[209] | 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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[100] | 2 | * |
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[209] | 3 | * This file is a part of LEMON, a generic C++ optimization library. |
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[100] | 4 | * |
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| 5 | * Copyright (C) 2003-2008 |
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| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | #ifndef LEMON_BFS_H |
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| 20 | #define LEMON_BFS_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 BFS 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 Bfs class. |
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| 36 | |
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| 37 | ///Default traits class of Bfs 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 BfsDefaultTraits |
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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 shortest 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 shortest paths. |
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| 50 | ///It must meet 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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| 52 | ///Instantiates a \ref PredMap. |
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[209] | 53 | |
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| 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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| 56 | ///\ref PredMap. |
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[100] | 57 | ///\todo The digraph alone may be insufficient to initialize |
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[244] | 58 | static PredMap *createPredMap(const Digraph &g) |
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[100] | 59 | { |
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[244] | 60 | return new PredMap(g); |
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[100] | 61 | } |
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[244] | 62 | |
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[100] | 63 | ///The type of the map that indicates which nodes are processed. |
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[209] | 64 | |
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[100] | 65 | ///The type of the map that indicates which nodes are processed. |
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| 66 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[244] | 67 | ///By default it is a NullMap. |
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[100] | 68 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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[244] | 69 | ///Instantiates a \ref ProcessedMap. |
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[209] | 70 | |
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| 71 | ///This function instantiates a \ref ProcessedMap. |
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[100] | 72 | ///\param g is the digraph, to which |
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| 73 | ///we would like to define the \ref ProcessedMap |
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| 74 | #ifdef DOXYGEN |
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[244] | 75 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 76 | #else |
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[244] | 77 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 78 | #endif |
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| 79 | { |
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| 80 | return new ProcessedMap(); |
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| 81 | } |
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[244] | 82 | |
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[100] | 83 | ///The type of the map that indicates which nodes are reached. |
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[209] | 84 | |
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[100] | 85 | ///The type of the map that indicates which nodes are reached. |
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[244] | 86 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 87 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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[244] | 88 | ///Instantiates a \ref ReachedMap. |
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[209] | 89 | |
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| 90 | ///This function instantiates a \ref ReachedMap. |
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[244] | 91 | ///\param g is the digraph, to which |
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[100] | 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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[100] | 101 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 102 | typedef typename Digraph::template NodeMap<int> DistMap; |
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[244] | 103 | ///Instantiates a \ref DistMap. |
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[209] | 104 | |
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| 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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| 107 | ///\ref DistMap. |
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| 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 | ///%BFS 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 %BFS algorithm. |
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| 118 | /// |
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[278] | 119 | ///There is also a \ref bfs() "function-type interface" for the BFS |
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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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| 124 | ///The default value is \ref ListDigraph. The value of GR is not used |
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| 125 | ///directly by \ref Bfs, it is only passed to \ref BfsDefaultTraits. |
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[157] | 126 | ///\tparam TR Traits class to set various data types used by the algorithm. |
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[100] | 127 | ///The default traits class is |
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| 128 | ///\ref BfsDefaultTraits "BfsDefaultTraits<GR>". |
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| 129 | ///See \ref BfsDefaultTraits for the documentation of |
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| 130 | ///a Bfs traits class. |
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| 131 | #ifdef DOXYGEN |
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| 132 | template <typename GR, |
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[209] | 133 | typename TR> |
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[100] | 134 | #else |
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| 135 | template <typename GR=ListDigraph, |
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[209] | 136 | typename TR=BfsDefaultTraits<GR> > |
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[100] | 137 | #endif |
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| 138 | class Bfs { |
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| 139 | public: |
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[244] | 140 | ///\ref Exception for uninitialized parameters. |
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| 141 | |
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| 142 | ///This error represents problems in the initialization of the |
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| 143 | ///parameters of the algorithm. |
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[100] | 144 | class UninitializedParameter : public lemon::UninitializedParameter { |
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| 145 | public: |
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| 146 | virtual const char* what() const throw() { |
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[209] | 147 | return "lemon::Bfs::UninitializedParameter"; |
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[100] | 148 | } |
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| 149 | }; |
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| 150 | |
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[244] | 151 | ///The type of the digraph the algorithm runs on. |
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[100] | 152 | typedef typename TR::Digraph Digraph; |
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[209] | 153 | |
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[244] | 154 | ///\brief The type of the map that stores the predecessor arcs of the |
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| 155 | ///shortest paths. |
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[100] | 156 | typedef typename TR::PredMap PredMap; |
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[244] | 157 | ///The type of the map that stores the distances of the nodes. |
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| 158 | typedef typename TR::DistMap DistMap; |
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| 159 | ///The type of the map that indicates which nodes are reached. |
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[100] | 160 | typedef typename TR::ReachedMap ReachedMap; |
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[244] | 161 | ///The type of the map that indicates which nodes are processed. |
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[100] | 162 | typedef typename TR::ProcessedMap ProcessedMap; |
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[244] | 163 | ///The type of the paths. |
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| 164 | typedef PredMapPath<Digraph, PredMap> Path; |
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| 165 | |
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| 166 | ///The traits class. |
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| 167 | typedef TR Traits; |
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| 168 | |
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[100] | 169 | private: |
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| 170 | |
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| 171 | typedef typename Digraph::Node Node; |
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| 172 | typedef typename Digraph::NodeIt NodeIt; |
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| 173 | typedef typename Digraph::Arc Arc; |
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| 174 | typedef typename Digraph::OutArcIt OutArcIt; |
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| 175 | |
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[244] | 176 | //Pointer to the underlying digraph. |
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[100] | 177 | const Digraph *G; |
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[244] | 178 | //Pointer to the map of predecessor arcs. |
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[100] | 179 | PredMap *_pred; |
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[244] | 180 | //Indicates if _pred is locally allocated (true) or not. |
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[100] | 181 | bool local_pred; |
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[244] | 182 | //Pointer to the map of distances. |
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[100] | 183 | DistMap *_dist; |
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[244] | 184 | //Indicates if _dist is locally allocated (true) or not. |
