[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/graph_utils.h> |
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| 28 | #include <lemon/bits/path_dump.h> |
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| 29 | #include <lemon/bits/invalid.h> |
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| 30 | #include <lemon/error.h> |
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| 31 | #include <lemon/maps.h> |
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| 32 | |
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| 33 | namespace lemon { |
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| 34 | |
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| 35 | ///Default traits class of Bfs class. |
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| 36 | |
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| 37 | ///Default traits class of Bfs class. |
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[157] | 38 | ///\tparam GR Digraph type. |
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[100] | 39 | template<class GR> |
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| 40 | struct BfsDefaultTraits |
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| 41 | { |
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[244] | 42 | ///The type of the digraph the algorithm runs on. |
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[100] | 43 | typedef GR Digraph; |
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[244] | 44 | |
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| 45 | ///\brief The type of the map that stores the predecessor |
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[100] | 46 | ///arcs of the shortest paths. |
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[209] | 47 | /// |
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[244] | 48 | ///The type of the map that stores the predecessor |
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[100] | 49 | ///arcs of the shortest paths. |
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| 50 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[244] | 51 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
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| 52 | ///Instantiates a \ref PredMap. |
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[209] | 53 | |
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| 54 | ///This function instantiates a \ref PredMap. |
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[244] | 55 | ///\param g is the digraph, to which we would like to define the |
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| 56 | ///\ref PredMap. |
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[100] | 57 | ///\todo The digraph alone may be insufficient to initialize |
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[244] | 58 | static PredMap *createPredMap(const Digraph &g) |
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[100] | 59 | { |
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[244] | 60 | return new PredMap(g); |
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[100] | 61 | } |
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[244] | 62 | |
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[100] | 63 | ///The type of the map that indicates which nodes are processed. |
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[209] | 64 | |
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[100] | 65 | ///The type of the map that indicates which nodes are processed. |
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| 66 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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[244] | 67 | ///By default it is a NullMap. |
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[100] | 68 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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[244] | 69 | ///Instantiates a \ref ProcessedMap. |
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[209] | 70 | |
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| 71 | ///This function instantiates a \ref ProcessedMap. |
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[100] | 72 | ///\param g is the digraph, to which |
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| 73 | ///we would like to define the \ref ProcessedMap |
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| 74 | #ifdef DOXYGEN |
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[244] | 75 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 76 | #else |
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[244] | 77 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 78 | #endif |
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| 79 | { |
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| 80 | return new ProcessedMap(); |
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| 81 | } |
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[244] | 82 | |
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[100] | 83 | ///The type of the map that indicates which nodes are reached. |
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[209] | 84 | |
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[100] | 85 | ///The type of the map that indicates which nodes are reached. |
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[244] | 86 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
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[100] | 87 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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[244] | 88 | ///Instantiates a \ref ReachedMap. |
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[209] | 89 | |
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| 90 | ///This function instantiates a \ref ReachedMap. |
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[244] | 91 | ///\param g is the digraph, to which |
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[100] | 92 | ///we would like to define the \ref ReachedMap. |
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[244] | 93 | static ReachedMap *createReachedMap(const Digraph &g) |
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[100] | 94 | { |
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[244] | 95 | return new ReachedMap(g); |
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[100] | 96 | } |
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[209] | 97 | |
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[244] | 98 | ///The type of the map that stores the distances of the nodes. |
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| 99 | |
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| 100 | ///The type of the map that stores the distances of the nodes. |
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[100] | 101 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 102 | typedef typename Digraph::template NodeMap<int> DistMap; |
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[244] | 103 | ///Instantiates a \ref DistMap. |
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[209] | 104 | |
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| 105 | ///This function instantiates a \ref DistMap. |
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[244] | 106 | ///\param g is the digraph, to which we would like to define the |
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| 107 | ///\ref DistMap. |
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| 108 | static DistMap *createDistMap(const Digraph &g) |
