[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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| 57 | static PredMap *createPredMap(const Digraph &g) |
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[100] | 58 | { |
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[244] | 59 | return new PredMap(g); |
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[100] | 60 | } |
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[244] | 61 | |
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[100] | 62 | ///The type of the map that indicates which nodes are processed. |
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[209] | 63 | |
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[100] | 64 | ///The type of the map that indicates which nodes are processed. |
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| 65 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 66 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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[244] | 67 | ///Instantiates a \ref ProcessedMap. |
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[209] | 68 | |
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| 69 | ///This function instantiates a \ref ProcessedMap. |
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[100] | 70 | ///\param g is the digraph, to which |
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| 71 | ///we would like to define the \ref ProcessedMap |
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| 72 | #ifdef DOXYGEN |
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[244] | 73 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 74 | #else |
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[244] | 75 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 76 | #endif |
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| 77 | { |
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| 78 | return new ProcessedMap(); |
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| 79 | } |
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[244] | 80 | |
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[100] | 81 | ///The type of the map that indicates which nodes are reached. |
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[209] | 82 | |
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[100] | 83 | ///The type of the map that indicates which nodes are reached. |
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[244] | 84 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 85 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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[244] | 86 | ///Instantiates a \ref ReachedMap. |
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[209] | 87 | |
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| 88 | ///This function instantiates a \ref ReachedMap. |
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[244] | 89 | ///\param g is the digraph, to which |
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[100] | 90 | ///we would like to define the \ref ReachedMap. |
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[244] | 91 | static ReachedMap *createReachedMap(const Digraph &g) |
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[100] | 92 | { |
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[244] | 93 | return new ReachedMap(g); |
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[100] | 94 | } |
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[209] | 95 | |
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[244] | 96 | ///The type of the map that stores the distances of the nodes. |
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| 97 | |
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| 98 | ///The type of the map that stores the distances of the nodes. |
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[100] | 99 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 100 | typedef typename Digraph::template NodeMap<int> DistMap; |
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[244] | 101 | ///Instantiates a \ref DistMap. |
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[209] | 102 | |
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| 103 | ///This function instantiates a \ref DistMap. |
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[244] | 104 | ///\param g is the digraph, to which we would like to define the |
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| 105 | ///\ref DistMap. |
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| 106 | static DistMap *createDistMap(const Digraph &g) |
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[100] | 107 | { |
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[244] | 108 | return new DistMap(g); |
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[100] | 109 | } |
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| 110 | }; |
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[209] | 111 | |
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[100] | 112 | ///%BFS algorithm class. |
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[209] | 113 | |
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[100] | 114 | ///\ingroup search |
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| 115 | ///This class provides an efficient implementation of the %BFS algorithm. |
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| 116 | /// |
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[278] | 117 | ///There is also a \ref bfs() "function-type interface" for the BFS |
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[244] | 118 | ///algorithm, which is convenient in the simplier cases and it can be |
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| 119 | ///used easier. |
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| 120 | /// |
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| 121 | ///\tparam GR The type of the digraph the algorithm runs on. |
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| 122 | ///The default value is \ref ListDigraph. The value of GR is not used |
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| 123 | ///directly by \ref Bfs, it is only passed to \ref BfsDefaultTraits. |
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[157] | 124 | ///\tparam TR Traits class to set various data types used by the algorithm. |
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[100] | 125 | ///The default traits class is |
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| 126 | ///\ref BfsDefaultTraits "BfsDefaultTraits<GR>". |
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| 127 | ///See \ref BfsDefaultTraits for the documentation of |
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| 128 | ///a Bfs traits class. |
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| 129 | #ifdef DOXYGEN |
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| 130 | template <typename GR, |
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[209] | 131 | typename TR> |
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[100] | 132 | #else |
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| 133 | template <typename GR=ListDigraph, |
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[209] | 134 | typename TR=BfsDefaultTraits<GR> > |
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[100] | 135 | #endif |
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| 136 | class Bfs { |
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| 137 | public: |
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[244] | 138 | ///\ref Exception for uninitialized parameters. |
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| 139 | |
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| 140 | ///This error represents problems in the initialization of the |
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| 141 | ///parameters of the algorithm. |
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[100] | 142 | class UninitializedParameter : public lemon::UninitializedParameter { |
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| 143 | public: |
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| 144 | virtual const char* what() const throw() { |
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[209] | 145 | return "lemon::Bfs::UninitializedParameter"; |
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[100] | 146 | } |
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| 147 | }; |
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| 148 | |
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[244] | 149 | ///The type of the digraph the algorithm runs on. |
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[100] | 150 | typedef typename TR::Digraph Digraph; |
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[209] | 151 | |
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[244] | 152 | ///\brief The type of the map that stores the predecessor arcs of the |
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| 153 | ///shortest paths. |
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[100] | 154 | typedef typename TR::PredMap PredMap; |
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[244] | 155 | ///The type of the map that stores the distances of the nodes. |
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| 156 | typedef typename TR::DistMap DistMap; |
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| 157 | ///The type of the map that indicates which nodes are reached. |
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[100] | 158 | typedef typename TR::ReachedMap ReachedMap; |
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[244] | 159 | ///The type of the map that indicates which nodes are processed. |
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[100] | 160 | typedef typename TR::ProcessedMap ProcessedMap; |
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[244] | 161 | ///The type of the paths. |
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| 162 | typedef PredMapPath<Digraph, PredMap> Path; |
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| 163 | |
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| 164 | ///The traits class. |
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| 165 | typedef TR Traits; |
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| 166 | |
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[100] | 167 | private: |
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| 168 | |
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| 169 | typedef typename Digraph::Node Node; |
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| 170 | typedef typename Digraph::NodeIt NodeIt; |
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| 171 | typedef typename Digraph::Arc Arc; |
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| 172 | typedef typename Digraph::OutArcIt OutArcIt; |
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| 173 | |
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[244] | 174 | //Pointer to the underlying digraph. |
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[100] | 175 | const Digraph *G; |
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[244] | 176 | //Pointer to the map of predecessor arcs. |
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[100] | 177 | PredMap *_pred; |
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[244] | 178 | //Indicates if _pred is locally allocated (true) or not. |
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[100] | 179 | bool local_pred; |
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[244] | 180 | //Pointer to the map of distances. |
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[100] | 181 | DistMap *_dist; |
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[244] | 182 | //Indicates if _dist is locally allocated (true) or not. |