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[100] | 185 | bool local_dist; |
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[244] | 186 | //Pointer to the map of reached status of the nodes. |
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[100] | 187 | ReachedMap *_reached; |
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[244] | 188 | //Indicates if _reached is locally allocated (true) or not. |
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[100] | 189 | bool local_reached; |
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[244] | 190 | //Pointer to the map of processed status of the nodes. |
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[100] | 191 | ProcessedMap *_processed; |
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[244] | 192 | //Indicates if _processed is locally allocated (true) or not. |
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[100] | 193 | bool local_processed; |
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| 194 | |
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| 195 | std::vector<typename Digraph::Node> _queue; |
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| 196 | int _queue_head,_queue_tail,_queue_next_dist; |
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| 197 | int _curr_dist; |
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| 198 | |
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| 199 | ///Creates the maps if necessary. |
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| 200 | ///\todo Better memory allocation (instead of new). |
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[209] | 201 | void create_maps() |
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[100] | 202 | { |
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| 203 | if(!_pred) { |
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[209] | 204 | local_pred = true; |
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| 205 | _pred = Traits::createPredMap(*G); |
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[100] | 206 | } |
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| 207 | if(!_dist) { |
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[209] | 208 | local_dist = true; |
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| 209 | _dist = Traits::createDistMap(*G); |
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[100] | 210 | } |
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| 211 | if(!_reached) { |
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[209] | 212 | local_reached = true; |
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| 213 | _reached = Traits::createReachedMap(*G); |
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[100] | 214 | } |
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| 215 | if(!_processed) { |
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[209] | 216 | local_processed = true; |
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| 217 | _processed = Traits::createProcessedMap(*G); |
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[100] | 218 | } |
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| 219 | } |
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| 220 | |
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| 221 | protected: |
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[209] | 222 | |
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[100] | 223 | Bfs() {} |
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[209] | 224 | |
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[100] | 225 | public: |
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[209] | 226 | |
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[100] | 227 | typedef Bfs Create; |
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| 228 | |
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| 229 | ///\name Named template parameters |
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| 230 | |
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| 231 | ///@{ |
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| 232 | |
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| 233 | template <class T> |
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[257] | 234 | struct SetPredMapTraits : public Traits { |
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[100] | 235 | typedef T PredMap; |
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[209] | 236 | static PredMap *createPredMap(const Digraph &) |
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[100] | 237 | { |
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[209] | 238 | throw UninitializedParameter(); |
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[100] | 239 | } |
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| 240 | }; |
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| 241 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 242 | ///\ref PredMap type. |
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[100] | 243 | /// |
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[244] | 244 | ///\ref named-templ-param "Named parameter" for setting |
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| 245 | ///\ref PredMap type. |
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[100] | 246 | template <class T> |
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[257] | 247 | struct SetPredMap : public Bfs< Digraph, SetPredMapTraits<T> > { |
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| 248 | typedef Bfs< Digraph, SetPredMapTraits<T> > Create; |
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[100] | 249 | }; |
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[209] | 250 | |
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[100] | 251 | template <class T> |
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[257] | 252 | struct SetDistMapTraits : public Traits { |
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[100] | 253 | typedef T DistMap; |
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[209] | 254 | static DistMap *createDistMap(const Digraph &) |
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[100] | 255 | { |
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[209] | 256 | throw UninitializedParameter(); |
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[100] | 257 | } |
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| 258 | }; |
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| 259 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 260 | ///\ref DistMap type. |
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[100] | 261 | /// |
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[244] | 262 | ///\ref named-templ-param "Named parameter" for setting |
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| 263 | ///\ref DistMap type. |
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[100] | 264 | template <class T> |
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[257] | 265 | struct SetDistMap : public Bfs< Digraph, SetDistMapTraits<T> > { |
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| 266 | typedef Bfs< Digraph, SetDistMapTraits<T> > Create; |
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[100] | 267 | }; |
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[209] | 268 | |
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[100] | 269 | template <class T> |
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[257] | 270 | struct SetReachedMapTraits : public Traits { |
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[100] | 271 | typedef T ReachedMap; |
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[209] | 272 | static ReachedMap *createReachedMap(const Digraph &) |
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[100] | 273 | { |
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[209] | 274 | throw UninitializedParameter(); |
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[100] | 275 | } |
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| 276 | }; |
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| 277 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 278 | ///\ref ReachedMap type. |
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[100] | 279 | /// |
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[244] | 280 | ///\ref named-templ-param "Named parameter" for setting |
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| 281 | ///\ref ReachedMap type. |
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[100] | 282 | template <class T> |
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[257] | 283 | struct SetReachedMap : public Bfs< Digraph, SetReachedMapTraits<T> > { |
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| 284 | typedef Bfs< Digraph, SetReachedMapTraits<T> > Create; |
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[100] | 285 | }; |
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[209] | 286 | |
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[100] | 287 | template <class T> |
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[257] | 288 | struct SetProcessedMapTraits : public Traits { |
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[100] | 289 | typedef T ProcessedMap; |
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[209] | 290 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 291 | { |
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[209] | 292 | throw UninitializedParameter(); |
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[100] | 293 | } |
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| 294 | }; |
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| 295 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 296 | ///\ref ProcessedMap type. |
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[100] | 297 | /// |
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[244] | 298 | ///\ref named-templ-param "Named parameter" for setting |
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| 299 | ///\ref ProcessedMap type. |
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[100] | 300 | template <class T> |
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[257] | 301 | struct SetProcessedMap : public Bfs< Digraph, SetProcessedMapTraits<T> > { |
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| 302 | typedef Bfs< Digraph, SetProcessedMapTraits<T> > Create; |
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[100] | 303 | }; |
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[209] | 304 | |
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[257] | 305 | struct SetStandardProcessedMapTraits : public Traits { |
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[100] | 306 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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[244] | 307 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 308 | { |
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[244] | 309 | return new ProcessedMap(g); |
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[100] | 310 | } |
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| 311 | }; |
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[244] | 312 | ///\brief \ref named-templ-param "Named parameter" for setting |
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| 313 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 314 | /// |
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[244] | 315 | ///\ref named-templ-param "Named parameter" for setting |
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| 316 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 317 | ///If you don't set it explicitly, it will be automatically allocated. |
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[257] | 318 | struct SetStandardProcessedMap : |
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| 319 | public Bfs< Digraph, SetStandardProcessedMapTraits > { |
