[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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| 5 | * Copyright (C) 2003-2008 |
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| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | #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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[244] | 30 | #include <lemon/assert.h> |
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[100] | 31 | #include <lemon/maps.h> |
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[278] | 32 | #include <lemon/path.h> |
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[100] | 33 | |
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| 34 | namespace lemon { |
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| 35 | |
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| 36 | ///Default traits class of Dfs class. |
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| 37 | |
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| 38 | ///Default traits class of Dfs class. |
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[157] | 39 | ///\tparam GR Digraph type. |
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[100] | 40 | template<class GR> |
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| 41 | struct DfsDefaultTraits |
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| 42 | { |
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[244] | 43 | ///The type of the digraph the algorithm runs on. |
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[100] | 44 | typedef GR Digraph; |
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[244] | 45 | |
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| 46 | ///\brief The type of the map that stores the predecessor |
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[100] | 47 | ///arcs of the %DFS paths. |
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[209] | 48 | /// |
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[244] | 49 | ///The type of the map that stores the predecessor |
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[100] | 50 | ///arcs of the %DFS paths. |
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| 51 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[244] | 52 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
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| 53 | ///Instantiates a \ref PredMap. |
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[209] | 54 | |
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| 55 | ///This function instantiates a \ref PredMap. |
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[244] | 56 | ///\param g is the digraph, to which we would like to define the |
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| 57 | ///\ref PredMap. |
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| 58 | static PredMap *createPredMap(const Digraph &g) |
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[100] | 59 | { |
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[244] | 60 | return new PredMap(g); |
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[100] | 61 | } |
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| 62 | |
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| 63 | ///The type of the map that indicates which nodes are processed. |
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[209] | 64 | |
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[100] | 65 | ///The type of the map that indicates which nodes are processed. |
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| 66 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 67 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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[244] | 68 | ///Instantiates a \ref ProcessedMap. |
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[209] | 69 | |
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| 70 | ///This function instantiates a \ref ProcessedMap. |
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[100] | 71 | ///\param g is the digraph, to which |
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| 72 | ///we would like to define the \ref ProcessedMap |
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| 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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[244] | 85 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 86 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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[244] | 87 | ///Instantiates a \ref ReachedMap. |
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[209] | 88 | |
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| 89 | ///This function instantiates a \ref ReachedMap. |
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[244] | 90 | ///\param g is the digraph, to which |
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[100] | 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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[100] | 100 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 101 | typedef typename Digraph::template NodeMap<int> DistMap; |
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[244] | 102 | ///Instantiates a \ref DistMap. |
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[209] | 103 | |
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| 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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| 106 | ///\ref DistMap. |
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| 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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| 123 | ///The default value is \ref ListDigraph. The value of GR is not used |
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| 124 | ///directly by \ref Dfs, it is only passed to \ref DfsDefaultTraits. |
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[157] | 125 | ///\tparam TR Traits class to set various data types used by the algorithm. |
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[100] | 126 | ///The default traits class is |
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| 127 | ///\ref DfsDefaultTraits "DfsDefaultTraits<GR>". |
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| 128 | ///See \ref DfsDefaultTraits for the documentation of |
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| 129 | ///a Dfs traits class. |
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| 130 | #ifdef DOXYGEN |
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| 131 | template <typename GR, |
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[209] | 132 | typename TR> |
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[100] | 133 | #else |
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| 134 | template <typename GR=ListDigraph, |
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[209] | 135 | typename TR=DfsDefaultTraits<GR> > |
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[100] | 136 | #endif |
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| 137 | class Dfs { |
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| 138 | public: |
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| 139 | |
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[244] | 140 | ///The type of the digraph the algorithm runs on. |
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| 141 | typedef typename TR::Digraph Digraph; |
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| 142 | |
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| 143 | ///\brief The type of the map that stores the predecessor arcs of the |
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| 144 | ///DFS paths. |
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| 145 | typedef typename TR::PredMap PredMap; |
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| 146 | ///The type of the map that stores the distances of the nodes. |
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| 147 | typedef typename TR::DistMap DistMap; |
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| 148 | ///The type of the map that indicates which nodes are reached. |
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| 149 | typedef typename TR::ReachedMap ReachedMap; |
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| 150 | ///The type of the map that indicates which nodes are processed. |
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| 151 | typedef typename TR::ProcessedMap ProcessedMap; |
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| 152 | ///The type of the paths. |
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| 153 | typedef PredMapPath<Digraph, PredMap> Path; |
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| 154 | |
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| 155 | ///The traits class. |
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[100] | 156 | typedef TR Traits; |
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[244] | 157 | |
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| 158 | private: |
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| 159 | |
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[100] | 160 | typedef typename Digraph::Node Node; |
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| 161 | typedef typename Digraph::NodeIt NodeIt; |
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| 162 | typedef typename Digraph::Arc Arc; |
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| 163 | typedef typename Digraph::OutArcIt OutArcIt; |
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[209] | 164 | |
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[244] | 165 | //Pointer to the underlying digraph. |
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[100] | 166 | const Digraph *G; |
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[244] | 167 | //Pointer to the map of predecessor arcs. |
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[100] | 168 | PredMap *_pred; |
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[244] | 169 | //Indicates if _pred is locally allocated (true) or not. |
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[100] | 170 | bool local_pred; |
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[244] | 171 | //Pointer to the map of distances. |
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[100] | 172 | DistMap *_dist; |
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[244] | 173 | //Indicates if _dist is locally allocated (true) or not. |
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[100] | 174 | bool local_dist; |
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[244] | 175 | //Pointer to the map of reached status of the nodes. |
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[100] | 176 | ReachedMap *_reached; |
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[244] | 177 | //Indicates if _reached is locally allocated (true) or not. |
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[100] | 178 | bool local_reached; |
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[244] | 179 | //Pointer to the map of processed status of the nodes. |
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[100] | 180 | ProcessedMap *_processed; |
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[244] | 181 | //Indicates if _processed is locally allocated (true) or not. |
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[100] | 182 | bool local_processed; |
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| 183 | |
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| 184 | std::vector<typename Digraph::OutArcIt> _stack; |
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| 185 | int _stack_head; |
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| 186 | |
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[280] | 187 | //Creates the maps if necessary. |
