[109] | 1 | // -*- C++ -*- |
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[372] | 2 | |
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[109] | 3 | /* |
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| 4 | Heuristics: |
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| 5 | 2 phase |
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| 6 | gap |
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| 7 | list 'level_list' on the nodes on level i implemented by hand |
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[451] | 8 | stack 'active' on the active nodes on level i |
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[109] | 9 | runs heuristic 'highest label' for H1*n relabels |
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[113] | 10 | runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label' |
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[109] | 11 | |
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[451] | 12 | Parameters H0 and H1 are initialized to 20 and 1. |
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[109] | 13 | |
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[211] | 14 | Constructors: |
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[109] | 15 | |
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[372] | 16 | Preflow(Graph, Node, Node, CapMap, FlowMap, bool) : bool must be false if |
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| 17 | FlowMap is not constant zero, and should be true if it is |
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[109] | 18 | |
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| 19 | Members: |
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| 20 | |
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[211] | 21 | void run() |
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[109] | 22 | |
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[468] | 23 | Num flowValue() : returns the value of a maximum flow |
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[109] | 24 | |
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| 25 | void minMinCut(CutMap& M) : sets M to the characteristic vector of the |
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[451] | 26 | minimum min cut. M should be a map of bools initialized to false. ??Is it OK? |
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[109] | 27 | |
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| 28 | void maxMinCut(CutMap& M) : sets M to the characteristic vector of the |
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| 29 | maximum min cut. M should be a map of bools initialized to false. |
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| 30 | |
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| 31 | void minCut(CutMap& M) : sets M to the characteristic vector of |
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| 32 | a min cut. M should be a map of bools initialized to false. |
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| 33 | |
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| 34 | */ |
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| 35 | |
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[211] | 36 | #ifndef HUGO_PREFLOW_H |
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| 37 | #define HUGO_PREFLOW_H |
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[109] | 38 | |
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| 39 | #define H0 20 |
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| 40 | #define H1 1 |
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| 41 | |
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| 42 | #include <vector> |
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| 43 | #include <queue> |
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[451] | 44 | #include <stack> |
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[109] | 45 | |
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[471] | 46 | #include <graph_wrapper.h> |
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[472] | 47 | #include <bfs_iterator.h> |
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| 48 | #include <invalid.h> |
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| 49 | #include <maps.h> |
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| 50 | #include <for_each_macros.h> |
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| 51 | |
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[471] | 52 | |
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[109] | 53 | namespace hugo { |
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| 54 | |
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[468] | 55 | template <typename Graph, typename Num, |
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| 56 | typename CapMap=typename Graph::template EdgeMap<Num>, |
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| 57 | typename FlowMap=typename Graph::template EdgeMap<Num> > |
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[476] | 58 | class MaxFlow { |
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[109] | 59 | |
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[211] | 60 | typedef typename Graph::Node Node; |
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[109] | 61 | typedef typename Graph::NodeIt NodeIt; |
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| 62 | typedef typename Graph::OutEdgeIt OutEdgeIt; |
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| 63 | typedef typename Graph::InEdgeIt InEdgeIt; |
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[451] | 64 | |
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| 65 | typedef typename std::vector<std::stack<Node> > VecStack; |
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| 66 | typedef typename Graph::template NodeMap<Node> NNMap; |
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| 67 | typedef typename std::vector<Node> VecNode; |
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| 68 | |
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[466] | 69 | const Graph* g; |
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[211] | 70 | Node s; |
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| 71 | Node t; |
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[465] | 72 | const CapMap* capacity; |
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[451] | 73 | FlowMap* flow; |
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| 74 | int n; //the number of nodes of G |
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[471] | 75 | typedef ResGraphWrapper<const Graph, Num, CapMap, FlowMap> ResGW; |
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| 76 | typedef typename ResGW::OutEdgeIt ResGWOutEdgeIt; |
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| 77 | typedef typename ResGW::Edge ResGWEdge; |
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| 78 | //typedef typename ResGW::template NodeMap<bool> ReachedMap; |
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| 79 | typedef typename Graph::template NodeMap<int> ReachedMap; |
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| 80 | ReachedMap level; |
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| 81 | //level works as a bool map in augmenting path algorithms |
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| 82 | //and is used by bfs for storing reached information. |
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| 83 | //In preflow, it shows levels of nodes. |
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| 84 | //typename Graph::template NodeMap<int> level; |
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[468] | 85 | typename Graph::template NodeMap<Num> excess; |
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[451] | 86 | |
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[109] | 87 | public: |
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[451] | 88 | |
