[209] | 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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[100] | 2 | * |
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[209] | 3 | * This file is a part of LEMON, a generic C++ optimization library. |
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[100] | 4 | * |
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[440] | 5 | * Copyright (C) 2003-2009 |
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[100] | 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 | #ifndef LEMON_DFS_H |
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| 20 | #define LEMON_DFS_H |
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| 21 | |
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| 22 | ///\ingroup search |
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| 23 | ///\file |
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[244] | 24 | ///\brief DFS algorithm. |
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[100] | 25 | |
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| 26 | #include <lemon/list_graph.h> |
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| 27 | #include <lemon/bits/path_dump.h> |
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[220] | 28 | #include <lemon/core.h> |
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[100] | 29 | #include <lemon/error.h> |
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| 30 | #include <lemon/maps.h> |
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[278] | 31 | #include <lemon/path.h> |
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[100] | 32 | |
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| 33 | namespace lemon { |
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| 34 | |
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| 35 | ///Default traits class of Dfs class. |
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| 36 | |
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| 37 | ///Default traits class of Dfs class. |
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[157] | 38 | ///\tparam GR Digraph type. |
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[100] | 39 | template<class GR> |
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| 40 | struct DfsDefaultTraits |
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| 41 | { |
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[244] | 42 | ///The type of the digraph the algorithm runs on. |
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[100] | 43 | typedef GR Digraph; |
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[244] | 44 | |
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| 45 | ///\brief The type of the map that stores the predecessor |
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[100] | 46 | ///arcs of the %DFS paths. |
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[209] | 47 | /// |
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[244] | 48 | ///The type of the map that stores the predecessor |
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[100] | 49 | ///arcs of the %DFS paths. |
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| 50 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[244] | 51 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
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[301] | 52 | ///Instantiates a PredMap. |
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[209] | 53 | |
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[301] | 54 | ///This function instantiates a PredMap. |
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[244] | 55 | ///\param g is the digraph, to which we would like to define the |
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[301] | 56 | ///PredMap. |
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[244] | 57 | static PredMap *createPredMap(const Digraph &g) |
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[100] | 58 | { |
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[244] | 59 | return new PredMap(g); |
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[100] | 60 | } |
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| 61 | |
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| 62 | ///The type of the map that indicates which nodes are processed. |
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[209] | 63 | |
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[100] | 64 | ///The type of the map that indicates which nodes are processed. |
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| 65 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 66 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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[301] | 67 | ///Instantiates a ProcessedMap. |
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[209] | 68 | |
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[301] | 69 | ///This function instantiates a ProcessedMap. |
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[100] | 70 | ///\param g is the digraph, to which |
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[301] | 71 | ///we would like to define the ProcessedMap |
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[100] | 72 | #ifdef DOXYGEN |
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[244] | 73 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 74 | #else |
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[244] | 75 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 76 | #endif |
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| 77 | { |
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| 78 | return new ProcessedMap(); |
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| 79 | } |
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[244] | 80 | |
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[100] | 81 | ///The type of the map that indicates which nodes are reached. |
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[209] | 82 | |
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[100] | 83 | ///The type of the map that indicates which nodes are reached. |
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[244] | 84 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 85 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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[301] | 86 | ///Instantiates a ReachedMap. |
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[209] | 87 | |
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[301] | 88 | ///This function instantiates a ReachedMap. |
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[244] | 89 | ///\param g is the digraph, to which |
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[301] | 90 | ///we would like to define the ReachedMap. |
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[244] | 91 | static ReachedMap *createReachedMap(const Digraph &g) |
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[100] | 92 | { |
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[244] | 93 | return new ReachedMap(g); |
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[100] | 94 | } |
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[209] | 95 | |
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[244] | 96 | ///The type of the map that stores the distances of the nodes. |
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| 97 | |
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| 98 | ///The type of the map that stores the distances of the nodes. |
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[100] | 99 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 100 | typedef typename Digraph::template NodeMap<int> DistMap; |
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[301] | 101 | ///Instantiates a DistMap. |
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[209] | 102 | |
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[301] | 103 | ///This function instantiates a DistMap. |
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[244] | 104 | ///\param g is the digraph, to which we would like to define the |
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[301] | 105 | ///DistMap. |
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[244] | 106 | static DistMap *createDistMap(const Digraph &g) |
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[100] | 107 | { |
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[244] | 108 | return new DistMap(g); |
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[100] | 109 | } |
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| 110 | }; |
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[209] | 111 | |
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[100] | 112 | ///%DFS algorithm class. |
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[209] | 113 | |
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[100] | 114 | ///\ingroup search |
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| 115 | ///This class provides an efficient implementation of the %DFS algorithm. |
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| 116 | /// |
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[278] | 117 | ///There is also a \ref dfs() "function-type interface" for the DFS |
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[244] | 118 | ///algorithm, which is convenient in the simplier cases and it can be |
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| 119 | ///used easier. |
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| 120 | /// |
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| 121 | ///\tparam GR The type of the digraph the algorithm runs on. |
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[405] | 122 | ///The default type is \ref ListDigraph. |
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[100] | 123 | #ifdef DOXYGEN |
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| 124 | template <typename GR, |
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[209] | 125 | typename TR> |
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[100] | 126 | #else |
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| 127 | template <typename GR=ListDigraph, |
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[209] | 128 | typename TR=DfsDefaultTraits<GR> > |
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[100] | 129 | #endif |
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| 130 | class Dfs { |
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| 131 | public: |
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| 132 | |
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[244] | 133 | ///The type of the digraph the algorithm runs on. |
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| 134 | typedef typename TR::Digraph Digraph; |
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| 135 | |
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| 136 | ///\brief The type of the map that stores the predecessor arcs of the |
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| 137 | ///DFS paths. |
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| 138 | typedef typename TR::PredMap PredMap; |
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| 139 | ///The type of the map that stores the distances of the nodes. |
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| 140 | typedef typename TR::DistMap DistMap; |
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| 141 | ///The type of the map that indicates which nodes are reached. |
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| 142 | typedef typename TR::ReachedMap ReachedMap; |
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| 143 | ///The type of the map that indicates which nodes are processed. |
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| 144 | typedef typename TR::ProcessedMap ProcessedMap; |
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| 145 | ///The type of the paths. |
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| 146 | typedef PredMapPath<Digraph, PredMap> Path; |
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| 147 | |
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[405] | 148 | ///The \ref DfsDefaultTraits "traits class" of the algorithm. |
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[100] | 149 | typedef TR Traits; |
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[244] | 150 | |
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| 151 | private: |
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| 152 | |
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[100] | 153 | typedef typename Digraph::Node Node; |
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| 154 | typedef typename Digraph::NodeIt NodeIt; |
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| 155 | typedef typename Digraph::Arc Arc; |
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| 156 | typedef typename Digraph::OutArcIt OutArcIt; |
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[209] | 157 | |
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[244] | 158 | //Pointer to the underlying digraph. |
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[100] | 159 | const Digraph *G; |
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[244] | 160 | //Pointer to the map of predecessor arcs. |
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[100] | 161 | PredMap *_pred; |
