[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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[1270] | 5 | * Copyright (C) 2003-2013 |
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[100] | 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | #ifndef LEMON_DFS_H |
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| 20 | #define LEMON_DFS_H |
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| 21 | |
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| 22 | ///\ingroup search |
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| 23 | ///\file |
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[244] | 24 | ///\brief DFS algorithm. |
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[100] | 25 | |
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| 26 | #include <lemon/list_graph.h> |
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| 27 | #include <lemon/bits/path_dump.h> |
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[220] | 28 | #include <lemon/core.h> |
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[100] | 29 | #include <lemon/error.h> |
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| 30 | #include <lemon/maps.h> |
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[278] | 31 | #include <lemon/path.h> |
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[100] | 32 | |
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| 33 | namespace lemon { |
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| 34 | |
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| 35 | ///Default traits class of Dfs class. |
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| 36 | |
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| 37 | ///Default traits class of Dfs class. |
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[157] | 38 | ///\tparam GR Digraph type. |
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[100] | 39 | template<class GR> |
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| 40 | struct DfsDefaultTraits |
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| 41 | { |
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[244] | 42 | ///The type of the digraph the algorithm runs on. |
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[100] | 43 | typedef GR Digraph; |
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[244] | 44 | |
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| 45 | ///\brief The type of the map that stores the predecessor |
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[100] | 46 | ///arcs of the %DFS paths. |
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[209] | 47 | /// |
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[244] | 48 | ///The type of the map that stores the predecessor |
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[100] | 49 | ///arcs of the %DFS paths. |
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[763] | 50 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[244] | 51 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
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[525] | 52 | ///Instantiates a \c PredMap. |
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[209] | 53 | |
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[525] | 54 | ///This function instantiates a \ref PredMap. |
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[244] | 55 | ///\param g is the digraph, to which we would like to define the |
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[525] | 56 | ///\ref PredMap. |
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[244] | 57 | static PredMap *createPredMap(const Digraph &g) |
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[100] | 58 | { |
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[244] | 59 | return new PredMap(g); |
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[100] | 60 | } |
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| 61 | |
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| 62 | ///The type of the map that indicates which nodes are processed. |
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[209] | 63 | |
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[100] | 64 | ///The type of the map that indicates which nodes are processed. |
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[763] | 65 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[833] | 66 | ///By default, it is a NullMap. |
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[100] | 67 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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[525] | 68 | ///Instantiates a \c ProcessedMap. |
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[209] | 69 | |
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[525] | 70 | ///This function instantiates a \ref ProcessedMap. |
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[100] | 71 | ///\param g is the digraph, to which |
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[525] | 72 | ///we would like to define the \ref ProcessedMap. |
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[100] | 73 | #ifdef DOXYGEN |
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[244] | 74 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 75 | #else |
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[244] | 76 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 77 | #endif |
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| 78 | { |
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| 79 | return new ProcessedMap(); |
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| 80 | } |
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[244] | 81 | |
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[100] | 82 | ///The type of the map that indicates which nodes are reached. |
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[209] | 83 | |
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[100] | 84 | ///The type of the map that indicates which nodes are reached. |
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[956] | 85 | ///It must conform to |
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| 86 | ///the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 87 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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[525] | 88 | ///Instantiates a \c ReachedMap. |
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[209] | 89 | |
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[525] | 90 | ///This function instantiates a \ref ReachedMap. |
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[244] | 91 | ///\param g is the digraph, to which |
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[525] | 92 | ///we would like to define the \ref ReachedMap. |
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[244] | 93 | static ReachedMap *createReachedMap(const Digraph &g) |
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[100] | 94 | { |
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[244] | 95 | return new ReachedMap(g); |
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[100] | 96 | } |
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[209] | 97 | |
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[244] | 98 | ///The type of the map that stores the distances of the nodes. |
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| 99 | |
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| 100 | ///The type of the map that stores the distances of the nodes. |
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[763] | 101 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 102 | typedef typename Digraph::template NodeMap<int> DistMap; |
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[525] | 103 | ///Instantiates a \c DistMap. |
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[209] | 104 | |
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[525] | 105 | ///This function instantiates a \ref DistMap. |
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[244] | 106 | ///\param g is the digraph, to which we would like to define the |
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[525] | 107 | ///\ref DistMap. |
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[244] | 108 | static DistMap *createDistMap(const Digraph &g) |
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[100] | 109 | { |
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[244] | 110 | return new DistMap(g); |
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[100] | 111 | } |
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| 112 | }; |
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[209] | 113 | |
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[100] | 114 | ///%DFS algorithm class. |
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[209] | 115 | |
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[100] | 116 | ///\ingroup search |
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| 117 | ///This class provides an efficient implementation of the %DFS algorithm. |
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| 118 | /// |
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[278] | 119 | ///There is also a \ref dfs() "function-type interface" for the DFS |
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[244] | 120 | ///algorithm, which is convenient in the simplier cases and it can be |
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| 121 | ///used easier. |
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| 122 | /// |
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| 123 | ///\tparam GR The type of the digraph the algorithm runs on. |
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[421] | 124 | ///The default type is \ref ListDigraph. |
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[891] | 125 | ///\tparam TR The traits class that defines various types used by the |
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| 126 | ///algorithm. By default, it is \ref DfsDefaultTraits |
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| 127 | ///"DfsDefaultTraits<GR>". |
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| 128 | ///In most cases, this parameter should not be set directly, |
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| 129 | ///consider to use the named template parameters instead. |
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[100] | 130 | #ifdef DOXYGEN |
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| 131 | template <typename GR, |
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[209] | 132 | typename TR> |
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[100] | 133 | #else |
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| 134 | template <typename GR=ListDigraph, |
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[209] | 135 | typename TR=DfsDefaultTraits<GR> > |
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[100] | 136 | #endif |
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| 137 | class Dfs { |
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| 138 | public: |
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| 139 | |
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[244] | 140 | ///The type of the digraph the algorithm runs on. |
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| 141 | typedef typename TR::Digraph Digraph; |
