[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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[463] | 5 | * Copyright (C) 2003-2009 |
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[100] | 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | #ifndef LEMON_DFS_H |
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| 20 | #define LEMON_DFS_H |
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| 21 | |
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| 22 | ///\ingroup search |
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| 23 | ///\file |
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[244] | 24 | ///\brief DFS algorithm. |
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[100] | 25 | |
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| 26 | #include <lemon/list_graph.h> |
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| 27 | #include <lemon/bits/path_dump.h> |
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[220] | 28 | #include <lemon/core.h> |
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[100] | 29 | #include <lemon/error.h> |
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| 30 | #include <lemon/maps.h> |
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[278] | 31 | #include <lemon/path.h> |
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[100] | 32 | |
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| 33 | namespace lemon { |
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| 34 | |
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| 35 | ///Default traits class of Dfs class. |
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| 36 | |
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| 37 | ///Default traits class of Dfs class. |
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[157] | 38 | ///\tparam GR Digraph type. |
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[100] | 39 | template<class GR> |
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| 40 | struct DfsDefaultTraits |
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| 41 | { |
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[244] | 42 | ///The type of the digraph the algorithm runs on. |
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[100] | 43 | typedef GR Digraph; |
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[244] | 44 | |
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| 45 | ///\brief The type of the map that stores the predecessor |
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[100] | 46 | ///arcs of the %DFS paths. |
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[209] | 47 | /// |
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[244] | 48 | ///The type of the map that stores the predecessor |
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[100] | 49 | ///arcs of the %DFS paths. |
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[763] | 50 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[244] | 51 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
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[525] | 52 | ///Instantiates a \c PredMap. |
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[209] | 53 | |
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[525] | 54 | ///This function instantiates a \ref PredMap. |
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[244] | 55 | ///\param g is the digraph, to which we would like to define the |
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[525] | 56 | ///\ref PredMap. |
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[244] | 57 | static PredMap *createPredMap(const Digraph &g) |
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[100] | 58 | { |
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[244] | 59 | return new PredMap(g); |
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[100] | 60 | } |
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| 61 | |
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| 62 | ///The type of the map that indicates which nodes are processed. |
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[209] | 63 | |
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[100] | 64 | ///The type of the map that indicates which nodes are processed. |
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[763] | 65 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[833] | 66 | ///By default, it is a NullMap. |
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[100] | 67 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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[525] | 68 | ///Instantiates a \c ProcessedMap. |
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[209] | 69 | |
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[525] | 70 | ///This function instantiates a \ref ProcessedMap. |
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[100] | 71 | ///\param g is the digraph, to which |
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[525] | 72 | ///we would like to define the \ref ProcessedMap. |
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[100] | 73 | #ifdef DOXYGEN |
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[244] | 74 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 75 | #else |
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[244] | 76 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 77 | #endif |
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| 78 | { |
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| 79 | return new ProcessedMap(); |
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| 80 | } |
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[244] | 81 | |
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[100] | 82 | ///The type of the map that indicates which nodes are reached. |
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[209] | 83 | |
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[100] | 84 | ///The type of the map that indicates which nodes are reached. |
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[763] | 85 | ///It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 86 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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[525] | 87 | ///Instantiates a \c ReachedMap. |
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[209] | 88 | |
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[525] | 89 | ///This function instantiates a \ref ReachedMap. |
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[244] | 90 | ///\param g is the digraph, to which |
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[525] | 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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[763] | 100 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 101 | typedef typename Digraph::template NodeMap<int> DistMap; |
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[525] | 102 | ///Instantiates a \c DistMap. |
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[209] | 103 | |
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[525] | 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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[525] | 106 | ///\ref DistMap. |
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[244] | 107 | static DistMap *createDistMap(const Digraph &g) |
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[100] | 108 | { |
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[244] | 109 | return new DistMap(g); |
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[100] | 110 | } |
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| 111 | }; |
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[209] | 112 | |
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[100] | 113 | ///%DFS algorithm class. |
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[209] | 114 | |
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[100] | 115 | ///\ingroup search |
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| 116 | ///This class provides an efficient implementation of the %DFS algorithm. |
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| 117 | /// |
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[278] | 118 | ///There is also a \ref dfs() "function-type interface" for the DFS |
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[244] | 119 | ///algorithm, which is convenient in the simplier cases and it can be |
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| 120 | ///used easier. |
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| 121 | /// |
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| 122 | ///\tparam GR The type of the digraph the algorithm runs on. |
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[421] | 123 | ///The default type is \ref ListDigraph. |
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[891] | 124 | ///\tparam TR The traits class that defines various types used by the |
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| 125 | ///algorithm. By default, it is \ref DfsDefaultTraits |
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| 126 | ///"DfsDefaultTraits<GR>". |
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| 127 | ///In most cases, this parameter should not be set directly, |
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| 128 | ///consider to use the named template parameters instead. |
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[100] | 129 | #ifdef DOXYGEN |
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| 130 | template <typename GR, |
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[209] | 131 | typename TR> |
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[100] | 132 | #else |
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| 133 | template <typename GR=ListDigraph, |
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[209] | 134 | typename TR=DfsDefaultTraits<GR> > |
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[100] | 135 | #endif |
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| 136 | class Dfs { |
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| 137 | public: |
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| 138 | |
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[244] | 139 | ///The type of the digraph the algorithm runs on. |
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| 140 | typedef typename TR::Digraph Digraph; |
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| 141 | |
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| 142 | ///\brief The type of the map that stores the predecessor arcs of the |
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| 143 | ///DFS paths. |
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| 144 | typedef typename TR::PredMap PredMap; |
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| 145 | ///The type of the map that stores the distances of the nodes. |
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| 146 | typedef typename TR::DistMap DistMap; |
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| 147 | ///The type of the map that indicates which nodes are reached. |
