|
1451 | /// with addSource() before using this function. |
---|
1452 | void start(Node dest) { |
---|
1453 | while ( !emptyQueue() && _digraph->target(_stack[_stack_head]) != dest ) |
---|
1454 | processNextArc(); |
---|
1455 | } |
---|
1456 | |
---|
1457 | /// \brief Executes the algorithm until a condition is met. |
---|
1458 | /// |
---|
1459 | /// Executes the algorithm until a condition is met. |
---|
1460 | /// |
---|
1461 | /// \pre init() must be called and at least one node should be added |
---|
1462 | /// with addSource() before using this function. |
---|
1463 | /// |
---|
1464 | /// \param em must be a bool (or convertible) arc map. The algorithm |
---|
1465 | /// will stop when it reaches an arc \c e with <tt>em[e]</tt> true. |
---|
1466 | /// |
---|
1467 | ///\return The reached arc \c e with <tt>em[e]</tt> true or |
---|
1468 | ///\c INVALID if no such arc was found. |
---|
1469 | /// |
---|
1470 | /// \warning Contrary to \ref Bfs and \ref Dijkstra, \c em is an arc map, |
---|
1471 | /// not a node map. |
---|
1472 | template <typename EM> |
---|
1473 | Arc start(const EM &em) { |
---|
1474 | while ( !emptyQueue() && !em[_stack[_stack_head]] ) |
---|
1475 | processNextArc(); |
---|
1476 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
1477 | } |
---|
1478 | |
---|
1479 | /// \brief Runs %DFSVisit algorithm from node \c s. |
---|
1480 | /// |
---|
1481 | /// This method runs the %DFS algorithm from a root node \c s. |
---|
1482 | /// \note d.run(s) is just a shortcut of the following code. |
---|
1483 | ///\code |
---|
1484 | /// d.init(); |
---|
1485 | /// d.addSource(s); |
---|
1486 | /// d.start(); |
---|
1487 | ///\endcode |
---|
1488 | void run(Node s) { |
---|
1489 | init(); |
---|
1490 | addSource(s); |
---|
1491 | start(); |
---|
1492 | } |
---|
1493 | |
---|
1494 | /// \brief Runs %DFSVisit algorithm to visit all nodes in the digraph. |
---|
1495 | |
---|
1496 | /// This method runs the %DFS algorithm in order to |
---|
1497 | /// compute the %DFS path to each node. The algorithm computes |
---|
1498 | /// - The %DFS tree. |
---|
1499 | /// - The distance of each node from the root in the %DFS tree. |
---|
1500 | /// |
---|
1501 | ///\note d.run() is just a shortcut of the following code. |
---|
1502 | ///\code |
---|
1503 | /// d.init(); |
---|
1504 | /// for (NodeIt it(digraph); it != INVALID; ++it) { |
---|
1505 | /// if (!d.reached(it)) { |
---|
1506 | /// d.addSource(it); |
---|
1507 | /// d.start(); |
---|
1508 | /// } |
---|
1509 | /// } |
---|
1510 | ///\endcode |
---|
1511 | void run() { |
---|
1512 | init(); |
---|
1513 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
1514 | if (!reached(it)) { |
---|
1515 | addSource(it); |
---|
1516 | start(); |
---|
1517 | } |
---|
1518 | } |
---|
1519 | } |
---|
1520 | ///@} |
---|
1521 | |
---|
1522 | /// \name Query Functions |
---|
1523 | /// The result of the %DFS algorithm can be obtained using these |
---|
1524 | /// functions.\n |
---|
1525 | /// Before the use of these functions, |
---|
1526 | /// either run() or start() must be called. |
---|
1527 | ///@{ |
---|
1528 | /// \brief Checks if a node is reachable from the root. |
---|
1529 | /// |
---|
1530 | /// Returns \c true if \c v is reachable from the root(s). |
---|
1531 | /// \warning The source nodes are inditated as unreachable. |
---|
1532 | /// \pre Either \ref run() or \ref start() |
---|
1533 | /// must be called before using this function. |
---|
1534 | /// |
---|
1535 | bool reached(Node v) { return (*_reached)[v]; } |
---|
1536 | ///@} |
---|
1537 | }; |
---|
1538 | |
---|
1539 | |
---|
1540 | } //END OF NAMESPACE LEMON |
---|
1541 | |
---|
1542 | #endif |
---|
1543 | |
---|