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[100] | 183 | bool local_dist; |
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[244] | 184 | //Pointer to the map of reached status of the nodes. |
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[100] | 185 | ReachedMap *_reached; |
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[244] | 186 | //Indicates if _reached is locally allocated (true) or not. |
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[100] | 187 | bool local_reached; |
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[244] | 188 | //Pointer to the map of processed status of the nodes. |
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[100] | 189 | ProcessedMap *_processed; |
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[244] | 190 | //Indicates if _processed is locally allocated (true) or not. |
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[100] | 191 | bool local_processed; |
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| 192 | |
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| 193 | std::vector<typename Digraph::Node> _queue; |
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| 194 | int _queue_head,_queue_tail,_queue_next_dist; |
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| 195 | int _curr_dist; |
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| 196 | |
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[280] | 197 | //Creates the maps if necessary. |
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[209] | 198 | void create_maps() |
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[100] | 199 | { |
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| 200 | if(!_pred) { |
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[209] | 201 | local_pred = true; |
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| 202 | _pred = Traits::createPredMap(*G); |
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[100] | 203 | } |
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| 204 | if(!_dist) { |
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[209] | 205 | local_dist = true; |
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| 206 | _dist = Traits::createDistMap(*G); |
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[100] | 207 | } |
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| 208 | if(!_reached) { |
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[209] | 209 | local_reached = true; |
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| 210 | _reached = Traits::createReachedMap(*G); |
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[100] | 211 | } |
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| 212 | if(!_processed) { |
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[209] | 213 | local_processed = true; |
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| 214 | _processed = Traits::createProcessedMap(*G); |
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[100] | 215 | } |
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| 216 | } |
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| 217 | |
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| 218 | protected: |
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[209] | 219 | |
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[100] | 220 | Bfs() {} |
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[209] | 221 | |
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[100] | 222 | public: |
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[209] | 223 | |
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[100] | 224 | typedef Bfs Create; |
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| 225 | |
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| 226 | ///\name Named template parameters |
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| 227 | |
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| 228 | ///@{ |
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| 229 | |
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| 230 | template <class T> |
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[257] | 231 | struct SetPredMapTraits : public Traits { |
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[100] | 232 | typedef T PredMap; |
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[209] | 233 | static PredMap *createPredMap(const Digraph &) |
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[100] | 234 | { |
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[209] | 235 | throw UninitializedParameter(); |
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[100] | 236 | } |
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| 237 | }; |
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| 238 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 239 | ///\ref PredMap type. |
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[100] | 240 | /// |
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[244] | 241 | ///\ref named-templ-param "Named parameter" for setting |
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| 242 | ///\ref PredMap type. |
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[100] | 243 | template <class T> |
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[257] | 244 | struct SetPredMap : public Bfs< Digraph, SetPredMapTraits<T> > { |
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| 245 | typedef Bfs< Digraph, SetPredMapTraits<T> > Create; |
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[100] | 246 | }; |
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[209] | 247 | |
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[100] | 248 | template <class T> |
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[257] | 249 | struct SetDistMapTraits : public Traits { |
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[100] | 250 | typedef T DistMap; |
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[209] | 251 | static DistMap *createDistMap(const Digraph &) |
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[100] | 252 | { |
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[209] | 253 | throw UninitializedParameter(); |
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[100] | 254 | } |
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| 255 | }; |
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| 256 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 257 | ///\ref DistMap type. |
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[100] | 258 | /// |
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[244] | 259 | ///\ref named-templ-param "Named parameter" for setting |
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| 260 | ///\ref DistMap type. |
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[100] | 261 | template <class T> |
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[257] | 262 | struct SetDistMap : public Bfs< Digraph, SetDistMapTraits<T> > { |
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| 263 | typedef Bfs< Digraph, SetDistMapTraits<T> > Create; |
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[100] | 264 | }; |
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[209] | 265 | |
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[100] | 266 | template <class T> |
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[257] | 267 | struct SetReachedMapTraits : public Traits { |
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[100] | 268 | typedef T ReachedMap; |
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[209] | 269 | static ReachedMap *createReachedMap(const Digraph &) |
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[100] | 270 | { |
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[209] | 271 | throw UninitializedParameter(); |
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[100] | 272 | } |
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| 273 | }; |
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| 274 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 275 | ///\ref ReachedMap type. |
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[100] | 276 | /// |
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[244] | 277 | ///\ref named-templ-param "Named parameter" for setting |
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| 278 | ///\ref ReachedMap type. |
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[100] | 279 | template <class T> |
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[257] | 280 | struct SetReachedMap : public Bfs< Digraph, SetReachedMapTraits<T> > { |
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| 281 | typedef Bfs< Digraph, SetReachedMapTraits<T> > Create; |
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[100] | 282 | }; |
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[209] | 283 | |
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[100] | 284 | template <class T> |
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[257] | 285 | struct SetProcessedMapTraits : public Traits { |
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[100] | 286 | typedef T ProcessedMap; |
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[209] | 287 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 288 | { |
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[209] | 289 | throw UninitializedParameter(); |
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[100] | 290 | } |
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| 291 | }; |
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| 292 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 293 | ///\ref ProcessedMap type. |
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[100] | 294 | /// |
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[244] | 295 | ///\ref named-templ-param "Named parameter" for setting |
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| 296 | ///\ref ProcessedMap type. |
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[100] | 297 | template <class T> |
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[257] | 298 | struct SetProcessedMap : public Bfs< Digraph, SetProcessedMapTraits<T> > { |
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| 299 | typedef Bfs< Digraph, SetProcessedMapTraits<T> > Create; |
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[100] | 300 | }; |
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[209] | 301 | |
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[257] | 302 | struct SetStandardProcessedMapTraits : public Traits { |
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[100] | 303 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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[244] | 304 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 305 | { |
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[244] | 306 | return new ProcessedMap(g); |
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[100] | 307 | } |
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| 308 | }; |
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[244] | 309 | ///\brief \ref named-templ-param "Named parameter" for setting |
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| 310 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 311 | /// |
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[244] | 312 | ///\ref named-templ-param "Named parameter" for setting |
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| 313 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 314 | ///If you don't set it explicitly, it will be automatically allocated. |
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[257] | 315 | struct SetStandardProcessedMap : |
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| 316 | public Bfs< Digraph, SetStandardProcessedMapTraits > { |
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| 317 | typedef Bfs< Digraph, SetStandardProcessedMapTraits > Create; |