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| 148 | typedef typename TR::ReachedMap ReachedMap; |
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| 149 | ///The type of the map that indicates which nodes are processed. |
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| 150 | typedef typename TR::ProcessedMap ProcessedMap; |
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| 151 | ///The type of the paths. |
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| 152 | typedef PredMapPath<Digraph, PredMap> Path; |
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| 153 | |
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[421] | 154 | ///The \ref DfsDefaultTraits "traits class" of the algorithm. |
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[100] | 155 | typedef TR Traits; |
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[244] | 156 | |
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| 157 | private: |
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| 158 | |
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[100] | 159 | typedef typename Digraph::Node Node; |
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| 160 | typedef typename Digraph::NodeIt NodeIt; |
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| 161 | typedef typename Digraph::Arc Arc; |
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| 162 | typedef typename Digraph::OutArcIt OutArcIt; |
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[209] | 163 | |
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[244] | 164 | //Pointer to the underlying digraph. |
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[100] | 165 | const Digraph *G; |
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[244] | 166 | //Pointer to the map of predecessor arcs. |
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[100] | 167 | PredMap *_pred; |
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[244] | 168 | //Indicates if _pred is locally allocated (true) or not. |
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[100] | 169 | bool local_pred; |
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[244] | 170 | //Pointer to the map of distances. |
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[100] | 171 | DistMap *_dist; |
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[244] | 172 | //Indicates if _dist is locally allocated (true) or not. |
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[100] | 173 | bool local_dist; |
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[244] | 174 | //Pointer to the map of reached status of the nodes. |
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[100] | 175 | ReachedMap *_reached; |
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[244] | 176 | //Indicates if _reached is locally allocated (true) or not. |
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[100] | 177 | bool local_reached; |
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[244] | 178 | //Pointer to the map of processed status of the nodes. |
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[100] | 179 | ProcessedMap *_processed; |
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[244] | 180 | //Indicates if _processed is locally allocated (true) or not. |
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[100] | 181 | bool local_processed; |
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| 182 | |
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| 183 | std::vector<typename Digraph::OutArcIt> _stack; |
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| 184 | int _stack_head; |
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| 185 | |
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[280] | 186 | //Creates the maps if necessary. |
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[209] | 187 | void create_maps() |
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[100] | 188 | { |
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| 189 | if(!_pred) { |
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[209] | 190 | local_pred = true; |
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| 191 | _pred = Traits::createPredMap(*G); |
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[100] | 192 | } |
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| 193 | if(!_dist) { |
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[209] | 194 | local_dist = true; |
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| 195 | _dist = Traits::createDistMap(*G); |
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[100] | 196 | } |
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| 197 | if(!_reached) { |
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[209] | 198 | local_reached = true; |
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| 199 | _reached = Traits::createReachedMap(*G); |
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[100] | 200 | } |
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| 201 | if(!_processed) { |
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[209] | 202 | local_processed = true; |
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| 203 | _processed = Traits::createProcessedMap(*G); |
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[100] | 204 | } |
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| 205 | } |
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| 206 | |
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| 207 | protected: |
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| 208 | |
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| 209 | Dfs() {} |
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[209] | 210 | |
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[100] | 211 | public: |
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| 212 | |
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| 213 | typedef Dfs Create; |
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| 214 | |
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[631] | 215 | ///\name Named Template Parameters |
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[100] | 216 | |
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| 217 | ///@{ |
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| 218 | |
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| 219 | template <class T> |
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[257] | 220 | struct SetPredMapTraits : public Traits { |
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[100] | 221 | typedef T PredMap; |
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[244] | 222 | static PredMap *createPredMap(const Digraph &) |
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[100] | 223 | { |
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[290] | 224 | LEMON_ASSERT(false, "PredMap is not initialized"); |
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| 225 | return 0; // ignore warnings |
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[100] | 226 | } |
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| 227 | }; |
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| 228 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[525] | 229 | ///\c PredMap type. |
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[100] | 230 | /// |
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[244] | 231 | ///\ref named-templ-param "Named parameter" for setting |
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[525] | 232 | ///\c PredMap type. |
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[763] | 233 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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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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[525] | 249 | ///\c 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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[525] | 252 | ///\c DistMap type. |
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[763] | 253 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 254 | template <class T> |
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[257] | 255 | struct SetDistMap : public Dfs< Digraph, SetDistMapTraits<T> > { |
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| 256 | typedef Dfs<Digraph, SetDistMapTraits<T> > Create; |
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[100] | 257 | }; |
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[209] | 258 | |
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[100] | 259 | template <class T> |
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[257] | 260 | struct SetReachedMapTraits : public Traits { |
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[100] | 261 | typedef T ReachedMap; |
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[209] | 262 | static ReachedMap *createReachedMap(const Digraph &) |
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[100] | 263 | { |
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[290] | 264 | LEMON_ASSERT(false, "ReachedMap is not initialized"); |
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| 265 | return 0; // ignore warnings |
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[100] | 266 | } |
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| 267 | }; |
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| 268 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[525] | 269 | ///\c ReachedMap type. |
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[100] | 270 | /// |
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[244] | 271 | ///\ref named-templ-param "Named parameter" for setting |
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[525] | 272 | ///\c ReachedMap type. |
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[763] | 273 | ///It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 274 | template <class T> |
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[257] | 275 | struct SetReachedMap : public Dfs< Digraph, SetReachedMapTraits<T> > { |
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| 276 | typedef Dfs< Digraph, SetReachedMapTraits<T> > Create; |
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[100] | 277 | }; |
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| 278 | |
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| 279 | template <class T> |
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[257] | 280 | struct SetProcessedMapTraits : public Traits { |
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[100] | 281 | typedef T ProcessedMap; |
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[209] | 282 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 283 | { |
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[290] | 284 | LEMON_ASSERT(false, "ProcessedMap is not initialized"); |
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| 285 | return 0; // ignore warnings |
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[100] | 286 | } |
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| 287 | }; |
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| 288 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[525] | 289 | ///\c ProcessedMap type. |
