[140] | 1 | // -*- C++ -*- |
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| 2 | |
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| 3 | //hogy kell azt megcsinalni hogy a konstruktorban a FlowMap-nek legyen default erteke (a 0 map) |
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| 4 | |
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| 5 | /* |
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| 6 | preflow_aug.h |
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| 7 | by jacint. |
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| 8 | |
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| 9 | The same as preflow.h, the only difference is that here |
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| 10 | we start from a given flow. |
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| 11 | |
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| 12 | |
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| 13 | The constructor runs the algorithm: |
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| 14 | |
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| 15 | template <typename Graph, typename T, |
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| 16 | typename Graph_EdgeMap_T_1=typename Graph::EdgeMap<T>, |
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| 17 | typename Graph_EdgeMap_T_2=typename Graph::EdgeMap<T> > |
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| 18 | PreflowAug(Graph G, G_NodeIt s, G_NodeIt t, G_EdgeMap_T_1 capacity, |
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| 19 | G_EdgeMap_T_2 flow, bool flow_type) |
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| 20 | |
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| 21 | 'capacity' must be non-negative, if flow_type=0 then |
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| 22 | 'flow' must be a flow, otherwise it must be a preflow. |
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| 23 | |
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| 24 | |
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| 25 | Members: |
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| 26 | |
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| 27 | T maxFlow() : returns the value of a maximum flow |
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| 28 | |
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| 29 | T flow(G_EdgeIt e) : for a fixed maximum flow x it returns x(e) |
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| 30 | |
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| 31 | G_EdgeMap_T_2 flow() : returns the fixed maximum flow x |
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| 32 | |
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| 33 | void minMinCut(G_NodeMap_bool& M) : |
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| 34 | sets M to the characteristic vector of the |
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| 35 | minimum min cut. M must be initialized to false. |
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| 36 | |
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| 37 | void maxMinCut(G_NodeMap_bool& M) : |
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| 38 | sets M to the characteristic vector of the |
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| 39 | maximum min cut. M must be initialized to false. |
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| 40 | |
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| 41 | void minCut(G_NodeMap_bool& M) : |
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| 42 | sets M to the characteristic vector of a |
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| 43 | min cut. M must be initialized to false. |
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| 44 | */ |
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| 45 | |
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| 46 | #ifndef PREFLOW_H |
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| 47 | #define PREFLOW_H |
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| 48 | |
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| 49 | #define H0 20 |
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| 50 | #define H1 1 |
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| 51 | |
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| 52 | #include <vector> |
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| 53 | #include <queue> |
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| 54 | |
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| 55 | #include <iostream> //for error handling |
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| 56 | |
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| 57 | #include <time_measure.h> |
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| 58 | |
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| 59 | namespace hugo { |
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| 60 | |
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| 61 | template <typename Graph, typename T, |
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| 62 | typename CapMap=typename Graph::EdgeMap<T>, |
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| 63 | typename FlowMap=typename Graph::EdgeMap<T> > |
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| 64 | class PreflowAug { |
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| 65 | |
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| 66 | typedef typename Graph::NodeIt NodeIt; |
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| 67 | typedef typename Graph::EdgeIt EdgeIt; |
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| 68 | typedef typename Graph::EachNodeIt EachNodeIt; |
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| 69 | typedef typename Graph::EachEdgeIt EachEdgeIt; |
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| 70 | typedef typename Graph::OutEdgeIt OutEdgeIt; |
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| 71 | typedef typename Graph::InEdgeIt InEdgeIt; |
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| 72 | |
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| 73 | Graph& G; |
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| 74 | NodeIt s; |
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| 75 | NodeIt t; |
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| 76 | CapMap& capacity; |
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| 77 | FlowMap& _flow; |
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| 78 | bool flow_type; |
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| 79 | T value; |
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| 80 | |
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| 81 | public: |
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| 82 | double time; |
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| 83 | PreflowAug(Graph& _G, NodeIt _s, NodeIt _t, |
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| 84 | CapMap& _capacity, FlowMap& __flow, bool _flow_type ) : |
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| 85 | G(_G), s(_s), t(_t), capacity(_capacity), _flow(__flow), |
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| 86 | flow_type(_flow_type) |
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| 87 | { |
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| 88 | |
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| 89 | |
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| 90 | bool phase=0; //phase 0 is the 1st phase, phase 1 is the 2nd |
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| 91 | int n=G.nodeNum(); |
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| 92 | int heur0=(int)(H0*n); //time while running 'bound decrease' |
