[389] | 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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| 2 | * |
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| 3 | * This file is a part of LEMON, a generic C++ optimization library. |
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| 4 | * |
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| 5 | * Copyright (C) 2003-2008 |
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| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | #include <fstream> |
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| 20 | #include <string> |
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| 21 | |
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| 22 | #include "test_tools.h" |
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| 23 | #include <lemon/smart_graph.h> |
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| 24 | #include <lemon/preflow.h> |
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| 25 | #include <lemon/concepts/digraph.h> |
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| 26 | #include <lemon/concepts/maps.h> |
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| 27 | #include <lemon/lgf_reader.h> |
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| 28 | |
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| 29 | using namespace lemon; |
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| 30 | |
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| 31 | void checkPreflow() |
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| 32 | { |
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| 33 | typedef int VType; |
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| 34 | typedef concepts::Digraph Digraph; |
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| 35 | |
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| 36 | typedef Digraph::Node Node; |
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| 37 | typedef Digraph::Arc Arc; |
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| 38 | typedef concepts::ReadMap<Arc,VType> CapMap; |
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| 39 | typedef concepts::ReadWriteMap<Arc,VType> FlowMap; |
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| 40 | typedef concepts::WriteMap<Node,bool> CutMap; |
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| 41 | |
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| 42 | Digraph g; |
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| 43 | Node n; |
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| 44 | Arc e; |
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| 45 | CapMap cap; |
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| 46 | FlowMap flow; |
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| 47 | CutMap cut; |
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| 48 | |
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[391] | 49 | Preflow<Digraph, CapMap>::SetFlowMap<FlowMap>::Create preflow_test(g,cap,n,n); |
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[389] | 50 | |
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| 51 | preflow_test.capacityMap(cap); |
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| 52 | flow = preflow_test.flowMap(); |
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| 53 | preflow_test.flowMap(flow); |
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| 54 | preflow_test.source(n); |
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| 55 | preflow_test.target(n); |
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| 56 | |
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| 57 | preflow_test.init(); |
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[392] | 58 | preflow_test.init(cap); |
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[389] | 59 | preflow_test.startFirstPhase(); |
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| 60 | preflow_test.startSecondPhase(); |
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| 61 | preflow_test.run(); |
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| 62 | preflow_test.runMinCut(); |
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| 63 | |
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| 64 | preflow_test.flowValue(); |
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| 65 | preflow_test.minCut(n); |
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| 66 | preflow_test.minCutMap(cut); |
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| 67 | preflow_test.flow(e); |
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| 68 | |
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| 69 | } |
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| 70 | |
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| 71 | int cutValue (const SmartDigraph& g, |
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| 72 | const SmartDigraph::NodeMap<bool>& cut, |
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| 73 | const SmartDigraph::ArcMap<int>& cap) { |
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| 74 | |
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| 75 | int c=0; |
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| 76 | for(SmartDigraph::ArcIt e(g); e!=INVALID; ++e) { |
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| 77 | if (cut[g.source(e)] && !cut[g.target(e)]) c+=cap[e]; |
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| 78 | } |
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| 79 | return c; |
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| 80 | } |
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| 81 | |
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| 82 | bool checkFlow(const SmartDigraph& g, |
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| 83 | const SmartDigraph::ArcMap<int>& flow, |
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| 84 | const SmartDigraph::ArcMap<int>& cap, |
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| 85 | SmartDigraph::Node s, SmartDigraph::Node t) { |
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| 86 | |
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| 87 | for (SmartDigraph::ArcIt e(g); e != INVALID; ++e) { |
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| 88 | if (flow[e] < 0 || flow[e] > cap[e]) return false; |
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| 89 | } |
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| 90 | |
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| 91 | for (SmartDigraph::NodeIt n(g); n != INVALID; ++n) { |
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| 92 | if (n == s || n == t) continue; |
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| 93 | int sum = 0; |
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| 94 | for (SmartDigraph::OutArcIt e(g, n); e != INVALID; ++e) { |
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| 95 | sum += flow[e]; |
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| 96 | } |
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| 97 | for (SmartDigraph::InArcIt e(g, n); e != INVALID; ++e) { |
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| 98 | sum -= flow[e]; |
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| 99 | } |
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| 100 | if (sum != 0) return false; |
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| 101 | } |
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| 102 | return true; |
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| 103 | } |
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| 104 | |
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| 105 | int main() { |
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| 106 | |
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| 107 | typedef SmartDigraph Digraph; |
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| 108 | |
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| 109 | typedef Digraph::Node Node; |
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| 110 | typedef Digraph::NodeIt NodeIt; |