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[100] | 109 | { |
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[244] | 110 | return new DistMap(g); |
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[100] | 111 | } |
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| 112 | }; |
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[209] | 113 | |
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[100] | 114 | ///%BFS algorithm class. |
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[209] | 115 | |
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[100] | 116 | ///\ingroup search |
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| 117 | ///This class provides an efficient implementation of the %BFS algorithm. |
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| 118 | /// |
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[244] | 119 | ///There is also a \ref bfs() "function type interface" for the BFS |
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| 120 | ///algorithm, which is convenient in the simplier cases and it can be |
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| 121 | ///used easier. |
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| 122 | /// |
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| 123 | ///\tparam GR The type of the digraph the algorithm runs on. |
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| 124 | ///The default value is \ref ListDigraph. The value of GR is not used |
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| 125 | ///directly by \ref Bfs, it is only passed to \ref BfsDefaultTraits. |
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[157] | 126 | ///\tparam TR Traits class to set various data types used by the algorithm. |
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[100] | 127 | ///The default traits class is |
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| 128 | ///\ref BfsDefaultTraits "BfsDefaultTraits<GR>". |
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| 129 | ///See \ref BfsDefaultTraits for the documentation of |
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| 130 | ///a Bfs traits class. |
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| 131 | #ifdef DOXYGEN |
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| 132 | template <typename GR, |
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[209] | 133 | typename TR> |
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[100] | 134 | #else |
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| 135 | template <typename GR=ListDigraph, |
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[209] | 136 | typename TR=BfsDefaultTraits<GR> > |
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[100] | 137 | #endif |
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| 138 | class Bfs { |
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| 139 | public: |
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[244] | 140 | ///\ref Exception for uninitialized parameters. |
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| 141 | |
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| 142 | ///This error represents problems in the initialization of the |
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| 143 | ///parameters of the algorithm. |
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[100] | 144 | class UninitializedParameter : public lemon::UninitializedParameter { |
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| 145 | public: |
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| 146 | virtual const char* what() const throw() { |
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[209] | 147 | return "lemon::Bfs::UninitializedParameter"; |
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[100] | 148 | } |
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| 149 | }; |
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| 150 | |
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[244] | 151 | ///The type of the digraph the algorithm runs on. |
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[100] | 152 | typedef typename TR::Digraph Digraph; |
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[209] | 153 | |
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[244] | 154 | ///\brief The type of the map that stores the predecessor arcs of the |
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| 155 | ///shortest paths. |
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[100] | 156 | typedef typename TR::PredMap PredMap; |
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[244] | 157 | ///The type of the map that stores the distances of the nodes. |
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| 158 | typedef typename TR::DistMap DistMap; |
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| 159 | ///The type of the map that indicates which nodes are reached. |
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[100] | 160 | typedef typename TR::ReachedMap ReachedMap; |
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[244] | 161 | ///The type of the map that indicates which nodes are processed. |
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[100] | 162 | typedef typename TR::ProcessedMap ProcessedMap; |
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[244] | 163 | ///The type of the paths. |
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| 164 | typedef PredMapPath<Digraph, PredMap> Path; |
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| 165 | |
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| 166 | ///The traits class. |
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| 167 | typedef TR Traits; |
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| 168 | |
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[100] | 169 | private: |
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| 170 | |
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| 171 | typedef typename Digraph::Node Node; |
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| 172 | typedef typename Digraph::NodeIt NodeIt; |
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| 173 | typedef typename Digraph::Arc Arc; |
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| 174 | typedef typename Digraph::OutArcIt OutArcIt; |
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| 175 | |
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[244] | 176 | //Pointer to the underlying digraph. |
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[100] | 177 | const Digraph *G; |
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[244] | 178 | //Pointer to the map of predecessor arcs. |
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[100] | 179 | PredMap *_pred; |
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[244] | 180 | //Indicates if _pred is locally allocated (true) or not. |
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[100] | 181 | bool local_pred; |
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[244] | 182 | //Pointer to the map of distances. |
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[100] | 183 | DistMap *_dist; |
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[244] | 184 | //Indicates if _dist is locally allocated (true) or not. |
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[100] | 185 | bool local_dist; |
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[244] | 186 | //Pointer to the map of reached status of the nodes. |