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| 93 | int heur1=(int)(H1*n); //time while running 'highest label' |
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| 94 | int heur=heur1; //starting time interval (#of relabels) |
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| 95 | bool what_heur=1; |
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| 96 | /* |
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| 97 | what_heur is 0 in case 'bound decrease' |
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| 98 | and 1 in case 'highest label' |
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| 99 | */ |
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| 100 | bool end=false; |
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| 101 | /* |
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| 102 | Needed for 'bound decrease', 'true' |
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| 103 | means no active nodes are above bound b. |
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| 104 | */ |
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| 105 | int relabel=0; |
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| 106 | int k=n-2; //bound on the highest level under n containing a node |
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| 107 | int b=k; //bound on the highest level under n of an active node |
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| 108 | |
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| 109 | typename Graph::NodeMap<int> level(G,n); |
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| 110 | typename Graph::NodeMap<T> excess(G); |
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| 111 | |
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| 112 | std::vector<NodeIt> active(n); |
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| 113 | typename Graph::NodeMap<NodeIt> next(G); |
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| 114 | //Stack of the active nodes in level i < n. |
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| 115 | //We use it in both phases. |
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| 116 | |
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| 117 | typename Graph::NodeMap<NodeIt> left(G); |
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| 118 | typename Graph::NodeMap<NodeIt> right(G); |
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| 119 | std::vector<NodeIt> level_list(n); |
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| 120 | /* |
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| 121 | List of the nodes in level i<n. |
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| 122 | */ |
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| 123 | |
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| 124 | /*Reverse_bfs from t, to find the starting level.*/ |
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| 125 | level.set(t,0); |
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| 126 | std::queue<NodeIt> bfs_queue; |
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| 127 | bfs_queue.push(t); |
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| 128 | |
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| 129 | |
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| 130 | while (!bfs_queue.empty()) { |
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| 131 | |
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| 132 | NodeIt v=bfs_queue.front(); |
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| 133 | bfs_queue.pop(); |
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| 134 | int l=level.get(v)+1; |
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| 135 | |
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| 136 | for(InEdgeIt e=G.template first<InEdgeIt>(v); e.valid(); ++e) { |
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| 137 | if ( capacity.get(e) == _flow.get(e) ) continue; |
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| 138 | NodeIt w=G.tail(e); |
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| 139 | if ( level.get(w) == n && w != s ) { |
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| 140 | bfs_queue.push(w); |
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| 141 | NodeIt first=level_list[l]; |
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| 142 | if ( first.valid() ) left.set(first,w); |
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| 143 | right.set(w,first); |
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| 144 | level_list[l]=w; |
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| 145 | level.set(w, l); |
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| 146 | } |
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| 147 | } |
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| 148 | |
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| 149 | for(OutEdgeIt e=G.template first<OutEdgeIt>(v); e.valid(); ++e) { |
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| 150 | if ( 0 == _flow.get(e) ) continue; |
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| 151 | NodeIt w=G.head(e); |
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| 152 | if ( level.get(w) == n && w != s ) { |
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| 153 | bfs_queue.push(w); |
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| 154 | NodeIt first=level_list[l]; |
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| 155 | if ( first != 0 ) left.set(first,w); |
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| 156 | right.set(w,first); |
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| 157 | level_list[l]=w; |
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| 158 | level.set(w, l); |
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| 159 | } |
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| 160 | } |
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| 161 | } |
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| 162 | |
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| 163 | level.set(s,n); |
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| 164 | |
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| 165 | |
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| 166 | |
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| 167 | /*The starting excess.*/ |
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| 168 | if ( flow_type ) { |
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| 169 | for(EachEdgeIt e=G.template first<EachEdgeIt>(); e.valid(); ++e) { |
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| 170 | if ( _flow.get(e) > 0 ) { |
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| 171 | T flo=_flow.get(e); |
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| 172 | NodeIt u=G.tail(e); |
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| 173 | NodeIt v=G.head(e); |
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| 174 | excess.set(u, excess.get(u)-flo); |
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| 175 | excess.set(v, excess.get(v)+flo); |
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| 176 | } |
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| 177 | } |
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| 178 | |
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| 179 | for(EachNodeIt v=G.template first<EachNodeIt>(); v.valid(); ++v) { |
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| 180 | if ( excess.get(v) < 0 ) { |
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| 181 | std::cerr<<"It is not a pre_flow."<<std::endl; |
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| 182 | exit(1); |
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| 183 | } else { |
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| 184 | next.set(v,active[level.get(v)]); |