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| 89 | enum flowEnum{ |
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| 90 | ZERO_FLOW=0, |
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| 91 | GEN_FLOW=1, |
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| 92 | PREFLOW=2 |
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| 93 | }; |
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| 94 | |
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[476] | 95 | MaxFlow(const Graph& _G, Node _s, Node _t, const CapMap& _capacity, |
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[451] | 96 | FlowMap& _flow) : |
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[466] | 97 | g(&_G), s(_s), t(_t), capacity(&_capacity), |
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[451] | 98 | flow(&_flow), n(_G.nodeNum()), level(_G), excess(_G,0) {} |
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| 99 | |
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| 100 | void run() { |
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| 101 | preflow( ZERO_FLOW ); |
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| 102 | } |
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[372] | 103 | |
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[451] | 104 | void preflow( flowEnum fe ) { |
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| 105 | preflowPhase0(fe); |
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| 106 | preflowPhase1(); |
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| 107 | } |
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| 108 | |
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[471] | 109 | void preflowPhase0( flowEnum fe ); |
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[451] | 110 | |
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[471] | 111 | void preflowPhase1(); |
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[451] | 112 | |
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[471] | 113 | bool augmentOnShortestPath(); |
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[109] | 114 | |
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[471] | 115 | template<typename MutableGraph> bool augmentOnBlockingFlow(); |
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[451] | 116 | |
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[471] | 117 | bool augmentOnBlockingFlow2(); |
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[109] | 118 | |
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[472] | 119 | /// Returns the actual flow value. |
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| 120 | /// More precisely, it returns the negative excess of s, thus |
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| 121 | /// this works also for preflows. |
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| 122 | Num flowValue() { |
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| 123 | Num a=0; |
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| 124 | FOR_EACH_INC_LOC(OutEdgeIt, e, *g, s) a+=(*flow)[e]; |
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| 125 | FOR_EACH_INC_LOC(InEdgeIt, e, *g, s) a-=(*flow)[e]; |
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| 126 | return a; |
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[451] | 127 | } |
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[109] | 128 | |
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[451] | 129 | //should be used only between preflowPhase0 and preflowPhase1 |
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| 130 | template<typename _CutMap> |
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| 131 | void actMinCut(_CutMap& M) { |
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[211] | 132 | NodeIt v; |
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[466] | 133 | for(g->first(v); g->valid(v); g->next(v)) |
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| 134 | if ( level[v] < n ) { |
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| 135 | M.set(v,false); |
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| 136 | } else { |
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| 137 | M.set(v,true); |
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| 138 | } |
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[211] | 139 | } |
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[109] | 140 | |
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| 141 | |
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| 142 | |
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| 143 | /* |
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| 144 | Returns the minimum min cut, by a bfs from s in the residual graph. |
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| 145 | */ |
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| 146 | template<typename _CutMap> |
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| 147 | void minMinCut(_CutMap& M) { |
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| 148 | |
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[211] | 149 | std::queue<Node> queue; |
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[109] | 150 | |
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| 151 | M.set(s,true); |
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| 152 | queue.push(s); |
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| 153 | |
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| 154 | while (!queue.empty()) { |
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[211] | 155 | Node w=queue.front(); |
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[109] | 156 | queue.pop(); |
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| 157 | |
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[211] | 158 | OutEdgeIt e; |
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[466] | 159 | for(g->first(e,w) ; g->valid(e); g->next(e)) { |
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| 160 | Node v=g->head(e); |
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[451] | 161 | if (!M[v] && (*flow)[e] < (*capacity)[e] ) { |
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[109] | 162 | queue.push(v); |
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| 163 | M.set(v, true); |
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| 164 | } |
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| 165 | } |
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| 166 | |
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[211] | 167 | InEdgeIt f; |
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[466] | 168 | for(g->first(f,w) ; g->valid(f); g->next(f)) { |
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| 169 | Node v=g->tail(f); |
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[451] | 170 | if (!M[v] && (*flow)[f] > 0 ) { |
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[109] | 171 | queue.push(v); |
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| 172 | M.set(v, true); |
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| 173 | } |
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| 174 | } |
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| 175 | } |
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| 176 | } |
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| 177 | |
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| 178 | |
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| 179 | |
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| 180 | /* |
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| 181 | Returns the maximum min cut, by a reverse bfs |
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| 182 | from t in the residual graph. |
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| 183 | */ |
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| 184 | |
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| 185 | template<typename _CutMap> |
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| 186 | void maxMinCut(_CutMap& M) { |