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[100] | 187 | ReachedMap *_reached; |
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[244] | 188 | //Indicates if _reached is locally allocated (true) or not. |
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[100] | 189 | bool local_reached; |
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[244] | 190 | //Pointer to the map of processed status of the nodes. |
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[100] | 191 | ProcessedMap *_processed; |
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[244] | 192 | //Indicates if _processed is locally allocated (true) or not. |
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[100] | 193 | bool local_processed; |
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| 194 | |
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| 195 | std::vector<typename Digraph::Node> _queue; |
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| 196 | int _queue_head,_queue_tail,_queue_next_dist; |
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| 197 | int _curr_dist; |
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| 198 | |
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| 199 | ///Creates the maps if necessary. |
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| 200 | ///\todo Better memory allocation (instead of new). |
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[209] | 201 | void create_maps() |
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[100] | 202 | { |
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| 203 | if(!_pred) { |
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[209] | 204 | local_pred = true; |
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| 205 | _pred = Traits::createPredMap(*G); |
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[100] | 206 | } |
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| 207 | if(!_dist) { |
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[209] | 208 | local_dist = true; |
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| 209 | _dist = Traits::createDistMap(*G); |
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[100] | 210 | } |
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| 211 | if(!_reached) { |
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[209] | 212 | local_reached = true; |
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| 213 | _reached = Traits::createReachedMap(*G); |
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[100] | 214 | } |
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| 215 | if(!_processed) { |
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[209] | 216 | local_processed = true; |
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| 217 | _processed = Traits::createProcessedMap(*G); |
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[100] | 218 | } |
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| 219 | } |
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| 220 | |
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| 221 | protected: |
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[209] | 222 | |
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[100] | 223 | Bfs() {} |
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[209] | 224 | |
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[100] | 225 | public: |
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[209] | 226 | |
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[100] | 227 | typedef Bfs Create; |
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| 228 | |
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| 229 | ///\name Named template parameters |
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| 230 | |
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| 231 | ///@{ |
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| 232 | |
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| 233 | template <class T> |
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| 234 | struct DefPredMapTraits : public Traits { |
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| 235 | typedef T PredMap; |
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[209] | 236 | static PredMap *createPredMap(const Digraph &) |
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[100] | 237 | { |
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[209] | 238 | throw UninitializedParameter(); |
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[100] | 239 | } |
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| 240 | }; |
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| 241 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 242 | ///\ref PredMap type. |
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[100] | 243 | /// |
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[244] | 244 | ///\ref named-templ-param "Named parameter" for setting |
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| 245 | ///\ref PredMap type. |
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[100] | 246 | template <class T> |
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[209] | 247 | struct DefPredMap : public Bfs< Digraph, DefPredMapTraits<T> > { |
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[100] | 248 | typedef Bfs< Digraph, DefPredMapTraits<T> > Create; |
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| 249 | }; |
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[209] | 250 | |
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[100] | 251 | template <class T> |
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| 252 | struct DefDistMapTraits : public Traits { |
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| 253 | typedef T DistMap; |
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[209] | 254 | static DistMap *createDistMap(const Digraph &) |
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[100] | 255 | { |
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[209] | 256 | throw UninitializedParameter(); |
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[100] | 257 | } |
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| 258 | }; |
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| 259 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 260 | ///\ref DistMap type. |
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[100] | 261 | /// |
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[244] | 262 | ///\ref named-templ-param "Named parameter" for setting |
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| 263 | ///\ref DistMap type. |
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[100] | 264 | template <class T> |
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[209] | 265 | struct DefDistMap : public Bfs< Digraph, DefDistMapTraits<T> > { |
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[100] | 266 | typedef Bfs< Digraph, DefDistMapTraits<T> > Create; |
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| 267 | }; |
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[209] | 268 | |
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[100] | 269 | template <class T> |
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| 270 | struct DefReachedMapTraits : public Traits { |
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| 271 | typedef T ReachedMap; |
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[209] | 272 | static ReachedMap *createReachedMap(const Digraph &) |
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[100] | 273 | { |