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| 185 | active[level.get(v)]=v;} |
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| 186 | } |
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| 187 | } |
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| 188 | |
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| 189 | |
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| 190 | /* Starting flow. It is everywhere 0 at the moment. */ |
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| 191 | for(OutEdgeIt e=G.template first<OutEdgeIt>(s); e.valid(); ++e) |
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| 192 | { |
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| 193 | T c=capacity.get(e)-_flow.get(e); |
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| 194 | if ( c == 0 ) continue; |
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| 195 | NodeIt w=G.head(e); |
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| 196 | if ( level.get(w) < n ) { |
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| 197 | if ( excess.get(w) == 0 && w!=t ) { |
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| 198 | next.set(w,active[level.get(w)]); |
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| 199 | active[level.get(w)]=w; |
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| 200 | } |
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| 201 | _flow.set(e, capacity.get(e)); |
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| 202 | excess.set(w, excess.get(w)+c); |
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| 203 | } |
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| 204 | } |
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| 205 | |
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| 206 | /* |
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| 207 | End of preprocessing |
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| 208 | */ |
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| 209 | |
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| 210 | |
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| 211 | |
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| 212 | /* |
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| 213 | Push/relabel on the highest level active nodes. |
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| 214 | */ |
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| 215 | while ( true ) { |
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| 216 | |
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| 217 | if ( b == 0 ) { |
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| 218 | if ( phase ) break; |
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| 219 | |
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| 220 | if ( !what_heur && !end && k > 0 ) { |
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| 221 | b=k; |
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| 222 | end=true; |
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| 223 | } else { |
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| 224 | phase=1; |
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| 225 | time=currTime(); |
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| 226 | level.set(s,0); |
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| 227 | std::queue<NodeIt> bfs_queue; |
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| 228 | bfs_queue.push(s); |
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| 229 | |
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| 230 | while (!bfs_queue.empty()) { |
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| 231 | |
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| 232 | NodeIt v=bfs_queue.front(); |
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| 233 | bfs_queue.pop(); |
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| 234 | int l=level.get(v)+1; |
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| 235 | |
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| 236 | for(InEdgeIt e=G.template first<InEdgeIt>(v); e.valid(); ++e) { |
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| 237 | if ( capacity.get(e) == _flow.get(e) ) continue; |
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| 238 | NodeIt u=G.tail(e); |
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| 239 | if ( level.get(u) >= n ) { |
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| 240 | bfs_queue.push(u); |
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| 241 | level.set(u, l); |
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| 242 | if ( excess.get(u) > 0 ) { |
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| 243 | next.set(u,active[l]); |
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| 244 | active[l]=u; |
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| 245 | } |
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| 246 | } |
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| 247 | } |
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| 248 | |
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| 249 | for(OutEdgeIt e=G.template first<OutEdgeIt>(v); e.valid(); ++e) { |
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| 250 | if ( 0 == _flow.get(e) ) continue; |
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| 251 | NodeIt u=G.head(e); |
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| 252 | if ( level.get(u) >= n ) { |
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| 253 | bfs_queue.push(u); |
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| 254 | level.set(u, l); |
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| 255 | if ( excess.get(u) > 0 ) { |
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| 256 | next.set(u,active[l]); |
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| 257 | active[l]=u; |
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| 258 | } |
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| 259 | } |
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| 260 | } |
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| 261 | } |
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| 262 | b=n-2; |
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| 263 | } |
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| 264 | |
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| 265 | } |
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| 266 | |
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| 267 | |
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| 268 | if ( active[b] == 0 ) --b; |
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| 269 | else { |
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| 270 | end=false; |
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| 271 | |
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| 272 | NodeIt w=active[b]; |
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| 273 | active[b]=next.get(w); |
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| 274 | int lev=level.get(w); |
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| 275 | T exc=excess.get(w); |
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| 276 | int newlevel=n; //bound on the next level of w |
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| 277 | |
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| 278 | for(OutEdgeIt e=G.template first<OutEdgeIt>(w); e.valid(); ++e) { |
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| 279 | |
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| 280 | if ( _flow.get(e) == capacity.get(e) ) continue; |
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| 281 | NodeIt v=G.head(e); |
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| 282 | //e=wv |