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[209] | 188 | void create_maps() |
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[100] | 189 | { |
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| 190 | if(!_pred) { |
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[209] | 191 | local_pred = true; |
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| 192 | _pred = Traits::createPredMap(*G); |
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[100] | 193 | } |
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| 194 | if(!_dist) { |
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[209] | 195 | local_dist = true; |
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| 196 | _dist = Traits::createDistMap(*G); |
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[100] | 197 | } |
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| 198 | if(!_reached) { |
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[209] | 199 | local_reached = true; |
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| 200 | _reached = Traits::createReachedMap(*G); |
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[100] | 201 | } |
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| 202 | if(!_processed) { |
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[209] | 203 | local_processed = true; |
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| 204 | _processed = Traits::createProcessedMap(*G); |
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[100] | 205 | } |
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| 206 | } |
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| 207 | |
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| 208 | protected: |
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| 209 | |
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| 210 | Dfs() {} |
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[209] | 211 | |
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[100] | 212 | public: |
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| 213 | |
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| 214 | typedef Dfs Create; |
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| 215 | |
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| 216 | ///\name Named template parameters |
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| 217 | |
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| 218 | ///@{ |
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| 219 | |
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| 220 | template <class T> |
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[257] | 221 | struct SetPredMapTraits : public Traits { |
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[100] | 222 | typedef T PredMap; |
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[244] | 223 | static PredMap *createPredMap(const Digraph &) |
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[100] | 224 | { |
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[290] | 225 | LEMON_ASSERT(false, "PredMap is not initialized"); |
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| 226 | return 0; // ignore warnings |
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[100] | 227 | } |
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| 228 | }; |
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| 229 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 230 | ///\ref PredMap type. |
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[100] | 231 | /// |
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[244] | 232 | ///\ref named-templ-param "Named parameter" for setting |
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| 233 | ///\ref PredMap type. |
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[100] | 234 | template <class T> |
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[257] | 235 | struct SetPredMap : public Dfs<Digraph, SetPredMapTraits<T> > { |
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| 236 | typedef Dfs<Digraph, SetPredMapTraits<T> > Create; |
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[100] | 237 | }; |
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[209] | 238 | |
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[100] | 239 | template <class T> |
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[257] | 240 | struct SetDistMapTraits : public Traits { |
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[100] | 241 | typedef T DistMap; |
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[209] | 242 | static DistMap *createDistMap(const Digraph &) |
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[100] | 243 | { |
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[290] | 244 | LEMON_ASSERT(false, "DistMap is not initialized"); |
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| 245 | return 0; // ignore warnings |
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[100] | 246 | } |
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| 247 | }; |
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| 248 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 249 | ///\ref DistMap type. |
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[100] | 250 | /// |
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[244] | 251 | ///\ref named-templ-param "Named parameter" for setting |
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| 252 | ///\ref DistMap type. |
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[100] | 253 | template <class T> |
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[257] | 254 | struct SetDistMap : public Dfs< Digraph, SetDistMapTraits<T> > { |
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| 255 | typedef Dfs<Digraph, SetDistMapTraits<T> > Create; |
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[100] | 256 | }; |
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[209] | 257 | |
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[100] | 258 | template <class T> |
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[257] | 259 | struct SetReachedMapTraits : public Traits { |
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[100] | 260 | typedef T ReachedMap; |
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[209] | 261 | static ReachedMap *createReachedMap(const Digraph &) |
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[100] | 262 | { |
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[290] | 263 | LEMON_ASSERT(false, "ReachedMap is not initialized"); |
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| 264 | return 0; // ignore warnings |
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[100] | 265 | } |
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| 266 | }; |
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| 267 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 268 | ///\ref ReachedMap type. |
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[100] | 269 | /// |
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[244] | 270 | ///\ref named-templ-param "Named parameter" for setting |
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| 271 | ///\ref ReachedMap type. |
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[100] | 272 | template <class T> |
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[257] | 273 | struct SetReachedMap : public Dfs< Digraph, SetReachedMapTraits<T> > { |
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| 274 | typedef Dfs< Digraph, SetReachedMapTraits<T> > Create; |
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[100] | 275 | }; |
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| 276 | |
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| 277 | template <class T> |
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[257] | 278 | struct SetProcessedMapTraits : public Traits { |
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[100] | 279 | typedef T ProcessedMap; |
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[209] | 280 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 281 | { |
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[290] | 282 | LEMON_ASSERT(false, "ProcessedMap is not initialized"); |
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| 283 | return 0; // ignore warnings |
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[100] | 284 | } |
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| 285 | }; |
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| 286 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 287 | ///\ref ProcessedMap type. |
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[100] | 288 | /// |
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[244] | 289 | ///\ref named-templ-param "Named parameter" for setting |
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| 290 | ///\ref ProcessedMap type. |
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[100] | 291 | template <class T> |
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[257] | 292 | struct SetProcessedMap : public Dfs< Digraph, SetProcessedMapTraits<T> > { |
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| 293 | typedef Dfs< Digraph, SetProcessedMapTraits<T> > Create; |
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[100] | 294 | }; |
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[209] | 295 | |
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[257] | 296 | struct SetStandardProcessedMapTraits : public Traits { |
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[100] | 297 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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[244] | 298 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 299 | { |
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[244] | 300 | return new ProcessedMap(g); |
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[100] | 301 | } |
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| 302 | }; |
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[244] | 303 | ///\brief \ref named-templ-param "Named parameter" for setting |
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| 304 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 305 | /// |
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[244] | 306 | ///\ref named-templ-param "Named parameter" for setting |
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| 307 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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| 308 | ///If you don't set it explicitly, it will be automatically allocated. |
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[257] | 309 | struct SetStandardProcessedMap : |
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| 310 | public Dfs< Digraph, SetStandardProcessedMapTraits > { |
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| 311 | typedef Dfs< Digraph, SetStandardProcessedMapTraits > Create; |
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[100] | 312 | }; |
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[209] | 313 | |
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[100] | 314 | ///@} |
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| 315 | |
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[209] | 316 | public: |
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| 317 | |
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[100] | 318 | ///Constructor. |
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[209] | 319 | |
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[244] | 320 | ///Constructor. |
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| 321 | ///\param g The digraph the algorithm runs on. |
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| 322 | Dfs(const Digraph &g) : |
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| 323 | G(&g), |
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[100] | 324 | _pred(NULL), local_pred(false), |