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[244] | 162 | //Indicates if _pred is locally allocated (true) or not. |
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[100] | 163 | bool local_pred; |
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[244] | 164 | //Pointer to the map of distances. |
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[100] | 165 | DistMap *_dist; |
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[244] | 166 | //Indicates if _dist is locally allocated (true) or not. |
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[100] | 167 | bool local_dist; |
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[244] | 168 | //Pointer to the map of reached status of the nodes. |
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[100] | 169 | ReachedMap *_reached; |
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[244] | 170 | //Indicates if _reached is locally allocated (true) or not. |
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[100] | 171 | bool local_reached; |
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[244] | 172 | //Pointer to the map of processed status of the nodes. |
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[100] | 173 | ProcessedMap *_processed; |
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[244] | 174 | //Indicates if _processed is locally allocated (true) or not. |
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[100] | 175 | bool local_processed; |
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| 176 | |
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| 177 | std::vector<typename Digraph::OutArcIt> _stack; |
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| 178 | int _stack_head; |
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| 179 | |
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[280] | 180 | //Creates the maps if necessary. |
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[209] | 181 | void create_maps() |
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[100] | 182 | { |
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| 183 | if(!_pred) { |
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[209] | 184 | local_pred = true; |
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| 185 | _pred = Traits::createPredMap(*G); |
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[100] | 186 | } |
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| 187 | if(!_dist) { |
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[209] | 188 | local_dist = true; |
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| 189 | _dist = Traits::createDistMap(*G); |
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[100] | 190 | } |
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| 191 | if(!_reached) { |
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[209] | 192 | local_reached = true; |
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| 193 | _reached = Traits::createReachedMap(*G); |
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[100] | 194 | } |
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| 195 | if(!_processed) { |
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[209] | 196 | local_processed = true; |
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| 197 | _processed = Traits::createProcessedMap(*G); |
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[100] | 198 | } |
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| 199 | } |
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| 200 | |
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| 201 | protected: |
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| 202 | |
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| 203 | Dfs() {} |
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[209] | 204 | |
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[100] | 205 | public: |
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| 206 | |
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| 207 | typedef Dfs Create; |
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| 208 | |
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| 209 | ///\name Named template parameters |
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| 210 | |
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| 211 | ///@{ |
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| 212 | |
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| 213 | template <class T> |
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[257] | 214 | struct SetPredMapTraits : public Traits { |
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[100] | 215 | typedef T PredMap; |
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[244] | 216 | static PredMap *createPredMap(const Digraph &) |
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[100] | 217 | { |
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[290] | 218 | LEMON_ASSERT(false, "PredMap is not initialized"); |
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| 219 | return 0; // ignore warnings |
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[100] | 220 | } |
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| 221 | }; |
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| 222 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[301] | 223 | ///PredMap type. |
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[100] | 224 | /// |
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[244] | 225 | ///\ref named-templ-param "Named parameter" for setting |
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[301] | 226 | ///PredMap type. |
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[405] | 227 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 228 | template <class T> |
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[257] | 229 | struct SetPredMap : public Dfs<Digraph, SetPredMapTraits<T> > { |
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| 230 | typedef Dfs<Digraph, SetPredMapTraits<T> > Create; |
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[100] | 231 | }; |
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[209] | 232 | |
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[100] | 233 | template <class T> |
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[257] | 234 | struct SetDistMapTraits : public Traits { |
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[100] | 235 | typedef T DistMap; |
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[209] | 236 | static DistMap *createDistMap(const Digraph &) |
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[100] | 237 | { |
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[290] | 238 | LEMON_ASSERT(false, "DistMap is not initialized"); |
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| 239 | return 0; // ignore warnings |
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[100] | 240 | } |
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| 241 | }; |
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| 242 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[301] | 243 | ///DistMap type. |
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[100] | 244 | /// |
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[244] | 245 | ///\ref named-templ-param "Named parameter" for setting |
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[301] | 246 | ///DistMap type. |
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[405] | 247 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 248 | template <class T> |
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[257] | 249 | struct SetDistMap : public Dfs< Digraph, SetDistMapTraits<T> > { |
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| 250 | typedef Dfs<Digraph, SetDistMapTraits<T> > Create; |
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[100] | 251 | }; |
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[209] | 252 | |
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[100] | 253 | template <class T> |
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[257] | 254 | struct SetReachedMapTraits : public Traits { |
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[100] | 255 | typedef T ReachedMap; |
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[209] | 256 | static ReachedMap *createReachedMap(const Digraph &) |
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[100] | 257 | { |
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[290] | 258 | LEMON_ASSERT(false, "ReachedMap is not initialized"); |
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| 259 | return 0; // ignore warnings |
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[100] | 260 | } |
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| 261 | }; |
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| 262 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[301] | 263 | ///ReachedMap type. |
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[100] | 264 | /// |
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[244] | 265 | ///\ref named-templ-param "Named parameter" for setting |
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[301] | 266 | ///ReachedMap type. |
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[405] | 267 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 268 | template <class T> |
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[257] | 269 | struct SetReachedMap : public Dfs< Digraph, SetReachedMapTraits<T> > { |
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| 270 | typedef Dfs< Digraph, SetReachedMapTraits<T> > Create; |
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[100] | 271 | }; |
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| 272 | |
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| 273 | template <class T> |
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[257] | 274 | struct SetProcessedMapTraits : public Traits { |
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[100] | 275 | typedef T ProcessedMap; |
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[209] | 276 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 277 | { |
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[290] | 278 | LEMON_ASSERT(false, "ProcessedMap is not initialized"); |
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| 279 | return 0; // ignore warnings |
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[100] | 280 | } |
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| 281 | }; |
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| 282 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[301] | 283 | ///ProcessedMap type. |
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[100] | 284 | /// |
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[244] | 285 | ///\ref named-templ-param "Named parameter" for setting |
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[301] | 286 | ///ProcessedMap type. |
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[405] | 287 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 288 | template <class T> |
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[257] | 289 | struct SetProcessedMap : public Dfs< Digraph, SetProcessedMapTraits<T> > { |
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| 290 | typedef Dfs< Digraph, SetProcessedMapTraits<T> > Create; |
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[100] | 291 | }; |
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[209] | 292 | |
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[257] | 293 | struct SetStandardProcessedMapTraits : public Traits { |
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[100] | 294 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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[244] | 295 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 296 | { |
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[244] | 297 | return new ProcessedMap(g); |
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[100] | 298 | } |
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| 299 | }; |
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[244] | 300 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[301] | 301 | ///ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 302 | /// |
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[244] | 303 | ///\ref named-templ-param "Named parameter" for setting |
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[301] | 304 | ///ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[244] | 305 | ///If you don't set it explicitly, it will be automatically allocated. |
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[257] | 306 | struct SetStandardProcessedMap : |
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| 307 | public Dfs< Digraph, SetStandardProcessedMapTraits > { |
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| 308 | typedef Dfs< Digraph, SetStandardProcessedMapTraits > Create; |
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[100] | 309 | }; |
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[209] | 310 | |
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[100] | 311 | ///@} |
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| 312 | |
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[209] | 313 | public: |
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| 314 | |
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[100] | 315 | ///Constructor. |
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[209] | 316 | |