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| 283 | |
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| 284 | if( lev > level.get(v) ) { |
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| 285 | /*Push is allowed now*/ |
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| 286 | |
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| 287 | if ( excess.get(v)==0 && v!=t && v!=s ) { |
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| 288 | int lev_v=level.get(v); |
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| 289 | next.set(v,active[lev_v]); |
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| 290 | active[lev_v]=v; |
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| 291 | } |
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| 292 | |
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| 293 | T cap=capacity.get(e); |
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| 294 | T flo=_flow.get(e); |
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| 295 | T remcap=cap-flo; |
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| 296 | |
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| 297 | if ( remcap >= exc ) { |
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| 298 | /*A nonsaturating push.*/ |
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| 299 | |
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| 300 | _flow.set(e, flo+exc); |
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| 301 | excess.set(v, excess.get(v)+exc); |
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| 302 | exc=0; |
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| 303 | break; |
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| 304 | |
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| 305 | } else { |
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| 306 | /*A saturating push.*/ |
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| 307 | |
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| 308 | _flow.set(e, cap); |
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| 309 | excess.set(v, excess.get(v)+remcap); |
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| 310 | exc-=remcap; |
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| 311 | } |
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| 312 | } else if ( newlevel > level.get(v) ){ |
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| 313 | newlevel = level.get(v); |
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| 314 | } |
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| 315 | |
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| 316 | } //for out edges wv |
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| 317 | |
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| 318 | |
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| 319 | if ( exc > 0 ) { |
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| 320 | for( InEdgeIt e=G.template first<InEdgeIt>(w); e.valid(); ++e) { |
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| 321 | |
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| 322 | if( _flow.get(e) == 0 ) continue; |
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| 323 | NodeIt v=G.tail(e); |
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| 324 | //e=vw |
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| 325 | |
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| 326 | if( lev > level.get(v) ) { |
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| 327 | /*Push is allowed now*/ |
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| 328 | |
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| 329 | if ( excess.get(v)==0 && v!=t && v!=s ) { |
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| 330 | int lev_v=level.get(v); |
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| 331 | next.set(v,active[lev_v]); |
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| 332 | active[lev_v]=v; |
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| 333 | } |
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| 334 | |
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| 335 | T flo=_flow.get(e); |
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| 336 | |
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| 337 | if ( flo >= exc ) { |
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| 338 | /*A nonsaturating push.*/ |
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| 339 | |
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| 340 | _flow.set(e, flo-exc); |
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| 341 | excess.set(v, excess.get(v)+exc); |
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| 342 | exc=0; |
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| 343 | break; |
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| 344 | } else { |
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| 345 | /*A saturating push.*/ |
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| 346 | |
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| 347 | excess.set(v, excess.get(v)+flo); |
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| 348 | exc-=flo; |
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| 349 | _flow.set(e,0); |
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| 350 | } |
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| 351 | } else if ( newlevel > level.get(v) ) { |
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| 352 | newlevel = level.get(v); |
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| 353 | } |
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| 354 | } //for in edges vw |
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| 355 | |
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| 356 | } // if w still has excess after the out edge for cycle |
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| 357 | |
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| 358 | excess.set(w, exc); |
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| 359 | |
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| 360 | /* |
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| 361 | Relabel |
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| 362 | */ |
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| 363 | |
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| 364 | |
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| 365 | if ( exc > 0 ) { |
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| 366 | //now 'lev' is the old level of w |
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| 367 | |
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| 368 | if ( phase ) { |
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| 369 | level.set(w,++newlevel); |
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| 370 | next.set(w,active[newlevel]); |
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| 371 | active[newlevel]=w; |
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| 372 | b=newlevel; |
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| 373 | } else { |
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| 374 | //unlacing starts |
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| 375 | NodeIt right_n=right.get(w); |
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| 376 | NodeIt left_n=left.get(w); |
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| 377 | |
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| 378 | if ( right_n != 0 ) { |
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| 379 | if ( left_n != 0 ) { |
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| 380 | right.set(left_n, right_n); |
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| 381 | left.set(right_n, left_n); |
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| 382 | } else { |
