[209] | 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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[100] | 2 | * |
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[209] | 3 | * This file is a part of LEMON, a generic C++ optimization library. |
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[100] | 4 | * |
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| 5 | * Copyright (C) 2003-2008 |
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| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | #ifndef LEMON_DFS_H |
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| 20 | #define LEMON_DFS_H |
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| 21 | |
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| 22 | ///\ingroup search |
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| 23 | ///\file |
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[244] | 24 | ///\brief DFS algorithm. |
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[100] | 25 | |
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| 26 | #include <lemon/list_graph.h> |
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| 27 | #include <lemon/bits/path_dump.h> |
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[220] | 28 | #include <lemon/core.h> |
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[100] | 29 | #include <lemon/error.h> |
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[244] | 30 | #include <lemon/assert.h> |
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[100] | 31 | #include <lemon/maps.h> |
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[278] | 32 | #include <lemon/path.h> |
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[100] | 33 | |
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| 34 | namespace lemon { |
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| 35 | |
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| 36 | ///Default traits class of Dfs class. |
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| 37 | |
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| 38 | ///Default traits class of Dfs class. |
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[157] | 39 | ///\tparam GR Digraph type. |
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[100] | 40 | template<class GR> |
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| 41 | struct DfsDefaultTraits |
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| 42 | { |
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[244] | 43 | ///The type of the digraph the algorithm runs on. |
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[100] | 44 | typedef GR Digraph; |
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[244] | 45 | |
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| 46 | ///\brief The type of the map that stores the predecessor |
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[100] | 47 | ///arcs of the %DFS paths. |
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[209] | 48 | /// |
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[244] | 49 | ///The type of the map that stores the predecessor |
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[100] | 50 | ///arcs of the %DFS paths. |
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| 51 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[244] | 52 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
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| 53 | ///Instantiates a \ref PredMap. |
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[209] | 54 | |
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| 55 | ///This function instantiates a \ref PredMap. |
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[244] | 56 | ///\param g is the digraph, to which we would like to define the |
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| 57 | ///\ref PredMap. |
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| 58 | static PredMap *createPredMap(const Digraph &g) |
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[100] | 59 | { |
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[244] | 60 | return new PredMap(g); |
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[100] | 61 | } |
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| 62 | |
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| 63 | ///The type of the map that indicates which nodes are processed. |
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[209] | 64 | |
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[100] | 65 | ///The type of the map that indicates which nodes are processed. |
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| 66 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 67 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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[244] | 68 | ///Instantiates a \ref ProcessedMap. |
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[209] | 69 | |
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| 70 | ///This function instantiates a \ref ProcessedMap. |
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[100] | 71 | ///\param g is the digraph, to which |
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| 72 | ///we would like to define the \ref ProcessedMap |
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| 73 | #ifdef DOXYGEN |
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[244] | 74 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 75 | #else |
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[244] | 76 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 77 | #endif |
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| 78 | { |
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| 79 | return new ProcessedMap(); |
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| 80 | } |
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[244] | 81 | |
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[100] | 82 | ///The type of the map that indicates which nodes are reached. |
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[209] | 83 | |
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[100] | 84 | ///The type of the map that indicates which nodes are reached. |
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[244] | 85 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 86 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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[244] | 87 | ///Instantiates a \ref ReachedMap. |
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[209] | 88 | |
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| 89 | ///This function instantiates a \ref ReachedMap. |
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[244] | 90 | ///\param g is the digraph, to which |
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[100] | 91 | ///we would like to define the \ref ReachedMap. |
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[244] | 92 | static ReachedMap *createReachedMap(const Digraph &g) |
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[100] | 93 | { |
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[244] | 94 | return new ReachedMap(g); |
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[100] | 95 | } |
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[209] | 96 | |
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[244] | 97 | ///The type of the map that stores the distances of the nodes. |
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| 98 | |
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| 99 | ///The type of the map that stores the distances of the nodes. |
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[100] | 100 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 101 | typedef typename Digraph::template NodeMap<int> DistMap; |
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[244] | 102 | ///Instantiates a \ref DistMap. |
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[209] | 103 | |
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| 104 | ///This function instantiates a \ref DistMap. |
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[244] | 105 | ///\param g is the digraph, to which we would like to define the |
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| 106 | ///\ref DistMap. |
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| 107 | static DistMap *createDistMap(const Digraph &g) |
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[100] | 108 | { |
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[244] | 109 | return new DistMap(g); |
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[100] | 110 | } |
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| 111 | }; |
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[209] | 112 | |
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[100] | 113 | ///%DFS algorithm class. |
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[209] | 114 | |
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[100] | 115 | ///\ingroup search |
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| 116 | ///This class provides an efficient implementation of the %DFS algorithm. |
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| 117 | /// |
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[278] | 118 | ///There is also a \ref dfs() "function-type interface" for the DFS |
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[244] | 119 | ///algorithm, which is convenient in the simplier cases and it can be |
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| 120 | ///used easier. |
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| 121 | /// |
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| 122 | ///\tparam GR The type of the digraph the algorithm runs on. |
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| 123 | ///The default value is \ref ListDigraph. The value of GR is not used |
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| 124 | ///directly by \ref Dfs, it is only passed to \ref DfsDefaultTraits. |
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[157] | 125 | ///\tparam TR Traits class to set various data types used by the algorithm. |
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[100] | 126 | ///The default traits class is |
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| 127 | ///\ref DfsDefaultTraits "DfsDefaultTraits<GR>". |
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| 128 | ///See \ref DfsDefaultTraits for the documentation of |
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| 129 | ///a Dfs traits class. |
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| 130 | #ifdef DOXYGEN |
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| 131 | template <typename GR, |
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[209] | 132 | typename TR> |
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[100] | 133 | #else |
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| 134 | template <typename GR=ListDigraph, |
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[209] | 135 | typename TR=DfsDefaultTraits<GR> > |
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[100] | 136 | #endif |
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| 137 | class Dfs { |
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| 138 | public: |
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[244] | 139 | ///\ref Exception for uninitialized parameters. |
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| 140 | |
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| 141 | ///This error represents problems in the initialization of the |
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| 142 | ///parameters of the algorithm. |