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[244] | 317 | ///Constructor. |
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| 318 | ///\param g The digraph the algorithm runs on. |
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| 319 | Dfs(const Digraph &g) : |
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| 320 | G(&g), |
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[100] | 321 | _pred(NULL), local_pred(false), |
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| 322 | _dist(NULL), local_dist(false), |
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| 323 | _reached(NULL), local_reached(false), |
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| 324 | _processed(NULL), local_processed(false) |
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| 325 | { } |
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[209] | 326 | |
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[100] | 327 | ///Destructor. |
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[209] | 328 | ~Dfs() |
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[100] | 329 | { |
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| 330 | if(local_pred) delete _pred; |
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| 331 | if(local_dist) delete _dist; |
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| 332 | if(local_reached) delete _reached; |
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| 333 | if(local_processed) delete _processed; |
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| 334 | } |
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| 335 | |
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[244] | 336 | ///Sets the map that stores the predecessor arcs. |
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[100] | 337 | |
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[244] | 338 | ///Sets the map that stores the predecessor arcs. |
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[405] | 339 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 340 | ///or \ref init(), an instance will be allocated automatically. |
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| 341 | ///The destructor deallocates this automatically allocated map, |
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| 342 | ///of course. |
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[100] | 343 | ///\return <tt> (*this) </tt> |
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[209] | 344 | Dfs &predMap(PredMap &m) |
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[100] | 345 | { |
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| 346 | if(local_pred) { |
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[209] | 347 | delete _pred; |
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| 348 | local_pred=false; |
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[100] | 349 | } |
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| 350 | _pred = &m; |
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| 351 | return *this; |
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| 352 | } |
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| 353 | |
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[244] | 354 | ///Sets the map that indicates which nodes are reached. |
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[100] | 355 | |
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[244] | 356 | ///Sets the map that indicates which nodes are reached. |
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[405] | 357 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 358 | ///or \ref init(), an instance will be allocated automatically. |
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| 359 | ///The destructor deallocates this automatically allocated map, |
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| 360 | ///of course. |
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[244] | 361 | ///\return <tt> (*this) </tt> |
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| 362 | Dfs &reachedMap(ReachedMap &m) |
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| 363 | { |
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| 364 | if(local_reached) { |
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| 365 | delete _reached; |
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| 366 | local_reached=false; |
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| 367 | } |
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| 368 | _reached = &m; |
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| 369 | return *this; |
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| 370 | } |
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| 371 | |
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| 372 | ///Sets the map that indicates which nodes are processed. |
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| 373 | |
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| 374 | ///Sets the map that indicates which nodes are processed. |
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[405] | 375 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 376 | ///or \ref init(), an instance will be allocated automatically. |
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| 377 | ///The destructor deallocates this automatically allocated map, |
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| 378 | ///of course. |
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[244] | 379 | ///\return <tt> (*this) </tt> |
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| 380 | Dfs &processedMap(ProcessedMap &m) |
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| 381 | { |
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| 382 | if(local_processed) { |
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| 383 | delete _processed; |
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| 384 | local_processed=false; |
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| 385 | } |
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| 386 | _processed = &m; |
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| 387 | return *this; |
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| 388 | } |
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| 389 | |
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| 390 | ///Sets the map that stores the distances of the nodes. |
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| 391 | |
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| 392 | ///Sets the map that stores the distances of the nodes calculated by |
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| 393 | ///the algorithm. |
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[405] | 394 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 395 | ///or \ref init(), an instance will be allocated automatically. |
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| 396 | ///The destructor deallocates this automatically allocated map, |
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| 397 | ///of course. |
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[100] | 398 | ///\return <tt> (*this) </tt> |
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[209] | 399 | Dfs &distMap(DistMap &m) |
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[100] | 400 | { |
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| 401 | if(local_dist) { |
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[209] | 402 | delete _dist; |
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| 403 | local_dist=false; |
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[100] | 404 | } |
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| 405 | _dist = &m; |
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| 406 | return *this; |
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| 407 | } |
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| 408 | |
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[244] | 409 | public: |
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[100] | 410 | |
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[405] | 411 | ///\name Execution Control |
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| 412 | ///The simplest way to execute the DFS algorithm is to use one of the |
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| 413 | ///member functions called \ref run(Node) "run()".\n |
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| 414 | ///If you need more control on the execution, first you have to call |
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| 415 | ///\ref init(), then you can add a source node with \ref addSource() |
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| 416 | ///and perform the actual computation with \ref start(). |
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| 417 | ///This procedure can be repeated if there are nodes that have not |
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| 418 | ///been reached. |
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[100] | 419 | |
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| 420 | ///@{ |
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| 421 | |
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[405] | 422 | ///\brief Initializes the internal data structures. |
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| 423 | /// |
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[100] | 424 | ///Initializes the internal data structures. |
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| 425 | void init() |
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| 426 | { |
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| 427 | create_maps(); |
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| 428 | _stack.resize(countNodes(*G)); |
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| 429 | _stack_head=-1; |
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| 430 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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[209] | 431 | _pred->set(u,INVALID); |
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| 432 | _reached->set(u,false); |
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| 433 | _processed->set(u,false); |
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[100] | 434 | } |
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| 435 | } |
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[209] | 436 | |
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[100] | 437 | ///Adds a new source node. |
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| 438 | |
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| 439 | ///Adds a new source node to the set of nodes to be processed. |
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| 440 | /// |
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[405] | 441 | ///\pre The stack must be empty. Otherwise the algorithm gives |
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| 442 | ///wrong results. (One of the outgoing arcs of all the source nodes |
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| 443 | ///except for the last one will not be visited and distances will |
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| 444 | ///also be wrong.) |
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[100] | 445 | void addSource(Node s) |
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| 446 | { |
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[244] | 447 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
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[100] | 448 | if(!(*_reached)[s]) |
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[209] | 449 | { |
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| 450 | _reached->set(s,true); |
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| 451 | _pred->set(s,INVALID); |
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| 452 | OutArcIt e(*G,s); |
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| 453 | if(e!=INVALID) { |
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| 454 | _stack[++_stack_head]=e; |
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| 455 | _dist->set(s,_stack_head); |
---|
| 456 | } |
---|
| 457 | else { |
---|
| 458 | _processed->set(s,true); |
---|
| 459 | _dist->set(s,0); |
---|
| 460 | } |
---|
| 461 | } |
---|
[100] | 462 | } |
---|
[209] | 463 | |
---|
[100] | 464 | ///Processes the next arc. |
---|
| 465 | |
---|
| 466 | ///Processes the next arc. |
---|
| 467 | /// |
---|
| 468 | ///\return The processed arc. |
---|
| 469 | /// |
---|
[244] | 470 | ///\pre The stack must not be empty. |
---|
[100] | 471 | Arc processNextArc() |
---|
[209] | 472 | { |
---|
[100] | 473 | Node m; |
---|
| 474 | Arc e=_stack[_stack_head]; |
---|
| 475 | if(!(*_reached)[m=G->target(e)]) { |
---|
[209] | 476 | _pred->set(m,e); |
---|
| 477 | _reached->set(m,true); |
---|
| 478 | ++_stack_head; |
---|
| 479 | _stack[_stack_head] = OutArcIt(*G, m); |
---|
| 480 | _dist->set(m,_stack_head); |
---|
[100] | 481 | } |
---|
| 482 | else { |
---|
[209] | 483 | m=G->source(e); |
---|
| 484 | ++_stack[_stack_head]; |
---|
[100] | 485 | } |
---|
| 486 | while(_stack_head>=0 && _stack[_stack_head]==INVALID) { |
---|
[209] | 487 | _processed->set(m,true); |
---|
| 488 | --_stack_head; |
---|
| 489 | if(_stack_head>=0) { |
---|
| 490 | m=G->source(_stack[_stack_head]); |
---|
| 491 | ++_stack[_stack_head]; |
---|
| 492 | } |