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| 111 | typedef Digraph::ArcIt ArcIt; |
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| 112 | typedef Digraph::ArcMap<int> CapMap; |
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| 113 | typedef Digraph::ArcMap<int> FlowMap; |
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| 114 | typedef Digraph::NodeMap<bool> CutMap; |
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| 115 | |
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| 116 | typedef Preflow<Digraph, CapMap> PType; |
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| 117 | |
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| 118 | std::string f_name; |
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| 119 | if( getenv("srcdir") ) |
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| 120 | f_name = std::string(getenv("srcdir")); |
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| 121 | else f_name = "."; |
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| 122 | f_name += "/test/preflow_graph.lgf"; |
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| 123 | |
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| 124 | std::ifstream file(f_name.c_str()); |
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| 125 | |
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| 126 | check(file, "Input file '" << f_name << "' not found."); |
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| 127 | |
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| 128 | Digraph g; |
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| 129 | Node s, t; |
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| 130 | CapMap cap(g); |
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| 131 | DigraphReader<Digraph>(g,file). |
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| 132 | arcMap("capacity", cap). |
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| 133 | node("source",s). |
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| 134 | node("target",t). |
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| 135 | run(); |
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| 136 | |
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| 137 | PType preflow_test(g, cap, s, t); |
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| 138 | preflow_test.run(); |
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| 139 | |
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| 140 | check(checkFlow(g, preflow_test.flowMap(), cap, s, t), |
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| 141 | "The flow is not feasible."); |
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| 142 | |
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| 143 | CutMap min_cut(g); |
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| 144 | preflow_test.minCutMap(min_cut); |
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| 145 | int min_cut_value=cutValue(g,min_cut,cap); |
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| 146 | |
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| 147 | check(preflow_test.flowValue() == min_cut_value, |
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| 148 | "The max flow value is not equal to the three min cut values."); |
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| 149 | |
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| 150 | FlowMap flow(g); |
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| 151 | for(ArcIt e(g); e!=INVALID; ++e) flow[e] = preflow_test.flowMap()[e]; |
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| 152 | |
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| 153 | int flow_value=preflow_test.flowValue(); |
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| 154 | |
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| 155 | for(ArcIt e(g); e!=INVALID; ++e) cap[e]=2*cap[e]; |
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[392] | 156 | preflow_test.init(flow); |
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[389] | 157 | preflow_test.startFirstPhase(); |
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| 158 | |
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| 159 | CutMap min_cut1(g); |
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| 160 | preflow_test.minCutMap(min_cut1); |
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| 161 | min_cut_value=cutValue(g,min_cut1,cap); |
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| 162 | |
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| 163 | check(preflow_test.flowValue() == min_cut_value && |
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| 164 | min_cut_value == 2*flow_value, |
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| 165 | "The max flow value or the min cut value is wrong."); |
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| 166 | |
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| 167 | preflow_test.startSecondPhase(); |
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| 168 | |
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| 169 | check(checkFlow(g, preflow_test.flowMap(), cap, s, t), |
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| 170 | "The flow is not feasible."); |
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| 171 | |
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| 172 | CutMap min_cut2(g); |
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| 173 | preflow_test.minCutMap(min_cut2); |
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| 174 | min_cut_value=cutValue(g,min_cut2,cap); |
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| 175 | |
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| 176 | check(preflow_test.flowValue() == min_cut_value && |
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| 177 | min_cut_value == 2*flow_value, |
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| 178 | "The max flow value or the three min cut values were not doubled"); |
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| 179 | |
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| 180 | |
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| 181 | preflow_test.flowMap(flow); |
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| 182 | |
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| 183 | NodeIt tmp1(g,s); |
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| 184 | ++tmp1; |
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| 185 | if ( tmp1 != INVALID ) s=tmp1; |
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| 186 | |
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| 187 | NodeIt tmp2(g,t); |
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| 188 | ++tmp2; |
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| 189 | if ( tmp2 != INVALID ) t=tmp2; |
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| 190 | |
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| 191 | preflow_test.source(s); |
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| 192 | preflow_test.target(t); |
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| 193 | |
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| 194 | preflow_test.run(); |
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| 195 | |
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| 196 | CutMap min_cut3(g); |
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| 197 | preflow_test.minCutMap(min_cut3); |
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| 198 | min_cut_value=cutValue(g,min_cut3,cap); |
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| 199 | |
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| 200 | |
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| 201 | check(preflow_test.flowValue() == min_cut_value, |
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| 202 | "The max flow value or the three min cut values are incorrect."); |
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| 203 | |
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| 204 | return 0; |
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| 205 | } |
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