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[100] | 143 | class UninitializedParameter : public lemon::UninitializedParameter { |
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| 144 | public: |
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| 145 | virtual const char* what() const throw() { |
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[209] | 146 | return "lemon::Dfs::UninitializedParameter"; |
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[100] | 147 | } |
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| 148 | }; |
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| 149 | |
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[244] | 150 | ///The type of the digraph the algorithm runs on. |
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| 151 | typedef typename TR::Digraph Digraph; |
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| 152 | |
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| 153 | ///\brief The type of the map that stores the predecessor arcs of the |
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| 154 | ///DFS paths. |
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| 155 | typedef typename TR::PredMap PredMap; |
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| 156 | ///The type of the map that stores the distances of the nodes. |
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| 157 | typedef typename TR::DistMap DistMap; |
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| 158 | ///The type of the map that indicates which nodes are reached. |
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| 159 | typedef typename TR::ReachedMap ReachedMap; |
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| 160 | ///The type of the map that indicates which nodes are processed. |
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| 161 | typedef typename TR::ProcessedMap ProcessedMap; |
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| 162 | ///The type of the paths. |
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| 163 | typedef PredMapPath<Digraph, PredMap> Path; |
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| 164 | |
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| 165 | ///The traits class. |
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[100] | 166 | typedef TR Traits; |
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[244] | 167 | |
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| 168 | private: |
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| 169 | |
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[100] | 170 | typedef typename Digraph::Node Node; |
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| 171 | typedef typename Digraph::NodeIt NodeIt; |
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| 172 | typedef typename Digraph::Arc Arc; |
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| 173 | typedef typename Digraph::OutArcIt OutArcIt; |
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[209] | 174 | |
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[244] | 175 | //Pointer to the underlying digraph. |
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[100] | 176 | const Digraph *G; |
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[244] | 177 | //Pointer to the map of predecessor arcs. |
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[100] | 178 | PredMap *_pred; |
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[244] | 179 | //Indicates if _pred is locally allocated (true) or not. |
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[100] | 180 | bool local_pred; |
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[244] | 181 | //Pointer to the map of distances. |
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[100] | 182 | DistMap *_dist; |
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[244] | 183 | //Indicates if _dist is locally allocated (true) or not. |
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[100] | 184 | bool local_dist; |
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[244] | 185 | //Pointer to the map of reached status of the nodes. |
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[100] | 186 | ReachedMap *_reached; |
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[244] | 187 | //Indicates if _reached is locally allocated (true) or not. |
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[100] | 188 | bool local_reached; |
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[244] | 189 | //Pointer to the map of processed status of the nodes. |
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[100] | 190 | ProcessedMap *_processed; |
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[244] | 191 | //Indicates if _processed is locally allocated (true) or not. |
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[100] | 192 | bool local_processed; |
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| 193 | |
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| 194 | std::vector<typename Digraph::OutArcIt> _stack; |
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| 195 | int _stack_head; |
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| 196 | |
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[280] | 197 | //Creates the maps if necessary. |
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[209] | 198 | void create_maps() |
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[100] | 199 | { |
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| 200 | if(!_pred) { |
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[209] | 201 | local_pred = true; |
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| 202 | _pred = Traits::createPredMap(*G); |
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[100] | 203 | } |
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| 204 | if(!_dist) { |
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[209] | 205 | local_dist = true; |
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| 206 | _dist = Traits::createDistMap(*G); |
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[100] | 207 | } |
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| 208 | if(!_reached) { |
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[209] | 209 | local_reached = true; |
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| 210 | _reached = Traits::createReachedMap(*G); |
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[100] | 211 | } |
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| 212 | if(!_processed) { |
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[209] | 213 | local_processed = true; |
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| 214 | _processed = Traits::createProcessedMap(*G); |
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[100] | 215 | } |
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| 216 | } |
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| 217 | |
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| 218 | protected: |
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| 219 | |
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| 220 | Dfs() {} |
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[209] | 221 | |
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[100] | 222 | public: |
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| 223 | |
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| 224 | typedef Dfs Create; |
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| 225 | |
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| 226 | ///\name Named template parameters |
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| 227 | |
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| 228 | ///@{ |
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| 229 | |
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| 230 | template <class T> |
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[257] | 231 | struct SetPredMapTraits : public Traits { |
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[100] | 232 | typedef T PredMap; |
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[244] | 233 | static PredMap *createPredMap(const Digraph &) |
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[100] | 234 | { |
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[209] | 235 | throw UninitializedParameter(); |
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[100] | 236 | } |
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| 237 | }; |
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| 238 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 239 | ///\ref PredMap type. |
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[100] | 240 | /// |
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[244] | 241 | ///\ref named-templ-param "Named parameter" for setting |
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| 242 | ///\ref PredMap type. |
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[100] | 243 | template <class T> |
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[257] | 244 | struct SetPredMap : public Dfs<Digraph, SetPredMapTraits<T> > { |
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| 245 | typedef Dfs<Digraph, SetPredMapTraits<T> > Create; |
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[100] | 246 | }; |
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[209] | 247 | |
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[100] | 248 | template <class T> |
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[257] | 249 | struct SetDistMapTraits : public Traits { |
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[100] | 250 | typedef T DistMap; |
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[209] | 251 | static DistMap *createDistMap(const Digraph &) |
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[100] | 252 | { |
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[209] | 253 | throw UninitializedParameter(); |
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[100] | 254 | } |
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| 255 | }; |
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| 256 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 257 | ///\ref DistMap type. |
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[100] | 258 | /// |
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[244] | 259 | ///\ref named-templ-param "Named parameter" for setting |
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| 260 | ///\ref DistMap type. |
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[100] | 261 | template <class T> |
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[257] | 262 | struct SetDistMap : public Dfs< Digraph, SetDistMapTraits<T> > { |
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| 263 | typedef Dfs<Digraph, SetDistMapTraits<T> > Create; |
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[100] | 264 | }; |
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[209] | 265 | |
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[100] | 266 | template <class T> |
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[257] | 267 | struct SetReachedMapTraits : public Traits { |
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[100] | 268 | typedef T ReachedMap; |
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[209] | 269 | static ReachedMap *createReachedMap(const Digraph &) |
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[100] | 270 | { |
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[209] | 271 | throw UninitializedParameter(); |
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[100] | 272 | } |
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| 273 | }; |