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| 142 | |
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| 143 | ///\brief The type of the map that stores the predecessor arcs of the |
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| 144 | ///DFS paths. |
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| 145 | typedef typename TR::PredMap PredMap; |
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| 146 | ///The type of the map that stores the distances of the nodes. |
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| 147 | typedef typename TR::DistMap DistMap; |
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| 148 | ///The type of the map that indicates which nodes are reached. |
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| 149 | typedef typename TR::ReachedMap ReachedMap; |
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| 150 | ///The type of the map that indicates which nodes are processed. |
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| 151 | typedef typename TR::ProcessedMap ProcessedMap; |
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| 152 | ///The type of the paths. |
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| 153 | typedef PredMapPath<Digraph, PredMap> Path; |
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| 154 | |
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[1250] | 155 | ///The \ref lemon::DfsDefaultTraits "traits class" of the algorithm. |
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[100] | 156 | typedef TR Traits; |
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[244] | 157 | |
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| 158 | private: |
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| 159 | |
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[100] | 160 | typedef typename Digraph::Node Node; |
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| 161 | typedef typename Digraph::NodeIt NodeIt; |
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| 162 | typedef typename Digraph::Arc Arc; |
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| 163 | typedef typename Digraph::OutArcIt OutArcIt; |
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[209] | 164 | |
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[244] | 165 | //Pointer to the underlying digraph. |
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[100] | 166 | const Digraph *G; |
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[244] | 167 | //Pointer to the map of predecessor arcs. |
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[100] | 168 | PredMap *_pred; |
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[244] | 169 | //Indicates if _pred is locally allocated (true) or not. |
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[100] | 170 | bool local_pred; |
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[244] | 171 | //Pointer to the map of distances. |
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[100] | 172 | DistMap *_dist; |
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[244] | 173 | //Indicates if _dist is locally allocated (true) or not. |
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[100] | 174 | bool local_dist; |
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[244] | 175 | //Pointer to the map of reached status of the nodes. |
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[100] | 176 | ReachedMap *_reached; |
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[244] | 177 | //Indicates if _reached is locally allocated (true) or not. |
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[100] | 178 | bool local_reached; |
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[244] | 179 | //Pointer to the map of processed status of the nodes. |
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[100] | 180 | ProcessedMap *_processed; |
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[244] | 181 | //Indicates if _processed is locally allocated (true) or not. |
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[100] | 182 | bool local_processed; |
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| 183 | |
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[1418] | 184 | std::vector<typename Digraph::Arc> _stack; |
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[100] | 185 | int _stack_head; |
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| 186 | |
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[280] | 187 | //Creates the maps if necessary. |
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[209] | 188 | void create_maps() |
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[100] | 189 | { |
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| 190 | if(!_pred) { |
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[209] | 191 | local_pred = true; |
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| 192 | _pred = Traits::createPredMap(*G); |
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[100] | 193 | } |
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| 194 | if(!_dist) { |
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[209] | 195 | local_dist = true; |
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| 196 | _dist = Traits::createDistMap(*G); |
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[100] | 197 | } |
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| 198 | if(!_reached) { |
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[209] | 199 | local_reached = true; |
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| 200 | _reached = Traits::createReachedMap(*G); |
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[100] | 201 | } |
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| 202 | if(!_processed) { |
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[209] | 203 | local_processed = true; |
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| 204 | _processed = Traits::createProcessedMap(*G); |
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[100] | 205 | } |
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| 206 | } |
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| 207 | |
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| 208 | protected: |
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| 209 | |
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| 210 | Dfs() {} |
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[209] | 211 | |
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[100] | 212 | public: |
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| 213 | |
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| 214 | typedef Dfs Create; |
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| 215 | |
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[631] | 216 | ///\name Named Template Parameters |
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[100] | 217 | |
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| 218 | ///@{ |
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| 219 | |
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| 220 | template <class T> |
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[257] | 221 | struct SetPredMapTraits : public Traits { |
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[100] | 222 | typedef T PredMap; |
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[244] | 223 | static PredMap *createPredMap(const Digraph &) |
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[100] | 224 | { |
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[290] | 225 | LEMON_ASSERT(false, "PredMap is not initialized"); |
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| 226 | return 0; // ignore warnings |
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[100] | 227 | } |
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| 228 | }; |
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| 229 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[525] | 230 | ///\c PredMap type. |
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[100] | 231 | /// |
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[244] | 232 | ///\ref named-templ-param "Named parameter" for setting |
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[525] | 233 | ///\c PredMap type. |
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[763] | 234 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 235 | template <class T> |
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[257] | 236 | struct SetPredMap : public Dfs<Digraph, SetPredMapTraits<T> > { |
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| 237 | typedef Dfs<Digraph, SetPredMapTraits<T> > Create; |
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[100] | 238 | }; |
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[209] | 239 | |
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[100] | 240 | template <class T> |
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[257] | 241 | struct SetDistMapTraits : public Traits { |
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[100] | 242 | typedef T DistMap; |
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[209] | 243 | static DistMap *createDistMap(const Digraph &) |
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[100] | 244 | { |
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[290] | 245 | LEMON_ASSERT(false, "DistMap is not initialized"); |
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| 246 | return 0; // ignore warnings |
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[100] | 247 | } |
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| 248 | }; |
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| 249 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[525] | 250 | ///\c DistMap type. |
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[100] | 251 | /// |
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[244] | 252 | ///\ref named-templ-param "Named parameter" for setting |
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[525] | 253 | ///\c DistMap type. |
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[763] | 254 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 255 | template <class T> |
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[257] | 256 | struct SetDistMap : public Dfs< Digraph, SetDistMapTraits<T> > { |
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| 257 | typedef Dfs<Digraph, SetDistMapTraits<T> > Create; |
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[100] | 258 | }; |
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[209] | 259 | |
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[100] | 260 | template <class T> |
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[257] | 261 | struct SetReachedMapTraits : public Traits { |
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[100] | 262 | typedef T ReachedMap; |
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[209] | 263 | static ReachedMap *createReachedMap(const Digraph &) |
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[100] | 264 | { |
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[290] | 265 | LEMON_ASSERT(false, "ReachedMap is not initialized"); |
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| 266 | return 0; // ignore warnings |
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[100] | 267 | } |