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| 320 | typedef Bfs< Digraph, SetStandardProcessedMapTraits > Create; |
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[100] | 321 | }; |
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[209] | 322 | |
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[100] | 323 | ///@} |
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| 324 | |
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[209] | 325 | public: |
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| 326 | |
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[100] | 327 | ///Constructor. |
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[209] | 328 | |
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[244] | 329 | ///Constructor. |
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| 330 | ///\param g The digraph the algorithm runs on. |
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| 331 | Bfs(const Digraph &g) : |
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| 332 | G(&g), |
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[100] | 333 | _pred(NULL), local_pred(false), |
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| 334 | _dist(NULL), local_dist(false), |
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| 335 | _reached(NULL), local_reached(false), |
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| 336 | _processed(NULL), local_processed(false) |
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| 337 | { } |
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[209] | 338 | |
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[100] | 339 | ///Destructor. |
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[209] | 340 | ~Bfs() |
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[100] | 341 | { |
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| 342 | if(local_pred) delete _pred; |
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| 343 | if(local_dist) delete _dist; |
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| 344 | if(local_reached) delete _reached; |
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| 345 | if(local_processed) delete _processed; |
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| 346 | } |
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| 347 | |
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[244] | 348 | ///Sets the map that stores the predecessor arcs. |
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[100] | 349 | |
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[244] | 350 | ///Sets the map that stores the predecessor arcs. |
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[100] | 351 | ///If you don't use this function before calling \ref run(), |
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| 352 | ///it will allocate one. The destructor deallocates this |
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| 353 | ///automatically allocated map, of course. |
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| 354 | ///\return <tt> (*this) </tt> |
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[209] | 355 | Bfs &predMap(PredMap &m) |
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[100] | 356 | { |
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| 357 | if(local_pred) { |
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[209] | 358 | delete _pred; |
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| 359 | local_pred=false; |
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[100] | 360 | } |
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| 361 | _pred = &m; |
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| 362 | return *this; |
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| 363 | } |
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| 364 | |
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[244] | 365 | ///Sets the map that indicates which nodes are reached. |
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[100] | 366 | |
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[244] | 367 | ///Sets the map that indicates which nodes are reached. |
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[100] | 368 | ///If you don't use this function before calling \ref run(), |
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| 369 | ///it will allocate one. The destructor deallocates this |
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| 370 | ///automatically allocated map, of course. |
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| 371 | ///\return <tt> (*this) </tt> |
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[209] | 372 | Bfs &reachedMap(ReachedMap &m) |
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[100] | 373 | { |
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| 374 | if(local_reached) { |
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[209] | 375 | delete _reached; |
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| 376 | local_reached=false; |
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[100] | 377 | } |
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| 378 | _reached = &m; |
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| 379 | return *this; |
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| 380 | } |
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| 381 | |
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[244] | 382 | ///Sets the map that indicates which nodes are processed. |
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[100] | 383 | |
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[244] | 384 | ///Sets the map that indicates which nodes are processed. |
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[100] | 385 | ///If you don't use this function before calling \ref run(), |
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| 386 | ///it will allocate one. The destructor deallocates this |
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| 387 | ///automatically allocated map, of course. |
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| 388 | ///\return <tt> (*this) </tt> |
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[209] | 389 | Bfs &processedMap(ProcessedMap &m) |
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[100] | 390 | { |
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| 391 | if(local_processed) { |
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[209] | 392 | delete _processed; |
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| 393 | local_processed=false; |
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[100] | 394 | } |
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| 395 | _processed = &m; |
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| 396 | return *this; |
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| 397 | } |
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| 398 | |
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[244] | 399 | ///Sets the map that stores the distances of the nodes. |
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[100] | 400 | |
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[244] | 401 | ///Sets the map that stores the distances of the nodes calculated by |
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| 402 | ///the algorithm. |
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[100] | 403 | ///If you don't use this function before calling \ref run(), |
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| 404 | ///it will allocate one. The destructor deallocates this |
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| 405 | ///automatically allocated map, of course. |
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| 406 | ///\return <tt> (*this) </tt> |
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[209] | 407 | Bfs &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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| 417 | public: |
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[244] | 418 | |
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[100] | 419 | ///\name Execution control |
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| 420 | ///The simplest way to execute the algorithm is to use |
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[244] | 421 | ///one of the member functions called \ref lemon::Bfs::run() "run()". |
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[100] | 422 | ///\n |
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[244] | 423 | ///If you need more control on the execution, first you must call |
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| 424 | ///\ref lemon::Bfs::init() "init()", then you can add several source |
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| 425 | ///nodes with \ref lemon::Bfs::addSource() "addSource()". |
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| 426 | ///Finally \ref lemon::Bfs::start() "start()" will perform the |
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| 427 | ///actual path computation. |
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[100] | 428 | |
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| 429 | ///@{ |
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| 430 | |
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[244] | 431 | ///Initializes the internal data structures. |
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| 432 | |
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[100] | 433 | ///Initializes the internal data structures. |
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| 434 | /// |
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| 435 | void init() |
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| 436 | { |
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| 437 | create_maps(); |
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| 438 | _queue.resize(countNodes(*G)); |
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| 439 | _queue_head=_queue_tail=0; |
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| 440 | _curr_dist=1; |
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| 441 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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[209] | 442 | _pred->set(u,INVALID); |
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| 443 | _reached->set(u,false); |
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| 444 | _processed->set(u,false); |
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[100] | 445 | } |
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| 446 | } |
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[209] | 447 | |
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[100] | 448 | ///Adds a new source node. |
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| 449 | |
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| 450 | ///Adds a new source node to the set of nodes to be processed. |
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| 451 | /// |
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| 452 | void addSource(Node s) |
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| 453 | { |
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| 454 | if(!(*_reached)[s]) |
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[209] | 455 | { |
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| 456 | _reached->set(s,true); |
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| 457 | _pred->set(s,INVALID); |
---|
| 458 | _dist->set(s,0); |
---|
| 459 | _queue[_queue_head++]=s; |
---|
| 460 | _queue_next_dist=_queue_head; |
---|
| 461 | } |
---|
[100] | 462 | } |
---|
[209] | 463 | |
---|
[100] | 464 | ///Processes the next node. |
---|
| 465 | |
---|
| 466 | ///Processes the next node. |
---|
| 467 | /// |
---|
| 468 | ///\return The processed node. |