---|
[100] | 493 | } |
---|
| 494 | return e; |
---|
| 495 | } |
---|
[244] | 496 | |
---|
[100] | 497 | ///Next arc to be processed. |
---|
| 498 | |
---|
| 499 | ///Next arc to be processed. |
---|
| 500 | /// |
---|
[244] | 501 | ///\return The next arc to be processed or \c INVALID if the stack |
---|
| 502 | ///is empty. |
---|
| 503 | OutArcIt nextArc() const |
---|
[209] | 504 | { |
---|
[100] | 505 | return _stack_head>=0?_stack[_stack_head]:INVALID; |
---|
| 506 | } |
---|
| 507 | |
---|
[405] | 508 | ///Returns \c false if there are nodes to be processed. |
---|
| 509 | |
---|
| 510 | ///Returns \c false if there are nodes to be processed |
---|
| 511 | ///in the queue (stack). |
---|
[244] | 512 | bool emptyQueue() const { return _stack_head<0; } |
---|
| 513 | |
---|
[100] | 514 | ///Returns the number of the nodes to be processed. |
---|
[209] | 515 | |
---|
[405] | 516 | ///Returns the number of the nodes to be processed |
---|
| 517 | ///in the queue (stack). |
---|
[244] | 518 | int queueSize() const { return _stack_head+1; } |
---|
[209] | 519 | |
---|
[100] | 520 | ///Executes the algorithm. |
---|
| 521 | |
---|
| 522 | ///Executes the algorithm. |
---|
| 523 | /// |
---|
[244] | 524 | ///This method runs the %DFS algorithm from the root node |
---|
| 525 | ///in order to compute the DFS path to each node. |
---|
[100] | 526 | /// |
---|
[244] | 527 | /// The algorithm computes |
---|
| 528 | ///- the %DFS tree, |
---|
| 529 | ///- the distance of each node from the root in the %DFS tree. |
---|
[100] | 530 | /// |
---|
[244] | 531 | ///\pre init() must be called and a root node should be |
---|
| 532 | ///added with addSource() before using this function. |
---|
| 533 | /// |
---|
| 534 | ///\note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
| 535 | ///\code |
---|
| 536 | /// while ( !d.emptyQueue() ) { |
---|
| 537 | /// d.processNextArc(); |
---|
| 538 | /// } |
---|
| 539 | ///\endcode |
---|
[100] | 540 | void start() |
---|
| 541 | { |
---|
| 542 | while ( !emptyQueue() ) processNextArc(); |
---|
| 543 | } |
---|
[209] | 544 | |
---|
[244] | 545 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 546 | |
---|
[244] | 547 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 548 | /// |
---|
[244] | 549 | ///This method runs the %DFS algorithm from the root node |
---|
[286] | 550 | ///in order to compute the DFS path to \c t. |
---|
[100] | 551 | /// |
---|
[244] | 552 | ///The algorithm computes |
---|
[286] | 553 | ///- the %DFS path to \c t, |
---|
| 554 | ///- the distance of \c t from the root in the %DFS tree. |
---|
[100] | 555 | /// |
---|
[244] | 556 | ///\pre init() must be called and a root node should be |
---|
| 557 | ///added with addSource() before using this function. |
---|
[286] | 558 | void start(Node t) |
---|
[100] | 559 | { |
---|
[286] | 560 | while ( !emptyQueue() && G->target(_stack[_stack_head])!=t ) |
---|
[209] | 561 | processNextArc(); |
---|
[100] | 562 | } |
---|
[209] | 563 | |
---|
[100] | 564 | ///Executes the algorithm until a condition is met. |
---|
| 565 | |
---|
| 566 | ///Executes the algorithm until a condition is met. |
---|
| 567 | /// |
---|
[244] | 568 | ///This method runs the %DFS algorithm from the root node |
---|
| 569 | ///until an arc \c a with <tt>am[a]</tt> true is found. |
---|
[100] | 570 | /// |
---|
[244] | 571 | ///\param am A \c bool (or convertible) arc map. The algorithm |
---|
| 572 | ///will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
---|
[100] | 573 | /// |
---|
[244] | 574 | ///\return The reached arc \c a with <tt>am[a]</tt> true or |
---|
[100] | 575 | ///\c INVALID if no such arc was found. |
---|
| 576 | /// |
---|
[244] | 577 | ///\pre init() must be called and a root node should be |
---|
| 578 | ///added with addSource() before using this function. |
---|
| 579 | /// |
---|
| 580 | ///\warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
---|
[100] | 581 | ///not a node map. |
---|
[244] | 582 | template<class ArcBoolMap> |
---|
| 583 | Arc start(const ArcBoolMap &am) |
---|
[100] | 584 | { |
---|
[244] | 585 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
---|
[100] | 586 | processNextArc(); |
---|
| 587 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
| 588 | } |
---|
| 589 | |
---|
[286] | 590 | ///Runs the algorithm from the given source node. |
---|
[209] | 591 | |
---|
[244] | 592 | ///This method runs the %DFS algorithm from node \c s |
---|
| 593 | ///in order to compute the DFS path to each node. |
---|
[100] | 594 | /// |
---|
[244] | 595 | ///The algorithm computes |
---|
| 596 | ///- the %DFS tree, |
---|
| 597 | ///- the distance of each node from the root in the %DFS tree. |
---|
| 598 | /// |
---|
| 599 | ///\note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 600 | ///\code |
---|
| 601 | /// d.init(); |
---|
[244] | 602 | /// d.addSource(s); |
---|
| 603 | /// d.start(); |
---|
| 604 | ///\endcode |
---|
| 605 | void run(Node s) { |
---|
| 606 | init(); |
---|
| 607 | addSource(s); |
---|
| 608 | start(); |
---|
| 609 | } |
---|
| 610 | |
---|
| 611 | ///Finds the %DFS path between \c s and \c t. |
---|
| 612 | |
---|
| 613 | ///This method runs the %DFS algorithm from node \c s |
---|
[286] | 614 | ///in order to compute the DFS path to node \c t |
---|
| 615 | ///(it stops searching when \c t is processed) |
---|
[244] | 616 | /// |
---|
[286] | 617 | ///\return \c true if \c t is reachable form \c s. |
---|
[244] | 618 | /// |
---|
| 619 | ///\note Apart from the return value, <tt>d.run(s,t)</tt> is |
---|
| 620 | ///just a shortcut of the following code. |
---|
| 621 | ///\code |
---|
| 622 | /// d.init(); |
---|
| 623 | /// d.addSource(s); |
---|
| 624 | /// d.start(t); |
---|
| 625 | ///\endcode |
---|
[286] | 626 | bool run(Node s,Node t) { |
---|
[244] | 627 | init(); |
---|
| 628 | addSource(s); |
---|
| 629 | start(t); |
---|
[286] | 630 | return reached(t); |
---|
[244] | 631 | } |
---|
| 632 | |
---|
| 633 | ///Runs the algorithm to visit all nodes in the digraph. |
---|
| 634 | |
---|
| 635 | ///This method runs the %DFS algorithm in order to compute the |
---|
| 636 | ///%DFS path to each node. |
---|
| 637 | /// |
---|
| 638 | ///The algorithm computes |
---|
[405] | 639 | ///- the %DFS tree (forest), |
---|
| 640 | ///- the distance of each node from the root(s) in the %DFS tree. |
---|
[244] | 641 | /// |
---|
| 642 | ///\note <tt>d.run()</tt> is just a shortcut of the following code. |
---|
| 643 | ///\code |
---|
| 644 | /// d.init(); |
---|
| 645 | /// for (NodeIt n(digraph); n != INVALID; ++n) { |
---|
| 646 | /// if (!d.reached(n)) { |
---|
| 647 | /// d.addSource(n); |
---|
[100] | 648 | /// d.start(); |
---|
| 649 | /// } |
---|
| 650 | /// } |
---|
| 651 | ///\endcode |
---|
| 652 | void run() { |
---|
| 653 | init(); |
---|
| 654 | for (NodeIt it(*G); it != INVALID; ++it) { |
---|
| 655 | if (!reached(it)) { |
---|
| 656 | addSource(it); |
---|
| 657 | start(); |
---|
| 658 | } |
---|
| 659 | } |
---|
| 660 | } |
---|
| 661 | |
---|
| 662 | ///@} |
---|
| 663 | |
---|
| 664 | ///\name Query Functions |
---|
[405] | 665 | ///The results of the DFS algorithm can be obtained using these |
---|
[100] | 666 | ///functions.\n |
---|
[405] | 667 | ///Either \ref run(Node) "run()" or \ref start() should be called |
---|
| 668 | ///before using them. |
---|
[209] | 669 | |
---|
[100] | 670 | ///@{ |
---|
| 671 | |
---|
[244] | 672 | ///The DFS path to a node. |
---|
[100] | 673 | |
---|
[244] | 674 | ///Returns the DFS path to a node. |
---|
| 675 | /// |
---|
[405] | 676 | ///\warning \c t should be reached from the root(s). |
---|
[244] | 677 | /// |
---|
[405] | 678 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 679 | ///must be called before using this function. |
---|
[244] | 680 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
[209] | 681 | |
---|
[405] | 682 | ///The distance of a node from the root(s). |
---|
[100] | 683 | |
---|
[405] | 684 | ///Returns the distance of a node from the root(s). |
---|
[244] | 685 | /// |
---|
[405] | 686 | ///\warning If node \c v is not reached from the root(s), then |
---|
[244] | 687 | ///the return value of this function is undefined. |
---|
| 688 | /// |
---|
[405] | 689 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 690 | ///must be called before using this function. |
---|
[100] | 691 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 692 | |
---|
[244] | 693 | ///Returns the 'previous arc' of the %DFS tree for a node. |
---|
[100] | 694 | |
---|
[244] | 695 | ///This function returns the 'previous arc' of the %DFS tree for the |
---|
[405] | 696 | ///node \c v, i.e. it returns the last arc of a %DFS path from a |
---|
| 697 | ///root to \c v. It is \c INVALID if \c v is not reached from the |
---|
| 698 | ///root(s) or if \c v is a root. |
---|
[244] | 699 | /// |
---|
| 700 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
[100] | 701 | ///\ref predNode(). |
---|
[244] | 702 | /// |
---|
[405] | 703 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 704 | ///must be called before using this function. |
---|
[100] | 705 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 706 | |
---|
| 707 | ///Returns the 'previous node' of the %DFS tree. |
---|
| 708 | |
---|
[244] | 709 | ///This function returns the 'previous node' of the %DFS |
---|
| 710 | ///tree for the node \c v, i.e. it returns the last but one node |
---|
[405] | 711 | ///from a %DFS path from a root to \c v. It is \c INVALID |
---|
| 712 | ///if \c v is not reached from the root(s) or if \c v is a root. |
---|
[244] | 713 | /// |
---|
| 714 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
| 715 | ///\ref predArc(). |
---|
| 716 | /// |
---|
[405] | 717 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 718 | ///must be called before using this function. |
---|
[100] | 719 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
[209] | 720 | G->source((*_pred)[v]); } |
---|
| 721 | |
---|
[244] | 722 | ///\brief Returns a const reference to the node map that stores the |
---|
| 723 | ///distances of the nodes. |
---|
| 724 | /// |
---|
| 725 | ///Returns a const reference to the node map that stores the |
---|
| 726 | ///distances of the nodes calculated by the algorithm. |
---|
| 727 | /// |
---|
[405] | 728 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
[244] | 729 | ///must be called before using this function. |
---|
[100] | 730 | const DistMap &distMap() const { return *_dist;} |
---|
[209] | 731 | |
---|
[244] | 732 | ///\brief Returns a const reference to the node map that stores the |
---|
| 733 | ///predecessor arcs. |
---|
| 734 | /// |
---|
| 735 | ///Returns a const reference to the node map that stores the predecessor |
---|
| 736 | ///arcs, which form the DFS tree. |
---|
| 737 | /// |
---|
[405] | 738 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
[100] | 739 | ///must be called before using this function. |
---|
| 740 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 741 | |
---|
[405] | 742 | ///Checks if a node is reached from the root(s). |
---|
[100] | 743 | |
---|
[405] | 744 | ///Returns \c true if \c v is reached from the root(s). |
---|
| 745 | /// |
---|
| 746 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
[100] | 747 | ///must be called before using this function. |
---|
[244] | 748 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[209] | 749 | |
---|
[100] | 750 | ///@} |
---|
| 751 | }; |
---|
| 752 | |
---|
[244] | 753 | ///Default traits class of dfs() function. |
---|
[100] | 754 | |
---|
[244] | 755 | ///Default traits class of dfs() function. |
---|
[157] | 756 | ///\tparam GR Digraph type. |
---|
[100] | 757 | template<class GR> |
---|
| 758 | struct DfsWizardDefaultTraits |
---|
| 759 | { |
---|
[244] | 760 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 761 | typedef GR Digraph; |
---|
[244] | 762 | |
---|
| 763 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 764 | ///arcs of the %DFS paths. |
---|
[209] | 765 | /// |
---|
[244] | 766 | ///The type of the map that stores the predecessor |
---|
[100] | 767 | ///arcs of the %DFS paths. |
---|
| 768 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 769 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
---|
[301] | 770 | ///Instantiates a PredMap. |
---|
[209] | 771 | |
---|
[301] | 772 | ///This function instantiates a PredMap. |
---|
[244] | 773 | ///\param g is the digraph, to which we would like to define the |
---|
[301] | 774 | ///PredMap. |
---|
[244] | 775 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 776 | { |
---|
[278] | 777 | return new PredMap(g); |
---|
[100] | 778 | } |
---|
| 779 | |
---|
| 780 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 781 | |
---|
[100] | 782 | ///The type of the map that indicates which nodes are processed. |
---|
| 783 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 784 | ///By default it is a NullMap. |
---|
[100] | 785 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[301] | 786 | ///Instantiates a ProcessedMap. |
---|
[209] | 787 | |
---|
[301] | 788 | ///This function instantiates a ProcessedMap. |
---|
[100] | 789 | ///\param g is the digraph, to which |
---|
[301] | 790 | ///we would like to define the ProcessedMap. |
---|
[100] | 791 | #ifdef DOXYGEN |
---|
[244] | 792 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 793 | #else |
---|
[244] | 794 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 795 | #endif |
---|
| 796 | { |
---|
| 797 | return new ProcessedMap(); |
---|