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| 325 | _dist(NULL), local_dist(false), |
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| 326 | _reached(NULL), local_reached(false), |
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| 327 | _processed(NULL), local_processed(false) |
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| 328 | { } |
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[209] | 329 | |
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[100] | 330 | ///Destructor. |
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[209] | 331 | ~Dfs() |
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[100] | 332 | { |
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| 333 | if(local_pred) delete _pred; |
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| 334 | if(local_dist) delete _dist; |
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| 335 | if(local_reached) delete _reached; |
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| 336 | if(local_processed) delete _processed; |
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| 337 | } |
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| 338 | |
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[244] | 339 | ///Sets the map that stores the predecessor arcs. |
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[100] | 340 | |
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[244] | 341 | ///Sets the map that stores the predecessor arcs. |
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[100] | 342 | ///If you don't use this function before calling \ref run(), |
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[244] | 343 | ///it will allocate one. The destructor deallocates this |
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[100] | 344 | ///automatically allocated map, of course. |
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| 345 | ///\return <tt> (*this) </tt> |
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[209] | 346 | Dfs &predMap(PredMap &m) |
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[100] | 347 | { |
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| 348 | if(local_pred) { |
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[209] | 349 | delete _pred; |
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| 350 | local_pred=false; |
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[100] | 351 | } |
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| 352 | _pred = &m; |
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| 353 | return *this; |
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| 354 | } |
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| 355 | |
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[244] | 356 | ///Sets the map that indicates which nodes are reached. |
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[100] | 357 | |
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[244] | 358 | ///Sets the map that indicates which nodes are reached. |
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[100] | 359 | ///If you don't use this function before calling \ref run(), |
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[244] | 360 | ///it will allocate one. The destructor deallocates this |
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| 361 | ///automatically allocated map, of course. |
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| 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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| 376 | ///If you don't use this function before calling \ref run(), |
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| 377 | ///it will allocate one. The destructor deallocates this |
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| 378 | ///automatically allocated map, of course. |
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| 379 | ///\return <tt> (*this) </tt> |
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| 380 | Dfs &processedMap(ProcessedMap &m) |
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| 381 | { |
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| 382 | if(local_processed) { |
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| 383 | delete _processed; |
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| 384 | local_processed=false; |
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| 385 | } |
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| 386 | _processed = &m; |
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| 387 | return *this; |
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| 388 | } |
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| 389 | |
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| 390 | ///Sets the map that stores the distances of the nodes. |
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| 391 | |
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| 392 | ///Sets the map that stores the distances of the nodes calculated by |
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| 393 | ///the algorithm. |
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| 394 | ///If you don't use this function before calling \ref run(), |
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| 395 | ///it will allocate one. The destructor deallocates this |
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[100] | 396 | ///automatically allocated map, of course. |
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| 397 | ///\return <tt> (*this) </tt> |
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[209] | 398 | Dfs &distMap(DistMap &m) |
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[100] | 399 | { |
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| 400 | if(local_dist) { |
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[209] | 401 | delete _dist; |
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| 402 | local_dist=false; |
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[100] | 403 | } |
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| 404 | _dist = &m; |
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| 405 | return *this; |
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| 406 | } |
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| 407 | |
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[244] | 408 | public: |
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[100] | 409 | |
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| 410 | ///\name Execution control |
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| 411 | ///The simplest way to execute the algorithm is to use |
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[244] | 412 | ///one of the member functions called \ref lemon::Dfs::run() "run()". |
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[100] | 413 | ///\n |
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[244] | 414 | ///If you need more control on the execution, first you must call |
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| 415 | ///\ref lemon::Dfs::init() "init()", then you can add a source node |
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| 416 | ///with \ref lemon::Dfs::addSource() "addSource()". |
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| 417 | ///Finally \ref lemon::Dfs::start() "start()" will perform the |
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| 418 | ///actual path computation. |
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[100] | 419 | |
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| 420 | ///@{ |
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| 421 | |
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| 422 | ///Initializes the internal data structures. |
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| 423 | |
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| 424 | ///Initializes the internal data structures. |
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| 425 | /// |
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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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[244] | 442 | ///\pre The stack must be empty. (Otherwise the algorithm gives |
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| 443 | ///false results.) |
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| 444 | /// |
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| 445 | ///\warning Distances will be wrong (or at least strange) in case of |
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| 446 | ///multiple sources. |
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[100] | 447 | void addSource(Node s) |
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| 448 | { |
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[244] | 449 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
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[100] | 450 | if(!(*_reached)[s]) |
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[209] | 451 | { |
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| 452 | _reached->set(s,true); |
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| 453 | _pred->set(s,INVALID); |
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| 454 | OutArcIt e(*G,s); |
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| 455 | if(e!=INVALID) { |
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| 456 | _stack[++_stack_head]=e; |
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| 457 | _dist->set(s,_stack_head); |
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| 458 | } |
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| 459 | else { |
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| 460 | _processed->set(s,true); |
---|
| 461 | _dist->set(s,0); |
---|
| 462 | } |
---|
| 463 | } |
---|
[100] | 464 | } |
---|
[209] | 465 | |
---|
[100] | 466 | ///Processes the next arc. |
---|
| 467 | |
---|
| 468 | ///Processes the next arc. |
---|
| 469 | /// |
---|
| 470 | ///\return The processed arc. |
---|
| 471 | /// |
---|
[244] | 472 | ///\pre The stack must not be empty. |
---|
[100] | 473 | Arc processNextArc() |
---|
[209] | 474 | { |
---|
[100] | 475 | Node m; |
---|
| 476 | Arc e=_stack[_stack_head]; |
---|
| 477 | if(!(*_reached)[m=G->target(e)]) { |
---|
[209] | 478 | _pred->set(m,e); |
---|
| 479 | _reached->set(m,true); |
---|
| 480 | ++_stack_head; |
---|
| 481 | _stack[_stack_head] = OutArcIt(*G, m); |
---|
| 482 | _dist->set(m,_stack_head); |
---|
[100] | 483 | } |
---|
| 484 | else { |
---|
[209] | 485 | m=G->source(e); |
---|
| 486 | ++_stack[_stack_head]; |
---|
[100] | 487 | } |
---|
| 488 | while(_stack_head>=0 && _stack[_stack_head]==INVALID) { |
---|
[209] | 489 | _processed->set(m,true); |
---|
| 490 | --_stack_head; |
---|
| 491 | if(_stack_head>=0) { |
---|
| 492 | m=G->source(_stack[_stack_head]); |
---|
| 493 | ++_stack[_stack_head]; |
---|
| 494 | } |
---|
[100] | 495 | } |
---|
| 496 | return e; |
---|
| 497 | } |
---|
[244] | 498 | |
---|
[100] | 499 | ///Next arc to be processed. |
---|
| 500 | |
---|
| 501 | ///Next arc to be processed. |
---|
| 502 | /// |
---|
[244] | 503 | ///\return The next arc to be processed or \c INVALID if the stack |
---|
| 504 | ///is empty. |
---|
| 505 | OutArcIt nextArc() const |
---|
[209] | 506 | { |
---|
[100] | 507 | return _stack_head>=0?_stack[_stack_head]:INVALID; |
---|
| 508 | } |
---|
| 509 | |
---|
| 510 | ///\brief Returns \c false if there are nodes |
---|
[244] | 511 | ///to be processed. |
---|
[100] | 512 | /// |
---|
| 513 | ///Returns \c false if there are nodes |
---|
[244] | 514 | ///to be processed in the queue (stack). |
---|
| 515 | bool emptyQueue() const { return _stack_head<0; } |
---|
| 516 | |
---|
[100] | 517 | ///Returns the number of the nodes to be processed. |
---|
[209] | 518 | |
---|