---|
| 469 | /// |
---|
[244] | 470 | ///\pre The queue must not be empty. |
---|
[100] | 471 | Node processNextNode() |
---|
| 472 | { |
---|
| 473 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 474 | _curr_dist++; |
---|
| 475 | _queue_next_dist=_queue_head; |
---|
[100] | 476 | } |
---|
| 477 | Node n=_queue[_queue_tail++]; |
---|
| 478 | _processed->set(n,true); |
---|
| 479 | Node m; |
---|
| 480 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 481 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 482 | _queue[_queue_head++]=m; |
---|
| 483 | _reached->set(m,true); |
---|
| 484 | _pred->set(m,e); |
---|
| 485 | _dist->set(m,_curr_dist); |
---|
| 486 | } |
---|
[100] | 487 | return n; |
---|
| 488 | } |
---|
| 489 | |
---|
| 490 | ///Processes the next node. |
---|
| 491 | |
---|
[244] | 492 | ///Processes the next node and checks if the given target node |
---|
[100] | 493 | ///is reached. If the target node is reachable from the processed |
---|
[244] | 494 | ///node, then the \c reach parameter will be set to \c true. |
---|
[100] | 495 | /// |
---|
| 496 | ///\param target The target node. |
---|
[244] | 497 | ///\retval reach Indicates if the target node is reached. |
---|
| 498 | ///It should be initially \c false. |
---|
| 499 | /// |
---|
[100] | 500 | ///\return The processed node. |
---|
| 501 | /// |
---|
[244] | 502 | ///\pre The queue must not be empty. |
---|
[100] | 503 | Node processNextNode(Node target, bool& reach) |
---|
| 504 | { |
---|
| 505 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 506 | _curr_dist++; |
---|
| 507 | _queue_next_dist=_queue_head; |
---|
[100] | 508 | } |
---|
| 509 | Node n=_queue[_queue_tail++]; |
---|
| 510 | _processed->set(n,true); |
---|
| 511 | Node m; |
---|
| 512 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 513 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 514 | _queue[_queue_head++]=m; |
---|
| 515 | _reached->set(m,true); |
---|
| 516 | _pred->set(m,e); |
---|
| 517 | _dist->set(m,_curr_dist); |
---|
[100] | 518 | reach = reach || (target == m); |
---|
[209] | 519 | } |
---|
[100] | 520 | return n; |
---|
| 521 | } |
---|
| 522 | |
---|
| 523 | ///Processes the next node. |
---|
| 524 | |
---|
[244] | 525 | ///Processes the next node and checks if at least one of reached |
---|
| 526 | ///nodes has \c true value in the \c nm node map. If one node |
---|
| 527 | ///with \c true value is reachable from the processed node, then the |
---|
| 528 | ///\c rnode parameter will be set to the first of such nodes. |
---|
[100] | 529 | /// |
---|
[244] | 530 | ///\param nm A \c bool (or convertible) node map that indicates the |
---|
| 531 | ///possible targets. |
---|
[100] | 532 | ///\retval rnode The reached target node. |
---|
[244] | 533 | ///It should be initially \c INVALID. |
---|
| 534 | /// |
---|
[100] | 535 | ///\return The processed node. |
---|
| 536 | /// |
---|
[244] | 537 | ///\pre The queue must not be empty. |
---|
[100] | 538 | template<class NM> |
---|
| 539 | Node processNextNode(const NM& nm, Node& rnode) |
---|
| 540 | { |
---|
| 541 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 542 | _curr_dist++; |
---|
| 543 | _queue_next_dist=_queue_head; |
---|
[100] | 544 | } |
---|
| 545 | Node n=_queue[_queue_tail++]; |
---|
| 546 | _processed->set(n,true); |
---|
| 547 | Node m; |
---|
| 548 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 549 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 550 | _queue[_queue_head++]=m; |
---|
| 551 | _reached->set(m,true); |
---|
| 552 | _pred->set(m,e); |
---|
| 553 | _dist->set(m,_curr_dist); |
---|
| 554 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 555 | } |
---|
[100] | 556 | return n; |
---|
| 557 | } |
---|
[209] | 558 | |
---|
[244] | 559 | ///The next node to be processed. |
---|
[100] | 560 | |
---|
[244] | 561 | ///Returns the next node to be processed or \c INVALID if the queue |
---|
| 562 | ///is empty. |
---|
| 563 | Node nextNode() const |
---|
[209] | 564 | { |
---|
[100] | 565 | return _queue_tail<_queue_head?_queue[_queue_tail]:INVALID; |
---|
| 566 | } |
---|
[209] | 567 | |
---|
[100] | 568 | ///\brief Returns \c false if there are nodes |
---|
[244] | 569 | ///to be processed. |
---|
[100] | 570 | /// |
---|
| 571 | ///Returns \c false if there are nodes |
---|
[244] | 572 | ///to be processed in the queue. |
---|
| 573 | bool emptyQueue() const { return _queue_tail==_queue_head; } |
---|
| 574 | |
---|
[100] | 575 | ///Returns the number of the nodes to be processed. |
---|
[209] | 576 | |
---|
[100] | 577 | ///Returns the number of the nodes to be processed in the queue. |
---|
[244] | 578 | int queueSize() const { return _queue_head-_queue_tail; } |
---|
[209] | 579 | |
---|
[100] | 580 | ///Executes the algorithm. |
---|
| 581 | |
---|
| 582 | ///Executes the algorithm. |
---|
| 583 | /// |
---|
[244] | 584 | ///This method runs the %BFS algorithm from the root node(s) |
---|
| 585 | ///in order to compute the shortest path to each node. |
---|
[100] | 586 | /// |
---|
[244] | 587 | ///The algorithm computes |
---|
| 588 | ///- the shortest path tree (forest), |
---|
| 589 | ///- the distance of each node from the root(s). |
---|
| 590 | /// |
---|
| 591 | ///\pre init() must be called and at least one root node should be |
---|
| 592 | ///added with addSource() before using this function. |
---|
| 593 | /// |
---|
| 594 | ///\note <tt>b.start()</tt> is just a shortcut of the following code. |
---|
| 595 | ///\code |
---|
| 596 | /// while ( !b.emptyQueue() ) { |
---|
| 597 | /// b.processNextNode(); |
---|
| 598 | /// } |
---|
| 599 | ///\endcode |
---|
[100] | 600 | void start() |
---|
| 601 | { |
---|
| 602 | while ( !emptyQueue() ) processNextNode(); |
---|
| 603 | } |
---|
[209] | 604 | |
---|
[244] | 605 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 606 | |
---|
[244] | 607 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 608 | /// |
---|
| 609 | ///This method runs the %BFS algorithm from the root node(s) |
---|
[286] | 610 | ///in order to compute the shortest path to \c t. |
---|
[244] | 611 | /// |
---|
[100] | 612 | ///The algorithm computes |
---|
[286] | 613 | ///- the shortest path to \c t, |
---|
| 614 | ///- the distance of \c t from the root(s). |
---|
[244] | 615 | /// |
---|
| 616 | ///\pre init() must be called and at least one root node should be |
---|
| 617 | ///added with addSource() before using this function. |
---|
| 618 | /// |
---|
| 619 | ///\note <tt>b.start(t)</tt> is just a shortcut of the following code. |
---|
| 620 | ///\code |
---|
| 621 | /// bool reach = false; |
---|
| 622 | /// while ( !b.emptyQueue() && !reach ) { |
---|
| 623 | /// b.processNextNode(t, reach); |
---|
| 624 | /// } |
---|
| 625 | ///\endcode |
---|
[286] | 626 | void start(Node t) |
---|
[100] | 627 | { |
---|
| 628 | bool reach = false; |
---|
[286] | 629 | while ( !emptyQueue() && !reach ) processNextNode(t, reach); |
---|
[100] | 630 | } |
---|
[209] | 631 | |
---|
[100] | 632 | ///Executes the algorithm until a condition is met. |
---|
| 633 | |
---|
| 634 | ///Executes the algorithm until a condition is met. |
---|
| 635 | /// |
---|
[244] | 636 | ///This method runs the %BFS algorithm from the root node(s) in |
---|
| 637 | ///order to compute the shortest path to a node \c v with |
---|
| 638 | /// <tt>nm[v]</tt> true, if such a node can be found. |
---|
[100] | 639 | /// |
---|
[244] | 640 | ///\param nm A \c bool (or convertible) node map. The algorithm |
---|
| 641 | ///will stop when it reaches a node \c v with <tt>nm[v]</tt> true. |
---|
[100] | 642 | /// |
---|
| 643 | ///\return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 644 | ///\c INVALID if no such node was found. |
---|
[244] | 645 | /// |
---|
| 646 | ///\pre init() must be called and at least one root node should be |
---|
| 647 | ///added with addSource() before using this function. |
---|
| 648 | /// |
---|
| 649 | ///\note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
---|
| 650 | ///\code |
---|
| 651 | /// Node rnode = INVALID; |
---|
| 652 | /// while ( !b.emptyQueue() && rnode == INVALID ) { |
---|
| 653 | /// b.processNextNode(nm, rnode); |
---|
| 654 | /// } |
---|
| 655 | /// return rnode; |
---|
| 656 | ///\endcode |
---|
| 657 | template<class NodeBoolMap> |
---|
| 658 | Node start(const NodeBoolMap &nm) |
---|
[100] | 659 | { |
---|
| 660 | Node rnode = INVALID; |
---|
| 661 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 662 | processNextNode(nm, rnode); |
---|
[100] | 663 | } |
---|
| 664 | return rnode; |
---|
| 665 | } |
---|
[209] | 666 | |
---|
[286] | 667 | ///Runs the algorithm from the given source node. |
---|
[209] | 668 | |
---|
[244] | 669 | ///This method runs the %BFS algorithm from node \c s |
---|
| 670 | ///in order to compute the shortest path to each node. |
---|
[100] | 671 | /// |
---|
[244] | 672 | ///The algorithm computes |
---|
| 673 | ///- the shortest path tree, |
---|
| 674 | ///- the distance of each node from the root. |
---|
| 675 | /// |
---|
| 676 | ///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 677 | ///\code |
---|
| 678 | /// b.init(); |
---|
| 679 | /// b.addSource(s); |
---|
| 680 | /// b.start(); |
---|
| 681 | ///\endcode |
---|
| 682 | void run(Node s) { |
---|
| 683 | init(); |
---|
| 684 | addSource(s); |
---|
| 685 | start(); |
---|
| 686 | } |
---|
[209] | 687 | |
---|
[100] | 688 | ///Finds the shortest path between \c s and \c t. |
---|
[209] | 689 | |
---|
[244] | 690 | ///This method runs the %BFS algorithm from node \c s |
---|
[286] | 691 | ///in order to compute the shortest path to node \c t |
---|
| 692 | ///(it stops searching when \c t is processed). |
---|
[100] | 693 | /// |
---|
[286] | 694 | ///\return \c true if \c t is reachable form \c s. |
---|
[244] | 695 | /// |
---|
| 696 | ///\note Apart from the return value, <tt>b.run(s,t)</tt> is just a |
---|
| 697 | ///shortcut of the following code. |
---|
[100] | 698 | ///\code |
---|
| 699 | /// b.init(); |
---|
| 700 | /// b.addSource(s); |
---|
| 701 | /// b.start(t); |
---|
| 702 | ///\endcode |
---|
[286] | 703 | bool run(Node s,Node t) { |
---|
[100] | 704 | init(); |
---|
| 705 | addSource(s); |
---|
| 706 | start(t); |
---|
[286] | 707 | return reached(t); |
---|
[100] | 708 | } |
---|
[209] | 709 | |
---|
[244] | 710 | ///Runs the algorithm to visit all nodes in the digraph. |
---|
| 711 | |
---|
| 712 | ///This method runs the %BFS algorithm in order to |
---|
| 713 | ///compute the shortest path to each node. |
---|
| 714 | /// |
---|
| 715 | ///The algorithm computes |
---|
| 716 | ///- the shortest path tree (forest), |
---|
| 717 | ///- the distance of each node from the root(s). |
---|
| 718 | /// |
---|
| 719 | ///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
| 720 | ///\code |
---|
| 721 | /// b.init(); |
---|
| 722 | /// for (NodeIt n(gr); n != INVALID; ++n) { |
---|
| 723 | /// if (!b.reached(n)) { |
---|
| 724 | /// b.addSource(n); |
---|
| 725 | /// b.start(); |
---|
| 726 | /// } |
---|
| 727 | /// } |
---|
| 728 | ///\endcode |
---|
| 729 | void run() { |
---|
| 730 | init(); |
---|
| 731 | for (NodeIt n(*G); n != INVALID; ++n) { |
---|
| 732 | if (!reached(n)) { |
---|
| 733 | addSource(n); |
---|
| 734 | start(); |
---|
| 735 | } |
---|
| 736 | } |
---|
| 737 | } |
---|
| 738 | |
---|
[100] | 739 | ///@} |
---|
| 740 | |
---|
| 741 | ///\name Query Functions |
---|
| 742 | ///The result of the %BFS algorithm can be obtained using these |
---|
| 743 | ///functions.\n |
---|
[244] | 744 | ///Either \ref lemon::Bfs::run() "run()" or \ref lemon::Bfs::start() |
---|
| 745 | ///"start()" must be called before using them. |
---|
[209] | 746 | |
---|
[100] | 747 | ///@{ |
---|
| 748 | |
---|
[244] | 749 | ///The shortest path to a node. |
---|
[100] | 750 | |
---|
[244] | 751 | ///Returns the shortest path to a node. |
---|
| 752 | /// |
