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1 // -*- C++ -*- |
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2 #ifndef HUGO_AUGMENTING_FLOW_H |
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3 #define HUGO_AUGMENTING_FLOW_H |
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4 |
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5 #include <vector> |
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6 #include <queue> |
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7 #include <stack> |
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8 #include <iostream> |
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9 |
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10 #include <hugo/graph_wrapper.h> |
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11 #include <bfs_dfs.h> |
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12 #include <hugo/invalid.h> |
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13 #include <hugo/maps.h> |
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14 #include <for_each_macros.h> |
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15 |
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16 /// \file |
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17 /// \brief Maximum flow algorithms. |
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18 /// \ingroup galgs |
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19 |
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20 namespace hugo { |
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21 |
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22 /// \addtogroup galgs |
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23 /// @{ |
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24 ///Maximum flow algorithms class. |
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25 |
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26 ///This class provides various algorithms for finding a flow of |
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27 ///maximum value in a directed graph. The \e source node, the \e |
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28 ///target node, the \e capacity of the edges and the \e starting \e |
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29 ///flow value of the edges should be passed to the algorithm through the |
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30 ///constructor. It is possible to change these quantities using the |
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31 ///functions \ref resetSource, \ref resetTarget, \ref resetCap and |
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32 ///\ref resetFlow. Before any subsequent runs of any algorithm of |
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33 ///the class \ref resetFlow should be called. |
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34 |
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35 ///After running an algorithm of the class, the actual flow value |
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36 ///can be obtained by calling \ref flowValue(). The minimum |
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37 ///value cut can be written into a \c node map of \c bools by |
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38 ///calling \ref minCut. (\ref minMinCut and \ref maxMinCut writes |
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39 ///the inclusionwise minimum and maximum of the minimum value |
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40 ///cuts, resp.) |
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41 ///\param Graph The directed graph type the algorithm runs on. |
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42 ///\param Num The number type of the capacities and the flow values. |
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43 ///\param CapMap The capacity map type. |
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44 ///\param FlowMap The flow map type. |
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45 ///\author Marton Makai, Jacint Szabo |
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46 // template <typename Graph, typename Num, |
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47 // typename CapMap=typename Graph::template EdgeMap<Num>, |
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48 // typename FlowMap=typename Graph::template EdgeMap<Num> > |
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49 // class MaxFlow { |
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50 // protected: |
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51 // typedef typename Graph::Node Node; |
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52 // typedef typename Graph::NodeIt NodeIt; |
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53 // typedef typename Graph::EdgeIt EdgeIt; |
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54 // typedef typename Graph::OutEdgeIt OutEdgeIt; |
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55 // typedef typename Graph::InEdgeIt InEdgeIt; |
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56 |
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57 // typedef typename std::vector<std::stack<Node> > VecStack; |
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58 // typedef typename Graph::template NodeMap<Node> NNMap; |
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59 // typedef typename std::vector<Node> VecNode; |
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60 |
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61 // const Graph* g; |
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62 // Node s; |
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63 // Node t; |
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64 // const CapMap* capacity; |
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65 // FlowMap* flow; |
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66 // int n; //the number of nodes of G |
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67 // typedef ResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW; |
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68 // //typedef ExpResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW; |
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69 // typedef typename ResGW::OutEdgeIt ResGWOutEdgeIt; |
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70 // typedef typename ResGW::Edge ResGWEdge; |
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71 // //typedef typename ResGW::template NodeMap<bool> ReachedMap; |
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72 // typedef typename Graph::template NodeMap<int> ReachedMap; |
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73 |
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74 |
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75 // //level works as a bool map in augmenting path algorithms and is |
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76 // //used by bfs for storing reached information. In preflow, it |
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77 // //shows the levels of nodes. |
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78 // ReachedMap level; |
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79 |
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80 // //excess is needed only in preflow |
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81 // typename Graph::template NodeMap<Num> excess; |
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82 |
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83 // //fixme |
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84 // // protected: |
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85 // // MaxFlow() { } |
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86 // // void set(const Graph& _G, Node _s, Node _t, const CapMap& _capacity, |
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87 // // FlowMap& _flow) |
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88 // // { |
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89 // // g=&_G; |
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90 // // s=_s; |
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91 // // t=_t; |
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92 // // capacity=&_capacity; |
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93 // // flow=&_flow; |
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94 // // n=_G.nodeNum; |
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95 // // level.set (_G); //kellene vmi ilyesmi fv |
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96 // // excess(_G,0); //itt is |
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97 // // } |
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98 |
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99 // // constants used for heuristics |
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100 // static const int H0=20; |
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101 // static const int H1=1; |
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102 |
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103 // public: |
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104 |
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105 // ///Indicates the property of the starting flow. |