[244] | 519 | ///Returns the number of the nodes to be processed in the queue (stack). |
---|
| 520 | int queueSize() const { return _stack_head+1; } |
---|
[209] | 521 | |
---|
[100] | 522 | ///Executes the algorithm. |
---|
| 523 | |
---|
| 524 | ///Executes the algorithm. |
---|
| 525 | /// |
---|
[244] | 526 | ///This method runs the %DFS algorithm from the root node |
---|
| 527 | ///in order to compute the DFS path to each node. |
---|
[100] | 528 | /// |
---|
[244] | 529 | /// The algorithm computes |
---|
| 530 | ///- the %DFS tree, |
---|
| 531 | ///- the distance of each node from the root in the %DFS tree. |
---|
[100] | 532 | /// |
---|
[244] | 533 | ///\pre init() must be called and a root node should be |
---|
| 534 | ///added with addSource() before using this function. |
---|
| 535 | /// |
---|
| 536 | ///\note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
| 537 | ///\code |
---|
| 538 | /// while ( !d.emptyQueue() ) { |
---|
| 539 | /// d.processNextArc(); |
---|
| 540 | /// } |
---|
| 541 | ///\endcode |
---|
[100] | 542 | void start() |
---|
| 543 | { |
---|
| 544 | while ( !emptyQueue() ) processNextArc(); |
---|
| 545 | } |
---|
[209] | 546 | |
---|
[244] | 547 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 548 | |
---|
[244] | 549 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 550 | /// |
---|
[244] | 551 | ///This method runs the %DFS algorithm from the root node |
---|
[286] | 552 | ///in order to compute the DFS path to \c t. |
---|
[100] | 553 | /// |
---|
[244] | 554 | ///The algorithm computes |
---|
[286] | 555 | ///- the %DFS path to \c t, |
---|
| 556 | ///- the distance of \c t from the root in the %DFS tree. |
---|
[100] | 557 | /// |
---|
[244] | 558 | ///\pre init() must be called and a root node should be |
---|
| 559 | ///added with addSource() before using this function. |
---|
[286] | 560 | void start(Node t) |
---|
[100] | 561 | { |
---|
[286] | 562 | while ( !emptyQueue() && G->target(_stack[_stack_head])!=t ) |
---|
[209] | 563 | processNextArc(); |
---|
[100] | 564 | } |
---|
[209] | 565 | |
---|
[100] | 566 | ///Executes the algorithm until a condition is met. |
---|
| 567 | |
---|
| 568 | ///Executes the algorithm until a condition is met. |
---|
| 569 | /// |
---|
[244] | 570 | ///This method runs the %DFS algorithm from the root node |
---|
| 571 | ///until an arc \c a with <tt>am[a]</tt> true is found. |
---|
[100] | 572 | /// |
---|
[244] | 573 | ///\param am A \c bool (or convertible) arc map. The algorithm |
---|
| 574 | ///will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
---|
[100] | 575 | /// |
---|
[244] | 576 | ///\return The reached arc \c a with <tt>am[a]</tt> true or |
---|
[100] | 577 | ///\c INVALID if no such arc was found. |
---|
| 578 | /// |
---|
[244] | 579 | ///\pre init() must be called and a root node should be |
---|
| 580 | ///added with addSource() before using this function. |
---|
| 581 | /// |
---|
| 582 | ///\warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
---|
[100] | 583 | ///not a node map. |
---|
[244] | 584 | template<class ArcBoolMap> |
---|
| 585 | Arc start(const ArcBoolMap &am) |
---|
[100] | 586 | { |
---|
[244] | 587 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
---|
[100] | 588 | processNextArc(); |
---|
| 589 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
| 590 | } |
---|
| 591 | |
---|
[286] | 592 | ///Runs the algorithm from the given source node. |
---|
[209] | 593 | |
---|
[244] | 594 | ///This method runs the %DFS algorithm from node \c s |
---|
| 595 | ///in order to compute the DFS path to each node. |
---|
[100] | 596 | /// |
---|
[244] | 597 | ///The algorithm computes |
---|
| 598 | ///- the %DFS tree, |
---|
| 599 | ///- the distance of each node from the root in the %DFS tree. |
---|
| 600 | /// |
---|
| 601 | ///\note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 602 | ///\code |
---|
| 603 | /// d.init(); |
---|
[244] | 604 | /// d.addSource(s); |
---|
| 605 | /// d.start(); |
---|
| 606 | ///\endcode |
---|
| 607 | void run(Node s) { |
---|
| 608 | init(); |
---|
| 609 | addSource(s); |
---|
| 610 | start(); |
---|
| 611 | } |
---|
| 612 | |
---|
| 613 | ///Finds the %DFS path between \c s and \c t. |
---|
| 614 | |
---|
| 615 | ///This method runs the %DFS algorithm from node \c s |
---|
[286] | 616 | ///in order to compute the DFS path to node \c t |
---|
| 617 | ///(it stops searching when \c t is processed) |
---|
[244] | 618 | /// |
---|
[286] | 619 | ///\return \c true if \c t is reachable form \c s. |
---|
[244] | 620 | /// |
---|
| 621 | ///\note Apart from the return value, <tt>d.run(s,t)</tt> is |
---|
| 622 | ///just a shortcut of the following code. |
---|
| 623 | ///\code |
---|
| 624 | /// d.init(); |
---|
| 625 | /// d.addSource(s); |
---|
| 626 | /// d.start(t); |
---|
| 627 | ///\endcode |
---|
[286] | 628 | bool run(Node s,Node t) { |
---|
[244] | 629 | init(); |
---|
| 630 | addSource(s); |
---|
| 631 | start(t); |
---|
[286] | 632 | return reached(t); |
---|
[244] | 633 | } |
---|
| 634 | |
---|
| 635 | ///Runs the algorithm to visit all nodes in the digraph. |
---|
| 636 | |
---|
| 637 | ///This method runs the %DFS algorithm in order to compute the |
---|
| 638 | ///%DFS path to each node. |
---|
| 639 | /// |
---|
| 640 | ///The algorithm computes |
---|
| 641 | ///- the %DFS tree, |
---|
| 642 | ///- the distance of each node from the root in the %DFS tree. |
---|
| 643 | /// |
---|
| 644 | ///\note <tt>d.run()</tt> is just a shortcut of the following code. |
---|
| 645 | ///\code |
---|
| 646 | /// d.init(); |
---|
| 647 | /// for (NodeIt n(digraph); n != INVALID; ++n) { |
---|
| 648 | /// if (!d.reached(n)) { |
---|
| 649 | /// d.addSource(n); |
---|
[100] | 650 | /// d.start(); |
---|
| 651 | /// } |
---|
| 652 | /// } |
---|
| 653 | ///\endcode |
---|
| 654 | void run() { |
---|
| 655 | init(); |
---|
| 656 | for (NodeIt it(*G); it != INVALID; ++it) { |
---|
| 657 | if (!reached(it)) { |
---|
| 658 | addSource(it); |
---|
| 659 | start(); |
---|
| 660 | } |
---|
| 661 | } |
---|
| 662 | } |
---|
| 663 | |
---|
| 664 | ///@} |
---|
| 665 | |
---|
| 666 | ///\name Query Functions |
---|
| 667 | ///The result of the %DFS algorithm can be obtained using these |
---|
| 668 | ///functions.\n |
---|
[244] | 669 | ///Either \ref lemon::Dfs::run() "run()" or \ref lemon::Dfs::start() |
---|
| 670 | ///"start()" must be called before using them. |
---|
[209] | 671 | |
---|
[100] | 672 | ///@{ |
---|
| 673 | |
---|
[244] | 674 | ///The DFS path to a node. |
---|
[100] | 675 | |
---|
[244] | 676 | ///Returns the DFS path to a node. |
---|
| 677 | /// |
---|
| 678 | ///\warning \c t should be reachable from the root. |
---|
| 679 | /// |
---|
| 680 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 681 | ///using this function. |
---|
| 682 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
[209] | 683 | |
---|
[244] | 684 | ///The distance of a node from the root. |
---|
[100] | 685 | |
---|
[244] | 686 | ///Returns the distance of a node from the root. |
---|
| 687 | /// |
---|
| 688 | ///\warning If node \c v is not reachable from the root, then |
---|
| 689 | ///the return value of this function is undefined. |
---|
| 690 | /// |
---|
| 691 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 692 | ///using this function. |
---|
[100] | 693 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 694 | |
---|
[244] | 695 | ///Returns the 'previous arc' of the %DFS tree for a node. |
---|
[100] | 696 | |
---|
[244] | 697 | ///This function returns the 'previous arc' of the %DFS tree for the |
---|
| 698 | ///node \c v, i.e. it returns the last arc of a %DFS path from the |
---|
| 699 | ///root to \c v. It is \c INVALID |
---|
| 700 | ///if \c v is not reachable from the root(s) or if \c v is a root. |
---|
| 701 | /// |
---|
| 702 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
[100] | 703 | ///\ref predNode(). |
---|
[244] | 704 | /// |
---|
[100] | 705 | ///\pre Either \ref run() or \ref start() must be called before using |
---|
| 706 | ///this function. |
---|
| 707 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 708 | |
---|
| 709 | ///Returns the 'previous node' of the %DFS tree. |
---|
| 710 | |
---|
[244] | 711 | ///This function returns the 'previous node' of the %DFS |
---|
| 712 | ///tree for the node \c v, i.e. it returns the last but one node |
---|
| 713 | ///from a %DFS path from the root to \c v. It is \c INVALID |
---|
| 714 | ///if \c v is not reachable from the root(s) or if \c v is a root. |
---|
| 715 | /// |
---|
| 716 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
| 717 | ///\ref predArc(). |
---|
| 718 | /// |
---|
[100] | 719 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 720 | ///using this function. |
---|
| 721 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
[209] | 722 | G->source((*_pred)[v]); } |
---|
| 723 | |
---|
[244] | 724 | ///\brief Returns a const reference to the node map that stores the |
---|
| 725 | ///distances of the nodes. |
---|
| 726 | /// |
---|
| 727 | ///Returns a const reference to the node map that stores the |
---|
| 728 | ///distances of the nodes calculated by the algorithm. |
---|
| 729 | /// |
---|
| 730 | ///\pre Either \ref run() or \ref init() |
---|
| 731 | ///must be called before using this function. |
---|
[100] | 732 | const DistMap &distMap() const { return *_dist;} |
---|
[209] | 733 | |
---|
[244] | 734 | ///\brief Returns a const reference to the node map that stores the |
---|
| 735 | ///predecessor arcs. |
---|
| 736 | /// |
---|
| 737 | ///Returns a const reference to the node map that stores the predecessor |
---|
| 738 | ///arcs, which form the DFS tree. |
---|
| 739 | /// |
---|
[100] | 740 | ///\pre Either \ref run() or \ref init() |
---|
| 741 | ///must be called before using this function. |
---|
| 742 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 743 | |
---|
[244] | 744 | ///Checks if a node is reachable from the root(s). |
---|
[100] | 745 | |
---|
| 746 | ///Returns \c true if \c v is reachable from the root(s). |
---|
| 747 | ///\pre Either \ref run() or \ref start() |
---|
| 748 | ///must be called before using this function. |
---|
[244] | 749 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[209] | 750 | |
---|
[100] | 751 | ///@} |
---|
| 752 | }; |
---|
| 753 | |
---|
[244] | 754 | ///Default traits class of dfs() function. |
---|
[100] | 755 | |
---|
[244] | 756 | ///Default traits class of dfs() function. |
---|
[157] | 757 | ///\tparam GR Digraph type. |
---|
[100] | 758 | template<class GR> |
---|
| 759 | struct DfsWizardDefaultTraits |
---|
| 760 | { |
---|
[244] | 761 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 762 | typedef GR Digraph; |
---|
[244] | 763 | |
---|
| 764 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 765 | ///arcs of the %DFS paths. |
---|
[209] | 766 | /// |
---|
[244] | 767 | ///The type of the map that stores the predecessor |
---|
[100] | 768 | ///arcs of the %DFS paths. |
---|
| 769 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 770 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
---|
[244] | 771 | ///Instantiates a \ref PredMap. |
---|
[209] | 772 | |
---|
| 773 | ///This function instantiates a \ref PredMap. |
---|
[244] | 774 | ///\param g is the digraph, to which we would like to define the |
---|
| 775 | ///\ref PredMap. |
---|
| 776 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 777 | { |
---|
[278] | 778 | return new PredMap(g); |
---|
[100] | 779 | } |
---|
| 780 | |
---|
| 781 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 782 | |
---|
[100] | 783 | ///The type of the map that indicates which nodes are processed. |
---|
| 784 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 785 | ///By default it is a NullMap. |
---|
[100] | 786 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[244] | 787 | ///Instantiates a \ref ProcessedMap. |
---|
[209] | 788 | |
---|
| 789 | ///This function instantiates a \ref ProcessedMap. |