---|
| 753 | ///\warning \c t should be reachable from the root(s). |
---|
| 754 | /// |
---|
| 755 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 756 | ///using this function. |
---|
| 757 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
[100] | 758 | |
---|
| 759 | ///The distance of a node from the root(s). |
---|
| 760 | |
---|
| 761 | ///Returns the distance of a node from the root(s). |
---|
[244] | 762 | /// |
---|
| 763 | ///\warning If node \c v is not reachable from the root(s), then |
---|
| 764 | ///the return value of this function is undefined. |
---|
| 765 | /// |
---|
| 766 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 767 | ///using this function. |
---|
[100] | 768 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 769 | |
---|
[244] | 770 | ///Returns the 'previous arc' of the shortest path tree for a node. |
---|
[100] | 771 | |
---|
[244] | 772 | ///This function returns the 'previous arc' of the shortest path |
---|
| 773 | ///tree for the node \c v, i.e. it returns the last arc of a |
---|
| 774 | ///shortest path from the root(s) to \c v. It is \c INVALID if \c v |
---|
| 775 | ///is not reachable from the root(s) or if \c v is a root. |
---|
| 776 | /// |
---|
| 777 | ///The shortest path tree used here is equal to the shortest path |
---|
| 778 | ///tree used in \ref predNode(). |
---|
| 779 | /// |
---|
| 780 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 781 | ///using this function. |
---|
[100] | 782 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 783 | |
---|
[244] | 784 | ///Returns the 'previous node' of the shortest path tree for a node. |
---|
[100] | 785 | |
---|
[244] | 786 | ///This function returns the 'previous node' of the shortest path |
---|
| 787 | ///tree for the node \c v, i.e. it returns the last but one node |
---|
| 788 | ///from a shortest path from the root(s) to \c v. It is \c INVALID |
---|
| 789 | ///if \c v is not reachable from the root(s) or if \c v is a root. |
---|
| 790 | /// |
---|
[100] | 791 | ///The shortest path tree used here is equal to the shortest path |
---|
| 792 | ///tree used in \ref predArc(). |
---|
[244] | 793 | /// |
---|
[100] | 794 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 795 | ///using this function. |
---|
| 796 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
[209] | 797 | G->source((*_pred)[v]); } |
---|
| 798 | |
---|
[244] | 799 | ///\brief Returns a const reference to the node map that stores the |
---|
| 800 | /// distances of the nodes. |
---|
| 801 | /// |
---|
| 802 | ///Returns a const reference to the node map that stores the distances |
---|
| 803 | ///of the nodes calculated by the algorithm. |
---|
| 804 | /// |
---|
| 805 | ///\pre Either \ref run() or \ref init() |
---|
| 806 | ///must be called before using this function. |
---|
[100] | 807 | const DistMap &distMap() const { return *_dist;} |
---|
[209] | 808 | |
---|
[244] | 809 | ///\brief Returns a const reference to the node map that stores the |
---|
| 810 | ///predecessor arcs. |
---|
| 811 | /// |
---|
| 812 | ///Returns a const reference to the node map that stores the predecessor |
---|
| 813 | ///arcs, which form the shortest path tree. |
---|
| 814 | /// |
---|
[100] | 815 | ///\pre Either \ref run() or \ref init() |
---|
| 816 | ///must be called before using this function. |
---|
| 817 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 818 | |
---|
[244] | 819 | ///Checks if a node is reachable from the root(s). |
---|
[100] | 820 | |
---|
[244] | 821 | ///Returns \c true if \c v is reachable from the root(s). |
---|
[100] | 822 | ///\pre Either \ref run() or \ref start() |
---|
| 823 | ///must be called before using this function. |
---|
[244] | 824 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[209] | 825 | |
---|
[100] | 826 | ///@} |
---|
| 827 | }; |
---|
| 828 | |
---|
[244] | 829 | ///Default traits class of bfs() function. |
---|
[100] | 830 | |
---|
[244] | 831 | ///Default traits class of bfs() function. |
---|
[157] | 832 | ///\tparam GR Digraph type. |
---|
[100] | 833 | template<class GR> |
---|
| 834 | struct BfsWizardDefaultTraits |
---|
| 835 | { |
---|
[244] | 836 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 837 | typedef GR Digraph; |
---|
[244] | 838 | |
---|
| 839 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 840 | ///arcs of the shortest paths. |
---|
[209] | 841 | /// |
---|
[244] | 842 | ///The type of the map that stores the predecessor |
---|
[100] | 843 | ///arcs of the shortest paths. |
---|
| 844 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 845 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
---|
[244] | 846 | ///Instantiates a \ref PredMap. |
---|
[209] | 847 | |
---|
| 848 | ///This function instantiates a \ref PredMap. |
---|
[244] | 849 | ///\param g is the digraph, to which we would like to define the |
---|
| 850 | ///\ref PredMap. |
---|
[100] | 851 | ///\todo The digraph alone may be insufficient to initialize |
---|
[244] | 852 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 853 | { |
---|
[278] | 854 | return new PredMap(g); |
---|
[100] | 855 | } |
---|
| 856 | |
---|
| 857 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 858 | |
---|
[100] | 859 | ///The type of the map that indicates which nodes are processed. |
---|
| 860 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 861 | ///By default it is a NullMap. |
---|
[100] | 862 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[244] | 863 | ///Instantiates a \ref ProcessedMap. |
---|
[209] | 864 | |
---|
| 865 | ///This function instantiates a \ref ProcessedMap. |
---|
[100] | 866 | ///\param g is the digraph, to which |
---|
[244] | 867 | ///we would like to define the \ref ProcessedMap. |
---|
[100] | 868 | #ifdef DOXYGEN |
---|
[244] | 869 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 870 | #else |
---|
[244] | 871 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 872 | #endif |
---|
| 873 | { |
---|
| 874 | return new ProcessedMap(); |
---|
| 875 | } |
---|
[244] | 876 | |
---|
[100] | 877 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 878 | |
---|
[100] | 879 | ///The type of the map that indicates which nodes are reached. |
---|
[244] | 880 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 881 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[244] | 882 | ///Instantiates a \ref ReachedMap. |
---|
[209] | 883 | |
---|
| 884 | ///This function instantiates a \ref ReachedMap. |
---|
[244] | 885 | ///\param g is the digraph, to which |
---|
[100] | 886 | ///we would like to define the \ref ReachedMap. |
---|
[244] | 887 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 888 | { |
---|
[244] | 889 | return new ReachedMap(g); |
---|
[100] | 890 | } |
---|
[209] | 891 | |
---|
[244] | 892 | ///The type of the map that stores the distances of the nodes. |
---|
| 893 | |
---|
| 894 | ///The type of the map that stores the distances of the nodes. |
---|
[100] | 895 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 896 | typedef typename Digraph::template NodeMap<int> DistMap; |
---|
[244] | 897 | ///Instantiates a \ref DistMap. |
---|
[209] | 898 | |
---|
| 899 | ///This function instantiates a \ref DistMap. |
---|
[210] | 900 | ///\param g is the digraph, to which we would like to define |
---|
| 901 | ///the \ref DistMap |
---|
[244] | 902 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 903 | { |
---|
[278] | 904 | return new DistMap(g); |
---|
[100] | 905 | } |
---|
[278] | 906 | |
---|
| 907 | ///The type of the shortest paths. |
---|
| 908 | |
---|
| 909 | ///The type of the shortest paths. |
---|
| 910 | ///It must meet the \ref concepts::Path "Path" concept. |
---|
| 911 | typedef lemon::Path<Digraph> Path; |
---|
[100] | 912 | }; |
---|
[209] | 913 | |
---|
[244] | 914 | /// Default traits class used by \ref BfsWizard |
---|
[100] | 915 | |
---|
| 916 | /// To make it easier to use Bfs algorithm |
---|
[244] | 917 | /// we have created a wizard class. |
---|
[100] | 918 | /// This \ref BfsWizard class needs default traits, |
---|
[244] | 919 | /// as well as the \ref Bfs class. |
---|
[100] | 920 | /// The \ref BfsWizardBase is a class to be the default traits of the |
---|
| 921 | /// \ref BfsWizard class. |
---|
| 922 | template<class GR> |
---|
| 923 | class BfsWizardBase : public BfsWizardDefaultTraits<GR> |
---|
| 924 | { |
---|
| 925 | |
---|
| 926 | typedef BfsWizardDefaultTraits<GR> Base; |
---|
| 927 | protected: |
---|
[244] | 928 | //The type of the nodes in the digraph. |
---|
[100] | 929 | typedef typename Base::Digraph::Node Node; |
---|
| 930 | |
---|
[244] | 931 | //Pointer to the digraph the algorithm runs on. |
---|
[100] | 932 | void *_g; |
---|
[244] | 933 | //Pointer to the map of reached nodes. |
---|
[100] | 934 | void *_reached; |
---|
[244] | 935 | //Pointer to the map of processed nodes. |
---|
[100] | 936 | void *_processed; |
---|
[244] | 937 | //Pointer to the map of predecessors arcs. |
---|
[100] | 938 | void *_pred; |
---|
[244] | 939 | //Pointer to the map of distances. |
---|
[100] | 940 | void *_dist; |
---|
[278] | 941 | //Pointer to the shortest path to the target node. |
---|
| 942 | void *_path; |
---|
| 943 | //Pointer to the distance of the target node. |
---|
| 944 | int *_di; |
---|
[209] | 945 | |
---|
[100] | 946 | public: |
---|
| 947 | /// Constructor. |
---|
[209] | 948 | |
---|
[100] | 949 | /// This constructor does not require parameters, therefore it initiates |
---|
[278] | 950 | /// all of the attributes to \c 0. |
---|
[100] | 951 | BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[278] | 952 | _dist(0), _path(0), _di(0) {} |
---|
[100] | 953 | |
---|
| 954 | /// Constructor. |
---|
[209] | 955 | |
---|
[278] | 956 | /// This constructor requires one parameter, |
---|
| 957 | /// others are initiated to \c 0. |
---|
[244] | 958 | /// \param g The digraph the algorithm runs on. |
---|
[278] | 959 | BfsWizardBase(const GR &g) : |
---|
[209] | 960 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
---|
[278] | 961 | _reached(0), _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
---|
[100] | 962 | |
---|
| 963 | }; |
---|
[209] | 964 | |
---|
[278] | 965 | /// Auxiliary class for the function-type interface of BFS algorithm. |
---|
[100] | 966 | |
---|
[278] | 967 | /// This auxiliary class is created to implement the |
---|
| 968 | /// \ref bfs() "function-type interface" of \ref Bfs algorithm. |
---|
| 969 | /// It does not have own \ref run() method, it uses the functions |
---|
| 970 | /// and features of the plain \ref Bfs. |
---|
[100] | 971 | /// |
---|
[278] | 972 | /// This class should only be used through the \ref bfs() function, |
---|
| 973 | /// which makes it easier to use the algorithm. |
---|
[100] | 974 | template<class TR> |
---|
| 975 | class BfsWizard : public TR |
---|
| 976 | { |
---|
| 977 | typedef TR Base; |
---|
| 978 | |
---|
[244] | 979 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 980 | typedef typename TR::Digraph Digraph; |
---|
[244] | 981 | |
---|
[100] | 982 | typedef typename Digraph::Node Node; |
---|
| 983 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 984 | typedef typename Digraph::Arc Arc; |
---|
| 985 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
[209] | 986 | |
---|
[244] | 987 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 988 | ///arcs of the shortest paths. |
---|
| 989 | typedef typename TR::PredMap PredMap; |
---|
[244] | 990 | ///\brief The type of the map that stores the distances of the nodes. |
---|
[100] | 991 | typedef typename TR::DistMap DistMap; |
---|
[244] | 992 | ///\brief The type of the map that indicates which nodes are reached. |
---|
| 993 | typedef typename TR::ReachedMap ReachedMap; |
---|
| 994 | ///\brief The type of the map that indicates which nodes are processed. |
---|
| 995 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