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[451] | 187 | |
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| 188 | NodeIt v; |
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[466] | 189 | for(g->first(v) ; g->valid(v); g->next(v)) { |
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[451] | 190 | M.set(v, true); |
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| 191 | } |
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| 192 | |
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[211] | 193 | std::queue<Node> queue; |
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[109] | 194 | |
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[451] | 195 | M.set(t,false); |
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[109] | 196 | queue.push(t); |
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| 197 | |
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| 198 | while (!queue.empty()) { |
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[211] | 199 | Node w=queue.front(); |
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[109] | 200 | queue.pop(); |
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| 201 | |
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[211] | 202 | |
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| 203 | InEdgeIt e; |
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[466] | 204 | for(g->first(e,w) ; g->valid(e); g->next(e)) { |
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| 205 | Node v=g->tail(e); |
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[451] | 206 | if (M[v] && (*flow)[e] < (*capacity)[e] ) { |
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[109] | 207 | queue.push(v); |
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[451] | 208 | M.set(v, false); |
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[109] | 209 | } |
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| 210 | } |
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[211] | 211 | |
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| 212 | OutEdgeIt f; |
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[466] | 213 | for(g->first(f,w) ; g->valid(f); g->next(f)) { |
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| 214 | Node v=g->head(f); |
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[451] | 215 | if (M[v] && (*flow)[f] > 0 ) { |
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[109] | 216 | queue.push(v); |
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[451] | 217 | M.set(v, false); |
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[109] | 218 | } |
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| 219 | } |
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| 220 | } |
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| 221 | } |
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| 222 | |
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| 223 | |
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| 224 | template<typename CutMap> |
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| 225 | void minCut(CutMap& M) { |
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| 226 | minMinCut(M); |
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| 227 | } |
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| 228 | |
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[468] | 229 | void resetTarget(Node _t) {t=_t;} |
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| 230 | void resetSource(Node _s) {s=_s;} |
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[372] | 231 | |
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[468] | 232 | void resetCap(const CapMap& _cap) { |
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[451] | 233 | capacity=&_cap; |
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| 234 | } |
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| 235 | |
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[468] | 236 | void resetFlow(FlowMap& _flow) { |
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[451] | 237 | flow=&_flow; |
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[372] | 238 | } |
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| 239 | |
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| 240 | |
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[451] | 241 | private: |
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| 242 | |
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[469] | 243 | int push(Node w, VecStack& active) { |
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[451] | 244 | |
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| 245 | int lev=level[w]; |
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[468] | 246 | Num exc=excess[w]; |
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[451] | 247 | int newlevel=n; //bound on the next level of w |
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| 248 | |
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| 249 | OutEdgeIt e; |
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[466] | 250 | for(g->first(e,w); g->valid(e); g->next(e)) { |
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[451] | 251 | |
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[470] | 252 | if ( (*flow)[e] >= (*capacity)[e] ) continue; |
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[466] | 253 | Node v=g->head(e); |
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[451] | 254 | |
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| 255 | if( lev > level[v] ) { //Push is allowed now |
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| 256 | |
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[470] | 257 | if ( excess[v]<=0 && v!=t && v!=s ) { |
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[451] | 258 | int lev_v=level[v]; |
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| 259 | active[lev_v].push(v); |
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| 260 | } |
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| 261 | |
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[468] | 262 | Num cap=(*capacity)[e]; |
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| 263 | Num flo=(*flow)[e]; |
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| 264 | Num remcap=cap-flo; |
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[451] | 265 | |
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| 266 | if ( remcap >= exc ) { //A nonsaturating push. |
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| 267 | |
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| 268 | flow->set(e, flo+exc); |
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| 269 | excess.set(v, excess[v]+exc); |
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| 270 | exc=0; |
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| 271 | break; |
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| 272 | |
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| 273 | } else { //A saturating push. |
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| 274 | flow->set(e, cap); |
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| 275 | excess.set(v, excess[v]+remcap); |
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| 276 | exc-=remcap; |
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| 277 | } |
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| 278 | } else if ( newlevel > level[v] ) newlevel = level[v]; |
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| 279 | } //for out edges wv |
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| 280 | |
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| 281 | if ( exc > 0 ) { |
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| 282 | InEdgeIt e; |
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[466] | 283 | for(g->first(e,w); g->valid(e); g->next(e)) { |
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[451] | 284 | |