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| 383 | level_list[lev]=right_n; |
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| 384 | left.set(right_n, 0); |
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| 385 | } |
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| 386 | } else { |
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| 387 | if ( left_n != 0 ) { |
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| 388 | right.set(left_n, 0); |
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| 389 | } else { |
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| 390 | level_list[lev]=0; |
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| 391 | |
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| 392 | } |
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| 393 | } |
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| 394 | //unlacing ends |
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| 395 | |
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| 396 | //gapping starts |
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| 397 | if ( level_list[lev]==0 ) { |
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| 398 | |
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| 399 | for (int i=lev; i!=k ; ) { |
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| 400 | NodeIt v=level_list[++i]; |
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| 401 | while ( v != 0 ) { |
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| 402 | level.set(v,n); |
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| 403 | v=right.get(v); |
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| 404 | } |
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| 405 | level_list[i]=0; |
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| 406 | if ( !what_heur ) active[i]=0; |
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| 407 | } |
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| 408 | |
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| 409 | level.set(w,n); |
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| 410 | b=lev-1; |
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| 411 | k=b; |
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| 412 | //gapping ends |
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| 413 | } else { |
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| 414 | |
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| 415 | if ( newlevel == n ) level.set(w,n); |
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| 416 | else { |
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| 417 | level.set(w,++newlevel); |
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| 418 | next.set(w,active[newlevel]); |
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| 419 | active[newlevel]=w; |
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| 420 | if ( what_heur ) b=newlevel; |
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| 421 | if ( k < newlevel ) ++k; |
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| 422 | NodeIt first=level_list[newlevel]; |
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| 423 | if ( first != 0 ) left.set(first,w); |
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| 424 | right.set(w,first); |
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| 425 | left.set(w,0); |
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| 426 | level_list[newlevel]=w; |
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| 427 | } |
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| 428 | } |
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| 429 | |
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| 430 | |
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| 431 | ++relabel; |
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| 432 | if ( relabel >= heur ) { |
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| 433 | relabel=0; |
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| 434 | if ( what_heur ) { |
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| 435 | what_heur=0; |
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| 436 | heur=heur0; |
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| 437 | end=false; |
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| 438 | } else { |
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| 439 | what_heur=1; |
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| 440 | heur=heur1; |
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| 441 | b=k; |
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| 442 | } |
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| 443 | } |
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| 444 | } //phase 0 |
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| 445 | |
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| 446 | |
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| 447 | } // if ( exc > 0 ) |
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| 448 | |
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| 449 | |
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| 450 | } // if stack[b] is nonempty |
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| 451 | |
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| 452 | } // while(true) |
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| 453 | |
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| 454 | |
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| 455 | value = excess.get(t); |
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| 456 | /*Max flow value.*/ |
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| 457 | |
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| 458 | } //void run() |
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| 459 | |
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| 460 | |
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| 461 | |
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| 462 | |
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| 463 | |
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| 464 | /* |
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| 465 | Returns the maximum value of a flow. |
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| 466 | */ |
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| 467 | |
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| 468 | T maxFlow() { |
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| 469 | return value; |
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| 470 | } |
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| 471 | |
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| 472 | |
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| 473 | |
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| 474 | /* |
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| 475 | For the maximum flow x found by the algorithm, |
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| 476 | it returns the flow value on edge e, i.e. x(e). |
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| 477 | */ |
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| 478 | |
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| 479 | T flow(EdgeIt e) { |
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| 480 | return _flow.get(e); |
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| 481 | } |
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| 482 | |
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| 483 | |
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| 484 | |
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| 485 | FlowMap flow() { |
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| 486 | return _flow; |
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| 487 | } |