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106 |
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107 // ///Indicates the property of the starting flow. The meanings are as follows: |
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108 // ///- \c ZERO_FLOW: constant zero flow |
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109 // ///- \c GEN_FLOW: any flow, i.e. the sum of the in-flows equals to |
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110 // ///the sum of the out-flows in every node except the \e source and |
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111 // ///the \e target. |
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112 // ///- \c PRE_FLOW: any preflow, i.e. the sum of the in-flows is at |
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113 // ///least the sum of the out-flows in every node except the \e source. |
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114 // ///- \c NO_FLOW: indicates an unspecified edge map. \ref flow will be |
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115 // ///set to the constant zero flow in the beginning of the algorithm in this case. |
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116 // enum FlowEnum{ |
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117 // ZERO_FLOW, |
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118 // GEN_FLOW, |
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119 // PRE_FLOW, |
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120 // NO_FLOW |
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121 // }; |
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122 |
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123 // enum StatusEnum { |
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124 // AFTER_NOTHING, |
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125 // AFTER_AUGMENTING, |
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126 // AFTER_FAST_AUGMENTING, |
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127 // AFTER_PRE_FLOW_PHASE_1, |
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128 // AFTER_PRE_FLOW_PHASE_2 |
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129 // }; |
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130 |
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131 // /// Don not needle this flag only if necessary. |
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132 // StatusEnum status; |
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133 // // int number_of_augmentations; |
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134 |
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135 |
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136 // // template<typename IntMap> |
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137 // // class TrickyReachedMap { |
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138 // // protected: |
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139 // // IntMap* map; |
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140 // // int* number_of_augmentations; |
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141 // // public: |
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142 // // TrickyReachedMap(IntMap& _map, int& _number_of_augmentations) : |
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143 // // map(&_map), number_of_augmentations(&_number_of_augmentations) { } |
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144 // // void set(const Node& n, bool b) { |
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145 // // if (b) |
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146 // // map->set(n, *number_of_augmentations); |
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147 // // else |
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148 // // map->set(n, *number_of_augmentations-1); |
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149 // // } |
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150 // // bool operator[](const Node& n) const { |
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151 // // return (*map)[n]==*number_of_augmentations; |
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152 // // } |
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153 // // }; |
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154 |
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155 // MaxFlow(const Graph& _G, Node _s, Node _t, const CapMap& _capacity, |
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156 // FlowMap& _flow) : |
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157 // g(&_G), s(_s), t(_t), capacity(&_capacity), |
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158 // flow(&_flow), n(_G.nodeNum()), level(_G), excess(_G,0), |
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159 // status(AFTER_NOTHING) { } |
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160 |
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161 // ///Runs a maximum flow algorithm. |
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162 |
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163 // ///Runs a preflow algorithm, which is the fastest maximum flow |
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164 // ///algorithm up-to-date. The default for \c fe is ZERO_FLOW. |
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165 // ///\pre The starting flow must be |
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166 // /// - a constant zero flow if \c fe is \c ZERO_FLOW, |
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167 // /// - an arbitary flow if \c fe is \c GEN_FLOW, |
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168 // /// - an arbitary preflow if \c fe is \c PRE_FLOW, |
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169 // /// - any map if \c fe is NO_FLOW. |
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170 // void run(FlowEnum fe=ZERO_FLOW) { |
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171 // preflow(fe); |
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172 // } |
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173 |
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174 |
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175 // ///Runs a preflow algorithm. |
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176 |
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177 // ///Runs a preflow algorithm. The preflow algorithms provide the |
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178 // ///fastest way to compute a maximum flow in a directed graph. |
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179 // ///\pre The starting flow must be |
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180 // /// - a constant zero flow if \c fe is \c ZERO_FLOW, |
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181 // /// - an arbitary flow if \c fe is \c GEN_FLOW, |
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182 // /// - an arbitary preflow if \c fe is \c PRE_FLOW, |
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183 // /// - any map if \c fe is NO_FLOW. |
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184 // void preflow(FlowEnum fe) { |
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185 // preflowPhase1(fe); |
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186 // preflowPhase2(); |
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187 // } |
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188 // // Heuristics: |
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189 // // 2 phase |
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190 // // gap |
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191 // // list 'level_list' on the nodes on level i implemented by hand |
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192 // // stack 'active' on the active nodes on level i |
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193 // // runs heuristic 'highest label' for H1*n relabels |
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194 // // runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label' |
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195 // // Parameters H0 and H1 are initialized to 20 and 1. |
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196 |
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197 // ///Runs the first phase of the preflow algorithm. |
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198 |
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199 // ///The preflow algorithm consists of two phases, this method runs the |
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200 // ///first phase. After the first phase the maximum flow value and a |
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201 // ///minimum value cut can already be computed, though a maximum flow |
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202 // ///is net yet obtained. So after calling this method \ref flowValue |
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203 // ///and \ref actMinCut gives proper results. |
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204 // ///\warning: \ref minCut, \ref minMinCut and \ref maxMinCut do not |
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205 // ///give minimum value cuts unless calling \ref preflowPhase2. |