---|
[100] | 790 | ///\param g is the digraph, to which |
---|
[244] | 791 | ///we would like to define the \ref ProcessedMap. |
---|
[100] | 792 | #ifdef DOXYGEN |
---|
[244] | 793 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 794 | #else |
---|
[244] | 795 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 796 | #endif |
---|
| 797 | { |
---|
| 798 | return new ProcessedMap(); |
---|
| 799 | } |
---|
[244] | 800 | |
---|
[100] | 801 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 802 | |
---|
[100] | 803 | ///The type of the map that indicates which nodes are reached. |
---|
[244] | 804 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 805 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[244] | 806 | ///Instantiates a \ref ReachedMap. |
---|
[209] | 807 | |
---|
| 808 | ///This function instantiates a \ref ReachedMap. |
---|
[244] | 809 | ///\param g is the digraph, to which |
---|
[100] | 810 | ///we would like to define the \ref ReachedMap. |
---|
[244] | 811 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 812 | { |
---|
[244] | 813 | return new ReachedMap(g); |
---|
[100] | 814 | } |
---|
[209] | 815 | |
---|
[244] | 816 | ///The type of the map that stores the distances of the nodes. |
---|
| 817 | |
---|
| 818 | ///The type of the map that stores the distances of the nodes. |
---|
[100] | 819 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 820 | typedef typename Digraph::template NodeMap<int> DistMap; |
---|
[244] | 821 | ///Instantiates a \ref DistMap. |
---|
[209] | 822 | |
---|
| 823 | ///This function instantiates a \ref DistMap. |
---|
[210] | 824 | ///\param g is the digraph, to which we would like to define |
---|
| 825 | ///the \ref DistMap |
---|
[244] | 826 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 827 | { |
---|
[278] | 828 | return new DistMap(g); |
---|
[100] | 829 | } |
---|
[278] | 830 | |
---|
| 831 | ///The type of the DFS paths. |
---|
| 832 | |
---|
| 833 | ///The type of the DFS paths. |
---|
| 834 | ///It must meet the \ref concepts::Path "Path" concept. |
---|
| 835 | typedef lemon::Path<Digraph> Path; |
---|
[100] | 836 | }; |
---|
[209] | 837 | |
---|
[244] | 838 | /// Default traits class used by \ref DfsWizard |
---|
[100] | 839 | |
---|
| 840 | /// To make it easier to use Dfs algorithm |
---|
[244] | 841 | /// we have created a wizard class. |
---|
[100] | 842 | /// This \ref DfsWizard class needs default traits, |
---|
[244] | 843 | /// as well as the \ref Dfs class. |
---|
[100] | 844 | /// The \ref DfsWizardBase is a class to be the default traits of the |
---|
| 845 | /// \ref DfsWizard class. |
---|
| 846 | template<class GR> |
---|
| 847 | class DfsWizardBase : public DfsWizardDefaultTraits<GR> |
---|
| 848 | { |
---|
| 849 | |
---|
| 850 | typedef DfsWizardDefaultTraits<GR> Base; |
---|
| 851 | protected: |
---|
[244] | 852 | //The type of the nodes in the digraph. |
---|
[100] | 853 | typedef typename Base::Digraph::Node Node; |
---|
| 854 | |
---|
[244] | 855 | //Pointer to the digraph the algorithm runs on. |
---|
[100] | 856 | void *_g; |
---|
[244] | 857 | //Pointer to the map of reached nodes. |
---|
[100] | 858 | void *_reached; |
---|
[244] | 859 | //Pointer to the map of processed nodes. |
---|
[100] | 860 | void *_processed; |
---|
[244] | 861 | //Pointer to the map of predecessors arcs. |
---|
[100] | 862 | void *_pred; |
---|
[244] | 863 | //Pointer to the map of distances. |
---|
[100] | 864 | void *_dist; |
---|
[278] | 865 | //Pointer to the DFS path to the target node. |
---|
| 866 | void *_path; |
---|
| 867 | //Pointer to the distance of the target node. |
---|
| 868 | int *_di; |
---|
[209] | 869 | |
---|
[100] | 870 | public: |
---|
| 871 | /// Constructor. |
---|
[209] | 872 | |
---|
[100] | 873 | /// This constructor does not require parameters, therefore it initiates |
---|
[278] | 874 | /// all of the attributes to \c 0. |
---|
[100] | 875 | DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[278] | 876 | _dist(0), _path(0), _di(0) {} |
---|
[100] | 877 | |
---|
| 878 | /// Constructor. |
---|
[209] | 879 | |
---|
[278] | 880 | /// This constructor requires one parameter, |
---|
| 881 | /// others are initiated to \c 0. |
---|
[244] | 882 | /// \param g The digraph the algorithm runs on. |
---|
[278] | 883 | DfsWizardBase(const GR &g) : |
---|
[209] | 884 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
---|
[278] | 885 | _reached(0), _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
---|
[100] | 886 | |
---|
| 887 | }; |
---|
[209] | 888 | |
---|
[278] | 889 | /// Auxiliary class for the function-type interface of DFS algorithm. |
---|
[100] | 890 | |
---|
[278] | 891 | /// This auxiliary class is created to implement the |
---|
| 892 | /// \ref dfs() "function-type interface" of \ref Dfs algorithm. |
---|
| 893 | /// It does not have own \ref run() method, it uses the functions |
---|
| 894 | /// and features of the plain \ref Dfs. |
---|
[100] | 895 | /// |
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[278] | 896 | /// This class should only be used through the \ref dfs() function, |
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| 897 | /// which makes it easier to use the algorithm. |
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[100] | 898 | template<class TR> |
---|
| 899 | class DfsWizard : public TR |
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| 900 | { |
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| 901 | typedef TR Base; |
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| 902 | |
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[244] | 903 | ///The type of the digraph the algorithm runs on. |
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[100] | 904 | typedef typename TR::Digraph Digraph; |
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[244] | 905 | |
---|
[100] | 906 | typedef typename Digraph::Node Node; |
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| 907 | typedef typename Digraph::NodeIt NodeIt; |
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| 908 | typedef typename Digraph::Arc Arc; |
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| 909 | typedef typename Digraph::OutArcIt OutArcIt; |
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[209] | 910 | |
---|
[244] | 911 | ///\brief The type of the map that stores the predecessor |
---|
[278] | 912 | ///arcs of the DFS paths. |
---|
[244] | 913 | typedef typename TR::PredMap PredMap; |
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| 914 | ///\brief The type of the map that stores the distances of the nodes. |
---|
| 915 | typedef typename TR::DistMap DistMap; |
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| 916 | ///\brief The type of the map that indicates which nodes are reached. |
---|
[100] | 917 | typedef typename TR::ReachedMap ReachedMap; |
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[244] | 918 | ///\brief The type of the map that indicates which nodes are processed. |
---|
[100] | 919 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
[278] | 920 | ///The type of the DFS paths |
---|
| 921 | typedef typename TR::Path Path; |
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[100] | 922 | |
---|
| 923 | public: |
---|
[244] | 924 | |
---|
[100] | 925 | /// Constructor. |
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| 926 | DfsWizard() : TR() {} |
---|
| 927 | |
---|
| 928 | /// Constructor that requires parameters. |
---|
| 929 | |
---|
| 930 | /// Constructor that requires parameters. |
---|
| 931 | /// These parameters will be the default values for the traits class. |
---|
[278] | 932 | /// \param g The digraph the algorithm runs on. |
---|
| 933 | DfsWizard(const Digraph &g) : |
---|
| 934 | TR(g) {} |
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[100] | 935 | |
---|
| 936 | ///Copy constructor |
---|
| 937 | DfsWizard(const TR &b) : TR(b) {} |
---|
| 938 | |
---|
| 939 | ~DfsWizard() {} |
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| 940 | |
---|
[278] | 941 | ///Runs DFS algorithm from the given source node. |
---|
[209] | 942 | |
---|
[278] | 943 | ///This method runs DFS algorithm from node \c s |
---|
| 944 | ///in order to compute the DFS path to each node. |
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| 945 | void run(Node s) |
---|
| 946 | { |
---|
| 947 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 948 | if (Base::_pred) |
---|
| 949 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 950 | if (Base::_dist) |
---|
| 951 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 952 | if (Base::_reached) |
---|
| 953 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
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| 954 | if (Base::_processed) |
---|
| 955 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 956 | if (s!=INVALID) |
---|
| 957 | alg.run(s); |
---|
| 958 | else |
---|
| 959 | alg.run(); |
---|
| 960 | } |
---|
| 961 | |
---|
| 962 | ///Finds the DFS path between \c s and \c t. |
---|
| 963 | |
---|
| 964 | ///This method runs DFS algorithm from node \c s |
---|
| 965 | ///in order to compute the DFS path to node \c t |
---|
| 966 | ///(it stops searching when \c t is processed). |
---|
| 967 | /// |
---|
| 968 | ///\return \c true if \c t is reachable form \c s. |
---|
| 969 | bool run(Node s, Node t) |
---|
| 970 | { |
---|
| 971 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 972 | if (Base::_pred) |
---|
| 973 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 974 | if (Base::_dist) |
---|
| 975 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 976 | if (Base::_reached) |
---|
| 977 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 978 | if (Base::_processed) |
---|
| 979 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 980 | alg.run(s,t); |
---|
| 981 | if (Base::_path) |
---|
| 982 | *reinterpret_cast<Path*>(Base::_path) = alg.path(t); |
---|
| 983 | if (Base::_di) |
---|
| 984 | *Base::_di = alg.dist(t); |
---|
| 985 | return alg.reached(t); |
---|
| 986 | } |
---|
| 987 | |
---|
| 988 | ///Runs DFS algorithm to visit all nodes in the digraph. |
---|
| 989 | |
---|
| 990 | ///This method runs DFS algorithm in order to compute |
---|
| 991 | ///the DFS path to each node. |
---|
[100] | 992 | void run() |
---|
| 993 | { |
---|
[278] | 994 | run(INVALID); |
---|
[244] | 995 | } |
---|
| 996 | |
---|
[100] | 997 | template<class T> |
---|
[257] | 998 | struct SetPredMapBase : public Base { |
---|
[100] | 999 | typedef T PredMap; |
---|
| 1000 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
[257] | 1001 | SetPredMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1002 | }; |
---|
[278] | 1003 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1004 | ///for setting \ref PredMap object. |
---|
[100] | 1005 | /// |
---|
[278] | 1006 | ///\ref named-func-param "Named parameter" |
---|
[244] | 1007 | ///for setting \ref PredMap object. |
---|
[100] | 1008 | template<class T> |
---|
[257] | 1009 | DfsWizard<SetPredMapBase<T> > predMap(const T &t) |
---|
[100] | 1010 | { |
---|
| 1011 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1012 | return DfsWizard<SetPredMapBase<T> >(*this); |
---|
[100] | 1013 | } |
---|
[209] | 1014 | |
---|
[100] | 1015 | template<class T> |
---|
[257] | 1016 | struct SetReachedMapBase : public Base { |
---|
[100] | 1017 | typedef T ReachedMap; |
---|
| 1018 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
[257] | 1019 | SetReachedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1020 | }; |
---|
[278] | 1021 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1022 | ///for setting \ref ReachedMap object. |
---|
[100] | 1023 | /// |
---|
[278] | 1024 | /// \ref named-func-param "Named parameter" |
---|
[244] | 1025 | ///for setting \ref ReachedMap object. |
---|
[100] | 1026 | template<class T> |
---|
[257] | 1027 | DfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