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[100] | 290 | /// |
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[244] | 291 | ///\ref named-templ-param "Named parameter" for setting |
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[525] | 292 | ///\c ProcessedMap type. |
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[763] | 293 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 294 | template <class T> |
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[257] | 295 | struct SetProcessedMap : public Dfs< Digraph, SetProcessedMapTraits<T> > { |
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| 296 | typedef Dfs< Digraph, SetProcessedMapTraits<T> > Create; |
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[100] | 297 | }; |
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[209] | 298 | |
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[257] | 299 | struct SetStandardProcessedMapTraits : public Traits { |
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[100] | 300 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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[244] | 301 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 302 | { |
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[244] | 303 | return new ProcessedMap(g); |
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[100] | 304 | } |
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| 305 | }; |
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[244] | 306 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[525] | 307 | ///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 308 | /// |
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[244] | 309 | ///\ref named-templ-param "Named parameter" for setting |
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[525] | 310 | ///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[244] | 311 | ///If you don't set it explicitly, it will be automatically allocated. |
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[257] | 312 | struct SetStandardProcessedMap : |
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| 313 | public Dfs< Digraph, SetStandardProcessedMapTraits > { |
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| 314 | typedef Dfs< Digraph, SetStandardProcessedMapTraits > Create; |
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[100] | 315 | }; |
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[209] | 316 | |
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[100] | 317 | ///@} |
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| 318 | |
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[209] | 319 | public: |
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| 320 | |
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[100] | 321 | ///Constructor. |
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[209] | 322 | |
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[244] | 323 | ///Constructor. |
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| 324 | ///\param g The digraph the algorithm runs on. |
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| 325 | Dfs(const Digraph &g) : |
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| 326 | G(&g), |
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[100] | 327 | _pred(NULL), local_pred(false), |
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| 328 | _dist(NULL), local_dist(false), |
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| 329 | _reached(NULL), local_reached(false), |
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| 330 | _processed(NULL), local_processed(false) |
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| 331 | { } |
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[209] | 332 | |
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[100] | 333 | ///Destructor. |
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[209] | 334 | ~Dfs() |
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[100] | 335 | { |
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| 336 | if(local_pred) delete _pred; |
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| 337 | if(local_dist) delete _dist; |
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| 338 | if(local_reached) delete _reached; |
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| 339 | if(local_processed) delete _processed; |
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| 340 | } |
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| 341 | |
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[244] | 342 | ///Sets the map that stores the predecessor arcs. |
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[100] | 343 | |
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[244] | 344 | ///Sets the map that stores the predecessor arcs. |
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[421] | 345 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 346 | ///or \ref init(), an instance will be allocated automatically. |
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| 347 | ///The destructor deallocates this automatically allocated map, |
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| 348 | ///of course. |
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[100] | 349 | ///\return <tt> (*this) </tt> |
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[209] | 350 | Dfs &predMap(PredMap &m) |
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[100] | 351 | { |
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| 352 | if(local_pred) { |
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[209] | 353 | delete _pred; |
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| 354 | local_pred=false; |
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[100] | 355 | } |
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| 356 | _pred = &m; |
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| 357 | return *this; |
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| 358 | } |
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| 359 | |
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[244] | 360 | ///Sets the map that indicates which nodes are reached. |
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[100] | 361 | |
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[244] | 362 | ///Sets the map that indicates which nodes are reached. |
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[421] | 363 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 364 | ///or \ref init(), an instance will be allocated automatically. |
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| 365 | ///The destructor deallocates this automatically allocated map, |
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| 366 | ///of course. |
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[244] | 367 | ///\return <tt> (*this) </tt> |
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| 368 | Dfs &reachedMap(ReachedMap &m) |
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| 369 | { |
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| 370 | if(local_reached) { |
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| 371 | delete _reached; |
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| 372 | local_reached=false; |
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| 373 | } |
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| 374 | _reached = &m; |
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| 375 | return *this; |
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| 376 | } |
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| 377 | |
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| 378 | ///Sets the map that indicates which nodes are processed. |
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| 379 | |
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| 380 | ///Sets the map that indicates which nodes are processed. |
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[421] | 381 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 382 | ///or \ref init(), an instance will be allocated automatically. |
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| 383 | ///The destructor deallocates this automatically allocated map, |
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| 384 | ///of course. |
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[244] | 385 | ///\return <tt> (*this) </tt> |
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| 386 | Dfs &processedMap(ProcessedMap &m) |
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| 387 | { |
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| 388 | if(local_processed) { |
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| 389 | delete _processed; |
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| 390 | local_processed=false; |
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| 391 | } |
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| 392 | _processed = &m; |
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| 393 | return *this; |
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| 394 | } |
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| 395 | |
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| 396 | ///Sets the map that stores the distances of the nodes. |
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| 397 | |
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| 398 | ///Sets the map that stores the distances of the nodes calculated by |
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| 399 | ///the algorithm. |
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[421] | 400 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 401 | ///or \ref init(), an instance will be allocated automatically. |
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| 402 | ///The destructor deallocates this automatically allocated map, |
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| 403 | ///of course. |
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[100] | 404 | ///\return <tt> (*this) </tt> |
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[209] | 405 | Dfs &distMap(DistMap &m) |
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[100] | 406 | { |
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| 407 | if(local_dist) { |
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[209] | 408 | delete _dist; |
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| 409 | local_dist=false; |
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[100] | 410 | } |
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| 411 | _dist = &m; |
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| 412 | return *this; |
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| 413 | } |
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| 414 | |
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[244] | 415 | public: |
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[100] | 416 | |
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[421] | 417 | ///\name Execution Control |
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| 418 | ///The simplest way to execute the DFS algorithm is to use one of the |