[278] | 996 | ///The type of the shortest paths |
---|
| 997 | typedef typename TR::Path Path; |
---|
[100] | 998 | |
---|
| 999 | public: |
---|
[244] | 1000 | |
---|
[100] | 1001 | /// Constructor. |
---|
| 1002 | BfsWizard() : TR() {} |
---|
| 1003 | |
---|
| 1004 | /// Constructor that requires parameters. |
---|
| 1005 | |
---|
| 1006 | /// Constructor that requires parameters. |
---|
| 1007 | /// These parameters will be the default values for the traits class. |
---|
[278] | 1008 | /// \param g The digraph the algorithm runs on. |
---|
| 1009 | BfsWizard(const Digraph &g) : |
---|
| 1010 | TR(g) {} |
---|
[100] | 1011 | |
---|
| 1012 | ///Copy constructor |
---|
| 1013 | BfsWizard(const TR &b) : TR(b) {} |
---|
| 1014 | |
---|
| 1015 | ~BfsWizard() {} |
---|
| 1016 | |
---|
[278] | 1017 | ///Runs BFS algorithm from the given source node. |
---|
[209] | 1018 | |
---|
[278] | 1019 | ///This method runs BFS algorithm from node \c s |
---|
| 1020 | ///in order to compute the shortest path to each node. |
---|
| 1021 | void run(Node s) |
---|
| 1022 | { |
---|
| 1023 | Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 1024 | if (Base::_pred) |
---|
| 1025 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 1026 | if (Base::_dist) |
---|
| 1027 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 1028 | if (Base::_reached) |
---|
| 1029 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 1030 | if (Base::_processed) |
---|
| 1031 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 1032 | if (s!=INVALID) |
---|
| 1033 | alg.run(s); |
---|
| 1034 | else |
---|
| 1035 | alg.run(); |
---|
| 1036 | } |
---|
| 1037 | |
---|
| 1038 | ///Finds the shortest path between \c s and \c t. |
---|
| 1039 | |
---|
| 1040 | ///This method runs BFS algorithm from node \c s |
---|
| 1041 | ///in order to compute the shortest path to node \c t |
---|
| 1042 | ///(it stops searching when \c t is processed). |
---|
| 1043 | /// |
---|
| 1044 | ///\return \c true if \c t is reachable form \c s. |
---|
| 1045 | bool run(Node s, Node t) |
---|
| 1046 | { |
---|
| 1047 | if (s==INVALID || t==INVALID) throw UninitializedParameter(); |
---|
| 1048 | Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 1049 | if (Base::_pred) |
---|
| 1050 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 1051 | if (Base::_dist) |
---|
| 1052 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 1053 | if (Base::_reached) |
---|
| 1054 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 1055 | if (Base::_processed) |
---|
| 1056 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 1057 | alg.run(s,t); |
---|
| 1058 | if (Base::_path) |
---|
| 1059 | *reinterpret_cast<Path*>(Base::_path) = alg.path(t); |
---|
| 1060 | if (Base::_di) |
---|
| 1061 | *Base::_di = alg.dist(t); |
---|
| 1062 | return alg.reached(t); |
---|
| 1063 | } |
---|
| 1064 | |
---|
| 1065 | ///Runs BFS algorithm to visit all nodes in the digraph. |
---|
| 1066 | |
---|
| 1067 | ///This method runs BFS algorithm in order to compute |
---|
| 1068 | ///the shortest path to each node. |
---|
[100] | 1069 | void run() |
---|
| 1070 | { |
---|
[278] | 1071 | run(INVALID); |
---|
[100] | 1072 | } |
---|
[209] | 1073 | |
---|
[244] | 1074 | template<class T> |
---|
[257] | 1075 | struct SetPredMapBase : public Base { |
---|
[244] | 1076 | typedef T PredMap; |
---|
| 1077 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
[257] | 1078 | SetPredMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1079 | }; |
---|
[278] | 1080 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1081 | ///for setting \ref PredMap object. |
---|
| 1082 | /// |
---|
[278] | 1083 | ///\ref named-func-param "Named parameter" |
---|
[244] | 1084 | ///for setting \ref PredMap object. |
---|
| 1085 | template<class T> |
---|
[257] | 1086 | BfsWizard<SetPredMapBase<T> > predMap(const T &t) |
---|
[244] | 1087 | { |
---|
| 1088 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1089 | return BfsWizard<SetPredMapBase<T> >(*this); |
---|
[244] | 1090 | } |
---|
| 1091 | |
---|
| 1092 | template<class T> |
---|
[257] | 1093 | struct SetReachedMapBase : public Base { |
---|
[244] | 1094 | typedef T ReachedMap; |
---|
| 1095 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
[257] | 1096 | SetReachedMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1097 | }; |
---|
[278] | 1098 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1099 | ///for setting \ref ReachedMap object. |
---|
| 1100 | /// |
---|
[278] | 1101 | /// \ref named-func-param "Named parameter" |
---|
[244] | 1102 | ///for setting \ref ReachedMap object. |
---|
| 1103 | template<class T> |
---|
[257] | 1104 | BfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
---|
[244] | 1105 | { |
---|
| 1106 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1107 | return BfsWizard<SetReachedMapBase<T> >(*this); |
---|
[244] | 1108 | } |
---|
| 1109 | |
---|
| 1110 | template<class T> |
---|
[278] | 1111 | struct SetDistMapBase : public Base { |
---|
| 1112 | typedef T DistMap; |
---|
| 1113 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
| 1114 | SetDistMapBase(const TR &b) : TR(b) {} |
---|
| 1115 | }; |
---|
| 1116 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1117 | ///for setting \ref DistMap object. |
---|
| 1118 | /// |
---|
| 1119 | /// \ref named-func-param "Named parameter" |
---|
| 1120 | ///for setting \ref DistMap object. |
---|
| 1121 | template<class T> |
---|
| 1122 | BfsWizard<SetDistMapBase<T> > distMap(const T &t) |
---|
| 1123 | { |
---|
| 1124 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1125 | return BfsWizard<SetDistMapBase<T> >(*this); |
---|
| 1126 | } |
---|
| 1127 | |
---|
| 1128 | template<class T> |
---|
[257] | 1129 | struct SetProcessedMapBase : public Base { |
---|
[244] | 1130 | typedef T ProcessedMap; |
---|
| 1131 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
[257] | 1132 | SetProcessedMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1133 | }; |
---|
[278] | 1134 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1135 | ///for setting \ref ProcessedMap object. |
---|
| 1136 | /// |
---|
[278] | 1137 | /// \ref named-func-param "Named parameter" |
---|
[244] | 1138 | ///for setting \ref ProcessedMap object. |
---|
| 1139 | template<class T> |
---|
[257] | 1140 | BfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
---|
[244] | 1141 | { |
---|
| 1142 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1143 | return BfsWizard<SetProcessedMapBase<T> >(*this); |
---|
[244] | 1144 | } |
---|
| 1145 | |
---|
| 1146 | template<class T> |
---|
[278] | 1147 | struct SetPathBase : public Base { |
---|
| 1148 | typedef T Path; |
---|
| 1149 | SetPathBase(const TR &b) : TR(b) {} |
---|
[244] | 1150 | }; |
---|
[278] | 1151 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1152 | ///for getting the shortest path to the target node. |
---|
[244] | 1153 | /// |
---|
[278] | 1154 | ///\ref named-func-param "Named parameter" |
---|
| 1155 | ///for getting the shortest path to the target node. |
---|
[244] | 1156 | template<class T> |
---|
[278] | 1157 | BfsWizard<SetPathBase<T> > path(const T &t) |
---|
[244] | 1158 | { |
---|
[278] | 1159 | Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1160 | return BfsWizard<SetPathBase<T> >(*this); |
---|
| 1161 | } |
---|
| 1162 | |
---|
| 1163 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1164 | ///for getting the distance of the target node. |
---|
| 1165 | /// |
---|
| 1166 | ///\ref named-func-param "Named parameter" |
---|
| 1167 | ///for getting the distance of the target node. |
---|
| 1168 | BfsWizard dist(const int &d) |
---|
| 1169 | { |
---|
| 1170 | Base::_di=const_cast<int*>(&d); |
---|
| 1171 | return *this; |
---|
[244] | 1172 | } |
---|
| 1173 | |
---|
[100] | 1174 | }; |
---|
[209] | 1175 | |
---|
[278] | 1176 | ///Function-type interface for BFS algorithm. |
---|
[100] | 1177 | |
---|
| 1178 | /// \ingroup search |
---|
[278] | 1179 | ///Function-type interface for BFS algorithm. |
---|
[100] | 1180 | /// |
---|
[278] | 1181 | ///This function also has several \ref named-func-param "named parameters", |
---|
[100] | 1182 | ///they are declared as the members of class \ref BfsWizard. |
---|
[278] | 1183 | ///The following examples show how to use these parameters. |
---|
[100] | 1184 | ///\code |
---|
[278] | 1185 | /// // Compute shortest path from node s to each node |
---|
| 1186 | /// bfs(g).predMap(preds).distMap(dists).run(s); |
---|
| 1187 | /// |
---|
| 1188 | /// // Compute shortest path from s to t |
---|
| 1189 | /// bool reached = bfs(g).path(p).dist(d).run(s,t); |
---|
[100] | 1190 | ///\endcode |
---|
| 1191 | ///\warning Don't forget to put the \ref BfsWizard::run() "run()" |
---|
| 1192 | ///to the end of the parameter list. |
---|
| 1193 | ///\sa BfsWizard |
---|
| 1194 | ///\sa Bfs |
---|
| 1195 | template<class GR> |
---|
| 1196 | BfsWizard<BfsWizardBase<GR> > |
---|
[278] | 1197 | bfs(const GR &digraph) |
---|
[100] | 1198 | { |
---|
[278] | 1199 | return BfsWizard<BfsWizardBase<GR> >(digraph); |
---|
[100] | 1200 | } |
---|
| 1201 | |
---|
| 1202 | #ifdef DOXYGEN |
---|
[244] | 1203 | /// \brief Visitor class for BFS. |
---|
[209] | 1204 | /// |
---|
[100] | 1205 | /// This class defines the interface of the BfsVisit events, and |
---|
[244] | 1206 | /// it could be the base of a real visitor class. |
---|
[100] | 1207 | template <typename _Digraph> |
---|
| 1208 | struct BfsVisitor { |
---|
| 1209 | typedef _Digraph Digraph; |
---|
| 1210 | typedef typename Digraph::Arc Arc; |
---|
| 1211 | typedef typename Digraph::Node Node; |
---|
[244] | 1212 | /// \brief Called for the source node(s) of the BFS. |
---|
[209] | 1213 | /// |
---|
[244] | 1214 | /// This function is called for the source node(s) of the BFS. |
---|
| 1215 | void start(const Node& node) {} |
---|
| 1216 | /// \brief Called when a node is reached first time. |
---|
| 1217 | /// |
---|
| 1218 | /// This function is called when a node is reached first time. |
---|
| 1219 | void reach(const Node& node) {} |
---|
| 1220 | /// \brief Called when a node is processed. |
---|
| 1221 | /// |
---|
| 1222 | /// This function is called when a node is processed. |
---|
| 1223 | void process(const Node& node) {} |
---|
| 1224 | /// \brief Called when an arc reaches a new node. |
---|
| 1225 | /// |
---|
| 1226 | /// This function is called when the BFS finds an arc whose target node |
---|
| 1227 | /// is not reached yet. |
---|
[100] | 1228 | void discover(const Arc& arc) {} |
---|
[244] | 1229 | /// \brief Called when an arc is examined but its target node is |
---|
[100] | 1230 | /// already discovered. |
---|
[209] | 1231 | /// |
---|
[244] | 1232 | /// This function is called when an arc is examined but its target node is |
---|
[100] | 1233 | /// already discovered. |
---|
| 1234 | void examine(const Arc& arc) {} |
---|
| 1235 | }; |
---|
| 1236 | #else |
---|
| 1237 | template <typename _Digraph> |
---|
| 1238 | struct BfsVisitor { |
---|
| 1239 | typedef _Digraph Digraph; |
---|
| 1240 | typedef typename Digraph::Arc Arc; |
---|
| 1241 | typedef typename Digraph::Node Node; |
---|
[244] | 1242 | void start(const Node&) {} |
---|
| 1243 | void reach(const Node&) {} |
---|
| 1244 | void process(const Node&) {} |
---|
[100] | 1245 | void discover(const Arc&) {} |
---|
| 1246 | void examine(const Arc&) {} |
---|
| 1247 | |
---|
| 1248 | template <typename _Visitor> |
---|
| 1249 | struct Constraints { |
---|
| 1250 | void constraints() { |
---|
[209] | 1251 | Arc arc; |
---|
| 1252 | Node node; |
---|
[244] | 1253 | visitor.start(node); |
---|
| 1254 | visitor.reach(node); |
---|
| 1255 | visitor.process(node); |
---|
[209] | 1256 | visitor.discover(arc); |
---|
| 1257 | visitor.examine(arc); |
---|
[100] | 1258 | } |
---|
| 1259 | _Visitor& visitor; |
---|
| 1260 | }; |
---|
| 1261 | }; |
---|
| 1262 | #endif |
---|
| 1263 | |
---|