| 798 | } |
---|
[244] | 799 | |
---|
[100] | 800 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 801 | |
---|
[100] | 802 | ///The type of the map that indicates which nodes are reached. |
---|
[244] | 803 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 804 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[301] | 805 | ///Instantiates a ReachedMap. |
---|
[209] | 806 | |
---|
[301] | 807 | ///This function instantiates a ReachedMap. |
---|
[244] | 808 | ///\param g is the digraph, to which |
---|
[301] | 809 | ///we would like to define the ReachedMap. |
---|
[244] | 810 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 811 | { |
---|
[244] | 812 | return new ReachedMap(g); |
---|
[100] | 813 | } |
---|
[209] | 814 | |
---|
[244] | 815 | ///The type of the map that stores the distances of the nodes. |
---|
| 816 | |
---|
| 817 | ///The type of the map that stores the distances of the nodes. |
---|
[100] | 818 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 819 | typedef typename Digraph::template NodeMap<int> DistMap; |
---|
[301] | 820 | ///Instantiates a DistMap. |
---|
[209] | 821 | |
---|
[301] | 822 | ///This function instantiates a DistMap. |
---|
[210] | 823 | ///\param g is the digraph, to which we would like to define |
---|
[301] | 824 | ///the DistMap |
---|
[244] | 825 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 826 | { |
---|
[278] | 827 | return new DistMap(g); |
---|
[100] | 828 | } |
---|
[278] | 829 | |
---|
| 830 | ///The type of the DFS paths. |
---|
| 831 | |
---|
| 832 | ///The type of the DFS paths. |
---|
| 833 | ///It must meet the \ref concepts::Path "Path" concept. |
---|
| 834 | typedef lemon::Path<Digraph> Path; |
---|
[100] | 835 | }; |
---|
[209] | 836 | |
---|
[313] | 837 | /// Default traits class used by DfsWizard |
---|
[100] | 838 | |
---|
| 839 | /// To make it easier to use Dfs algorithm |
---|
[244] | 840 | /// we have created a wizard class. |
---|
[100] | 841 | /// This \ref DfsWizard class needs default traits, |
---|
[244] | 842 | /// as well as the \ref Dfs class. |
---|
[100] | 843 | /// The \ref DfsWizardBase is a class to be the default traits of the |
---|
| 844 | /// \ref DfsWizard class. |
---|
| 845 | template<class GR> |
---|
| 846 | class DfsWizardBase : public DfsWizardDefaultTraits<GR> |
---|
| 847 | { |
---|
| 848 | |
---|
| 849 | typedef DfsWizardDefaultTraits<GR> Base; |
---|
| 850 | protected: |
---|
[244] | 851 | //The type of the nodes in the digraph. |
---|
[100] | 852 | typedef typename Base::Digraph::Node Node; |
---|
| 853 | |
---|
[244] | 854 | //Pointer to the digraph the algorithm runs on. |
---|
[100] | 855 | void *_g; |
---|
[244] | 856 | //Pointer to the map of reached nodes. |
---|
[100] | 857 | void *_reached; |
---|
[244] | 858 | //Pointer to the map of processed nodes. |
---|
[100] | 859 | void *_processed; |
---|
[244] | 860 | //Pointer to the map of predecessors arcs. |
---|
[100] | 861 | void *_pred; |
---|
[244] | 862 | //Pointer to the map of distances. |
---|
[100] | 863 | void *_dist; |
---|
[278] | 864 | //Pointer to the DFS path to the target node. |
---|
| 865 | void *_path; |
---|
| 866 | //Pointer to the distance of the target node. |
---|
| 867 | int *_di; |
---|
[209] | 868 | |
---|
[100] | 869 | public: |
---|
| 870 | /// Constructor. |
---|
[209] | 871 | |
---|
[100] | 872 | /// This constructor does not require parameters, therefore it initiates |
---|
[278] | 873 | /// all of the attributes to \c 0. |
---|
[100] | 874 | DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[278] | 875 | _dist(0), _path(0), _di(0) {} |
---|
[100] | 876 | |
---|
| 877 | /// Constructor. |
---|
[209] | 878 | |
---|
[278] | 879 | /// This constructor requires one parameter, |
---|
| 880 | /// others are initiated to \c 0. |
---|
[244] | 881 | /// \param g The digraph the algorithm runs on. |
---|
[278] | 882 | DfsWizardBase(const GR &g) : |
---|
[209] | 883 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
---|
[278] | 884 | _reached(0), _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
---|
[100] | 885 | |
---|
| 886 | }; |
---|
[209] | 887 | |
---|
[278] | 888 | /// Auxiliary class for the function-type interface of DFS algorithm. |
---|
[100] | 889 | |
---|
[278] | 890 | /// This auxiliary class is created to implement the |
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| 891 | /// \ref dfs() "function-type interface" of \ref Dfs algorithm. |
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[405] | 892 | /// It does not have own \ref run(Node) "run()" method, it uses the |
---|
| 893 | /// functions and features of the plain \ref Dfs. |
---|
[100] | 894 | /// |
---|
[278] | 895 | /// This class should only be used through the \ref dfs() function, |
---|
| 896 | /// which makes it easier to use the algorithm. |
---|
[100] | 897 | template<class TR> |
---|
| 898 | class DfsWizard : public TR |
---|
| 899 | { |
---|
| 900 | typedef TR Base; |
---|
| 901 | |
---|
[244] | 902 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 903 | typedef typename TR::Digraph Digraph; |
---|
[244] | 904 | |
---|
[100] | 905 | typedef typename Digraph::Node Node; |
---|
| 906 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 907 | typedef typename Digraph::Arc Arc; |
---|
| 908 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
[209] | 909 | |
---|
[244] | 910 | ///\brief The type of the map that stores the predecessor |
---|
[278] | 911 | ///arcs of the DFS paths. |
---|
[244] | 912 | typedef typename TR::PredMap PredMap; |
---|
| 913 | ///\brief The type of the map that stores the distances of the nodes. |
---|
| 914 | typedef typename TR::DistMap DistMap; |
---|
| 915 | ///\brief The type of the map that indicates which nodes are reached. |
---|
[100] | 916 | typedef typename TR::ReachedMap ReachedMap; |
---|
[244] | 917 | ///\brief The type of the map that indicates which nodes are processed. |
---|
[100] | 918 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
[278] | 919 | ///The type of the DFS paths |
---|
| 920 | typedef typename TR::Path Path; |
---|
[100] | 921 | |
---|
| 922 | public: |
---|
[244] | 923 | |
---|
[100] | 924 | /// Constructor. |
---|
| 925 | DfsWizard() : TR() {} |
---|
| 926 | |
---|
| 927 | /// Constructor that requires parameters. |
---|
| 928 | |
---|
| 929 | /// Constructor that requires parameters. |
---|
| 930 | /// These parameters will be the default values for the traits class. |
---|
[278] | 931 | /// \param g The digraph the algorithm runs on. |
---|
| 932 | DfsWizard(const Digraph &g) : |
---|
| 933 | TR(g) {} |
---|
[100] | 934 | |
---|
| 935 | ///Copy constructor |
---|
| 936 | DfsWizard(const TR &b) : TR(b) {} |
---|
| 937 | |
---|
| 938 | ~DfsWizard() {} |
---|
| 939 | |
---|
[278] | 940 | ///Runs DFS algorithm from the given source node. |
---|
[209] | 941 | |
---|
[278] | 942 | ///This method runs DFS algorithm from node \c s |
---|
| 943 | ///in order to compute the DFS path to each node. |
---|
| 944 | void run(Node s) |
---|
| 945 | { |
---|
| 946 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 947 | if (Base::_pred) |
---|
| 948 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 949 | if (Base::_dist) |
---|
| 950 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 951 | if (Base::_reached) |
---|
| 952 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 953 | if (Base::_processed) |
---|
| 954 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 955 | if (s!=INVALID) |
---|
| 956 | alg.run(s); |
---|
| 957 | else |
---|
| 958 | alg.run(); |
---|
| 959 | } |
---|
| 960 | |
---|
| 961 | ///Finds the DFS path between \c s and \c t. |
---|
| 962 | |
---|
| 963 | ///This method runs DFS algorithm from node \c s |
---|
| 964 | ///in order to compute the DFS path to node \c t |
---|
| 965 | ///(it stops searching when \c t is processed). |
---|
| 966 | /// |
---|
| 967 | ///\return \c true if \c t is reachable form \c s. |
---|
| 968 | bool run(Node s, Node t) |
---|
| 969 | { |
---|
| 970 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 971 | if (Base::_pred) |
---|
| 972 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 973 | if (Base::_dist) |
---|
| 974 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 975 | if (Base::_reached) |
---|
| 976 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 977 | if (Base::_processed) |
---|
| 978 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 979 | alg.run(s,t); |
---|
| 980 | if (Base::_path) |
---|
| 981 | *reinterpret_cast<Path*>(Base::_path) = alg.path(t); |
---|
| 982 | if (Base::_di) |
---|
| 983 | *Base::_di = alg.dist(t); |
---|
| 984 | return alg.reached(t); |
---|
| 985 | } |
---|
| 986 | |
---|
| 987 | ///Runs DFS algorithm to visit all nodes in the digraph. |
---|
| 988 | |
---|
| 989 | ///This method runs DFS algorithm in order to compute |
---|
| 990 | ///the DFS path to each node. |
---|
[100] | 991 | void run() |
---|
| 992 | { |
---|
[278] | 993 | run(INVALID); |
---|
[244] | 994 | } |
---|
| 995 | |
---|
[100] | 996 | template<class T> |
---|
[257] | 997 | struct SetPredMapBase : public Base { |
---|
[100] | 998 | typedef T PredMap; |
---|
| 999 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
[257] | 1000 | SetPredMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1001 | }; |
---|
[278] | 1002 | ///\brief \ref named-func-param "Named parameter" |
---|
[301] | 1003 | ///for setting PredMap object. |
---|
[100] | 1004 | /// |
---|
[278] | 1005 | ///\ref named-func-param "Named parameter" |
---|
[301] | 1006 | ///for setting PredMap object. |
---|
[100] | 1007 | template<class T> |
---|
[257] | 1008 | DfsWizard<SetPredMapBase<T> > predMap(const T &t) |
---|
[100] | 1009 | { |
---|
| 1010 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1011 | return DfsWizard<SetPredMapBase<T> >(*this); |
---|
[100] | 1012 | } |
---|
[209] | 1013 | |
---|
[100] | 1014 | template<class T> |
---|
[257] | 1015 | struct SetReachedMapBase : public Base { |
---|
[100] | 1016 | typedef T ReachedMap; |
---|
| 1017 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
[257] | 1018 | SetReachedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1019 | }; |
---|
[278] | 1020 | ///\brief \ref named-func-param "Named parameter" |
---|
[301] | 1021 | ///for setting ReachedMap object. |
---|
[100] | 1022 | /// |
---|
[278] | 1023 | /// \ref named-func-param "Named parameter" |
---|
[301] | 1024 | ///for setting ReachedMap object. |
---|
[100] | 1025 | template<class T> |
---|
[257] | 1026 | DfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
---|
[100] | 1027 | { |
---|
[158] | 1028 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1029 | return DfsWizard<SetReachedMapBase<T> >(*this); |
---|
[100] | 1030 | } |
---|
[209] | 1031 | |
---|
[100] | 1032 | template<class T> |
---|
[278] | 1033 | struct SetDistMapBase : public Base { |
---|
| 1034 | typedef T DistMap; |
---|
| 1035 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
| 1036 | SetDistMapBase(const TR &b) : TR(b) {} |
---|
| 1037 | }; |
---|
| 1038 | ///\brief \ref named-func-param "Named parameter" |
---|
[301] | 1039 | ///for setting DistMap object. |
---|
[278] | 1040 | /// |
---|
| 1041 | /// \ref named-func-param "Named parameter" |
---|
[301] | 1042 | ///for setting DistMap object. |
---|
[278] | 1043 | template<class T> |
---|
| 1044 | DfsWizard<SetDistMapBase<T> > distMap(const T &t) |
---|
| 1045 | { |
---|
| 1046 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1047 | return DfsWizard<SetDistMapBase<T> >(*this); |
---|
| 1048 | } |
---|
| 1049 | |
---|
| 1050 | template<class T> |
---|
[257] | 1051 | struct SetProcessedMapBase : public Base { |
---|
[100] | 1052 | typedef T ProcessedMap; |
---|
| 1053 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
[257] | 1054 | SetProcessedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1055 | }; |
---|
[278] | 1056 | ///\brief \ref named-func-param "Named parameter" |
---|
[301] | 1057 | ///for setting ProcessedMap object. |
---|
[100] | 1058 | /// |
---|
[278] | 1059 | /// \ref named-func-param "Named parameter" |
---|
[301] | 1060 | ///for setting ProcessedMap object. |
---|
[100] | 1061 | template<class T> |
---|
[257] | 1062 | DfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
---|
[100] | 1063 | { |
---|
[158] | 1064 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1065 | return DfsWizard<SetProcessedMapBase<T> >(*this); |
---|
[100] | 1066 | } |
---|
[209] | 1067 | |
---|
[100] | 1068 | template<class T> |
---|
[278] | 1069 | struct SetPathBase : public Base { |
---|
| 1070 | typedef T Path; |
---|
| 1071 | SetPathBase(const TR &b) : TR(b) {} |
---|
[100] | 1072 | }; |
---|
[278] | 1073 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1074 | ///for getting the DFS path to the target node. |
---|
[100] | 1075 | /// |
---|
[278] | 1076 | ///\ref named-func-param "Named parameter" |
---|
| 1077 | ///for getting the DFS path to the target node. |
---|
[100] | 1078 | template<class T> |
---|
[278] | 1079 | DfsWizard<SetPathBase<T> > path(const T &t) |
---|
[100] | 1080 | { |
---|
[278] | 1081 | Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1082 | return DfsWizard<SetPathBase<T> >(*this); |
---|
| 1083 | } |
---|
| 1084 | |
---|
| 1085 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1086 | ///for getting the distance of the target node. |
---|
| 1087 | /// |
---|
| 1088 | ///\ref named-func-param "Named parameter" |
---|
| 1089 | ///for getting the distance of the target node. |
---|
| 1090 | DfsWizard dist(const int &d) |