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206 // ///\pre The starting flow must be |
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207 // /// - a constant zero flow if \c fe is \c ZERO_FLOW, |
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208 // /// - an arbitary flow if \c fe is \c GEN_FLOW, |
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209 // /// - an arbitary preflow if \c fe is \c PRE_FLOW, |
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210 // /// - any map if \c fe is NO_FLOW. |
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211 // void preflowPhase1(FlowEnum fe); |
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212 |
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213 // ///Runs the second phase of the preflow algorithm. |
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214 |
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215 // ///The preflow algorithm consists of two phases, this method runs |
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216 // ///the second phase. After calling \ref preflowPhase1 and then |
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217 // ///\ref preflowPhase2 the methods \ref flowValue, \ref minCut, |
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218 // ///\ref minMinCut and \ref maxMinCut give proper results. |
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219 // ///\pre \ref preflowPhase1 must be called before. |
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220 // void preflowPhase2(); |
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221 |
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222 // /// Returns the maximum value of a flow. |
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223 |
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224 // /// Returns the maximum value of a flow, by counting the |
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225 // /// over-flow of the target node \ref t. |
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226 // /// It can be called already after running \ref preflowPhase1. |
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227 // Num flowValue() const { |
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228 // Num a=0; |
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229 // FOR_EACH_INC_LOC(InEdgeIt, e, *g, t) a+=(*flow)[e]; |
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230 // FOR_EACH_INC_LOC(OutEdgeIt, e, *g, t) a-=(*flow)[e]; |
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231 // return a; |
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232 // //marci figyu: excess[t] epp ezt adja preflow 1. fazisa utan |
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233 // } |
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234 |
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235 // ///Returns a minimum value cut after calling \ref preflowPhase1. |
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236 |
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237 // ///After the first phase of the preflow algorithm the maximum flow |
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238 // ///value and a minimum value cut can already be computed. This |
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239 // ///method can be called after running \ref preflowPhase1 for |
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240 // ///obtaining a minimum value cut. |
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241 // /// \warning Gives proper result only right after calling \ref |
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242 // /// preflowPhase1. |
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243 // /// \todo We have to make some status variable which shows the |
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244 // /// actual state |
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245 // /// of the class. This enables us to determine which methods are valid |
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246 // /// for MinCut computation |
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247 // template<typename _CutMap> |
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248 // void actMinCut(_CutMap& M) const { |
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249 // NodeIt v; |
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250 // switch (status) { |
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251 // case AFTER_PRE_FLOW_PHASE_1: |
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252 // for(g->first(v); g->valid(v); g->next(v)) { |
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253 // if (level[v] < n) { |
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254 // M.set(v, false); |
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255 // } else { |
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256 // M.set(v, true); |
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257 // } |
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258 // } |
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259 // break; |
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260 // case AFTER_PRE_FLOW_PHASE_2: |
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261 // case AFTER_NOTHING: |
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262 // case AFTER_AUGMENTING: |
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263 // case AFTER_FAST_AUGMENTING: |
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264 // minMinCut(M); |
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265 // break; |
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266 // // case AFTER_AUGMENTING: |
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267 // // for(g->first(v); g->valid(v); g->next(v)) { |
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268 // // if (level[v]) { |
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269 // // M.set(v, true); |
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270 // // } else { |
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271 // // M.set(v, false); |
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272 // // } |
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273 // // } |
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274 // // break; |
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275 // // case AFTER_FAST_AUGMENTING: |
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276 // // for(g->first(v); g->valid(v); g->next(v)) { |
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277 // // if (level[v]==number_of_augmentations) { |
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278 // // M.set(v, true); |
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279 // // } else { |
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280 // // M.set(v, false); |
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281 // // } |
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282 // // } |
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283 // // break; |
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284 // } |
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285 // } |
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286 |
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287 // ///Returns the inclusionwise minimum of the minimum value cuts. |
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288 |
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289 // ///Sets \c M to the characteristic vector of the minimum value cut |
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290 // ///which is inclusionwise minimum. It is computed by processing |
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291 // ///a bfs from the source node \c s in the residual graph. |
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292 // ///\pre M should be a node map of bools initialized to false. |
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293 // ///\pre \c flow must be a maximum flow. |
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294 // template<typename _CutMap> |
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295 // void minMinCut(_CutMap& M) const { |
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296 // std::queue<Node> queue; |
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297 |
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298 // M.set(s,true); |
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299 // queue.push(s); |
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300 |
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301 // while (!queue.empty()) { |
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302 // Node w=queue.front(); |
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303 // queue.pop(); |
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304 |
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305 // OutEdgeIt e; |
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306 // for(g->first(e,w) ; g->valid(e); g->next(e)) { |
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307 // Node v=g->head(e); |
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308 // if (!M[v] && (*flow)[e] < (*capacity)[e] ) { |
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309 // queue.push(v); |
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310 // M.set(v, true); |