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| 268 | }; |
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| 269 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[525] | 270 | ///\c ReachedMap type. |
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[100] | 271 | /// |
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[244] | 272 | ///\ref named-templ-param "Named parameter" for setting |
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[525] | 273 | ///\c ReachedMap type. |
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[956] | 274 | ///It must conform to |
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| 275 | ///the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 276 | template <class T> |
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[257] | 277 | struct SetReachedMap : public Dfs< Digraph, SetReachedMapTraits<T> > { |
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| 278 | typedef Dfs< Digraph, SetReachedMapTraits<T> > Create; |
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[100] | 279 | }; |
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| 280 | |
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| 281 | template <class T> |
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[257] | 282 | struct SetProcessedMapTraits : public Traits { |
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[100] | 283 | typedef T ProcessedMap; |
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[209] | 284 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 285 | { |
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[290] | 286 | LEMON_ASSERT(false, "ProcessedMap is not initialized"); |
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| 287 | return 0; // ignore warnings |
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[100] | 288 | } |
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| 289 | }; |
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| 290 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[525] | 291 | ///\c ProcessedMap type. |
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[100] | 292 | /// |
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[244] | 293 | ///\ref named-templ-param "Named parameter" for setting |
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[525] | 294 | ///\c ProcessedMap type. |
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[763] | 295 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
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[100] | 296 | template <class T> |
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[257] | 297 | struct SetProcessedMap : public Dfs< Digraph, SetProcessedMapTraits<T> > { |
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| 298 | typedef Dfs< Digraph, SetProcessedMapTraits<T> > Create; |
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[100] | 299 | }; |
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[209] | 300 | |
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[257] | 301 | struct SetStandardProcessedMapTraits : public Traits { |
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[100] | 302 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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[244] | 303 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 304 | { |
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[244] | 305 | return new ProcessedMap(g); |
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[100] | 306 | } |
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| 307 | }; |
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[244] | 308 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[525] | 309 | ///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 310 | /// |
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[244] | 311 | ///\ref named-templ-param "Named parameter" for setting |
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[525] | 312 | ///\c ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[244] | 313 | ///If you don't set it explicitly, it will be automatically allocated. |
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[257] | 314 | struct SetStandardProcessedMap : |
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| 315 | public Dfs< Digraph, SetStandardProcessedMapTraits > { |
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| 316 | typedef Dfs< Digraph, SetStandardProcessedMapTraits > Create; |
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[100] | 317 | }; |
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[209] | 318 | |
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[100] | 319 | ///@} |
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| 320 | |
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[209] | 321 | public: |
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| 322 | |
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[100] | 323 | ///Constructor. |
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[209] | 324 | |
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[244] | 325 | ///Constructor. |
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| 326 | ///\param g The digraph the algorithm runs on. |
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| 327 | Dfs(const Digraph &g) : |
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| 328 | G(&g), |
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[100] | 329 | _pred(NULL), local_pred(false), |
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| 330 | _dist(NULL), local_dist(false), |
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| 331 | _reached(NULL), local_reached(false), |
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| 332 | _processed(NULL), local_processed(false) |
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| 333 | { } |
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[209] | 334 | |
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[100] | 335 | ///Destructor. |
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[209] | 336 | ~Dfs() |
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[100] | 337 | { |
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| 338 | if(local_pred) delete _pred; |
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| 339 | if(local_dist) delete _dist; |
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| 340 | if(local_reached) delete _reached; |
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| 341 | if(local_processed) delete _processed; |
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| 342 | } |
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| 343 | |
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[244] | 344 | ///Sets the map that stores the predecessor arcs. |
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[100] | 345 | |
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[244] | 346 | ///Sets the map that stores the predecessor arcs. |
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[421] | 347 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 348 | ///or \ref init(), an instance will be allocated automatically. |
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| 349 | ///The destructor deallocates this automatically allocated map, |
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| 350 | ///of course. |
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[100] | 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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[421] | 365 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 366 | ///or \ref init(), an instance will be allocated automatically. |
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| 367 | ///The destructor deallocates this automatically allocated map, |
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| 368 | ///of course. |
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[244] | 369 | ///\return <tt> (*this) </tt> |
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| 370 | Dfs &reachedMap(ReachedMap &m) |
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| 371 | { |
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| 372 | if(local_reached) { |
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| 373 | delete _reached; |
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| 374 | local_reached=false; |
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| 375 | } |
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| 376 | _reached = &m; |
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| 377 | return *this; |
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| 378 | } |
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| 379 | |
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| 380 | ///Sets the map that indicates which nodes are processed. |
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| 381 | |
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| 382 | ///Sets the map that indicates which nodes are processed. |
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[421] | 383 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 384 | ///or \ref init(), an instance will be allocated automatically. |
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| 385 | ///The destructor deallocates this automatically allocated map, |
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| 386 | ///of course. |
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[244] | 387 | ///\return <tt> (*this) </tt> |
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| 388 | Dfs &processedMap(ProcessedMap &m) |
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| 389 | { |
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| 390 | if(local_processed) { |
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| 391 | delete _processed; |
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| 392 | local_processed=false; |
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| 393 | } |
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| 394 | _processed = &m; |
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| 395 | return *this; |
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| 396 | } |
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| 397 | |
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| 398 | ///Sets the map that stores the distances of the nodes. |
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| 399 | |
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| 400 | ///Sets the map that stores the distances of the nodes calculated by |
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| 401 | ///the algorithm. |
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[421] | 402 | ///If you don't use this function before calling \ref run(Node) "run()" |
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| 403 | ///or \ref init(), an instance will be allocated automatically. |
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| 404 | ///The destructor deallocates this automatically allocated map, |
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| 405 | ///of course. |
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[100] | 406 | ///\return <tt> (*this) </tt> |
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[209] | 407 | Dfs &distMap(DistMap &m) |
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[100] | 408 | { |