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[209] | 274 | throw UninitializedParameter(); |
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[100] | 275 | } |
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| 276 | }; |
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| 277 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 278 | ///\ref ReachedMap type. |
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[100] | 279 | /// |
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[244] | 280 | ///\ref named-templ-param "Named parameter" for setting |
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| 281 | ///\ref ReachedMap type. |
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[100] | 282 | template <class T> |
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[209] | 283 | struct DefReachedMap : public Bfs< Digraph, DefReachedMapTraits<T> > { |
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[100] | 284 | typedef Bfs< Digraph, DefReachedMapTraits<T> > Create; |
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| 285 | }; |
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[209] | 286 | |
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[100] | 287 | template <class T> |
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| 288 | struct DefProcessedMapTraits : public Traits { |
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| 289 | typedef T ProcessedMap; |
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[209] | 290 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 291 | { |
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[209] | 292 | throw UninitializedParameter(); |
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[100] | 293 | } |
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| 294 | }; |
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| 295 | ///\brief \ref named-templ-param "Named parameter" for setting |
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[244] | 296 | ///\ref ProcessedMap type. |
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[100] | 297 | /// |
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[244] | 298 | ///\ref named-templ-param "Named parameter" for setting |
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| 299 | ///\ref ProcessedMap type. |
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[100] | 300 | template <class T> |
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| 301 | struct DefProcessedMap : public Bfs< Digraph, DefProcessedMapTraits<T> > { |
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| 302 | typedef Bfs< Digraph, DefProcessedMapTraits<T> > Create; |
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| 303 | }; |
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[209] | 304 | |
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[100] | 305 | struct DefDigraphProcessedMapTraits : public Traits { |
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| 306 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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[244] | 307 | static ProcessedMap *createProcessedMap(const Digraph &g) |
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[100] | 308 | { |
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[244] | 309 | return new ProcessedMap(g); |
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[100] | 310 | } |
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| 311 | }; |
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[244] | 312 | ///\brief \ref named-templ-param "Named parameter" for setting |
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| 313 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 314 | /// |
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[244] | 315 | ///\ref named-templ-param "Named parameter" for setting |
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| 316 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
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[100] | 317 | ///If you don't set it explicitly, it will be automatically allocated. |
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| 318 | template <class T> |
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| 319 | struct DefProcessedMapToBeDefaultMap : |
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[209] | 320 | public Bfs< Digraph, DefDigraphProcessedMapTraits> { |
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[100] | 321 | typedef Bfs< Digraph, DefDigraphProcessedMapTraits> Create; |
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| 322 | }; |
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[209] | 323 | |
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[100] | 324 | ///@} |
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| 325 | |
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[209] | 326 | public: |
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| 327 | |
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[100] | 328 | ///Constructor. |
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[209] | 329 | |
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[244] | 330 | ///Constructor. |
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| 331 | ///\param g The digraph the algorithm runs on. |
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| 332 | Bfs(const Digraph &g) : |
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| 333 | G(&g), |
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[100] | 334 | _pred(NULL), local_pred(false), |
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| 335 | _dist(NULL), local_dist(false), |
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| 336 | _reached(NULL), local_reached(false), |
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| 337 | _processed(NULL), local_processed(false) |
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| 338 | { } |
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[209] | 339 | |
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[100] | 340 | ///Destructor. |
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[209] | 341 | ~Bfs() |
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[100] | 342 | { |
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| 343 | if(local_pred) delete _pred; |
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| 344 | if(local_dist) delete _dist; |
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| 345 | if(local_reached) delete _reached; |
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| 346 | if(local_processed) delete _processed; |
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| 347 | } |
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| 348 | |
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[244] | 349 | ///Sets the map that stores the predecessor arcs. |
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[100] | 350 | |
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[244] | 351 | ///Sets the map that stores the predecessor arcs. |
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[100] | 352 | ///If you don't use this function before calling \ref run(), |
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| 353 | ///it will allocate one. The destructor deallocates this |
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| 354 | ///automatically allocated map, of course. |
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| 355 | ///\return <tt> (*this) </tt> |
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[209] | 356 | Bfs &predMap(PredMap &m) |
