1 | // -*- c++ -*- |
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2 | #ifndef LEMON_BFS_DFS_H |
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3 | #define LEMON_BFS_DFS_H |
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4 | |
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5 | /// \ingroup galgs |
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6 | /// \file |
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7 | /// \brief Bfs and dfs iterators. |
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8 | /// |
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9 | /// This file contains bfs and dfs iterator classes. |
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10 | /// |
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11 | // /// \author Marton Makai |
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12 | |
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13 | #include <queue> |
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14 | #include <stack> |
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15 | #include <utility> |
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16 | |
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17 | #include <lemon/invalid.h> |
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18 | |
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19 | namespace lemon { |
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20 | |
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21 | /// Bfs searches for the nodes wich are not marked in |
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22 | /// \c reached_map |
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23 | /// Reached have to be a read-write bool node-map. |
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24 | /// \ingroup galgs |
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25 | template <typename Graph, /*typename OutEdgeIt,*/ |
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26 | typename ReachedMap/*=typename Graph::NodeMap<bool>*/ > |
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27 | class BfsIterator { |
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28 | protected: |
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29 | typedef typename Graph::Node Node; |
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30 | typedef typename Graph::Edge Edge; |
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31 | typedef typename Graph::OutEdgeIt OutEdgeIt; |
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32 | const Graph* graph; |
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33 | std::queue<Node> bfs_queue; |
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34 | ReachedMap& reached; |
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35 | bool b_node_newly_reached; |
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36 | Edge actual_edge; |
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37 | bool own_reached_map; |
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38 | public: |
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39 | /// In that constructor \c _reached have to be a reference |
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40 | /// for a bool bode-map. The algorithm will search for the |
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41 | /// initially \c false nodes |
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42 | /// in a bfs order. |
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43 | BfsIterator(const Graph& _graph, ReachedMap& _reached) : |
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44 | graph(&_graph), reached(_reached), |
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45 | own_reached_map(false) { } |
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46 | /// The same as above, but the map storing the reached nodes |
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47 | /// is constructed dynamically to everywhere false. |
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48 | /// \deprecated |
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49 | BfsIterator(const Graph& _graph) : |
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50 | graph(&_graph), reached(*(new ReachedMap(*graph /*, false*/))), |
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51 | own_reached_map(true) { } |
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52 | /// The map storing the reached nodes have to be destroyed if |
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53 | /// it was constructed dynamically |
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54 | ~BfsIterator() { if (own_reached_map) delete &reached; } |
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55 | /// This method markes \c s reached. |
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56 | /// If the queue is empty, then \c s is pushed in the bfs queue |
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57 | /// and the first out-edge is processed. |
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58 | /// If the queue is not empty, then \c s is simply pushed. |
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59 | BfsIterator<Graph, /*OutEdgeIt,*/ ReachedMap>& pushAndSetReached(Node s) { |
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60 | reached.set(s, true); |
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61 | if (bfs_queue.empty()) { |
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62 | bfs_queue.push(s); |
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63 | actual_edge=OutEdgeIt(*graph, s); |
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64 | //graph->first(actual_edge, s); |
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65 | if (actual_edge!=INVALID) { |
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66 | Node w=graph->head(actual_edge); |
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67 | if (!reached[w]) { |
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68 | bfs_queue.push(w); |
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69 | reached.set(w, true); |
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70 | b_node_newly_reached=true; |
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71 | } else { |
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72 | b_node_newly_reached=false; |
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73 | } |
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74 | } |
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75 | } else { |
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76 | bfs_queue.push(s); |
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77 | } |
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78 | return *this; |
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79 | } |
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80 | /// As \c BfsIterator<Graph, ReachedMap> works as an edge-iterator, |
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81 | /// its \c operator++() iterates on the edges in a bfs order. |
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82 | BfsIterator<Graph, /*OutEdgeIt,*/ ReachedMap>& |
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83 | operator++() { |
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84 | if (actual_edge!=INVALID) { |
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85 | actual_edge=++OutEdgeIt(*graph, actual_edge); |
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86 | //++actual_edge; |
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87 | if (actual_edge!=INVALID) { |
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88 | Node w=graph->head(actual_edge); |
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89 | if (!reached[w]) { |
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90 | bfs_queue.push(w); |
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91 | reached.set(w, true); |