---|
[100] | 1028 | { |
---|
[158] | 1029 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1030 | return DfsWizard<SetReachedMapBase<T> >(*this); |
---|
[100] | 1031 | } |
---|
[209] | 1032 | |
---|
[100] | 1033 | template<class T> |
---|
[278] | 1034 | struct SetDistMapBase : public Base { |
---|
| 1035 | typedef T DistMap; |
---|
| 1036 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
| 1037 | SetDistMapBase(const TR &b) : TR(b) {} |
---|
| 1038 | }; |
---|
| 1039 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1040 | ///for setting \ref DistMap object. |
---|
| 1041 | /// |
---|
| 1042 | /// \ref named-func-param "Named parameter" |
---|
| 1043 | ///for setting \ref DistMap object. |
---|
| 1044 | template<class T> |
---|
| 1045 | DfsWizard<SetDistMapBase<T> > distMap(const T &t) |
---|
| 1046 | { |
---|
| 1047 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1048 | return DfsWizard<SetDistMapBase<T> >(*this); |
---|
| 1049 | } |
---|
| 1050 | |
---|
| 1051 | template<class T> |
---|
[257] | 1052 | struct SetProcessedMapBase : public Base { |
---|
[100] | 1053 | typedef T ProcessedMap; |
---|
| 1054 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
[257] | 1055 | SetProcessedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1056 | }; |
---|
[278] | 1057 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1058 | ///for setting \ref ProcessedMap object. |
---|
[100] | 1059 | /// |
---|
[278] | 1060 | /// \ref named-func-param "Named parameter" |
---|
[244] | 1061 | ///for setting \ref ProcessedMap object. |
---|
[100] | 1062 | template<class T> |
---|
[257] | 1063 | DfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
---|
[100] | 1064 | { |
---|
[158] | 1065 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1066 | return DfsWizard<SetProcessedMapBase<T> >(*this); |
---|
[100] | 1067 | } |
---|
[209] | 1068 | |
---|
[100] | 1069 | template<class T> |
---|
[278] | 1070 | struct SetPathBase : public Base { |
---|
| 1071 | typedef T Path; |
---|
| 1072 | SetPathBase(const TR &b) : TR(b) {} |
---|
[100] | 1073 | }; |
---|
[278] | 1074 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1075 | ///for getting the DFS path to the target node. |
---|
[100] | 1076 | /// |
---|
[278] | 1077 | ///\ref named-func-param "Named parameter" |
---|
| 1078 | ///for getting the DFS path to the target node. |
---|
[100] | 1079 | template<class T> |
---|
[278] | 1080 | DfsWizard<SetPathBase<T> > path(const T &t) |
---|
[100] | 1081 | { |
---|
[278] | 1082 | Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1083 | return DfsWizard<SetPathBase<T> >(*this); |
---|
| 1084 | } |
---|
| 1085 | |
---|
| 1086 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1087 | ///for getting the distance of the target node. |
---|
| 1088 | /// |
---|
| 1089 | ///\ref named-func-param "Named parameter" |
---|
| 1090 | ///for getting the distance of the target node. |
---|
| 1091 | DfsWizard dist(const int &d) |
---|
| 1092 | { |
---|
| 1093 | Base::_di=const_cast<int*>(&d); |
---|
| 1094 | return *this; |
---|
[100] | 1095 | } |
---|
[209] | 1096 | |
---|
[100] | 1097 | }; |
---|
[209] | 1098 | |
---|
[278] | 1099 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1100 | |
---|
| 1101 | ///\ingroup search |
---|
[278] | 1102 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1103 | /// |
---|
[278] | 1104 | ///This function also has several \ref named-func-param "named parameters", |
---|
[100] | 1105 | ///they are declared as the members of class \ref DfsWizard. |
---|
[278] | 1106 | ///The following examples show how to use these parameters. |
---|
[100] | 1107 | ///\code |
---|
[278] | 1108 | /// // Compute the DFS tree |
---|
| 1109 | /// dfs(g).predMap(preds).distMap(dists).run(s); |
---|
| 1110 | /// |
---|
| 1111 | /// // Compute the DFS path from s to t |
---|
| 1112 | /// bool reached = dfs(g).path(p).dist(d).run(s,t); |
---|
[100] | 1113 | ///\endcode |
---|
[278] | 1114 | |
---|
[100] | 1115 | ///\warning Don't forget to put the \ref DfsWizard::run() "run()" |
---|
| 1116 | ///to the end of the parameter list. |
---|
| 1117 | ///\sa DfsWizard |
---|
| 1118 | ///\sa Dfs |
---|
| 1119 | template<class GR> |
---|
| 1120 | DfsWizard<DfsWizardBase<GR> > |
---|
[278] | 1121 | dfs(const GR &digraph) |
---|
[100] | 1122 | { |
---|
[278] | 1123 | return DfsWizard<DfsWizardBase<GR> >(digraph); |
---|
[100] | 1124 | } |
---|
| 1125 | |
---|
| 1126 | #ifdef DOXYGEN |
---|
[244] | 1127 | /// \brief Visitor class for DFS. |
---|
[209] | 1128 | /// |
---|
[244] | 1129 | /// This class defines the interface of the DfsVisit events, and |
---|
| 1130 | /// it could be the base of a real visitor class. |
---|
[100] | 1131 | template <typename _Digraph> |
---|
| 1132 | struct DfsVisitor { |
---|
| 1133 | typedef _Digraph Digraph; |
---|
| 1134 | typedef typename Digraph::Arc Arc; |
---|
| 1135 | typedef typename Digraph::Node Node; |
---|
[244] | 1136 | /// \brief Called for the source node of the DFS. |
---|
[209] | 1137 | /// |
---|
[244] | 1138 | /// This function is called for the source node of the DFS. |
---|
| 1139 | void start(const Node& node) {} |
---|
| 1140 | /// \brief Called when the source node is leaved. |
---|
| 1141 | /// |
---|
| 1142 | /// This function is called when the source node is leaved. |
---|
| 1143 | void stop(const Node& node) {} |
---|
| 1144 | /// \brief Called when a node is reached first time. |
---|
| 1145 | /// |
---|
| 1146 | /// This function is called when a node is reached first time. |
---|
| 1147 | void reach(const Node& node) {} |
---|
| 1148 | /// \brief Called when an arc reaches a new node. |
---|
| 1149 | /// |
---|
| 1150 | /// This function is called when the DFS finds an arc whose target node |
---|
| 1151 | /// is not reached yet. |
---|
[100] | 1152 | void discover(const Arc& arc) {} |
---|
[244] | 1153 | /// \brief Called when an arc is examined but its target node is |
---|
[100] | 1154 | /// already discovered. |
---|
[209] | 1155 | /// |
---|
[244] | 1156 | /// This function is called when an arc is examined but its target node is |
---|
[100] | 1157 | /// already discovered. |
---|
| 1158 | void examine(const Arc& arc) {} |
---|
[244] | 1159 | /// \brief Called when the DFS steps back from a node. |
---|
[209] | 1160 | /// |
---|
[244] | 1161 | /// This function is called when the DFS steps back from a node. |
---|
| 1162 | void leave(const Node& node) {} |
---|
| 1163 | /// \brief Called when the DFS steps back on an arc. |
---|
[209] | 1164 | /// |
---|
[244] | 1165 | /// This function is called when the DFS steps back on an arc. |
---|
| 1166 | void backtrack(const Arc& arc) {} |
---|
[100] | 1167 | }; |
---|
| 1168 | #else |
---|
| 1169 | template <typename _Digraph> |
---|
| 1170 | struct DfsVisitor { |
---|
| 1171 | typedef _Digraph Digraph; |
---|
| 1172 | typedef typename Digraph::Arc Arc; |
---|
| 1173 | typedef typename Digraph::Node Node; |
---|
| 1174 | void start(const Node&) {} |
---|
| 1175 | void stop(const Node&) {} |
---|
[244] | 1176 | void reach(const Node&) {} |
---|
| 1177 | void discover(const Arc&) {} |
---|
| 1178 | void examine(const Arc&) {} |
---|
| 1179 | void leave(const Node&) {} |
---|
| 1180 | void backtrack(const Arc&) {} |
---|
[100] | 1181 | |
---|
| 1182 | template <typename _Visitor> |
---|
| 1183 | struct Constraints { |
---|
| 1184 | void constraints() { |
---|
[209] | 1185 | Arc arc; |
---|
| 1186 | Node node; |
---|
| 1187 | visitor.start(node); |
---|
| 1188 | visitor.stop(arc); |
---|
[244] | 1189 | visitor.reach(node); |
---|
| 1190 | visitor.discover(arc); |
---|
| 1191 | visitor.examine(arc); |
---|
| 1192 | visitor.leave(node); |
---|
| 1193 | visitor.backtrack(arc); |
---|
[100] | 1194 | } |
---|
| 1195 | _Visitor& visitor; |
---|
| 1196 | }; |
---|
| 1197 | }; |
---|
| 1198 | #endif |
---|
| 1199 | |
---|
| 1200 | /// \brief Default traits class of DfsVisit class. |
---|
| 1201 | /// |
---|
| 1202 | /// Default traits class of DfsVisit class. |
---|
[244] | 1203 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[100] | 1204 | template<class _Digraph> |
---|
| 1205 | struct DfsVisitDefaultTraits { |
---|
| 1206 | |
---|
[244] | 1207 | /// \brief The type of the digraph the algorithm runs on. |
---|
[100] | 1208 | typedef _Digraph Digraph; |
---|
| 1209 | |
---|
| 1210 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1211 | /// |
---|
[100] | 1212 | /// The type of the map that indicates which nodes are reached. |
---|
[244] | 1213 | /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 1214 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1215 | |
---|
[244] | 1216 | /// \brief Instantiates a \ref ReachedMap. |
---|
[100] | 1217 | /// |
---|
[209] | 1218 | /// This function instantiates a \ref ReachedMap. |
---|
[100] | 1219 | /// \param digraph is the digraph, to which |
---|
| 1220 | /// we would like to define the \ref ReachedMap. |
---|
| 1221 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1222 | return new ReachedMap(digraph); |
---|
| 1223 | } |
---|
| 1224 | |
---|
| 1225 | }; |
---|
[209] | 1226 | |
---|
[100] | 1227 | /// \ingroup search |
---|
[244] | 1228 | /// |
---|
| 1229 | /// \brief %DFS algorithm class with visitor interface. |
---|
| 1230 | /// |
---|
[100] | 1231 | /// This class provides an efficient implementation of the %DFS algorithm |
---|
| 1232 | /// with visitor interface. |
---|
| 1233 | /// |
---|
| 1234 | /// The %DfsVisit class provides an alternative interface to the Dfs |
---|
| 1235 | /// class. It works with callback mechanism, the DfsVisit object calls |
---|
[244] | 1236 | /// the member functions of the \c Visitor class on every DFS event. |
---|
[100] | 1237 | /// |
---|
[252] | 1238 | /// This interface of the DFS algorithm should be used in special cases |
---|
| 1239 | /// when extra actions have to be performed in connection with certain |
---|
| 1240 | /// events of the DFS algorithm. Otherwise consider to use Dfs or dfs() |
---|
| 1241 | /// instead. |
---|
| 1242 | /// |
---|
[244] | 1243 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[210] | 1244 | /// The default value is |
---|
[244] | 1245 | /// \ref ListDigraph. The value of _Digraph is not used directly by |
---|
| 1246 | /// \ref DfsVisit, it is only passed to \ref DfsVisitDefaultTraits. |
---|
| 1247 | /// \tparam _Visitor The Visitor type that is used by the algorithm. |
---|
| 1248 | /// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty visitor, which |
---|
| 1249 | /// does not observe the DFS events. If you want to observe the DFS |
---|
| 1250 | /// events, you should implement your own visitor class. |
---|
[209] | 1251 | /// \tparam _Traits Traits class to set various data types used by the |
---|
[100] | 1252 | /// algorithm. The default traits class is |
---|
| 1253 | /// \ref DfsVisitDefaultTraits "DfsVisitDefaultTraits<_Digraph>". |
---|
| 1254 | /// See \ref DfsVisitDefaultTraits for the documentation of |
---|
[244] | 1255 | /// a DFS visit traits class. |
---|
[100] | 1256 | #ifdef DOXYGEN |
---|
| 1257 | template <typename _Digraph, typename _Visitor, typename _Traits> |
---|
| 1258 | #else |
---|
| 1259 | template <typename _Digraph = ListDigraph, |
---|
[209] | 1260 | typename _Visitor = DfsVisitor<_Digraph>, |
---|
[288] | 1261 | typename _Traits = DfsVisitDefaultTraits<_Digraph> > |
---|
[100] | 1262 | #endif |
---|
| 1263 | class DfsVisit { |
---|
| 1264 | public: |
---|
[209] | 1265 | |
---|
[244] | 1266 | ///The traits class. |
---|
[100] | 1267 | typedef _Traits Traits; |
---|
| 1268 | |
---|
[244] | 1269 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 1270 | typedef typename Traits::Digraph Digraph; |
---|
| 1271 | |
---|
[244] | 1272 | ///The visitor type used by the algorithm. |
---|
[100] | 1273 | typedef _Visitor Visitor; |
---|
| 1274 | |
---|
[244] | 1275 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 1276 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1277 | |
---|