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[100] | 357 | { |
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| 358 | if(local_pred) { |
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[209] | 359 | delete _pred; |
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| 360 | local_pred=false; |
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[100] | 361 | } |
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| 362 | _pred = &m; |
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| 363 | return *this; |
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| 364 | } |
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| 365 | |
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[244] | 366 | ///Sets the map that indicates which nodes are reached. |
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[100] | 367 | |
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[244] | 368 | ///Sets the map that indicates which nodes are reached. |
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[100] | 369 | ///If you don't use this function before calling \ref run(), |
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| 370 | ///it will allocate one. The destructor deallocates this |
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| 371 | ///automatically allocated map, of course. |
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| 372 | ///\return <tt> (*this) </tt> |
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[209] | 373 | Bfs &reachedMap(ReachedMap &m) |
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[100] | 374 | { |
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| 375 | if(local_reached) { |
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[209] | 376 | delete _reached; |
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| 377 | local_reached=false; |
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[100] | 378 | } |
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| 379 | _reached = &m; |
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| 380 | return *this; |
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| 381 | } |
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| 382 | |
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[244] | 383 | ///Sets the map that indicates which nodes are processed. |
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[100] | 384 | |
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[244] | 385 | ///Sets the map that indicates which nodes are processed. |
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[100] | 386 | ///If you don't use this function before calling \ref run(), |
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| 387 | ///it will allocate one. The destructor deallocates this |
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| 388 | ///automatically allocated map, of course. |
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| 389 | ///\return <tt> (*this) </tt> |
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[209] | 390 | Bfs &processedMap(ProcessedMap &m) |
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[100] | 391 | { |
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| 392 | if(local_processed) { |
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[209] | 393 | delete _processed; |
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| 394 | local_processed=false; |
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[100] | 395 | } |
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| 396 | _processed = &m; |
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| 397 | return *this; |
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| 398 | } |
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| 399 | |
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[244] | 400 | ///Sets the map that stores the distances of the nodes. |
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[100] | 401 | |
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[244] | 402 | ///Sets the map that stores the distances of the nodes calculated by |
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| 403 | ///the algorithm. |
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[100] | 404 | ///If you don't use this function before calling \ref run(), |
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| 405 | ///it will allocate one. The destructor deallocates this |
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| 406 | ///automatically allocated map, of course. |
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| 407 | ///\return <tt> (*this) </tt> |
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[209] | 408 | Bfs &distMap(DistMap &m) |
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[100] | 409 | { |
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| 410 | if(local_dist) { |
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[209] | 411 | delete _dist; |
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| 412 | local_dist=false; |
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[100] | 413 | } |
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| 414 | _dist = &m; |
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| 415 | return *this; |
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| 416 | } |
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| 417 | |
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| 418 | public: |
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[244] | 419 | |
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[100] | 420 | ///\name Execution control |
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| 421 | ///The simplest way to execute the algorithm is to use |
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[244] | 422 | ///one of the member functions called \ref lemon::Bfs::run() "run()". |
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[100] | 423 | ///\n |
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[244] | 424 | ///If you need more control on the execution, first you must call |
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| 425 | ///\ref lemon::Bfs::init() "init()", then you can add several source |
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| 426 | ///nodes with \ref lemon::Bfs::addSource() "addSource()". |
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| 427 | ///Finally \ref lemon::Bfs::start() "start()" will perform the |
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| 428 | ///actual path computation. |
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[100] | 429 | |
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| 430 | ///@{ |
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| 431 | |
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[244] | 432 | ///Initializes the internal data structures. |
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| 433 | |
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[100] | 434 | ///Initializes the internal data structures. |
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| 435 | /// |
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| 436 | void init() |
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| 437 | { |
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| 438 | create_maps(); |
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| 439 | _queue.resize(countNodes(*G)); |
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| 440 | _queue_head=_queue_tail=0; |
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| 441 | _curr_dist=1; |