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[100] | 318 | }; |
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[209] | 319 | |
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[100] | 320 | ///@} |
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| 321 | |
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[209] | 322 | public: |
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| 323 | |
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[100] | 324 | ///Constructor. |
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[209] | 325 | |
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[244] | 326 | ///Constructor. |
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| 327 | ///\param g The digraph the algorithm runs on. |
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| 328 | Bfs(const Digraph &g) : |
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| 329 | G(&g), |
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[100] | 330 | _pred(NULL), local_pred(false), |
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| 331 | _dist(NULL), local_dist(false), |
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| 332 | _reached(NULL), local_reached(false), |
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| 333 | _processed(NULL), local_processed(false) |
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| 334 | { } |
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[209] | 335 | |
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[100] | 336 | ///Destructor. |
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[209] | 337 | ~Bfs() |
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[100] | 338 | { |
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| 339 | if(local_pred) delete _pred; |
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| 340 | if(local_dist) delete _dist; |
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| 341 | if(local_reached) delete _reached; |
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| 342 | if(local_processed) delete _processed; |
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| 343 | } |
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| 344 | |
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[244] | 345 | ///Sets the map that stores the predecessor arcs. |
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[100] | 346 | |
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[244] | 347 | ///Sets the map that stores the predecessor arcs. |
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[100] | 348 | ///If you don't use this function before calling \ref run(), |
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| 349 | ///it will allocate one. The destructor deallocates this |
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| 350 | ///automatically allocated map, of course. |
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| 351 | ///\return <tt> (*this) </tt> |
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[209] | 352 | Bfs &predMap(PredMap &m) |
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[100] | 353 | { |
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| 354 | if(local_pred) { |
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[209] | 355 | delete _pred; |
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| 356 | local_pred=false; |
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[100] | 357 | } |
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| 358 | _pred = &m; |
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| 359 | return *this; |
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| 360 | } |
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| 361 | |
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[244] | 362 | ///Sets the map that indicates which nodes are reached. |
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[100] | 363 | |
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[244] | 364 | ///Sets the map that indicates which nodes are reached. |
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[100] | 365 | ///If you don't use this function before calling \ref run(), |
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| 366 | ///it will allocate one. The destructor deallocates this |
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| 367 | ///automatically allocated map, of course. |
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| 368 | ///\return <tt> (*this) </tt> |
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[209] | 369 | Bfs &reachedMap(ReachedMap &m) |
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[100] | 370 | { |
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| 371 | if(local_reached) { |
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[209] | 372 | delete _reached; |
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| 373 | local_reached=false; |
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[100] | 374 | } |
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| 375 | _reached = &m; |
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| 376 | return *this; |
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| 377 | } |
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| 378 | |
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[244] | 379 | ///Sets the map that indicates which nodes are processed. |
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[100] | 380 | |
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[244] | 381 | ///Sets the map that indicates which nodes are processed. |
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[100] | 382 | ///If you don't use this function before calling \ref run(), |
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| 383 | ///it will allocate one. The destructor deallocates this |
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| 384 | ///automatically allocated map, of course. |
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| 385 | ///\return <tt> (*this) </tt> |
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[209] | 386 | Bfs &processedMap(ProcessedMap &m) |
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[100] | 387 | { |
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| 388 | if(local_processed) { |
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[209] | 389 | delete _processed; |
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| 390 | local_processed=false; |
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[100] | 391 | } |
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| 392 | _processed = &m; |
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| 393 | return *this; |
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| 394 | } |
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| 395 | |
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[244] | 396 | ///Sets the map that stores the distances of the nodes. |
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[100] | 397 | |
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[244] | 398 | ///Sets the map that stores the distances of the nodes calculated by |
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| 399 | ///the algorithm. |
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[100] | 400 | ///If you don't use this function before calling \ref run(), |
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| 401 | ///it will allocate one. The destructor deallocates this |
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| 402 | ///automatically allocated map, of course. |
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| 403 | ///\return <tt> (*this) </tt> |
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[209] | 404 | Bfs &distMap(DistMap &m) |
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[100] | 405 | { |
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| 406 | if(local_dist) { |
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[209] | 407 | delete _dist; |
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| 408 | local_dist=false; |
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[100] | 409 | } |
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| 410 | _dist = &m; |
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| 411 | return *this; |
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| 412 | } |
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| 413 | |
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| 414 | public: |
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[244] | 415 | |
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[100] | 416 | ///\name Execution control |
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| 417 | ///The simplest way to execute the algorithm is to use |
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[244] | 418 | ///one of the member functions called \ref lemon::Bfs::run() "run()". |
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[100] | 419 | ///\n |
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[244] | 420 | ///If you need more control on the execution, first you must call |
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| 421 | ///\ref lemon::Bfs::init() "init()", then you can add several source |
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| 422 | ///nodes with \ref lemon::Bfs::addSource() "addSource()". |
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| 423 | ///Finally \ref lemon::Bfs::start() "start()" will perform the |
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| 424 | ///actual path computation. |
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[100] | 425 | |
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| 426 | ///@{ |
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| 427 | |
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[244] | 428 | ///Initializes the internal data structures. |
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| 429 | |
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[100] | 430 | ///Initializes the internal data structures. |
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| 431 | /// |
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| 432 | void init() |
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| 433 | { |
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| 434 | create_maps(); |
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| 435 | _queue.resize(countNodes(*G)); |
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| 436 | _queue_head=_queue_tail=0; |
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| 437 | _curr_dist=1; |
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| 438 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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[209] | 439 | _pred->set(u,INVALID); |
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| 440 | _reached->set(u,false); |
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| 441 | _processed->set(u,false); |
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[100] | 442 | } |
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| 443 | } |
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[209] | 444 | |
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[100] | 445 | ///Adds a new source node. |
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| 446 | |
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| 447 | ///Adds a new source node to the set of nodes to be processed. |
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| 448 | /// |
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| 449 | void addSource(Node s) |
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| 450 | { |
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| 451 | if(!(*_reached)[s]) |
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[209] | 452 | { |
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| 453 | _reached->set(s,true); |