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| 274 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 275 | ///\ref ReachedMap type. |
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[100] | 276 | /// |
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[244] | 277 | ///\ref named-templ-param "Named parameter" for setting |
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| 278 | ///\ref ReachedMap type. |
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[100] | 279 | template <class T> |
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[257] | 280 | struct SetReachedMap : public Dfs< Digraph, SetReachedMapTraits<T> > { |
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| 281 | typedef Dfs< Digraph, SetReachedMapTraits<T> > Create; |
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[100] | 282 | }; |
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| 283 | |
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| 284 | template <class T> |
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[257] | 285 | struct SetProcessedMapTraits : public Traits { |
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[100] | 286 | typedef T ProcessedMap; |
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[209] | 287 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 288 | { |
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[209] | 289 | throw UninitializedParameter(); |
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[100] | 290 | } |
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| 291 | }; |
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| 292 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 293 | ///\ref ProcessedMap type. |
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[100] | 294 | /// |
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[244] | 295 | ///\ref named-templ-param "Named parameter" for setting |
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| 296 | ///\ref ProcessedMap type. |
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[100] | 297 | template <class T> |
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[257] | 298 | struct SetProcessedMap : public Dfs< Digraph, SetProcessedMapTraits<T> > { |
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| 299 | typedef Dfs< Digraph, SetProcessedMapTraits<T> > Create; |
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[100] | 300 | }; |
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[209] | 301 | |
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[257] | 302 | struct SetStandardProcessedMapTraits : public Traits { |
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[100] | 303 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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[244] | 304 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 305 | { |
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[244] | 306 | return new ProcessedMap(g); |
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[100] | 307 | } |
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| 308 | }; |
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[244] | 309 | ///\brief \ref named-templ-param "Named parameter" for setting |
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| 310 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 311 | /// |
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[244] | 312 | ///\ref named-templ-param "Named parameter" for setting |
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| 313 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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| 314 | ///If you don't set it explicitly, it will be automatically allocated. |
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[257] | 315 | struct SetStandardProcessedMap : |
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| 316 | public Dfs< Digraph, SetStandardProcessedMapTraits > { |
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| 317 | typedef Dfs< Digraph, SetStandardProcessedMapTraits > Create; |
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[100] | 318 | }; |
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[209] | 319 | |
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[100] | 320 | ///@} |
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| 321 | |
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[209] | 322 | public: |
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| 323 | |
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[100] | 324 | ///Constructor. |
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[209] | 325 | |
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[244] | 326 | ///Constructor. |
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| 327 | ///\param g The digraph the algorithm runs on. |
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| 328 | Dfs(const Digraph &g) : |
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| 329 | G(&g), |
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[100] | 330 | _pred(NULL), local_pred(false), |
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| 331 | _dist(NULL), local_dist(false), |
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| 332 | _reached(NULL), local_reached(false), |
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| 333 | _processed(NULL), local_processed(false) |
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| 334 | { } |
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[209] | 335 | |
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[100] | 336 | ///Destructor. |
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[209] | 337 | ~Dfs() |
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[100] | 338 | { |
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| 339 | if(local_pred) delete _pred; |
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| 340 | if(local_dist) delete _dist; |
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| 341 | if(local_reached) delete _reached; |
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| 342 | if(local_processed) delete _processed; |
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| 343 | } |
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| 344 | |
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[244] | 345 | ///Sets the map that stores the predecessor arcs. |
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[100] | 346 | |
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[244] | 347 | ///Sets the map that stores the predecessor arcs. |
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[100] | 348 | ///If you don't use this function before calling \ref run(), |
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[244] | 349 | ///it will allocate one. The destructor deallocates this |
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[100] | 350 | ///automatically allocated map, of course. |
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| 351 | ///\return <tt> (*this) </tt> |
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[209] | 352 | Dfs &predMap(PredMap &m) |
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[100] | 353 | { |
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| 354 | if(local_pred) { |
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[209] | 355 | delete _pred; |
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| 356 | local_pred=false; |
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[100] | 357 | } |
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| 358 | _pred = &m; |
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| 359 | return *this; |
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| 360 | } |
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| 361 | |
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[244] | 362 | ///Sets the map that indicates which nodes are reached. |
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[100] | 363 | |
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[244] | 364 | ///Sets the map that indicates which nodes are reached. |
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[100] | 365 | ///If you don't use this function before calling \ref run(), |
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[244] | 366 | ///it will allocate one. The destructor deallocates this |
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| 367 | ///automatically allocated map, of course. |
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| 368 | ///\return <tt> (*this) </tt> |
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| 369 | Dfs &reachedMap(ReachedMap &m) |
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| 370 | { |
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| 371 | if(local_reached) { |
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| 372 | delete _reached; |
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| 373 | local_reached=false; |
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| 374 | } |
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| 375 | _reached = &m; |
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| 376 | return *this; |
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| 377 | } |
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| 378 | |
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| 379 | ///Sets the map that indicates which nodes are processed. |
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| 380 | |
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| 381 | ///Sets the map that indicates which nodes are processed. |
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| 382 | ///If you don't use this function before calling \ref run(), |
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| 383 | ///it will allocate one. The destructor deallocates this |
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| 384 | ///automatically allocated map, of course. |
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| 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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| 400 | ///If you don't use this function before calling \ref run(), |
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| 401 | ///it will allocate one. The destructor deallocates this |
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[100] | 402 | ///automatically allocated map, of course. |
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| 403 | ///\return <tt> (*this) </tt> |
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[209] | 404 | Dfs &distMap(DistMap &m) |
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[100] | 405 | { |
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| 406 | if(local_dist) { |
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[209] | 407 | delete _dist; |
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| 408 | local_dist=false; |
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[100] | 409 | } |
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| 410 | _dist = &m; |
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| 411 | return *this; |
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| 412 | } |
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| 413 | |
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[244] | 414 | public: |
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[100] | 415 | |
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| 416 | ///\name Execution control |
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| 417 | ///The simplest way to execute the algorithm is to use |
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[244] | 418 | ///one of the member functions called \ref lemon::Dfs::run() "run()". |