---|
| 1091 | { |
---|
| 1092 | Base::_di=const_cast<int*>(&d); |
---|
| 1093 | return *this; |
---|
[100] | 1094 | } |
---|
[209] | 1095 | |
---|
[100] | 1096 | }; |
---|
[209] | 1097 | |
---|
[278] | 1098 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1099 | |
---|
| 1100 | ///\ingroup search |
---|
[278] | 1101 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1102 | /// |
---|
[278] | 1103 | ///This function also has several \ref named-func-param "named parameters", |
---|
[100] | 1104 | ///they are declared as the members of class \ref DfsWizard. |
---|
[278] | 1105 | ///The following examples show how to use these parameters. |
---|
[100] | 1106 | ///\code |
---|
[278] | 1107 | /// // Compute the DFS tree |
---|
| 1108 | /// dfs(g).predMap(preds).distMap(dists).run(s); |
---|
| 1109 | /// |
---|
| 1110 | /// // Compute the DFS path from s to t |
---|
| 1111 | /// bool reached = dfs(g).path(p).dist(d).run(s,t); |
---|
[100] | 1112 | ///\endcode |
---|
[405] | 1113 | ///\warning Don't forget to put the \ref DfsWizard::run(Node) "run()" |
---|
[100] | 1114 | ///to the end of the parameter list. |
---|
| 1115 | ///\sa DfsWizard |
---|
| 1116 | ///\sa Dfs |
---|
| 1117 | template<class GR> |
---|
| 1118 | DfsWizard<DfsWizardBase<GR> > |
---|
[278] | 1119 | dfs(const GR &digraph) |
---|
[100] | 1120 | { |
---|
[278] | 1121 | return DfsWizard<DfsWizardBase<GR> >(digraph); |
---|
[100] | 1122 | } |
---|
| 1123 | |
---|
| 1124 | #ifdef DOXYGEN |
---|
[244] | 1125 | /// \brief Visitor class for DFS. |
---|
[209] | 1126 | /// |
---|
[244] | 1127 | /// This class defines the interface of the DfsVisit events, and |
---|
| 1128 | /// it could be the base of a real visitor class. |
---|
[100] | 1129 | template <typename _Digraph> |
---|
| 1130 | struct DfsVisitor { |
---|
| 1131 | typedef _Digraph Digraph; |
---|
| 1132 | typedef typename Digraph::Arc Arc; |
---|
| 1133 | typedef typename Digraph::Node Node; |
---|
[244] | 1134 | /// \brief Called for the source node of the DFS. |
---|
[209] | 1135 | /// |
---|
[244] | 1136 | /// This function is called for the source node of the DFS. |
---|
| 1137 | void start(const Node& node) {} |
---|
| 1138 | /// \brief Called when the source node is leaved. |
---|
| 1139 | /// |
---|
| 1140 | /// This function is called when the source node is leaved. |
---|
| 1141 | void stop(const Node& node) {} |
---|
| 1142 | /// \brief Called when a node is reached first time. |
---|
| 1143 | /// |
---|
| 1144 | /// This function is called when a node is reached first time. |
---|
| 1145 | void reach(const Node& node) {} |
---|
| 1146 | /// \brief Called when an arc reaches a new node. |
---|
| 1147 | /// |
---|
| 1148 | /// This function is called when the DFS finds an arc whose target node |
---|
| 1149 | /// is not reached yet. |
---|
[100] | 1150 | void discover(const Arc& arc) {} |
---|
[244] | 1151 | /// \brief Called when an arc is examined but its target node is |
---|
[100] | 1152 | /// already discovered. |
---|
[209] | 1153 | /// |
---|
[244] | 1154 | /// This function is called when an arc is examined but its target node is |
---|
[100] | 1155 | /// already discovered. |
---|
| 1156 | void examine(const Arc& arc) {} |
---|
[244] | 1157 | /// \brief Called when the DFS steps back from a node. |
---|
[209] | 1158 | /// |
---|
[244] | 1159 | /// This function is called when the DFS steps back from a node. |
---|
| 1160 | void leave(const Node& node) {} |
---|
| 1161 | /// \brief Called when the DFS steps back on an arc. |
---|
[209] | 1162 | /// |
---|
[244] | 1163 | /// This function is called when the DFS steps back on an arc. |
---|
| 1164 | void backtrack(const Arc& arc) {} |
---|
[100] | 1165 | }; |
---|
| 1166 | #else |
---|
| 1167 | template <typename _Digraph> |
---|
| 1168 | struct DfsVisitor { |
---|
| 1169 | typedef _Digraph Digraph; |
---|
| 1170 | typedef typename Digraph::Arc Arc; |
---|
| 1171 | typedef typename Digraph::Node Node; |
---|
| 1172 | void start(const Node&) {} |
---|
| 1173 | void stop(const Node&) {} |
---|
[244] | 1174 | void reach(const Node&) {} |
---|
| 1175 | void discover(const Arc&) {} |
---|
| 1176 | void examine(const Arc&) {} |
---|
| 1177 | void leave(const Node&) {} |
---|
| 1178 | void backtrack(const Arc&) {} |
---|
[100] | 1179 | |
---|
| 1180 | template <typename _Visitor> |
---|
| 1181 | struct Constraints { |
---|
| 1182 | void constraints() { |
---|
[209] | 1183 | Arc arc; |
---|
| 1184 | Node node; |
---|
| 1185 | visitor.start(node); |
---|
| 1186 | visitor.stop(arc); |
---|
[244] | 1187 | visitor.reach(node); |
---|
| 1188 | visitor.discover(arc); |
---|
| 1189 | visitor.examine(arc); |
---|
| 1190 | visitor.leave(node); |
---|
| 1191 | visitor.backtrack(arc); |
---|
[100] | 1192 | } |
---|
| 1193 | _Visitor& visitor; |
---|
| 1194 | }; |
---|
| 1195 | }; |
---|
| 1196 | #endif |
---|
| 1197 | |
---|
| 1198 | /// \brief Default traits class of DfsVisit class. |
---|
| 1199 | /// |
---|
| 1200 | /// Default traits class of DfsVisit class. |
---|
[244] | 1201 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[100] | 1202 | template<class _Digraph> |
---|
| 1203 | struct DfsVisitDefaultTraits { |
---|
| 1204 | |
---|
[244] | 1205 | /// \brief The type of the digraph the algorithm runs on. |
---|
[100] | 1206 | typedef _Digraph Digraph; |
---|
| 1207 | |
---|
| 1208 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1209 | /// |
---|
[100] | 1210 | /// The type of the map that indicates which nodes are reached. |
---|
[244] | 1211 | /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 1212 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1213 | |
---|
[301] | 1214 | /// \brief Instantiates a ReachedMap. |
---|
[100] | 1215 | /// |
---|
[301] | 1216 | /// This function instantiates a ReachedMap. |
---|
[100] | 1217 | /// \param digraph is the digraph, to which |
---|
[301] | 1218 | /// we would like to define the ReachedMap. |
---|
[100] | 1219 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1220 | return new ReachedMap(digraph); |
---|
| 1221 | } |
---|
| 1222 | |
---|
| 1223 | }; |
---|
[209] | 1224 | |
---|
[100] | 1225 | /// \ingroup search |
---|
[244] | 1226 | /// |
---|
| 1227 | /// \brief %DFS algorithm class with visitor interface. |
---|
| 1228 | /// |
---|
[100] | 1229 | /// This class provides an efficient implementation of the %DFS algorithm |
---|
| 1230 | /// with visitor interface. |
---|
| 1231 | /// |
---|
| 1232 | /// The %DfsVisit class provides an alternative interface to the Dfs |
---|
| 1233 | /// class. It works with callback mechanism, the DfsVisit object calls |
---|
[244] | 1234 | /// the member functions of the \c Visitor class on every DFS event. |
---|
[100] | 1235 | /// |
---|
[252] | 1236 | /// This interface of the DFS algorithm should be used in special cases |
---|
| 1237 | /// when extra actions have to be performed in connection with certain |
---|
| 1238 | /// events of the DFS algorithm. Otherwise consider to use Dfs or dfs() |
---|
| 1239 | /// instead. |
---|
| 1240 | /// |
---|
[244] | 1241 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[210] | 1242 | /// The default value is |
---|
[244] | 1243 | /// \ref ListDigraph. The value of _Digraph is not used directly by |
---|
| 1244 | /// \ref DfsVisit, it is only passed to \ref DfsVisitDefaultTraits. |
---|
| 1245 | /// \tparam _Visitor The Visitor type that is used by the algorithm. |
---|
| 1246 | /// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty visitor, which |
---|
| 1247 | /// does not observe the DFS events. If you want to observe the DFS |
---|
| 1248 | /// events, you should implement your own visitor class. |
---|
[209] | 1249 | /// \tparam _Traits Traits class to set various data types used by the |
---|
[100] | 1250 | /// algorithm. The default traits class is |
---|
| 1251 | /// \ref DfsVisitDefaultTraits "DfsVisitDefaultTraits<_Digraph>". |
---|
| 1252 | /// See \ref DfsVisitDefaultTraits for the documentation of |
---|
[244] | 1253 | /// a DFS visit traits class. |
---|
[100] | 1254 | #ifdef DOXYGEN |
---|
| 1255 | template <typename _Digraph, typename _Visitor, typename _Traits> |
---|
| 1256 | #else |
---|
| 1257 | template <typename _Digraph = ListDigraph, |
---|
[209] | 1258 | typename _Visitor = DfsVisitor<_Digraph>, |
---|
[288] | 1259 | typename _Traits = DfsVisitDefaultTraits<_Digraph> > |
---|
[100] | 1260 | #endif |
---|
| 1261 | class DfsVisit { |
---|
| 1262 | public: |
---|
[209] | 1263 | |
---|
[244] | 1264 | ///The traits class. |
---|
[100] | 1265 | typedef _Traits Traits; |
---|
| 1266 | |
---|
[244] | 1267 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 1268 | typedef typename Traits::Digraph Digraph; |
---|
| 1269 | |
---|
[244] | 1270 | ///The visitor type used by the algorithm. |
---|
[100] | 1271 | typedef _Visitor Visitor; |
---|
| 1272 | |
---|
[244] | 1273 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 1274 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1275 | |
---|
| 1276 | private: |
---|
| 1277 | |
---|
| 1278 | typedef typename Digraph::Node Node; |
---|
| 1279 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1280 | typedef typename Digraph::Arc Arc; |
---|
| 1281 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1282 | |
---|
[244] | 1283 | //Pointer to the underlying digraph. |
---|
[100] | 1284 | const Digraph *_digraph; |
---|
[244] | 1285 | //Pointer to the visitor object. |
---|
[100] | 1286 | Visitor *_visitor; |
---|
[244] | 1287 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 1288 | ReachedMap *_reached; |
---|
[244] | 1289 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 1290 | bool local_reached; |
---|
| 1291 | |
---|
| 1292 | std::vector<typename Digraph::Arc> _stack; |
---|
| 1293 | int _stack_head; |
---|
| 1294 | |
---|
[280] | 1295 | //Creates the maps if necessary. |
---|
[100] | 1296 | void create_maps() { |
---|
| 1297 | if(!_reached) { |
---|
[209] | 1298 | local_reached = true; |
---|
| 1299 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1300 | } |
---|
| 1301 | } |
---|
| 1302 | |
---|
| 1303 | protected: |
---|
| 1304 | |
---|
| 1305 | DfsVisit() {} |
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[209] | 1306 | |
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[100] | 1307 | public: |
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| 1308 | |
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| 1309 | typedef DfsVisit Create; |
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| 1310 | |
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[405] | 1311 | /// \name Named Template Parameters |
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[100] | 1312 | |
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| 1313 | ///@{ |
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| 1314 | template <class T> |
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[257] | 1315 | struct SetReachedMapTraits : public Traits { |
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[100] | 1316 | typedef T ReachedMap; |
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| 1317 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
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[290] | 1318 | LEMON_ASSERT(false, "ReachedMap is not initialized"); |
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| 1319 | return 0; // ignore warnings |
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[100] | 1320 | } |
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| 1321 | }; |
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[209] | 1322 | /// \brief \ref named-templ-param "Named parameter" for setting |
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[244] | 1323 | /// ReachedMap type. |
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[100] | 1324 | /// |
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[244] | 1325 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
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[100] | 1326 | template <class T> |
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[257] | 1327 | struct SetReachedMap : public DfsVisit< Digraph, Visitor, |
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| 1328 | SetReachedMapTraits<T> > { |
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| 1329 | typedef DfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
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[100] | 1330 | }; |
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| 1331 | ///@} |
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| 1332 | |
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[209] | 1333 | public: |
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| 1334 | |
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[100] | 1335 | /// \brief Constructor. |
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| 1336 | /// |
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| 1337 | /// Constructor. |
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| 1338 | /// |
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[244] | 1339 | /// \param digraph The digraph the algorithm runs on. |
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| 1340 | /// \param visitor The visitor object of the algorithm. |
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[209] | 1341 | DfsVisit(const Digraph& digraph, Visitor& visitor) |
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[100] | 1342 | : _digraph(&digraph), _visitor(&visitor), |
