[59] | 1 | #ifndef EDMONDS_KARP_HH |
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| 2 | #define EDMONDS_KARP_HH |
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[43] | 3 | |
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| 4 | #include <algorithm> |
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| 5 | |
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| 6 | #include <bfs_iterator.hh> |
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| 7 | |
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| 8 | namespace marci { |
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| 9 | |
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[59] | 10 | template<typename Graph, typename T, typename FlowMap, typename CapacityMap> |
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[43] | 11 | class ResGraph { |
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| 12 | typedef typename Graph::NodeIt NodeIt; |
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| 13 | typedef typename Graph::EachNodeIt EachNodeIt; |
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| 14 | typedef typename Graph::SymEdgeIt OldSymEdgeIt; |
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| 15 | const Graph& G; |
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[59] | 16 | FlowMap& flow; |
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| 17 | const CapacityMap& capacity; |
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[43] | 18 | public: |
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[59] | 19 | ResGraph(const Graph& _G, FlowMap& _flow, |
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| 20 | const CapacityMap& _capacity) : |
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[43] | 21 | G(_G), flow(_flow), capacity(_capacity) { } |
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| 22 | |
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| 23 | class EdgeIt; |
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| 24 | class OutEdgeIt; |
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| 25 | friend class EdgeIt; |
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| 26 | friend class OutEdgeIt; |
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| 27 | |
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| 28 | class EdgeIt { |
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[59] | 29 | friend class ResGraph<Graph, T, FlowMap, CapacityMap>; |
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[43] | 30 | protected: |
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[59] | 31 | const ResGraph<Graph, T, FlowMap, CapacityMap>* resG; |
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[43] | 32 | OldSymEdgeIt sym; |
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| 33 | public: |
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| 34 | EdgeIt() { } |
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| 35 | //EdgeIt(const EdgeIt& e) : resG(e.resG), sym(e.sym) { } |
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| 36 | T free() const { |
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| 37 | if (resG->G.aNode(sym)==resG->G.tail(sym)) { |
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| 38 | return (resG->capacity.get(sym)-resG->flow.get(sym)); |
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| 39 | } else { |
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| 40 | return (resG->flow.get(sym)); |
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| 41 | } |
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| 42 | } |
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| 43 | bool valid() const { return sym.valid(); } |
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[64] | 44 | void augment(T a) const { |
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[43] | 45 | if (resG->G.aNode(sym)==resG->G.tail(sym)) { |
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| 46 | resG->flow.set(sym, resG->flow.get(sym)+a); |
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| 47 | } else { |
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| 48 | resG->flow.set(sym, resG->flow.get(sym)-a); |
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| 49 | } |
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| 50 | } |
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| 51 | }; |
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| 52 | |
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| 53 | class OutEdgeIt : public EdgeIt { |
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[59] | 54 | friend class ResGraph<Graph, T, FlowMap, CapacityMap>; |
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[43] | 55 | public: |
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| 56 | OutEdgeIt() { } |
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| 57 | //OutEdgeIt(const OutEdgeIt& e) { resG=e.resG; sym=e.sym; } |
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| 58 | private: |
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[64] | 59 | OutEdgeIt(const ResGraph<Graph, T, FlowMap, CapacityMap>& _resG, NodeIt v) { |
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[43] | 60 | resG=&_resG; |
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| 61 | sym=resG->G.template first<OldSymEdgeIt>(v); |
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| 62 | while( sym.valid() && !(free()>0) ) { ++sym; } |
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| 63 | } |
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| 64 | public: |
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| 65 | OutEdgeIt& operator++() { |
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| 66 | ++sym; |
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| 67 | while( sym.valid() && !(free()>0) ) { ++sym; } |
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| 68 | return *this; |
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| 69 | } |
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| 70 | }; |
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| 71 | |
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[64] | 72 | void getFirst(OutEdgeIt& e, NodeIt v) const { |
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[43] | 73 | e=OutEdgeIt(*this, v); |
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| 74 | } |
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| 75 | void getFirst(EachNodeIt& v) const { G.getFirst(v); } |
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| 76 | |
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| 77 | template< typename It > |
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| 78 | It first() const { |
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| 79 | It e; |
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| 80 | getFirst(e); |
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| 81 | return e; |
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| 82 | } |
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| 83 | |
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| 84 | template< typename It > |
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[64] | 85 | It first(NodeIt v) const { |
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[43] | 86 | It e; |
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| 87 | getFirst(e, v); |
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| 88 | return e; |
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| 89 | } |
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| 90 | |
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[64] | 91 | NodeIt tail(EdgeIt e) const { return G.aNode(e.sym); } |
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| 92 | NodeIt head(EdgeIt e) const { return G.bNode(e.sym); } |
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[43] | 93 | |
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[64] | 94 | NodeIt aNode(OutEdgeIt e) const { return G.aNode(e.sym); } |
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| 95 | NodeIt bNode(OutEdgeIt e) const { return G.bNode(e.sym); } |