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92 | b_node_newly_reached=true; |
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93 | } else { |
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94 | b_node_newly_reached=false; |
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95 | } |
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96 | } |
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97 | } else { |
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98 | bfs_queue.pop(); |
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99 | if (!bfs_queue.empty()) { |
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100 | actual_edge=OutEdgeIt(*graph, bfs_queue.front()); |
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101 | //graph->first(actual_edge, bfs_queue.front()); |
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102 | if (actual_edge!=INVALID) { |
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103 | Node w=graph->head(actual_edge); |
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104 | if (!reached[w]) { |
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105 | bfs_queue.push(w); |
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106 | reached.set(w, true); |
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107 | b_node_newly_reached=true; |
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108 | } else { |
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109 | b_node_newly_reached=false; |
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110 | } |
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111 | } |
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112 | } |
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113 | } |
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114 | return *this; |
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115 | } |
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116 | /// Returns true iff the algorithm is finished. |
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117 | bool finished() const { return bfs_queue.empty(); } |
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118 | /// The conversion operator makes for converting the bfs-iterator |
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119 | /// to an \c out-edge-iterator. |
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120 | ///\bug Edge have to be in LEMON 0.2 |
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121 | operator Edge() const { return actual_edge; } |
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122 | /// Returns if b-node has been reached just now. |
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123 | bool isBNodeNewlyReached() const { return b_node_newly_reached; } |
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124 | /// Returns if a-node is examined. |
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125 | bool isANodeExamined() const { return actual_edge==INVALID; } |
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126 | /// Returns a-node of the actual edge, so does if the edge is invalid. |
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127 | Node tail() const { return bfs_queue.front(); } |
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128 | /// \pre The actual edge have to be valid. |
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129 | Node head() const { return graph->head(actual_edge); } |
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130 | /// Guess what? |
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131 | /// \deprecated |
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132 | const ReachedMap& getReachedMap() const { return reached; } |
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133 | /// Guess what? |
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134 | /// \deprecated |
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135 | const std::queue<Node>& getBfsQueue() const { return bfs_queue; } |
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136 | }; |
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137 | |
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138 | /// Bfs searches for the nodes wich are not marked in |
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139 | /// \c reached_map |
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140 | /// Reached have to work as a read-write bool Node-map, |
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141 | /// Pred is a write edge node-map and |
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142 | /// Dist is a read-write node-map of integral value, have to be. |
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143 | /// \ingroup galgs |
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144 | template <typename Graph, |
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145 | typename ReachedMap=typename Graph::template NodeMap<bool>, |
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146 | typename PredMap |
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147 | =typename Graph::template NodeMap<typename Graph::Edge>, |
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148 | typename DistMap=typename Graph::template NodeMap<int> > |
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149 | class Bfs : public BfsIterator<Graph, ReachedMap> { |
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150 | typedef BfsIterator<Graph, ReachedMap> Parent; |
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151 | protected: |
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152 | typedef typename Parent::Node Node; |
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153 | PredMap& pred; |
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154 | DistMap& dist; |
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155 | public: |
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156 | /// The algorithm will search in a bfs order for |
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157 | /// the nodes which are \c false initially. |
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158 | /// The constructor makes no initial changes on the maps. |
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159 | Bfs<Graph, ReachedMap, PredMap, DistMap>(const Graph& _graph, ReachedMap& _reached, PredMap& _pred, DistMap& _dist) : |
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160 | BfsIterator<Graph, ReachedMap>(_graph, _reached), |
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161 | pred(_pred), dist(_dist) { } |
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162 | /// \c s is marked to be reached and pushed in the bfs queue. |
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163 | /// If the queue is empty, then the first out-edge is processed. |
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164 | /// If \c s was not marked previously, then |
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165 | /// in addition its pred is set to be \c INVALID, and dist to \c 0. |
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166 | /// if \c s was marked previuosly, then it is simply pushed. |
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167 | Bfs<Graph, ReachedMap, PredMap, DistMap>& push(Node s) { |
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168 | if (this->reached[s]) { |
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169 | Parent::pushAndSetReached(s); |
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170 | } else { |
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171 | Parent::pushAndSetReached(s); |
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172 | pred.set(s, INVALID); |
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173 | dist.set(s, 0); |
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174 | } |
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175 | return *this; |
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176 | } |