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| 409 | if(local_dist) { |
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[209] | 410 | delete _dist; |
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| 411 | local_dist=false; |
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[100] | 412 | } |
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| 413 | _dist = &m; |
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| 414 | return *this; |
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| 415 | } |
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| 416 | |
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[244] | 417 | public: |
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[100] | 418 | |
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[421] | 419 | ///\name Execution Control |
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| 420 | ///The simplest way to execute the DFS algorithm is to use one of the |
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| 421 | ///member functions called \ref run(Node) "run()".\n |
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[760] | 422 | ///If you need better control on the execution, you have to call |
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| 423 | ///\ref init() first, then you can add a source node with \ref addSource() |
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[421] | 424 | ///and perform the actual computation with \ref start(). |
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| 425 | ///This procedure can be repeated if there are nodes that have not |
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| 426 | ///been reached. |
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[100] | 427 | |
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| 428 | ///@{ |
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| 429 | |
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[421] | 430 | ///\brief Initializes the internal data structures. |
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| 431 | /// |
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[100] | 432 | ///Initializes the internal data structures. |
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| 433 | void init() |
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| 434 | { |
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| 435 | create_maps(); |
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| 436 | _stack.resize(countNodes(*G)); |
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| 437 | _stack_head=-1; |
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| 438 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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[209] | 439 | _pred->set(u,INVALID); |
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| 440 | _reached->set(u,false); |
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| 441 | _processed->set(u,false); |
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[100] | 442 | } |
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| 443 | } |
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[209] | 444 | |
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[100] | 445 | ///Adds a new source node. |
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| 446 | |
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| 447 | ///Adds a new source node to the set of nodes to be processed. |
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| 448 | /// |
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[421] | 449 | ///\pre The stack must be empty. Otherwise the algorithm gives |
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| 450 | ///wrong results. (One of the outgoing arcs of all the source nodes |
---|
| 451 | ///except for the last one will not be visited and distances will |
---|
| 452 | ///also be wrong.) |
---|
[100] | 453 | void addSource(Node s) |
---|
| 454 | { |
---|
[244] | 455 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
---|
[100] | 456 | if(!(*_reached)[s]) |
---|
[209] | 457 | { |
---|
| 458 | _reached->set(s,true); |
---|
| 459 | _pred->set(s,INVALID); |
---|
[1418] | 460 | Arc e; |
---|
| 461 | G->firstOut(e,s); |
---|
[209] | 462 | if(e!=INVALID) { |
---|
| 463 | _stack[++_stack_head]=e; |
---|
| 464 | _dist->set(s,_stack_head); |
---|
| 465 | } |
---|
| 466 | else { |
---|
| 467 | _processed->set(s,true); |
---|
| 468 | _dist->set(s,0); |
---|
| 469 | } |
---|
| 470 | } |
---|
[100] | 471 | } |
---|
[209] | 472 | |
---|
[100] | 473 | ///Processes the next arc. |
---|
| 474 | |
---|
| 475 | ///Processes the next arc. |
---|
| 476 | /// |
---|
| 477 | ///\return The processed arc. |
---|
| 478 | /// |
---|
[244] | 479 | ///\pre The stack must not be empty. |
---|
[100] | 480 | Arc processNextArc() |
---|
[209] | 481 | { |
---|
[100] | 482 | Node m; |
---|
| 483 | Arc e=_stack[_stack_head]; |
---|
| 484 | if(!(*_reached)[m=G->target(e)]) { |
---|
[209] | 485 | _pred->set(m,e); |
---|
| 486 | _reached->set(m,true); |
---|
| 487 | ++_stack_head; |
---|
[1418] | 488 | G->firstOut(_stack[_stack_head],m); |
---|
[209] | 489 | _dist->set(m,_stack_head); |
---|
[100] | 490 | } |
---|
| 491 | else { |
---|
[209] | 492 | m=G->source(e); |
---|
[1418] | 493 | G->nextOut(_stack[_stack_head]); |
---|
[100] | 494 | } |
---|
| 495 | while(_stack_head>=0 && _stack[_stack_head]==INVALID) { |
---|
[209] | 496 | _processed->set(m,true); |
---|
| 497 | --_stack_head; |
---|
| 498 | if(_stack_head>=0) { |
---|
| 499 | m=G->source(_stack[_stack_head]); |
---|
[1418] | 500 | G->nextOut(_stack[_stack_head]); |
---|
[209] | 501 | } |
---|
[100] | 502 | } |
---|
| 503 | return e; |
---|
| 504 | } |
---|
[244] | 505 | |
---|
[100] | 506 | ///Next arc to be processed. |
---|
| 507 | |
---|
| 508 | ///Next arc to be processed. |
---|
| 509 | /// |
---|
[244] | 510 | ///\return The next arc to be processed or \c INVALID if the stack |
---|
| 511 | ///is empty. |
---|
| 512 | OutArcIt nextArc() const |
---|
[209] | 513 | { |
---|
[1418] | 514 | return OutArcIt(*G,_stack_head>=0?_stack[_stack_head]:INVALID); |
---|
[100] | 515 | } |
---|
| 516 | |
---|
[421] | 517 | ///Returns \c false if there are nodes to be processed. |
---|
| 518 | |
---|
| 519 | ///Returns \c false if there are nodes to be processed |
---|
| 520 | ///in the queue (stack). |
---|
[244] | 521 | bool emptyQueue() const { return _stack_head<0; } |
---|
| 522 | |
---|
[100] | 523 | ///Returns the number of the nodes to be processed. |
---|
[209] | 524 | |
---|
[421] | 525 | ///Returns the number of the nodes to be processed |
---|
| 526 | ///in the queue (stack). |
---|
[244] | 527 | int queueSize() const { return _stack_head+1; } |
---|
[209] | 528 | |
---|
[100] | 529 | ///Executes the algorithm. |
---|
| 530 | |
---|
| 531 | ///Executes the algorithm. |
---|
| 532 | /// |
---|
[244] | 533 | ///This method runs the %DFS algorithm from the root node |
---|
| 534 | ///in order to compute the DFS path to each node. |
---|
[100] | 535 | /// |
---|
[244] | 536 | /// The algorithm computes |
---|
| 537 | ///- the %DFS tree, |
---|
| 538 | ///- the distance of each node from the root in the %DFS tree. |
---|
[100] | 539 | /// |
---|
[244] | 540 | ///\pre init() must be called and a root node should be |
---|
| 541 | ///added with addSource() before using this function. |
---|
| 542 | /// |
---|
| 543 | ///\note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
| 544 | ///\code |
---|
| 545 | /// while ( !d.emptyQueue() ) { |
---|
| 546 | /// d.processNextArc(); |
---|
| 547 | /// } |
---|
| 548 | ///\endcode |
---|
[100] | 549 | void start() |
---|
| 550 | { |
---|
| 551 | while ( !emptyQueue() ) processNextArc(); |
---|
| 552 | } |
---|
[209] | 553 | |
---|
[244] | 554 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 555 | |
---|
[244] | 556 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 557 | /// |
---|
[244] | 558 | ///This method runs the %DFS algorithm from the root node |
---|
[286] | 559 | ///in order to compute the DFS path to \c t. |
---|
[100] | 560 | /// |
---|
[244] | 561 | ///The algorithm computes |
---|
[286] | 562 | ///- the %DFS path to \c t, |
---|
| 563 | ///- the distance of \c t from the root in the %DFS tree. |
---|
[100] | 564 | /// |
---|
[244] | 565 | ///\pre init() must be called and a root node should be |
---|
| 566 | ///added with addSource() before using this function. |
---|
[286] | 567 | void start(Node t) |
---|
[100] | 568 | { |
---|
[1007] | 569 | while ( !emptyQueue() && !(*_reached)[t] ) |
---|
[209] | 570 | processNextArc(); |
---|
[100] | 571 | } |
---|
[209] | 572 | |
---|
[100] | 573 | ///Executes the algorithm until a condition is met. |
---|
| 574 | |
---|
| 575 | ///Executes the algorithm until a condition is met. |
---|
| 576 | /// |
---|
[244] | 577 | ///This method runs the %DFS algorithm from the root node |
---|
| 578 | ///until an arc \c a with <tt>am[a]</tt> true is found. |
---|
[100] | 579 | /// |
---|
[244] | 580 | ///\param am A \c bool (or convertible) arc map. The algorithm |
---|
| 581 | ///will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
---|
[100] | 582 | /// |
---|
[244] | 583 | ///\return The reached arc \c a with <tt>am[a]</tt> true or |
---|
[100] | 584 | ///\c INVALID if no such arc was found. |
---|
| 585 | /// |
---|
[244] | 586 | ///\pre init() must be called and a root node should be |
---|
| 587 | ///added with addSource() before using this function. |
---|
| 588 | /// |
---|
| 589 | ///\warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
---|
[100] | 590 | ///not a node map. |
---|
[244] | 591 | template<class ArcBoolMap> |
---|
| 592 | Arc start(const ArcBoolMap &am) |
---|
[100] | 593 | { |
---|
[244] | 594 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
---|
[100] | 595 | processNextArc(); |
---|
| 596 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
| 597 | } |
---|
| 598 | |
---|
[286] | 599 | ///Runs the algorithm from the given source node. |
---|
[209] | 600 | |
---|
[244] | 601 | ///This method runs the %DFS algorithm from node \c s |
---|
| 602 | ///in order to compute the DFS path to each node. |
---|
[100] | 603 | /// |
---|
[244] | 604 | ///The algorithm computes |
---|
| 605 | ///- the %DFS tree, |
---|
| 606 | ///- the distance of each node from the root in the %DFS tree. |
---|
| 607 | /// |
---|
| 608 | ///\note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 609 | ///\code |
---|
| 610 | /// d.init(); |
---|
[244] | 611 | /// d.addSource(s); |
---|
| 612 | /// d.start(); |
---|
| 613 | ///\endcode |
---|
| 614 | void run(Node s) { |
---|
| 615 | init(); |
---|
| 616 | addSource(s); |
---|
| 617 | start(); |
---|
| 618 | } |
---|
| 619 | |
---|
| 620 | ///Finds the %DFS path between \c s and \c t. |
---|
| 621 | |
---|
| 622 | ///This method runs the %DFS algorithm from node \c s |
---|
[286] | 623 | ///in order to compute the DFS path to node \c t |
---|
| 624 | ///(it stops searching when \c t is processed) |
---|
[244] | 625 | /// |
---|
[286] | 626 | ///\return \c true if \c t is reachable form \c s. |
---|
[244] | 627 | /// |
---|
| 628 | ///\note Apart from the return value, <tt>d.run(s,t)</tt> is |
---|
| 629 | ///just a shortcut of the following code. |
---|
| 630 | ///\code |
---|
| 631 | /// d.init(); |
---|
| 632 | /// d.addSource(s); |
---|
| 633 | /// d.start(t); |
---|
| 634 | ///\endcode |
---|