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311 // } |
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312 // } |
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313 |
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314 // InEdgeIt f; |
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315 // for(g->first(f,w) ; g->valid(f); g->next(f)) { |
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316 // Node v=g->tail(f); |
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317 // if (!M[v] && (*flow)[f] > 0 ) { |
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318 // queue.push(v); |
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319 // M.set(v, true); |
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320 // } |
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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 // ///Returns the inclusionwise maximum of the minimum value cuts. |
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326 |
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327 // ///Sets \c M to the characteristic vector of the minimum value cut |
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328 // ///which is inclusionwise maximum. It is computed by processing a |
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329 // ///backward bfs from the target node \c t in the residual graph. |
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330 // ///\pre M should be a node map of bools initialized to false. |
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331 // ///\pre \c flow must be a maximum flow. |
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332 // template<typename _CutMap> |
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333 // void maxMinCut(_CutMap& M) const { |
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334 |
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335 // NodeIt v; |
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336 // for(g->first(v) ; g->valid(v); g->next(v)) { |
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337 // M.set(v, true); |
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338 // } |
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339 |
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340 // std::queue<Node> queue; |
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341 |
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342 // M.set(t,false); |
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343 // queue.push(t); |
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344 |
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345 // while (!queue.empty()) { |
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346 // Node w=queue.front(); |
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347 // queue.pop(); |
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348 |
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349 // InEdgeIt e; |
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350 // for(g->first(e,w) ; g->valid(e); g->next(e)) { |
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351 // Node v=g->tail(e); |
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352 // if (M[v] && (*flow)[e] < (*capacity)[e] ) { |
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353 // queue.push(v); |
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354 // M.set(v, false); |
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355 // } |
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356 // } |
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357 |
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358 // OutEdgeIt f; |
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359 // for(g->first(f,w) ; g->valid(f); g->next(f)) { |
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360 // Node v=g->head(f); |
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361 // if (M[v] && (*flow)[f] > 0 ) { |
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362 // queue.push(v); |
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363 // M.set(v, false); |
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364 // } |
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365 // } |
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366 // } |
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367 // } |
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368 |
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369 // ///Returns a minimum value cut. |
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370 |
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371 // ///Sets \c M to the characteristic vector of a minimum value cut. |
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372 // ///\pre M should be a node map of bools initialized to false. |
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373 // ///\pre \c flow must be a maximum flow. |
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374 // template<typename CutMap> |
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375 // void minCut(CutMap& M) const { minMinCut(M); } |
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376 |
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377 // ///Resets the source node to \c _s. |
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378 |
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379 // ///Resets the source node to \c _s. |
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380 // /// |
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381 // void resetSource(Node _s) { s=_s; status=AFTER_NOTHING; } |
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382 |
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383 // ///Resets the target node to \c _t. |
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384 |
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385 // ///Resets the target node to \c _t. |
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386 // /// |
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387 // void resetTarget(Node _t) { t=_t; status=AFTER_NOTHING; } |
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388 |
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389 // /// Resets the edge map of the capacities to _cap. |
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390 |
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391 // /// Resets the edge map of the capacities to _cap. |
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392 // /// |
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393 // void resetCap(const CapMap& _cap) { capacity=&_cap; status=AFTER_NOTHING; } |
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394 |
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395 // /// Resets the edge map of the flows to _flow. |
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396 |
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397 // /// Resets the edge map of the flows to _flow. |
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398 // /// |
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399 // void resetFlow(FlowMap& _flow) { flow=&_flow; status=AFTER_NOTHING; } |
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400 |
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401 |
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402 // private: |
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403 |
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404 // int push(Node w, VecStack& active) { |
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405 |
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406 // int lev=level[w]; |
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407 // Num exc=excess[w]; |
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408 // int newlevel=n; //bound on the next level of w |
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409 |
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410 // OutEdgeIt e; |
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411 // for(g->first(e,w); g->valid(e); g->next(e)) { |
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412 |
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413 // if ( (*flow)[e] >= (*capacity)[e] ) continue; |
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414 // Node v=g->head(e); |
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415 |
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416 // if( lev > level[v] ) { //Push is allowed now |
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417 |
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418 // if ( excess[v]<=0 && v!=t && v!=s ) { |
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419 // int lev_v=level[v]; |
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420 // active[lev_v].push(v); |
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421 // } |
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422 |
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423 // Num cap=(*capacity)[e]; |
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424 // Num flo=(*flow)[e]; |
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425 // Num remcap=cap-flo; |
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426 |
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427 // if ( remcap >= exc ) { //A nonsaturating push. |