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| 419 | ///member functions called \ref run(Node) "run()".\n |
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[760] | 420 | ///If you need better control on the execution, you have to call |
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| 421 | ///\ref init() first, then you can add a source node with \ref addSource() |
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[421] | 422 | ///and perform the actual computation with \ref start(). |
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| 423 | ///This procedure can be repeated if there are nodes that have not |
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| 424 | ///been reached. |
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[100] | 425 | |
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| 426 | ///@{ |
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| 427 | |
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[421] | 428 | ///\brief Initializes the internal data structures. |
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| 429 | /// |
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[100] | 430 | ///Initializes the internal data structures. |
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| 431 | void init() |
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| 432 | { |
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| 433 | create_maps(); |
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| 434 | _stack.resize(countNodes(*G)); |
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| 435 | _stack_head=-1; |
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| 436 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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[209] | 437 | _pred->set(u,INVALID); |
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| 438 | _reached->set(u,false); |
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| 439 | _processed->set(u,false); |
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[100] | 440 | } |
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| 441 | } |
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[209] | 442 | |
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[100] | 443 | ///Adds a new source node. |
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| 444 | |
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| 445 | ///Adds a new source node to the set of nodes to be processed. |
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| 446 | /// |
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[421] | 447 | ///\pre The stack must be empty. Otherwise the algorithm gives |
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| 448 | ///wrong results. (One of the outgoing arcs of all the source nodes |
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| 449 | ///except for the last one will not be visited and distances will |
---|
| 450 | ///also be wrong.) |
---|
[100] | 451 | void addSource(Node s) |
---|
| 452 | { |
---|
[244] | 453 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
---|
[100] | 454 | if(!(*_reached)[s]) |
---|
[209] | 455 | { |
---|
| 456 | _reached->set(s,true); |
---|
| 457 | _pred->set(s,INVALID); |
---|
| 458 | OutArcIt e(*G,s); |
---|
| 459 | if(e!=INVALID) { |
---|
| 460 | _stack[++_stack_head]=e; |
---|
| 461 | _dist->set(s,_stack_head); |
---|
| 462 | } |
---|
| 463 | else { |
---|
| 464 | _processed->set(s,true); |
---|
| 465 | _dist->set(s,0); |
---|
| 466 | } |
---|
| 467 | } |
---|
[100] | 468 | } |
---|
[209] | 469 | |
---|
[100] | 470 | ///Processes the next arc. |
---|
| 471 | |
---|
| 472 | ///Processes the next arc. |
---|
| 473 | /// |
---|
| 474 | ///\return The processed arc. |
---|
| 475 | /// |
---|
[244] | 476 | ///\pre The stack must not be empty. |
---|
[100] | 477 | Arc processNextArc() |
---|
[209] | 478 | { |
---|
[100] | 479 | Node m; |
---|
| 480 | Arc e=_stack[_stack_head]; |
---|
| 481 | if(!(*_reached)[m=G->target(e)]) { |
---|
[209] | 482 | _pred->set(m,e); |
---|
| 483 | _reached->set(m,true); |
---|
| 484 | ++_stack_head; |
---|
| 485 | _stack[_stack_head] = OutArcIt(*G, m); |
---|
| 486 | _dist->set(m,_stack_head); |
---|
[100] | 487 | } |
---|
| 488 | else { |
---|
[209] | 489 | m=G->source(e); |
---|
| 490 | ++_stack[_stack_head]; |
---|
[100] | 491 | } |
---|
| 492 | while(_stack_head>=0 && _stack[_stack_head]==INVALID) { |
---|
[209] | 493 | _processed->set(m,true); |
---|
| 494 | --_stack_head; |
---|
| 495 | if(_stack_head>=0) { |
---|
| 496 | m=G->source(_stack[_stack_head]); |
---|
| 497 | ++_stack[_stack_head]; |
---|
| 498 | } |
---|
[100] | 499 | } |
---|
| 500 | return e; |
---|
| 501 | } |
---|
[244] | 502 | |
---|
[100] | 503 | ///Next arc to be processed. |
---|
| 504 | |
---|
| 505 | ///Next arc to be processed. |
---|
| 506 | /// |
---|
[244] | 507 | ///\return The next arc to be processed or \c INVALID if the stack |
---|
| 508 | ///is empty. |
---|
| 509 | OutArcIt nextArc() const |
---|
[209] | 510 | { |
---|
[100] | 511 | return _stack_head>=0?_stack[_stack_head]:INVALID; |
---|
| 512 | } |
---|
| 513 | |
---|
[421] | 514 | ///Returns \c false if there are nodes to be processed. |
---|
| 515 | |
---|
| 516 | ///Returns \c false if there are nodes to be processed |
---|
| 517 | ///in the queue (stack). |
---|
[244] | 518 | bool emptyQueue() const { return _stack_head<0; } |
---|
| 519 | |
---|
[100] | 520 | ///Returns the number of the nodes to be processed. |
---|
[209] | 521 | |
---|
[421] | 522 | ///Returns the number of the nodes to be processed |
---|
| 523 | ///in the queue (stack). |
---|
[244] | 524 | int queueSize() const { return _stack_head+1; } |
---|
[209] | 525 | |
---|
[100] | 526 | ///Executes the algorithm. |
---|
| 527 | |
---|
| 528 | ///Executes the algorithm. |
---|
| 529 | /// |
---|
[244] | 530 | ///This method runs the %DFS algorithm from the root node |
---|
| 531 | ///in order to compute the DFS path to each node. |
---|
[100] | 532 | /// |
---|
[244] | 533 | /// The algorithm computes |
---|
| 534 | ///- the %DFS tree, |
---|
| 535 | ///- the distance of each node from the root in the %DFS tree. |
---|
[100] | 536 | /// |
---|
[244] | 537 | ///\pre init() must be called and a root node should be |
---|
| 538 | ///added with addSource() before using this function. |
---|
| 539 | /// |
---|
| 540 | ///\note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
| 541 | ///\code |
---|
| 542 | /// while ( !d.emptyQueue() ) { |
---|
| 543 | /// d.processNextArc(); |
---|
| 544 | /// } |
---|
| 545 | ///\endcode |
---|
[100] | 546 | void start() |
---|
| 547 | { |
---|
| 548 | while ( !emptyQueue() ) processNextArc(); |
---|
| 549 | } |
---|
[209] | 550 | |
---|
[244] | 551 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 552 | |
---|
[244] | 553 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 554 | /// |
---|
[244] | 555 | ///This method runs the %DFS algorithm from the root node |
---|
[286] | 556 | ///in order to compute the DFS path to \c t. |
---|
[100] | 557 | /// |
---|
[244] | 558 | ///The algorithm computes |
---|
[286] | 559 | ///- the %DFS path to \c t, |
---|
| 560 | ///- the distance of \c t from the root in the %DFS tree. |
---|
[100] | 561 | /// |
---|
[244] | 562 | ///\pre init() must be called and a root node should be |
---|
| 563 | ///added with addSource() before using this function. |
---|
[286] | 564 | void start(Node t) |
---|
[100] | 565 | { |
---|
[286] | 566 | while ( !emptyQueue() && G->target(_stack[_stack_head])!=t ) |
---|
[209] | 567 | processNextArc(); |
---|
[100] | 568 | } |
---|
[209] | 569 | |
---|
[100] | 570 | ///Executes the algorithm until a condition is met. |
---|
| 571 | |
---|
| 572 | ///Executes the algorithm until a condition is met. |
---|
| 573 | /// |
---|
[244] | 574 | ///This method runs the %DFS algorithm from the root node |
---|
| 575 | ///until an arc \c a with <tt>am[a]</tt> true is found. |
---|
[100] | 576 | /// |
---|
[244] | 577 | ///\param am A \c bool (or convertible) arc map. The algorithm |
---|
| 578 | ///will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
---|
[100] | 579 | /// |
---|
[244] | 580 | ///\return The reached arc \c a with <tt>am[a]</tt> true or |
---|
[100] | 581 | ///\c INVALID if no such arc was found. |
---|
| 582 | /// |
---|
[244] | 583 | ///\pre init() must be called and a root node should be |
---|
| 584 | ///added with addSource() before using this function. |
---|
| 585 | /// |
---|
| 586 | ///\warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
---|
[100] | 587 | ///not a node map. |
---|
[244] | 588 | template<class ArcBoolMap> |
---|
| 589 | Arc start(const ArcBoolMap &am) |
---|
[100] | 590 | { |
---|
[244] | 591 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
---|
[100] | 592 | processNextArc(); |
---|
| 593 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
| 594 | } |
---|
| 595 | |
---|
[286] | 596 | ///Runs the algorithm from the given source node. |
---|
[209] | 597 | |
---|
[244] | 598 | ///This method runs the %DFS algorithm from node \c s |
---|
| 599 | ///in order to compute the DFS path to each node. |
---|
[100] | 600 | /// |
---|
[244] | 601 | ///The algorithm computes |
---|
| 602 | ///- the %DFS tree, |
---|
| 603 | ///- the distance of each node from the root in the %DFS tree. |
---|
| 604 | /// |
---|
| 605 | ///\note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 606 | ///\code |
---|
| 607 | /// d.init(); |
---|
[244] | 608 | /// d.addSource(s); |
---|
| 609 | /// d.start(); |
---|
| 610 | ///\endcode |
---|
| 611 | void run(Node s) { |
---|
| 612 | init(); |
---|
| 613 | addSource(s); |
---|
| 614 | start(); |
---|
| 615 | } |
---|
| 616 | |
---|
| 617 | ///Finds the %DFS path between \c s and \c t. |
---|
| 618 | |
---|
| 619 | ///This method runs the %DFS algorithm from node \c s |
---|
[286] | 620 | ///in order to compute the DFS path to node \c t |
---|
| 621 | ///(it stops searching when \c t is processed) |
---|
[244] | 622 | /// |
---|
[286] | 623 | ///\return \c true if \c t is reachable form \c s. |
---|
[244] | 624 | /// |
---|
| 625 | ///\note Apart from the return value, <tt>d.run(s,t)</tt> is |
---|
| 626 | ///just a shortcut of the following code. |
---|
| 627 | ///\code |
---|
| 628 | /// d.init(); |
---|
| 629 | /// d.addSource(s); |
---|
| 630 | /// d.start(t); |
---|
| 631 | ///\endcode |
---|
[286] | 632 | bool run(Node s,Node t) { |
---|
[244] | 633 | init(); |
---|
| 634 | addSource(s); |
---|
| 635 | start(t); |
---|
[286] | 636 | return reached(t); |
---|
[244] | 637 | } |
---|
| 638 | |
---|
| 639 | ///Runs the algorithm to visit all nodes in the digraph. |
---|
| 640 | |
---|
[834] | 641 | ///This method runs the %DFS algorithm in order to visit all nodes |
---|
| 642 | ///in the digraph. |
---|
[244] | 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 |
---|
[421] | 667 | ///The results of the DFS algorithm can be obtained using these |
---|
[100] | 668 | ///functions.\n |
---|
[421] | 669 | ///Either \ref run(Node) "run()" or \ref start() should be called |
---|
| 670 | ///before using them. |
---|
[209] | 671 | |
---|
[100] | 672 | ///@{ |
---|
| 673 | |
---|