[286] | 635 | bool run(Node s,Node t) { |
---|
[244] | 636 | init(); |
---|
| 637 | addSource(s); |
---|
| 638 | start(t); |
---|
[286] | 639 | return reached(t); |
---|
[244] | 640 | } |
---|
| 641 | |
---|
| 642 | ///Runs the algorithm to visit all nodes in the digraph. |
---|
| 643 | |
---|
[834] | 644 | ///This method runs the %DFS algorithm in order to visit all nodes |
---|
| 645 | ///in the digraph. |
---|
[244] | 646 | /// |
---|
| 647 | ///\note <tt>d.run()</tt> is just a shortcut of the following code. |
---|
| 648 | ///\code |
---|
| 649 | /// d.init(); |
---|
| 650 | /// for (NodeIt n(digraph); n != INVALID; ++n) { |
---|
| 651 | /// if (!d.reached(n)) { |
---|
| 652 | /// d.addSource(n); |
---|
[100] | 653 | /// d.start(); |
---|
| 654 | /// } |
---|
| 655 | /// } |
---|
| 656 | ///\endcode |
---|
| 657 | void run() { |
---|
| 658 | init(); |
---|
| 659 | for (NodeIt it(*G); it != INVALID; ++it) { |
---|
| 660 | if (!reached(it)) { |
---|
| 661 | addSource(it); |
---|
| 662 | start(); |
---|
| 663 | } |
---|
| 664 | } |
---|
| 665 | } |
---|
| 666 | |
---|
| 667 | ///@} |
---|
| 668 | |
---|
| 669 | ///\name Query Functions |
---|
[421] | 670 | ///The results of the DFS algorithm can be obtained using these |
---|
[100] | 671 | ///functions.\n |
---|
[421] | 672 | ///Either \ref run(Node) "run()" or \ref start() should be called |
---|
| 673 | ///before using them. |
---|
[209] | 674 | |
---|
[100] | 675 | ///@{ |
---|
| 676 | |
---|
[763] | 677 | ///The DFS path to the given node. |
---|
[100] | 678 | |
---|
[763] | 679 | ///Returns the DFS path to the given node from the root(s). |
---|
[244] | 680 | /// |
---|
[421] | 681 | ///\warning \c t should be reached from the root(s). |
---|
[244] | 682 | /// |
---|
[421] | 683 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 684 | ///must be called before using this function. |
---|
[244] | 685 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
[209] | 686 | |
---|
[763] | 687 | ///The distance of the given node from the root(s). |
---|
[100] | 688 | |
---|
[763] | 689 | ///Returns the distance of the given node from the root(s). |
---|
[244] | 690 | /// |
---|
[421] | 691 | ///\warning If node \c v is not reached from the root(s), then |
---|
[244] | 692 | ///the return value of this function is undefined. |
---|
| 693 | /// |
---|
[421] | 694 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 695 | ///must be called before using this function. |
---|
[100] | 696 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 697 | |
---|
[763] | 698 | ///Returns the 'previous arc' of the %DFS tree for the given node. |
---|
[100] | 699 | |
---|
[244] | 700 | ///This function returns the 'previous arc' of the %DFS tree for the |
---|
[421] | 701 | ///node \c v, i.e. it returns the last arc of a %DFS path from a |
---|
| 702 | ///root to \c v. It is \c INVALID if \c v is not reached from the |
---|
| 703 | ///root(s) or if \c v is a root. |
---|
[244] | 704 | /// |
---|
| 705 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
[763] | 706 | ///\ref predNode() and \ref predMap(). |
---|
[244] | 707 | /// |
---|
[421] | 708 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 709 | ///must be called before using this function. |
---|
[100] | 710 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 711 | |
---|
[763] | 712 | ///Returns the 'previous node' of the %DFS tree for the given node. |
---|
[100] | 713 | |
---|
[244] | 714 | ///This function returns the 'previous node' of the %DFS |
---|
| 715 | ///tree for the node \c v, i.e. it returns the last but one node |
---|
[763] | 716 | ///of a %DFS path from a root to \c v. It is \c INVALID |
---|
[421] | 717 | ///if \c v is not reached from the root(s) or if \c v is a root. |
---|
[244] | 718 | /// |
---|
| 719 | ///The %DFS tree used here is equal to the %DFS tree used in |
---|
[763] | 720 | ///\ref predArc() and \ref predMap(). |
---|
[244] | 721 | /// |
---|
[421] | 722 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
| 723 | ///must be called before using this function. |
---|
[100] | 724 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
[209] | 725 | G->source((*_pred)[v]); } |
---|
| 726 | |
---|
[244] | 727 | ///\brief Returns a const reference to the node map that stores the |
---|
| 728 | ///distances of the nodes. |
---|
| 729 | /// |
---|
| 730 | ///Returns a const reference to the node map that stores the |
---|
| 731 | ///distances of the nodes calculated by the algorithm. |
---|
| 732 | /// |
---|
[421] | 733 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
[244] | 734 | ///must be called before using this function. |
---|
[100] | 735 | const DistMap &distMap() const { return *_dist;} |
---|
[209] | 736 | |
---|
[244] | 737 | ///\brief Returns a const reference to the node map that stores the |
---|
| 738 | ///predecessor arcs. |
---|
| 739 | /// |
---|
| 740 | ///Returns a const reference to the node map that stores the predecessor |
---|
[763] | 741 | ///arcs, which form the DFS tree (forest). |
---|
[244] | 742 | /// |
---|
[421] | 743 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
[100] | 744 | ///must be called before using this function. |
---|
| 745 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 746 | |
---|
[763] | 747 | ///Checks if the given node. node is reached from the root(s). |
---|
[100] | 748 | |
---|
[421] | 749 | ///Returns \c true if \c v is reached from the root(s). |
---|
| 750 | /// |
---|
| 751 | ///\pre Either \ref run(Node) "run()" or \ref init() |
---|
[100] | 752 | ///must be called before using this function. |
---|
[244] | 753 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[209] | 754 | |
---|
[100] | 755 | ///@} |
---|
| 756 | }; |
---|
| 757 | |
---|
[244] | 758 | ///Default traits class of dfs() function. |
---|
[100] | 759 | |
---|
[244] | 760 | ///Default traits class of dfs() function. |
---|
[157] | 761 | ///\tparam GR Digraph type. |
---|
[100] | 762 | template<class GR> |
---|
| 763 | struct DfsWizardDefaultTraits |
---|
| 764 | { |
---|
[244] | 765 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 766 | typedef GR Digraph; |
---|
[244] | 767 | |
---|
| 768 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 769 | ///arcs of the %DFS paths. |
---|
[209] | 770 | /// |
---|
[244] | 771 | ///The type of the map that stores the predecessor |
---|
[100] | 772 | ///arcs of the %DFS paths. |
---|
[763] | 773 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 774 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
---|
[301] | 775 | ///Instantiates a PredMap. |
---|
[209] | 776 | |
---|
[301] | 777 | ///This function instantiates a PredMap. |
---|
[244] | 778 | ///\param g is the digraph, to which we would like to define the |
---|
[301] | 779 | ///PredMap. |
---|
[244] | 780 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 781 | { |
---|
[278] | 782 | return new PredMap(g); |
---|
[100] | 783 | } |
---|
| 784 | |
---|
| 785 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 786 | |
---|
[100] | 787 | ///The type of the map that indicates which nodes are processed. |
---|
[763] | 788 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
---|
[833] | 789 | ///By default, it is a NullMap. |
---|
[100] | 790 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[301] | 791 | ///Instantiates a ProcessedMap. |
---|
[209] | 792 | |
---|
[301] | 793 | ///This function instantiates a ProcessedMap. |
---|
[100] | 794 | ///\param g is the digraph, to which |
---|
[301] | 795 | ///we would like to define the ProcessedMap. |
---|
[100] | 796 | #ifdef DOXYGEN |
---|
[244] | 797 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 798 | #else |
---|
[244] | 799 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 800 | #endif |
---|
| 801 | { |
---|
| 802 | return new ProcessedMap(); |
---|
| 803 | } |
---|
[244] | 804 | |
---|
[100] | 805 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 806 | |
---|
[100] | 807 | ///The type of the map that indicates which nodes are reached. |
---|
[956] | 808 | ///It must conform to |
---|
| 809 | ///the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 810 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[301] | 811 | ///Instantiates a ReachedMap. |
---|
[209] | 812 | |
---|
[301] | 813 | ///This function instantiates a ReachedMap. |
---|
[244] | 814 | ///\param g is the digraph, to which |
---|
[301] | 815 | ///we would like to define the ReachedMap. |
---|
[244] | 816 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 817 | { |
---|
[244] | 818 | return new ReachedMap(g); |
---|
[100] | 819 | } |
---|
[209] | 820 | |
---|
[244] | 821 | ///The type of the map that stores the distances of the nodes. |
---|
| 822 | |
---|
| 823 | ///The type of the map that stores the distances of the nodes. |
---|
[763] | 824 | ///It must conform to the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 825 | typedef typename Digraph::template NodeMap<int> DistMap; |
---|
[301] | 826 | ///Instantiates a DistMap. |
---|
[209] | 827 | |
---|
[301] | 828 | ///This function instantiates a DistMap. |
---|
[210] | 829 | ///\param g is the digraph, to which we would like to define |
---|
[301] | 830 | ///the DistMap |
---|
[244] | 831 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 832 | { |
---|
[278] | 833 | return new DistMap(g); |
---|
[100] | 834 | } |
---|
[278] | 835 | |
---|
| 836 | ///The type of the DFS paths. |
---|
| 837 | |
---|
| 838 | ///The type of the DFS paths. |
---|
[763] | 839 | ///It must conform to the \ref concepts::Path "Path" concept. |
---|
[278] | 840 | typedef lemon::Path<Digraph> Path; |
---|
[100] | 841 | }; |
---|
[209] | 842 | |
---|
[313] | 843 | /// Default traits class used by DfsWizard |
---|
[100] | 844 | |
---|
[763] | 845 | /// Default traits class used by DfsWizard. |
---|
| 846 | /// \tparam GR The type of the digraph. |
---|
[100] | 847 | template<class GR> |
---|
| 848 | class DfsWizardBase : public DfsWizardDefaultTraits<GR> |
---|
| 849 | { |
---|
| 850 | |
---|
| 851 | typedef DfsWizardDefaultTraits<GR> Base; |
---|
| 852 | protected: |
---|
[244] | 853 | //The type of the nodes in the digraph. |
---|
[100] | 854 | typedef typename Base::Digraph::Node Node; |
---|
| 855 | |
---|
[244] | 856 | //Pointer to the digraph the algorithm runs on. |
---|
[100] | 857 | void *_g; |
---|
[244] | 858 | //Pointer to the map of reached nodes. |
---|
[100] | 859 | void *_reached; |
---|
[244] | 860 | //Pointer to the map of processed nodes. |
---|
[100] | 861 | void *_processed; |
---|
[244] | 862 | //Pointer to the map of predecessors arcs. |
---|
[100] | 863 | void *_pred; |
---|
[244] | 864 | //Pointer to the map of distances. |
---|
[100] | 865 | void *_dist; |
---|
[278] | 866 | //Pointer to the DFS path to the target node. |
---|
| 867 | void *_path; |
---|
| 868 | //Pointer to the distance of the target node. |
---|
| 869 | int *_di; |
---|
[209] | 870 | |
---|
[100] | 871 | public: |
---|
| 872 | /// Constructor. |
---|
[209] | 873 | |
---|
[763] | 874 | /// This constructor does not require parameters, it initiates |
---|
[278] | 875 | /// all of the attributes to \c 0. |
---|
[100] | 876 | DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[278] | 877 | _dist(0), _path(0), _di(0) {} |
---|
[100] | 878 | |
---|
| 879 | /// Constructor. |
---|
[209] | 880 | |
---|
[278] | 881 | /// This constructor requires one parameter, |
---|
| 882 | /// others are initiated to \c 0. |