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428 |
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429 // flow->set(e, flo+exc); |
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430 // excess.set(v, excess[v]+exc); |
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431 // exc=0; |
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432 // break; |
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433 |
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434 // } else { //A saturating push. |
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435 // flow->set(e, cap); |
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436 // excess.set(v, excess[v]+remcap); |
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437 // exc-=remcap; |
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438 // } |
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439 // } else if ( newlevel > level[v] ) newlevel = level[v]; |
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440 // } //for out edges wv |
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441 |
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442 // if ( exc > 0 ) { |
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443 // InEdgeIt e; |
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444 // for(g->first(e,w); g->valid(e); g->next(e)) { |
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445 |
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446 // if( (*flow)[e] <= 0 ) continue; |
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447 // Node v=g->tail(e); |
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448 |
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449 // if( lev > level[v] ) { //Push is allowed now |
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450 |
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451 // if ( excess[v]<=0 && v!=t && v!=s ) { |
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452 // int lev_v=level[v]; |
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453 // active[lev_v].push(v); |
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454 // } |
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455 |
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456 // Num flo=(*flow)[e]; |
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457 |
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458 // if ( flo >= exc ) { //A nonsaturating push. |
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459 |
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460 // flow->set(e, flo-exc); |
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461 // excess.set(v, excess[v]+exc); |
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462 // exc=0; |
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463 // break; |
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464 // } else { //A saturating push. |
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465 |
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466 // excess.set(v, excess[v]+flo); |
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467 // exc-=flo; |
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468 // flow->set(e,0); |
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469 // } |
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470 // } else if ( newlevel > level[v] ) newlevel = level[v]; |
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471 // } //for in edges vw |
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472 |
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473 // } // if w still has excess after the out edge for cycle |
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474 |
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475 // excess.set(w, exc); |
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476 |
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477 // return newlevel; |
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478 // } |
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479 |
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480 |
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481 // void preflowPreproc(FlowEnum fe, VecStack& active, |
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482 // VecNode& level_list, NNMap& left, NNMap& right) |
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483 // { |
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484 // std::queue<Node> bfs_queue; |
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485 |
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486 // switch (fe) { |
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487 // case NO_FLOW: //flow is already set to const zero in this case |
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488 // case ZERO_FLOW: |
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489 // { |
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490 // //Reverse_bfs from t, to find the starting level. |
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491 // level.set(t,0); |
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492 // bfs_queue.push(t); |
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493 |
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494 // while (!bfs_queue.empty()) { |
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495 |
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496 // Node v=bfs_queue.front(); |
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497 // bfs_queue.pop(); |
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498 // int l=level[v]+1; |
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499 |
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500 // InEdgeIt e; |
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501 // for(g->first(e,v); g->valid(e); g->next(e)) { |
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502 // Node w=g->tail(e); |
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503 // if ( level[w] == n && w != s ) { |
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504 // bfs_queue.push(w); |
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505 // Node first=level_list[l]; |
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506 // if ( g->valid(first) ) left.set(first,w); |
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507 // right.set(w,first); |
|
508 // level_list[l]=w; |
|
509 // level.set(w, l); |
|
510 // } |
|
511 // } |
|
512 // } |
|
513 |
|
514 // //the starting flow |
|
515 // OutEdgeIt e; |
|
516 // for(g->first(e,s); g->valid(e); g->next(e)) |
|
517 // { |
|
518 // Num c=(*capacity)[e]; |
|
519 // if ( c <= 0 ) continue; |
|
520 // Node w=g->head(e); |
|
521 // if ( level[w] < n ) { |
|
522 // if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w); |
|
523 // flow->set(e, c); |
|
524 // excess.set(w, excess[w]+c); |
|
525 // } |
|
526 // } |
|
527 // break; |
|
528 // } |
|
529 |
|
530 // case GEN_FLOW: |
|
531 // case PRE_FLOW: |
|
532 // { |
|
533 // //Reverse_bfs from t in the residual graph, |
|
534 // //to find the starting level. |
|
535 // level.set(t,0); |
|
536 // bfs_queue.push(t); |
|
537 |
|
538 // while (!bfs_queue.empty()) { |
|
539 |
|
540 // Node v=bfs_queue.front(); |
|
541 // bfs_queue.pop(); |
|
542 // int l=level[v]+1; |
|
543 |
|
544 // InEdgeIt e; |
|
545 // for(g->first(e,v); g->valid(e); g->next(e)) { |
|
546 // if ( (*capacity)[e] <= (*flow)[e] ) continue; |
|
547 // Node w=g->tail(e); |
|
548 // if ( level[w] == n && w != s ) { |
|
549 // bfs_queue.push(w); |
|
550 // Node first=level_list[l]; |
|
551 // if ( g->valid(first) ) left.set(first,w); |
|
552 // right.set(w,first); |
|
553 // level_list[l]=w; |
|
554 // level.set(w, l); |
|
555 // } |
|
556 // } |
|
557 |
|
558 // OutEdgeIt f; |
|
559 // for(g->first(f,v); g->valid(f); g->next(f)) { |
|
560 // if ( 0 >= (*flow)[f] ) continue; |
|
561 // Node w=g->head(f); |
|
562 // if ( level[w] == n && w != s ) { |
|
563 // bfs_queue.push(w); |
|
564 // Node first=level_list[l]; |
|
565 // if ( g->valid(first) ) left.set(first,w); |
|
566 // right.set(w,first); |
|
567 // level_list[l]=w; |
|
568 // level.set(w, l); |
|
569 // } |
|
570 // } |
|
571 // } |
|
572 |
|
573 |
|
574 // //the starting flow |
|
575 // OutEdgeIt e; |
|
576 // for(g->first(e,s); g->valid(e); g->next(e)) |
|
577 // { |
|
578 // Num rem=(*capacity)[e]-(*flow)[e]; |
|
579 // if ( rem <= 0 ) continue; |
|
580 // Node w=g->head(e); |
|
581 // if ( level[w] < n ) { |
|
582 // if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w); |
|
583 // flow->set(e, (*capacity)[e]); |
|
584 // excess.set(w, excess[w]+rem); |
|
585 // } |
|
586 // } |
|
587 |
|
588 // InEdgeIt f; |
|
589 // for(g->first(f,s); g->valid(f); g->next(f)) |
|
590 // { |
|
591 // if ( (*flow)[f] <= 0 ) continue; |
|
592 // Node w=g->tail(f); |
|
593 // if ( level[w] < n ) { |
|
594 // if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w); |
|
595 // excess.set(w, excess[w]+(*flow)[f]); |
|
596 // flow->set(f, 0); |
|
597 // } |
|
598 // } |
|
599 // break; |
|
600 // } //case PRE_FLOW |
|
601 // } |
|
602 // } //preflowPreproc |
|
603 |
|
604 |
|
605 |
|
606 // void relabel(Node w, int newlevel, VecStack& active, |
|
607 // VecNode& level_list, NNMap& left, |
|
608 // NNMap& right, int& b, int& k, bool what_heur ) |
|
609 // { |
|
610 |
|