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| 454 | _pred->set(s,INVALID); |
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| 455 | _dist->set(s,0); |
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| 456 | _queue[_queue_head++]=s; |
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| 457 | _queue_next_dist=_queue_head; |
---|
| 458 | } |
---|
[100] | 459 | } |
---|
[209] | 460 | |
---|
[100] | 461 | ///Processes the next node. |
---|
| 462 | |
---|
| 463 | ///Processes the next node. |
---|
| 464 | /// |
---|
| 465 | ///\return The processed node. |
---|
| 466 | /// |
---|
[244] | 467 | ///\pre The queue must not be empty. |
---|
[100] | 468 | Node processNextNode() |
---|
| 469 | { |
---|
| 470 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 471 | _curr_dist++; |
---|
| 472 | _queue_next_dist=_queue_head; |
---|
[100] | 473 | } |
---|
| 474 | Node n=_queue[_queue_tail++]; |
---|
| 475 | _processed->set(n,true); |
---|
| 476 | Node m; |
---|
| 477 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 478 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 479 | _queue[_queue_head++]=m; |
---|
| 480 | _reached->set(m,true); |
---|
| 481 | _pred->set(m,e); |
---|
| 482 | _dist->set(m,_curr_dist); |
---|
| 483 | } |
---|
[100] | 484 | return n; |
---|
| 485 | } |
---|
| 486 | |
---|
| 487 | ///Processes the next node. |
---|
| 488 | |
---|
[244] | 489 | ///Processes the next node and checks if the given target node |
---|
[100] | 490 | ///is reached. If the target node is reachable from the processed |
---|
[244] | 491 | ///node, then the \c reach parameter will be set to \c true. |
---|
[100] | 492 | /// |
---|
| 493 | ///\param target The target node. |
---|
[244] | 494 | ///\retval reach Indicates if the target node is reached. |
---|
| 495 | ///It should be initially \c false. |
---|
| 496 | /// |
---|
[100] | 497 | ///\return The processed node. |
---|
| 498 | /// |
---|
[244] | 499 | ///\pre The queue must not be empty. |
---|
[100] | 500 | Node processNextNode(Node target, bool& reach) |
---|
| 501 | { |
---|
| 502 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 503 | _curr_dist++; |
---|
| 504 | _queue_next_dist=_queue_head; |
---|
[100] | 505 | } |
---|
| 506 | Node n=_queue[_queue_tail++]; |
---|
| 507 | _processed->set(n,true); |
---|
| 508 | Node m; |
---|
| 509 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 510 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 511 | _queue[_queue_head++]=m; |
---|
| 512 | _reached->set(m,true); |
---|
| 513 | _pred->set(m,e); |
---|
| 514 | _dist->set(m,_curr_dist); |
---|
[100] | 515 | reach = reach || (target == m); |
---|
[209] | 516 | } |
---|
[100] | 517 | return n; |
---|
| 518 | } |
---|
| 519 | |
---|
| 520 | ///Processes the next node. |
---|
| 521 | |
---|
[244] | 522 | ///Processes the next node and checks if at least one of reached |
---|
| 523 | ///nodes has \c true value in the \c nm node map. If one node |
---|
| 524 | ///with \c true value is reachable from the processed node, then the |
---|
| 525 | ///\c rnode parameter will be set to the first of such nodes. |
---|
[100] | 526 | /// |
---|
[244] | 527 | ///\param nm A \c bool (or convertible) node map that indicates the |
---|
| 528 | ///possible targets. |
---|
[100] | 529 | ///\retval rnode The reached target node. |
---|
[244] | 530 | ///It should be initially \c INVALID. |
---|
| 531 | /// |
---|
[100] | 532 | ///\return The processed node. |
---|
| 533 | /// |
---|
[244] | 534 | ///\pre The queue must not be empty. |
---|
[100] | 535 | template<class NM> |
---|
| 536 | Node processNextNode(const NM& nm, Node& rnode) |
---|
| 537 | { |
---|
| 538 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 539 | _curr_dist++; |
---|
| 540 | _queue_next_dist=_queue_head; |
---|
[100] | 541 | } |
---|
| 542 | Node n=_queue[_queue_tail++]; |
---|
| 543 | _processed->set(n,true); |
---|
| 544 | Node m; |
---|
| 545 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 546 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 547 | _queue[_queue_head++]=m; |
---|
| 548 | _reached->set(m,true); |
---|
| 549 | _pred->set(m,e); |
---|
| 550 | _dist->set(m,_curr_dist); |
---|
| 551 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 552 | } |
---|
[100] | 553 | return n; |
---|
| 554 | } |
---|
[209] | 555 | |
---|
[244] | 556 | ///The next node to be processed. |
---|
[100] | 557 | |
---|
[244] | 558 | ///Returns the next node to be processed or \c INVALID if the queue |
---|
| 559 | ///is empty. |
---|
| 560 | Node nextNode() const |
---|
[209] | 561 | { |
---|
[100] | 562 | return _queue_tail<_queue_head?_queue[_queue_tail]:INVALID; |
---|
| 563 | } |
---|
[209] | 564 | |
---|
[100] | 565 | ///\brief Returns \c false if there are nodes |
---|
[244] | 566 | ///to be processed. |
---|
[100] | 567 | /// |
---|
| 568 | ///Returns \c false if there are nodes |
---|
[244] | 569 | ///to be processed in the queue. |
---|
| 570 | bool emptyQueue() const { return _queue_tail==_queue_head; } |
---|
| 571 | |
---|
[100] | 572 | ///Returns the number of the nodes to be processed. |
---|
[209] | 573 | |
---|
[100] | 574 | ///Returns the number of the nodes to be processed in the queue. |
---|
[244] | 575 | int queueSize() const { return _queue_head-_queue_tail; } |
---|
[209] | 576 | |
---|
[100] | 577 | ///Executes the algorithm. |
---|
| 578 | |
---|
| 579 | ///Executes the algorithm. |
---|
| 580 | /// |
---|
[244] | 581 | ///This method runs the %BFS algorithm from the root node(s) |
---|
| 582 | ///in order to compute the shortest path to each node. |
---|
[100] | 583 | /// |
---|
[244] | 584 | ///The algorithm computes |
---|
| 585 | ///- the shortest path tree (forest), |
---|
| 586 | ///- the distance of each node from the root(s). |
---|
| 587 | /// |
---|
| 588 | ///\pre init() must be called and at least one root node should be |
---|
| 589 | ///added with addSource() before using this function. |
---|
| 590 | /// |
---|
| 591 | ///\note <tt>b.start()</tt> is just a shortcut of the following code. |
---|
| 592 | ///\code |
---|
| 593 | /// while ( !b.emptyQueue() ) { |
---|
| 594 | /// b.processNextNode(); |
---|
| 595 | /// } |
---|
| 596 | ///\endcode |
---|
[100] | 597 | void start() |
---|
| 598 | { |
---|
| 599 | while ( !emptyQueue() ) processNextNode(); |
---|
| 600 | } |
---|
[209] | 601 | |
---|
[244] | 602 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 603 | |
---|
[244] | 604 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 605 | /// |
---|
| 606 | ///This method runs the %BFS algorithm from the root node(s) |
---|
[286] | 607 | ///in order to compute the shortest path to \c t. |
---|
[244] | 608 | /// |
---|
[100] | 609 | ///The algorithm computes |
---|
[286] | 610 | ///- the shortest path to \c t, |
---|
| 611 | ///- the distance of \c t from the root(s). |
---|
[244] | 612 | /// |
---|
| 613 | ///\pre init() must be called and at least one root node should be |
---|
| 614 | ///added with addSource() before using this function. |
---|
| 615 | /// |
---|
| 616 | ///\note <tt>b.start(t)</tt> is just a shortcut of the following code. |
---|
| 617 | ///\code |
---|
| 618 | /// bool reach = false; |
---|
| 619 | /// while ( !b.emptyQueue() && !reach ) { |
---|
| 620 | /// b.processNextNode(t, reach); |
---|
| 621 | /// } |
---|
| 622 | ///\endcode |
---|
[286] | 623 | void start(Node t) |
---|
[100] | 624 | { |
---|
| 625 | bool reach = false; |
---|
[286] | 626 | while ( !emptyQueue() && !reach ) processNextNode(t, reach); |
---|
[100] | 627 | } |
---|
[209] | 628 | |
---|
[100] | 629 | ///Executes the algorithm until a condition is met. |
---|
| 630 | |
---|
| 631 | ///Executes the algorithm until a condition is met. |
---|
| 632 | /// |
---|
[244] | 633 | ///This method runs the %BFS algorithm from the root node(s) in |
---|
| 634 | ///order to compute the shortest path to a node \c v with |
---|
| 635 | /// <tt>nm[v]</tt> true, if such a node can be found. |
---|
[100] | 636 | /// |
---|
[244] | 637 | ///\param nm A \c bool (or convertible) node map. The algorithm |
---|
| 638 | ///will stop when it reaches a node \c v with <tt>nm[v]</tt> true. |
---|
[100] | 639 | /// |
---|
| 640 | ///\return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 641 | ///\c INVALID if no such node was found. |
---|
[244] | 642 | /// |
---|
| 643 | ///\pre init() must be called and at least one root node should be |
---|
| 644 | ///added with addSource() before using this function. |
---|
| 645 | /// |
---|
| 646 | ///\note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
---|
| 647 | ///\code |
---|
| 648 | /// Node rnode = INVALID; |
---|
| 649 | /// while ( !b.emptyQueue() && rnode == INVALID ) { |
---|
| 650 | /// b.processNextNode(nm, rnode); |
---|
| 651 | /// } |
---|
| 652 | /// return rnode; |
---|
| 653 | ///\endcode |
---|
| 654 | template<class NodeBoolMap> |
---|
| 655 | Node start(const NodeBoolMap &nm) |
---|
[100] | 656 | { |
---|
| 657 | Node rnode = INVALID; |
---|
| 658 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 659 | processNextNode(nm, rnode); |
---|
[100] | 660 | } |
---|
| 661 | return rnode; |
---|
| 662 | } |
---|
[209] | 663 | |
---|
[286] | 664 | ///Runs the algorithm from the given source node. |
---|
[209] | 665 | |
---|
[244] | 666 | ///This method runs the %BFS algorithm from node \c s |
---|
| 667 | ///in order to compute the shortest path to each node. |
---|
[100] | 668 | /// |
---|
[244] | 669 | ///The algorithm computes |
---|
| 670 | ///- the shortest path tree, |
---|
| 671 | ///- the distance of each node from the root. |
---|
| 672 | /// |
---|
| 673 | ///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 674 | ///\code |
---|
| 675 | /// b.init(); |
---|
| 676 | /// b.addSource(s); |
---|
| 677 | /// b.start(); |
---|
| 678 | ///\endcode |
---|
| 679 | void run(Node s) { |
---|
| 680 | init(); |
---|
| 681 | addSource(s); |
---|
| 682 | start(); |
---|
| 683 | } |
---|
[209] | 684 | |
---|
[100] | 685 | ///Finds the shortest path between \c s and \c t. |
---|
[209] | 686 | |
---|
[244] | 687 | ///This method runs the %BFS algorithm from node \c s |
---|
[286] | 688 | ///in order to compute the shortest path to node \c t |
---|
| 689 | ///(it stops searching when \c t is processed). |
---|
[100] | 690 | /// |
---|
[286] | 691 | ///\return \c true if \c t is reachable form \c s. |
---|
[244] | 692 | /// |
---|
| 693 | ///\note Apart from the return value, <tt>b.run(s,t)</tt> is just a |
---|
| 694 | ///shortcut of the following code. |
---|
[100] | 695 | ///\code |
---|
| 696 | /// b.init(); |
---|
| 697 | /// b.addSource(s); |
---|
| 698 | /// b.start(t); |
---|
| 699 | ///\endcode |
---|
[286] | 700 | bool run(Node s,Node t) { |
---|
[100] | 701 | init(); |
---|
| 702 | addSource(s); |
---|
| 703 | start(t); |
---|
[286] | 704 | return reached(t); |
---|
[100] | 705 | } |
---|
[209] | 706 | |
---|
[244] | 707 | ///Runs the algorithm to visit all nodes in the digraph. |
---|
| 708 | |
---|
| 709 | ///This method runs the %BFS algorithm in order to |
---|
| 710 | ///compute the shortest path to each node. |
---|
| 711 | /// |
---|
| 712 | ///The algorithm computes |
---|
| 713 | ///- the shortest path tree (forest), |
---|
| 714 | ///- the distance of each node from the root(s). |
---|
| 715 | /// |
---|
| 716 | ///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
| 717 | ///\code |
---|
| 718 | /// b.init(); |
---|
| 719 | /// for (NodeIt n(gr); n != INVALID; ++n) { |
---|
| 720 | /// if (!b.reached(n)) { |
---|
| 721 | /// b.addSource(n); |
---|
| 722 | /// b.start(); |
---|
| 723 | /// } |
---|
| 724 | /// } |
---|
| 725 | ///\endcode |
---|
| 726 | void run() { |
---|
| 727 | init(); |
---|
| 728 | for (NodeIt n(*G); n != INVALID; ++n) { |
---|
| 729 | if (!reached(n)) { |
---|
| 730 | addSource(n); |
---|
| 731 | start(); |
---|
| 732 | } |
---|
| 733 | } |
---|
| 734 | } |
---|
| 735 | |
---|
[100] | 736 | ///@} |
---|
| 737 | |