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| 442 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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[209] | 443 | _pred->set(u,INVALID); |
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| 444 | _reached->set(u,false); |
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| 445 | _processed->set(u,false); |
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[100] | 446 | } |
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| 447 | } |
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[209] | 448 | |
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[100] | 449 | ///Adds a new source node. |
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| 450 | |
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| 451 | ///Adds a new source node to the set of nodes to be processed. |
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| 452 | /// |
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| 453 | void addSource(Node s) |
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| 454 | { |
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| 455 | if(!(*_reached)[s]) |
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[209] | 456 | { |
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| 457 | _reached->set(s,true); |
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| 458 | _pred->set(s,INVALID); |
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| 459 | _dist->set(s,0); |
---|
| 460 | _queue[_queue_head++]=s; |
---|
| 461 | _queue_next_dist=_queue_head; |
---|
| 462 | } |
---|
[100] | 463 | } |
---|
[209] | 464 | |
---|
[100] | 465 | ///Processes the next node. |
---|
| 466 | |
---|
| 467 | ///Processes the next node. |
---|
| 468 | /// |
---|
| 469 | ///\return The processed node. |
---|
| 470 | /// |
---|
[244] | 471 | ///\pre The queue must not be empty. |
---|
[100] | 472 | Node processNextNode() |
---|
| 473 | { |
---|
| 474 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 475 | _curr_dist++; |
---|
| 476 | _queue_next_dist=_queue_head; |
---|
[100] | 477 | } |
---|
| 478 | Node n=_queue[_queue_tail++]; |
---|
| 479 | _processed->set(n,true); |
---|
| 480 | Node m; |
---|
| 481 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 482 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 483 | _queue[_queue_head++]=m; |
---|
| 484 | _reached->set(m,true); |
---|
| 485 | _pred->set(m,e); |
---|
| 486 | _dist->set(m,_curr_dist); |
---|
| 487 | } |
---|
[100] | 488 | return n; |
---|
| 489 | } |
---|
| 490 | |
---|
| 491 | ///Processes the next node. |
---|
| 492 | |
---|
[244] | 493 | ///Processes the next node and checks if the given target node |
---|
[100] | 494 | ///is reached. If the target node is reachable from the processed |
---|
[244] | 495 | ///node, then the \c reach parameter will be set to \c true. |
---|
[100] | 496 | /// |
---|
| 497 | ///\param target The target node. |
---|
[244] | 498 | ///\retval reach Indicates if the target node is reached. |
---|
| 499 | ///It should be initially \c false. |
---|
| 500 | /// |
---|
[100] | 501 | ///\return The processed node. |
---|
| 502 | /// |
---|
[244] | 503 | ///\pre The queue must not be empty. |
---|
[100] | 504 | Node processNextNode(Node target, bool& reach) |
---|
| 505 | { |
---|
| 506 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 507 | _curr_dist++; |
---|
| 508 | _queue_next_dist=_queue_head; |
---|
[100] | 509 | } |
---|
| 510 | Node n=_queue[_queue_tail++]; |
---|
| 511 | _processed->set(n,true); |
---|
| 512 | Node m; |
---|
| 513 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 514 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 515 | _queue[_queue_head++]=m; |
---|
| 516 | _reached->set(m,true); |
---|
| 517 | _pred->set(m,e); |
---|
| 518 | _dist->set(m,_curr_dist); |
---|
[100] | 519 | reach = reach || (target == m); |
---|
[209] | 520 | } |
---|
[100] | 521 | return n; |
---|
| 522 | } |
---|
| 523 | |
---|
| 524 | ///Processes the next node. |
---|
| 525 | |
---|
[244] | 526 | ///Processes the next node and checks if at least one of reached |
---|
| 527 | ///nodes has \c true value in the \c nm node map. If one node |
---|
| 528 | ///with \c true value is reachable from the processed node, then the |
---|
| 529 | ///\c rnode parameter will be set to the first of such nodes. |
---|
[100] | 530 | /// |
---|
[244] | 531 | ///\param nm A \c bool (or convertible) node map that indicates the |
---|
| 532 | ///possible targets. |
---|
[100] | 533 | ///\retval rnode The reached target node. |
---|
[244] | 534 | ///It should be initially \c INVALID. |
---|
| 535 | /// |
---|
[100] | 536 | ///\return The processed node. |
---|
| 537 | /// |
---|
[244] | 538 | ///\pre The queue must not be empty. |
---|
[100] | 539 | template<class NM> |
---|
| 540 | Node processNextNode(const NM& nm, Node& rnode) |
---|
| 541 | { |
---|
| 542 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 543 | _curr_dist++; |
---|
| 544 | _queue_next_dist=_queue_head; |
---|
[100] | 545 | } |
---|
| 546 | Node n=_queue[_queue_tail++]; |
---|
| 547 | _processed->set(n,true); |
---|
| 548 | Node m; |
---|
| 549 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 550 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 551 | _queue[_queue_head++]=m; |
---|
| 552 | _reached->set(m,true); |
---|
| 553 | _pred->set(m,e); |
---|
| 554 | _dist->set(m,_curr_dist); |
---|
| 555 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 556 | } |
---|
[100] | 557 | return n; |
---|
| 558 | } |
---|
[209] | 559 | |
---|
[244] | 560 | ///The next node to be processed. |
---|
[100] | 561 | |
---|
[244] | 562 | ///Returns the next node to be processed or \c INVALID if the queue |
---|
| 563 | ///is empty. |
---|
| 564 | Node nextNode() const |
---|
[209] | 565 | { |
---|
[100] | 566 | return _queue_tail<_queue_head?_queue[_queue_tail]:INVALID; |
---|
| 567 | } |
---|
[209] | 568 | |
---|
[100] | 569 | ///\brief Returns \c false if there are nodes |
---|
[244] | 570 | ///to be processed. |
---|
[100] | 571 | /// |
---|
| 572 | ///Returns \c false if there are nodes |
---|
[244] | 573 | ///to be processed in the queue. |
---|
| 574 | bool emptyQueue() const { return _queue_tail==_queue_head; } |
---|
| 575 | |
---|
[100] | 576 | ///Returns the number of the nodes to be processed. |
---|
[209] | 577 | |
---|
[100] | 578 | ///Returns the number of the nodes to be processed in the queue. |
---|
[244] | 579 | int queueSize() const { return _queue_head-_queue_tail; } |
---|
[209] | 580 | |
---|
[100] | 581 | ///Executes the algorithm. |
---|
| 582 | |
---|
| 583 | ///Executes the algorithm. |
---|
| 584 | /// |
---|
[244] | 585 | ///This method runs the %BFS algorithm from the root node(s) |
---|
| 586 | ///in order to compute the shortest path to each node. |
---|
[100] | 587 | /// |
---|
[244] | 588 | ///The algorithm computes |
---|
| 589 | ///- the shortest path tree (forest), |
---|
| 590 | ///- the distance of each node from the root(s). |
---|
| 591 | /// |
---|
| 592 | ///\pre init() must be called and at least one root node should be |
---|
| 593 | ///added with addSource() before using this function. |
---|
| 594 | /// |
---|
| 595 | ///\note <tt>b.start()</tt> is just a shortcut of the following code. |
---|
| 596 | ///\code |
---|
| 597 | /// while ( !b.emptyQueue() ) { |
---|
| 598 | /// b.processNextNode(); |
---|
| 599 | /// } |
---|
| 600 | ///\endcode |
---|
[100] | 601 | void start() |
---|
| 602 | { |
---|
| 603 | while ( !emptyQueue() ) processNextNode(); |
---|