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[470] | 285 | if( (*flow)[e] <= 0 ) continue; |
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[466] | 286 | Node v=g->tail(e); |
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[451] | 287 | |
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| 288 | if( lev > level[v] ) { //Push is allowed now |
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| 289 | |
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[470] | 290 | if ( excess[v]<=0 && v!=t && v!=s ) { |
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[451] | 291 | int lev_v=level[v]; |
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| 292 | active[lev_v].push(v); |
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| 293 | } |
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| 294 | |
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[468] | 295 | Num flo=(*flow)[e]; |
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[451] | 296 | |
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| 297 | if ( flo >= exc ) { //A nonsaturating push. |
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| 298 | |
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| 299 | flow->set(e, flo-exc); |
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| 300 | excess.set(v, excess[v]+exc); |
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| 301 | exc=0; |
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| 302 | break; |
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| 303 | } else { //A saturating push. |
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| 304 | |
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| 305 | excess.set(v, excess[v]+flo); |
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| 306 | exc-=flo; |
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| 307 | flow->set(e,0); |
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| 308 | } |
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| 309 | } else if ( newlevel > level[v] ) newlevel = level[v]; |
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| 310 | } //for in edges vw |
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| 311 | |
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| 312 | } // if w still has excess after the out edge for cycle |
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| 313 | |
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| 314 | excess.set(w, exc); |
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| 315 | |
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| 316 | return newlevel; |
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| 317 | } |
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| 318 | |
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| 319 | |
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| 320 | void preflowPreproc ( flowEnum fe, VecStack& active, |
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| 321 | VecNode& level_list, NNMap& left, NNMap& right ) { |
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| 322 | |
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| 323 | std::queue<Node> bfs_queue; |
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| 324 | |
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| 325 | switch ( fe ) { |
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| 326 | case ZERO_FLOW: |
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| 327 | { |
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| 328 | //Reverse_bfs from t, to find the starting level. |
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| 329 | level.set(t,0); |
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| 330 | bfs_queue.push(t); |
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| 331 | |
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| 332 | while (!bfs_queue.empty()) { |
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| 333 | |
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| 334 | Node v=bfs_queue.front(); |
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| 335 | bfs_queue.pop(); |
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| 336 | int l=level[v]+1; |
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| 337 | |
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| 338 | InEdgeIt e; |
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[466] | 339 | for(g->first(e,v); g->valid(e); g->next(e)) { |
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| 340 | Node w=g->tail(e); |
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[451] | 341 | if ( level[w] == n && w != s ) { |
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| 342 | bfs_queue.push(w); |
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| 343 | Node first=level_list[l]; |
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[466] | 344 | if ( g->valid(first) ) left.set(first,w); |
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[451] | 345 | right.set(w,first); |
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| 346 | level_list[l]=w; |
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| 347 | level.set(w, l); |
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| 348 | } |
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| 349 | } |
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| 350 | } |
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| 351 | |
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| 352 | //the starting flow |
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| 353 | OutEdgeIt e; |
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[466] | 354 | for(g->first(e,s); g->valid(e); g->next(e)) |
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[451] | 355 | { |
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[468] | 356 | Num c=(*capacity)[e]; |
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[470] | 357 | if ( c <= 0 ) continue; |
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[466] | 358 | Node w=g->head(e); |
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[451] | 359 | if ( level[w] < n ) { |
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[470] | 360 | if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w); |
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[451] | 361 | flow->set(e, c); |
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| 362 | excess.set(w, excess[w]+c); |
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| 363 | } |
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| 364 | } |
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| 365 | break; |
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| 366 | } |
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| 367 | |
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| 368 | case GEN_FLOW: |
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| 369 | case PREFLOW: |
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| 370 | { |
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| 371 | //Reverse_bfs from t in the residual graph, |
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| 372 | //to find the starting level. |
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| 373 | level.set(t,0); |
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| 374 | bfs_queue.push(t); |
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| 375 | |
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| 376 | while (!bfs_queue.empty()) { |
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| 377 | |
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| 378 | Node v=bfs_queue.front(); |
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| 379 | bfs_queue.pop(); |
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| 380 | int l=level[v]+1; |
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| 381 | |
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| 382 | InEdgeIt e; |