---|
| 738 | ///\name Query Functions |
---|
| 739 | ///The result of the %BFS algorithm can be obtained using these |
---|
| 740 | ///functions.\n |
---|
[244] | 741 | ///Either \ref lemon::Bfs::run() "run()" or \ref lemon::Bfs::start() |
---|
| 742 | ///"start()" must be called before using them. |
---|
[209] | 743 | |
---|
[100] | 744 | ///@{ |
---|
| 745 | |
---|
[244] | 746 | ///The shortest path to a node. |
---|
[100] | 747 | |
---|
[244] | 748 | ///Returns the shortest path to a node. |
---|
| 749 | /// |
---|
| 750 | ///\warning \c t should be reachable from the root(s). |
---|
| 751 | /// |
---|
| 752 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 753 | ///using this function. |
---|
| 754 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
[100] | 755 | |
---|
| 756 | ///The distance of a node from the root(s). |
---|
| 757 | |
---|
| 758 | ///Returns the distance of a node from the root(s). |
---|
[244] | 759 | /// |
---|
| 760 | ///\warning If node \c v is not reachable from the root(s), then |
---|
| 761 | ///the return value of this function is undefined. |
---|
| 762 | /// |
---|
| 763 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 764 | ///using this function. |
---|
[100] | 765 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 766 | |
---|
[244] | 767 | ///Returns the 'previous arc' of the shortest path tree for a node. |
---|
[100] | 768 | |
---|
[244] | 769 | ///This function returns the 'previous arc' of the shortest path |
---|
| 770 | ///tree for the node \c v, i.e. it returns the last arc of a |
---|
| 771 | ///shortest path from the root(s) to \c v. It is \c INVALID if \c v |
---|
| 772 | ///is not reachable from the root(s) or if \c v is a root. |
---|
| 773 | /// |
---|
| 774 | ///The shortest path tree used here is equal to the shortest path |
---|
| 775 | ///tree used in \ref predNode(). |
---|
| 776 | /// |
---|
| 777 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 778 | ///using this function. |
---|
[100] | 779 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 780 | |
---|
[244] | 781 | ///Returns the 'previous node' of the shortest path tree for a node. |
---|
[100] | 782 | |
---|
[244] | 783 | ///This function returns the 'previous node' of the shortest path |
---|
| 784 | ///tree for the node \c v, i.e. it returns the last but one node |
---|
| 785 | ///from a shortest path from the root(s) to \c v. It is \c INVALID |
---|
| 786 | ///if \c v is not reachable from the root(s) or if \c v is a root. |
---|
| 787 | /// |
---|
[100] | 788 | ///The shortest path tree used here is equal to the shortest path |
---|
| 789 | ///tree used in \ref predArc(). |
---|
[244] | 790 | /// |
---|
[100] | 791 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 792 | ///using this function. |
---|
| 793 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
[209] | 794 | G->source((*_pred)[v]); } |
---|
| 795 | |
---|
[244] | 796 | ///\brief Returns a const reference to the node map that stores the |
---|
| 797 | /// distances of the nodes. |
---|
| 798 | /// |
---|
| 799 | ///Returns a const reference to the node map that stores the distances |
---|
| 800 | ///of the nodes calculated by the algorithm. |
---|
| 801 | /// |
---|
| 802 | ///\pre Either \ref run() or \ref init() |
---|
| 803 | ///must be called before using this function. |
---|
[100] | 804 | const DistMap &distMap() const { return *_dist;} |
---|
[209] | 805 | |
---|
[244] | 806 | ///\brief Returns a const reference to the node map that stores the |
---|
| 807 | ///predecessor arcs. |
---|
| 808 | /// |
---|
| 809 | ///Returns a const reference to the node map that stores the predecessor |
---|
| 810 | ///arcs, which form the shortest path tree. |
---|
| 811 | /// |
---|
[100] | 812 | ///\pre Either \ref run() or \ref init() |
---|
| 813 | ///must be called before using this function. |
---|
| 814 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 815 | |
---|
[244] | 816 | ///Checks if a node is reachable from the root(s). |
---|
[100] | 817 | |
---|
[244] | 818 | ///Returns \c true if \c v is reachable from the root(s). |
---|
[100] | 819 | ///\pre Either \ref run() or \ref start() |
---|
| 820 | ///must be called before using this function. |
---|
[244] | 821 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[209] | 822 | |
---|
[100] | 823 | ///@} |
---|
| 824 | }; |
---|
| 825 | |
---|
[244] | 826 | ///Default traits class of bfs() function. |
---|
[100] | 827 | |
---|
[244] | 828 | ///Default traits class of bfs() function. |
---|
[157] | 829 | ///\tparam GR Digraph type. |
---|
[100] | 830 | template<class GR> |
---|
| 831 | struct BfsWizardDefaultTraits |
---|
| 832 | { |
---|
[244] | 833 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 834 | typedef GR Digraph; |
---|
[244] | 835 | |
---|
| 836 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 837 | ///arcs of the shortest paths. |
---|
[209] | 838 | /// |
---|
[244] | 839 | ///The type of the map that stores the predecessor |
---|
[100] | 840 | ///arcs of the shortest paths. |
---|
| 841 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 842 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
---|
[244] | 843 | ///Instantiates a \ref PredMap. |
---|
[209] | 844 | |
---|
| 845 | ///This function instantiates a \ref PredMap. |
---|
[244] | 846 | ///\param g is the digraph, to which we would like to define the |
---|
| 847 | ///\ref PredMap. |
---|
| 848 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 849 | { |
---|
[278] | 850 | return new PredMap(g); |
---|
[100] | 851 | } |
---|
| 852 | |
---|
| 853 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 854 | |
---|
[100] | 855 | ///The type of the map that indicates which nodes are processed. |
---|
| 856 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 857 | ///By default it is a NullMap. |
---|
[100] | 858 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[244] | 859 | ///Instantiates a \ref ProcessedMap. |
---|
[209] | 860 | |
---|
| 861 | ///This function instantiates a \ref ProcessedMap. |
---|
[100] | 862 | ///\param g is the digraph, to which |
---|
[244] | 863 | ///we would like to define the \ref ProcessedMap. |
---|
[100] | 864 | #ifdef DOXYGEN |
---|
[244] | 865 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 866 | #else |
---|
[244] | 867 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 868 | #endif |
---|
| 869 | { |
---|
| 870 | return new ProcessedMap(); |
---|
| 871 | } |
---|
[244] | 872 | |
---|
[100] | 873 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 874 | |
---|
[100] | 875 | ///The type of the map that indicates which nodes are reached. |
---|
[244] | 876 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 877 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[244] | 878 | ///Instantiates a \ref ReachedMap. |
---|
[209] | 879 | |
---|
| 880 | ///This function instantiates a \ref ReachedMap. |
---|
[244] | 881 | ///\param g is the digraph, to which |
---|
[100] | 882 | ///we would like to define the \ref ReachedMap. |
---|
[244] | 883 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 884 | { |
---|
[244] | 885 | return new ReachedMap(g); |
---|
[100] | 886 | } |
---|
[209] | 887 | |
---|
[244] | 888 | ///The type of the map that stores the distances of the nodes. |
---|
| 889 | |
---|
| 890 | ///The type of the map that stores the distances of the nodes. |
---|
[100] | 891 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[278] | 892 | typedef typename Digraph::template NodeMap<int> DistMap; |
---|
[244] | 893 | ///Instantiates a \ref DistMap. |
---|
[209] | 894 | |
---|
| 895 | ///This function instantiates a \ref DistMap. |
---|
[210] | 896 | ///\param g is the digraph, to which we would like to define |
---|
| 897 | ///the \ref DistMap |
---|
[244] | 898 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 899 | { |
---|
[278] | 900 | return new DistMap(g); |
---|
[100] | 901 | } |
---|
[278] | 902 | |
---|
| 903 | ///The type of the shortest paths. |
---|
| 904 | |
---|
| 905 | ///The type of the shortest paths. |
---|
| 906 | ///It must meet the \ref concepts::Path "Path" concept. |
---|
| 907 | typedef lemon::Path<Digraph> Path; |
---|
[100] | 908 | }; |
---|
[209] | 909 | |
---|
[244] | 910 | /// Default traits class used by \ref BfsWizard |
---|
[100] | 911 | |
---|
| 912 | /// To make it easier to use Bfs algorithm |
---|
[244] | 913 | /// we have created a wizard class. |
---|
[100] | 914 | /// This \ref BfsWizard class needs default traits, |
---|
[244] | 915 | /// as well as the \ref Bfs class. |
---|
[100] | 916 | /// The \ref BfsWizardBase is a class to be the default traits of the |
---|
| 917 | /// \ref BfsWizard class. |
---|
| 918 | template<class GR> |
---|
| 919 | class BfsWizardBase : public BfsWizardDefaultTraits<GR> |
---|
| 920 | { |
---|
| 921 | |
---|
| 922 | typedef BfsWizardDefaultTraits<GR> Base; |
---|
| 923 | protected: |
---|
[244] | 924 | //The type of the nodes in the digraph. |
---|
[100] | 925 | typedef typename Base::Digraph::Node Node; |
---|
| 926 | |
---|
[244] | 927 | //Pointer to the digraph the algorithm runs on. |
---|
[100] | 928 | void *_g; |
---|
[244] | 929 | //Pointer to the map of reached nodes. |
---|
[100] | 930 | void *_reached; |
---|
[244] | 931 | //Pointer to the map of processed nodes. |
---|
[100] | 932 | void *_processed; |
---|
[244] | 933 | //Pointer to the map of predecessors arcs. |
---|
[100] | 934 | void *_pred; |
---|
[244] | 935 | //Pointer to the map of distances. |
---|
[100] | 936 | void *_dist; |
---|
[278] | 937 | //Pointer to the shortest path to the target node. |
---|
| 938 | void *_path; |
---|
| 939 | //Pointer to the distance of the target node. |
---|
| 940 | int *_di; |
---|
[209] | 941 | |
---|
[100] | 942 | public: |
---|
| 943 | /// Constructor. |
---|
[209] | 944 | |
---|
[100] | 945 | /// This constructor does not require parameters, therefore it initiates |
---|
[278] | 946 | /// all of the attributes to \c 0. |
---|
[100] | 947 | BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[278] | 948 | _dist(0), _path(0), _di(0) {} |
---|
[100] | 949 | |
---|
| 950 | /// Constructor. |
---|
[209] | 951 | |
---|
[278] | 952 | /// This constructor requires one parameter, |
---|
| 953 | /// others are initiated to \c 0. |
---|
[244] | 954 | /// \param g The digraph the algorithm runs on. |
---|
[278] | 955 | BfsWizardBase(const GR &g) : |
---|
[209] | 956 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
---|
[278] | 957 | _reached(0), _processed(0), _pred(0), _dist(0), _path(0), _di(0) {} |
---|
[100] | 958 | |
---|
| 959 | }; |
---|
[209] | 960 | |
---|
[278] | 961 | /// Auxiliary class for the function-type interface of BFS algorithm. |
---|
[100] | 962 | |
---|
[278] | 963 | /// This auxiliary class is created to implement the |
---|
| 964 | /// \ref bfs() "function-type interface" of \ref Bfs algorithm. |
---|
| 965 | /// It does not have own \ref run() method, it uses the functions |
---|
| 966 | /// and features of the plain \ref Bfs. |
---|
[100] | 967 | /// |
---|
[278] | 968 | /// This class should only be used through the \ref bfs() function, |
---|
| 969 | /// which makes it easier to use the algorithm. |
---|
[100] | 970 | template<class TR> |
---|
| 971 | class BfsWizard : public TR |
---|
| 972 | { |
---|
| 973 | typedef TR Base; |
---|
| 974 | |
---|
[244] | 975 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 976 | typedef typename TR::Digraph Digraph; |
---|
[244] | 977 | |
---|
[100] | 978 | typedef typename Digraph::Node Node; |
---|
| 979 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 980 | typedef typename Digraph::Arc Arc; |
---|
| 981 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
[209] | 982 | |
---|
[244] | 983 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 984 | ///arcs of the shortest paths. |
---|
| 985 | typedef typename TR::PredMap PredMap; |
---|
[244] | 986 | ///\brief The type of the map that stores the distances of the nodes. |