| 1264 | /// \brief Default traits class of BfsVisit class. |
---|
| 1265 | /// |
---|
| 1266 | /// Default traits class of BfsVisit class. |
---|
[244] | 1267 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[100] | 1268 | template<class _Digraph> |
---|
| 1269 | struct BfsVisitDefaultTraits { |
---|
| 1270 | |
---|
[244] | 1271 | /// \brief The type of the digraph the algorithm runs on. |
---|
[100] | 1272 | typedef _Digraph Digraph; |
---|
| 1273 | |
---|
| 1274 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1275 | /// |
---|
[100] | 1276 | /// The type of the map that indicates which nodes are reached. |
---|
[244] | 1277 | /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 1278 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1279 | |
---|
[244] | 1280 | /// \brief Instantiates a \ref ReachedMap. |
---|
[100] | 1281 | /// |
---|
[209] | 1282 | /// This function instantiates a \ref ReachedMap. |
---|
[100] | 1283 | /// \param digraph is the digraph, to which |
---|
| 1284 | /// we would like to define the \ref ReachedMap. |
---|
| 1285 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1286 | return new ReachedMap(digraph); |
---|
| 1287 | } |
---|
| 1288 | |
---|
| 1289 | }; |
---|
| 1290 | |
---|
| 1291 | /// \ingroup search |
---|
[209] | 1292 | /// |
---|
[244] | 1293 | /// \brief %BFS algorithm class with visitor interface. |
---|
[209] | 1294 | /// |
---|
[100] | 1295 | /// This class provides an efficient implementation of the %BFS algorithm |
---|
| 1296 | /// with visitor interface. |
---|
| 1297 | /// |
---|
| 1298 | /// The %BfsVisit class provides an alternative interface to the Bfs |
---|
| 1299 | /// class. It works with callback mechanism, the BfsVisit object calls |
---|
[244] | 1300 | /// the member functions of the \c Visitor class on every BFS event. |
---|
[100] | 1301 | /// |
---|
[252] | 1302 | /// This interface of the BFS algorithm should be used in special cases |
---|
| 1303 | /// when extra actions have to be performed in connection with certain |
---|
| 1304 | /// events of the BFS algorithm. Otherwise consider to use Bfs or bfs() |
---|
| 1305 | /// instead. |
---|
| 1306 | /// |
---|
[244] | 1307 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[210] | 1308 | /// The default value is |
---|
[244] | 1309 | /// \ref ListDigraph. The value of _Digraph is not used directly by |
---|
| 1310 | /// \ref BfsVisit, it is only passed to \ref BfsVisitDefaultTraits. |
---|
| 1311 | /// \tparam _Visitor The Visitor type that is used by the algorithm. |
---|
| 1312 | /// \ref BfsVisitor "BfsVisitor<_Digraph>" is an empty visitor, which |
---|
| 1313 | /// does not observe the BFS events. If you want to observe the BFS |
---|
| 1314 | /// events, you should implement your own visitor class. |
---|
[209] | 1315 | /// \tparam _Traits Traits class to set various data types used by the |
---|
[100] | 1316 | /// algorithm. The default traits class is |
---|
| 1317 | /// \ref BfsVisitDefaultTraits "BfsVisitDefaultTraits<_Digraph>". |
---|
| 1318 | /// See \ref BfsVisitDefaultTraits for the documentation of |
---|
[244] | 1319 | /// a BFS visit traits class. |
---|
[100] | 1320 | #ifdef DOXYGEN |
---|
| 1321 | template <typename _Digraph, typename _Visitor, typename _Traits> |
---|
| 1322 | #else |
---|
| 1323 | template <typename _Digraph = ListDigraph, |
---|
[209] | 1324 | typename _Visitor = BfsVisitor<_Digraph>, |
---|
| 1325 | typename _Traits = BfsDefaultTraits<_Digraph> > |
---|
[100] | 1326 | #endif |
---|
| 1327 | class BfsVisit { |
---|
| 1328 | public: |
---|
[209] | 1329 | |
---|
[100] | 1330 | /// \brief \ref Exception for uninitialized parameters. |
---|
| 1331 | /// |
---|
| 1332 | /// This error represents problems in the initialization |
---|
[244] | 1333 | /// of the parameters of the algorithm. |
---|
[100] | 1334 | class UninitializedParameter : public lemon::UninitializedParameter { |
---|
| 1335 | public: |
---|
[209] | 1336 | virtual const char* what() const throw() |
---|
[100] | 1337 | { |
---|
[209] | 1338 | return "lemon::BfsVisit::UninitializedParameter"; |
---|
[100] | 1339 | } |
---|
| 1340 | }; |
---|
| 1341 | |
---|
[244] | 1342 | ///The traits class. |
---|
[100] | 1343 | typedef _Traits Traits; |
---|
| 1344 | |
---|
[244] | 1345 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 1346 | typedef typename Traits::Digraph Digraph; |
---|
| 1347 | |
---|
[244] | 1348 | ///The visitor type used by the algorithm. |
---|
[100] | 1349 | typedef _Visitor Visitor; |
---|
| 1350 | |
---|
[244] | 1351 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 1352 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1353 | |
---|
| 1354 | private: |
---|
| 1355 | |
---|
| 1356 | typedef typename Digraph::Node Node; |
---|
| 1357 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1358 | typedef typename Digraph::Arc Arc; |
---|
| 1359 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1360 | |
---|
[244] | 1361 | //Pointer to the underlying digraph. |
---|
[100] | 1362 | const Digraph *_digraph; |
---|
[244] | 1363 | //Pointer to the visitor object. |
---|
[100] | 1364 | Visitor *_visitor; |
---|
[244] | 1365 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 1366 | ReachedMap *_reached; |
---|
[244] | 1367 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 1368 | bool local_reached; |
---|
| 1369 | |
---|
| 1370 | std::vector<typename Digraph::Node> _list; |
---|
| 1371 | int _list_front, _list_back; |
---|
| 1372 | |
---|
[244] | 1373 | ///Creates the maps if necessary. |
---|
| 1374 | ///\todo Better memory allocation (instead of new). |
---|
[100] | 1375 | void create_maps() { |
---|
| 1376 | if(!_reached) { |
---|
[209] | 1377 | local_reached = true; |
---|
| 1378 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1379 | } |
---|
| 1380 | } |
---|
| 1381 | |
---|
| 1382 | protected: |
---|
| 1383 | |
---|
| 1384 | BfsVisit() {} |
---|
[209] | 1385 | |
---|
[100] | 1386 | public: |
---|
| 1387 | |
---|
| 1388 | typedef BfsVisit Create; |
---|
| 1389 | |
---|
| 1390 | /// \name Named template parameters |
---|
| 1391 | |
---|
| 1392 | ///@{ |
---|
| 1393 | template <class T> |
---|
[257] | 1394 | struct SetReachedMapTraits : public Traits { |
---|
[100] | 1395 | typedef T ReachedMap; |
---|
| 1396 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
[209] | 1397 | throw UninitializedParameter(); |
---|
[100] | 1398 | } |
---|
| 1399 | }; |
---|
[209] | 1400 | /// \brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 1401 | /// ReachedMap type. |
---|
[100] | 1402 | /// |
---|
[244] | 1403 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
---|
[100] | 1404 | template <class T> |
---|
[257] | 1405 | struct SetReachedMap : public BfsVisit< Digraph, Visitor, |
---|
| 1406 | SetReachedMapTraits<T> > { |
---|
| 1407 | typedef BfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
---|
[100] | 1408 | }; |
---|
| 1409 | ///@} |
---|
| 1410 | |
---|
[209] | 1411 | public: |
---|
| 1412 | |
---|
[100] | 1413 | /// \brief Constructor. |
---|
| 1414 | /// |
---|
| 1415 | /// Constructor. |
---|
| 1416 | /// |
---|
[244] | 1417 | /// \param digraph The digraph the algorithm runs on. |
---|
| 1418 | /// \param visitor The visitor object of the algorithm. |
---|
[209] | 1419 | BfsVisit(const Digraph& digraph, Visitor& visitor) |
---|
[100] | 1420 | : _digraph(&digraph), _visitor(&visitor), |
---|
[209] | 1421 | _reached(0), local_reached(false) {} |
---|
| 1422 | |
---|
[100] | 1423 | /// \brief Destructor. |
---|
| 1424 | ~BfsVisit() { |
---|
| 1425 | if(local_reached) delete _reached; |
---|
| 1426 | } |
---|
| 1427 | |
---|
[244] | 1428 | /// \brief Sets the map that indicates which nodes are reached. |
---|
[100] | 1429 | /// |
---|
[244] | 1430 | /// Sets the map that indicates which nodes are reached. |
---|
[100] | 1431 | /// If you don't use this function before calling \ref run(), |
---|
[244] | 1432 | /// it will allocate one. The destructor deallocates this |
---|
[100] | 1433 | /// automatically allocated map, of course. |
---|
| 1434 | /// \return <tt> (*this) </tt> |
---|
| 1435 | BfsVisit &reachedMap(ReachedMap &m) { |
---|
| 1436 | if(local_reached) { |
---|
[209] | 1437 | delete _reached; |
---|
| 1438 | local_reached = false; |
---|
[100] | 1439 | } |
---|
| 1440 | _reached = &m; |
---|
| 1441 | return *this; |
---|
| 1442 | } |
---|
| 1443 | |
---|
| 1444 | public: |
---|
[244] | 1445 | |
---|
[100] | 1446 | /// \name Execution control |
---|
| 1447 | /// The simplest way to execute the algorithm is to use |
---|
[244] | 1448 | /// one of the member functions called \ref lemon::BfsVisit::run() |
---|
| 1449 | /// "run()". |
---|
[100] | 1450 | /// \n |
---|
[244] | 1451 | /// If you need more control on the execution, first you must call |
---|
| 1452 | /// \ref lemon::BfsVisit::init() "init()", then you can add several |
---|
| 1453 | /// source nodes with \ref lemon::BfsVisit::addSource() "addSource()". |
---|
| 1454 | /// Finally \ref lemon::BfsVisit::start() "start()" will perform the |
---|
| 1455 | /// actual path computation. |
---|
[100] | 1456 | |
---|
| 1457 | /// @{ |
---|
[244] | 1458 | |
---|
[100] | 1459 | /// \brief Initializes the internal data structures. |
---|
| 1460 | /// |
---|
| 1461 | /// Initializes the internal data structures. |
---|
| 1462 | void init() { |
---|
| 1463 | create_maps(); |
---|
| 1464 | _list.resize(countNodes(*_digraph)); |
---|
| 1465 | _list_front = _list_back = -1; |
---|
| 1466 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
---|
[209] | 1467 | _reached->set(u, false); |
---|
[100] | 1468 | } |
---|
| 1469 | } |
---|
[209] | 1470 | |
---|
[100] | 1471 | /// \brief Adds a new source node. |
---|
| 1472 | /// |
---|
| 1473 | /// Adds a new source node to the set of nodes to be processed. |
---|
| 1474 | void addSource(Node s) { |
---|
| 1475 | if(!(*_reached)[s]) { |
---|
[209] | 1476 | _reached->set(s,true); |
---|
| 1477 | _visitor->start(s); |
---|
| 1478 | _visitor->reach(s); |
---|
[100] | 1479 | _list[++_list_back] = s; |
---|
[209] | 1480 | } |
---|
[100] | 1481 | } |
---|
[209] | 1482 | |
---|
[100] | 1483 | /// \brief Processes the next node. |
---|
| 1484 | /// |
---|
| 1485 | /// Processes the next node. |
---|
| 1486 | /// |
---|
| 1487 | /// \return The processed node. |
---|
| 1488 | /// |
---|
[244] | 1489 | /// \pre The queue must not be empty. |
---|
[209] | 1490 | Node processNextNode() { |
---|
[100] | 1491 | Node n = _list[++_list_front]; |
---|
| 1492 | _visitor->process(n); |
---|
| 1493 | Arc e; |
---|
| 1494 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1495 | Node m = _digraph->target(e); |
---|
| 1496 | if (!(*_reached)[m]) { |
---|
| 1497 | _visitor->discover(e); |
---|
| 1498 | _visitor->reach(m); |
---|
| 1499 | _reached->set(m, true); |
---|
| 1500 | _list[++_list_back] = m; |
---|
| 1501 | } else { |
---|
| 1502 | _visitor->examine(e); |
---|
| 1503 | } |
---|
| 1504 | } |
---|
| 1505 | return n; |
---|
| 1506 | } |
---|
| 1507 | |
---|
| 1508 | /// \brief Processes the next node. |
---|
| 1509 | /// |
---|
[244] | 1510 | /// Processes the next node and checks if the given target node |
---|
[100] | 1511 | /// is reached. If the target node is reachable from the processed |
---|
[244] | 1512 | /// node, then the \c reach parameter will be set to \c true. |
---|
[100] | 1513 | /// |
---|
| 1514 | /// \param target The target node. |
---|
[244] | 1515 | /// \retval reach Indicates if the target node is reached. |
---|
| 1516 | /// It should be initially \c false. |
---|
| 1517 | /// |
---|
[100] | 1518 | /// \return The processed node. |
---|
| 1519 | /// |
---|
[244] | 1520 | /// \pre The queue must not be empty. |
---|
[100] | 1521 | Node processNextNode(Node target, bool& reach) { |
---|
| 1522 | Node n = _list[++_list_front]; |
---|
| 1523 | _visitor->process(n); |
---|
| 1524 | Arc e; |
---|
| 1525 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1526 | Node m = _digraph->target(e); |