611 // //FIXME jacint: ez mitol num |
|
612 // // Num lev=level[w]; |
|
613 // int lev=level[w]; |
|
614 |
|
615 // Node right_n=right[w]; |
|
616 // Node left_n=left[w]; |
|
617 |
|
618 // //unlacing starts |
|
619 // if ( g->valid(right_n) ) { |
|
620 // if ( g->valid(left_n) ) { |
|
621 // right.set(left_n, right_n); |
|
622 // left.set(right_n, left_n); |
|
623 // } else { |
|
624 // level_list[lev]=right_n; |
|
625 // left.set(right_n, INVALID); |
|
626 // } |
|
627 // } else { |
|
628 // if ( g->valid(left_n) ) { |
|
629 // right.set(left_n, INVALID); |
|
630 // } else { |
|
631 // level_list[lev]=INVALID; |
|
632 // } |
|
633 // } |
|
634 // //unlacing ends |
|
635 |
|
636 // if ( !g->valid(level_list[lev]) ) { |
|
637 |
|
638 // //gapping starts |
|
639 // for (int i=lev; i!=k ; ) { |
|
640 // Node v=level_list[++i]; |
|
641 // while ( g->valid(v) ) { |
|
642 // level.set(v,n); |
|
643 // v=right[v]; |
|
644 // } |
|
645 // level_list[i]=INVALID; |
|
646 // if ( !what_heur ) { |
|
647 // while ( !active[i].empty() ) { |
|
648 // active[i].pop(); //FIXME: ezt szebben kene |
|
649 // } |
|
650 // } |
|
651 // } |
|
652 |
|
653 // level.set(w,n); |
|
654 // b=lev-1; |
|
655 // k=b; |
|
656 // //gapping ends |
|
657 |
|
658 // } else { |
|
659 |
|
660 // if ( newlevel == n ) level.set(w,n); |
|
661 // else { |
|
662 // level.set(w,++newlevel); |
|
663 // active[newlevel].push(w); |
|
664 // if ( what_heur ) b=newlevel; |
|
665 // if ( k < newlevel ) ++k; //now k=newlevel |
|
666 // Node first=level_list[newlevel]; |
|
667 // if ( g->valid(first) ) left.set(first,w); |
|
668 // right.set(w,first); |
|
669 // left.set(w,INVALID); |
|
670 // level_list[newlevel]=w; |
|
671 // } |
|
672 // } |
|
673 |
|
674 // } //relabel |
|
675 |
|
676 // }; |
|
677 |
|
678 |
|
679 |
|
680 // template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
|
681 // void MaxFlow<Graph, Num, CapMap, FlowMap>::preflowPhase1(FlowEnum fe) |
|
682 // { |
|
683 |
|
684 // int heur0=(int)(H0*n); //time while running 'bound decrease' |
|
685 // int heur1=(int)(H1*n); //time while running 'highest label' |
|
686 // int heur=heur1; //starting time interval (#of relabels) |
|
687 // int numrelabel=0; |
|
688 |
|
689 // bool what_heur=1; |
|
690 // //It is 0 in case 'bound decrease' and 1 in case 'highest label' |
|
691 |
|
692 // bool end=false; |
|
693 // //Needed for 'bound decrease', true means no active nodes are above bound |
|
694 // //b. |
|
695 |
|
696 // int k=n-2; //bound on the highest level under n containing a node |
|
697 // int b=k; //bound on the highest level under n of an active node |
|
698 |
|
699 // VecStack active(n); |
|
700 |
|
701 // NNMap left(*g, INVALID); |
|
702 // NNMap right(*g, INVALID); |
|
703 // VecNode level_list(n,INVALID); |
|
704 // //List of the nodes in level i<n, set to n. |
|
705 |
|
706 // NodeIt v; |
|
707 // for(g->first(v); g->valid(v); g->next(v)) level.set(v,n); |
|
708 // //setting each node to level n |
|
709 |
|
710 // if ( fe == NO_FLOW ) { |
|
711 // EdgeIt e; |
|
712 // for(g->first(e); g->valid(e); g->next(e)) flow->set(e,0); |
|
713 // } |
|
714 |
|
715 // switch (fe) { //computing the excess |
|
716 // case PRE_FLOW: |
|
717 // { |
|
718 // NodeIt v; |
|
719 // for(g->first(v); g->valid(v); g->next(v)) { |
|
720 // Num exc=0; |
|
721 |
|
722 // InEdgeIt e; |
|
723 // for(g->first(e,v); g->valid(e); g->next(e)) exc+=(*flow)[e]; |
|
724 // OutEdgeIt f; |
|
725 // for(g->first(f,v); g->valid(f); g->next(f)) exc-=(*flow)[f]; |
|
726 |
|
727 // excess.set(v,exc); |
|
728 |
|
729 // //putting the active nodes into the stack |
|
730 // int lev=level[v]; |
|
731 // if ( exc > 0 && lev < n && v != t ) active[lev].push(v); |
|
732 // } |
|
733 // break; |
|
734 // } |
|
735 // case GEN_FLOW: |
|
736 // { |
|
737 // NodeIt v; |
|
738 // for(g->first(v); g->valid(v); g->next(v)) excess.set(v,0); |
|
739 |
|
740 // Num exc=0; |
|
741 // InEdgeIt e; |
|
742 // for(g->first(e,t); g->valid(e); g->next(e)) exc+=(*flow)[e]; |
|
743 // OutEdgeIt f; |
|
744 // for(g->first(f,t); g->valid(f); g->next(f)) exc-=(*flow)[f]; |
|
745 // excess.set(t,exc); |
|
746 // break; |
|
747 // } |
|
748 // case ZERO_FLOW: |
|
749 // case NO_FLOW: |
|
750 // { |
|
751 // NodeIt v; |
|
752 // for(g->first(v); g->valid(v); g->next(v)) excess.set(v,0); |
|
753 // break; |
|
754 // } |
|
755 // } |
|
756 |
|
757 // preflowPreproc(fe, active, level_list, left, right); |
|
758 // //End of preprocessing |
|
759 |
|
760 |
|
761 // //Push/relabel on the highest level active nodes. |
|
762 // while ( true ) { |
|
763 // if ( b == 0 ) { |
|
764 // if ( !what_heur && !end && k > 0 ) { |
|
765 // b=k; |
|
766 // end=true; |
|
767 // } else break; |
|
768 // } |
|
769 |
|
770 // if ( active[b].empty() ) --b; |
|
771 // else { |
|
772 // end=false; |
|
773 // Node w=active[b].top(); |
|
774 // active[b].pop(); |
|
775 // int newlevel=push(w,active); |
|
776 // if ( excess[w] > 0 ) relabel(w, newlevel, active, level_list, |
|
777 // left, right, b, k, what_heur); |
|
778 |
|
779 // ++numrelabel; |
|
780 // if ( numrelabel >= heur ) { |
|
781 // numrelabel=0; |
|
782 // if ( what_heur ) { |
|
783 // what_heur=0; |
|
784 // heur=heur0; |
|
785 // end=false; |
|
786 // } else { |
|
787 // what_heur=1; |
|
788 // heur=heur1; |
|
789 // b=k; |
|
790 // } |
|
791 // } |
|
792 // } |
|
793 // } |
|
794 |
|
795 // status=AFTER_PRE_FLOW_PHASE_1; |
|
796 // } |
|
797 |
|
798 |
|
799 |
|
800 // template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
|
801 // void MaxFlow<Graph, Num, CapMap, FlowMap>::preflowPhase2() |
|
802 // { |
|
803 |
|
804 // int k=n-2; //bound on the highest level under n containing a node |
|
805 // int b=k; //bound on the highest level under n of an active node |
|
806 |
|
807 // VecStack active(n); |
|
808 // level.set(s,0); |
|
809 // std::queue<Node> bfs_queue; |
|
810 // bfs_queue.push(s); |
|
811 |
|
812 // while (!bfs_queue.empty()) { |
|
813 |
|
814 // Node v=bfs_queue.front(); |
|
815 // bfs_queue.pop(); |
|
816 // int l=level[v]+1; |
|
817 |
|
818 // InEdgeIt e; |
|
819 // for(g->first(e,v); g->valid(e); g->next(e)) { |
|
820 // if ( (*capacity)[e] <= (*flow)[e] ) continue; |
|
821 // Node u=g->tail(e); |
|
822 // if ( level[u] >= n ) { |
|
823 // bfs_queue.push(u); |
|
824 // level.set(u, l); |
|
825 // if ( excess[u] > 0 ) active[l].push(u); |
|
826 // } |
|
827 // } |
|
828 |
|
829 // OutEdgeIt f; |
|
830 // for(g->first(f,v); g->valid(f); g->next(f)) { |
|
831 // if ( 0 >= (*flow)[f] ) continue; |
|
832 // Node u=g->head(f); |
|
833 // if ( level[u] >= n ) { |
|
834 // bfs_queue.push(u); |
|
835 // level.set(u, l); |
|
836 // if ( excess[u] > 0 ) active[l].push(u); |
|
837 // } |
|
838 // } |
|
839 // } |
|
840 // b=n-2; |
|
841 |
|
842 // while ( true ) { |
|
843 |
|
844 // if ( b == 0 ) break; |
|
845 |
|
846 // if ( active[b].empty() ) --b; |
|
847 // else { |
|
848 // Node w=active[b].top(); |
|
849 // active[b].pop(); |
|
850 // int newlevel=push(w,active); |
|
851 |
|
852 // //relabel |
|
853 // if ( excess[w] > 0 ) { |
|
854 // level.set(w,++newlevel); |
|
855 // active[newlevel].push(w); |
|
856 // b=newlevel; |
|
857 // } |
|
858 // } // if stack[b] is nonempty |
|
859 // } // while(true) |
|
860 |
|
861 // status=AFTER_PRE_FLOW_PHASE_2; |
|
862 // } |
|
863 |
|
864 |
|
865 template <typename Graph, typename Num, |
|
866 typename CapMap=typename Graph::template EdgeMap<Num>, |
|
867 typename FlowMap=typename Graph::template EdgeMap<Num> > |
|
868 class AugmentingFlow { |
|
869 protected: |
|
870 typedef typename Graph::Node Node; |
|
871 typedef typename Graph::NodeIt NodeIt; |
|
872 typedef typename Graph::EdgeIt EdgeIt; |
|
873 typedef typename Graph::OutEdgeIt OutEdgeIt; |
|
874 typedef typename Graph::InEdgeIt InEdgeIt; |
|
875 |
|
876 // typedef typename std::vector<std::stack<Node> > VecStack; |
|
877 // typedef typename Graph::template NodeMap<Node> NNMap; |
|
878 // typedef typename std::vector<Node> VecNode; |
|
879 |
|
880 const Graph* g; |
|
881 Node s; |
|
882 Node t; |
|
883 const CapMap* capacity; |
|
884 FlowMap* flow; |
|
885 // int n; //the number of nodes of G |
|
886 typedef ResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW; |
|
887 //typedef ExpResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW; |
|
888 typedef typename ResGW::OutEdgeIt ResGWOutEdgeIt; |
|
889 typedef typename ResGW::Edge ResGWEdge; |
|
890 //typedef typename ResGW::template NodeMap<bool> ReachedMap; |
|
891 typedef typename Graph::template NodeMap<int> ReachedMap; |
|
892 |
|
893 |
|
894 //level works as a bool map in augmenting path algorithms and is |
|
895 //used by bfs for storing reached information. In preflow, it |
|
896 //shows the levels of nodes. |
|
897 ReachedMap level; |
|
898 |
|
899 //excess is needed only in preflow |
|
900 // typename Graph::template NodeMap<Num> excess; |
|
901 |
|
902 //fixme |
|
903 // protected: |
|
904 // MaxFlow() { } |
|
905 // void set(const Graph& _G, Node _s, Node _t, const CapMap& _capacity, |
|
906 // FlowMap& _flow) |
|
907 // { |
|
908 // g=&_G; |
|
909 // s=_s; |
|
910 // t=_t; |
|
911 // capacity=&_capacity; |
|
912 // flow=&_flow; |
|
913 // n=_G.nodeNum; |
|
914 // level.set (_G); //kellene vmi ilyesmi fv |
|
915 // excess(_G,0); //itt is |
|
916 // } |
|
917 |
|
918 // constants used for heuristics |
|
919 // static const int H0=20; |
|
920 // static const int H1=1; |
|
921 |
|