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[209] | 1343 | _reached(0), local_reached(false) {} |
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| 1344 | |
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[100] | 1345 | /// \brief Destructor. |
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| 1346 | ~DfsVisit() { |
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| 1347 | if(local_reached) delete _reached; |
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| 1348 | } |
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| 1349 | |
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[244] | 1350 | /// \brief Sets the map that indicates which nodes are reached. |
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[100] | 1351 | /// |
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[244] | 1352 | /// Sets the map that indicates which nodes are reached. |
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[405] | 1353 | /// If you don't use this function before calling \ref run(Node) "run()" |
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| 1354 | /// or \ref init(), an instance will be allocated automatically. |
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| 1355 | /// The destructor deallocates this automatically allocated map, |
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| 1356 | /// of course. |
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[100] | 1357 | /// \return <tt> (*this) </tt> |
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| 1358 | DfsVisit &reachedMap(ReachedMap &m) { |
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| 1359 | if(local_reached) { |
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[209] | 1360 | delete _reached; |
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| 1361 | local_reached=false; |
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[100] | 1362 | } |
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| 1363 | _reached = &m; |
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| 1364 | return *this; |
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| 1365 | } |
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| 1366 | |
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| 1367 | public: |
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[244] | 1368 | |
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[405] | 1369 | /// \name Execution Control |
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| 1370 | /// The simplest way to execute the DFS algorithm is to use one of the |
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| 1371 | /// member functions called \ref run(Node) "run()".\n |
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| 1372 | /// If you need more control on the execution, first you have to call |
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| 1373 | /// \ref init(), then you can add a source node with \ref addSource() |
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| 1374 | /// and perform the actual computation with \ref start(). |
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| 1375 | /// This procedure can be repeated if there are nodes that have not |
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| 1376 | /// been reached. |
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[100] | 1377 | |
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| 1378 | /// @{ |
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[244] | 1379 | |
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[100] | 1380 | /// \brief Initializes the internal data structures. |
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| 1381 | /// |
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| 1382 | /// Initializes the internal data structures. |
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| 1383 | void init() { |
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| 1384 | create_maps(); |
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| 1385 | _stack.resize(countNodes(*_digraph)); |
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| 1386 | _stack_head = -1; |
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| 1387 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
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[209] | 1388 | _reached->set(u, false); |
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[100] | 1389 | } |
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| 1390 | } |
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[209] | 1391 | |
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[405] | 1392 | /// \brief Adds a new source node. |
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[100] | 1393 | /// |
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[405] | 1394 | /// Adds a new source node to the set of nodes to be processed. |
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[244] | 1395 | /// |
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[405] | 1396 | /// \pre The stack must be empty. Otherwise the algorithm gives |
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| 1397 | /// wrong results. (One of the outgoing arcs of all the source nodes |
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| 1398 | /// except for the last one will not be visited and distances will |
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| 1399 | /// also be wrong.) |
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[244] | 1400 | void addSource(Node s) |
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| 1401 | { |
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| 1402 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
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[100] | 1403 | if(!(*_reached)[s]) { |
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[209] | 1404 | _reached->set(s,true); |
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| 1405 | _visitor->start(s); |
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| 1406 | _visitor->reach(s); |
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| 1407 | Arc e; |
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| 1408 | _digraph->firstOut(e, s); |
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| 1409 | if (e != INVALID) { |
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| 1410 | _stack[++_stack_head] = e; |
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| 1411 | } else { |
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| 1412 | _visitor->leave(s); |
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[419] | 1413 | _visitor->stop(s); |
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[209] | 1414 | } |
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| 1415 | } |
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[100] | 1416 | } |
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[209] | 1417 | |
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[100] | 1418 | /// \brief Processes the next arc. |
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| 1419 | /// |
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| 1420 | /// Processes the next arc. |
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| 1421 | /// |
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| 1422 | /// \return The processed arc. |
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| 1423 | /// |
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[244] | 1424 | /// \pre The stack must not be empty. |
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[209] | 1425 | Arc processNextArc() { |
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[100] | 1426 | Arc e = _stack[_stack_head]; |
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| 1427 | Node m = _digraph->target(e); |
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| 1428 | if(!(*_reached)[m]) { |
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[209] | 1429 | _visitor->discover(e); |
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| 1430 | _visitor->reach(m); |
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| 1431 | _reached->set(m, true); |
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| 1432 | _digraph->firstOut(_stack[++_stack_head], m); |
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[100] | 1433 | } else { |
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[209] | 1434 | _visitor->examine(e); |
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| 1435 | m = _digraph->source(e); |
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| 1436 | _digraph->nextOut(_stack[_stack_head]); |
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[100] | 1437 | } |
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| 1438 | while (_stack_head>=0 && _stack[_stack_head] == INVALID) { |
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[209] | 1439 | _visitor->leave(m); |
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| 1440 | --_stack_head; |
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| 1441 | if (_stack_head >= 0) { |
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| 1442 | _visitor->backtrack(_stack[_stack_head]); |
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| 1443 | m = _digraph->source(_stack[_stack_head]); |
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| 1444 | _digraph->nextOut(_stack[_stack_head]); |
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| 1445 | } else { |
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| 1446 | _visitor->stop(m); |
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| 1447 | } |
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[100] | 1448 | } |
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| 1449 | return e; |
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| 1450 | } |
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| 1451 | |
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| 1452 | /// \brief Next arc to be processed. |
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| 1453 | /// |
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| 1454 | /// Next arc to be processed. |
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| 1455 | /// |
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| 1456 | /// \return The next arc to be processed or INVALID if the stack is |
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| 1457 | /// empty. |
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[244] | 1458 | Arc nextArc() const { |
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[100] | 1459 | return _stack_head >= 0 ? _stack[_stack_head] : INVALID; |
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| 1460 | } |
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| 1461 | |
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| 1462 | /// \brief Returns \c false if there are nodes |
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[244] | 1463 | /// to be processed. |
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[100] | 1464 | /// |
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| 1465 | /// Returns \c false if there are nodes |
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[244] | 1466 | /// to be processed in the queue (stack). |
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| 1467 | bool emptyQueue() const { return _stack_head < 0; } |
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[100] | 1468 | |
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| 1469 | /// \brief Returns the number of the nodes to be processed. |
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| 1470 | /// |
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[244] | 1471 | /// Returns the number of the nodes to be processed in the queue (stack). |
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| 1472 | int queueSize() const { return _stack_head + 1; } |
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[209] | 1473 | |
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[100] | 1474 | /// \brief Executes the algorithm. |
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| 1475 | /// |
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| 1476 | /// Executes the algorithm. |
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| 1477 | /// |
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[244] | 1478 | /// This method runs the %DFS algorithm from the root node |
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| 1479 | /// in order to compute the %DFS path to each node. |
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| 1480 | /// |
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| 1481 | /// The algorithm computes |
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| 1482 | /// - the %DFS tree, |
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| 1483 | /// - the distance of each node from the root in the %DFS tree. |
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| 1484 | /// |
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| 1485 | /// \pre init() must be called and a root node should be |
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| 1486 | /// added with addSource() before using this function. |
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| 1487 | /// |
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| 1488 | /// \note <tt>d.start()</tt> is just a shortcut of the following code. |
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| 1489 | /// \code |
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| 1490 | /// while ( !d.emptyQueue() ) { |
