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