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[100] | 419 | ///\n |
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[244] | 420 | ///If you need more control on the execution, first you must call |
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| 421 | ///\ref lemon::Dfs::init() "init()", then you can add a source node |
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| 422 | ///with \ref lemon::Dfs::addSource() "addSource()". |
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| 423 | ///Finally \ref lemon::Dfs::start() "start()" will perform the |
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| 424 | ///actual path computation. |
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[100] | 425 | |
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| 426 | ///@{ |
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| 427 | |
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| 428 | ///Initializes the internal data structures. |
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| 429 | |
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| 430 | ///Initializes the internal data structures. |
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| 431 | /// |
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| 432 | void init() |
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| 433 | { |
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| 434 | create_maps(); |
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| 435 | _stack.resize(countNodes(*G)); |
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| 436 | _stack_head=-1; |
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| 437 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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[209] | 438 | _pred->set(u,INVALID); |
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| 439 | _reached->set(u,false); |
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| 440 | _processed->set(u,false); |
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[100] | 441 | } |
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| 442 | } |
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[209] | 443 | |
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[100] | 444 | ///Adds a new source node. |
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| 445 | |
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| 446 | ///Adds a new source node to the set of nodes to be processed. |
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| 447 | /// |
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[244] | 448 | ///\pre The stack must be empty. (Otherwise the algorithm gives |
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| 449 | ///false results.) |
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| 450 | /// |
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| 451 | ///\warning Distances will be wrong (or at least strange) in case of |
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| 452 | ///multiple sources. |
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[100] | 453 | void addSource(Node s) |
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| 454 | { |
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[244] | 455 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
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[100] | 456 | if(!(*_reached)[s]) |
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[209] | 457 | { |
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| 458 | _reached->set(s,true); |
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| 459 | _pred->set(s,INVALID); |
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| 460 | OutArcIt e(*G,s); |
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| 461 | if(e!=INVALID) { |
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| 462 | _stack[++_stack_head]=e; |
---|
| 463 | _dist->set(s,_stack_head); |
---|
| 464 | } |
---|
| 465 | else { |
---|
| 466 | _processed->set(s,true); |
---|
| 467 | _dist->set(s,0); |
---|
| 468 | } |
---|
| 469 | } |
---|
[100] | 470 | } |
---|
[209] | 471 | |
---|
[100] | 472 | ///Processes the next arc. |
---|
| 473 | |
---|
| 474 | ///Processes the next arc. |
---|
| 475 | /// |
---|
| 476 | ///\return The processed arc. |
---|
| 477 | /// |
---|
[244] | 478 | ///\pre The stack must not be empty. |
---|
[100] | 479 | Arc processNextArc() |
---|
[209] | 480 | { |
---|
[100] | 481 | Node m; |
---|
| 482 | Arc e=_stack[_stack_head]; |
---|
| 483 | if(!(*_reached)[m=G->target(e)]) { |
---|
[209] | 484 | _pred->set(m,e); |
---|
| 485 | _reached->set(m,true); |
---|
| 486 | ++_stack_head; |
---|
| 487 | _stack[_stack_head] = OutArcIt(*G, m); |
---|
| 488 | _dist->set(m,_stack_head); |
---|
[100] | 489 | } |
---|
| 490 | else { |
---|
[209] | 491 | m=G->source(e); |
---|
| 492 | ++_stack[_stack_head]; |
---|
[100] | 493 | } |
---|
| 494 | while(_stack_head>=0 && _stack[_stack_head]==INVALID) { |
---|
[209] | 495 | _processed->set(m,true); |
---|
| 496 | --_stack_head; |
---|
| 497 | if(_stack_head>=0) { |
---|
| 498 | m=G->source(_stack[_stack_head]); |
---|
| 499 | ++_stack[_stack_head]; |
---|
| 500 | } |
---|
[100] | 501 | } |
---|
| 502 | return e; |
---|
| 503 | } |
---|
[244] | 504 | |
---|
[100] | 505 | ///Next arc to be processed. |
---|
| 506 | |
---|
| 507 | ///Next arc to be processed. |
---|
| 508 | /// |
---|
[244] | 509 | ///\return The next arc to be processed or \c INVALID if the stack |
---|
| 510 | ///is empty. |
---|
| 511 | OutArcIt nextArc() const |
---|
[209] | 512 | { |
---|
[100] | 513 | return _stack_head>=0?_stack[_stack_head]:INVALID; |
---|
| 514 | } |
---|
| 515 | |
---|
| 516 | ///\brief Returns \c false if there are nodes |
---|
[244] | 517 | ///to be processed. |
---|
[100] | 518 | /// |
---|
| 519 | ///Returns \c false if there are nodes |
---|
[244] | 520 | ///to be processed in the queue (stack). |
---|
| 521 | bool emptyQueue() const { return _stack_head<0; } |
---|
| 522 | |
---|
[100] | 523 | ///Returns the number of the nodes to be processed. |
---|
[209] | 524 | |
---|
[244] | 525 | ///Returns the number of the nodes to be processed in the queue (stack). |
---|
| 526 | int queueSize() const { return _stack_head+1; } |
---|
[209] | 527 | |
---|
[100] | 528 | ///Executes the algorithm. |
---|
| 529 | |
---|
| 530 | ///Executes the algorithm. |
---|
| 531 | /// |
---|
[244] | 532 | ///This method runs the %DFS algorithm from the root node |
---|
| 533 | ///in order to compute the DFS path to each node. |
---|
[100] | 534 | /// |
---|
[244] | 535 | /// The algorithm computes |
---|
| 536 | ///- the %DFS tree, |
---|
| 537 | ///- the distance of each node from the root in the %DFS tree. |
---|
[100] | 538 | /// |
---|
[244] | 539 | ///\pre init() must be called and a root node should be |
---|
| 540 | ///added with addSource() before using this function. |
---|
| 541 | /// |
---|
| 542 | ///\note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
| 543 | ///\code |
---|
| 544 | /// while ( !d.emptyQueue() ) { |
---|
| 545 | /// d.processNextArc(); |
---|
| 546 | /// } |
---|
| 547 | ///\endcode |
---|
[100] | 548 | void start() |
---|
| 549 | { |
---|
| 550 | while ( !emptyQueue() ) processNextArc(); |
---|
| 551 | } |
---|
[209] | 552 | |
---|
[244] | 553 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 554 | |
---|
[244] | 555 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 556 | /// |
---|
[244] | 557 | ///This method runs the %DFS algorithm from the root node |
---|
| 558 | ///in order to compute the DFS path to \c dest. |
---|
[100] | 559 | /// |
---|
[244] | 560 | ///The algorithm computes |
---|
| 561 | ///- the %DFS path to \c dest, |
---|
| 562 | ///- the distance of \c dest from the root in the %DFS tree. |
---|
[100] | 563 | /// |
---|
[244] | 564 | ///\pre init() must be called and a root node should be |
---|
| 565 | ///added with addSource() before using this function. |
---|
[100] | 566 | void start(Node dest) |
---|
| 567 | { |
---|
[209] | 568 | while ( !emptyQueue() && G->target(_stack[_stack_head])!=dest ) |
---|
| 569 | processNextArc(); |
---|
[100] | 570 | } |
---|
[209] | 571 | |
---|
[100] | 572 | ///Executes the algorithm until a condition is met. |
---|
| 573 | |
---|
| 574 | ///Executes the algorithm until a condition is met. |
---|
| 575 | /// |
---|
[244] | 576 | ///This method runs the %DFS algorithm from the root node |
---|
| 577 | ///until an arc \c a with <tt>am[a]</tt> true is found. |
---|
[100] | 578 | /// |
---|
[244] | 579 | ///\param am A \c bool (or convertible) arc map. The algorithm |
---|
| 580 | ///will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
---|
[100] | 581 | /// |
---|
[244] | 582 | ///\return The reached arc \c a with <tt>am[a]</tt> true or |
---|
[100] | 583 | ///\c INVALID if no such arc was found. |
---|
| 584 | /// |
---|
[244] | 585 | ///\pre init() must be called and a root node should be |
---|
| 586 | ///added with addSource() before using this function. |
---|
| 587 | /// |
---|
| 588 | ///\warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
---|
[100] | 589 | ///not a node map. |
---|
[244] | 590 | template<class ArcBoolMap> |
---|
| 591 | Arc start(const ArcBoolMap &am) |
---|
[100] | 592 | { |
---|
[244] | 593 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
---|
[100] | 594 | processNextArc(); |
---|
| 595 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
| 596 | } |
---|
| 597 | |
---|
[244] | 598 | ///Runs the algorithm from the given node. |
---|
[209] | 599 | |
---|
[244] | 600 | ///This method runs the %DFS algorithm from node \c s |
---|
| 601 | ///in order to compute the DFS path to each node. |
---|
[100] | 602 | /// |
---|
[244] | 603 | ///The algorithm computes |
---|
| 604 | ///- the %DFS tree, |
---|
| 605 | ///- the distance of each node from the root in the %DFS tree. |
---|
| 606 | /// |
---|
| 607 | ///\note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 608 | ///\code |
---|
| 609 | /// d.init(); |
---|
[244] | 610 | /// d.addSource(s); |
---|
| 611 | /// d.start(); |
---|
| 612 | ///\endcode |
---|
| 613 | void run(Node s) { |
---|
| 614 | init(); |
---|
| 615 | addSource(s); |
---|
| 616 | start(); |
---|
| 617 | } |
---|
| 618 | |
---|
| 619 | ///Finds the %DFS path between \c s and \c t. |
---|
| 620 | |
---|
| 621 | ///This method runs the %DFS algorithm from node \c s |
---|
| 622 | ///in order to compute the DFS path to \c t. |
---|
| 623 | /// |
---|
| 624 | ///\return The length of the <tt>s</tt>--<tt>t</tt> DFS path, |
---|
| 625 | ///if \c t is reachable form \c s, \c 0 otherwise. |
---|
| 626 | /// |
---|
| 627 | ///\note Apart from the return value, <tt>d.run(s,t)</tt> is |
---|
| 628 | ///just a shortcut of the following code. |
---|
| 629 | ///\code |
---|
| 630 | /// d.init(); |
---|
| 631 | /// d.addSource(s); |
---|
| 632 | /// d.start(t); |
---|
| 633 | ///\endcode |
---|
| 634 | int run(Node s,Node t) { |
---|
| 635 | init(); |
---|
| 636 | addSource(s); |
---|
| 637 | start(t); |
---|
| 638 | return reached(t)?_stack_head+1:0; |
---|
| 639 | } |
---|
| 640 | |
---|
| 641 | ///Runs the algorithm to visit all nodes in the digraph. |
---|
| 642 | |
---|
| 643 | ///This method runs the %DFS algorithm in order to compute the |
---|
| 644 | ///%DFS path to each node. |
---|
| 645 | /// |
---|
| 646 | ///The algorithm computes |
---|
| 647 | ///- the %DFS tree, |
---|
| 648 | ///- the distance of each node from the root in the %DFS tree. |
---|
| 649 | /// |
---|
| 650 | ///\note <tt>d.run()</tt> is just a shortcut of the following code. |
---|
| 651 | ///\code |
---|
| 652 | /// d.init(); |
---|
| 653 | /// for (NodeIt n(digraph); n != INVALID; ++n) { |
---|
| 654 | /// if (!d.reached(n)) { |
---|
| 655 | /// d.addSource(n); |
---|