---|
[100] | 987 | typedef typename TR::DistMap DistMap; |
---|
[244] | 988 | ///\brief The type of the map that indicates which nodes are reached. |
---|
| 989 | typedef typename TR::ReachedMap ReachedMap; |
---|
| 990 | ///\brief The type of the map that indicates which nodes are processed. |
---|
| 991 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
[278] | 992 | ///The type of the shortest paths |
---|
| 993 | typedef typename TR::Path Path; |
---|
[100] | 994 | |
---|
| 995 | public: |
---|
[244] | 996 | |
---|
[100] | 997 | /// Constructor. |
---|
| 998 | BfsWizard() : TR() {} |
---|
| 999 | |
---|
| 1000 | /// Constructor that requires parameters. |
---|
| 1001 | |
---|
| 1002 | /// Constructor that requires parameters. |
---|
| 1003 | /// These parameters will be the default values for the traits class. |
---|
[278] | 1004 | /// \param g The digraph the algorithm runs on. |
---|
| 1005 | BfsWizard(const Digraph &g) : |
---|
| 1006 | TR(g) {} |
---|
[100] | 1007 | |
---|
| 1008 | ///Copy constructor |
---|
| 1009 | BfsWizard(const TR &b) : TR(b) {} |
---|
| 1010 | |
---|
| 1011 | ~BfsWizard() {} |
---|
| 1012 | |
---|
[278] | 1013 | ///Runs BFS algorithm from the given source node. |
---|
[209] | 1014 | |
---|
[278] | 1015 | ///This method runs BFS algorithm from node \c s |
---|
| 1016 | ///in order to compute the shortest path to each node. |
---|
| 1017 | void run(Node s) |
---|
| 1018 | { |
---|
| 1019 | Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 1020 | if (Base::_pred) |
---|
| 1021 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 1022 | if (Base::_dist) |
---|
| 1023 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 1024 | if (Base::_reached) |
---|
| 1025 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 1026 | if (Base::_processed) |
---|
| 1027 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 1028 | if (s!=INVALID) |
---|
| 1029 | alg.run(s); |
---|
| 1030 | else |
---|
| 1031 | alg.run(); |
---|
| 1032 | } |
---|
| 1033 | |
---|
| 1034 | ///Finds the shortest path between \c s and \c t. |
---|
| 1035 | |
---|
| 1036 | ///This method runs BFS algorithm from node \c s |
---|
| 1037 | ///in order to compute the shortest path to node \c t |
---|
| 1038 | ///(it stops searching when \c t is processed). |
---|
| 1039 | /// |
---|
| 1040 | ///\return \c true if \c t is reachable form \c s. |
---|
| 1041 | bool run(Node s, Node t) |
---|
| 1042 | { |
---|
| 1043 | if (s==INVALID || t==INVALID) throw UninitializedParameter(); |
---|
| 1044 | Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 1045 | if (Base::_pred) |
---|
| 1046 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
| 1047 | if (Base::_dist) |
---|
| 1048 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 1049 | if (Base::_reached) |
---|
| 1050 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 1051 | if (Base::_processed) |
---|
| 1052 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
| 1053 | alg.run(s,t); |
---|
| 1054 | if (Base::_path) |
---|
| 1055 | *reinterpret_cast<Path*>(Base::_path) = alg.path(t); |
---|
| 1056 | if (Base::_di) |
---|
| 1057 | *Base::_di = alg.dist(t); |
---|
| 1058 | return alg.reached(t); |
---|
| 1059 | } |
---|
| 1060 | |
---|
| 1061 | ///Runs BFS algorithm to visit all nodes in the digraph. |
---|
| 1062 | |
---|
| 1063 | ///This method runs BFS algorithm in order to compute |
---|
| 1064 | ///the shortest path to each node. |
---|
[100] | 1065 | void run() |
---|
| 1066 | { |
---|
[278] | 1067 | run(INVALID); |
---|
[100] | 1068 | } |
---|
[209] | 1069 | |
---|
[244] | 1070 | template<class T> |
---|
[257] | 1071 | struct SetPredMapBase : public Base { |
---|
[244] | 1072 | typedef T PredMap; |
---|
| 1073 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
[257] | 1074 | SetPredMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1075 | }; |
---|
[278] | 1076 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1077 | ///for setting \ref PredMap object. |
---|
| 1078 | /// |
---|
[278] | 1079 | ///\ref named-func-param "Named parameter" |
---|
[244] | 1080 | ///for setting \ref PredMap object. |
---|
| 1081 | template<class T> |
---|
[257] | 1082 | BfsWizard<SetPredMapBase<T> > predMap(const T &t) |
---|
[244] | 1083 | { |
---|
| 1084 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1085 | return BfsWizard<SetPredMapBase<T> >(*this); |
---|
[244] | 1086 | } |
---|
| 1087 | |
---|
| 1088 | template<class T> |
---|
[257] | 1089 | struct SetReachedMapBase : public Base { |
---|
[244] | 1090 | typedef T ReachedMap; |
---|
| 1091 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
[257] | 1092 | SetReachedMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1093 | }; |
---|
[278] | 1094 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1095 | ///for setting \ref ReachedMap object. |
---|
| 1096 | /// |
---|
[278] | 1097 | /// \ref named-func-param "Named parameter" |
---|
[244] | 1098 | ///for setting \ref ReachedMap object. |
---|
| 1099 | template<class T> |
---|
[257] | 1100 | BfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
---|
[244] | 1101 | { |
---|
| 1102 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1103 | return BfsWizard<SetReachedMapBase<T> >(*this); |
---|
[244] | 1104 | } |
---|
| 1105 | |
---|
| 1106 | template<class T> |
---|
[278] | 1107 | struct SetDistMapBase : public Base { |
---|
| 1108 | typedef T DistMap; |
---|
| 1109 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
| 1110 | SetDistMapBase(const TR &b) : TR(b) {} |
---|
| 1111 | }; |
---|
| 1112 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1113 | ///for setting \ref DistMap object. |
---|
| 1114 | /// |
---|
| 1115 | /// \ref named-func-param "Named parameter" |
---|
| 1116 | ///for setting \ref DistMap object. |
---|
| 1117 | template<class T> |
---|
| 1118 | BfsWizard<SetDistMapBase<T> > distMap(const T &t) |
---|
| 1119 | { |
---|
| 1120 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1121 | return BfsWizard<SetDistMapBase<T> >(*this); |
---|
| 1122 | } |
---|
| 1123 | |
---|
| 1124 | template<class T> |
---|
[257] | 1125 | struct SetProcessedMapBase : public Base { |
---|
[244] | 1126 | typedef T ProcessedMap; |
---|
| 1127 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
[257] | 1128 | SetProcessedMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1129 | }; |
---|
[278] | 1130 | ///\brief \ref named-func-param "Named parameter" |
---|
[244] | 1131 | ///for setting \ref ProcessedMap object. |
---|
| 1132 | /// |
---|
[278] | 1133 | /// \ref named-func-param "Named parameter" |
---|
[244] | 1134 | ///for setting \ref ProcessedMap object. |
---|
| 1135 | template<class T> |
---|
[257] | 1136 | BfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
---|
[244] | 1137 | { |
---|
| 1138 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1139 | return BfsWizard<SetProcessedMapBase<T> >(*this); |
---|
[244] | 1140 | } |
---|
| 1141 | |
---|
| 1142 | template<class T> |
---|
[278] | 1143 | struct SetPathBase : public Base { |
---|
| 1144 | typedef T Path; |
---|
| 1145 | SetPathBase(const TR &b) : TR(b) {} |
---|
[244] | 1146 | }; |
---|
[278] | 1147 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1148 | ///for getting the shortest path to the target node. |
---|
[244] | 1149 | /// |
---|
[278] | 1150 | ///\ref named-func-param "Named parameter" |
---|
| 1151 | ///for getting the shortest path to the target node. |
---|
[244] | 1152 | template<class T> |
---|
[278] | 1153 | BfsWizard<SetPathBase<T> > path(const T &t) |
---|
[244] | 1154 | { |
---|
[278] | 1155 | Base::_path=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1156 | return BfsWizard<SetPathBase<T> >(*this); |
---|
| 1157 | } |
---|
| 1158 | |
---|
| 1159 | ///\brief \ref named-func-param "Named parameter" |
---|
| 1160 | ///for getting the distance of the target node. |
---|
| 1161 | /// |
---|
| 1162 | ///\ref named-func-param "Named parameter" |
---|
| 1163 | ///for getting the distance of the target node. |
---|
| 1164 | BfsWizard dist(const int &d) |
---|
| 1165 | { |
---|
| 1166 | Base::_di=const_cast<int*>(&d); |
---|
| 1167 | return *this; |
---|
[244] | 1168 | } |
---|
| 1169 | |
---|
[100] | 1170 | }; |
---|
[209] | 1171 | |
---|
[278] | 1172 | ///Function-type interface for BFS algorithm. |
---|
[100] | 1173 | |
---|
| 1174 | /// \ingroup search |
---|
[278] | 1175 | ///Function-type interface for BFS algorithm. |
---|
[100] | 1176 | /// |
---|
[278] | 1177 | ///This function also has several \ref named-func-param "named parameters", |
---|
[100] | 1178 | ///they are declared as the members of class \ref BfsWizard. |
---|
[278] | 1179 | ///The following examples show how to use these parameters. |
---|
[100] | 1180 | ///\code |
---|
[278] | 1181 | /// // Compute shortest path from node s to each node |
---|
| 1182 | /// bfs(g).predMap(preds).distMap(dists).run(s); |
---|
| 1183 | /// |
---|
| 1184 | /// // Compute shortest path from s to t |
---|
| 1185 | /// bool reached = bfs(g).path(p).dist(d).run(s,t); |
---|
[100] | 1186 | ///\endcode |
---|
| 1187 | ///\warning Don't forget to put the \ref BfsWizard::run() "run()" |
---|
| 1188 | ///to the end of the parameter list. |
---|
| 1189 | ///\sa BfsWizard |
---|
| 1190 | ///\sa Bfs |
---|
| 1191 | template<class GR> |
---|
| 1192 | BfsWizard<BfsWizardBase<GR> > |
---|
[278] | 1193 | bfs(const GR &digraph) |
---|
[100] | 1194 | { |
---|
[278] | 1195 | return BfsWizard<BfsWizardBase<GR> >(digraph); |
---|
[100] | 1196 | } |
---|
| 1197 | |
---|
| 1198 | #ifdef DOXYGEN |
---|
[244] | 1199 | /// \brief Visitor class for BFS. |
---|
[209] | 1200 | /// |
---|
[100] | 1201 | /// This class defines the interface of the BfsVisit events, and |
---|
[244] | 1202 | /// it could be the base of a real visitor class. |
---|
[100] | 1203 | template <typename _Digraph> |
---|
| 1204 | struct BfsVisitor { |
---|
| 1205 | typedef _Digraph Digraph; |
---|
| 1206 | typedef typename Digraph::Arc Arc; |
---|
| 1207 | typedef typename Digraph::Node Node; |
---|
[244] | 1208 | /// \brief Called for the source node(s) of the BFS. |
---|
[209] | 1209 | /// |
---|
[244] | 1210 | /// This function is called for the source node(s) of the BFS. |
---|
| 1211 | void start(const Node& node) {} |
---|
| 1212 | /// \brief Called when a node is reached first time. |
---|
| 1213 | /// |
---|
| 1214 | /// This function is called when a node is reached first time. |
---|
| 1215 | void reach(const Node& node) {} |
---|
| 1216 | /// \brief Called when a node is processed. |
---|
| 1217 | /// |
---|
| 1218 | /// This function is called when a node is processed. |
---|
| 1219 | void process(const Node& node) {} |
---|
| 1220 | /// \brief Called when an arc reaches a new node. |
---|
| 1221 | /// |
---|
| 1222 | /// This function is called when the BFS finds an arc whose target node |
---|
| 1223 | /// is not reached yet. |
---|
[100] | 1224 | void discover(const Arc& arc) {} |
---|
[244] | 1225 | /// \brief Called when an arc is examined but its target node is |
---|
[100] | 1226 | /// already discovered. |
---|
[209] | 1227 | /// |
---|
[244] | 1228 | /// This function is called when an arc is examined but its target node is |
---|
[100] | 1229 | /// already discovered. |
---|
| 1230 | void examine(const Arc& arc) {} |
---|
| 1231 | }; |
---|
| 1232 | #else |
---|
| 1233 | template <typename _Digraph> |
---|
| 1234 | struct BfsVisitor { |
---|
| 1235 | typedef _Digraph Digraph; |
---|
| 1236 | typedef typename Digraph::Arc Arc; |
---|
| 1237 | typedef typename Digraph::Node Node; |
---|
[244] | 1238 | void start(const Node&) {} |
---|
| 1239 | void reach(const Node&) {} |
---|
| 1240 | void process(const Node&) {} |
---|
[100] | 1241 | void discover(const Arc&) {} |
---|
| 1242 | void examine(const Arc&) {} |
---|
| 1243 | |
---|
| 1244 | template <typename _Visitor> |
---|
| 1245 | struct Constraints { |
---|
| 1246 | void constraints() { |
---|
[209] | 1247 | Arc arc; |