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[466] | 383 | for(g->first(e,v); g->valid(e); g->next(e)) { |
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[470] | 384 | if ( (*capacity)[e] <= (*flow)[e] ) continue; |
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[466] | 385 | Node w=g->tail(e); |
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[451] | 386 | if ( level[w] == n && w != s ) { |
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| 387 | bfs_queue.push(w); |
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| 388 | Node first=level_list[l]; |
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[466] | 389 | if ( g->valid(first) ) left.set(first,w); |
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[451] | 390 | right.set(w,first); |
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| 391 | level_list[l]=w; |
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| 392 | level.set(w, l); |
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| 393 | } |
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| 394 | } |
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| 395 | |
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| 396 | OutEdgeIt f; |
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[466] | 397 | for(g->first(f,v); g->valid(f); g->next(f)) { |
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[470] | 398 | if ( 0 >= (*flow)[f] ) continue; |
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[466] | 399 | Node w=g->head(f); |
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[451] | 400 | if ( level[w] == n && w != s ) { |
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| 401 | bfs_queue.push(w); |
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| 402 | Node first=level_list[l]; |
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[466] | 403 | if ( g->valid(first) ) left.set(first,w); |
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[451] | 404 | right.set(w,first); |
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| 405 | level_list[l]=w; |
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| 406 | level.set(w, l); |
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| 407 | } |
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| 408 | } |
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| 409 | } |
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| 410 | |
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| 411 | |
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| 412 | //the starting flow |
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| 413 | OutEdgeIt e; |
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[466] | 414 | for(g->first(e,s); g->valid(e); g->next(e)) |
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[451] | 415 | { |
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[468] | 416 | Num rem=(*capacity)[e]-(*flow)[e]; |
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[470] | 417 | if ( rem <= 0 ) continue; |
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[466] | 418 | Node w=g->head(e); |
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[451] | 419 | if ( level[w] < n ) { |
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[470] | 420 | if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w); |
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[451] | 421 | flow->set(e, (*capacity)[e]); |
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| 422 | excess.set(w, excess[w]+rem); |
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| 423 | } |
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| 424 | } |
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| 425 | |
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| 426 | InEdgeIt f; |
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[466] | 427 | for(g->first(f,s); g->valid(f); g->next(f)) |
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[451] | 428 | { |
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[470] | 429 | if ( (*flow)[f] <= 0 ) continue; |
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[466] | 430 | Node w=g->tail(f); |
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[451] | 431 | if ( level[w] < n ) { |
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[470] | 432 | if ( excess[w] <= 0 && w!=t ) active[level[w]].push(w); |
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[451] | 433 | excess.set(w, excess[w]+(*flow)[f]); |
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| 434 | flow->set(f, 0); |
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| 435 | } |
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| 436 | } |
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| 437 | break; |
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| 438 | } //case PREFLOW |
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| 439 | } |
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| 440 | } //preflowPreproc |
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| 441 | |
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| 442 | |
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| 443 | |
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[469] | 444 | void relabel(Node w, int newlevel, VecStack& active, |
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| 445 | VecNode& level_list, NNMap& left, |
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[472] | 446 | NNMap& right, int& b, int& k, bool what_heur ) |
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| 447 | { |
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[451] | 448 | |
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[468] | 449 | Num lev=level[w]; |
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[451] | 450 | |
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| 451 | Node right_n=right[w]; |
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| 452 | Node left_n=left[w]; |
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| 453 | |
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| 454 | //unlacing starts |
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[466] | 455 | if ( g->valid(right_n) ) { |
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| 456 | if ( g->valid(left_n) ) { |
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[451] | 457 | right.set(left_n, right_n); |
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| 458 | left.set(right_n, left_n); |
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| 459 | } else { |
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| 460 | level_list[lev]=right_n; |
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| 461 | left.set(right_n, INVALID); |
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| 462 | } |
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| 463 | } else { |
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[466] | 464 | if ( g->valid(left_n) ) { |
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[451] | 465 | right.set(left_n, INVALID); |
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| 466 | } else { |
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| 467 | level_list[lev]=INVALID; |
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| 468 | } |
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| 469 | } |
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| 470 | //unlacing ends |
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| 471 | |
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[466] | 472 | if ( !g->valid(level_list[lev]) ) { |
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[451] | 473 | |
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| 474 | //gapping starts |
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| 475 | for (int i=lev; i!=k ; ) { |
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| 476 | Node v=level_list[++i]; |
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[466] | 477 | while ( g->valid(v) ) { |
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[451] | 478 | level.set(v,n); |