[763] | 674 | ///The DFS path to the given node. |
---|
[100] | 675 | |
---|
[763] | 676 | ///Returns the DFS path to the given node from the root(s). |
---|
[244] | 677 | /// |
---|
[421] | 678 | ///\warning \c t should be reached from the root(s). |
---|
[244] | 679 | /// |
---|
[421] | 680 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 681 | ///must be called before using this function. |
---|
[244] | 682 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
[209] | 683 | |
---|
[763] | 684 | ///The distance of the given node from the root(s). |
---|
[100] | 685 | |
---|
[763] | 686 | ///Returns the distance of the given node from the root(s). |
---|
[244] | 687 | /// |
---|
[421] | 688 | ///\warning If node \c v is not reached from the root(s), then |
---|
[244] | 689 | ///the return value of this function is undefined. |
---|
| 690 | /// |
---|
[421] | 691 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 692 | ///must be called before using this function. |
---|
[100] | 693 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 694 | |
---|
[763] | 695 | ///Returns the 'previous arc' of the %DFS tree for the given node. |
---|
[100] | 696 | |
---|
[244] | 697 | ///This function returns the 'previous arc' of the %DFS tree for the |
---|
[421] | 698 | ///node \c v, i.e. it returns the last arc of a %DFS path from a |
---|
| 699 | ///root to \c v. It is \c INVALID if \c v is not reached from the |
---|
| 700 | ///root(s) or if \c v is a root. |
---|
[244] | 701 | /// |
---|
| 702 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
[763] | 703 | ///\ref predNode() and \ref predMap(). |
---|
[244] | 704 | /// |
---|
[421] | 705 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 706 | ///must be called before using this function. |
---|
[100] | 707 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 708 | |
---|
[763] | 709 | ///Returns the 'previous node' of the %DFS tree for the given node. |
---|
[100] | 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 |
---|
[763] | 713 | ///of a %DFS path from a root to \c v. It is \c INVALID |
---|
[421] | 714 | ///if \c v is not reached from the root(s) or if \c v is a root. |
---|
[244] | 715 | /// |
---|
| 716 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
[763] | 717 | ///\ref predArc() and \ref predMap(). |
---|
[244] | 718 | /// |
---|
[421] | 719 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 720 | ///must be called before using this function. |
---|
[100] | 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 | /// |
---|
[421] | 730 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
[244] | 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 |
---|
[763] | 738 | ///arcs, which form the DFS tree (forest). |
---|
[244] | 739 | /// |
---|
[421] | 740 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
[100] | 741 | ///must be called before using this function. |
---|
| 742 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 743 | |
---|
[763] | 744 | ///Checks if the given node. node is reached from the root(s). |
---|
[100] | 745 | |
---|
[421] | 746 | ///Returns \c true if \c v is reached from the root(s). |
---|
| 747 | /// |
---|
| 748 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
[100] | 749 | ///must be called before using this function. |
---|
[244] | 750 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[209] | 751 | |
---|
[100] | 752 | ///@} |
---|
| 753 | }; |
---|
| 754 | |
---|
[244] | 755 | ///Default traits class of dfs() function. |
---|
[100] | 756 | |
---|
[244] | 757 | ///Default traits class of dfs() function. |
---|
[157] | 758 | ///\tparam GR Digraph type. |
---|
[100] | 759 | template<class GR> |
---|
| 760 | struct DfsWizardDefaultTraits |
---|
| 761 | { |
---|
[244] | 762 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 763 | typedef GR Digraph; |
---|
[244] | 764 | |
---|
| 765 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 766 | ///arcs of the %DFS paths. |
---|
[209] | 767 | /// |
---|
[244] | 768 | ///The type of the map that stores the predecessor |
---|
[100] | 769 | ///arcs of the %DFS paths. |
---|
[763] | 770 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 771 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
---|
[301] | 772 | ///Instantiates a PredMap. |
---|
[209] | 773 | |
---|
[301] | 774 | ///This function instantiates a PredMap. |
---|
[244] | 775 | ///\param g is the digraph, to which we would like to define the |
---|
[301] | 776 | ///PredMap. |
---|
[244] | 777 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 778 | { |
---|
[278] | 779 | return new PredMap(g); |
---|
[100] | 780 | } |
---|
| 781 | |
---|
| 782 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 783 | |
---|
[100] | 784 | ///The type of the map that indicates which nodes are processed. |
---|
[763] | 785 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
---|
[833] | 786 | ///By default, it is a NullMap. |
---|
[100] | 787 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[301] | 788 | ///Instantiates a ProcessedMap. |
---|
[209] | 789 | |
---|
[301] | 790 | ///This function instantiates a ProcessedMap. |
---|
[100] | 791 | ///\param g is the digraph, to which |
---|
[301] | 792 | ///we would like to define the ProcessedMap. |
---|
[100] | 793 | #ifdef DOXYGEN |
---|
[244] | 794 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 795 | #else |
---|
[244] | 796 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 797 | #endif |
---|
| 798 | { |
---|
| 799 | return new ProcessedMap(); |
---|
| 800 | } |
---|
[244] | 801 | |
---|
[100] | 802 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 803 | |
---|
[100] | 804 | ///The type of the map that indicates which nodes are reached. |
---|
[763] | 805 | ///It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 806 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[301] | 807 | ///Instantiates a ReachedMap. |
---|
[209] | 808 | |
---|
[301] | 809 | ///This function instantiates a ReachedMap. |
---|
[244] | 810 | ///\param g is the digraph, to which |
---|
[301] | 811 | ///we would like to define the ReachedMap. |
---|
[244] | 812 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 813 | { |
---|
[244] | 814 | return new ReachedMap(g); |
---|
[100] | 815 | } |
---|
[209] | 816 | |
---|
[244] | 817 | ///The type of the map that stores the distances of the nodes. |
---|
| 818 | |
---|
| 819 | ///The type of the map that stores the distances of the nodes. |
---|
[763] | 820 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 821 | typedef typename Digraph::template NodeMap<int> DistMap; |
---|
[301] | 822 | ///Instantiates a DistMap. |
---|
[209] | 823 | |
---|
[301] | 824 | ///This function instantiates a DistMap. |
---|
[210] | 825 | ///\param g is the digraph, to which we would like to define |
---|
[301] | 826 | ///the DistMap |
---|
[244] | 827 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 828 | { |
---|
[278] | 829 | return new DistMap(g); |
---|
[100] | 830 | } |
---|
[278] | 831 | |
---|
| 832 | ///The type of the DFS paths. |
---|
| 833 | |
---|
| 834 | ///The type of the DFS paths. |
---|
[763] | 835 | ///It must conform to the \ref concepts::Path "Path" concept. |
---|
[278] | 836 | typedef lemon::Path<Digraph> Path; |
---|
[100] | 837 | }; |
---|
[209] | 838 | |
---|
[313] | 839 | /// Default traits class used by DfsWizard |
---|
[100] | 840 | |
---|
[763] | 841 | /// Default traits class used by DfsWizard. |
---|
| 842 | /// \tparam GR The type of the digraph. |
---|
[100] | 843 | template<class GR> |
---|
| 844 | class DfsWizardBase : public DfsWizardDefaultTraits<GR> |
---|
| 845 | { |
---|
| 846 | |
---|
| 847 | typedef DfsWizardDefaultTraits<GR> Base; |
---|
| 848 | protected: |
---|
[244] | 849 | //The type of the nodes in the digraph. |
---|
[100] | 850 | typedef typename Base::Digraph::Node Node; |
---|
| 851 | |
---|
[244] | 852 | //Pointer to the digraph the algorithm runs on. |
---|
[100] | 853 | void *_g; |
---|
[244] | 854 | //Pointer to the map of reached nodes. |
---|
[100] | 855 | void *_reached; |
---|
[244] | 856 | //Pointer to the map of processed nodes. |
---|
[100] | 857 | void *_processed; |
---|
[244] | 858 | //Pointer to the map of predecessors arcs. |
---|
[100] | 859 | void *_pred; |
---|
[244] | 860 | //Pointer to the map of distances. |
---|
[100] | 861 | void *_dist; |
---|
[278] | 862 | //Pointer to the DFS path to the target node. |
---|
| 863 | void *_path; |
---|
| 864 | //Pointer to the distance of the target node. |
---|
| 865 | int *_di; |
---|
[209] | 866 | |
---|
[100] | 867 | public: |
---|
| 868 | /// Constructor. |
---|
[209] | 869 | |
---|
[763] | 870 | /// This constructor does not require parameters, it initiates |
---|
[278] | 871 | /// all of the attributes to \c 0. |
---|
[100] | 872 | DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[278] | 873 | _dist(0), _path(0), _di(0) {} |
---|
[100] | 874 | |
---|
| 875 | /// Constructor. |
---|
[209] | 876 | |
---|
[278] | 877 | /// This constructor requires one parameter, |
---|
| 878 | /// others are initiated to \c 0. |
---|
[244] | 879 | /// \param g The digraph the algorithm runs on. |
---|
[278] | 880 | DfsWizardBase(const GR &g) : |
---|
[209] | 881 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
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[278] | 882 | _reached(0), _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
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[100] | 883 | |
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| 884 | }; |
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[209] | 885 | |
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[278] | 886 | /// Auxiliary class for the function-type interface of DFS algorithm. |
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[100] | 887 | |
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[278] | 888 | /// This auxiliary class is created to implement the |
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| 889 | /// \ref dfs() "function-type interface" of \ref Dfs algorithm. |
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[421] | 890 | /// It does not have own \ref run(Node) "run()" method, it uses the |
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| 891 | /// functions and features of the plain \ref Dfs. |
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[100] | 892 | /// |
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[278] | 893 | /// This class should only be used through the \ref dfs() function, |
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| 894 | /// which makes it easier to use the algorithm. |
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[891] | 895 | /// |
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| 896 | /// \tparam TR The traits class that defines various types used by the |
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| 897 | /// algorithm. |
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[100] | 898 | template<class TR> |
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| 899 | class DfsWizard : public TR |
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| 900 | { |
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| 901 | typedef TR Base; |