---|
| 1248 | Node node; |
---|
[244] | 1249 | visitor.start(node); |
---|
| 1250 | visitor.reach(node); |
---|
| 1251 | visitor.process(node); |
---|
[209] | 1252 | visitor.discover(arc); |
---|
| 1253 | visitor.examine(arc); |
---|
[100] | 1254 | } |
---|
| 1255 | _Visitor& visitor; |
---|
| 1256 | }; |
---|
| 1257 | }; |
---|
| 1258 | #endif |
---|
| 1259 | |
---|
| 1260 | /// \brief Default traits class of BfsVisit class. |
---|
| 1261 | /// |
---|
| 1262 | /// Default traits class of BfsVisit class. |
---|
[244] | 1263 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[100] | 1264 | template<class _Digraph> |
---|
| 1265 | struct BfsVisitDefaultTraits { |
---|
| 1266 | |
---|
[244] | 1267 | /// \brief The type of the digraph the algorithm runs on. |
---|
[100] | 1268 | typedef _Digraph Digraph; |
---|
| 1269 | |
---|
| 1270 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1271 | /// |
---|
[100] | 1272 | /// The type of the map that indicates which nodes are reached. |
---|
[244] | 1273 | /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 1274 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1275 | |
---|
[244] | 1276 | /// \brief Instantiates a \ref ReachedMap. |
---|
[100] | 1277 | /// |
---|
[209] | 1278 | /// This function instantiates a \ref ReachedMap. |
---|
[100] | 1279 | /// \param digraph is the digraph, to which |
---|
| 1280 | /// we would like to define the \ref ReachedMap. |
---|
| 1281 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1282 | return new ReachedMap(digraph); |
---|
| 1283 | } |
---|
| 1284 | |
---|
| 1285 | }; |
---|
| 1286 | |
---|
| 1287 | /// \ingroup search |
---|
[209] | 1288 | /// |
---|
[244] | 1289 | /// \brief %BFS algorithm class with visitor interface. |
---|
[209] | 1290 | /// |
---|
[100] | 1291 | /// This class provides an efficient implementation of the %BFS algorithm |
---|
| 1292 | /// with visitor interface. |
---|
| 1293 | /// |
---|
| 1294 | /// The %BfsVisit class provides an alternative interface to the Bfs |
---|
| 1295 | /// class. It works with callback mechanism, the BfsVisit object calls |
---|
[244] | 1296 | /// the member functions of the \c Visitor class on every BFS event. |
---|
[100] | 1297 | /// |
---|
[252] | 1298 | /// This interface of the BFS algorithm should be used in special cases |
---|
| 1299 | /// when extra actions have to be performed in connection with certain |
---|
| 1300 | /// events of the BFS algorithm. Otherwise consider to use Bfs or bfs() |
---|
| 1301 | /// instead. |
---|
| 1302 | /// |
---|
[244] | 1303 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[210] | 1304 | /// The default value is |
---|
[244] | 1305 | /// \ref ListDigraph. The value of _Digraph is not used directly by |
---|
| 1306 | /// \ref BfsVisit, it is only passed to \ref BfsVisitDefaultTraits. |
---|
| 1307 | /// \tparam _Visitor The Visitor type that is used by the algorithm. |
---|
| 1308 | /// \ref BfsVisitor "BfsVisitor<_Digraph>" is an empty visitor, which |
---|
| 1309 | /// does not observe the BFS events. If you want to observe the BFS |
---|
| 1310 | /// events, you should implement your own visitor class. |
---|
[209] | 1311 | /// \tparam _Traits Traits class to set various data types used by the |
---|
[100] | 1312 | /// algorithm. The default traits class is |
---|
| 1313 | /// \ref BfsVisitDefaultTraits "BfsVisitDefaultTraits<_Digraph>". |
---|
| 1314 | /// See \ref BfsVisitDefaultTraits for the documentation of |
---|
[244] | 1315 | /// a BFS visit traits class. |
---|
[100] | 1316 | #ifdef DOXYGEN |
---|
| 1317 | template <typename _Digraph, typename _Visitor, typename _Traits> |
---|
| 1318 | #else |
---|
| 1319 | template <typename _Digraph = ListDigraph, |
---|
[209] | 1320 | typename _Visitor = BfsVisitor<_Digraph>, |
---|
| 1321 | typename _Traits = BfsDefaultTraits<_Digraph> > |
---|
[100] | 1322 | #endif |
---|
| 1323 | class BfsVisit { |
---|
| 1324 | public: |
---|
[209] | 1325 | |
---|
[100] | 1326 | /// \brief \ref Exception for uninitialized parameters. |
---|
| 1327 | /// |
---|
| 1328 | /// This error represents problems in the initialization |
---|
[244] | 1329 | /// of the parameters of the algorithm. |
---|
[100] | 1330 | class UninitializedParameter : public lemon::UninitializedParameter { |
---|
| 1331 | public: |
---|
[209] | 1332 | virtual const char* what() const throw() |
---|
[100] | 1333 | { |
---|
[209] | 1334 | return "lemon::BfsVisit::UninitializedParameter"; |
---|
[100] | 1335 | } |
---|
| 1336 | }; |
---|
| 1337 | |
---|
[244] | 1338 | ///The traits class. |
---|
[100] | 1339 | typedef _Traits Traits; |
---|
| 1340 | |
---|
[244] | 1341 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 1342 | typedef typename Traits::Digraph Digraph; |
---|
| 1343 | |
---|
[244] | 1344 | ///The visitor type used by the algorithm. |
---|
[100] | 1345 | typedef _Visitor Visitor; |
---|
| 1346 | |
---|
[244] | 1347 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 1348 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1349 | |
---|
| 1350 | private: |
---|
| 1351 | |
---|
| 1352 | typedef typename Digraph::Node Node; |
---|
| 1353 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1354 | typedef typename Digraph::Arc Arc; |
---|
| 1355 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1356 | |
---|
[244] | 1357 | //Pointer to the underlying digraph. |
---|
[100] | 1358 | const Digraph *_digraph; |
---|
[244] | 1359 | //Pointer to the visitor object. |
---|
[100] | 1360 | Visitor *_visitor; |
---|
[244] | 1361 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 1362 | ReachedMap *_reached; |
---|
[244] | 1363 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 1364 | bool local_reached; |
---|
| 1365 | |
---|
| 1366 | std::vector<typename Digraph::Node> _list; |
---|
| 1367 | int _list_front, _list_back; |
---|
| 1368 | |
---|
[280] | 1369 | //Creates the maps if necessary. |
---|
[100] | 1370 | void create_maps() { |
---|
| 1371 | if(!_reached) { |
---|
[209] | 1372 | local_reached = true; |
---|
| 1373 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1374 | } |
---|
| 1375 | } |
---|
| 1376 | |
---|
| 1377 | protected: |
---|
| 1378 | |
---|
| 1379 | BfsVisit() {} |
---|
[209] | 1380 | |
---|
[100] | 1381 | public: |
---|
| 1382 | |
---|
| 1383 | typedef BfsVisit Create; |
---|
| 1384 | |
---|
| 1385 | /// \name Named template parameters |
---|
| 1386 | |
---|
| 1387 | ///@{ |
---|
| 1388 | template <class T> |
---|
[257] | 1389 | struct SetReachedMapTraits : public Traits { |
---|
[100] | 1390 | typedef T ReachedMap; |
---|
| 1391 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
[209] | 1392 | throw UninitializedParameter(); |
---|
[100] | 1393 | } |
---|
| 1394 | }; |
---|
[209] | 1395 | /// \brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 1396 | /// ReachedMap type. |
---|
[100] | 1397 | /// |
---|
[244] | 1398 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
---|
[100] | 1399 | template <class T> |
---|
[257] | 1400 | struct SetReachedMap : public BfsVisit< Digraph, Visitor, |
---|
| 1401 | SetReachedMapTraits<T> > { |
---|
| 1402 | typedef BfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
---|
[100] | 1403 | }; |
---|
| 1404 | ///@} |
---|
| 1405 | |
---|
[209] | 1406 | public: |
---|
| 1407 | |
---|
[100] | 1408 | /// \brief Constructor. |
---|
| 1409 | /// |
---|
| 1410 | /// Constructor. |
---|
| 1411 | /// |
---|
[244] | 1412 | /// \param digraph The digraph the algorithm runs on. |
---|
| 1413 | /// \param visitor The visitor object of the algorithm. |
---|
[209] | 1414 | BfsVisit(const Digraph& digraph, Visitor& visitor) |
---|
[100] | 1415 | : _digraph(&digraph), _visitor(&visitor), |
---|
[209] | 1416 | _reached(0), local_reached(false) {} |
---|
| 1417 | |
---|
[100] | 1418 | /// \brief Destructor. |
---|
| 1419 | ~BfsVisit() { |
---|
| 1420 | if(local_reached) delete _reached; |
---|
| 1421 | } |
---|
| 1422 | |
---|
[244] | 1423 | /// \brief Sets the map that indicates which nodes are reached. |
---|
[100] | 1424 | /// |
---|
[244] | 1425 | /// Sets the map that indicates which nodes are reached. |
---|
[100] | 1426 | /// If you don't use this function before calling \ref run(), |
---|
[244] | 1427 | /// it will allocate one. The destructor deallocates this |
---|
[100] | 1428 | /// automatically allocated map, of course. |
---|
| 1429 | /// \return <tt> (*this) </tt> |
---|
| 1430 | BfsVisit &reachedMap(ReachedMap &m) { |
---|
| 1431 | if(local_reached) { |
---|
[209] | 1432 | delete _reached; |
---|
| 1433 | local_reached = false; |
---|
[100] | 1434 | } |
---|
| 1435 | _reached = &m; |
---|
| 1436 | return *this; |
---|
| 1437 | } |
---|
| 1438 | |
---|
| 1439 | public: |
---|
[244] | 1440 | |
---|
[100] | 1441 | /// \name Execution control |
---|
| 1442 | /// The simplest way to execute the algorithm is to use |
---|
[244] | 1443 | /// one of the member functions called \ref lemon::BfsVisit::run() |
---|
| 1444 | /// "run()". |
---|
[100] | 1445 | /// \n |
---|
[244] | 1446 | /// If you need more control on the execution, first you must call |
---|
| 1447 | /// \ref lemon::BfsVisit::init() "init()", then you can add several |
---|
| 1448 | /// source nodes with \ref lemon::BfsVisit::addSource() "addSource()". |
---|
| 1449 | /// Finally \ref lemon::BfsVisit::start() "start()" will perform the |
---|
| 1450 | /// actual path computation. |
---|
[100] | 1451 | |
---|
| 1452 | /// @{ |
---|
[244] | 1453 | |
---|
[100] | 1454 | /// \brief Initializes the internal data structures. |
---|
| 1455 | /// |
---|
| 1456 | /// Initializes the internal data structures. |
---|
| 1457 | void init() { |
---|
| 1458 | create_maps(); |
---|
| 1459 | _list.resize(countNodes(*_digraph)); |
---|
| 1460 | _list_front = _list_back = -1; |
---|
| 1461 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
---|
[209] | 1462 | _reached->set(u, false); |
---|
[100] | 1463 | } |
---|
| 1464 | } |
---|
[209] | 1465 | |
---|
[100] | 1466 | /// \brief Adds a new source node. |
---|
| 1467 | /// |
---|
| 1468 | /// Adds a new source node to the set of nodes to be processed. |
---|
| 1469 | void addSource(Node s) { |
---|
| 1470 | if(!(*_reached)[s]) { |
---|
[209] | 1471 | _reached->set(s,true); |
---|
| 1472 | _visitor->start(s); |
---|
| 1473 | _visitor->reach(s); |
---|
[100] | 1474 | _list[++_list_back] = s; |
---|
[209] | 1475 | } |
---|
[100] | 1476 | } |
---|
[209] | 1477 | |
---|
[100] | 1478 | /// \brief Processes the next node. |
---|
| 1479 | /// |
---|
| 1480 | /// Processes the next node. |
---|
| 1481 | /// |
---|
| 1482 | /// \return The processed node. |
---|
| 1483 | /// |
---|
[244] | 1484 | /// \pre The queue must not be empty. |
---|
[209] | 1485 | Node processNextNode() { |
---|
[100] | 1486 | Node n = _list[++_list_front]; |
---|
| 1487 | _visitor->process(n); |
---|
| 1488 | Arc e; |
---|
| 1489 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1490 | Node m = _digraph->target(e); |
---|
| 1491 | if (!(*_reached)[m]) { |
---|
| 1492 | _visitor->discover(e); |
---|
| 1493 | _visitor->reach(m); |
---|
| 1494 | _reached->set(m, true); |
---|
| 1495 | _list[++_list_back] = m; |
---|
| 1496 | } else { |
---|
| 1497 | _visitor->examine(e); |
---|
| 1498 | } |
---|
| 1499 | } |
---|
| 1500 | return n; |
---|
| 1501 | } |
---|
| 1502 | |
---|
| 1503 | /// \brief Processes the next node. |
---|
| 1504 | /// |
---|
[244] | 1505 | /// Processes the next node and checks if the given target node |
---|
[100] | 1506 | /// is reached. If the target node is reachable from the processed |
---|
[244] | 1507 | /// node, then the \c reach parameter will be set to \c true. |
---|
[100] | 1508 | /// |
---|
| 1509 | /// \param target The target node. |
---|
[244] | 1510 | /// \retval reach Indicates if the target node is reached. |
---|
| 1511 | /// It should be initially \c false. |
---|
| 1512 | /// |
---|
[100] | 1513 | /// \return The processed node. |
---|
| 1514 | /// |
---|
[244] | 1515 | /// \pre The queue must not be empty. |