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| 479 | v=right[v]; |
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| 480 | } |
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| 481 | level_list[i]=INVALID; |
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| 482 | if ( !what_heur ) { |
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| 483 | while ( !active[i].empty() ) { |
---|
| 484 | active[i].pop(); //FIXME: ezt szebben kene |
---|
| 485 | } |
---|
| 486 | } |
---|
| 487 | } |
---|
| 488 | |
---|
| 489 | level.set(w,n); |
---|
| 490 | b=lev-1; |
---|
| 491 | k=b; |
---|
| 492 | //gapping ends |
---|
| 493 | |
---|
| 494 | } else { |
---|
| 495 | |
---|
| 496 | if ( newlevel == n ) level.set(w,n); |
---|
| 497 | else { |
---|
| 498 | level.set(w,++newlevel); |
---|
| 499 | active[newlevel].push(w); |
---|
| 500 | if ( what_heur ) b=newlevel; |
---|
| 501 | if ( k < newlevel ) ++k; //now k=newlevel |
---|
| 502 | Node first=level_list[newlevel]; |
---|
[466] | 503 | if ( g->valid(first) ) left.set(first,w); |
---|
[451] | 504 | right.set(w,first); |
---|
| 505 | left.set(w,INVALID); |
---|
| 506 | level_list[newlevel]=w; |
---|
| 507 | } |
---|
| 508 | } |
---|
| 509 | |
---|
| 510 | } //relabel |
---|
[472] | 511 | |
---|
| 512 | |
---|
| 513 | template<typename MapGraphWrapper> |
---|
| 514 | class DistanceMap { |
---|
| 515 | protected: |
---|
| 516 | const MapGraphWrapper* g; |
---|
| 517 | typename MapGraphWrapper::template NodeMap<int> dist; |
---|
| 518 | public: |
---|
| 519 | DistanceMap(MapGraphWrapper& _g) : g(&_g), dist(*g, g->nodeNum()) { } |
---|
| 520 | void set(const typename MapGraphWrapper::Node& n, int a) { |
---|
| 521 | dist.set(n, a); |
---|
| 522 | } |
---|
| 523 | int operator[](const typename MapGraphWrapper::Node& n) |
---|
| 524 | { return dist[n]; } |
---|
| 525 | // int get(const typename MapGraphWrapper::Node& n) const { |
---|
| 526 | // return dist[n]; } |
---|
| 527 | // bool get(const typename MapGraphWrapper::Edge& e) const { |
---|
| 528 | // return (dist.get(g->tail(e))<dist.get(g->head(e))); } |
---|
| 529 | bool operator[](const typename MapGraphWrapper::Edge& e) const { |
---|
| 530 | return (dist[g->tail(e)]<dist[g->head(e)]); |
---|
| 531 | } |
---|
| 532 | }; |
---|
[451] | 533 | |
---|
[471] | 534 | }; |
---|
[109] | 535 | |
---|
[471] | 536 | |
---|
| 537 | template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
---|
[476] | 538 | void MaxFlow<Graph, Num, CapMap, FlowMap>::preflowPhase0( flowEnum fe ) |
---|
[471] | 539 | { |
---|
| 540 | |
---|
| 541 | int heur0=(int)(H0*n); //time while running 'bound decrease' |
---|
| 542 | int heur1=(int)(H1*n); //time while running 'highest label' |
---|
| 543 | int heur=heur1; //starting time interval (#of relabels) |
---|
| 544 | int numrelabel=0; |
---|
| 545 | |
---|
| 546 | bool what_heur=1; |
---|
| 547 | //It is 0 in case 'bound decrease' and 1 in case 'highest label' |
---|
| 548 | |
---|
| 549 | bool end=false; |
---|
| 550 | //Needed for 'bound decrease', true means no active nodes are above bound b. |
---|
| 551 | |
---|
| 552 | int k=n-2; //bound on the highest level under n containing a node |
---|
| 553 | int b=k; //bound on the highest level under n of an active node |
---|
| 554 | |
---|
| 555 | VecStack active(n); |
---|
| 556 | |
---|
| 557 | NNMap left(*g, INVALID); |
---|
| 558 | NNMap right(*g, INVALID); |
---|
| 559 | VecNode level_list(n,INVALID); |
---|
| 560 | //List of the nodes in level i<n, set to n. |
---|
| 561 | |
---|
| 562 | NodeIt v; |
---|
| 563 | for(g->first(v); g->valid(v); g->next(v)) level.set(v,n); |
---|
| 564 | //setting each node to level n |
---|
| 565 | |
---|
| 566 | switch ( fe ) { |
---|
| 567 | case PREFLOW: |
---|
| 568 | { |
---|
| 569 | //counting the excess |
---|
| 570 | NodeIt v; |
---|
| 571 | for(g->first(v); g->valid(v); g->next(v)) { |
---|
| 572 | Num exc=0; |
---|
| 573 | |
---|
| 574 | InEdgeIt e; |
---|
| 575 | for(g->first(e,v); g->valid(e); g->next(e)) exc+=(*flow)[e]; |
---|
| 576 | OutEdgeIt f; |
---|
| 577 | for(g->first(f,v); g->valid(f); g->next(f)) exc-=(*flow)[f]; |
---|
| 578 | |
---|
| 579 | excess.set(v,exc); |
---|
| 580 | |
---|
| 581 | //putting the active nodes into the stack |
---|
| 582 | int lev=level[v]; |
---|
| 583 | if ( exc > 0 && lev < n && v != t ) active[lev].push(v); |
---|
| 584 | } |
---|
| 585 | break; |
---|
| 586 | } |
---|
| 587 | case GEN_FLOW: |
---|
| 588 | { |
---|
| 589 | //Counting the excess of t |
---|
| 590 | Num exc=0; |
---|
| 591 | |
---|
| 592 | InEdgeIt e; |
---|
| 593 | for(g->first(e,t); g->valid(e); g->next(e)) exc+=(*flow)[e]; |
---|
| 594 | OutEdgeIt f; |
---|
| 595 | for(g->first(f,t); g->valid(f); g->next(f)) exc-=(*flow)[f]; |
---|
| 596 | |
---|
| 597 | excess.set(t,exc); |
---|
| 598 | |
---|
| 599 | break; |
---|
| 600 | } |
---|
| 601 | default: |
---|
| 602 | break; |
---|
| 603 | } |
---|
| 604 | |
---|
| 605 | preflowPreproc( fe, active, level_list, left, right ); |
---|
| 606 | //End of preprocessing |
---|
| 607 | |
---|
| 608 | |
---|
| 609 | //Push/relabel on the highest level active nodes. |
---|
| 610 | while ( true ) { |
---|
| 611 | if ( b == 0 ) { |
---|
| 612 | if ( !what_heur && !end && k > 0 ) { |
---|
| 613 | b=k; |
---|
| 614 | end=true; |
---|
| 615 | } else break; |
---|
| 616 | } |
---|
| 617 | |
---|
| 618 | if ( active[b].empty() ) --b; |
---|
| 619 | else { |
---|
| 620 | end=false; |
---|
| 621 | Node w=active[b].top(); |
---|
| 622 | active[b].pop(); |
---|
| 623 | int newlevel=push(w,active); |
---|
| 624 | if ( excess[w] > 0 ) relabel(w, newlevel, active, level_list, |
---|
| 625 | left, right, b, k, what_heur); |
---|
| 626 | |
---|
| 627 | ++numrelabel; |
---|
| 628 | if ( numrelabel >= heur ) { |
---|
| 629 | numrelabel=0; |
---|
| 630 | if ( what_heur ) { |
---|
| 631 | what_heur=0; |
---|
| 632 | heur=heur0; |
---|
| 633 | end=false; |
---|
| 634 | } else { |
---|
| 635 | what_heur=1; |
---|
| 636 | heur=heur1; |
---|
| 637 | b=k; |
---|
| 638 | } |
---|
| 639 | } |
---|
| 640 | } |
---|
| 641 | } |
---|
| 642 | } |
---|
| 643 | |
---|
| 644 | |
---|
| 645 | |
---|
| 646 | template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
---|
[476] | 647 | void MaxFlow<Graph, Num, CapMap, FlowMap>::preflowPhase1() |
---|
[471] | 648 | { |
---|
| 649 | |
---|
| 650 | int k=n-2; //bound on the highest level under n containing a node |
---|
| 651 | int b=k; //bound on the highest level under n of an active node |
---|
| 652 | |
---|
| 653 | VecStack active(n); |
---|
| 654 | level.set(s,0); |
---|
| 655 | std::queue<Node> bfs_queue; |
---|
| 656 | bfs_queue.push(s); |
---|
| 657 | |
---|
| 658 | while (!bfs_queue.empty()) { |
---|
| 659 | |
---|
| 660 | Node v=bfs_queue.front(); |
---|
| 661 | bfs_queue.pop(); |
---|
| 662 | int l=level[v]+1; |
---|
| 663 | |
---|
| 664 | InEdgeIt e; |
---|
| 665 | for(g->first(e,v); g->valid(e); g->next(e)) { |
---|
| 666 | if ( (*capacity)[e] <= (*flow)[e] ) continue; |
---|
| 667 | Node u=g->tail(e); |
---|
| 668 | if ( level[u] >= n ) { |
---|
| 669 | bfs_queue.push(u); |
---|
| 670 | level.set(u, l); |
---|
| 671 | if ( excess[u] > 0 ) active[l].push(u); |
---|
| 672 | } |
---|
| 673 | } |
---|
| 674 | |
---|
| 675 | OutEdgeIt f; |
---|
| 676 | for(g->first(f,v); g->valid(f); g->next(f)) { |
---|
| 677 | if ( 0 >= (*flow)[f] ) continue; |
---|
| 678 | Node u=g->head(f); |
---|
| 679 | if ( level[u] >= n ) { |
---|
| 680 | bfs_queue.push(u); |
---|
| 681 | level.set(u, l); |
---|
| 682 | if ( excess[u] > 0 ) active[l].push(u); |
---|
| 683 | } |
---|
| 684 | } |
---|
| 685 | } |
---|
| 686 | b=n-2; |
---|
| 687 | |
---|
| 688 | while ( true ) { |
---|
| 689 | |
---|
| 690 | if ( b == 0 ) break; |
---|
| 691 | |
---|
| 692 | if ( active[b].empty() ) --b; |
---|
| 693 | else { |
---|
| 694 | Node w=active[b].top(); |
---|
| 695 | active[b].pop(); |
---|
| 696 | int newlevel=push(w,active); |
---|
| 697 | |
---|
| 698 | //relabel |
---|