---|
[244] | 883 | /// \param g The digraph the algorithm runs on. |
---|
[278] | 884 | DfsWizardBase(const GR &g) : |
---|
[209] | 885 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
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[278] | 886 | _reached(0), _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
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[100] | 887 | |
---|
| 888 | }; |
---|
[209] | 889 | |
---|
[278] | 890 | /// Auxiliary class for the function-type interface of DFS algorithm. |
---|
[100] | 891 | |
---|
[278] | 892 | /// This auxiliary class is created to implement the |
---|
| 893 | /// \ref dfs() "function-type interface" of \ref Dfs algorithm. |
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[421] | 894 | /// It does not have own \ref run(Node) "run()" method, it uses the |
---|
| 895 | /// functions and features of the plain \ref Dfs. |
---|
[100] | 896 | /// |
---|
[278] | 897 | /// This class should only be used through the \ref dfs() function, |
---|
| 898 | /// which makes it easier to use the algorithm. |
---|
[891] | 899 | /// |
---|
| 900 | /// \tparam TR The traits class that defines various types used by the |
---|
| 901 | /// algorithm. |
---|
[100] | 902 | template<class TR> |
---|
| 903 | class DfsWizard : public TR |
---|
| 904 | { |
---|
| 905 | typedef TR Base; |
---|
| 906 | |
---|
| 907 | typedef typename TR::Digraph Digraph; |
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[244] | 908 | |
---|
[100] | 909 | typedef typename Digraph::Node Node; |
---|
| 910 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 911 | typedef typename Digraph::Arc Arc; |
---|
| 912 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
[209] | 913 | |
---|
[244] | 914 | typedef typename TR::PredMap PredMap; |
---|
| 915 | typedef typename TR::DistMap DistMap; |
---|
[100] | 916 | typedef typename TR::ReachedMap ReachedMap; |
---|
| 917 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
[278] | 918 | typedef typename TR::Path Path; |
---|
[100] | 919 | |
---|
| 920 | public: |
---|
[244] | 921 | |
---|
[100] | 922 | /// Constructor. |
---|
| 923 | DfsWizard() : TR() {} |
---|
| 924 | |
---|
| 925 | /// Constructor that requires parameters. |
---|
| 926 | |
---|
| 927 | /// Constructor that requires parameters. |
---|
| 928 | /// These parameters will be the default values for the traits class. |
---|
[278] | 929 | /// \param g The digraph the algorithm runs on. |
---|
| 930 | DfsWizard(const Digraph &g) : |
---|
| 931 | TR(g) {} |
---|
[100] | 932 | |
---|
| 933 | ///Copy constructor |
---|
| 934 | DfsWizard(const TR &b) : TR(b) {} |
---|
| 935 | |
---|
| 936 | ~DfsWizard() {} |
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| 937 | |
---|
[278] | 938 | ///Runs DFS algorithm from the given source node. |
---|
[209] | 939 | |
---|
[278] | 940 | ///This method runs DFS algorithm from node \c s |
---|
| 941 | ///in order to compute the DFS path to each node. |
---|
| 942 | void run(Node s) |
---|
| 943 | { |
---|
| 944 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 945 | if (Base::_pred) |
---|
| 946 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 947 | if (Base::_dist) |
---|
| 948 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 949 | if (Base::_reached) |
---|
| 950 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 951 | if (Base::_processed) |
---|
| 952 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 953 | if (s!=INVALID) |
---|
| 954 | alg.run(s); |
---|
| 955 | else |
---|
| 956 | alg.run(); |
---|
| 957 | } |
---|
| 958 | |
---|
| 959 | ///Finds the DFS path between \c s and \c t. |
---|
| 960 | |
---|
| 961 | ///This method runs DFS algorithm from node \c s |
---|
| 962 | ///in order to compute the DFS path to node \c t |
---|
| 963 | ///(it stops searching when \c t is processed). |
---|
| 964 | /// |
---|
| 965 | ///\return \c true if \c t is reachable form \c s. |
---|
| 966 | bool run(Node s, Node t) |
---|
| 967 | { |
---|
| 968 | Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 969 | if (Base::_pred) |
---|
| 970 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 971 | if (Base::_dist) |
---|
| 972 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 973 | if (Base::_reached) |
---|
| 974 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 975 | if (Base::_processed) |
---|
| 976 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 977 | alg.run(s,t); |
---|
| 978 | if (Base::_path) |
---|
| 979 | *reinterpret_cast<Path*>(Base::_path) = alg.path(t); |
---|
| 980 | if (Base::_di) |
---|
| 981 | *Base::_di = alg.dist(t); |
---|
| 982 | return alg.reached(t); |
---|
| 983 | } |
---|
| 984 | |
---|
| 985 | ///Runs DFS algorithm to visit all nodes in the digraph. |
---|
| 986 | |
---|
[834] | 987 | ///This method runs DFS algorithm in order to visit all nodes |
---|
| 988 | ///in the digraph. |
---|
[100] | 989 | void run() |
---|
| 990 | { |
---|
[278] | 991 | run(INVALID); |
---|
[244] | 992 | } |
---|
| 993 | |
---|
[100] | 994 | template<class T> |
---|
[257] | 995 | struct SetPredMapBase : public Base { |
---|
[100] | 996 | typedef T PredMap; |
---|
| 997 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
[257] | 998 | SetPredMapBase(const TR &b) : TR(b) {} |
---|
[100] | 999 | }; |
---|
[763] | 1000 | |
---|
| 1001 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
| 1002 | ///the predecessor map. |
---|
[100] | 1003 | /// |
---|
[763] | 1004 | ///\ref named-templ-param "Named parameter" function for setting |
---|
| 1005 | ///the map that stores the predecessor arcs of the nodes. |
---|
[100] | 1006 | template<class T> |
---|
[257] | 1007 | DfsWizard<SetPredMapBase<T> > predMap(const T &t) |
---|
[100] | 1008 | { |
---|
| 1009 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1010 | return DfsWizard<SetPredMapBase<T> >(*this); |
---|
[100] | 1011 | } |
---|
[209] | 1012 | |
---|
[100] | 1013 | template<class T> |
---|
[257] | 1014 | struct SetReachedMapBase : public Base { |
---|
[100] | 1015 | typedef T ReachedMap; |
---|
| 1016 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
[257] | 1017 | SetReachedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1018 | }; |
---|
[763] | 1019 | |
---|
| 1020 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
| 1021 | ///the reached map. |
---|
[100] | 1022 | /// |
---|
[763] | 1023 | ///\ref named-templ-param "Named parameter" function for setting |
---|
| 1024 | ///the map that indicates which nodes are reached. |
---|
[100] | 1025 | template<class T> |
---|
[257] | 1026 | DfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
---|
[100] | 1027 | { |
---|
[158] | 1028 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1029 | return DfsWizard<SetReachedMapBase<T> >(*this); |
---|
[100] | 1030 | } |
---|
[209] | 1031 | |
---|
[100] | 1032 | template<class T> |
---|
[278] | 1033 | struct SetDistMapBase : public Base { |
---|
| 1034 | typedef T DistMap; |
---|
| 1035 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
| 1036 | SetDistMapBase(const TR &b) : TR(b) {} |
---|
| 1037 | }; |
---|
[763] | 1038 | |
---|
| 1039 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
| 1040 | ///the distance map. |
---|
[278] | 1041 | /// |
---|
[763] | 1042 | ///\ref named-templ-param "Named parameter" function for setting |
---|
| 1043 | ///the map that stores the distances of the nodes calculated |
---|
| 1044 | ///by the algorithm. |
---|
[278] | 1045 | template<class T> |
---|
| 1046 | DfsWizard<SetDistMapBase<T> > distMap(const T &t) |
---|
| 1047 | { |
---|
| 1048 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1049 | return DfsWizard<SetDistMapBase<T> >(*this); |
---|
| 1050 | } |
---|
| 1051 | |
---|
| 1052 | template<class T> |
---|
[257] | 1053 | struct SetProcessedMapBase : public Base { |
---|
[100] | 1054 | typedef T ProcessedMap; |
---|
| 1055 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
[257] | 1056 | SetProcessedMapBase(const TR &b) : TR(b) {} |
---|
[100] | 1057 | }; |
---|
[763] | 1058 | |
---|
| 1059 | ///\brief \ref named-func-param "Named parameter" for setting |
---|
| 1060 | ///the processed map. |
---|
[100] | 1061 | /// |
---|
[763] | 1062 | ///\ref named-templ-param "Named parameter" function for setting |
---|
| 1063 | ///the map that indicates which nodes are processed. |
---|
[100] | 1064 | template<class T> |
---|
[257] | 1065 | DfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
---|
[100] | 1066 | { |
---|
[158] | 1067 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1068 | return DfsWizard<SetProcessedMapBase<T> >(*this); |
---|
[100] | 1069 | } |
---|
[209] | 1070 | |
---|
[100] | 1071 | template<class T> |
---|
[278] | 1072 | struct SetPathBase : public Base { |
---|
| 1073 | typedef T Path; |
---|
| 1074 | SetPathBase(const TR &b) : TR(b) {} |
---|
[100] | 1075 | }; |
---|
[278] | 1076 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1077 | ///for getting the DFS path to the target node. |
---|
[100] | 1078 | /// |
---|
[278] | 1079 | ///\ref named-func-param "Named parameter" |
---|
| 1080 | ///for getting the DFS path to the target node. |
---|
[100] | 1081 | template<class T> |
---|
[278] | 1082 | DfsWizard<SetPathBase<T> > path(const T &t) |
---|
[100] | 1083 | { |
---|
[278] | 1084 | Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1085 | return DfsWizard<SetPathBase<T> >(*this); |
---|
| 1086 | } |
---|
| 1087 | |
---|
| 1088 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1089 | ///for getting the distance of the target node. |
---|
| 1090 | /// |
---|
| 1091 | ///\ref named-func-param "Named parameter" |
---|
| 1092 | ///for getting the distance of the target node. |
---|
| 1093 | DfsWizard dist(const int &d) |
---|
| 1094 | { |
---|
| 1095 | Base::_di=const_cast<int*>(&d); |
---|
| 1096 | return *this; |
---|
[100] | 1097 | } |
---|
[209] | 1098 | |
---|
[100] | 1099 | }; |
---|
[209] | 1100 | |
---|
[278] | 1101 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1102 | |
---|
| 1103 | ///\ingroup search |
---|
[278] | 1104 | ///Function-type interface for DFS algorithm. |
---|
[100] | 1105 | /// |
---|
[278] | 1106 | ///This function also has several \ref named-func-param "named parameters", |
---|
[100] | 1107 | ///they are declared as the members of class \ref DfsWizard. |
---|
[278] | 1108 | ///The following examples show how to use these parameters. |
---|
[100] | 1109 | ///\code |
---|
[278] | 1110 | /// // Compute the DFS tree |
---|
| 1111 | /// dfs(g).predMap(preds).distMap(dists).run(s); |
---|
| 1112 | /// |
---|
| 1113 | /// // Compute the DFS path from s to t |
---|
| 1114 | /// bool reached = dfs(g).path(p).dist(d).run(s,t); |
---|
[100] | 1115 | ///\endcode |
---|
[421] | 1116 | ///\warning Don't forget to put the \ref DfsWizard::run(Node) "run()" |
---|
[100] | 1117 | ///to the end of the parameter list. |
---|
| 1118 | ///\sa DfsWizard |
---|
| 1119 | ///\sa Dfs |
---|
| 1120 | template<class GR> |
---|
| 1121 | DfsWizard<DfsWizardBase<GR> > |
---|
[278] | 1122 | dfs(const GR &digraph) |
---|
[100] | 1123 | { |
---|
[278] | 1124 | return DfsWizard<DfsWizardBase<GR> >(digraph); |
---|
[100] | 1125 | } |
---|
| 1126 | |
---|
| 1127 | #ifdef DOXYGEN |
---|
[244] | 1128 | /// \brief Visitor class for DFS. |
---|
[209] | 1129 | /// |
---|
[244] | 1130 | /// This class defines the interface of the DfsVisit events, and |
---|