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| 902 | |
---|
| 903 | typedef typename TR::Digraph Digraph; |
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[244] | 904 | |
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[100] | 905 | typedef typename Digraph::Node Node; |
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| 906 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 907 | typedef typename Digraph::Arc Arc; |
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| 908 | typedef typename Digraph::OutArcIt OutArcIt; |
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[209] | 909 | |
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[244] | 910 | typedef typename TR::PredMap PredMap; |
---|
| 911 | typedef typename TR::DistMap DistMap; |
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[100] | 912 | typedef typename TR::ReachedMap ReachedMap; |
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| 913 | typedef typename TR::ProcessedMap ProcessedMap; |
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[278] | 914 | typedef typename TR::Path Path; |
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[100] | 915 | |
---|
| 916 | public: |
---|
[244] | 917 | |
---|
[100] | 918 | /// Constructor. |
---|
| 919 | DfsWizard() : TR() {} |
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| 920 | |
---|
| 921 | /// Constructor that requires parameters. |
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| 922 | |
---|
| 923 | /// Constructor that requires parameters. |
---|
| 924 | /// These parameters will be the default values for the traits class. |
---|
[278] | 925 | /// \param g The digraph the algorithm runs on. |
---|
| 926 | DfsWizard(const Digraph &g) : |
---|
| 927 | TR(g) {} |
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[100] | 928 | |
---|
| 929 | ///Copy constructor |
---|
| 930 | DfsWizard(const TR &b) : TR(b) {} |
---|
| 931 | |
---|
| 932 | ~DfsWizard() {} |
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| 933 | |
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[278] | 934 | ///Runs DFS algorithm from the given source node. |
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[209] | 935 | |
---|
[278] | 936 | ///This method runs DFS algorithm from node \c s |
---|
| 937 | ///in order to compute the DFS path to each node. |
---|
| 938 | void run(Node s) |
---|
| 939 | { |
---|
| 940 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 941 | if (Base::_pred) |
---|
| 942 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
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| 943 | if (Base::_dist) |
---|
| 944 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
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| 945 | if (Base::_reached) |
---|
| 946 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
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| 947 | if (Base::_processed) |
---|
| 948 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 949 | if (s!=INVALID) |
---|
| 950 | alg.run(s); |
---|
| 951 | else |
---|
| 952 | alg.run(); |
---|
| 953 | } |
---|
| 954 | |
---|
| 955 | ///Finds the DFS path between \c s and \c t. |
---|
| 956 | |
---|
| 957 | ///This method runs DFS algorithm from node \c s |
---|
| 958 | ///in order to compute the DFS path to node \c t |
---|
| 959 | ///(it stops searching when \c t is processed). |
---|
| 960 | /// |
---|
| 961 | ///\return \c true if \c t is reachable form \c s. |
---|
| 962 | bool run(Node s, Node t) |
---|
| 963 | { |
---|
| 964 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 965 | if (Base::_pred) |
---|
| 966 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 967 | if (Base::_dist) |
---|
| 968 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 969 | if (Base::_reached) |
---|
| 970 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 971 | if (Base::_processed) |
---|
| 972 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 973 | alg.run(s,t); |
---|
| 974 | if (Base::_path) |
---|
| 975 | *reinterpret_cast<Path*>(Base::_path) = alg.path(t); |
---|
| 976 | if (Base::_di) |
---|
| 977 | *Base::_di = alg.dist(t); |
---|
| 978 | return alg.reached(t); |
---|
| 979 | } |
---|
| 980 | |
---|
| 981 | ///Runs DFS algorithm to visit all nodes in the digraph. |
---|
| 982 | |
---|
[834] | 983 | ///This method runs DFS algorithm in order to visit all nodes |
---|
| 984 | ///in the digraph. |
---|
[100] | 985 | void run() |
---|
| 986 | { |
---|
[278] | 987 | run(INVALID); |
---|
[244] | 988 | } |
---|
| 989 | |
---|
[100] | 990 | template<class T> |
---|
[257] | 991 | struct SetPredMapBase : public Base { |
---|
[100] | 992 | typedef T PredMap; |
---|
| 993 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
[257] | 994 | SetPredMapBase(const TR &b) : TR(b) {} |
---|
[100] | 995 | }; |
---|
[763] | 996 | |
---|
| 997 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
| 998 | ///the predecessor map. |
---|
[100] | 999 | /// |
---|
[763] | 1000 | ///\ref named-templ-param "Named parameter" function for setting |
---|
| 1001 | ///the map that stores the predecessor arcs of the nodes. |
---|
[100] | 1002 | template<class T> |
---|
[257] | 1003 | DfsWizard<SetPredMapBase<T> > predMap(const T &t) |
---|
[100] | 1004 | { |
---|
| 1005 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1006 | return DfsWizard<SetPredMapBase<T> >(*this); |
---|
[100] | 1007 | } |
---|
[209] | 1008 | |
---|
[100] | 1009 | template<class T> |
---|
[257] | 1010 | struct SetReachedMapBase : public Base { |
---|
[100] | 1011 | typedef T ReachedMap; |
---|
| 1012 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
[257] | 1013 | SetReachedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1014 | }; |
---|
[763] | 1015 | |
---|
| 1016 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
| 1017 | ///the reached map. |
---|
[100] | 1018 | /// |
---|
[763] | 1019 | ///\ref named-templ-param "Named parameter" function for setting |
---|
| 1020 | ///the map that indicates which nodes are reached. |
---|
[100] | 1021 | template<class T> |
---|
[257] | 1022 | DfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
---|
[100] | 1023 | { |
---|
[158] | 1024 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1025 | return DfsWizard<SetReachedMapBase<T> >(*this); |
---|
[100] | 1026 | } |
---|
[209] | 1027 | |
---|
[100] | 1028 | template<class T> |
---|
[278] | 1029 | struct SetDistMapBase : public Base { |
---|
| 1030 | typedef T DistMap; |
---|
| 1031 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
| 1032 | SetDistMapBase(const TR &b) : TR(b) {} |
---|
| 1033 | }; |
---|
[763] | 1034 | |
---|
| 1035 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
| 1036 | ///the distance map. |
---|
[278] | 1037 | /// |
---|
[763] | 1038 | ///\ref named-templ-param "Named parameter" function for setting |
---|
| 1039 | ///the map that stores the distances of the nodes calculated |
---|
| 1040 | ///by the algorithm. |
---|
[278] | 1041 | template<class T> |
---|
| 1042 | DfsWizard<SetDistMapBase<T> > distMap(const T &t) |
---|
| 1043 | { |
---|
| 1044 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1045 | return DfsWizard<SetDistMapBase<T> >(*this); |
---|
| 1046 | } |
---|
| 1047 | |
---|
| 1048 | template<class T> |
---|
[257] | 1049 | struct SetProcessedMapBase : public Base { |
---|
[100] | 1050 | typedef T ProcessedMap; |
---|
| 1051 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
[257] | 1052 | SetProcessedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1053 | }; |
---|
[763] | 1054 | |
---|
| 1055 | ///\brief \ref named-func-param "Named parameter" for setting |
---|
| 1056 | ///the processed map. |
---|
[100] | 1057 | /// |
---|
[763] | 1058 | ///\ref named-templ-param "Named parameter" function for setting |
---|
| 1059 | ///the map that indicates which nodes are processed. |
---|
[100] | 1060 | template<class T> |
---|
[257] | 1061 | DfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
---|
[100] | 1062 | { |
---|
[158] | 1063 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1064 | return DfsWizard<SetProcessedMapBase<T> >(*this); |
---|
[100] | 1065 | } |
---|
[209] | 1066 | |
---|
[100] | 1067 | template<class T> |
---|
[278] | 1068 | struct SetPathBase : public Base { |
---|
| 1069 | typedef T Path; |
---|
| 1070 | SetPathBase(const TR &b) : TR(b) {} |
---|
[100] | 1071 | }; |
---|
[278] | 1072 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1073 | ///for getting the DFS path to the target node. |
---|
[100] | 1074 | /// |
---|
[278] | 1075 | ///\ref named-func-param "Named parameter" |
---|
| 1076 | ///for getting the DFS path to the target node. |
---|
[100] | 1077 | template<class T> |
---|
[278] | 1078 | DfsWizard<SetPathBase<T> > path(const T &t) |
---|
[100] | 1079 | { |
---|
[278] | 1080 | Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1081 | return DfsWizard<SetPathBase<T> >(*this); |
---|
| 1082 | } |
---|
| 1083 | |
---|
| 1084 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1085 | ///for getting the distance of the target node. |
---|
| 1086 | /// |
---|
| 1087 | ///\ref named-func-param "Named parameter" |
---|
| 1088 | ///for getting the distance of the target node. |
---|
| 1089 | DfsWizard dist(const int &d) |
---|
| 1090 | { |
---|
| 1091 | Base::_di=const_cast<int*>(&d); |
---|
| 1092 | return *this; |
---|
[100] | 1093 | } |
---|
[209] | 1094 | |
---|
[100] | 1095 | }; |
---|
[209] | 1096 | |
---|
[278] | 1097 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1098 | |
---|
| 1099 | ///\ingroup search |
---|
[278] | 1100 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1101 | /// |
---|
[278] | 1102 | ///This function also has several \ref named-func-param "named parameters", |
---|
[100] | 1103 | ///they are declared as the members of class \ref DfsWizard. |
---|
[278] | 1104 | ///The following examples show how to use these parameters. |
---|
[100] | 1105 | ///\code |
---|
[278] | 1106 | /// // Compute the DFS tree |
---|
| 1107 | /// dfs(g).predMap(preds).distMap(dists).run(s); |
---|
| 1108 | /// |
---|
| 1109 | /// // Compute the DFS path from s to t |
---|
| 1110 | /// bool reached = dfs(g).path(p).dist(d).run(s,t); |
---|
[100] | 1111 | ///\endcode |
---|
[421] | 1112 | ///\warning Don't forget to put the \ref DfsWizard::run(Node) "run()" |
---|
[100] | 1113 | ///to the end of the parameter list. |
---|
| 1114 | ///\sa DfsWizard |
---|
| 1115 | ///\sa Dfs |
---|
| 1116 | template<class GR> |
---|
| 1117 | DfsWizard<DfsWizardBase<GR> > |
---|
[278] | 1118 | dfs(const GR &digraph) |
---|
[100] | 1119 | { |
---|
[278] | 1120 | return DfsWizard<DfsWizardBase<GR> >(digraph); |
---|
[100] | 1121 | } |
---|
| 1122 | |
---|
| 1123 | #ifdef DOXYGEN |
---|
[244] | 1124 | /// \brief Visitor class for DFS. |
---|
[209] | 1125 | /// |
---|
[244] | 1126 | /// This class defines the interface of the DfsVisit events, and |
---|
| 1127 | /// it could be the base of a real visitor class. |
---|
[525] | 1128 | template <typename GR> |
---|
[100] | 1129 | struct DfsVisitor { |
---|
[525] | 1130 | typedef GR Digraph; |
---|
[100] | 1131 | typedef typename Digraph::Arc Arc; |
---|
| 1132 | typedef typename Digraph::Node Node; |
---|