| 699 | if ( excess[w] > 0 ) { |
---|
| 700 | level.set(w,++newlevel); |
---|
| 701 | active[newlevel].push(w); |
---|
| 702 | b=newlevel; |
---|
| 703 | } |
---|
| 704 | } // if stack[b] is nonempty |
---|
| 705 | } // while(true) |
---|
| 706 | } |
---|
| 707 | |
---|
| 708 | |
---|
| 709 | |
---|
[472] | 710 | template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
---|
[476] | 711 | bool MaxFlow<Graph, Num, CapMap, FlowMap>::augmentOnShortestPath() |
---|
[472] | 712 | { |
---|
| 713 | ResGW res_graph(*g, *capacity, *flow); |
---|
| 714 | bool _augment=false; |
---|
| 715 | |
---|
| 716 | //ReachedMap level(res_graph); |
---|
| 717 | FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0); |
---|
| 718 | BfsIterator<ResGW, ReachedMap> bfs(res_graph, level); |
---|
| 719 | bfs.pushAndSetReached(s); |
---|
| 720 | |
---|
| 721 | typename ResGW::template NodeMap<ResGWEdge> pred(res_graph); |
---|
| 722 | pred.set(s, INVALID); |
---|
| 723 | |
---|
| 724 | typename ResGW::template NodeMap<Num> free(res_graph); |
---|
| 725 | |
---|
| 726 | //searching for augmenting path |
---|
| 727 | while ( !bfs.finished() ) { |
---|
| 728 | ResGWOutEdgeIt e=bfs; |
---|
| 729 | if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) { |
---|
| 730 | Node v=res_graph.tail(e); |
---|
| 731 | Node w=res_graph.head(e); |
---|
| 732 | pred.set(w, e); |
---|
| 733 | if (res_graph.valid(pred[v])) { |
---|
| 734 | free.set(w, std::min(free[v], res_graph.resCap(e))); |
---|
| 735 | } else { |
---|
| 736 | free.set(w, res_graph.resCap(e)); |
---|
| 737 | } |
---|
| 738 | if (res_graph.head(e)==t) { _augment=true; break; } |
---|
| 739 | } |
---|
| 740 | |
---|
| 741 | ++bfs; |
---|
| 742 | } //end of searching augmenting path |
---|
[471] | 743 | |
---|
[472] | 744 | if (_augment) { |
---|
| 745 | Node n=t; |
---|
| 746 | Num augment_value=free[t]; |
---|
| 747 | while (res_graph.valid(pred[n])) { |
---|
| 748 | ResGWEdge e=pred[n]; |
---|
| 749 | res_graph.augment(e, augment_value); |
---|
| 750 | n=res_graph.tail(e); |
---|
| 751 | } |
---|
| 752 | } |
---|
[471] | 753 | |
---|
[472] | 754 | return _augment; |
---|
| 755 | } |
---|
[471] | 756 | |
---|
| 757 | |
---|
| 758 | |
---|
| 759 | |
---|
| 760 | |
---|
| 761 | |
---|
[109] | 762 | |
---|
[472] | 763 | |
---|
| 764 | |
---|
| 765 | template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
---|
| 766 | template<typename MutableGraph> |
---|
[476] | 767 | bool MaxFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow() |
---|
[472] | 768 | { |
---|
| 769 | typedef MutableGraph MG; |
---|
| 770 | bool _augment=false; |
---|
| 771 | |
---|
| 772 | ResGW res_graph(*g, *capacity, *flow); |
---|
| 773 | |
---|
| 774 | //bfs for distances on the residual graph |
---|
| 775 | //ReachedMap level(res_graph); |
---|
| 776 | FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0); |
---|
| 777 | BfsIterator<ResGW, ReachedMap> bfs(res_graph, level); |
---|
| 778 | bfs.pushAndSetReached(s); |
---|
| 779 | typename ResGW::template NodeMap<int> |
---|
| 780 | dist(res_graph); //filled up with 0's |
---|
| 781 | |
---|
| 782 | //F will contain the physical copy of the residual graph |
---|
| 783 | //with the set of edges which are on shortest paths |
---|
| 784 | MG F; |
---|
| 785 | typename ResGW::template NodeMap<typename MG::Node> |
---|
| 786 | res_graph_to_F(res_graph); |
---|
| 787 | { |
---|
| 788 | typename ResGW::NodeIt n; |
---|
| 789 | for(res_graph.first(n); res_graph.valid(n); res_graph.next(n)) { |
---|
| 790 | res_graph_to_F.set(n, F.addNode()); |
---|
| 791 | } |
---|
| 792 | } |
---|
| 793 | |
---|
| 794 | typename MG::Node sF=res_graph_to_F[s]; |
---|
| 795 | typename MG::Node tF=res_graph_to_F[t]; |
---|
| 796 | typename MG::template EdgeMap<ResGWEdge> original_edge(F); |
---|
| 797 | typename MG::template EdgeMap<Num> residual_capacity(F); |
---|
| 798 | |
---|
| 799 | while ( !bfs.finished() ) { |
---|
| 800 | ResGWOutEdgeIt e=bfs; |
---|
| 801 | if (res_graph.valid(e)) { |
---|
| 802 | if (bfs.isBNodeNewlyReached()) { |
---|
| 803 | dist.set(res_graph.head(e), dist[res_graph.tail(e)]+1); |
---|
| 804 | typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)], res_graph_to_F[res_graph.head(e)]); |
---|
| 805 | original_edge.update(); |
---|
| 806 | original_edge.set(f, e); |
---|
| 807 | residual_capacity.update(); |
---|
| 808 | residual_capacity.set(f, res_graph.resCap(e)); |
---|
| 809 | } else { |
---|
| 810 | if (dist[res_graph.head(e)]==(dist[res_graph.tail(e)]+1)) { |
---|
| 811 | typename MG::Edge f=F.addEdge(res_graph_to_F[res_graph.tail(e)], res_graph_to_F[res_graph.head(e)]); |
---|
| 812 | original_edge.update(); |
---|
| 813 | original_edge.set(f, e); |
---|
| 814 | residual_capacity.update(); |
---|
| 815 | residual_capacity.set(f, res_graph.resCap(e)); |
---|
| 816 | } |
---|
| 817 | } |
---|
| 818 | } |
---|
| 819 | ++bfs; |
---|
| 820 | } //computing distances from s in the residual graph |
---|
| 821 | |
---|
| 822 | bool __augment=true; |
---|
| 823 | |
---|
| 824 | while (__augment) { |
---|
| 825 | __augment=false; |
---|
| 826 | //computing blocking flow with dfs |
---|
| 827 | DfsIterator< MG, typename MG::template NodeMap<bool> > dfs(F); |
---|
| 828 | typename MG::template NodeMap<typename MG::Edge> pred(F); |
---|
| 829 | pred.set(sF, INVALID); |
---|
| 830 | //invalid iterators for sources |
---|
| 831 | |
---|
| 832 | typename MG::template NodeMap<Num> free(F); |
---|
| 833 | |
---|
| 834 | dfs.pushAndSetReached(sF); |
---|
| 835 | while (!dfs.finished()) { |
---|
| 836 | ++dfs; |
---|
| 837 | if (F.valid(/*typename MG::OutEdgeIt*/(dfs))) { |
---|
| 838 | if (dfs.isBNodeNewlyReached()) { |
---|
| 839 | typename MG::Node v=F.aNode(dfs); |
---|
| 840 | typename MG::Node w=F.bNode(dfs); |
---|
| 841 | pred.set(w, dfs); |
---|
| 842 | if (F.valid(pred[v])) { |
---|
| 843 | free.set(w, std::min(free[v], residual_capacity[dfs])); |
---|
| 844 | } else { |
---|
| 845 | free.set(w, residual_capacity[dfs]); |
---|
| 846 | } |
---|
| 847 | if (w==tF) { |
---|
| 848 | __augment=true; |
---|
| 849 | _augment=true; |
---|
| 850 | break; |
---|
| 851 | } |
---|
| 852 | |
---|
| 853 | } else { |
---|
| 854 | F.erase(/*typename MG::OutEdgeIt*/(dfs)); |
---|
| 855 | } |
---|
| 856 | } |
---|
| 857 | } |
---|
| 858 | |
---|
| 859 | if (__augment) { |
---|
| 860 | typename MG::Node n=tF; |
---|
| 861 | Num augment_value=free[tF]; |
---|
| 862 | while (F.valid(pred[n])) { |
---|
| 863 | typename MG::Edge e=pred[n]; |
---|
| 864 | res_graph.augment(original_edge[e], augment_value); |
---|
| 865 | n=F.tail(e); |
---|
| 866 | if (residual_capacity[e]==augment_value) |
---|
| 867 | F.erase(e); |
---|
| 868 | else |
---|
| 869 | residual_capacity.set(e, residual_capacity[e]-augment_value); |
---|
| 870 | } |
---|
| 871 | } |
---|
| 872 | |
---|
| 873 | } |
---|
| 874 | |
---|
| 875 | return _augment; |
---|
| 876 | } |
---|
| 877 | |
---|
| 878 | |
---|
| 879 | |
---|
| 880 | |
---|
| 881 | |
---|
| 882 | |
---|
| 883 | template <typename Graph, typename Num, typename CapMap, typename FlowMap> |
---|
[476] | 884 | bool MaxFlow<Graph, Num, CapMap, FlowMap>::augmentOnBlockingFlow2() |
---|
[472] | 885 | { |
---|
| 886 | bool _augment=false; |
---|
| 887 | |
---|
| 888 | ResGW res_graph(*g, *capacity, *flow); |
---|
| 889 | |
---|
| 890 | //ReachedMap level(res_graph); |
---|
| 891 | FOR_EACH_LOC(typename Graph::NodeIt, e, *g) level.set(e, 0); |
---|
| 892 | BfsIterator<ResGW, ReachedMap> bfs(res_graph, level); |
---|
| 893 | |
---|
| 894 | bfs.pushAndSetReached(s); |
---|
| 895 | DistanceMap<ResGW> dist(res_graph); |
---|
| 896 | while ( !bfs.finished() ) { |
---|
| 897 | ResGWOutEdgeIt e=bfs; |
---|
| 898 | if (res_graph.valid(e) && bfs.isBNodeNewlyReached()) { |
---|
| 899 | dist.set(res_graph.head(e), dist[res_graph.tail(e)]+1); |
---|
| 900 | } |
---|
| 901 | ++bfs; |
---|
| 902 | } //computing distances from s in the residual graph |
---|
| 903 | |
---|
| 904 | //Subgraph containing the edges on some shortest paths |
---|