[100] | 656 | /// d.start(); |
---|
| 657 | /// } |
---|
| 658 | /// } |
---|
| 659 | ///\endcode |
---|
| 660 | void run() { |
---|
| 661 | init(); |
---|
| 662 | for (NodeIt it(*G); it != INVALID; ++it) { |
---|
| 663 | if (!reached(it)) { |
---|
| 664 | addSource(it); |
---|
| 665 | start(); |
---|
| 666 | } |
---|
| 667 | } |
---|
| 668 | } |
---|
| 669 | |
---|
| 670 | ///@} |
---|
| 671 | |
---|
| 672 | ///\name Query Functions |
---|
| 673 | ///The result of the %DFS algorithm can be obtained using these |
---|
| 674 | ///functions.\n |
---|
[244] | 675 | ///Either \ref lemon::Dfs::run() "run()" or \ref lemon::Dfs::start() |
---|
| 676 | ///"start()" must be called before using them. |
---|
[209] | 677 | |
---|
[100] | 678 | ///@{ |
---|
| 679 | |
---|
[244] | 680 | ///The DFS path to a node. |
---|
[100] | 681 | |
---|
[244] | 682 | ///Returns the DFS path to a node. |
---|
| 683 | /// |
---|
| 684 | ///\warning \c t should be reachable from the root. |
---|
| 685 | /// |
---|
| 686 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 687 | ///using this function. |
---|
| 688 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
[209] | 689 | |
---|
[244] | 690 | ///The distance of a node from the root. |
---|
[100] | 691 | |
---|
[244] | 692 | ///Returns the distance of a node from the root. |
---|
| 693 | /// |
---|
| 694 | ///\warning If node \c v is not reachable from the root, then |
---|
| 695 | ///the return value of this function is undefined. |
---|
| 696 | /// |
---|
| 697 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 698 | ///using this function. |
---|
[100] | 699 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 700 | |
---|
[244] | 701 | ///Returns the 'previous arc' of the %DFS tree for a node. |
---|
[100] | 702 | |
---|
[244] | 703 | ///This function returns the 'previous arc' of the %DFS tree for the |
---|
| 704 | ///node \c v, i.e. it returns the last arc of a %DFS path from the |
---|
| 705 | ///root to \c v. It is \c INVALID |
---|
| 706 | ///if \c v is not reachable from the root(s) or if \c v is a root. |
---|
| 707 | /// |
---|
| 708 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
[100] | 709 | ///\ref predNode(). |
---|
[244] | 710 | /// |
---|
[100] | 711 | ///\pre Either \ref run() or \ref start() must be called before using |
---|
| 712 | ///this function. |
---|
| 713 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 714 | |
---|
| 715 | ///Returns the 'previous node' of the %DFS tree. |
---|
| 716 | |
---|
[244] | 717 | ///This function returns the 'previous node' of the %DFS |
---|
| 718 | ///tree for the node \c v, i.e. it returns the last but one node |
---|
| 719 | ///from a %DFS path from the root to \c v. It is \c INVALID |
---|
| 720 | ///if \c v is not reachable from the root(s) or if \c v is a root. |
---|
| 721 | /// |
---|
| 722 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
| 723 | ///\ref predArc(). |
---|
| 724 | /// |
---|
[100] | 725 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 726 | ///using this function. |
---|
| 727 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
[209] | 728 | G->source((*_pred)[v]); } |
---|
| 729 | |
---|
[244] | 730 | ///\brief Returns a const reference to the node map that stores the |
---|
| 731 | ///distances of the nodes. |
---|
| 732 | /// |
---|
| 733 | ///Returns a const reference to the node map that stores the |
---|
| 734 | ///distances of the nodes calculated by the algorithm. |
---|
| 735 | /// |
---|
| 736 | ///\pre Either \ref run() or \ref init() |
---|
| 737 | ///must be called before using this function. |
---|
[100] | 738 | const DistMap &distMap() const { return *_dist;} |
---|
[209] | 739 | |
---|
[244] | 740 | ///\brief Returns a const reference to the node map that stores the |
---|
| 741 | ///predecessor arcs. |
---|
| 742 | /// |
---|
| 743 | ///Returns a const reference to the node map that stores the predecessor |
---|
| 744 | ///arcs, which form the DFS tree. |
---|
| 745 | /// |
---|
[100] | 746 | ///\pre Either \ref run() or \ref init() |
---|
| 747 | ///must be called before using this function. |
---|
| 748 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 749 | |
---|
[244] | 750 | ///Checks if a node is reachable from the root(s). |
---|
[100] | 751 | |
---|
| 752 | ///Returns \c true if \c v is reachable from the root(s). |
---|
| 753 | ///\pre Either \ref run() or \ref start() |
---|
| 754 | ///must be called before using this function. |
---|
[244] | 755 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[209] | 756 | |
---|
[100] | 757 | ///@} |
---|
| 758 | }; |
---|
| 759 | |
---|
[244] | 760 | ///Default traits class of dfs() function. |
---|
[100] | 761 | |
---|
[244] | 762 | ///Default traits class of dfs() function. |
---|
[157] | 763 | ///\tparam GR Digraph type. |
---|
[100] | 764 | template<class GR> |
---|
| 765 | struct DfsWizardDefaultTraits |
---|
| 766 | { |
---|
[244] | 767 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 768 | typedef GR Digraph; |
---|
[244] | 769 | |
---|
| 770 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 771 | ///arcs of the %DFS paths. |
---|
[209] | 772 | /// |
---|
[244] | 773 | ///The type of the map that stores the predecessor |
---|
[100] | 774 | ///arcs of the %DFS paths. |
---|
| 775 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 776 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
---|
[244] | 777 | ///Instantiates a \ref PredMap. |
---|
[209] | 778 | |
---|
| 779 | ///This function instantiates a \ref PredMap. |
---|
[244] | 780 | ///\param g is the digraph, to which we would like to define the |
---|
| 781 | ///\ref PredMap. |
---|
| 782 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 783 | { |
---|
[278] | 784 | return new PredMap(g); |
---|
[100] | 785 | } |
---|
| 786 | |
---|
| 787 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 788 | |
---|
[100] | 789 | ///The type of the map that indicates which nodes are processed. |
---|
| 790 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 791 | ///By default it is a NullMap. |
---|
[100] | 792 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[244] | 793 | ///Instantiates a \ref ProcessedMap. |
---|
[209] | 794 | |
---|
| 795 | ///This function instantiates a \ref ProcessedMap. |
---|
[100] | 796 | ///\param g is the digraph, to which |
---|
[244] | 797 | ///we would like to define the \ref ProcessedMap. |
---|
[100] | 798 | #ifdef DOXYGEN |
---|
[244] | 799 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 800 | #else |
---|
[244] | 801 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 802 | #endif |
---|
| 803 | { |
---|
| 804 | return new ProcessedMap(); |
---|
| 805 | } |
---|
[244] | 806 | |
---|
[100] | 807 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 808 | |
---|
[100] | 809 | ///The type of the map that indicates which nodes are reached. |
---|
[244] | 810 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 811 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[244] | 812 | ///Instantiates a \ref ReachedMap. |
---|
[209] | 813 | |
---|
| 814 | ///This function instantiates a \ref ReachedMap. |
---|
[244] | 815 | ///\param g is the digraph, to which |
---|
[100] | 816 | ///we would like to define the \ref ReachedMap. |
---|
[244] | 817 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 818 | { |
---|
[244] | 819 | return new ReachedMap(g); |
---|
[100] | 820 | } |
---|
[209] | 821 | |
---|
[244] | 822 | ///The type of the map that stores the distances of the nodes. |
---|
| 823 | |
---|
| 824 | ///The type of the map that stores the distances of the nodes. |
---|
[100] | 825 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 826 | typedef typename Digraph::template NodeMap<int> DistMap; |
---|
[244] | 827 | ///Instantiates a \ref DistMap. |
---|
[209] | 828 | |
---|
| 829 | ///This function instantiates a \ref DistMap. |
---|
[210] | 830 | ///\param g is the digraph, to which we would like to define |
---|
| 831 | ///the \ref DistMap |
---|
[244] | 832 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 833 | { |
---|
[278] | 834 | return new DistMap(g); |
---|
[100] | 835 | } |
---|
[278] | 836 | |
---|
| 837 | ///The type of the DFS paths. |
---|
| 838 | |
---|
| 839 | ///The type of the DFS paths. |
---|
| 840 | ///It must meet the \ref concepts::Path "Path" concept. |
---|
| 841 | typedef lemon::Path<Digraph> Path; |
---|
[100] | 842 | }; |
---|
[209] | 843 | |
---|
[244] | 844 | /// Default traits class used by \ref DfsWizard |
---|
[100] | 845 | |
---|
| 846 | /// To make it easier to use Dfs algorithm |
---|
[244] | 847 | /// we have created a wizard class. |
---|
[100] | 848 | /// This \ref DfsWizard class needs default traits, |
---|
[244] | 849 | /// as well as the \ref Dfs class. |
---|
[100] | 850 | /// The \ref DfsWizardBase is a class to be the default traits of the |
---|
| 851 | /// \ref DfsWizard class. |
---|
| 852 | template<class GR> |
---|
| 853 | class DfsWizardBase : public DfsWizardDefaultTraits<GR> |
---|
| 854 | { |
---|
| 855 | |
---|
| 856 | typedef DfsWizardDefaultTraits<GR> Base; |
---|
| 857 | protected: |
---|
[244] | 858 | //The type of the nodes in the digraph. |
---|
[100] | 859 | typedef typename Base::Digraph::Node Node; |
---|
| 860 | |
---|
[244] | 861 | //Pointer to the digraph the algorithm runs on. |
---|
[100] | 862 | void *_g; |
---|
[244] | 863 | //Pointer to the map of reached nodes. |
---|
[100] | 864 | void *_reached; |
---|
[244] | 865 | //Pointer to the map of processed nodes. |
---|
[100] | 866 | void *_processed; |
---|
[244] | 867 | //Pointer to the map of predecessors arcs. |
---|
[100] | 868 | void *_pred; |
---|
[244] | 869 | //Pointer to the map of distances. |
---|
[100] | 870 | void *_dist; |
---|
[278] | 871 | //Pointer to the DFS path to the target node. |
---|
| 872 | void *_path; |
---|
| 873 | //Pointer to the distance of the target node. |
---|
| 874 | int *_di; |
---|
[209] | 875 | |
---|
[100] | 876 | public: |
---|
| 877 | /// Constructor. |
---|
[209] | 878 | |
---|
[100] | 879 | /// This constructor does not require parameters, therefore it initiates |
---|
[278] | 880 | /// all of the attributes to \c 0. |
---|
[100] | 881 | DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[278] | 882 | _dist(0), _path(0), _di(0) {} |
---|
[100] | 883 | |
---|
| 884 | /// Constructor. |
---|
[209] | 885 | |
---|
[278] | 886 | /// This constructor requires one parameter, |
---|
| 887 | /// others are initiated to \c 0. |
---|
[244] | 888 | /// \param g The digraph the algorithm runs on. |
---|
[278] | 889 | DfsWizardBase(const GR &g) : |
---|
[209] | 890 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
---|
[278] | 891 | _reached(0), _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
---|
[100] | 892 | |
---|
| 893 | }; |
---|
[209] | 894 | |
---|
[278] | 895 | /// Auxiliary class for the function-type interface of DFS algorithm. |
---|
[100] | 896 | |
---|
[278] | 897 | /// This auxiliary class is created to implement the |
---|
| 898 | /// \ref dfs() "function-type interface" of \ref Dfs algorithm. |
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| 899 | /// It does not have own \ref run() method, it uses the functions |
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| 900 | /// and features of the plain \ref Dfs. |
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[100] | 901 | /// |
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[278] | 902 | /// This class should only be used through the \ref dfs() function, |
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| 903 | /// which makes it easier to use the algorithm. |
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[100] | 904 | template<class TR> |
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| 905 | class DfsWizard : public TR |