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| 488 | |
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| 489 | |
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| 490 | |
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| 491 | void flow(FlowMap& __flow ) { |
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| 492 | for(EachNodeIt v=G.template first<EachNodeIt>(); v.valid(); ++v) |
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| 493 | __flow.set(v,_flow.get(v)); |
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| 494 | } |
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| 495 | |
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| 496 | |
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| 497 | |
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| 498 | /* |
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| 499 | Returns the minimum min cut, by a bfs from s in the residual graph. |
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| 500 | */ |
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| 501 | |
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| 502 | template<typename _CutMap> |
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| 503 | void minMinCut(_CutMap& M) { |
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| 504 | |
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| 505 | std::queue<NodeIt> queue; |
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| 506 | |
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| 507 | M.set(s,true); |
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| 508 | queue.push(s); |
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| 509 | |
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| 510 | while (!queue.empty()) { |
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| 511 | NodeIt w=queue.front(); |
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| 512 | queue.pop(); |
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| 513 | |
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| 514 | for(OutEdgeIt e=G.template first<OutEdgeIt>(w) ; e.valid(); ++e) { |
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| 515 | NodeIt v=G.head(e); |
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| 516 | if (!M.get(v) && _flow.get(e) < capacity.get(e) ) { |
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| 517 | queue.push(v); |
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| 518 | M.set(v, true); |
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| 519 | } |
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| 520 | } |
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| 521 | |
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| 522 | for(InEdgeIt e=G.template first<InEdgeIt>(w) ; e.valid(); ++e) { |
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| 523 | NodeIt v=G.tail(e); |
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| 524 | if (!M.get(v) && _flow.get(e) > 0 ) { |
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| 525 | queue.push(v); |
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| 526 | M.set(v, true); |
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| 527 | } |
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| 528 | } |
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| 529 | } |
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| 530 | } |
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| 531 | |
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| 532 | |
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| 533 | |
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| 534 | /* |
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| 535 | Returns the maximum min cut, by a reverse bfs |
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| 536 | from t in the residual graph. |
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| 537 | */ |
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| 538 | |
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| 539 | template<typename _CutMap> |
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| 540 | void maxMinCut(_CutMap& M) { |
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| 541 | |
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| 542 | std::queue<NodeIt> queue; |
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| 543 | |
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| 544 | M.set(t,true); |
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| 545 | queue.push(t); |
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| 546 | |
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| 547 | while (!queue.empty()) { |
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| 548 | NodeIt w=queue.front(); |
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| 549 | queue.pop(); |
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| 550 | |
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| 551 | for(InEdgeIt e=G.template first<InEdgeIt>(w) ; e.valid(); ++e) { |
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| 552 | NodeIt v=G.tail(e); |
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| 553 | if (!M.get(v) && _flow.get(e) < capacity.get(e) ) { |
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| 554 | queue.push(v); |
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| 555 | M.set(v, true); |
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| 556 | } |
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| 557 | } |
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| 558 | |
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| 559 | for(OutEdgeIt e=G.template first<OutEdgeIt>(w) ; e.valid(); ++e) { |
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| 560 | NodeIt v=G.head(e); |
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| 561 | if (!M.get(v) && _flow.get(e) > 0 ) { |
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| 562 | queue.push(v); |
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| 563 | M.set(v, true); |
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| 564 | } |
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| 565 | } |
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| 566 | } |
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| 567 | |
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| 568 | for(EachNodeIt v=G.template first<EachNodeIt>() ; v.valid(); ++v) { |
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| 569 | M.set(v, !M.get(v)); |
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| 570 | } |
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| 571 | |
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| 572 | } |
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| 573 | |
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| 574 | |
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| 575 | |
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| 576 | template<typename CutMap> |
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| 577 | void minCut(CutMap& M) { |
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| 578 | minMinCut(M); |
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| 579 | } |
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| 580 | |
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| 581 | |
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| 582 | }; |
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| 583 | }//namespace marci |
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| 584 | #endif |
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| 585 | |
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| 586 | |
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| 587 | |
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| 588 | |
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