[244] | 1133 | /// \brief Called for the source node of the DFS. |
---|
[209] | 1134 | /// |
---|
[244] | 1135 | /// This function is called for the source node of the DFS. |
---|
| 1136 | void start(const Node& node) {} |
---|
| 1137 | /// \brief Called when the source node is leaved. |
---|
| 1138 | /// |
---|
| 1139 | /// This function is called when the source node is leaved. |
---|
| 1140 | void stop(const Node& node) {} |
---|
| 1141 | /// \brief Called when a node is reached first time. |
---|
| 1142 | /// |
---|
| 1143 | /// This function is called when a node is reached first time. |
---|
| 1144 | void reach(const Node& node) {} |
---|
| 1145 | /// \brief Called when an arc reaches a new node. |
---|
| 1146 | /// |
---|
| 1147 | /// This function is called when the DFS finds an arc whose target node |
---|
| 1148 | /// is not reached yet. |
---|
[100] | 1149 | void discover(const Arc& arc) {} |
---|
[244] | 1150 | /// \brief Called when an arc is examined but its target node is |
---|
[100] | 1151 | /// already discovered. |
---|
[209] | 1152 | /// |
---|
[244] | 1153 | /// This function is called when an arc is examined but its target node is |
---|
[100] | 1154 | /// already discovered. |
---|
| 1155 | void examine(const Arc& arc) {} |
---|
[244] | 1156 | /// \brief Called when the DFS steps back from a node. |
---|
[209] | 1157 | /// |
---|
[244] | 1158 | /// This function is called when the DFS steps back from a node. |
---|
| 1159 | void leave(const Node& node) {} |
---|
| 1160 | /// \brief Called when the DFS steps back on an arc. |
---|
[209] | 1161 | /// |
---|
[244] | 1162 | /// This function is called when the DFS steps back on an arc. |
---|
| 1163 | void backtrack(const Arc& arc) {} |
---|
[100] | 1164 | }; |
---|
| 1165 | #else |
---|
[525] | 1166 | template <typename GR> |
---|
[100] | 1167 | struct DfsVisitor { |
---|
[525] | 1168 | typedef GR Digraph; |
---|
[100] | 1169 | typedef typename Digraph::Arc Arc; |
---|
| 1170 | typedef typename Digraph::Node Node; |
---|
| 1171 | void start(const Node&) {} |
---|
| 1172 | void stop(const Node&) {} |
---|
[244] | 1173 | void reach(const Node&) {} |
---|
| 1174 | void discover(const Arc&) {} |
---|
| 1175 | void examine(const Arc&) {} |
---|
| 1176 | void leave(const Node&) {} |
---|
| 1177 | void backtrack(const Arc&) {} |
---|
[100] | 1178 | |
---|
| 1179 | template <typename _Visitor> |
---|
| 1180 | struct Constraints { |
---|
| 1181 | void constraints() { |
---|
[209] | 1182 | Arc arc; |
---|
| 1183 | Node node; |
---|
| 1184 | visitor.start(node); |
---|
| 1185 | visitor.stop(arc); |
---|
[244] | 1186 | visitor.reach(node); |
---|
| 1187 | visitor.discover(arc); |
---|
| 1188 | visitor.examine(arc); |
---|
| 1189 | visitor.leave(node); |
---|
| 1190 | visitor.backtrack(arc); |
---|
[100] | 1191 | } |
---|
| 1192 | _Visitor& visitor; |
---|
| 1193 | }; |
---|
| 1194 | }; |
---|
| 1195 | #endif |
---|
| 1196 | |
---|
| 1197 | /// \brief Default traits class of DfsVisit class. |
---|
| 1198 | /// |
---|
| 1199 | /// Default traits class of DfsVisit class. |
---|
[244] | 1200 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[525] | 1201 | template<class GR> |
---|
[100] | 1202 | struct DfsVisitDefaultTraits { |
---|
| 1203 | |
---|
[244] | 1204 | /// \brief The type of the digraph the algorithm runs on. |
---|
[525] | 1205 | typedef GR Digraph; |
---|
[100] | 1206 | |
---|
| 1207 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1208 | /// |
---|
[100] | 1209 | /// The type of the map that indicates which nodes are reached. |
---|
[763] | 1210 | /// It must conform to the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 1211 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1212 | |
---|
[301] | 1213 | /// \brief Instantiates a ReachedMap. |
---|
[100] | 1214 | /// |
---|
[301] | 1215 | /// This function instantiates a ReachedMap. |
---|
[100] | 1216 | /// \param digraph is the digraph, to which |
---|
[301] | 1217 | /// we would like to define the ReachedMap. |
---|
[100] | 1218 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1219 | return new ReachedMap(digraph); |
---|
| 1220 | } |
---|
| 1221 | |
---|
| 1222 | }; |
---|
[209] | 1223 | |
---|
[100] | 1224 | /// \ingroup search |
---|
[244] | 1225 | /// |
---|
[525] | 1226 | /// \brief DFS algorithm class with visitor interface. |
---|
[244] | 1227 | /// |
---|
[525] | 1228 | /// This class provides an efficient implementation of the DFS algorithm |
---|
[100] | 1229 | /// with visitor interface. |
---|
| 1230 | /// |
---|
[525] | 1231 | /// The DfsVisit class provides an alternative interface to the Dfs |
---|
[100] | 1232 | /// class. It works with callback mechanism, the DfsVisit object calls |
---|
[244] | 1233 | /// the member functions of the \c Visitor class on every DFS event. |
---|
[100] | 1234 | /// |
---|
[252] | 1235 | /// This interface of the DFS algorithm should be used in special cases |
---|
| 1236 | /// when extra actions have to be performed in connection with certain |
---|
| 1237 | /// events of the DFS algorithm. Otherwise consider to use Dfs or dfs() |
---|
| 1238 | /// instead. |
---|
| 1239 | /// |
---|
[525] | 1240 | /// \tparam GR The type of the digraph the algorithm runs on. |
---|
| 1241 | /// The default type is \ref ListDigraph. |
---|
| 1242 | /// The value of GR is not used directly by \ref DfsVisit, |
---|
| 1243 | /// it is only passed to \ref DfsVisitDefaultTraits. |
---|
| 1244 | /// \tparam VS The Visitor type that is used by the algorithm. |
---|
| 1245 | /// \ref DfsVisitor "DfsVisitor<GR>" is an empty visitor, which |
---|
[244] | 1246 | /// does not observe the DFS events. If you want to observe the DFS |
---|
| 1247 | /// events, you should implement your own visitor class. |
---|
[891] | 1248 | /// \tparam TR The traits class that defines various types used by the |
---|
| 1249 | /// algorithm. By default, it is \ref DfsVisitDefaultTraits |
---|
| 1250 | /// "DfsVisitDefaultTraits<GR>". |
---|
| 1251 | /// In most cases, this parameter should not be set directly, |
---|
| 1252 | /// consider to use the named template parameters instead. |
---|
[100] | 1253 | #ifdef DOXYGEN |
---|
[525] | 1254 | template <typename GR, typename VS, typename TR> |
---|
[100] | 1255 | #else |
---|
[525] | 1256 | template <typename GR = ListDigraph, |
---|
| 1257 | typename VS = DfsVisitor<GR>, |
---|
| 1258 | typename TR = DfsVisitDefaultTraits<GR> > |
---|
[100] | 1259 | #endif |
---|
| 1260 | class DfsVisit { |
---|
| 1261 | public: |
---|
[209] | 1262 | |
---|
[244] | 1263 | ///The traits class. |
---|
[525] | 1264 | typedef TR Traits; |
---|
[100] | 1265 | |
---|
[244] | 1266 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 1267 | typedef typename Traits::Digraph Digraph; |
---|
| 1268 | |
---|
[244] | 1269 | ///The visitor type used by the algorithm. |
---|
[525] | 1270 | typedef VS Visitor; |
---|
[100] | 1271 | |
---|
[244] | 1272 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 1273 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1274 | |
---|
| 1275 | private: |
---|
| 1276 | |
---|
| 1277 | typedef typename Digraph::Node Node; |
---|
| 1278 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1279 | typedef typename Digraph::Arc Arc; |
---|
| 1280 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1281 | |
---|
[244] | 1282 | //Pointer to the underlying digraph. |
---|
[100] | 1283 | const Digraph *_digraph; |
---|
[244] | 1284 | //Pointer to the visitor object. |
---|
[100] | 1285 | Visitor *_visitor; |
---|
[244] | 1286 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 1287 | ReachedMap *_reached; |
---|
[244] | 1288 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 1289 | bool local_reached; |
---|
| 1290 | |
---|
| 1291 | std::vector<typename Digraph::Arc> _stack; |
---|
| 1292 | int _stack_head; |
---|
| 1293 | |
---|
[280] | 1294 | //Creates the maps if necessary. |
---|
[100] | 1295 | void create_maps() { |
---|
| 1296 | if(!_reached) { |
---|
[209] | 1297 | local_reached = true; |
---|
| 1298 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1299 | } |
---|
| 1300 | } |
---|
| 1301 | |
---|
| 1302 | protected: |
---|
| 1303 | |
---|
| 1304 | DfsVisit() {} |
---|
[209] | 1305 | |
---|
[100] | 1306 | public: |
---|
| 1307 | |
---|
| 1308 | typedef DfsVisit Create; |
---|
| 1309 | |
---|
[421] | 1310 | /// \name Named Template Parameters |
---|
[100] | 1311 | |
---|
| 1312 | ///@{ |
---|
| 1313 | template <class T> |
---|
[257] | 1314 | struct SetReachedMapTraits : public Traits { |
---|
[100] | 1315 | typedef T ReachedMap; |
---|
| 1316 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
[290] | 1317 | LEMON_ASSERT(false, "ReachedMap is not initialized"); |
---|
| 1318 | return 0; // ignore warnings |
---|
[100] | 1319 | } |
---|
| 1320 | }; |
---|
[209] | 1321 | /// \brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 1322 | /// ReachedMap type. |
---|
[100] | 1323 | /// |
---|
[244] | 1324 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
---|
[100] | 1325 | template <class T> |
---|
[257] | 1326 | struct SetReachedMap : public DfsVisit< Digraph, Visitor, |
---|
| 1327 | SetReachedMapTraits<T> > { |
---|
| 1328 | typedef DfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
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[100] | 1329 | }; |
---|
| 1330 | ///@} |
---|
| 1331 | |
---|
[209] | 1332 | public: |
---|
| 1333 | |
---|
[100] | 1334 | /// \brief Constructor. |
---|
| 1335 | /// |
---|
| 1336 | /// Constructor. |
---|
| 1337 | /// |
---|
[244] | 1338 | /// \param digraph The digraph the algorithm runs on. |
---|
| 1339 | /// \param visitor The visitor object of the algorithm. |
---|
[209] | 1340 | DfsVisit(const Digraph& digraph, Visitor& visitor) |
---|
[100] | 1341 | : _digraph(&digraph), _visitor(&visitor), |
---|
[209] | 1342 | _reached(0), local_reached(false) {} |
---|
| 1343 | |
---|
[100] | 1344 | /// \brief Destructor. |
---|
| 1345 | ~DfsVisit() { |
---|
| 1346 | if(local_reached) delete _reached; |
---|
| 1347 | } |
---|
| 1348 | |
---|
[244] | 1349 | /// \brief Sets the map that indicates which nodes are reached. |
---|
[100] | 1350 | /// |
---|
[244] | 1351 | /// Sets the map that indicates which nodes are reached. |
---|
[421] | 1352 | /// If you don't use this function before calling \ref run(Node) "run()" |
---|
| 1353 | /// or \ref init(), an instance will be allocated automatically. |
---|
| 1354 | /// The destructor deallocates this automatically allocated map, |
---|
| 1355 | /// of course. |
---|
[100] | 1356 | /// \return <tt> (*this) </tt> |
---|
| 1357 | DfsVisit &reachedMap(ReachedMap &m) { |
---|
| 1358 | if(local_reached) { |
---|
[209] | 1359 | delete _reached; |
---|
| 1360 | local_reached=false; |
---|
[100] | 1361 | } |
---|
| 1362 | _reached = &m; |
---|
| 1363 | return *this; |
---|
| 1364 | } |
---|
| 1365 | |
---|
| 1366 | public: |
---|
[244] | 1367 | |
---|
[421] | 1368 | /// \name Execution Control |
---|
| 1369 | /// The simplest way to execute the DFS algorithm is to use one of the |
---|
| 1370 | /// member functions called \ref run(Node) "run()".\n |
---|
[760] | 1371 | /// If you need better control on the execution, you have to call |
---|
| 1372 | /// \ref init() first, then you can add a source node with \ref addSource() |