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| 906 | { |
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| 907 | typedef TR Base; |
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| 908 | |
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[244] | 909 | ///The type of the digraph the algorithm runs on. |
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[100] | 910 | typedef typename TR::Digraph Digraph; |
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[244] | 911 | |
---|
[100] | 912 | typedef typename Digraph::Node Node; |
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| 913 | typedef typename Digraph::NodeIt NodeIt; |
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| 914 | typedef typename Digraph::Arc Arc; |
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| 915 | typedef typename Digraph::OutArcIt OutArcIt; |
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[209] | 916 | |
---|
[244] | 917 | ///\brief The type of the map that stores the predecessor |
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[278] | 918 | ///arcs of the DFS paths. |
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[244] | 919 | typedef typename TR::PredMap PredMap; |
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| 920 | ///\brief The type of the map that stores the distances of the nodes. |
---|
| 921 | typedef typename TR::DistMap DistMap; |
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| 922 | ///\brief The type of the map that indicates which nodes are reached. |
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[100] | 923 | typedef typename TR::ReachedMap ReachedMap; |
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[244] | 924 | ///\brief The type of the map that indicates which nodes are processed. |
---|
[100] | 925 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
[278] | 926 | ///The type of the DFS paths |
---|
| 927 | typedef typename TR::Path Path; |
---|
[100] | 928 | |
---|
| 929 | public: |
---|
[244] | 930 | |
---|
[100] | 931 | /// Constructor. |
---|
| 932 | DfsWizard() : TR() {} |
---|
| 933 | |
---|
| 934 | /// Constructor that requires parameters. |
---|
| 935 | |
---|
| 936 | /// Constructor that requires parameters. |
---|
| 937 | /// These parameters will be the default values for the traits class. |
---|
[278] | 938 | /// \param g The digraph the algorithm runs on. |
---|
| 939 | DfsWizard(const Digraph &g) : |
---|
| 940 | TR(g) {} |
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[100] | 941 | |
---|
| 942 | ///Copy constructor |
---|
| 943 | DfsWizard(const TR &b) : TR(b) {} |
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| 944 | |
---|
| 945 | ~DfsWizard() {} |
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| 946 | |
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[278] | 947 | ///Runs DFS algorithm from the given source node. |
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[209] | 948 | |
---|
[278] | 949 | ///This method runs DFS algorithm from node \c s |
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| 950 | ///in order to compute the DFS path to each node. |
---|
| 951 | void run(Node s) |
---|
| 952 | { |
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| 953 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 954 | if (Base::_pred) |
---|
| 955 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
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| 956 | if (Base::_dist) |
---|
| 957 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 958 | if (Base::_reached) |
---|
| 959 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 960 | if (Base::_processed) |
---|
| 961 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
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| 962 | if (s!=INVALID) |
---|
| 963 | alg.run(s); |
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| 964 | else |
---|
| 965 | alg.run(); |
---|
| 966 | } |
---|
| 967 | |
---|
| 968 | ///Finds the DFS path between \c s and \c t. |
---|
| 969 | |
---|
| 970 | ///This method runs DFS algorithm from node \c s |
---|
| 971 | ///in order to compute the DFS path to node \c t |
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| 972 | ///(it stops searching when \c t is processed). |
---|
| 973 | /// |
---|
| 974 | ///\return \c true if \c t is reachable form \c s. |
---|
| 975 | bool run(Node s, Node t) |
---|
| 976 | { |
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| 977 | if (s==INVALID || t==INVALID) throw UninitializedParameter(); |
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| 978 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 979 | if (Base::_pred) |
---|
| 980 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
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| 981 | if (Base::_dist) |
---|
| 982 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
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| 983 | if (Base::_reached) |
---|
| 984 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
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| 985 | if (Base::_processed) |
---|
| 986 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 987 | alg.run(s,t); |
---|
| 988 | if (Base::_path) |
---|
| 989 | *reinterpret_cast<Path*>(Base::_path) = alg.path(t); |
---|
| 990 | if (Base::_di) |
---|
| 991 | *Base::_di = alg.dist(t); |
---|
| 992 | return alg.reached(t); |
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| 993 | } |
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| 994 | |
---|
| 995 | ///Runs DFS algorithm to visit all nodes in the digraph. |
---|
| 996 | |
---|
| 997 | ///This method runs DFS algorithm in order to compute |
---|
| 998 | ///the DFS path to each node. |
---|
[100] | 999 | void run() |
---|
| 1000 | { |
---|
[278] | 1001 | run(INVALID); |
---|
[244] | 1002 | } |
---|
| 1003 | |
---|
[100] | 1004 | template<class T> |
---|
[257] | 1005 | struct SetPredMapBase : public Base { |
---|
[100] | 1006 | typedef T PredMap; |
---|
| 1007 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
[257] | 1008 | SetPredMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1009 | }; |
---|
[278] | 1010 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1011 | ///for setting \ref PredMap object. |
---|
[100] | 1012 | /// |
---|
[278] | 1013 | ///\ref named-func-param "Named parameter" |
---|
[244] | 1014 | ///for setting \ref PredMap object. |
---|
[100] | 1015 | template<class T> |
---|
[257] | 1016 | DfsWizard<SetPredMapBase<T> > predMap(const T &t) |
---|
[100] | 1017 | { |
---|
| 1018 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1019 | return DfsWizard<SetPredMapBase<T> >(*this); |
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[100] | 1020 | } |
---|
[209] | 1021 | |
---|
[100] | 1022 | template<class T> |
---|
[257] | 1023 | struct SetReachedMapBase : public Base { |
---|
[100] | 1024 | typedef T ReachedMap; |
---|
| 1025 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
[257] | 1026 | SetReachedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1027 | }; |
---|
[278] | 1028 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1029 | ///for setting \ref ReachedMap object. |
---|
[100] | 1030 | /// |
---|
[278] | 1031 | /// \ref named-func-param "Named parameter" |
---|
[244] | 1032 | ///for setting \ref ReachedMap object. |
---|
[100] | 1033 | template<class T> |
---|
[257] | 1034 | DfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
---|
[100] | 1035 | { |
---|
[158] | 1036 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1037 | return DfsWizard<SetReachedMapBase<T> >(*this); |
---|
[100] | 1038 | } |
---|
[209] | 1039 | |
---|
[100] | 1040 | template<class T> |
---|
[278] | 1041 | struct SetDistMapBase : public Base { |
---|
| 1042 | typedef T DistMap; |
---|
| 1043 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
| 1044 | SetDistMapBase(const TR &b) : TR(b) {} |
---|
| 1045 | }; |
---|
| 1046 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1047 | ///for setting \ref DistMap object. |
---|
| 1048 | /// |
---|
| 1049 | /// \ref named-func-param "Named parameter" |
---|
| 1050 | ///for setting \ref DistMap object. |
---|
| 1051 | template<class T> |
---|
| 1052 | DfsWizard<SetDistMapBase<T> > distMap(const T &t) |
---|
| 1053 | { |
---|
| 1054 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1055 | return DfsWizard<SetDistMapBase<T> >(*this); |
---|
| 1056 | } |
---|
| 1057 | |
---|
| 1058 | template<class T> |
---|
[257] | 1059 | struct SetProcessedMapBase : public Base { |
---|
[100] | 1060 | typedef T ProcessedMap; |
---|
| 1061 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
[257] | 1062 | SetProcessedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1063 | }; |
---|
[278] | 1064 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1065 | ///for setting \ref ProcessedMap object. |
---|
[100] | 1066 | /// |
---|
[278] | 1067 | /// \ref named-func-param "Named parameter" |
---|
[244] | 1068 | ///for setting \ref ProcessedMap object. |
---|
[100] | 1069 | template<class T> |
---|
[257] | 1070 | DfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
---|
[100] | 1071 | { |
---|
[158] | 1072 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1073 | return DfsWizard<SetProcessedMapBase<T> >(*this); |
---|
[100] | 1074 | } |
---|
[209] | 1075 | |
---|
[100] | 1076 | template<class T> |
---|
[278] | 1077 | struct SetPathBase : public Base { |
---|
| 1078 | typedef T Path; |
---|
| 1079 | SetPathBase(const TR &b) : TR(b) {} |
---|
[100] | 1080 | }; |
---|
[278] | 1081 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1082 | ///for getting the DFS path to the target node. |
---|
[100] | 1083 | /// |
---|
[278] | 1084 | ///\ref named-func-param "Named parameter" |
---|
| 1085 | ///for getting the DFS path to the target node. |
---|
[100] | 1086 | template<class T> |
---|
[278] | 1087 | DfsWizard<SetPathBase<T> > path(const T &t) |
---|
[100] | 1088 | { |
---|
[278] | 1089 | Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1090 | return DfsWizard<SetPathBase<T> >(*this); |
---|
| 1091 | } |
---|
| 1092 | |
---|
| 1093 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1094 | ///for getting the distance of the target node. |
---|
| 1095 | /// |
---|
| 1096 | ///\ref named-func-param "Named parameter" |
---|
| 1097 | ///for getting the distance of the target node. |
---|
| 1098 | DfsWizard dist(const int &d) |
---|
| 1099 | { |
---|
| 1100 | Base::_di=const_cast<int*>(&d); |
---|
| 1101 | return *this; |
---|
[100] | 1102 | } |
---|
[209] | 1103 | |
---|
[100] | 1104 | }; |
---|
[209] | 1105 | |
---|
[278] | 1106 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1107 | |
---|
| 1108 | ///\ingroup search |
---|
[278] | 1109 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1110 | /// |
---|
[278] | 1111 | ///This function also has several \ref named-func-param "named parameters", |
---|
[100] | 1112 | ///they are declared as the members of class \ref DfsWizard. |
---|
[278] | 1113 | ///The following examples show how to use these parameters. |
---|
[100] | 1114 | ///\code |
---|
[278] | 1115 | /// // Compute the DFS tree |
---|
| 1116 | /// dfs(g).predMap(preds).distMap(dists).run(s); |
---|
| 1117 | /// |
---|
| 1118 | /// // Compute the DFS path from s to t |
---|
| 1119 | /// bool reached = dfs(g).path(p).dist(d).run(s,t); |
---|
[100] | 1120 | ///\endcode |
---|
[278] | 1121 | |
---|
[100] | 1122 | ///\warning Don't forget to put the \ref DfsWizard::run() "run()" |
---|
| 1123 | ///to the end of the parameter list. |
---|
| 1124 | ///\sa DfsWizard |
---|
| 1125 | ///\sa Dfs |
---|
| 1126 | template<class GR> |
---|
| 1127 | DfsWizard<DfsWizardBase<GR> > |
---|
[278] | 1128 | dfs(const GR &digraph) |
---|