| 905 | ConstMap<typename ResGW::Node, bool> true_map(true); |
---|
| 906 | typedef SubGraphWrapper<ResGW, ConstMap<typename ResGW::Node, bool>, |
---|
| 907 | DistanceMap<ResGW> > FilterResGW; |
---|
| 908 | FilterResGW filter_res_graph(res_graph, true_map, dist); |
---|
| 909 | |
---|
| 910 | //Subgraph, which is able to delete edges which are already |
---|
| 911 | //met by the dfs |
---|
| 912 | typename FilterResGW::template NodeMap<typename FilterResGW::OutEdgeIt> |
---|
| 913 | first_out_edges(filter_res_graph); |
---|
| 914 | typename FilterResGW::NodeIt v; |
---|
| 915 | for(filter_res_graph.first(v); filter_res_graph.valid(v); |
---|
| 916 | filter_res_graph.next(v)) |
---|
| 917 | { |
---|
| 918 | typename FilterResGW::OutEdgeIt e; |
---|
| 919 | filter_res_graph.first(e, v); |
---|
| 920 | first_out_edges.set(v, e); |
---|
| 921 | } |
---|
| 922 | typedef ErasingFirstGraphWrapper<FilterResGW, typename FilterResGW:: |
---|
| 923 | template NodeMap<typename FilterResGW::OutEdgeIt> > ErasingResGW; |
---|
| 924 | ErasingResGW erasing_res_graph(filter_res_graph, first_out_edges); |
---|
| 925 | |
---|
| 926 | bool __augment=true; |
---|
| 927 | |
---|
| 928 | while (__augment) { |
---|
| 929 | |
---|
| 930 | __augment=false; |
---|
| 931 | //computing blocking flow with dfs |
---|
| 932 | DfsIterator< ErasingResGW, |
---|
| 933 | typename ErasingResGW::template NodeMap<bool> > |
---|
| 934 | dfs(erasing_res_graph); |
---|
| 935 | typename ErasingResGW:: |
---|
| 936 | template NodeMap<typename ErasingResGW::OutEdgeIt> |
---|
| 937 | pred(erasing_res_graph); |
---|
| 938 | pred.set(s, INVALID); |
---|
| 939 | //invalid iterators for sources |
---|
| 940 | |
---|
| 941 | typename ErasingResGW::template NodeMap<Num> |
---|
| 942 | free1(erasing_res_graph); |
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| 943 | |
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| 944 | dfs.pushAndSetReached( |
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| 945 | typename ErasingResGW::Node( |
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| 946 | typename FilterResGW::Node( |
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| 947 | typename ResGW::Node(s) |
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| 948 | ) |
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| 949 | ) |
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| 950 | ); |
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| 951 | while (!dfs.finished()) { |
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| 952 | ++dfs; |
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| 953 | if (erasing_res_graph.valid( |
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| 954 | typename ErasingResGW::OutEdgeIt(dfs))) |
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| 955 | { |
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| 956 | if (dfs.isBNodeNewlyReached()) { |
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| 957 | |
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| 958 | typename ErasingResGW::Node v=erasing_res_graph.aNode(dfs); |
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| 959 | typename ErasingResGW::Node w=erasing_res_graph.bNode(dfs); |
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| 960 | |
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| 961 | pred.set(w, /*typename ErasingResGW::OutEdgeIt*/(dfs)); |
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| 962 | if (erasing_res_graph.valid(pred[v])) { |
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| 963 | free1.set(w, std::min(free1[v], res_graph.resCap( |
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| 964 | typename ErasingResGW::OutEdgeIt(dfs)))); |
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| 965 | } else { |
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| 966 | free1.set(w, res_graph.resCap( |
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| 967 | typename ErasingResGW::OutEdgeIt(dfs))); |
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| 968 | } |
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| 969 | |
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| 970 | if (w==t) { |
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| 971 | __augment=true; |
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| 972 | _augment=true; |
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| 973 | break; |
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| 974 | } |
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| 975 | } else { |
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| 976 | erasing_res_graph.erase(dfs); |
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| 977 | } |
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| 978 | } |
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| 979 | } |
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| 980 | |
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| 981 | if (__augment) { |
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| 982 | typename ErasingResGW::Node n=typename FilterResGW::Node(typename ResGW::Node(t)); |
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| 983 | // typename ResGW::NodeMap<Num> a(res_graph); |
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| 984 | // typename ResGW::Node b; |
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| 985 | // Num j=a[b]; |
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| 986 | // typename FilterResGW::NodeMap<Num> a1(filter_res_graph); |
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| 987 | // typename FilterResGW::Node b1; |
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| 988 | // Num j1=a1[b1]; |
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| 989 | // typename ErasingResGW::NodeMap<Num> a2(erasing_res_graph); |
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| 990 | // typename ErasingResGW::Node b2; |
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| 991 | // Num j2=a2[b2]; |
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| 992 | Num augment_value=free1[n]; |
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| 993 | while (erasing_res_graph.valid(pred[n])) { |
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| 994 | typename ErasingResGW::OutEdgeIt e=pred[n]; |
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| 995 | res_graph.augment(e, augment_value); |
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| 996 | n=erasing_res_graph.tail(e); |
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| 997 | if (res_graph.resCap(e)==0) |
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| 998 | erasing_res_graph.erase(e); |
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| 999 | } |
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| 1000 | } |
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| 1001 | |
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| 1002 | } //while (__augment) |
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| 1003 | |
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| 1004 | return _augment; |
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| 1005 | } |
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| 1006 | |
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| 1007 | |
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| 1008 | |
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| 1009 | |
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[174] | 1010 | } //namespace hugo |
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[109] | 1011 | |
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[451] | 1012 | #endif //HUGO_PREFLOW_H |
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[109] | 1013 | |
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| 1014 | |
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[174] | 1015 | |
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| 1016 | |
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