922 public: |
|
923 |
|
924 ///Indicates the property of the starting flow. |
|
925 |
|
926 ///Indicates the property of the starting flow. The meanings are as follows: |
|
927 ///- \c ZERO_FLOW: constant zero flow |
|
928 ///- \c GEN_FLOW: any flow, i.e. the sum of the in-flows equals to |
|
929 ///the sum of the out-flows in every node except the \e source and |
|
930 ///the \e target. |
|
931 ///- \c PRE_FLOW: any preflow, i.e. the sum of the in-flows is at |
|
932 ///least the sum of the out-flows in every node except the \e source. |
|
933 ///- \c NO_FLOW: indicates an unspecified edge map. \ref flow will be |
|
934 ///set to the constant zero flow in the beginning of the algorithm in this case. |
|
935 enum FlowEnum{ |
|
936 ZERO_FLOW, |
|
937 GEN_FLOW, |
|
938 PRE_FLOW, |
|
939 NO_FLOW |
|
940 }; |
|
941 |
|
942 enum StatusEnum { |
|
943 AFTER_NOTHING, |
|
944 AFTER_AUGMENTING, |
|
945 AFTER_FAST_AUGMENTING, |
|
946 AFTER_PRE_FLOW_PHASE_1, |
|
947 AFTER_PRE_FLOW_PHASE_2 |
|
948 }; |
|
949 |
|
950 /// Don not needle this flag only if necessary. |
|
951 StatusEnum status; |
|
952 int number_of_augmentations; |
|
953 |
|
954 |
|
955 template<typename IntMap> |
|
956 class TrickyReachedMap { |
|
957 protected: |
|
958 IntMap* map; |
|
959 int* number_of_augmentations; |
|
960 public: |
|
961 TrickyReachedMap(IntMap& _map, int& _number_of_augmentations) : |
|
962 map(&_map), number_of_augmentations(&_number_of_augmentations) { } |
|
963 void set(const Node& n, bool b) { |
|
964 if (b) |
|
965 map->set(n, *number_of_augmentations); |
|
966 else |
|
967 map->set(n, *number_of_augmentations-1); |
|
968 } |
|
969 bool operator[](const Node& n) const { |
|
970 return (*map)[n]==*number_of_augmentations; |
|
971 } |
|
972 }; |
|
973 |
|
974 AugmentingFlow(const Graph& _G, Node _s, Node _t, const CapMap& _capacity, |
|
975 FlowMap& _flow) : |
|
976 g(&_G), s(_s), t(_t), capacity(&_capacity), |
|
977 flow(&_flow), //n(_G.nodeNum()), |
|
978 level(_G), //excess(_G,0), |
|
979 status(AFTER_NOTHING), number_of_augmentations(0) { } |
|
980 |
|
981 /// Starting from a flow, this method searches for an augmenting path |
|
982 /// according to the Edmonds-Karp algorithm |
|
983 /// and augments the flow on if any. |
|
984 /// The return value shows if the augmentation was succesful. |
|
985 bool augmentOnShortestPath(); |
|
986 bool augmentOnShortestPath2(); |
|
987 |
|
988 /// Starting from a flow, this method searches for an augmenting blocking |
|
989 /// flow according to Dinits' algorithm and augments the flow on if any. |
|
990 /// The blocking flow is computed in a physically constructed |
|
991 /// residual graph of type \c Mutablegraph. |
|
992 /// The return value show sif the augmentation was succesful. |
|
993 template<typename MutableGraph> bool augmentOnBlockingFlow(); |
|
994 |
|
995 /// The same as \c augmentOnBlockingFlow<MutableGraph> but the |
|
996 /// residual graph is not constructed physically. |
|
997 /// The return value shows if the augmentation was succesful. |
|
998 bool augmentOnBlockingFlow2(); |
|
999 |
|
1000 template<typename _CutMap> |
|
1001 void actMinCut(_CutMap& M) const { |
|
1002 NodeIt v; |
|
1003 switch (status) { |
|
1004 case AFTER_PRE_FLOW_PHASE_1: |
|
1005 // std::cout << "AFTER_PRE_FLOW_PHASE_1" << std::endl; |
|
1006 // for(g->first(v); g->valid(v); g->next(v)) { |
|
1007 // if (level[v] < n) { |
|
1008 // M.set(v, false); |
|
1009 // } else { |
|
1010 // M.set(v, true); |
|
1011 // } |
|
1012 // } |
|
1013 break; |
|
1014 case AFTER_PRE_FLOW_PHASE_2: |
|
1015 // std::cout << "AFTER_PRE_FLOW_PHASE_2" << std::endl; |
|
1016 break; |
|
1017 case AFTER_NOTHING: |
|
1018 // std::cout << "AFTER_NOTHING" << std::endl; |
|
1019 minMinCut(M); |
|
1020 break; |
|
1021 case AFTER_AUGMENTING: |
|
1022 // std::cout << "AFTER_AUGMENTING" << std::endl; |
|
1023 for(g->first(v); g->valid(v); g->next(v)) { |
|
1024 if (level[v]) { |
|
1025 M.set(v, true); |
|
1026 } else { |
|
1027 M.set(v, false); |
|
1028 } |
|
1029 } |
|
1030 break; |
|
1031 case AFTER_FAST_AUGMENTING: |
|
1032 // std::cout << "AFTER_FAST_AUGMENTING" << std::endl; |
|
1033 for(g->first(v); g->valid(v); g->next(v)) { |
|
1034 if (level[v]==number_of_augmentations) { |
|
1035 M.set(v, true); |
|
1036 } else { |
|
1037 M.set(v, false); |
|
1038 } |
|
1039 } |
|
1040 break; |
|
1041 } |
|
1042 } |
|
1043 |
|
1044 template<typename _CutMap> |
|
1045 void minMinCut(_CutMap& M) const { |
|
1046 std::queue<Node> queue; |
|
1047 |
|
1048 M.set(s,true); |
|
1049 queue.push(s); |
|
1050 |
|
1051 while (!queue.empty()) { |
|
1052 Node w=queue.front(); |
|
1053 queue.pop(); |
|
1054 |
|
1055 OutEdgeIt e; |
|
1056 for(g->first(e,w) ; g->valid(e); g->next(e)) { |
|
1057 Node v=g->head(e); |
|
1058 if (!M[v] && (*flow)[e] < (*capacity)[e] ) { |
|
1059 queue.push(v); |
|
1060 M.set(v, true); |
|
1061 } |
|
1062 } |
|
1063 |
|
1064 InEdgeIt f; |
|
1065 for(g->first(f,w) ; g->valid(f); g->next(f)) { |
|
1066 Node v=g->tail(f); |
|
1067 if (!M[v] && (*flow)[f] > 0 ) { |
|
1068 queue.push(v); |
|
1069 M.set(v, true); |
|
1070 } |
|
1071 } |
|
1072 } |
|
1073 } |
|
1074 |
|
1075 template<typename _CutMap> |
|
1076 void minMinCut2(_CutMap& M) const { |
|
1077 ResGW res_graph(*g, *capacity, *flow); |
|
1078 BfsIterator<ResGW, _CutMap> bfs(res_graph, M); |
|
1079 bfs.pushAndSetReached(s); |
|
1080 while (!bfs.finished()) ++bfs; |
|
1081 } |
|
1082 |
|
1083 Num flowValue() const { |
|
1084 Num a=0; |
|
1085 FOR_EACH_INC_LOC(InEdgeIt, e, *g, t) a+=(*flow)[e]; |
|
1086 FOR_EACH_INC_LOC(OutEdgeIt, e, *g, t) a-=(*flow)[e]; |
|
1087 return a; |
|
1088 //marci figyu: excess[t] epp ezt adja preflow 1. fazisa utan |
|
1089 } |
|
1090 |
|
1091 template<typename MapGraphWrapper> |
|
1092 class DistanceMap { |
|
1093 protected: |
|
1094 const MapGraphWrapper* g; |
|
1095 typename MapGraphWrapper::template NodeMap<int> dist; |
|
1096 public: |
|
1097 DistanceMap(MapGraphWrapper& _g) : g(&_g), dist(*g, g->nodeNum()) { } |
|
1098 void set(const typename MapGraphWrapper::Node& n, int a) { |
|
1099 dist.set(n, a); |
|
1100 } |
|
1101 int operator[](const typename MapGraphWrapper::Node& n) const { |
|
1102 return dist[n]; |
|
1103 } |
|
1104 // int get(const typename MapGraphWrapper::Node& n) const { |
|
1105 // return dist[n]; } |
|
1106 // bool get(const typename MapGraphWrapper::Edge& e) const { |
|
1107 // return (dist.get(g->tail(e))<dist.get(g->head(e))); } |
|
1108 bool operator[](const typename MapGraphWrapper::Edge& e) const { |
|
1109 return (dist[g->tail(e)]<dist[g->head(e)]); |
|
1110 } |
|
1111 }; |
|
1112 |
|
1113 }; |
|
1114 |
|
1115 |
|
1116 |
|
1117 template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
|
1118 bool AugmentingFlow<Graph, Num, CapMap, FlowMap>::augmentOnShortestPath() |
|
1119 { |
|
1120 ResGW res_graph(*g, *capacity, *flow); |
|
1121 bool _augment=false; |
|
1122 |
|
1123 //ReachedMap level(res_graph); |
|
1124 FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0); |
|
1125 BfsIterator<ResGW, ReachedMap> bfs(res_graph, level); |
|
1126 bfs.pushAndSetReached(s); |
|
1127 |
|
1128 typename ResGW::template NodeMap<ResGWEdge> pred(res_graph); |
|
1129 pred.set(s, INVALID); |
|
1130 |
|
1131 typename ResGW::template NodeMap<Num> free(res_graph); |
|
1132 |
|
1133 //searching for augmenting path |
|
1134 while ( !bfs.finished() ) { |
|
1135 ResGWOutEdgeIt e=bfs; |
|
1136 if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) { |
|
1137 Node v=res_graph.tail(e); |
|
1138 Node w=res_graph.head(e); |
|
1139 pred.set(w, e); |
|
1140 if (res_graph.valid(pred[v])) { |
|
1141 free.set(w, std::min(free[v], res_graph.resCap(e))); |
|
1142 } else { |
|
1143 free.set(w, res_graph.resCap(e)); |
|
1144 } |
|
1145 if (res_graph.head(e)==t) { _augment=true; break; } |
|
1146 } |
|
1147 |
|
1148 ++bfs; |
|
1149 } //end of searching augmenting path |
|
1150 |
|
1151 if (_augment) { |
|
1152 Node n=t; |
|
1153 Num augment_value=free[t]; |
|
1154 while (res_graph.valid(pred[n])) { |
|
1155 ResGWEdge e=pred[n]; |
|
1156 res_graph.augment(e, augment_value); |
|
1157 n=res_graph.tail(e); |
|
1158 } |
|
1159 } |
|
1160 |
|
1161 status=AFTER_AUGMENTING; |
|
1162 return _augment; |
|
1163 } |
|
1164 |
|
1165 template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
|
1166 bool AugmentingFlow<Graph, Num, CapMap, FlowMap>::augmentOnShortestPath2() |
|
1167 { |
|
1168 ResGW res_graph(*g, *capacity, *flow); |
|
1169 bool _augment=false; |
|
1170 |
|
1171 if (status!=AFTER_FAST_AUGMENTING) { |
|
1172 FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0); |
|
1173 number_of_augmentations=1; |
|
1174 } else { |
|
1175 ++number_of_augmentations; |
|
1176 } |
|
1177 TrickyReachedMap<ReachedMap> |
|
1178 tricky_reached_map(level, number_of_augmentations); |
|
1179 //ReachedMap level(res_graph); |
|
1180 // FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0); |
|
1181 BfsIterator<ResGW, TrickyReachedMap<ReachedMap> > |
|
1182 bfs(res_graph, tricky_reached_map); |
|
1183 bfs.pushAndSetReached(s); |
|
1184 |
|
1185 typename ResGW::template NodeMap<ResGWEdge> pred(res_graph); |
|
1186 pred.set(s, INVALID); |
|
1187 |
|
1188 typename ResGW::template NodeMap<Num> free(res_graph); |
|
1189 |
|
1190 //searching for augmenting path |
|
1191 while ( !bfs.finished() ) { |
|
1192 ResGWOutEdgeIt e=bfs; |
|
1193 if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) { |
|
1194 Node v=res_graph.tail(e); |