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[43] | 96 | |
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[64] | 97 | int id(NodeIt v) const { return G.id(v); } |
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[43] | 98 | |
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[69] | 99 | template <typename S> |
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[43] | 100 | class NodeMap { |
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[69] | 101 | typename Graph::NodeMap<S> node_map; |
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[43] | 102 | public: |
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[59] | 103 | NodeMap(const ResGraph<Graph, T, FlowMap, CapacityMap>& _G) : node_map(_G.G) { } |
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[69] | 104 | NodeMap(const ResGraph<Graph, T, FlowMap, CapacityMap>& _G, S a) : node_map(_G.G, a) { } |
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| 105 | void set(NodeIt nit, S a) { node_map.set(nit, a); } |
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| 106 | S get(NodeIt nit) const { return node_map.get(nit); } |
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[43] | 107 | }; |
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| 108 | |
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| 109 | }; |
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| 110 | |
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[59] | 111 | template <typename Graph, typename T, typename FlowMap, typename CapacityMap> |
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| 112 | class MaxFlow { |
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[43] | 113 | typedef typename Graph::NodeIt NodeIt; |
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| 114 | typedef typename Graph::EdgeIt EdgeIt; |
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| 115 | typedef typename Graph::EachEdgeIt EachEdgeIt; |
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| 116 | typedef typename Graph::OutEdgeIt OutEdgeIt; |
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| 117 | typedef typename Graph::InEdgeIt InEdgeIt; |
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| 118 | const Graph& G; |
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[64] | 119 | NodeIt s; |
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| 120 | NodeIt t; |
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[59] | 121 | FlowMap& flow; |
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| 122 | const CapacityMap& capacity; |
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| 123 | typedef ResGraph<Graph, T, FlowMap, CapacityMap > AugGraph; |
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| 124 | typedef typename AugGraph::OutEdgeIt AugOutEdgeIt; |
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| 125 | typedef typename AugGraph::EdgeIt AugEdgeIt; |
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| 126 | public: |
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[64] | 127 | MaxFlow(const Graph& _G, NodeIt _s, NodeIt _t, FlowMap& _flow, const CapacityMap& _capacity) : G(_G), s(_s), t(_t), flow(_flow), capacity(_capacity) { } |
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[59] | 128 | bool augment() { |
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| 129 | AugGraph res_graph(G, flow, capacity); |
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| 130 | bool _augment=false; |
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| 131 | |
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| 132 | typedef typename AugGraph::NodeMap<bool> ReachedMap; |
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| 133 | BfsIterator2< AugGraph, AugOutEdgeIt, ReachedMap > res_bfs(res_graph); |
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| 134 | res_bfs.pushAndSetReached(s); |
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| 135 | |
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| 136 | typename AugGraph::NodeMap<AugEdgeIt> pred(res_graph); |
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| 137 | //filled with invalid iterators |
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| 138 | |
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| 139 | typename AugGraph::NodeMap<int> free(res_graph); |
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| 140 | |
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| 141 | //searching for augmenting path |
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| 142 | while ( !res_bfs.finished() ) { |
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| 143 | AugOutEdgeIt e=AugOutEdgeIt(res_bfs); |
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| 144 | if (e.valid() && res_bfs.isBNodeNewlyReached()) { |
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| 145 | NodeIt v=res_graph.tail(e); |
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| 146 | NodeIt w=res_graph.head(e); |
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| 147 | pred.set(w, e); |
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| 148 | if (pred.get(v).valid()) { |
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| 149 | free.set(w, std::min(free.get(v), e.free())); |
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| 150 | } else { |
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| 151 | free.set(w, e.free()); |
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| 152 | } |
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| 153 | if (res_graph.head(e)==t) { _augment=true; break; } |
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| 154 | } |
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| 155 | |
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| 156 | ++res_bfs; |
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| 157 | } //end of searching augmenting path |
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[43] | 158 | |
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[59] | 159 | if (_augment) { |
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| 160 | NodeIt n=t; |
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| 161 | T augment_value=free.get(t); |
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| 162 | while (pred.get(n).valid()) { |
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| 163 | AugEdgeIt e=pred.get(n); |
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| 164 | e.augment(augment_value); |
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| 165 | n=res_graph.tail(e); |
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| 166 | } |
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| 167 | } |
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| 168 | |
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| 169 | return _augment; |
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| 170 | } |
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[43] | 171 | void run() { |
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[59] | 172 | while (augment()) { } |
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[43] | 173 | } |
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[69] | 174 | T flowValue() { |
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| 175 | T a=0; |
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| 176 | for(OutEdgeIt i=G.template first<OutEdgeIt>(s); i.valid(); ++i) { |
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| 177 | a+=flow.get(i); |
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| 178 | } |
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| 179 | return a; |
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| 180 | } |
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[43] | 181 | }; |
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| 182 | |
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| 183 | } // namespace marci |
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| 184 | |
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[59] | 185 | #endif //EDMONDS_KARP_HH |
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