---|
[421] | 1373 | /// and perform the actual computation with \ref start(). |
---|
| 1374 | /// This procedure can be repeated if there are nodes that have not |
---|
| 1375 | /// been reached. |
---|
[100] | 1376 | |
---|
| 1377 | /// @{ |
---|
[244] | 1378 | |
---|
[100] | 1379 | /// \brief Initializes the internal data structures. |
---|
| 1380 | /// |
---|
| 1381 | /// Initializes the internal data structures. |
---|
| 1382 | void init() { |
---|
| 1383 | create_maps(); |
---|
| 1384 | _stack.resize(countNodes(*_digraph)); |
---|
| 1385 | _stack_head = -1; |
---|
| 1386 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
---|
[209] | 1387 | _reached->set(u, false); |
---|
[100] | 1388 | } |
---|
| 1389 | } |
---|
[209] | 1390 | |
---|
[421] | 1391 | /// \brief Adds a new source node. |
---|
[100] | 1392 | /// |
---|
[421] | 1393 | /// Adds a new source node to the set of nodes to be processed. |
---|
[244] | 1394 | /// |
---|
[421] | 1395 | /// \pre The stack must be empty. Otherwise the algorithm gives |
---|
| 1396 | /// wrong results. (One of the outgoing arcs of all the source nodes |
---|
| 1397 | /// except for the last one will not be visited and distances will |
---|
| 1398 | /// also be wrong.) |
---|
[244] | 1399 | void addSource(Node s) |
---|
| 1400 | { |
---|
| 1401 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
---|
[100] | 1402 | if(!(*_reached)[s]) { |
---|
[209] | 1403 | _reached->set(s,true); |
---|
| 1404 | _visitor->start(s); |
---|
| 1405 | _visitor->reach(s); |
---|
| 1406 | Arc e; |
---|
| 1407 | _digraph->firstOut(e, s); |
---|
| 1408 | if (e != INVALID) { |
---|
| 1409 | _stack[++_stack_head] = e; |
---|
| 1410 | } else { |
---|
| 1411 | _visitor->leave(s); |
---|
[435] | 1412 | _visitor->stop(s); |
---|
[209] | 1413 | } |
---|
| 1414 | } |
---|
[100] | 1415 | } |
---|
[209] | 1416 | |
---|
[100] | 1417 | /// \brief Processes the next arc. |
---|
| 1418 | /// |
---|
| 1419 | /// Processes the next arc. |
---|
| 1420 | /// |
---|
| 1421 | /// \return The processed arc. |
---|
| 1422 | /// |
---|
[244] | 1423 | /// \pre The stack must not be empty. |
---|
[209] | 1424 | Arc processNextArc() { |
---|
[100] | 1425 | Arc e = _stack[_stack_head]; |
---|
| 1426 | Node m = _digraph->target(e); |
---|
| 1427 | if(!(*_reached)[m]) { |
---|
[209] | 1428 | _visitor->discover(e); |
---|
| 1429 | _visitor->reach(m); |
---|
| 1430 | _reached->set(m, true); |
---|
| 1431 | _digraph->firstOut(_stack[++_stack_head], m); |
---|
[100] | 1432 | } else { |
---|
[209] | 1433 | _visitor->examine(e); |
---|
| 1434 | m = _digraph->source(e); |
---|
| 1435 | _digraph->nextOut(_stack[_stack_head]); |
---|
[100] | 1436 | } |
---|
| 1437 | while (_stack_head>=0 && _stack[_stack_head] == INVALID) { |
---|
[209] | 1438 | _visitor->leave(m); |
---|
| 1439 | --_stack_head; |
---|
| 1440 | if (_stack_head >= 0) { |
---|
| 1441 | _visitor->backtrack(_stack[_stack_head]); |
---|
| 1442 | m = _digraph->source(_stack[_stack_head]); |
---|
| 1443 | _digraph->nextOut(_stack[_stack_head]); |
---|
| 1444 | } else { |
---|
| 1445 | _visitor->stop(m); |
---|
| 1446 | } |
---|
[100] | 1447 | } |
---|
| 1448 | return e; |
---|
| 1449 | } |
---|
| 1450 | |
---|
| 1451 | /// \brief Next arc to be processed. |
---|
| 1452 | /// |
---|
| 1453 | /// Next arc to be processed. |
---|
| 1454 | /// |
---|
| 1455 | /// \return The next arc to be processed or INVALID if the stack is |
---|
| 1456 | /// empty. |
---|
[244] | 1457 | Arc nextArc() const { |
---|
[100] | 1458 | return _stack_head >= 0 ? _stack[_stack_head] : INVALID; |
---|
| 1459 | } |
---|
| 1460 | |
---|
| 1461 | /// \brief Returns \c false if there are nodes |
---|
[244] | 1462 | /// to be processed. |
---|
[100] | 1463 | /// |
---|
| 1464 | /// Returns \c false if there are nodes |
---|
[244] | 1465 | /// to be processed in the queue (stack). |
---|
| 1466 | bool emptyQueue() const { return _stack_head < 0; } |
---|
[100] | 1467 | |
---|
| 1468 | /// \brief Returns the number of the nodes to be processed. |
---|
| 1469 | /// |
---|
[244] | 1470 | /// Returns the number of the nodes to be processed in the queue (stack). |
---|
| 1471 | int queueSize() const { return _stack_head + 1; } |
---|
[209] | 1472 | |
---|
[100] | 1473 | /// \brief Executes the algorithm. |
---|
| 1474 | /// |
---|
| 1475 | /// Executes the algorithm. |
---|
| 1476 | /// |
---|
[244] | 1477 | /// This method runs the %DFS algorithm from the root node |
---|
| 1478 | /// in order to compute the %DFS path to each node. |
---|
| 1479 | /// |
---|
| 1480 | /// The algorithm computes |
---|
| 1481 | /// - the %DFS tree, |
---|
| 1482 | /// - the distance of each node from the root in the %DFS tree. |
---|
| 1483 | /// |
---|
| 1484 | /// \pre init() must be called and a root node should be |
---|
| 1485 | /// added with addSource() before using this function. |
---|
| 1486 | /// |
---|
| 1487 | /// \note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
| 1488 | /// \code |
---|
| 1489 | /// while ( !d.emptyQueue() ) { |
---|
| 1490 | /// d.processNextArc(); |
---|
| 1491 | /// } |
---|
| 1492 | /// \endcode |
---|
[100] | 1493 | void start() { |
---|
| 1494 | while ( !emptyQueue() ) processNextArc(); |
---|
| 1495 | } |
---|
[209] | 1496 | |
---|
[244] | 1497 | /// \brief Executes the algorithm until the given target node is reached. |
---|
[100] | 1498 | /// |
---|
[244] | 1499 | /// Executes the algorithm until the given target node is reached. |
---|
[100] | 1500 | /// |
---|
[244] | 1501 | /// This method runs the %DFS algorithm from the root node |
---|
[286] | 1502 | /// in order to compute the DFS path to \c t. |
---|
[244] | 1503 | /// |
---|
| 1504 | /// The algorithm computes |
---|
[286] | 1505 | /// - the %DFS path to \c t, |
---|
| 1506 | /// - the distance of \c t from the root in the %DFS tree. |
---|
[244] | 1507 | /// |
---|
| 1508 | /// \pre init() must be called and a root node should be added |
---|
[100] | 1509 | /// with addSource() before using this function. |
---|
[286] | 1510 | void start(Node t) { |
---|
| 1511 | while ( !emptyQueue() && _digraph->target(_stack[_stack_head]) != t ) |
---|
[209] | 1512 | processNextArc(); |
---|
[100] | 1513 | } |
---|
[209] | 1514 | |
---|
[100] | 1515 | /// \brief Executes the algorithm until a condition is met. |
---|
| 1516 | /// |
---|
| 1517 | /// Executes the algorithm until a condition is met. |
---|
| 1518 | /// |
---|
[244] | 1519 | /// This method runs the %DFS algorithm from the root node |
---|
| 1520 | /// until an arc \c a with <tt>am[a]</tt> true is found. |
---|
| 1521 | /// |
---|
| 1522 | /// \param am A \c bool (or convertible) arc map. The algorithm |
---|
| 1523 | /// will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
---|
| 1524 | /// |
---|
| 1525 | /// \return The reached arc \c a with <tt>am[a]</tt> true or |
---|
| 1526 | /// \c INVALID if no such arc was found. |
---|
| 1527 | /// |
---|
| 1528 | /// \pre init() must be called and a root node should be added |
---|
[100] | 1529 | /// with addSource() before using this function. |
---|
| 1530 | /// |
---|
[244] | 1531 | /// \warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
---|
[100] | 1532 | /// not a node map. |
---|
[244] | 1533 | template <typename AM> |
---|
| 1534 | Arc start(const AM &am) { |
---|
| 1535 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
---|
[100] | 1536 | processNextArc(); |
---|
| 1537 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
| 1538 | } |
---|
| 1539 | |
---|
[286] | 1540 | /// \brief Runs the algorithm from the given source node. |
---|
[100] | 1541 | /// |
---|
[244] | 1542 | /// This method runs the %DFS algorithm from node \c s. |
---|
| 1543 | /// in order to compute the DFS path to each node. |
---|
| 1544 | /// |
---|
| 1545 | /// The algorithm computes |
---|
| 1546 | /// - the %DFS tree, |
---|
| 1547 | /// - the distance of each node from the root in the %DFS tree. |
---|
| 1548 | /// |
---|
| 1549 | /// \note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1550 | ///\code |
---|
| 1551 | /// d.init(); |
---|
| 1552 | /// d.addSource(s); |
---|
| 1553 | /// d.start(); |
---|
| 1554 | ///\endcode |
---|
| 1555 | void run(Node s) { |
---|
| 1556 | init(); |
---|
| 1557 | addSource(s); |
---|
| 1558 | start(); |
---|
| 1559 | } |
---|
| 1560 | |
---|
[244] | 1561 | /// \brief Finds the %DFS path between \c s and \c t. |
---|
| 1562 | |
---|
| 1563 | /// This method runs the %DFS algorithm from node \c s |
---|
[286] | 1564 | /// in order to compute the DFS path to node \c t |
---|
| 1565 | /// (it stops searching when \c t is processed). |
---|
[244] | 1566 | /// |
---|
[286] | 1567 | /// \return \c true if \c t is reachable form \c s. |
---|
[244] | 1568 | /// |
---|
| 1569 | /// \note Apart from the return value, <tt>d.run(s,t)</tt> is |
---|
| 1570 | /// just a shortcut of the following code. |
---|
| 1571 | ///\code |
---|
| 1572 | /// d.init(); |
---|
| 1573 | /// d.addSource(s); |
---|
| 1574 | /// d.start(t); |
---|
| 1575 | ///\endcode |
---|
[286] | 1576 | bool run(Node s,Node t) { |
---|
[244] | 1577 | init(); |
---|
| 1578 | addSource(s); |
---|
| 1579 | start(t); |
---|
[286] | 1580 | return reached(t); |
---|
[244] | 1581 | } |
---|
| 1582 | |
---|
| 1583 | /// \brief Runs the algorithm to visit all nodes in the digraph. |
---|
[209] | 1584 | |
---|
[834] | 1585 | /// This method runs the %DFS algorithm in order to visit all nodes |
---|
| 1586 | /// in the digraph. |
---|
[244] | 1587 | /// |
---|
| 1588 | /// \note <tt>d.run()</tt> is just a shortcut of the following code. |
---|
[100] | 1589 | ///\code |
---|
[244] | 1590 | /// d.init(); |
---|
| 1591 | /// for (NodeIt n(digraph); n != INVALID; ++n) { |
---|
| 1592 | /// if (!d.reached(n)) { |
---|
| 1593 | /// d.addSource(n); |
---|
| 1594 | /// d.start(); |
---|
| 1595 | /// } |
---|
| 1596 | /// } |
---|
[100] | 1597 | ///\endcode |
---|
| 1598 | void run() { |
---|
| 1599 | init(); |
---|
| 1600 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
| 1601 | if (!reached(it)) { |
---|
| 1602 | addSource(it); |
---|
| 1603 | start(); |
---|
| 1604 | } |
---|
| 1605 | } |
---|
| 1606 | } |
---|
[244] | 1607 | |
---|
[100] | 1608 | ///@} |
---|
| 1609 | |
---|
| 1610 | /// \name Query Functions |
---|
[421] | 1611 | /// The results of the DFS algorithm can be obtained using these |
---|
[100] | 1612 | /// functions.\n |
---|
[421] | 1613 | /// Either \ref run(Node) "run()" or \ref start() should be called |
---|
| 1614 | /// before using them. |
---|
| 1615 | |
---|
[100] | 1616 | ///@{ |
---|
[244] | 1617 | |
---|
[763] | 1618 | /// \brief Checks if the given node is reached from the root(s). |
---|
[100] | 1619 | /// |
---|
[421] | 1620 | /// Returns \c true if \c v is reached from the root(s). |
---|
| 1621 | /// |
---|
| 1622 | /// \pre Either \ref run(Node) "run()" or \ref init() |
---|
[100] | 1623 | /// must be called before using this function. |
---|
[437] | 1624 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[244] | 1625 | |
---|
[100] | 1626 | ///@} |
---|
[244] | 1627 | |
---|
[100] | 1628 | }; |
---|
| 1629 | |
---|
| 1630 | } //END OF NAMESPACE LEMON |
---|
| 1631 | |
---|
| 1632 | #endif |
---|