---|
[100] | 1516 | Node processNextNode(Node target, bool& reach) { |
---|
| 1517 | Node n = _list[++_list_front]; |
---|
| 1518 | _visitor->process(n); |
---|
| 1519 | Arc e; |
---|
| 1520 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1521 | Node m = _digraph->target(e); |
---|
| 1522 | if (!(*_reached)[m]) { |
---|
| 1523 | _visitor->discover(e); |
---|
| 1524 | _visitor->reach(m); |
---|
| 1525 | _reached->set(m, true); |
---|
| 1526 | _list[++_list_back] = m; |
---|
| 1527 | reach = reach || (target == m); |
---|
| 1528 | } else { |
---|
| 1529 | _visitor->examine(e); |
---|
| 1530 | } |
---|
| 1531 | } |
---|
| 1532 | return n; |
---|
| 1533 | } |
---|
| 1534 | |
---|
| 1535 | /// \brief Processes the next node. |
---|
| 1536 | /// |
---|
[244] | 1537 | /// Processes the next node and checks if at least one of reached |
---|
| 1538 | /// nodes has \c true value in the \c nm node map. If one node |
---|
| 1539 | /// with \c true value is reachable from the processed node, then the |
---|
| 1540 | /// \c rnode parameter will be set to the first of such nodes. |
---|
[100] | 1541 | /// |
---|
[244] | 1542 | /// \param nm A \c bool (or convertible) node map that indicates the |
---|
| 1543 | /// possible targets. |
---|
[100] | 1544 | /// \retval rnode The reached target node. |
---|
[244] | 1545 | /// It should be initially \c INVALID. |
---|
| 1546 | /// |
---|
[100] | 1547 | /// \return The processed node. |
---|
| 1548 | /// |
---|
[244] | 1549 | /// \pre The queue must not be empty. |
---|
[100] | 1550 | template <typename NM> |
---|
| 1551 | Node processNextNode(const NM& nm, Node& rnode) { |
---|
| 1552 | Node n = _list[++_list_front]; |
---|
| 1553 | _visitor->process(n); |
---|
| 1554 | Arc e; |
---|
| 1555 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1556 | Node m = _digraph->target(e); |
---|
| 1557 | if (!(*_reached)[m]) { |
---|
| 1558 | _visitor->discover(e); |
---|
| 1559 | _visitor->reach(m); |
---|
| 1560 | _reached->set(m, true); |
---|
| 1561 | _list[++_list_back] = m; |
---|
| 1562 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 1563 | } else { |
---|
| 1564 | _visitor->examine(e); |
---|
| 1565 | } |
---|
| 1566 | } |
---|
| 1567 | return n; |
---|
| 1568 | } |
---|
| 1569 | |
---|
[244] | 1570 | /// \brief The next node to be processed. |
---|
[100] | 1571 | /// |
---|
[244] | 1572 | /// Returns the next node to be processed or \c INVALID if the queue |
---|
| 1573 | /// is empty. |
---|
| 1574 | Node nextNode() const { |
---|
[100] | 1575 | return _list_front != _list_back ? _list[_list_front + 1] : INVALID; |
---|
| 1576 | } |
---|
| 1577 | |
---|
| 1578 | /// \brief Returns \c false if there are nodes |
---|
[244] | 1579 | /// to be processed. |
---|
[100] | 1580 | /// |
---|
| 1581 | /// Returns \c false if there are nodes |
---|
[244] | 1582 | /// to be processed in the queue. |
---|
| 1583 | bool emptyQueue() const { return _list_front == _list_back; } |
---|
[100] | 1584 | |
---|
| 1585 | /// \brief Returns the number of the nodes to be processed. |
---|
| 1586 | /// |
---|
| 1587 | /// Returns the number of the nodes to be processed in the queue. |
---|
[244] | 1588 | int queueSize() const { return _list_back - _list_front; } |
---|
[209] | 1589 | |
---|
[100] | 1590 | /// \brief Executes the algorithm. |
---|
| 1591 | /// |
---|
| 1592 | /// Executes the algorithm. |
---|
| 1593 | /// |
---|
[244] | 1594 | /// This method runs the %BFS algorithm from the root node(s) |
---|
| 1595 | /// in order to compute the shortest path to each node. |
---|
| 1596 | /// |
---|
| 1597 | /// The algorithm computes |
---|
| 1598 | /// - the shortest path tree (forest), |
---|
| 1599 | /// - the distance of each node from the root(s). |
---|
| 1600 | /// |
---|
| 1601 | /// \pre init() must be called and at least one root node should be added |
---|
[100] | 1602 | /// with addSource() before using this function. |
---|
[244] | 1603 | /// |
---|
| 1604 | /// \note <tt>b.start()</tt> is just a shortcut of the following code. |
---|
| 1605 | /// \code |
---|
| 1606 | /// while ( !b.emptyQueue() ) { |
---|
| 1607 | /// b.processNextNode(); |
---|
| 1608 | /// } |
---|
| 1609 | /// \endcode |
---|
[100] | 1610 | void start() { |
---|
| 1611 | while ( !emptyQueue() ) processNextNode(); |
---|
| 1612 | } |
---|
[209] | 1613 | |
---|
[244] | 1614 | /// \brief Executes the algorithm until the given target node is reached. |
---|
[100] | 1615 | /// |
---|
[244] | 1616 | /// Executes the algorithm until the given target node is reached. |
---|
[100] | 1617 | /// |
---|
[244] | 1618 | /// This method runs the %BFS algorithm from the root node(s) |
---|
[286] | 1619 | /// in order to compute the shortest path to \c t. |
---|
[244] | 1620 | /// |
---|
| 1621 | /// The algorithm computes |
---|
[286] | 1622 | /// - the shortest path to \c t, |
---|
| 1623 | /// - the distance of \c t from the root(s). |
---|
[244] | 1624 | /// |
---|
| 1625 | /// \pre init() must be called and at least one root node should be |
---|
| 1626 | /// added with addSource() before using this function. |
---|
| 1627 | /// |
---|
| 1628 | /// \note <tt>b.start(t)</tt> is just a shortcut of the following code. |
---|
| 1629 | /// \code |
---|
| 1630 | /// bool reach = false; |
---|
| 1631 | /// while ( !b.emptyQueue() && !reach ) { |
---|
| 1632 | /// b.processNextNode(t, reach); |
---|
| 1633 | /// } |
---|
| 1634 | /// \endcode |
---|
[286] | 1635 | void start(Node t) { |
---|
[100] | 1636 | bool reach = false; |
---|
[286] | 1637 | while ( !emptyQueue() && !reach ) processNextNode(t, reach); |
---|
[100] | 1638 | } |
---|
[209] | 1639 | |
---|
[100] | 1640 | /// \brief Executes the algorithm until a condition is met. |
---|
| 1641 | /// |
---|
| 1642 | /// Executes the algorithm until a condition is met. |
---|
| 1643 | /// |
---|
[244] | 1644 | /// This method runs the %BFS algorithm from the root node(s) in |
---|
| 1645 | /// order to compute the shortest path to a node \c v with |
---|
| 1646 | /// <tt>nm[v]</tt> true, if such a node can be found. |
---|
[100] | 1647 | /// |
---|
[244] | 1648 | /// \param nm must be a bool (or convertible) node map. The |
---|
| 1649 | /// algorithm will stop when it reaches a node \c v with |
---|
[100] | 1650 | /// <tt>nm[v]</tt> true. |
---|
| 1651 | /// |
---|
[244] | 1652 | /// \return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 1653 | /// \c INVALID if no such node was found. |
---|
| 1654 | /// |
---|
| 1655 | /// \pre init() must be called and at least one root node should be |
---|
| 1656 | /// added with addSource() before using this function. |
---|
| 1657 | /// |
---|
| 1658 | /// \note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
---|
| 1659 | /// \code |
---|
| 1660 | /// Node rnode = INVALID; |
---|
| 1661 | /// while ( !b.emptyQueue() && rnode == INVALID ) { |
---|
| 1662 | /// b.processNextNode(nm, rnode); |
---|
| 1663 | /// } |
---|
| 1664 | /// return rnode; |
---|
| 1665 | /// \endcode |
---|
[100] | 1666 | template <typename NM> |
---|
| 1667 | Node start(const NM &nm) { |
---|
| 1668 | Node rnode = INVALID; |
---|
| 1669 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 1670 | processNextNode(nm, rnode); |
---|
[100] | 1671 | } |
---|
| 1672 | return rnode; |
---|
| 1673 | } |
---|
| 1674 | |
---|
[286] | 1675 | /// \brief Runs the algorithm from the given source node. |
---|
[100] | 1676 | /// |
---|
[244] | 1677 | /// This method runs the %BFS algorithm from node \c s |
---|
| 1678 | /// in order to compute the shortest path to each node. |
---|
| 1679 | /// |
---|
| 1680 | /// The algorithm computes |
---|
| 1681 | /// - the shortest path tree, |
---|
| 1682 | /// - the distance of each node from the root. |
---|
| 1683 | /// |
---|
| 1684 | /// \note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1685 | ///\code |
---|
| 1686 | /// b.init(); |
---|
| 1687 | /// b.addSource(s); |
---|
| 1688 | /// b.start(); |
---|
| 1689 | ///\endcode |
---|
| 1690 | void run(Node s) { |
---|
| 1691 | init(); |
---|
| 1692 | addSource(s); |
---|
| 1693 | start(); |
---|
| 1694 | } |
---|
| 1695 | |
---|
[286] | 1696 | /// \brief Finds the shortest path between \c s and \c t. |
---|
| 1697 | /// |
---|
| 1698 | /// This method runs the %BFS algorithm from node \c s |
---|
| 1699 | /// in order to compute the shortest path to node \c t |
---|
| 1700 | /// (it stops searching when \c t is processed). |
---|
| 1701 | /// |
---|
| 1702 | /// \return \c true if \c t is reachable form \c s. |
---|
| 1703 | /// |
---|
| 1704 | /// \note Apart from the return value, <tt>b.run(s,t)</tt> is just a |
---|
| 1705 | /// shortcut of the following code. |
---|
| 1706 | ///\code |
---|
| 1707 | /// b.init(); |
---|
| 1708 | /// b.addSource(s); |
---|
| 1709 | /// b.start(t); |
---|
| 1710 | ///\endcode |
---|
| 1711 | bool run(Node s,Node t) { |
---|
| 1712 | init(); |
---|
| 1713 | addSource(s); |
---|
| 1714 | start(t); |
---|
| 1715 | return reached(t); |
---|
| 1716 | } |
---|
| 1717 | |
---|
[244] | 1718 | /// \brief Runs the algorithm to visit all nodes in the digraph. |
---|
[209] | 1719 | /// |
---|
[100] | 1720 | /// This method runs the %BFS algorithm in order to |
---|
[244] | 1721 | /// compute the shortest path to each node. |
---|
[100] | 1722 | /// |
---|
[244] | 1723 | /// The algorithm computes |
---|
| 1724 | /// - the shortest path tree (forest), |
---|
| 1725 | /// - the distance of each node from the root(s). |
---|
| 1726 | /// |
---|
| 1727 | /// \note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1728 | ///\code |
---|
| 1729 | /// b.init(); |
---|
[244] | 1730 | /// for (NodeIt n(gr); n != INVALID; ++n) { |
---|
| 1731 | /// if (!b.reached(n)) { |
---|
| 1732 | /// b.addSource(n); |
---|
[100] | 1733 | /// b.start(); |
---|
| 1734 | /// } |
---|
| 1735 | /// } |
---|
| 1736 | ///\endcode |
---|
| 1737 | void run() { |
---|
| 1738 | init(); |
---|
| 1739 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
| 1740 | if (!reached(it)) { |
---|
| 1741 | addSource(it); |
---|
| 1742 | start(); |
---|
| 1743 | } |
---|
| 1744 | } |
---|
| 1745 | } |
---|
[244] | 1746 | |
---|
[100] | 1747 | ///@} |
---|
| 1748 | |
---|
| 1749 | /// \name Query Functions |
---|
| 1750 | /// The result of the %BFS algorithm can be obtained using these |
---|
| 1751 | /// functions.\n |
---|
[244] | 1752 | /// Either \ref lemon::BfsVisit::run() "run()" or |
---|
| 1753 | /// \ref lemon::BfsVisit::start() "start()" must be called before |
---|
| 1754 | /// using them. |
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[100] | 1755 | ///@{ |
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| 1756 | |
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[244] | 1757 | /// \brief Checks if a node is reachable from the root(s). |
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[100] | 1758 | /// |
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| 1759 | /// Returns \c true if \c v is reachable from the root(s). |
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| 1760 | /// \pre Either \ref run() or \ref start() |
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| 1761 | /// must be called before using this function. |
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| 1762 | bool reached(Node v) { return (*_reached)[v]; } |
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[244] | 1763 | |
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[100] | 1764 | ///@} |
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[244] | 1765 | |
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[100] | 1766 | }; |
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| 1767 | |
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| 1768 | } //END OF NAMESPACE LEMON |
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| 1769 | |
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| 1770 | #endif |
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