| 1131 | /// it could be the base of a real visitor class. |
---|
[525] | 1132 | template <typename GR> |
---|
[100] | 1133 | struct DfsVisitor { |
---|
[525] | 1134 | typedef GR Digraph; |
---|
[100] | 1135 | typedef typename Digraph::Arc Arc; |
---|
| 1136 | typedef typename Digraph::Node Node; |
---|
[244] | 1137 | /// \brief Called for the source node of the DFS. |
---|
[209] | 1138 | /// |
---|
[244] | 1139 | /// This function is called for the source node of the DFS. |
---|
| 1140 | void start(const Node& node) {} |
---|
| 1141 | /// \brief Called when the source node is leaved. |
---|
| 1142 | /// |
---|
| 1143 | /// This function is called when the source node is leaved. |
---|
| 1144 | void stop(const Node& node) {} |
---|
| 1145 | /// \brief Called when a node is reached first time. |
---|
| 1146 | /// |
---|
| 1147 | /// This function is called when a node is reached first time. |
---|
| 1148 | void reach(const Node& node) {} |
---|
| 1149 | /// \brief Called when an arc reaches a new node. |
---|
| 1150 | /// |
---|
| 1151 | /// This function is called when the DFS finds an arc whose target node |
---|
| 1152 | /// is not reached yet. |
---|
[100] | 1153 | void discover(const Arc& arc) {} |
---|
[244] | 1154 | /// \brief Called when an arc is examined but its target node is |
---|
[100] | 1155 | /// already discovered. |
---|
[209] | 1156 | /// |
---|
[244] | 1157 | /// This function is called when an arc is examined but its target node is |
---|
[100] | 1158 | /// already discovered. |
---|
| 1159 | void examine(const Arc& arc) {} |
---|
[244] | 1160 | /// \brief Called when the DFS steps back from a node. |
---|
[209] | 1161 | /// |
---|
[244] | 1162 | /// This function is called when the DFS steps back from a node. |
---|
| 1163 | void leave(const Node& node) {} |
---|
| 1164 | /// \brief Called when the DFS steps back on an arc. |
---|
[209] | 1165 | /// |
---|
[244] | 1166 | /// This function is called when the DFS steps back on an arc. |
---|
| 1167 | void backtrack(const Arc& arc) {} |
---|
[100] | 1168 | }; |
---|
| 1169 | #else |
---|
[525] | 1170 | template <typename GR> |
---|
[100] | 1171 | struct DfsVisitor { |
---|
[525] | 1172 | typedef GR Digraph; |
---|
[100] | 1173 | typedef typename Digraph::Arc Arc; |
---|
| 1174 | typedef typename Digraph::Node Node; |
---|
| 1175 | void start(const Node&) {} |
---|
| 1176 | void stop(const Node&) {} |
---|
[244] | 1177 | void reach(const Node&) {} |
---|
| 1178 | void discover(const Arc&) {} |
---|
| 1179 | void examine(const Arc&) {} |
---|
| 1180 | void leave(const Node&) {} |
---|
| 1181 | void backtrack(const Arc&) {} |
---|
[100] | 1182 | |
---|
| 1183 | template <typename _Visitor> |
---|
| 1184 | struct Constraints { |
---|
| 1185 | void constraints() { |
---|
[209] | 1186 | Arc arc; |
---|
| 1187 | Node node; |
---|
| 1188 | visitor.start(node); |
---|
| 1189 | visitor.stop(arc); |
---|
[244] | 1190 | visitor.reach(node); |
---|
| 1191 | visitor.discover(arc); |
---|
| 1192 | visitor.examine(arc); |
---|
| 1193 | visitor.leave(node); |
---|
| 1194 | visitor.backtrack(arc); |
---|
[100] | 1195 | } |
---|
| 1196 | _Visitor& visitor; |
---|
[1125] | 1197 | Constraints() {} |
---|
[100] | 1198 | }; |
---|
| 1199 | }; |
---|
| 1200 | #endif |
---|
| 1201 | |
---|
| 1202 | /// \brief Default traits class of DfsVisit class. |
---|
| 1203 | /// |
---|
| 1204 | /// Default traits class of DfsVisit class. |
---|
[244] | 1205 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[525] | 1206 | template<class GR> |
---|
[100] | 1207 | struct DfsVisitDefaultTraits { |
---|
| 1208 | |
---|
[244] | 1209 | /// \brief The type of the digraph the algorithm runs on. |
---|
[525] | 1210 | typedef GR Digraph; |
---|
[100] | 1211 | |
---|
| 1212 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1213 | /// |
---|
[100] | 1214 | /// The type of the map that indicates which nodes are reached. |
---|
[956] | 1215 | /// It must conform to the |
---|
| 1216 | /// \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 1217 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1218 | |
---|
[301] | 1219 | /// \brief Instantiates a ReachedMap. |
---|
[100] | 1220 | /// |
---|
[301] | 1221 | /// This function instantiates a ReachedMap. |
---|
[100] | 1222 | /// \param digraph is the digraph, to which |
---|
[301] | 1223 | /// we would like to define the ReachedMap. |
---|
[100] | 1224 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1225 | return new ReachedMap(digraph); |
---|
| 1226 | } |
---|
| 1227 | |
---|
| 1228 | }; |
---|
[209] | 1229 | |
---|
[100] | 1230 | /// \ingroup search |
---|
[244] | 1231 | /// |
---|
[525] | 1232 | /// \brief DFS algorithm class with visitor interface. |
---|
[244] | 1233 | /// |
---|
[525] | 1234 | /// This class provides an efficient implementation of the DFS algorithm |
---|
[100] | 1235 | /// with visitor interface. |
---|
| 1236 | /// |
---|
[525] | 1237 | /// The DfsVisit class provides an alternative interface to the Dfs |
---|
[100] | 1238 | /// class. It works with callback mechanism, the DfsVisit object calls |
---|
[244] | 1239 | /// the member functions of the \c Visitor class on every DFS event. |
---|
[100] | 1240 | /// |
---|
[252] | 1241 | /// This interface of the DFS algorithm should be used in special cases |
---|
| 1242 | /// when extra actions have to be performed in connection with certain |
---|
| 1243 | /// events of the DFS algorithm. Otherwise consider to use Dfs or dfs() |
---|
| 1244 | /// instead. |
---|
| 1245 | /// |
---|
[525] | 1246 | /// \tparam GR The type of the digraph the algorithm runs on. |
---|
| 1247 | /// The default type is \ref ListDigraph. |
---|
| 1248 | /// The value of GR is not used directly by \ref DfsVisit, |
---|
| 1249 | /// it is only passed to \ref DfsVisitDefaultTraits. |
---|
| 1250 | /// \tparam VS The Visitor type that is used by the algorithm. |
---|
| 1251 | /// \ref DfsVisitor "DfsVisitor<GR>" is an empty visitor, which |
---|
[244] | 1252 | /// does not observe the DFS events. If you want to observe the DFS |
---|
| 1253 | /// events, you should implement your own visitor class. |
---|
[891] | 1254 | /// \tparam TR The traits class that defines various types used by the |
---|
| 1255 | /// algorithm. By default, it is \ref DfsVisitDefaultTraits |
---|
| 1256 | /// "DfsVisitDefaultTraits<GR>". |
---|
| 1257 | /// In most cases, this parameter should not be set directly, |
---|
| 1258 | /// consider to use the named template parameters instead. |
---|
[100] | 1259 | #ifdef DOXYGEN |
---|
[525] | 1260 | template <typename GR, typename VS, typename TR> |
---|
[100] | 1261 | #else |
---|
[525] | 1262 | template <typename GR = ListDigraph, |
---|
| 1263 | typename VS = DfsVisitor<GR>, |
---|
| 1264 | typename TR = DfsVisitDefaultTraits<GR> > |
---|
[100] | 1265 | #endif |
---|
| 1266 | class DfsVisit { |
---|
| 1267 | public: |
---|
[209] | 1268 | |
---|
[244] | 1269 | ///The traits class. |
---|
[525] | 1270 | typedef TR Traits; |
---|
[100] | 1271 | |
---|
[244] | 1272 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 1273 | typedef typename Traits::Digraph Digraph; |
---|
| 1274 | |
---|
[244] | 1275 | ///The visitor type used by the algorithm. |
---|
[525] | 1276 | typedef VS Visitor; |
---|
[100] | 1277 | |
---|
[244] | 1278 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 1279 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1280 | |
---|
| 1281 | private: |
---|
| 1282 | |
---|
| 1283 | typedef typename Digraph::Node Node; |
---|
| 1284 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1285 | typedef typename Digraph::Arc Arc; |
---|
| 1286 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1287 | |
---|
[244] | 1288 | //Pointer to the underlying digraph. |
---|
[100] | 1289 | const Digraph *_digraph; |
---|
[244] | 1290 | //Pointer to the visitor object. |
---|
[100] | 1291 | Visitor *_visitor; |
---|
[244] | 1292 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 1293 | ReachedMap *_reached; |
---|
[244] | 1294 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 1295 | bool local_reached; |
---|
| 1296 | |
---|
| 1297 | std::vector<typename Digraph::Arc> _stack; |
---|
| 1298 | int _stack_head; |
---|
| 1299 | |
---|
[280] | 1300 | //Creates the maps if necessary. |
---|
[100] | 1301 | void create_maps() { |
---|
| 1302 | if(!_reached) { |
---|
[209] | 1303 | local_reached = true; |
---|
| 1304 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1305 | } |
---|
| 1306 | } |
---|
| 1307 | |
---|
| 1308 | protected: |
---|
| 1309 | |
---|
| 1310 | DfsVisit() {} |
---|
[209] | 1311 | |
---|
[100] | 1312 | public: |
---|
| 1313 | |
---|
| 1314 | typedef DfsVisit Create; |
---|
| 1315 | |
---|
[421] | 1316 | /// \name Named Template Parameters |
---|
[100] | 1317 | |
---|
| 1318 | ///@{ |
---|
| 1319 | template <class T> |
---|
[257] | 1320 | struct SetReachedMapTraits : public Traits { |
---|
[100] | 1321 | typedef T ReachedMap; |
---|
[1416] | 1322 | static ReachedMap *createReachedMap(const Digraph &) { |
---|
[290] | 1323 | LEMON_ASSERT(false, "ReachedMap is not initialized"); |
---|
| 1324 | return 0; // ignore warnings |
---|
[100] | 1325 | } |
---|
| 1326 | }; |
---|
[209] | 1327 | /// \brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 1328 | /// ReachedMap type. |
---|
[100] | 1329 | /// |
---|
[244] | 1330 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
---|
[100] | 1331 | template <class T> |
---|
[257] | 1332 | struct SetReachedMap : public DfsVisit< Digraph, Visitor, |
---|
| 1333 | SetReachedMapTraits<T> > { |
---|
| 1334 | typedef DfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
---|
[100] | 1335 | }; |
---|
| 1336 | ///@} |
---|
| 1337 | |
---|
[209] | 1338 | public: |
---|
| 1339 | |
---|
[100] | 1340 | /// \brief Constructor. |
---|
| 1341 | /// |
---|
| 1342 | /// Constructor. |
---|
| 1343 | /// |
---|
[244] | 1344 | /// \param digraph The digraph the algorithm runs on. |
---|
| 1345 | /// \param visitor The visitor object of the algorithm. |
---|
[209] | 1346 | DfsVisit(const Digraph& digraph, Visitor& visitor) |
---|
[100] | 1347 | : _digraph(&digraph), _visitor(&visitor), |
---|
[209] | 1348 | _reached(0), local_reached(false) {} |
---|
| 1349 | |
---|
[100] | 1350 | /// \brief Destructor. |
---|
| 1351 | ~DfsVisit() { |
---|
| 1352 | if(local_reached) delete _reached; |
---|
| 1353 | } |
---|
| 1354 | |
---|
[244] | 1355 | /// \brief Sets the map that indicates which nodes are reached. |
---|
[100] | 1356 | /// |
---|
[244] | 1357 | /// Sets the map that indicates which nodes are reached. |
---|
[421] | 1358 | /// If you don't use this function before calling \ref run(Node) "run()" |
---|
| 1359 | /// or \ref init(), an instance will be allocated automatically. |
---|
| 1360 | /// The destructor deallocates this automatically allocated map, |
---|
| 1361 | /// of course. |
---|
[100] | 1362 | /// \return <tt> (*this) </tt> |
---|
| 1363 | DfsVisit &reachedMap(ReachedMap &m) { |
---|
| 1364 | if(local_reached) { |
---|
[209] | 1365 | delete _reached; |
---|
| 1366 | local_reached=false; |
---|
[100] | 1367 | } |
---|
| 1368 | _reached = &m; |
---|
| 1369 | return *this; |
---|
| 1370 | } |
---|
| 1371 | |
---|
| 1372 | public: |
---|
[244] | 1373 | |
---|
[421] | 1374 | /// \name Execution Control |
---|
| 1375 | /// The simplest way to execute the DFS algorithm is to use one of the |
---|
| 1376 | /// member functions called \ref run(Node) "run()".\n |