[100] | 1129 | { |
---|
[278] | 1130 | return DfsWizard<DfsWizardBase<GR> >(digraph); |
---|
[100] | 1131 | } |
---|
| 1132 | |
---|
| 1133 | #ifdef DOXYGEN |
---|
[244] | 1134 | /// \brief Visitor class for DFS. |
---|
[209] | 1135 | /// |
---|
[244] | 1136 | /// This class defines the interface of the DfsVisit events, and |
---|
| 1137 | /// it could be the base of a real visitor class. |
---|
[100] | 1138 | template <typename _Digraph> |
---|
| 1139 | struct DfsVisitor { |
---|
| 1140 | typedef _Digraph Digraph; |
---|
| 1141 | typedef typename Digraph::Arc Arc; |
---|
| 1142 | typedef typename Digraph::Node Node; |
---|
[244] | 1143 | /// \brief Called for the source node of the DFS. |
---|
[209] | 1144 | /// |
---|
[244] | 1145 | /// This function is called for the source node of the DFS. |
---|
| 1146 | void start(const Node& node) {} |
---|
| 1147 | /// \brief Called when the source node is leaved. |
---|
| 1148 | /// |
---|
| 1149 | /// This function is called when the source node is leaved. |
---|
| 1150 | void stop(const Node& node) {} |
---|
| 1151 | /// \brief Called when a node is reached first time. |
---|
| 1152 | /// |
---|
| 1153 | /// This function is called when a node is reached first time. |
---|
| 1154 | void reach(const Node& node) {} |
---|
| 1155 | /// \brief Called when an arc reaches a new node. |
---|
| 1156 | /// |
---|
| 1157 | /// This function is called when the DFS finds an arc whose target node |
---|
| 1158 | /// is not reached yet. |
---|
[100] | 1159 | void discover(const Arc& arc) {} |
---|
[244] | 1160 | /// \brief Called when an arc is examined but its target node is |
---|
[100] | 1161 | /// already discovered. |
---|
[209] | 1162 | /// |
---|
[244] | 1163 | /// This function is called when an arc is examined but its target node is |
---|
[100] | 1164 | /// already discovered. |
---|
| 1165 | void examine(const Arc& arc) {} |
---|
[244] | 1166 | /// \brief Called when the DFS steps back from a node. |
---|
[209] | 1167 | /// |
---|
[244] | 1168 | /// This function is called when the DFS steps back from a node. |
---|
| 1169 | void leave(const Node& node) {} |
---|
| 1170 | /// \brief Called when the DFS steps back on an arc. |
---|
[209] | 1171 | /// |
---|
[244] | 1172 | /// This function is called when the DFS steps back on an arc. |
---|
| 1173 | void backtrack(const Arc& arc) {} |
---|
[100] | 1174 | }; |
---|
| 1175 | #else |
---|
| 1176 | template <typename _Digraph> |
---|
| 1177 | struct DfsVisitor { |
---|
| 1178 | typedef _Digraph Digraph; |
---|
| 1179 | typedef typename Digraph::Arc Arc; |
---|
| 1180 | typedef typename Digraph::Node Node; |
---|
| 1181 | void start(const Node&) {} |
---|
| 1182 | void stop(const Node&) {} |
---|
[244] | 1183 | void reach(const Node&) {} |
---|
| 1184 | void discover(const Arc&) {} |
---|
| 1185 | void examine(const Arc&) {} |
---|
| 1186 | void leave(const Node&) {} |
---|
| 1187 | void backtrack(const Arc&) {} |
---|
[100] | 1188 | |
---|
| 1189 | template <typename _Visitor> |
---|
| 1190 | struct Constraints { |
---|
| 1191 | void constraints() { |
---|
[209] | 1192 | Arc arc; |
---|
| 1193 | Node node; |
---|
| 1194 | visitor.start(node); |
---|
| 1195 | visitor.stop(arc); |
---|
[244] | 1196 | visitor.reach(node); |
---|
| 1197 | visitor.discover(arc); |
---|
| 1198 | visitor.examine(arc); |
---|
| 1199 | visitor.leave(node); |
---|
| 1200 | visitor.backtrack(arc); |
---|
[100] | 1201 | } |
---|
| 1202 | _Visitor& visitor; |
---|
| 1203 | }; |
---|
| 1204 | }; |
---|
| 1205 | #endif |
---|
| 1206 | |
---|
| 1207 | /// \brief Default traits class of DfsVisit class. |
---|
| 1208 | /// |
---|
| 1209 | /// Default traits class of DfsVisit class. |
---|
[244] | 1210 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[100] | 1211 | template<class _Digraph> |
---|
| 1212 | struct DfsVisitDefaultTraits { |
---|
| 1213 | |
---|
[244] | 1214 | /// \brief The type of the digraph the algorithm runs on. |
---|
[100] | 1215 | typedef _Digraph Digraph; |
---|
| 1216 | |
---|
| 1217 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1218 | /// |
---|
[100] | 1219 | /// The type of the map that indicates which nodes are reached. |
---|
[244] | 1220 | /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 1221 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1222 | |
---|
[244] | 1223 | /// \brief Instantiates a \ref ReachedMap. |
---|
[100] | 1224 | /// |
---|
[209] | 1225 | /// This function instantiates a \ref ReachedMap. |
---|
[100] | 1226 | /// \param digraph is the digraph, to which |
---|
| 1227 | /// we would like to define the \ref ReachedMap. |
---|
| 1228 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1229 | return new ReachedMap(digraph); |
---|
| 1230 | } |
---|
| 1231 | |
---|
| 1232 | }; |
---|
[209] | 1233 | |
---|
[100] | 1234 | /// \ingroup search |
---|
[244] | 1235 | /// |
---|
| 1236 | /// \brief %DFS algorithm class with visitor interface. |
---|
| 1237 | /// |
---|
[100] | 1238 | /// This class provides an efficient implementation of the %DFS algorithm |
---|
| 1239 | /// with visitor interface. |
---|
| 1240 | /// |
---|
| 1241 | /// The %DfsVisit class provides an alternative interface to the Dfs |
---|
| 1242 | /// class. It works with callback mechanism, the DfsVisit object calls |
---|
[244] | 1243 | /// the member functions of the \c Visitor class on every DFS event. |
---|
[100] | 1244 | /// |
---|
[252] | 1245 | /// This interface of the DFS algorithm should be used in special cases |
---|
| 1246 | /// when extra actions have to be performed in connection with certain |
---|
| 1247 | /// events of the DFS algorithm. Otherwise consider to use Dfs or dfs() |
---|
| 1248 | /// instead. |
---|
| 1249 | /// |
---|
[244] | 1250 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[210] | 1251 | /// The default value is |
---|
[244] | 1252 | /// \ref ListDigraph. The value of _Digraph is not used directly by |
---|
| 1253 | /// \ref DfsVisit, it is only passed to \ref DfsVisitDefaultTraits. |
---|
| 1254 | /// \tparam _Visitor The Visitor type that is used by the algorithm. |
---|
| 1255 | /// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty visitor, which |
---|
| 1256 | /// does not observe the DFS events. If you want to observe the DFS |
---|
| 1257 | /// events, you should implement your own visitor class. |
---|
[209] | 1258 | /// \tparam _Traits Traits class to set various data types used by the |
---|
[100] | 1259 | /// algorithm. The default traits class is |
---|
| 1260 | /// \ref DfsVisitDefaultTraits "DfsVisitDefaultTraits<_Digraph>". |
---|
| 1261 | /// See \ref DfsVisitDefaultTraits for the documentation of |
---|
[244] | 1262 | /// a DFS visit traits class. |
---|
[100] | 1263 | #ifdef DOXYGEN |
---|
| 1264 | template <typename _Digraph, typename _Visitor, typename _Traits> |
---|
| 1265 | #else |
---|
| 1266 | template <typename _Digraph = ListDigraph, |
---|
[209] | 1267 | typename _Visitor = DfsVisitor<_Digraph>, |
---|
| 1268 | typename _Traits = DfsDefaultTraits<_Digraph> > |
---|
[100] | 1269 | #endif |
---|
| 1270 | class DfsVisit { |
---|
| 1271 | public: |
---|
[209] | 1272 | |
---|
[100] | 1273 | /// \brief \ref Exception for uninitialized parameters. |
---|
| 1274 | /// |
---|
| 1275 | /// This error represents problems in the initialization |
---|
[244] | 1276 | /// of the parameters of the algorithm. |
---|
[100] | 1277 | class UninitializedParameter : public lemon::UninitializedParameter { |
---|
| 1278 | public: |
---|
[209] | 1279 | virtual const char* what() const throw() |
---|
[100] | 1280 | { |
---|
[209] | 1281 | return "lemon::DfsVisit::UninitializedParameter"; |
---|
[100] | 1282 | } |
---|
| 1283 | }; |
---|
| 1284 | |
---|
[244] | 1285 | ///The traits class. |
---|
[100] | 1286 | typedef _Traits Traits; |
---|
| 1287 | |
---|
[244] | 1288 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 1289 | typedef typename Traits::Digraph Digraph; |
---|
| 1290 | |
---|
[244] | 1291 | ///The visitor type used by the algorithm. |
---|
[100] | 1292 | typedef _Visitor Visitor; |
---|
| 1293 | |
---|
[244] | 1294 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 1295 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1296 | |
---|
| 1297 | private: |
---|
| 1298 | |
---|
| 1299 | typedef typename Digraph::Node Node; |
---|
| 1300 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1301 | typedef typename Digraph::Arc Arc; |
---|
| 1302 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1303 | |
---|
[244] | 1304 | //Pointer to the underlying digraph. |
---|
[100] | 1305 | const Digraph *_digraph; |
---|
[244] | 1306 | //Pointer to the visitor object. |
---|
[100] | 1307 | Visitor *_visitor; |
---|
[244] | 1308 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 1309 | ReachedMap *_reached; |
---|
[244] | 1310 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 1311 | bool local_reached; |
---|
| 1312 | |
---|
| 1313 | std::vector<typename Digraph::Arc> _stack; |
---|
| 1314 | int _stack_head; |
---|
| 1315 | |
---|
[280] | 1316 | //Creates the maps if necessary. |
---|
[100] | 1317 | void create_maps() { |
---|
| 1318 | if(!_reached) { |
---|
[209] | 1319 | local_reached = true; |
---|
| 1320 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1321 | } |
---|
| 1322 | } |
---|
| 1323 | |
---|
| 1324 | protected: |
---|
| 1325 | |
---|
| 1326 | DfsVisit() {} |
---|
[209] | 1327 | |
---|
[100] | 1328 | public: |
---|
| 1329 | |
---|
| 1330 | typedef DfsVisit Create; |
---|
| 1331 | |
---|
| 1332 | /// \name Named template parameters |
---|
| 1333 | |
---|
| 1334 | ///@{ |
---|
| 1335 | template <class T> |
---|
[257] | 1336 | struct SetReachedMapTraits : public Traits { |
---|
[100] | 1337 | typedef T ReachedMap; |
---|
| 1338 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
[209] | 1339 | throw UninitializedParameter(); |
---|
[100] | 1340 | } |
---|
| 1341 | }; |
---|
[209] | 1342 | /// \brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 1343 | /// ReachedMap type. |
---|
[100] | 1344 | /// |
---|
[244] | 1345 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
---|
[100] | 1346 | template <class T> |
---|
[257] | 1347 | struct SetReachedMap : public DfsVisit< Digraph, Visitor, |
---|
| 1348 | SetReachedMapTraits<T> > { |
---|
| 1349 | typedef DfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
---|
[100] | 1350 | }; |
---|
| 1351 | ///@} |
---|
| 1352 | |
---|
[209] | 1353 | public: |
---|
| 1354 | |
---|
[100] | 1355 | /// \brief Constructor. |
---|
| 1356 | /// |
---|
| 1357 | /// Constructor. |
---|
| 1358 | /// |
---|
[244] | 1359 | /// \param digraph The digraph the algorithm runs on. |
---|
| 1360 | /// \param visitor The visitor object of the algorithm. |
---|
[209] | 1361 | DfsVisit(const Digraph& digraph, Visitor& visitor) |
---|
[100] | 1362 | : _digraph(&digraph), _visitor(&visitor), |
---|
[209] | 1363 | _reached(0), local_reached(false) {} |
---|
| 1364 | |
---|
[100] | 1365 | /// \brief Destructor. |
---|
| 1366 | ~DfsVisit() { |
---|
| 1367 | if(local_reached) delete _reached; |
---|
| 1368 | } |
---|
| 1369 | |
---|
[244] | 1370 | /// \brief Sets the map that indicates which nodes are reached. |
---|
[100] | 1371 | /// |
---|
[244] | 1372 | /// Sets the map that indicates which nodes are reached. |
---|
[100] | 1373 | /// If you don't use this function before calling \ref run(), |
---|
[244] | 1374 | /// it will allocate one. The destructor deallocates this |
---|
[100] | 1375 | /// automatically allocated map, of course. |
---|
| 1376 | /// \return <tt> (*this) </tt> |
---|
| 1377 | DfsVisit &reachedMap(ReachedMap &m) { |
---|
| 1378 | if(local_reached) { |
---|
[209] | 1379 | delete _reached; |
---|
| 1380 | local_reached=false; |
---|
[100] | 1381 | } |
---|
| 1382 | _reached = &m; |
---|