|
1195 Node w=res_graph.head(e); |
|
1196 pred.set(w, e); |
|
1197 if (res_graph.valid(pred[v])) { |
|
1198 free.set(w, std::min(free[v], res_graph.resCap(e))); |
|
1199 } else { |
|
1200 free.set(w, res_graph.resCap(e)); |
|
1201 } |
|
1202 if (res_graph.head(e)==t) { _augment=true; break; } |
|
1203 } |
|
1204 |
|
1205 ++bfs; |
|
1206 } //end of searching augmenting path |
|
1207 |
|
1208 if (_augment) { |
|
1209 Node n=t; |
|
1210 Num augment_value=free[t]; |
|
1211 while (res_graph.valid(pred[n])) { |
|
1212 ResGWEdge e=pred[n]; |
|
1213 res_graph.augment(e, augment_value); |
|
1214 n=res_graph.tail(e); |
|
1215 } |
|
1216 } |
|
1217 |
|
1218 status=AFTER_FAST_AUGMENTING; |
|
1219 return _augment; |
|
1220 } |
|
1221 |
|
1222 |
|
1223 template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
|
1224 template<typename MutableGraph> |
|
1225 bool AugmentingFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow() |
|
1226 { |
|
1227 typedef MutableGraph MG; |
|
1228 bool _augment=false; |
|
1229 |
|
1230 ResGW res_graph(*g, *capacity, *flow); |
|
1231 |
|
1232 //bfs for distances on the residual graph |
|
1233 //ReachedMap level(res_graph); |
|
1234 FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0); |
|
1235 BfsIterator<ResGW, ReachedMap> bfs(res_graph, level); |
|
1236 bfs.pushAndSetReached(s); |
|
1237 typename ResGW::template NodeMap<int> |
|
1238 dist(res_graph); //filled up with 0's |
|
1239 |
|
1240 //F will contain the physical copy of the residual graph |
|
1241 //with the set of edges which are on shortest paths |
|
1242 MG F; |
|
1243 typename ResGW::template NodeMap<typename MG::Node> |
|
1244 res_graph_to_F(res_graph); |
|
1245 { |
|
1246 typename ResGW::NodeIt n; |
|
1247 for(res_graph.first(n); res_graph.valid(n); res_graph.next(n)) { |
|
1248 res_graph_to_F.set(n, F.addNode()); |
|
1249 } |
|
1250 } |
|
1251 |
|
1252 typename MG::Node sF=res_graph_to_F[s]; |
|
1253 typename MG::Node tF=res_graph_to_F[t]; |
|
1254 typename MG::template EdgeMap<ResGWEdge> original_edge(F); |
|
1255 typename MG::template EdgeMap<Num> residual_capacity(F); |
|
1256 |
|
1257 while ( !bfs.finished() ) { |
|
1258 ResGWOutEdgeIt e=bfs; |
|
1259 if (res_graph.valid(e)) { |
|
1260 if (bfs.isBNodeNewlyReached()) { |
|
1261 dist.set(res_graph.head(e), dist[res_graph.tail(e)]+1); |
|
1262 typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)], |
|
1263 res_graph_to_F[res_graph.head(e)]); |
|
1264 original_edge.update(); |
|
1265 original_edge.set(f, e); |
|
1266 residual_capacity.update(); |
|
1267 residual_capacity.set(f, res_graph.resCap(e)); |
|
1268 } else { |
|
1269 if (dist[res_graph.head(e)]==(dist[res_graph.tail(e)]+1)) { |
|
1270 typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)], |
|
1271 res_graph_to_F[res_graph.head(e)]); |
|
1272 original_edge.update(); |
|
1273 original_edge.set(f, e); |
|
1274 residual_capacity.update(); |
|
1275 residual_capacity.set(f, res_graph.resCap(e)); |
|
1276 } |
|
1277 } |
|
1278 } |
|
1279 ++bfs; |
|
1280 } //computing distances from s in the residual graph |
|
1281 |
|
1282 bool __augment=true; |
|
1283 |
|
1284 while (__augment) { |
|
1285 __augment=false; |
|
1286 //computing blocking flow with dfs |
|
1287 DfsIterator< MG, typename MG::template NodeMap<bool> > dfs(F); |
|
1288 typename MG::template NodeMap<typename MG::Edge> pred(F); |
|
1289 pred.set(sF, INVALID); |
|
1290 //invalid iterators for sources |
|
1291 |
|
1292 typename MG::template NodeMap<Num> free(F); |
|
1293 |
|
1294 dfs.pushAndSetReached(sF); |
|
1295 while (!dfs.finished()) { |
|
1296 ++dfs; |
|
1297 if (F.valid(/*typename MG::OutEdgeIt*/(dfs))) { |
|
1298 if (dfs.isBNodeNewlyReached()) { |
|
1299 typename MG::Node v=F.aNode(dfs); |
|
1300 typename MG::Node w=F.bNode(dfs); |
|
1301 pred.set(w, dfs); |
|
1302 if (F.valid(pred[v])) { |
|
1303 free.set(w, std::min(free[v], residual_capacity[dfs])); |
|
1304 } else { |
|
1305 free.set(w, residual_capacity[dfs]); |
|
1306 } |
|
1307 if (w==tF) { |
|
1308 __augment=true; |
|
1309 _augment=true; |
|
1310 break; |
|
1311 } |
|
1312 |
|
1313 } else { |
|
1314 F.erase(/*typename MG::OutEdgeIt*/(dfs)); |
|
1315 } |
|
1316 } |
|
1317 } |
|
1318 |
|
1319 if (__augment) { |
|
1320 typename MG::Node n=tF; |
|
1321 Num augment_value=free[tF]; |
|
1322 while (F.valid(pred[n])) { |
|
1323 typename MG::Edge e=pred[n]; |
|
1324 res_graph.augment(original_edge[e], augment_value); |
|
1325 n=F.tail(e); |
|
1326 if (residual_capacity[e]==augment_value) |
|
1327 F.erase(e); |
|
1328 else |
|
1329 residual_capacity.set(e, residual_capacity[e]-augment_value); |
|
1330 } |
|
1331 } |
|
1332 |
|
1333 } |
|
1334 |
|
1335 status=AFTER_AUGMENTING; |
|
1336 return _augment; |
|
1337 } |
|
1338 |
|
1339 |
|
1340 |
|
1341 |
|
1342 template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
|
1343 bool AugmentingFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow2() |
|
1344 { |
|
1345 bool _augment=false; |
|
1346 |
|
1347 ResGW res_graph(*g, *capacity, *flow); |
|
1348 |
|
1349 //ReachedMap level(res_graph); |
|
1350 FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0); |
|
1351 BfsIterator<ResGW, ReachedMap> bfs(res_graph, level); |
|
1352 |
|
1353 bfs.pushAndSetReached(s); |
|
1354 DistanceMap<ResGW> dist(res_graph); |
|
1355 while ( !bfs.finished() ) { |
|
1356 ResGWOutEdgeIt e=bfs; |
|
1357 if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) { |
|
1358 dist.set(res_graph.head(e), dist[res_graph.tail(e)]+1); |
|
1359 } |
|
1360 ++bfs; |
|
1361 } //computing distances from s in the residual graph |
|
1362 |
|
1363 //Subgraph containing the edges on some shortest paths |
|
1364 ConstMap<typename ResGW::Node, bool> true_map(true); |
|
1365 typedef SubGraphWrapper<ResGW, ConstMap<typename ResGW::Node, bool>, |
|
1366 DistanceMap<ResGW> > FilterResGW; |
|
1367 FilterResGW filter_res_graph(res_graph, true_map, dist); |
|
1368 |
|
1369 //Subgraph, which is able to delete edges which are already |
|
1370 //met by the dfs |
|
1371 typename FilterResGW::template NodeMap<typename FilterResGW::OutEdgeIt> |
|
1372 first_out_edges(filter_res_graph); |
|
1373 typename FilterResGW::NodeIt v; |
|
1374 for(filter_res_graph.first(v); filter_res_graph.valid(v); |
|
1375 filter_res_graph.next(v)) |
|
1376 { |
|
1377 typename FilterResGW::OutEdgeIt e; |
|
1378 filter_res_graph.first(e, v); |
|
1379 first_out_edges.set(v, e); |
|
1380 } |
|
1381 typedef ErasingFirstGraphWrapper<FilterResGW, typename FilterResGW:: |
|
1382 template NodeMap<typename FilterResGW::OutEdgeIt> > ErasingResGW; |
|
1383 ErasingResGW erasing_res_graph(filter_res_graph, first_out_edges); |
|
1384 |
|
1385 bool __augment=true; |
|
1386 |
|
1387 while (__augment) { |
|
1388 |
|
1389 __augment=false; |
|
1390 //computing blocking flow with dfs |
|
1391 DfsIterator< ErasingResGW, |
|
1392 typename ErasingResGW::template NodeMap<bool> > |
|
1393 dfs(erasing_res_graph); |
|
1394 typename ErasingResGW:: |
|
1395 template NodeMap<typename ErasingResGW::OutEdgeIt> |
|
1396 pred(erasing_res_graph); |
|
1397 pred.set(s, INVALID); |
|
1398 //invalid iterators for sources |
|
1399 |
|
1400 typename ErasingResGW::template NodeMap<Num> |
|
1401 free1(erasing_res_graph); |
|
1402 |
|
1403 dfs.pushAndSetReached |
|
1404 ///\bug hugo 0.2 |
|
1405 (typename ErasingResGW::Node |
|
1406 (typename FilterResGW::Node |
|
1407 (typename ResGW::Node(s) |
|
1408 ) |
|
1409 ) |
|
1410 ); |
|
1411 while (!dfs.finished()) { |
|
1412 ++dfs; |
|
1413 if (erasing_res_graph.valid(typename ErasingResGW::OutEdgeIt(dfs))) |
|
1414 { |
|
1415 if (dfs.isBNodeNewlyReached()) { |
|
1416 |
|
1417 typename ErasingResGW::Node v=erasing_res_graph.aNode(dfs); |
|
1418 typename ErasingResGW::Node w=erasing_res_graph.bNode(dfs); |
|
1419 |
|
1420 pred.set(w, /*typename ErasingResGW::OutEdgeIt*/(dfs)); |
|
1421 if (erasing_res_graph.valid(pred[v])) { |
|
1422 free1.set |
|
1423 (w, std::min(free1[v], res_graph.resCap |
|
1424 (typename ErasingResGW::OutEdgeIt(dfs)))); |
|
1425 } else { |
|
1426 free1.set |
|
1427 (w, res_graph.resCap |
|
1428 (typename ErasingResGW::OutEdgeIt(dfs))); |
|
1429 } |
|
1430 |
|
1431 if (w==t) { |
|
1432 __augment=true; |
|
1433 _augment=true; |
|
1434 break; |
|
1435 } |
|
1436 } else { |
|
1437 erasing_res_graph.erase(dfs); |
|
1438 } |
|
1439 } |
|
1440 } |
|
1441 |
|
1442 if (__augment) { |
|
1443 typename ErasingResGW::Node |
|
1444 n=typename FilterResGW::Node(typename ResGW::Node(t)); |
|
1445 // typename ResGW::NodeMap<Num> a(res_graph); |
|
1446 // typename ResGW::Node b; |
|
1447 // Num j=a[b]; |
|
1448 // typename FilterResGW::NodeMap<Num> a1(filter_res_graph); |
|
1449 // typename FilterResGW::Node b1; |
|
1450 // Num j1=a1[b1]; |
|
1451 // typename ErasingResGW::NodeMap<Num> a2(erasing_res_graph); |
|
1452 // typename ErasingResGW::Node b2; |
|
1453 // Num j2=a2[b2]; |
|
1454 Num augment_value=free1[n]; |
|
1455 while (erasing_res_graph.valid(pred[n])) { |
|
1456 typename ErasingResGW::OutEdgeIt e=pred[n]; |
|
1457 res_graph.augment(e, augment_value); |
|
1458 n=erasing_res_graph.tail(e); |
|
1459 if (res_graph.resCap(e)==0) |
|
1460 erasing_res_graph.erase(e); |
|
1461 } |
|
1462 } |
|
1463 |
|
1464 } //while (__augment) |
|
1465 |
|
1466 status=AFTER_AUGMENTING; |
|
1467 return _augment; |
|
1468 } |
|
1469 |
|
1470 |
|
1471 } //namespace hugo |
|
1472 |
|
1473 #endif //HUGO_AUGMENTING_FLOW_H |
|
1474 |
|
1475 |
|
1476 |
|
1477 |