| 604 | } |
---|
[209] | 605 | |
---|
[244] | 606 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 607 | |
---|
[244] | 608 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 609 | /// |
---|
| 610 | ///This method runs the %BFS algorithm from the root node(s) |
---|
| 611 | ///in order to compute the shortest path to \c dest. |
---|
[244] | 612 | /// |
---|
[100] | 613 | ///The algorithm computes |
---|
[244] | 614 | ///- the shortest path to \c dest, |
---|
| 615 | ///- the distance of \c dest from the root(s). |
---|
| 616 | /// |
---|
| 617 | ///\pre init() must be called and at least one root node should be |
---|
| 618 | ///added with addSource() before using this function. |
---|
| 619 | /// |
---|
| 620 | ///\note <tt>b.start(t)</tt> is just a shortcut of the following code. |
---|
| 621 | ///\code |
---|
| 622 | /// bool reach = false; |
---|
| 623 | /// while ( !b.emptyQueue() && !reach ) { |
---|
| 624 | /// b.processNextNode(t, reach); |
---|
| 625 | /// } |
---|
| 626 | ///\endcode |
---|
[100] | 627 | void start(Node dest) |
---|
| 628 | { |
---|
| 629 | bool reach = false; |
---|
| 630 | while ( !emptyQueue() && !reach ) processNextNode(dest, reach); |
---|
| 631 | } |
---|
[209] | 632 | |
---|
[100] | 633 | ///Executes the algorithm until a condition is met. |
---|
| 634 | |
---|
| 635 | ///Executes the algorithm until a condition is met. |
---|
| 636 | /// |
---|
[244] | 637 | ///This method runs the %BFS algorithm from the root node(s) in |
---|
| 638 | ///order to compute the shortest path to a node \c v with |
---|
| 639 | /// <tt>nm[v]</tt> true, if such a node can be found. |
---|
[100] | 640 | /// |
---|
[244] | 641 | ///\param nm A \c bool (or convertible) node map. The algorithm |
---|
| 642 | ///will stop when it reaches a node \c v with <tt>nm[v]</tt> true. |
---|
[100] | 643 | /// |
---|
| 644 | ///\return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 645 | ///\c INVALID if no such node was found. |
---|
[244] | 646 | /// |
---|
| 647 | ///\pre init() must be called and at least one root node should be |
---|
| 648 | ///added with addSource() before using this function. |
---|
| 649 | /// |
---|
| 650 | ///\note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
---|
| 651 | ///\code |
---|
| 652 | /// Node rnode = INVALID; |
---|
| 653 | /// while ( !b.emptyQueue() && rnode == INVALID ) { |
---|
| 654 | /// b.processNextNode(nm, rnode); |
---|
| 655 | /// } |
---|
| 656 | /// return rnode; |
---|
| 657 | ///\endcode |
---|
| 658 | template<class NodeBoolMap> |
---|
| 659 | Node start(const NodeBoolMap &nm) |
---|
[100] | 660 | { |
---|
| 661 | Node rnode = INVALID; |
---|
| 662 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 663 | processNextNode(nm, rnode); |
---|
[100] | 664 | } |
---|
| 665 | return rnode; |
---|
| 666 | } |
---|
[209] | 667 | |
---|
[244] | 668 | ///Runs the algorithm from the given node. |
---|
[209] | 669 | |
---|
[244] | 670 | ///This method runs the %BFS algorithm from node \c s |
---|
| 671 | ///in order to compute the shortest path to each node. |
---|
[100] | 672 | /// |
---|
[244] | 673 | ///The algorithm computes |
---|
| 674 | ///- the shortest path tree, |
---|
| 675 | ///- the distance of each node from the root. |
---|
| 676 | /// |
---|
| 677 | ///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 678 | ///\code |
---|
| 679 | /// b.init(); |
---|
| 680 | /// b.addSource(s); |
---|
| 681 | /// b.start(); |
---|
| 682 | ///\endcode |
---|
| 683 | void run(Node s) { |
---|
| 684 | init(); |
---|
| 685 | addSource(s); |
---|
| 686 | start(); |
---|
| 687 | } |
---|
[209] | 688 | |
---|
[100] | 689 | ///Finds the shortest path between \c s and \c t. |
---|
[209] | 690 | |
---|
[244] | 691 | ///This method runs the %BFS algorithm from node \c s |
---|
| 692 | ///in order to compute the shortest path to \c t. |
---|
[100] | 693 | /// |
---|
[244] | 694 | ///\return The length of the shortest <tt>s</tt>--<tt>t</tt> path, |
---|
| 695 | ///if \c t is reachable form \c s, \c 0 otherwise. |
---|
| 696 | /// |
---|
| 697 | ///\note Apart from the return value, <tt>b.run(s,t)</tt> is just a |
---|
| 698 | ///shortcut of the following code. |
---|
[100] | 699 | ///\code |
---|
| 700 | /// b.init(); |
---|
| 701 | /// b.addSource(s); |
---|
| 702 | /// b.start(t); |
---|
| 703 | ///\endcode |
---|
| 704 | int run(Node s,Node t) { |
---|
| 705 | init(); |
---|
| 706 | addSource(s); |
---|
| 707 | start(t); |
---|
| 708 | return reached(t) ? _curr_dist : 0; |
---|
| 709 | } |
---|
[209] | 710 | |
---|
[244] | 711 | ///Runs the algorithm to visit all nodes in the digraph. |
---|
| 712 | |
---|
| 713 | ///This method runs the %BFS algorithm in order to |
---|
| 714 | ///compute the shortest path to each node. |
---|
| 715 | /// |
---|
| 716 | ///The algorithm computes |
---|
| 717 | ///- the shortest path tree (forest), |
---|
| 718 | ///- the distance of each node from the root(s). |
---|
| 719 | /// |
---|
| 720 | ///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
| 721 | ///\code |
---|
| 722 | /// b.init(); |
---|
| 723 | /// for (NodeIt n(gr); n != INVALID; ++n) { |
---|
| 724 | /// if (!b.reached(n)) { |
---|
| 725 | /// b.addSource(n); |
---|
| 726 | /// b.start(); |
---|
| 727 | /// } |
---|
| 728 | /// } |
---|
| 729 | ///\endcode |
---|
| 730 | void run() { |
---|
| 731 | init(); |
---|
| 732 | for (NodeIt n(*G); n != INVALID; ++n) { |
---|
| 733 | if (!reached(n)) { |
---|
| 734 | addSource(n); |
---|
| 735 | start(); |
---|
| 736 | } |
---|
| 737 | } |
---|
| 738 | } |
---|
| 739 | |
---|
[100] | 740 | ///@} |
---|
| 741 | |
---|
| 742 | ///\name Query Functions |
---|
| 743 | ///The result of the %BFS algorithm can be obtained using these |
---|
| 744 | ///functions.\n |
---|
[244] | 745 | ///Either \ref lemon::Bfs::run() "run()" or \ref lemon::Bfs::start() |
---|
| 746 | ///"start()" must be called before using them. |
---|
[209] | 747 | |
---|
[100] | 748 | ///@{ |
---|
| 749 | |
---|
[244] | 750 | ///The shortest path to a node. |
---|
[100] | 751 | |
---|
[244] | 752 | ///Returns the shortest path to a node. |
---|
| 753 | /// |
---|
| 754 | ///\warning \c t should be reachable from the root(s). |
---|
| 755 | /// |
---|
| 756 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 757 | ///using this function. |
---|
| 758 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
[100] | 759 | |
---|
| 760 | ///The distance of a node from the root(s). |
---|
| 761 | |
---|
| 762 | ///Returns the distance of a node from the root(s). |
---|
[244] | 763 | /// |
---|
| 764 | ///\warning If node \c v is not reachable from the root(s), then |
---|
| 765 | ///the return value of this function is undefined. |
---|
| 766 | /// |
---|
| 767 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 768 | ///using this function. |
---|
[100] | 769 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 770 | |
---|
[244] | 771 | ///Returns the 'previous arc' of the shortest path tree for a node. |
---|
[100] | 772 | |
---|
[244] | 773 | ///This function returns the 'previous arc' of the shortest path |
---|
| 774 | ///tree for the node \c v, i.e. it returns the last arc of a |
---|
| 775 | ///shortest path from the root(s) to \c v. It is \c INVALID if \c v |
---|
| 776 | ///is not reachable from the root(s) or if \c v is a root. |
---|
| 777 | /// |
---|
| 778 | ///The shortest path tree used here is equal to the shortest path |
---|
| 779 | ///tree used in \ref predNode(). |
---|
| 780 | /// |
---|
| 781 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 782 | ///using this function. |