---|
| 1527 | if (!(*_reached)[m]) { |
---|
| 1528 | _visitor->discover(e); |
---|
| 1529 | _visitor->reach(m); |
---|
| 1530 | _reached->set(m, true); |
---|
| 1531 | _list[++_list_back] = m; |
---|
| 1532 | reach = reach || (target == m); |
---|
| 1533 | } else { |
---|
| 1534 | _visitor->examine(e); |
---|
| 1535 | } |
---|
| 1536 | } |
---|
| 1537 | return n; |
---|
| 1538 | } |
---|
| 1539 | |
---|
| 1540 | /// \brief Processes the next node. |
---|
| 1541 | /// |
---|
[244] | 1542 | /// Processes the next node and checks if at least one of reached |
---|
| 1543 | /// nodes has \c true value in the \c nm node map. If one node |
---|
| 1544 | /// with \c true value is reachable from the processed node, then the |
---|
| 1545 | /// \c rnode parameter will be set to the first of such nodes. |
---|
[100] | 1546 | /// |
---|
[244] | 1547 | /// \param nm A \c bool (or convertible) node map that indicates the |
---|
| 1548 | /// possible targets. |
---|
[100] | 1549 | /// \retval rnode The reached target node. |
---|
[244] | 1550 | /// It should be initially \c INVALID. |
---|
| 1551 | /// |
---|
[100] | 1552 | /// \return The processed node. |
---|
| 1553 | /// |
---|
[244] | 1554 | /// \pre The queue must not be empty. |
---|
[100] | 1555 | template <typename NM> |
---|
| 1556 | Node processNextNode(const NM& nm, Node& rnode) { |
---|
| 1557 | Node n = _list[++_list_front]; |
---|
| 1558 | _visitor->process(n); |
---|
| 1559 | Arc e; |
---|
| 1560 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1561 | Node m = _digraph->target(e); |
---|
| 1562 | if (!(*_reached)[m]) { |
---|
| 1563 | _visitor->discover(e); |
---|
| 1564 | _visitor->reach(m); |
---|
| 1565 | _reached->set(m, true); |
---|
| 1566 | _list[++_list_back] = m; |
---|
| 1567 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 1568 | } else { |
---|
| 1569 | _visitor->examine(e); |
---|
| 1570 | } |
---|
| 1571 | } |
---|
| 1572 | return n; |
---|
| 1573 | } |
---|
| 1574 | |
---|
[244] | 1575 | /// \brief The next node to be processed. |
---|
[100] | 1576 | /// |
---|
[244] | 1577 | /// Returns the next node to be processed or \c INVALID if the queue |
---|
| 1578 | /// is empty. |
---|
| 1579 | Node nextNode() const { |
---|
[100] | 1580 | return _list_front != _list_back ? _list[_list_front + 1] : INVALID; |
---|
| 1581 | } |
---|
| 1582 | |
---|
| 1583 | /// \brief Returns \c false if there are nodes |
---|
[244] | 1584 | /// to be processed. |
---|
[100] | 1585 | /// |
---|
| 1586 | /// Returns \c false if there are nodes |
---|
[244] | 1587 | /// to be processed in the queue. |
---|
| 1588 | bool emptyQueue() const { return _list_front == _list_back; } |
---|
[100] | 1589 | |
---|
| 1590 | /// \brief Returns the number of the nodes to be processed. |
---|
| 1591 | /// |
---|
| 1592 | /// Returns the number of the nodes to be processed in the queue. |
---|
[244] | 1593 | int queueSize() const { return _list_back - _list_front; } |
---|
[209] | 1594 | |
---|
[100] | 1595 | /// \brief Executes the algorithm. |
---|
| 1596 | /// |
---|
| 1597 | /// Executes the algorithm. |
---|
| 1598 | /// |
---|
[244] | 1599 | /// This method runs the %BFS algorithm from the root node(s) |
---|
| 1600 | /// in order to compute the shortest path to each node. |
---|
| 1601 | /// |
---|
| 1602 | /// The algorithm computes |
---|
| 1603 | /// - the shortest path tree (forest), |
---|
| 1604 | /// - the distance of each node from the root(s). |
---|
| 1605 | /// |
---|
| 1606 | /// \pre init() must be called and at least one root node should be added |
---|
[100] | 1607 | /// with addSource() before using this function. |
---|
[244] | 1608 | /// |
---|
| 1609 | /// \note <tt>b.start()</tt> is just a shortcut of the following code. |
---|
| 1610 | /// \code |
---|
| 1611 | /// while ( !b.emptyQueue() ) { |
---|
| 1612 | /// b.processNextNode(); |
---|
| 1613 | /// } |
---|
| 1614 | /// \endcode |
---|
[100] | 1615 | void start() { |
---|
| 1616 | while ( !emptyQueue() ) processNextNode(); |
---|
| 1617 | } |
---|
[209] | 1618 | |
---|
[244] | 1619 | /// \brief Executes the algorithm until the given target node is reached. |
---|
[100] | 1620 | /// |
---|
[244] | 1621 | /// Executes the algorithm until the given target node is reached. |
---|
[100] | 1622 | /// |
---|
[244] | 1623 | /// This method runs the %BFS algorithm from the root node(s) |
---|
[286] | 1624 | /// in order to compute the shortest path to \c t. |
---|
[244] | 1625 | /// |
---|
| 1626 | /// The algorithm computes |
---|
[286] | 1627 | /// - the shortest path to \c t, |
---|
| 1628 | /// - the distance of \c t from the root(s). |
---|
[244] | 1629 | /// |
---|
| 1630 | /// \pre init() must be called and at least one root node should be |
---|
| 1631 | /// added with addSource() before using this function. |
---|
| 1632 | /// |
---|
| 1633 | /// \note <tt>b.start(t)</tt> is just a shortcut of the following code. |
---|
| 1634 | /// \code |
---|
| 1635 | /// bool reach = false; |
---|
| 1636 | /// while ( !b.emptyQueue() && !reach ) { |
---|
| 1637 | /// b.processNextNode(t, reach); |
---|
| 1638 | /// } |
---|
| 1639 | /// \endcode |
---|
[286] | 1640 | void start(Node t) { |
---|
[100] | 1641 | bool reach = false; |
---|
[286] | 1642 | while ( !emptyQueue() && !reach ) processNextNode(t, reach); |
---|
[100] | 1643 | } |
---|
[209] | 1644 | |
---|
[100] | 1645 | /// \brief Executes the algorithm until a condition is met. |
---|
| 1646 | /// |
---|
| 1647 | /// Executes the algorithm until a condition is met. |
---|
| 1648 | /// |
---|
[244] | 1649 | /// This method runs the %BFS algorithm from the root node(s) in |
---|
| 1650 | /// order to compute the shortest path to a node \c v with |
---|
| 1651 | /// <tt>nm[v]</tt> true, if such a node can be found. |
---|
[100] | 1652 | /// |
---|
[244] | 1653 | /// \param nm must be a bool (or convertible) node map. The |
---|
| 1654 | /// algorithm will stop when it reaches a node \c v with |
---|
[100] | 1655 | /// <tt>nm[v]</tt> true. |
---|
| 1656 | /// |
---|
[244] | 1657 | /// \return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 1658 | /// \c INVALID if no such node was found. |
---|
| 1659 | /// |
---|
| 1660 | /// \pre init() must be called and at least one root node should be |
---|
| 1661 | /// added with addSource() before using this function. |
---|
| 1662 | /// |
---|
| 1663 | /// \note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
---|
| 1664 | /// \code |
---|
| 1665 | /// Node rnode = INVALID; |
---|
| 1666 | /// while ( !b.emptyQueue() && rnode == INVALID ) { |
---|
| 1667 | /// b.processNextNode(nm, rnode); |
---|
| 1668 | /// } |
---|
| 1669 | /// return rnode; |
---|
| 1670 | /// \endcode |
---|
[100] | 1671 | template <typename NM> |
---|
| 1672 | Node start(const NM &nm) { |
---|
| 1673 | Node rnode = INVALID; |
---|
| 1674 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 1675 | processNextNode(nm, rnode); |
---|
[100] | 1676 | } |
---|
| 1677 | return rnode; |
---|
| 1678 | } |
---|
| 1679 | |
---|
[286] | 1680 | /// \brief Runs the algorithm from the given source node. |
---|
[100] | 1681 | /// |
---|
[244] | 1682 | /// This method runs the %BFS algorithm from node \c s |
---|
| 1683 | /// in order to compute the shortest path to each node. |
---|
| 1684 | /// |
---|
| 1685 | /// The algorithm computes |
---|
| 1686 | /// - the shortest path tree, |
---|
| 1687 | /// - the distance of each node from the root. |
---|
| 1688 | /// |
---|
| 1689 | /// \note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1690 | ///\code |
---|
| 1691 | /// b.init(); |
---|
| 1692 | /// b.addSource(s); |
---|
| 1693 | /// b.start(); |
---|
| 1694 | ///\endcode |
---|
| 1695 | void run(Node s) { |
---|
| 1696 | init(); |
---|
| 1697 | addSource(s); |
---|
| 1698 | start(); |
---|
| 1699 | } |
---|
| 1700 | |
---|
[286] | 1701 | /// \brief Finds the shortest path between \c s and \c t. |
---|
| 1702 | /// |
---|
| 1703 | /// This method runs the %BFS algorithm from node \c s |
---|
| 1704 | /// in order to compute the shortest path to node \c t |
---|
| 1705 | /// (it stops searching when \c t is processed). |
---|
| 1706 | /// |
---|
| 1707 | /// \return \c true if \c t is reachable form \c s. |
---|
| 1708 | /// |
---|
| 1709 | /// \note Apart from the return value, <tt>b.run(s,t)</tt> is just a |
---|
| 1710 | /// shortcut of the following code. |
---|
| 1711 | ///\code |
---|
| 1712 | /// b.init(); |
---|
| 1713 | /// b.addSource(s); |
---|
| 1714 | /// b.start(t); |
---|
| 1715 | ///\endcode |
---|
| 1716 | bool run(Node s,Node t) { |
---|
| 1717 | init(); |
---|
| 1718 | addSource(s); |
---|
| 1719 | start(t); |
---|
| 1720 | return reached(t); |
---|
| 1721 | } |
---|
| 1722 | |
---|
[244] | 1723 | /// \brief Runs the algorithm to visit all nodes in the digraph. |
---|
[209] | 1724 | /// |
---|
[100] | 1725 | /// This method runs the %BFS algorithm in order to |
---|
[244] | 1726 | /// compute the shortest path to each node. |
---|
[100] | 1727 | /// |
---|
[244] | 1728 | /// The algorithm computes |
---|
| 1729 | /// - the shortest path tree (forest), |
---|
| 1730 | /// - the distance of each node from the root(s). |
---|
| 1731 | /// |
---|
| 1732 | /// \note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1733 | ///\code |
---|
| 1734 | /// b.init(); |
---|
[244] | 1735 | /// for (NodeIt n(gr); n != INVALID; ++n) { |
---|
| 1736 | /// if (!b.reached(n)) { |
---|
| 1737 | /// b.addSource(n); |
---|
[100] | 1738 | /// b.start(); |
---|
| 1739 | /// } |
---|
| 1740 | /// } |
---|
| 1741 | ///\endcode |
---|
| 1742 | void run() { |
---|
| 1743 | init(); |
---|
| 1744 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
| 1745 | if (!reached(it)) { |
---|
| 1746 | addSource(it); |
---|
| 1747 | start(); |
---|
| 1748 | } |
---|
| 1749 | } |
---|
| 1750 | } |
---|
[244] | 1751 | |
---|
[100] | 1752 | ///@} |
---|
| 1753 | |
---|
| 1754 | /// \name Query Functions |
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| 1755 | /// The result of the %BFS algorithm can be obtained using these |
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| 1756 | /// functions.\n |
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[244] | 1757 | /// Either \ref lemon::BfsVisit::run() "run()" or |
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| 1758 | /// \ref lemon::BfsVisit::start() "start()" must be called before |
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| 1759 | /// using them. |
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[100] | 1760 | ///@{ |
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| 1761 | |
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[244] | 1762 | /// \brief Checks if a node is reachable from the root(s). |
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[100] | 1763 | /// |
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| 1764 | /// Returns \c true if \c v is reachable from the root(s). |
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| 1765 | /// \pre Either \ref run() or \ref start() |
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| 1766 | /// must be called before using this function. |
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| 1767 | bool reached(Node v) { return (*_reached)[v]; } |
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[244] | 1768 | |
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[100] | 1769 | ///@} |
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[244] | 1770 | |
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[100] | 1771 | }; |
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| 1772 | |
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| 1773 | } //END OF NAMESPACE LEMON |
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| 1774 | |
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| 1775 | #endif |
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