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| 1491 | /// d.processNextArc(); |
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| 1492 | /// } |
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| 1493 | /// \endcode |
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[100] | 1494 | void start() { |
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| 1495 | while ( !emptyQueue() ) processNextArc(); |
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| 1496 | } |
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[209] | 1497 | |
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[244] | 1498 | /// \brief Executes the algorithm until the given target node is reached. |
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[100] | 1499 | /// |
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[244] | 1500 | /// Executes the algorithm until the given target node is reached. |
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[100] | 1501 | /// |
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[244] | 1502 | /// This method runs the %DFS algorithm from the root node |
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[286] | 1503 | /// in order to compute the DFS path to \c t. |
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[244] | 1504 | /// |
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| 1505 | /// The algorithm computes |
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[286] | 1506 | /// - the %DFS path to \c t, |
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| 1507 | /// - the distance of \c t from the root in the %DFS tree. |
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[244] | 1508 | /// |
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| 1509 | /// \pre init() must be called and a root node should be added |
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[100] | 1510 | /// with addSource() before using this function. |
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[286] | 1511 | void start(Node t) { |
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| 1512 | while ( !emptyQueue() && _digraph->target(_stack[_stack_head]) != t ) |
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[209] | 1513 | processNextArc(); |
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[100] | 1514 | } |
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[209] | 1515 | |
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[100] | 1516 | /// \brief Executes the algorithm until a condition is met. |
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| 1517 | /// |
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| 1518 | /// Executes the algorithm until a condition is met. |
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| 1519 | /// |
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[244] | 1520 | /// This method runs the %DFS algorithm from the root node |
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| 1521 | /// until an arc \c a with <tt>am[a]</tt> true is found. |
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| 1522 | /// |
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| 1523 | /// \param am A \c bool (or convertible) arc map. The algorithm |
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| 1524 | /// will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
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| 1525 | /// |
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| 1526 | /// \return The reached arc \c a with <tt>am[a]</tt> true or |
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| 1527 | /// \c INVALID if no such arc was found. |
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| 1528 | /// |
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| 1529 | /// \pre init() must be called and a root node should be added |
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[100] | 1530 | /// with addSource() before using this function. |
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| 1531 | /// |
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[244] | 1532 | /// \warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
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[100] | 1533 | /// not a node map. |
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[244] | 1534 | template <typename AM> |
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| 1535 | Arc start(const AM &am) { |
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| 1536 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
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[100] | 1537 | processNextArc(); |
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| 1538 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
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| 1539 | } |
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| 1540 | |
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[286] | 1541 | /// \brief Runs the algorithm from the given source node. |
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[100] | 1542 | /// |
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[244] | 1543 | /// This method runs the %DFS algorithm from node \c s. |
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| 1544 | /// in order to compute the DFS path to each node. |
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| 1545 | /// |
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| 1546 | /// The algorithm computes |
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| 1547 | /// - the %DFS tree, |
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| 1548 | /// - the distance of each node from the root in the %DFS tree. |
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| 1549 | /// |
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| 1550 | /// \note <tt>d.run(s)</tt> is just a shortcut of the following code. |
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[100] | 1551 | ///\code |
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| 1552 | /// d.init(); |
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| 1553 | /// d.addSource(s); |
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| 1554 | /// d.start(); |
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| 1555 | ///\endcode |
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| 1556 | void run(Node s) { |
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| 1557 | init(); |
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| 1558 | addSource(s); |
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| 1559 | start(); |
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| 1560 | } |
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| 1561 | |
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[244] | 1562 | /// \brief Finds the %DFS path between \c s and \c t. |
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| 1563 | |
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| 1564 | /// This method runs the %DFS algorithm from node \c s |
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[286] | 1565 | /// in order to compute the DFS path to node \c t |
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| 1566 | /// (it stops searching when \c t is processed). |
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[244] | 1567 | /// |
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[286] | 1568 | /// \return \c true if \c t is reachable form \c s. |
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[244] | 1569 | /// |
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| 1570 | /// \note Apart from the return value, <tt>d.run(s,t)</tt> is |
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| 1571 | /// just a shortcut of the following code. |
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| 1572 | ///\code |
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| 1573 | /// d.init(); |
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| 1574 | /// d.addSource(s); |
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| 1575 | /// d.start(t); |
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| 1576 | ///\endcode |
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[286] | 1577 | bool run(Node s,Node t) { |
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[244] | 1578 | init(); |
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| 1579 | addSource(s); |
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| 1580 | start(t); |
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[286] | 1581 | return reached(t); |
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[244] | 1582 | } |
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| 1583 | |
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| 1584 | /// \brief Runs the algorithm to visit all nodes in the digraph. |
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[209] | 1585 | |
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[100] | 1586 | /// This method runs the %DFS algorithm in order to |
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[244] | 1587 | /// compute the %DFS path to each node. |
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[100] | 1588 | /// |
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[244] | 1589 | /// The algorithm computes |
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[405] | 1590 | /// - the %DFS tree (forest), |
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| 1591 | /// - the distance of each node from the root(s) in the %DFS tree. |
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[244] | 1592 | /// |
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| 1593 | /// \note <tt>d.run()</tt> is just a shortcut of the following code. |
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[100] | 1594 | ///\code |
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[244] | 1595 | /// d.init(); |
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| 1596 | /// for (NodeIt n(digraph); n != INVALID; ++n) { |
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| 1597 | /// if (!d.reached(n)) { |
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| 1598 | /// d.addSource(n); |
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| 1599 | /// d.start(); |
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| 1600 | /// } |
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| 1601 | /// } |
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[100] | 1602 | ///\endcode |
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| 1603 | void run() { |
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| 1604 | init(); |
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| 1605 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
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| 1606 | if (!reached(it)) { |
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| 1607 | addSource(it); |
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| 1608 | start(); |
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| 1609 | } |
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| 1610 | } |
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| 1611 | } |
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[244] | 1612 | |
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[100] | 1613 | ///@} |
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| 1614 | |
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| 1615 | /// \name Query Functions |
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[405] | 1616 | /// The results of the DFS algorithm can be obtained using these |
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[100] | 1617 | /// functions.\n |
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[405] | 1618 | /// Either \ref run(Node) "run()" or \ref start() should be called |
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| 1619 | /// before using them. |
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| 1620 | |
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[100] | 1621 | ///@{ |
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[244] | 1622 | |
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[405] | 1623 | /// \brief Checks if a node is reached from the root(s). |
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[100] | 1624 | /// |
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[405] | 1625 | /// Returns \c true if \c v is reached from the root(s). |
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| 1626 | /// |
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| 1627 | /// \pre Either \ref run(Node) "run()" or \ref init() |
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[100] | 1628 | /// must be called before using this function. |
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[420] | 1629 | bool reached(Node v) const { return (*_reached)[v]; } |
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[244] | 1630 | |
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[100] | 1631 | ///@} |
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[244] | 1632 | |
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[100] | 1633 | }; |
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| 1634 | |
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| 1635 | } //END OF NAMESPACE LEMON |
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| 1636 | |
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| 1637 | #endif |
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