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177 | /// A bfs is processed from \c s. |
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178 | Bfs<Graph, ReachedMap, PredMap, DistMap>& run(Node s) { |
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179 | push(s); |
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180 | while (!this->finished()) this->operator++(); |
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181 | return *this; |
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182 | } |
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183 | /// Beside the bfs iteration, \c pred and \dist are saved in a |
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184 | /// newly reached node. |
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185 | Bfs<Graph, ReachedMap, PredMap, DistMap>& operator++() { |
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186 | Parent::operator++(); |
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187 | if (this->graph->valid(this->actual_edge) && this->b_node_newly_reached) |
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188 | { |
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189 | pred.set(this->head(), this->actual_edge); |
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190 | dist.set(this->head(), dist[this->tail()]); |
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191 | } |
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192 | return *this; |
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193 | } |
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194 | /// Guess what? |
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195 | /// \deprecated |
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196 | const PredMap& getPredMap() const { return pred; } |
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197 | /// Guess what? |
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198 | /// \deprecated |
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199 | const DistMap& getDistMap() const { return dist; } |
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200 | }; |
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201 | |
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202 | /// Dfs searches for the nodes wich are not marked in |
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203 | /// \c reached_map |
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204 | /// Reached have to be a read-write bool Node-map. |
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205 | /// \ingroup galgs |
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206 | template <typename Graph, /*typename OutEdgeIt,*/ |
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207 | typename ReachedMap/*=typename Graph::NodeMap<bool>*/ > |
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208 | class DfsIterator { |
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209 | protected: |
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210 | typedef typename Graph::Node Node; |
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211 | typedef typename Graph::Edge Edge; |
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212 | typedef typename Graph::OutEdgeIt OutEdgeIt; |
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213 | const Graph* graph; |
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214 | std::stack<OutEdgeIt> dfs_stack; |
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215 | bool b_node_newly_reached; |
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216 | Edge actual_edge; |
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217 | Node actual_node; |
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218 | ReachedMap& reached; |
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219 | bool own_reached_map; |
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220 | public: |
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221 | /// In that constructor \c _reached have to be a reference |
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222 | /// for a bool node-map. The algorithm will search in a dfs order for |
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223 | /// the nodes which are \c false initially |
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224 | DfsIterator(const Graph& _graph, ReachedMap& _reached) : |
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225 | graph(&_graph), reached(_reached), |
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226 | own_reached_map(false) { } |
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227 | /// The same as above, but the map of reached nodes is |
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228 | /// constructed dynamically |
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229 | /// to everywhere false. |
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230 | DfsIterator(const Graph& _graph) : |
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231 | graph(&_graph), reached(*(new ReachedMap(*graph /*, false*/))), |
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232 | own_reached_map(true) { } |
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233 | ~DfsIterator() { if (own_reached_map) delete &reached; } |
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234 | /// This method markes s reached and first out-edge is processed. |
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235 | DfsIterator<Graph, /*OutEdgeIt,*/ ReachedMap>& pushAndSetReached(Node s) { |
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236 | actual_node=s; |
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237 | reached.set(s, true); |
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238 | OutEdgeIt e(*graph, s); |
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239 | //graph->first(e, s); |
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240 | dfs_stack.push(e); |
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241 | return *this; |
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242 | } |
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243 | /// As \c DfsIterator<Graph, ReachedMap> works as an edge-iterator, |
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244 | /// its \c operator++() iterates on the edges in a dfs order. |
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245 | DfsIterator<Graph, /*OutEdgeIt,*/ ReachedMap>& |
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246 | operator++() { |
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247 | actual_edge=dfs_stack.top(); |
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248 | if (actual_edge!=INVALID/*.valid()*/) { |
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249 | Node w=graph->head(actual_edge); |
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250 | actual_node=w; |
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251 | if (!reached[w]) { |
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252 | OutEdgeIt e(*graph, w); |
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253 | //graph->first(e, w); |
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254 | dfs_stack.push(e); |
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255 | reached.set(w, true); |
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256 | b_node_newly_reached=true; |
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257 | } else { |
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258 | actual_node=graph->tail(actual_edge); |
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259 | ++dfs_stack.top(); |
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260 | b_node_newly_reached=false; |
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261 | } |
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262 | } else { |
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263 | //actual_node=G.aNode(dfs_stack.top()); |
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264 | dfs_stack.pop(); |