---|
[760] | 1377 | /// If you need better control on the execution, you have to call |
---|
| 1378 | /// \ref init() first, then you can add a source node with \ref addSource() |
---|
[421] | 1379 | /// and perform the actual computation with \ref start(). |
---|
| 1380 | /// This procedure can be repeated if there are nodes that have not |
---|
| 1381 | /// been reached. |
---|
[100] | 1382 | |
---|
| 1383 | /// @{ |
---|
[244] | 1384 | |
---|
[100] | 1385 | /// \brief Initializes the internal data structures. |
---|
| 1386 | /// |
---|
| 1387 | /// Initializes the internal data structures. |
---|
| 1388 | void init() { |
---|
| 1389 | create_maps(); |
---|
| 1390 | _stack.resize(countNodes(*_digraph)); |
---|
| 1391 | _stack_head = -1; |
---|
| 1392 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
---|
[209] | 1393 | _reached->set(u, false); |
---|
[100] | 1394 | } |
---|
| 1395 | } |
---|
[209] | 1396 | |
---|
[421] | 1397 | /// \brief Adds a new source node. |
---|
[100] | 1398 | /// |
---|
[421] | 1399 | /// Adds a new source node to the set of nodes to be processed. |
---|
[244] | 1400 | /// |
---|
[421] | 1401 | /// \pre The stack must be empty. Otherwise the algorithm gives |
---|
| 1402 | /// wrong results. (One of the outgoing arcs of all the source nodes |
---|
| 1403 | /// except for the last one will not be visited and distances will |
---|
| 1404 | /// also be wrong.) |
---|
[244] | 1405 | void addSource(Node s) |
---|
| 1406 | { |
---|
| 1407 | LEMON_DEBUG(emptyQueue(), "The stack is not empty."); |
---|
[100] | 1408 | if(!(*_reached)[s]) { |
---|
[209] | 1409 | _reached->set(s,true); |
---|
| 1410 | _visitor->start(s); |
---|
| 1411 | _visitor->reach(s); |
---|
| 1412 | Arc e; |
---|
| 1413 | _digraph->firstOut(e, s); |
---|
| 1414 | if (e != INVALID) { |
---|
| 1415 | _stack[++_stack_head] = e; |
---|
| 1416 | } else { |
---|
| 1417 | _visitor->leave(s); |
---|
[435] | 1418 | _visitor->stop(s); |
---|
[209] | 1419 | } |
---|
| 1420 | } |
---|
[100] | 1421 | } |
---|
[209] | 1422 | |
---|
[100] | 1423 | /// \brief Processes the next arc. |
---|
| 1424 | /// |
---|
| 1425 | /// Processes the next arc. |
---|
| 1426 | /// |
---|
| 1427 | /// \return The processed arc. |
---|
| 1428 | /// |
---|
[244] | 1429 | /// \pre The stack must not be empty. |
---|
[209] | 1430 | Arc processNextArc() { |
---|
[100] | 1431 | Arc e = _stack[_stack_head]; |
---|
| 1432 | Node m = _digraph->target(e); |
---|
| 1433 | if(!(*_reached)[m]) { |
---|
[209] | 1434 | _visitor->discover(e); |
---|
| 1435 | _visitor->reach(m); |
---|
| 1436 | _reached->set(m, true); |
---|
| 1437 | _digraph->firstOut(_stack[++_stack_head], m); |
---|
[100] | 1438 | } else { |
---|
[209] | 1439 | _visitor->examine(e); |
---|
| 1440 | m = _digraph->source(e); |
---|
| 1441 | _digraph->nextOut(_stack[_stack_head]); |
---|
[100] | 1442 | } |
---|
| 1443 | while (_stack_head>=0 && _stack[_stack_head] == INVALID) { |
---|
[209] | 1444 | _visitor->leave(m); |
---|
| 1445 | --_stack_head; |
---|
| 1446 | if (_stack_head >= 0) { |
---|
| 1447 | _visitor->backtrack(_stack[_stack_head]); |
---|
| 1448 | m = _digraph->source(_stack[_stack_head]); |
---|
| 1449 | _digraph->nextOut(_stack[_stack_head]); |
---|
| 1450 | } else { |
---|
| 1451 | _visitor->stop(m); |
---|
| 1452 | } |
---|
[100] | 1453 | } |
---|
| 1454 | return e; |
---|
| 1455 | } |
---|
| 1456 | |
---|
| 1457 | /// \brief Next arc to be processed. |
---|
| 1458 | /// |
---|
| 1459 | /// Next arc to be processed. |
---|
| 1460 | /// |
---|
| 1461 | /// \return The next arc to be processed or INVALID if the stack is |
---|
| 1462 | /// empty. |
---|
[244] | 1463 | Arc nextArc() const { |
---|
[100] | 1464 | return _stack_head >= 0 ? _stack[_stack_head] : INVALID; |
---|
| 1465 | } |
---|
| 1466 | |
---|
| 1467 | /// \brief Returns \c false if there are nodes |
---|
[244] | 1468 | /// to be processed. |
---|
[100] | 1469 | /// |
---|
| 1470 | /// Returns \c false if there are nodes |
---|
[244] | 1471 | /// to be processed in the queue (stack). |
---|
| 1472 | bool emptyQueue() const { return _stack_head < 0; } |
---|
[100] | 1473 | |
---|
| 1474 | /// \brief Returns the number of the nodes to be processed. |
---|
| 1475 | /// |
---|
[244] | 1476 | /// Returns the number of the nodes to be processed in the queue (stack). |
---|
| 1477 | int queueSize() const { return _stack_head + 1; } |
---|
[209] | 1478 | |
---|
[100] | 1479 | /// \brief Executes the algorithm. |
---|
| 1480 | /// |
---|
| 1481 | /// Executes the algorithm. |
---|
| 1482 | /// |
---|
[244] | 1483 | /// This method runs the %DFS algorithm from the root node |
---|
| 1484 | /// in order to compute the %DFS path to each node. |
---|
| 1485 | /// |
---|
| 1486 | /// The algorithm computes |
---|
| 1487 | /// - the %DFS tree, |
---|
| 1488 | /// - the distance of each node from the root in the %DFS tree. |
---|
| 1489 | /// |
---|
| 1490 | /// \pre init() must be called and a root node should be |
---|
| 1491 | /// added with addSource() before using this function. |
---|
| 1492 | /// |
---|
| 1493 | /// \note <tt>d.start()</tt> is just a shortcut of the following code. |
---|
| 1494 | /// \code |
---|
| 1495 | /// while ( !d.emptyQueue() ) { |
---|
| 1496 | /// d.processNextArc(); |
---|
| 1497 | /// } |
---|
| 1498 | /// \endcode |
---|
[100] | 1499 | void start() { |
---|
| 1500 | while ( !emptyQueue() ) processNextArc(); |
---|
| 1501 | } |
---|
[209] | 1502 | |
---|
[244] | 1503 | /// \brief Executes the algorithm until the given target node is reached. |
---|
[100] | 1504 | /// |
---|
[244] | 1505 | /// Executes the algorithm until the given target node is reached. |
---|
[100] | 1506 | /// |
---|
[244] | 1507 | /// This method runs the %DFS algorithm from the root node |
---|
[286] | 1508 | /// in order to compute the DFS path to \c t. |
---|
[244] | 1509 | /// |
---|
| 1510 | /// The algorithm computes |
---|
[286] | 1511 | /// - the %DFS path to \c t, |
---|
| 1512 | /// - the distance of \c t from the root in the %DFS tree. |
---|
[244] | 1513 | /// |
---|
| 1514 | /// \pre init() must be called and a root node should be added |
---|
[100] | 1515 | /// with addSource() before using this function. |
---|
[286] | 1516 | void start(Node t) { |
---|
[1007] | 1517 | while ( !emptyQueue() && !(*_reached)[t] ) |
---|
[209] | 1518 | processNextArc(); |
---|
[100] | 1519 | } |
---|
[209] | 1520 | |
---|
[100] | 1521 | /// \brief Executes the algorithm until a condition is met. |
---|
| 1522 | /// |
---|
| 1523 | /// Executes the algorithm until a condition is met. |
---|
| 1524 | /// |
---|
[244] | 1525 | /// This method runs the %DFS algorithm from the root node |
---|
| 1526 | /// until an arc \c a with <tt>am[a]</tt> true is found. |
---|
| 1527 | /// |
---|
| 1528 | /// \param am A \c bool (or convertible) arc map. The algorithm |
---|
| 1529 | /// will stop when it reaches an arc \c a with <tt>am[a]</tt> true. |
---|
| 1530 | /// |
---|
| 1531 | /// \return The reached arc \c a with <tt>am[a]</tt> true or |
---|
| 1532 | /// \c INVALID if no such arc was found. |
---|
| 1533 | /// |
---|
| 1534 | /// \pre init() must be called and a root node should be added |
---|
[100] | 1535 | /// with addSource() before using this function. |
---|
| 1536 | /// |
---|
[244] | 1537 | /// \warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, |
---|
[100] | 1538 | /// not a node map. |
---|
[244] | 1539 | template <typename AM> |
---|
| 1540 | Arc start(const AM &am) { |
---|
| 1541 | while ( !emptyQueue() && !am[_stack[_stack_head]] ) |
---|
[100] | 1542 | processNextArc(); |
---|
| 1543 | return emptyQueue() ? INVALID : _stack[_stack_head]; |
---|
| 1544 | } |
---|
| 1545 | |
---|
[286] | 1546 | /// \brief Runs the algorithm from the given source node. |
---|
[100] | 1547 | /// |
---|
[244] | 1548 | /// This method runs the %DFS algorithm from node \c s. |
---|
| 1549 | /// in order to compute the DFS path to each node. |
---|
| 1550 | /// |
---|
| 1551 | /// The algorithm computes |
---|
| 1552 | /// - the %DFS tree, |
---|
| 1553 | /// - the distance of each node from the root in the %DFS tree. |
---|
| 1554 | /// |
---|
| 1555 | /// \note <tt>d.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1556 | ///\code |
---|
| 1557 | /// d.init(); |
---|
| 1558 | /// d.addSource(s); |
---|
| 1559 | /// d.start(); |
---|
| 1560 | ///\endcode |
---|
| 1561 | void run(Node s) { |
---|
| 1562 | init(); |
---|
| 1563 | addSource(s); |
---|
| 1564 | start(); |
---|
| 1565 | } |
---|
| 1566 | |
---|
[244] | 1567 | /// \brief Finds the %DFS path between \c s and \c t. |
---|
| 1568 | |
---|
| 1569 | /// This method runs the %DFS algorithm from node \c s |
---|
[286] | 1570 | /// in order to compute the DFS path to node \c t |
---|
| 1571 | /// (it stops searching when \c t is processed). |
---|
[244] | 1572 | /// |
---|
[286] | 1573 | /// \return \c true if \c t is reachable form \c s. |
---|
[244] | 1574 | /// |
---|
| 1575 | /// \note Apart from the return value, <tt>d.run(s,t)</tt> is |
---|
| 1576 | /// just a shortcut of the following code. |
---|
| 1577 | ///\code |
---|
| 1578 | /// d.init(); |
---|
| 1579 | /// d.addSource(s); |
---|
| 1580 | /// d.start(t); |
---|
| 1581 | ///\endcode |
---|
[286] | 1582 | bool run(Node s,Node t) { |
---|
[244] | 1583 | init(); |
---|
| 1584 | addSource(s); |
---|
| 1585 | start(t); |
---|
[286] | 1586 | return reached(t); |
---|
[244] | 1587 | } |
---|
| 1588 | |
---|
| 1589 | /// \brief Runs the algorithm to visit all nodes in the digraph. |
---|
[209] | 1590 | |
---|
[834] | 1591 | /// This method runs the %DFS algorithm in order to visit all nodes |
---|
| 1592 | /// in the digraph. |
---|
[244] | 1593 | /// |
---|
| 1594 | /// \note <tt>d.run()</tt> is just a shortcut of the following code. |
---|
[100] | 1595 | ///\code |
---|
[244] | 1596 | /// d.init(); |
---|
| 1597 | /// for (NodeIt n(digraph); n != INVALID; ++n) { |
---|
| 1598 | /// if (!d.reached(n)) { |
---|
| 1599 | /// d.addSource(n); |
---|
| 1600 | /// d.start(); |
---|
| 1601 | /// } |
---|
| 1602 | /// } |
---|
[100] | 1603 | ///\endcode |
---|
| 1604 | void run() { |
---|
| 1605 | init(); |
---|
| 1606 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
| 1607 | if (!reached(it)) { |
---|
| 1608 | addSource(it); |
---|
| 1609 | start(); |
---|
| 1610 | } |
---|
| 1611 | } |
---|
| 1612 | } |
---|
[244] | 1613 | |
---|
[100] | 1614 | ///@} |
---|
| 1615 | |
---|
| 1616 | /// \name Query Functions |
---|
[421] | 1617 | /// The results of the DFS algorithm can be obtained using these |
---|
[100] | 1618 | /// functions.\n |
---|
[421] | 1619 | /// Either \ref run(Node) "run()" or \ref start() should be called |
---|
| 1620 | /// before using them. |
---|
| 1621 | |
---|
[100] | 1622 | ///@{ |
---|
[244] | 1623 | |
---|
[763] | 1624 | /// \brief Checks if the given node is reached from the root(s). |
---|
[100] | 1625 | /// |
---|
[421] | 1626 | /// Returns \c true if \c v is reached from the root(s). |
---|
| 1627 | /// |
---|
| 1628 | /// \pre Either \ref run(Node) "run()" or \ref init() |
---|
[100] | 1629 | /// must be called before using this function. |
---|
[437] | 1630 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[244] | 1631 | |
---|
[100] | 1632 | ///@} |
---|
[244] | 1633 | |
---|
[100] | 1634 | }; |
---|
| 1635 | |
---|
| 1636 | } //END OF NAMESPACE LEMON |
---|
| 1637 | |
---|
| 1638 | #endif |
---|