| 1383 | return *this; |
---|
| 1384 | } |
---|
| 1385 | |
---|
| 1386 | public: |
---|
[244] | 1387 | |
---|
[100] | 1388 | /// \name Execution control |
---|
| 1389 | /// The simplest way to execute the algorithm is to use |
---|
[244] | 1390 | /// one of the member functions called \ref lemon::DfsVisit::run() |
---|
| 1391 | /// "run()". |
---|
[100] | 1392 | /// \n |
---|
[244] | 1393 | /// If you need more control on the execution, first you must call |
---|
| 1394 | /// \ref lemon::DfsVisit::init() "init()", then you can add several |
---|
| 1395 | /// source nodes with \ref lemon::DfsVisit::addSource() "addSource()". |
---|
| 1396 | /// Finally \ref lemon::DfsVisit::start() "start()" will perform the |
---|
| 1397 | /// actual path computation. |
---|
[100] | 1398 | |
---|
| 1399 | /// @{ |
---|
[244] | 1400 | |
---|
[100] | 1401 | /// \brief Initializes the internal data structures. |
---|
| 1402 | /// |
---|
| 1403 | /// Initializes the internal data structures. |
---|
| 1404 | void init() { |
---|
| 1405 | create_maps(); |
---|
| 1406 | _stack.resize(countNodes(*_digraph)); |
---|
| 1407 | _stack_head = -1; |
---|
| 1408 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
---|
[209] | 1409 | _reached->set(u, false); |
---|
[100] | 1410 | } |
---|
| 1411 | } |
---|
[209] | 1412 | |
---|
[244] | 1413 | ///Adds a new source node. |
---|
| 1414 | |
---|
| 1415 | ///Adds a new source node to the set of nodes to be processed. |
---|
[100] | 1416 | /// |
---|
[244] | 1417 | ///\pre The stack must be empty. (Otherwise the algorithm gives |
---|
| 1418 | ///false results.) |
---|
| 1419 | /// |
---|
| 1420 | ///\warning Distances will be wrong (or at least strange) in case of |
---|
| 1421 | ///multiple sources. |
---|
| 1422 | void addSource(Node s) |
---|
| 1423 | { |
---|
| 1424 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
---|
[100] | 1425 | if(!(*_reached)[s]) { |
---|
[209] | 1426 | _reached->set(s,true); |
---|
| 1427 | _visitor->start(s); |
---|
| 1428 | _visitor->reach(s); |
---|
| 1429 | Arc e; |
---|
| 1430 | _digraph->firstOut(e, s); |
---|
| 1431 | if (e != INVALID) { |
---|
| 1432 | _stack[++_stack_head] = e; |
---|
| 1433 | } else { |
---|
| 1434 | _visitor->leave(s); |
---|
| 1435 | } |
---|
| 1436 | } |
---|
[100] | 1437 | } |
---|
[209] | 1438 | |
---|
[100] | 1439 | /// \brief Processes the next arc. |
---|
| 1440 | /// |
---|
| 1441 | /// Processes the next arc. |
---|
| 1442 | /// |
---|
| 1443 | /// \return The processed arc. |
---|
| 1444 | /// |
---|
[244] | 1445 | /// \pre The stack must not be empty. |
---|
[209] | 1446 | Arc processNextArc() { |
---|
[100] | 1447 | Arc e = _stack[_stack_head]; |
---|
| 1448 | Node m = _digraph->target(e); |
---|
| 1449 | if(!(*_reached)[m]) { |
---|
[209] | 1450 | _visitor->discover(e); |
---|
| 1451 | _visitor->reach(m); |
---|
| 1452 | _reached->set(m, true); |
---|
| 1453 | _digraph->firstOut(_stack[++_stack_head], m); |
---|
[100] | 1454 | } else { |
---|
[209] | 1455 | _visitor->examine(e); |
---|
| 1456 | m = _digraph->source(e); |
---|
| 1457 | _digraph->nextOut(_stack[_stack_head]); |
---|
[100] | 1458 | } |
---|
| 1459 | while (_stack_head>=0 && _stack[_stack_head] == INVALID) { |
---|
[209] | 1460 | _visitor->leave(m); |
---|
| 1461 | --_stack_head; |
---|
| 1462 | if (_stack_head >= 0) { |
---|
| 1463 | _visitor->backtrack(_stack[_stack_head]); |
---|
| 1464 | m = _digraph->source(_stack[_stack_head]); |
---|
| 1465 | _digraph->nextOut(_stack[_stack_head]); |
---|
| 1466 | } else { |
---|
| 1467 | _visitor->stop(m); |
---|
| 1468 | } |
---|
[100] | 1469 | } |
---|
| 1470 | return e; |
---|
| 1471 | } |
---|
| 1472 | |
---|
| 1473 | /// \brief Next arc to be processed. |
---|
| 1474 | /// |
---|
| 1475 | /// Next arc to be processed. |
---|
| 1476 | /// |
---|
| 1477 | /// \return The next arc to be processed or INVALID if the stack is |
---|
| 1478 | /// empty. |
---|
[244] | 1479 | Arc nextArc() const { |
---|
[100] | 1480 | return _stack_head >= 0 ? _stack[_stack_head] : INVALID; |
---|
| 1481 | } |
---|
| 1482 | |
---|
| 1483 | /// \brief Returns \c false if there are nodes |
---|
[244] | 1484 | /// to be processed. |
---|
[100] | 1485 | /// |
---|
| 1486 | /// Returns \c false if there are nodes |
---|
[244] | 1487 | /// to be processed in the queue (stack). |
---|
| 1488 | bool emptyQueue() const { return _stack_head < 0; } |
---|
[100] | 1489 | |
---|
| 1490 | /// \brief Returns the number of the nodes to be processed. |
---|
| 1491 | /// |
---|
[244] | 1492 | /// Returns the number of the nodes to be processed in the queue (stack). |
---|
| 1493 | int queueSize() const { return _stack_head + 1; } |
---|
[209] | 1494 | |
---|
[100] | 1495 | /// \brief Executes the algorithm. |
---|
| 1496 | /// |
---|
| 1497 | /// Executes the algorithm. |
---|
| 1498 | /// |
---|
[244] | 1499 | /// This method runs the %DFS algorithm from the root node |
---|
| 1500 | /// in order to compute the %DFS path to each node. |
---|
| 1501 | /// |
---|
| 1502 | /// The algorithm computes |
---|
| 1503 | /// - the %DFS tree, |
---|
| 1504 | /// - the distance of each node from the root in the %DFS tree. |
---|
| 1505 | /// |
---|
| 1506 | /// \pre init() must be called and a root node should be |
---|
| 1507 | /// added with addSource() before using this function. |
---|
| 1508 | /// |
---|
| 1509 | /// \note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
| 1510 | /// \code |
---|
| 1511 | /// while ( !d.emptyQueue() ) { |
---|
| 1512 | /// d.processNextArc(); |
---|
| 1513 | /// } |
---|
| 1514 | /// \endcode |
---|
[100] | 1515 | void start() { |
---|
| 1516 | while ( !emptyQueue() ) processNextArc(); |
---|
| 1517 | } |
---|
[209] | 1518 | |
---|
[244] | 1519 | /// \brief Executes the algorithm until the given target node is reached. |
---|
[100] | 1520 | /// |
---|
[244] | 1521 | /// Executes the algorithm until the given target node is reached. |
---|
[100] | 1522 | /// |
---|
[244] | 1523 | /// This method runs the %DFS algorithm from the root node |
---|
| 1524 | /// in order to compute the DFS path to \c dest. |
---|
| 1525 | /// |
---|
| 1526 | /// The algorithm computes |
---|
| 1527 | /// - the %DFS path to \c dest, |
---|
| 1528 | /// - the distance of \c dest from the root in the %DFS tree. |
---|
| 1529 | /// |
---|
| 1530 | /// \pre init() must be called and a root node should be added |
---|
[100] | 1531 | /// with addSource() before using this function. |
---|
| 1532 | void start(Node dest) { |
---|
[209] | 1533 | while ( !emptyQueue() && _digraph->target(_stack[_stack_head]) != dest ) |
---|
| 1534 | processNextArc(); |
---|
[100] | 1535 | } |
---|
[209] | 1536 | |
---|
[100] | 1537 | /// \brief Executes the algorithm until a condition is met. |
---|
| 1538 | /// |
---|
| 1539 | /// Executes the algorithm until a condition is met. |
---|
| 1540 | /// |
---|
[244] | 1541 | /// This method runs the %DFS algorithm from the root node |
---|
| 1542 | /// until an arc \c a with <tt>am[a]</tt> true is found. |
---|
| 1543 | /// |
---|
| 1544 | /// \param am A \c bool (or convertible) arc map. The algorithm |
---|
| 1545 | /// will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
---|
| 1546 | /// |
---|
| 1547 | /// \return The reached arc \c a with <tt>am[a]</tt> true or |
---|
| 1548 | /// \c INVALID if no such arc was found. |
---|
| 1549 | /// |
---|
| 1550 | /// \pre init() must be called and a root node should be added |
---|
[100] | 1551 | /// with addSource() before using this function. |
---|
| 1552 | /// |
---|
[244] | 1553 | /// \warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
---|
[100] | 1554 | /// not a node map. |
---|
[244] | 1555 | template <typename AM> |
---|
| 1556 | Arc start(const AM &am) { |
---|
| 1557 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
---|
[100] | 1558 | processNextArc(); |
---|
| 1559 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
| 1560 | } |
---|
| 1561 | |
---|
[244] | 1562 | /// \brief Runs the algorithm from the given node. |
---|
[100] | 1563 | /// |
---|
[244] | 1564 | /// This method runs the %DFS algorithm from node \c s. |
---|
| 1565 | /// in order to compute the DFS path to each node. |
---|
| 1566 | /// |
---|
| 1567 | /// The algorithm computes |
---|
| 1568 | /// - the %DFS tree, |
---|
| 1569 | /// - the distance of each node from the root in the %DFS tree. |
---|
| 1570 | /// |
---|
| 1571 | /// \note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1572 | ///\code |
---|
| 1573 | /// d.init(); |
---|
| 1574 | /// d.addSource(s); |
---|
| 1575 | /// d.start(); |
---|
| 1576 | ///\endcode |
---|
| 1577 | void run(Node s) { |
---|
| 1578 | init(); |
---|
| 1579 | addSource(s); |
---|
| 1580 | start(); |
---|
| 1581 | } |
---|
| 1582 | |
---|
[244] | 1583 | /// \brief Finds the %DFS path between \c s and \c t. |
---|
| 1584 | |
---|
| 1585 | /// This method runs the %DFS algorithm from node \c s |
---|
| 1586 | /// in order to compute the DFS path to \c t. |
---|
| 1587 | /// |
---|
| 1588 | /// \return The length of the <tt>s</tt>--<tt>t</tt> DFS path, |
---|
| 1589 | /// if \c t is reachable form \c s, \c 0 otherwise. |
---|
| 1590 | /// |
---|
| 1591 | /// \note Apart from the return value, <tt>d.run(s,t)</tt> is |
---|
| 1592 | /// just a shortcut of the following code. |
---|
| 1593 | ///\code |
---|
| 1594 | /// d.init(); |
---|
| 1595 | /// d.addSource(s); |
---|
| 1596 | /// d.start(t); |
---|
| 1597 | ///\endcode |
---|
| 1598 | int run(Node s,Node t) { |
---|
| 1599 | init(); |
---|
| 1600 | addSource(s); |
---|
| 1601 | start(t); |
---|
| 1602 | return reached(t)?_stack_head+1:0; |
---|
| 1603 | } |
---|
| 1604 | |
---|
| 1605 | /// \brief Runs the algorithm to visit all nodes in the digraph. |
---|
[209] | 1606 | |
---|
[100] | 1607 | /// This method runs the %DFS algorithm in order to |
---|
[244] | 1608 | /// compute the %DFS path to each node. |
---|
[100] | 1609 | /// |
---|
[244] | 1610 | /// The algorithm computes |
---|
| 1611 | /// - the %DFS tree, |
---|
| 1612 | /// - the distance of each node from the root in the %DFS tree. |
---|
| 1613 | /// |
---|
| 1614 | /// \note <tt>d.run()</tt> is just a shortcut of the following code. |
---|
[100] | 1615 | ///\code |
---|
[244] | 1616 | /// d.init(); |
---|
| 1617 | /// for (NodeIt n(digraph); n != INVALID; ++n) { |
---|
| 1618 | /// if (!d.reached(n)) { |
---|
| 1619 | /// d.addSource(n); |
---|
| 1620 | /// d.start(); |
---|
| 1621 | /// } |
---|
| 1622 | /// } |
---|
[100] | 1623 | ///\endcode |
---|
| 1624 | void run() { |
---|
| 1625 | init(); |
---|
| 1626 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
| 1627 | if (!reached(it)) { |
---|
| 1628 | addSource(it); |
---|
| 1629 | start(); |
---|
| 1630 | } |
---|
| 1631 | } |
---|
| 1632 | } |
---|
[244] | 1633 | |
---|
[100] | 1634 | ///@} |
---|
| 1635 | |
---|
| 1636 | /// \name Query Functions |
---|
| 1637 | /// The result of the %DFS algorithm can be obtained using these |
---|
| 1638 | /// functions.\n |
---|
[244] | 1639 | /// Either \ref lemon::DfsVisit::run() "run()" or |
---|
| 1640 | /// \ref lemon::DfsVisit::start() "start()" must be called before |
---|
| 1641 | /// using them. |
---|
[100] | 1642 | ///@{ |
---|
[244] | 1643 | |
---|
| 1644 | /// \brief Checks if a node is reachable from the root(s). |
---|
[100] | 1645 | /// |
---|
| 1646 | /// Returns \c true if \c v is reachable from the root(s). |
---|
| 1647 | /// \pre Either \ref run() or \ref start() |
---|
| 1648 | /// must be called before using this function. |
---|
| 1649 | bool reached(Node v) { return (*_reached)[v]; } |
---|
[244] | 1650 | |
---|
[100] | 1651 | ///@} |
---|
[244] | 1652 | |
---|
[100] | 1653 | }; |
---|
| 1654 | |
---|
| 1655 | } //END OF NAMESPACE LEMON |
---|
| 1656 | |
---|
| 1657 | #endif |
---|