| 1278 | private: |
---|
| 1279 | |
---|
| 1280 | typedef typename Digraph::Node Node; |
---|
| 1281 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1282 | typedef typename Digraph::Arc Arc; |
---|
| 1283 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1284 | |
---|
[244] | 1285 | //Pointer to the underlying digraph. |
---|
[100] | 1286 | const Digraph *_digraph; |
---|
[244] | 1287 | //Pointer to the visitor object. |
---|
[100] | 1288 | Visitor *_visitor; |
---|
[244] | 1289 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 1290 | ReachedMap *_reached; |
---|
[244] | 1291 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 1292 | bool local_reached; |
---|
| 1293 | |
---|
| 1294 | std::vector<typename Digraph::Arc> _stack; |
---|
| 1295 | int _stack_head; |
---|
| 1296 | |
---|
[280] | 1297 | //Creates the maps if necessary. |
---|
[100] | 1298 | void create_maps() { |
---|
| 1299 | if(!_reached) { |
---|
[209] | 1300 | local_reached = true; |
---|
| 1301 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1302 | } |
---|
| 1303 | } |
---|
| 1304 | |
---|
| 1305 | protected: |
---|
| 1306 | |
---|
| 1307 | DfsVisit() {} |
---|
[209] | 1308 | |
---|
[100] | 1309 | public: |
---|
| 1310 | |
---|
| 1311 | typedef DfsVisit Create; |
---|
| 1312 | |
---|
| 1313 | /// \name Named template parameters |
---|
| 1314 | |
---|
| 1315 | ///@{ |
---|
| 1316 | template <class T> |
---|
[257] | 1317 | struct SetReachedMapTraits : public Traits { |
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[100] | 1318 | typedef T ReachedMap; |
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| 1319 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
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[290] | 1320 | LEMON_ASSERT(false, "ReachedMap is not initialized"); |
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| 1321 | return 0; // ignore warnings |
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[100] | 1322 | } |
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| 1323 | }; |
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[209] | 1324 | /// \brief \ref named-templ-param "Named parameter" for setting |
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[244] | 1325 | /// ReachedMap type. |
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[100] | 1326 | /// |
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[244] | 1327 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
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[100] | 1328 | template <class T> |
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[257] | 1329 | struct SetReachedMap : public DfsVisit< Digraph, Visitor, |
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| 1330 | SetReachedMapTraits<T> > { |
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| 1331 | typedef DfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
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[100] | 1332 | }; |
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| 1333 | ///@} |
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| 1334 | |
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[209] | 1335 | public: |
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| 1336 | |
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[100] | 1337 | /// \brief Constructor. |
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| 1338 | /// |
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| 1339 | /// Constructor. |
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| 1340 | /// |
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[244] | 1341 | /// \param digraph The digraph the algorithm runs on. |
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| 1342 | /// \param visitor The visitor object of the algorithm. |
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[209] | 1343 | DfsVisit(const Digraph& digraph, Visitor& visitor) |
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[100] | 1344 | : _digraph(&digraph), _visitor(&visitor), |
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[209] | 1345 | _reached(0), local_reached(false) {} |
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| 1346 | |
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[100] | 1347 | /// \brief Destructor. |
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| 1348 | ~DfsVisit() { |
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| 1349 | if(local_reached) delete _reached; |
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| 1350 | } |
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| 1351 | |
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[244] | 1352 | /// \brief Sets the map that indicates which nodes are reached. |
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[100] | 1353 | /// |
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[244] | 1354 | /// Sets the map that indicates which nodes are reached. |
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[100] | 1355 | /// If you don't use this function before calling \ref run(), |
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[244] | 1356 | /// it will allocate one. The destructor deallocates this |
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[100] | 1357 | /// automatically allocated map, of course. |
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| 1358 | /// \return <tt> (*this) </tt> |
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| 1359 | DfsVisit &reachedMap(ReachedMap &m) { |
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| 1360 | if(local_reached) { |
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[209] | 1361 | delete _reached; |
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| 1362 | local_reached=false; |
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[100] | 1363 | } |
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| 1364 | _reached = &m; |
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| 1365 | return *this; |
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| 1366 | } |
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| 1367 | |
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| 1368 | public: |
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[244] | 1369 | |
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[100] | 1370 | /// \name Execution control |
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| 1371 | /// The simplest way to execute the algorithm is to use |
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[244] | 1372 | /// one of the member functions called \ref lemon::DfsVisit::run() |
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| 1373 | /// "run()". |
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[100] | 1374 | /// \n |
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[244] | 1375 | /// If you need more control on the execution, first you must call |
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| 1376 | /// \ref lemon::DfsVisit::init() "init()", then you can add several |
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| 1377 | /// source nodes with \ref lemon::DfsVisit::addSource() "addSource()". |
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| 1378 | /// Finally \ref lemon::DfsVisit::start() "start()" will perform the |
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| 1379 | /// actual path computation. |
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[100] | 1380 | |
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| 1381 | /// @{ |
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[244] | 1382 | |
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[100] | 1383 | /// \brief Initializes the internal data structures. |
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| 1384 | /// |
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| 1385 | /// Initializes the internal data structures. |
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| 1386 | void init() { |
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| 1387 | create_maps(); |
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| 1388 | _stack.resize(countNodes(*_digraph)); |
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| 1389 | _stack_head = -1; |
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| 1390 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
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[209] | 1391 | _reached->set(u, false); |
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[100] | 1392 | } |
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| 1393 | } |
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[209] | 1394 | |
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[244] | 1395 | ///Adds a new source node. |
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| 1396 | |
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| 1397 | ///Adds a new source node to the set of nodes to be processed. |
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[100] | 1398 | /// |
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[244] | 1399 | ///\pre The stack must be empty. (Otherwise the algorithm gives |
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| 1400 | ///false results.) |
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| 1401 | /// |
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| 1402 | ///\warning Distances will be wrong (or at least strange) in case of |
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| 1403 | ///multiple sources. |
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| 1404 | void addSource(Node s) |
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| 1405 | { |
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| 1406 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
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[100] | 1407 | if(!(*_reached)[s]) { |
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[209] | 1408 | _reached->set(s,true); |
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| 1409 | _visitor->start(s); |
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| 1410 | _visitor->reach(s); |
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| 1411 | Arc e; |
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| 1412 | _digraph->firstOut(e, s); |
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| 1413 | if (e != INVALID) { |
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| 1414 | _stack[++_stack_head] = e; |
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| 1415 | } else { |
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| 1416 | _visitor->leave(s); |
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| 1417 | } |
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| 1418 | } |
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[100] | 1419 | } |
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[209] | 1420 | |
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[100] | 1421 | /// \brief Processes the next arc. |
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| 1422 | /// |
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| 1423 | /// Processes the next arc. |
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| 1424 | /// |
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| 1425 | /// \return The processed arc. |
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| 1426 | /// |
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[244] | 1427 | /// \pre The stack must not be empty. |
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[209] | 1428 | Arc processNextArc() { |
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[100] | 1429 | Arc e = _stack[_stack_head]; |
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| 1430 | Node m = _digraph->target(e); |
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| 1431 | if(!(*_reached)[m]) { |
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[209] | 1432 | _visitor->discover(e); |