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265 | } |
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266 | return *this; |
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267 | } |
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268 | /// Returns true iff the algorithm is finished. |
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269 | bool finished() const { return dfs_stack.empty(); } |
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270 | /// The conversion operator makes for converting the bfs-iterator |
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271 | /// to an \c out-edge-iterator. |
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272 | ///\bug Edge have to be in LEMON 0.2 |
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273 | operator Edge() const { return actual_edge; } |
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274 | /// Returns if b-node has been reached just now. |
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275 | bool isBNodeNewlyReached() const { return b_node_newly_reached; } |
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276 | /// Returns if a-node is examined. |
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277 | bool isANodeExamined() const { return actual_edge==INVALID; } |
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278 | /// Returns a-node of the actual edge, so does if the edge is invalid. |
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279 | Node tail() const { return actual_node; /*FIXME*/} |
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280 | /// Returns b-node of the actual edge. |
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281 | /// \pre The actual edge have to be valid. |
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282 | Node head() const { return graph->head(actual_edge); } |
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283 | /// Guess what? |
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284 | /// \deprecated |
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285 | const ReachedMap& getReachedMap() const { return reached; } |
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286 | /// Guess what? |
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287 | /// \deprecated |
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288 | const std::stack<OutEdgeIt>& getDfsStack() const { return dfs_stack; } |
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289 | }; |
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290 | |
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291 | /// Dfs searches for the nodes wich are not marked in |
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292 | /// \c reached_map |
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293 | /// Reached is a read-write bool node-map, |
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294 | /// Pred is a write node-map, have to be. |
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295 | /// \ingroup galgs |
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296 | template <typename Graph, |
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297 | typename ReachedMap=typename Graph::template NodeMap<bool>, |
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298 | typename PredMap |
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299 | =typename Graph::template NodeMap<typename Graph::Edge> > |
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300 | class Dfs : public DfsIterator<Graph, ReachedMap> { |
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301 | typedef DfsIterator<Graph, ReachedMap> Parent; |
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302 | protected: |
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303 | typedef typename Parent::Node Node; |
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304 | PredMap& pred; |
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305 | public: |
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306 | /// The algorithm will search in a dfs order for |
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307 | /// the nodes which are \c false initially. |
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308 | /// The constructor makes no initial changes on the maps. |
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309 | Dfs<Graph, ReachedMap, PredMap>(const Graph& _graph, ReachedMap& _reached, PredMap& _pred) : DfsIterator<Graph, ReachedMap>(_graph, _reached), pred(_pred) { } |
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310 | /// \c s is marked to be reached and pushed in the bfs queue. |
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311 | /// If the queue is empty, then the first out-edge is processed. |
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312 | /// If \c s was not marked previously, then |
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313 | /// in addition its pred is set to be \c INVALID. |
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314 | /// if \c s was marked previuosly, then it is simply pushed. |
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315 | Dfs<Graph, ReachedMap, PredMap>& push(Node s) { |
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316 | if (this->reached[s]) { |
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317 | Parent::pushAndSetReached(s); |
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318 | } else { |
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319 | Parent::pushAndSetReached(s); |
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320 | pred.set(s, INVALID); |
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321 | } |
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322 | return *this; |
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323 | } |
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324 | /// A bfs is processed from \c s. |
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325 | Dfs<Graph, ReachedMap, PredMap>& run(Node s) { |
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326 | push(s); |
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327 | while (!this->finished()) this->operator++(); |
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328 | return *this; |
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329 | } |
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330 | /// Beside the dfs iteration, \c pred is saved in a |
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331 | /// newly reached node. |
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332 | Dfs<Graph, ReachedMap, PredMap>& operator++() { |
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333 | Parent::operator++(); |
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334 | if (this->graph->valid(this->actual_edge) && this->b_node_newly_reached) |
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335 | { |
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336 | pred.set(this->head(), this->actual_edge); |
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337 | } |
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338 | return *this; |
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339 | } |
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340 | /// Guess what? |
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341 | /// \deprecated |
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342 | const PredMap& getPredMap() const { return pred; } |
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343 | }; |
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344 | |
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345 | |
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346 | } // namespace lemon |
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347 | |
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348 | #endif //LEMON_BFS_DFS_H |
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