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| 1433 | _visitor->reach(m); |
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| 1434 | _reached->set(m, true); |
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| 1435 | _digraph->firstOut(_stack[++_stack_head], m); |
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[100] | 1436 | } else { |
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[209] | 1437 | _visitor->examine(e); |
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| 1438 | m = _digraph->source(e); |
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| 1439 | _digraph->nextOut(_stack[_stack_head]); |
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[100] | 1440 | } |
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| 1441 | while (_stack_head>=0 && _stack[_stack_head] == INVALID) { |
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[209] | 1442 | _visitor->leave(m); |
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| 1443 | --_stack_head; |
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| 1444 | if (_stack_head >= 0) { |
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| 1445 | _visitor->backtrack(_stack[_stack_head]); |
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| 1446 | m = _digraph->source(_stack[_stack_head]); |
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| 1447 | _digraph->nextOut(_stack[_stack_head]); |
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| 1448 | } else { |
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| 1449 | _visitor->stop(m); |
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| 1450 | } |
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[100] | 1451 | } |
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| 1452 | return e; |
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| 1453 | } |
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| 1454 | |
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| 1455 | /// \brief Next arc to be processed. |
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| 1456 | /// |
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| 1457 | /// Next arc to be processed. |
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| 1458 | /// |
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| 1459 | /// \return The next arc to be processed or INVALID if the stack is |
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| 1460 | /// empty. |
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[244] | 1461 | Arc nextArc() const { |
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[100] | 1462 | return _stack_head >= 0 ? _stack[_stack_head] : INVALID; |
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| 1463 | } |
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| 1464 | |
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| 1465 | /// \brief Returns \c false if there are nodes |
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[244] | 1466 | /// to be processed. |
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[100] | 1467 | /// |
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| 1468 | /// Returns \c false if there are nodes |
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[244] | 1469 | /// to be processed in the queue (stack). |
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| 1470 | bool emptyQueue() const { return _stack_head < 0; } |
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[100] | 1471 | |
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| 1472 | /// \brief Returns the number of the nodes to be processed. |
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| 1473 | /// |
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[244] | 1474 | /// Returns the number of the nodes to be processed in the queue (stack). |
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| 1475 | int queueSize() const { return _stack_head + 1; } |
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[209] | 1476 | |
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[100] | 1477 | /// \brief Executes the algorithm. |
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| 1478 | /// |
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| 1479 | /// Executes the algorithm. |
---|
| 1480 | /// |
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[244] | 1481 | /// This method runs the %DFS algorithm from the root node |
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| 1482 | /// in order to compute the %DFS path to each node. |
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| 1483 | /// |
---|
| 1484 | /// The algorithm computes |
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| 1485 | /// - the %DFS tree, |
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| 1486 | /// - the distance of each node from the root in the %DFS tree. |
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| 1487 | /// |
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| 1488 | /// \pre init() must be called and a root node should be |
---|
| 1489 | /// added with addSource() before using this function. |
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| 1490 | /// |
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| 1491 | /// \note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
| 1492 | /// \code |
---|
| 1493 | /// while ( !d.emptyQueue() ) { |
---|
| 1494 | /// d.processNextArc(); |
---|
| 1495 | /// } |
---|
| 1496 | /// \endcode |
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[100] | 1497 | void start() { |
---|
| 1498 | while ( !emptyQueue() ) processNextArc(); |
---|
| 1499 | } |
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[209] | 1500 | |
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[244] | 1501 | /// \brief Executes the algorithm until the given target node is reached. |
---|
[100] | 1502 | /// |
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[244] | 1503 | /// Executes the algorithm until the given target node is reached. |
---|
[100] | 1504 | /// |
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[244] | 1505 | /// This method runs the %DFS algorithm from the root node |
---|
[286] | 1506 | /// in order to compute the DFS path to \c t. |
---|
[244] | 1507 | /// |
---|
| 1508 | /// The algorithm computes |
---|
[286] | 1509 | /// - the %DFS path to \c t, |
---|
| 1510 | /// - the distance of \c t from the root in the %DFS tree. |
---|
[244] | 1511 | /// |
---|
| 1512 | /// \pre init() must be called and a root node should be added |
---|
[100] | 1513 | /// with addSource() before using this function. |
---|
[286] | 1514 | void start(Node t) { |
---|
| 1515 | while ( !emptyQueue() && _digraph->target(_stack[_stack_head]) != t ) |
---|
[209] | 1516 | processNextArc(); |
---|
[100] | 1517 | } |
---|
[209] | 1518 | |
---|
[100] | 1519 | /// \brief Executes the algorithm until a condition is met. |
---|
| 1520 | /// |
---|
| 1521 | /// Executes the algorithm until a condition is met. |
---|
| 1522 | /// |
---|
[244] | 1523 | /// This method runs the %DFS algorithm from the root node |
---|
| 1524 | /// until an arc \c a with <tt>am[a]</tt> true is found. |
---|
| 1525 | /// |
---|
| 1526 | /// \param am A \c bool (or convertible) arc map. The algorithm |
---|
| 1527 | /// will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
---|
| 1528 | /// |
---|
| 1529 | /// \return The reached arc \c a with <tt>am[a]</tt> true or |
---|
| 1530 | /// \c INVALID if no such arc was found. |
---|
| 1531 | /// |
---|
| 1532 | /// \pre init() must be called and a root node should be added |
---|
[100] | 1533 | /// with addSource() before using this function. |
---|
| 1534 | /// |
---|
[244] | 1535 | /// \warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
---|
[100] | 1536 | /// not a node map. |
---|
[244] | 1537 | template <typename AM> |
---|
| 1538 | Arc start(const AM &am) { |
---|
| 1539 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
---|
[100] | 1540 | processNextArc(); |
---|
| 1541 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
| 1542 | } |
---|
| 1543 | |
---|
[286] | 1544 | /// \brief Runs the algorithm from the given source node. |
---|
[100] | 1545 | /// |
---|
[244] | 1546 | /// This method runs the %DFS algorithm from node \c s. |
---|
| 1547 | /// in order to compute the DFS path to each node. |
---|
| 1548 | /// |
---|
| 1549 | /// The algorithm computes |
---|
| 1550 | /// - the %DFS tree, |
---|
| 1551 | /// - the distance of each node from the root in the %DFS tree. |
---|
| 1552 | /// |
---|
| 1553 | /// \note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1554 | ///\code |
---|
| 1555 | /// d.init(); |
---|
| 1556 | /// d.addSource(s); |
---|
| 1557 | /// d.start(); |
---|
| 1558 | ///\endcode |
---|
| 1559 | void run(Node s) { |
---|
| 1560 | init(); |
---|
| 1561 | addSource(s); |
---|
| 1562 | start(); |
---|
| 1563 | } |
---|
| 1564 | |
---|
[244] | 1565 | /// \brief Finds the %DFS path between \c s and \c t. |
---|
| 1566 | |
---|
| 1567 | /// This method runs the %DFS algorithm from node \c s |
---|
[286] | 1568 | /// in order to compute the DFS path to node \c t |
---|
| 1569 | /// (it stops searching when \c t is processed). |
---|
[244] | 1570 | /// |
---|
[286] | 1571 | /// \return \c true if \c t is reachable form \c s. |
---|
[244] | 1572 | /// |
---|
| 1573 | /// \note Apart from the return value, <tt>d.run(s,t)</tt> is |
---|
| 1574 | /// just a shortcut of the following code. |
---|
| 1575 | ///\code |
---|
| 1576 | /// d.init(); |
---|
| 1577 | /// d.addSource(s); |
---|
| 1578 | /// d.start(t); |
---|
| 1579 | ///\endcode |
---|
[286] | 1580 | bool run(Node s,Node t) { |
---|
[244] | 1581 | init(); |
---|
| 1582 | addSource(s); |
---|
| 1583 | start(t); |
---|
[286] | 1584 | return reached(t); |
---|
[244] | 1585 | } |
---|
| 1586 | |
---|
| 1587 | /// \brief Runs the algorithm to visit all nodes in the digraph. |
---|
[209] | 1588 | |
---|
[100] | 1589 | /// This method runs the %DFS algorithm in order to |
---|
[244] | 1590 | /// compute the %DFS path to each node. |
---|
[100] | 1591 | /// |
---|
[244] | 1592 | /// The algorithm computes |
---|
| 1593 | /// - the %DFS tree, |
---|
| 1594 | /// - the distance of each node from the root in the %DFS tree. |
---|
| 1595 | /// |
---|
| 1596 | /// \note <tt>d.run()</tt> is just a shortcut of the following code. |
---|
[100] | 1597 | ///\code |
---|
[244] | 1598 | /// d.init(); |
---|
| 1599 | /// for (NodeIt n(digraph); n != INVALID; ++n) { |
---|
| 1600 | /// if (!d.reached(n)) { |
---|
| 1601 | /// d.addSource(n); |
---|
| 1602 | /// d.start(); |
---|
| 1603 | /// } |
---|
| 1604 | /// } |
---|
[100] | 1605 | ///\endcode |
---|
| 1606 | void run() { |
---|
| 1607 | init(); |
---|
| 1608 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
| 1609 | if (!reached(it)) { |
---|
| 1610 | addSource(it); |
---|
| 1611 | start(); |
---|
| 1612 | } |
---|
| 1613 | } |
---|
| 1614 | } |
---|
[244] | 1615 | |
---|
[100] | 1616 | ///@} |
---|
| 1617 | |
---|
| 1618 | /// \name Query Functions |
---|
| 1619 | /// The result of the %DFS algorithm can be obtained using these |
---|
| 1620 | /// functions.\n |
---|
[244] | 1621 | /// Either \ref lemon::DfsVisit::run() "run()" or |
---|
| 1622 | /// \ref lemon::DfsVisit::start() "start()" must be called before |
---|
| 1623 | /// using them. |
---|
[100] | 1624 | ///@{ |
---|
[244] | 1625 | |
---|
| 1626 | /// \brief Checks if a node is reachable from the root(s). |
---|
[100] | 1627 | /// |
---|
| 1628 | /// Returns \c true if \c v is reachable from the root(s). |
---|
| 1629 | /// \pre Either \ref run() or \ref start() |
---|
| 1630 | /// must be called before using this function. |
---|
| 1631 | bool reached(Node v) { return (*_reached)[v]; } |
---|
[244] | 1632 | |
---|
[100] | 1633 | ///@} |
---|
[244] | 1634 | |
---|
[100] | 1635 | }; |
---|
| 1636 | |
---|
| 1637 | } //END OF NAMESPACE LEMON |
---|
| 1638 | |
---|
| 1639 | #endif |
---|