---|
[100] | 783 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 784 | |
---|
[244] | 785 | ///Returns the 'previous node' of the shortest path tree for a node. |
---|
[100] | 786 | |
---|
[244] | 787 | ///This function returns the 'previous node' of the shortest path |
---|
| 788 | ///tree for the node \c v, i.e. it returns the last but one node |
---|
| 789 | ///from a shortest path from the root(s) to \c v. It is \c INVALID |
---|
| 790 | ///if \c v is not reachable from the root(s) or if \c v is a root. |
---|
| 791 | /// |
---|
[100] | 792 | ///The shortest path tree used here is equal to the shortest path |
---|
| 793 | ///tree used in \ref predArc(). |
---|
[244] | 794 | /// |
---|
[100] | 795 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 796 | ///using this function. |
---|
| 797 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
[209] | 798 | G->source((*_pred)[v]); } |
---|
| 799 | |
---|
[244] | 800 | ///\brief Returns a const reference to the node map that stores the |
---|
| 801 | /// distances of the nodes. |
---|
| 802 | /// |
---|
| 803 | ///Returns a const reference to the node map that stores the distances |
---|
| 804 | ///of the nodes calculated by the algorithm. |
---|
| 805 | /// |
---|
| 806 | ///\pre Either \ref run() or \ref init() |
---|
| 807 | ///must be called before using this function. |
---|
[100] | 808 | const DistMap &distMap() const { return *_dist;} |
---|
[209] | 809 | |
---|
[244] | 810 | ///\brief Returns a const reference to the node map that stores the |
---|
| 811 | ///predecessor arcs. |
---|
| 812 | /// |
---|
| 813 | ///Returns a const reference to the node map that stores the predecessor |
---|
| 814 | ///arcs, which form the shortest path tree. |
---|
| 815 | /// |
---|
[100] | 816 | ///\pre Either \ref run() or \ref init() |
---|
| 817 | ///must be called before using this function. |
---|
| 818 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 819 | |
---|
[244] | 820 | ///Checks if a node is reachable from the root(s). |
---|
[100] | 821 | |
---|
[244] | 822 | ///Returns \c true if \c v is reachable from the root(s). |
---|
[100] | 823 | ///\pre Either \ref run() or \ref start() |
---|
| 824 | ///must be called before using this function. |
---|
[244] | 825 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[209] | 826 | |
---|
[100] | 827 | ///@} |
---|
| 828 | }; |
---|
| 829 | |
---|
[244] | 830 | ///Default traits class of bfs() function. |
---|
[100] | 831 | |
---|
[244] | 832 | ///Default traits class of bfs() function. |
---|
[157] | 833 | ///\tparam GR Digraph type. |
---|
[100] | 834 | template<class GR> |
---|
| 835 | struct BfsWizardDefaultTraits |
---|
| 836 | { |
---|
[244] | 837 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 838 | typedef GR Digraph; |
---|
[244] | 839 | |
---|
| 840 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 841 | ///arcs of the shortest paths. |
---|
[209] | 842 | /// |
---|
[244] | 843 | ///The type of the map that stores the predecessor |
---|
[100] | 844 | ///arcs of the shortest paths. |
---|
| 845 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[244] | 846 | typedef NullMap<typename Digraph::Node,typename Digraph::Arc> PredMap; |
---|
| 847 | ///Instantiates a \ref PredMap. |
---|
[209] | 848 | |
---|
| 849 | ///This function instantiates a \ref PredMap. |
---|
[244] | 850 | ///\param g is the digraph, to which we would like to define the |
---|
| 851 | ///\ref PredMap. |
---|
[100] | 852 | ///\todo The digraph alone may be insufficient to initialize |
---|
| 853 | #ifdef DOXYGEN |
---|
[244] | 854 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 855 | #else |
---|
[244] | 856 | static PredMap *createPredMap(const Digraph &) |
---|
[100] | 857 | #endif |
---|
| 858 | { |
---|
| 859 | return new PredMap(); |
---|
| 860 | } |
---|
| 861 | |
---|
| 862 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 863 | |
---|
[100] | 864 | ///The type of the map that indicates which nodes are processed. |
---|
| 865 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 866 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[244] | 867 | ///Instantiates a \ref ProcessedMap. |
---|
[209] | 868 | |
---|
| 869 | ///This function instantiates a \ref ProcessedMap. |
---|
[100] | 870 | ///\param g is the digraph, to which |
---|
[244] | 871 | ///we would like to define the \ref ProcessedMap. |
---|
[100] | 872 | #ifdef DOXYGEN |
---|
[244] | 873 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 874 | #else |
---|
[244] | 875 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 876 | #endif |
---|
| 877 | { |
---|
| 878 | return new ProcessedMap(); |
---|
| 879 | } |
---|
[244] | 880 | |
---|
[100] | 881 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 882 | |
---|
[100] | 883 | ///The type of the map that indicates which nodes are reached. |
---|
[244] | 884 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 885 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[244] | 886 | ///Instantiates a \ref ReachedMap. |
---|
[209] | 887 | |
---|
| 888 | ///This function instantiates a \ref ReachedMap. |
---|
[244] | 889 | ///\param g is the digraph, to which |
---|
[100] | 890 | ///we would like to define the \ref ReachedMap. |
---|
[244] | 891 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 892 | { |
---|
[244] | 893 | return new ReachedMap(g); |
---|
[100] | 894 | } |
---|
[209] | 895 | |
---|
[244] | 896 | ///The type of the map that stores the distances of the nodes. |
---|
| 897 | |
---|
| 898 | ///The type of the map that stores the distances of the nodes. |
---|
[100] | 899 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 900 | /// |
---|
| 901 | typedef NullMap<typename Digraph::Node,int> DistMap; |
---|
[244] | 902 | ///Instantiates a \ref DistMap. |
---|
[209] | 903 | |
---|
| 904 | ///This function instantiates a \ref DistMap. |
---|
[210] | 905 | ///\param g is the digraph, to which we would like to define |
---|
| 906 | ///the \ref DistMap |
---|
[100] | 907 | #ifdef DOXYGEN |
---|
[244] | 908 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 909 | #else |
---|
[244] | 910 | static DistMap *createDistMap(const Digraph &) |
---|
[100] | 911 | #endif |
---|
| 912 | { |
---|
| 913 | return new DistMap(); |
---|
| 914 | } |
---|
| 915 | }; |
---|
[209] | 916 | |
---|
[244] | 917 | /// Default traits class used by \ref BfsWizard |
---|
[100] | 918 | |
---|
| 919 | /// To make it easier to use Bfs algorithm |
---|
[244] | 920 | /// we have created a wizard class. |
---|
[100] | 921 | /// This \ref BfsWizard class needs default traits, |
---|
[244] | 922 | /// as well as the \ref Bfs class. |
---|
[100] | 923 | /// The \ref BfsWizardBase is a class to be the default traits of the |
---|
| 924 | /// \ref BfsWizard class. |
---|
| 925 | template<class GR> |
---|
| 926 | class BfsWizardBase : public BfsWizardDefaultTraits<GR> |
---|
| 927 | { |
---|
| 928 | |
---|
| 929 | typedef BfsWizardDefaultTraits<GR> Base; |
---|
| 930 | protected: |
---|
[244] | 931 | //The type of the nodes in the digraph. |
---|
[100] | 932 | typedef typename Base::Digraph::Node Node; |
---|
| 933 | |
---|
[244] | 934 | //Pointer to the digraph the algorithm runs on. |
---|
[100] | 935 | void *_g; |
---|
[244] | 936 | //Pointer to the map of reached nodes. |
---|
[100] | 937 | void *_reached; |
---|
[244] | 938 | //Pointer to the map of processed nodes. |
---|
[100] | 939 | void *_processed; |
---|
[244] | 940 | //Pointer to the map of predecessors arcs. |
---|
[100] | 941 | void *_pred; |
---|
[244] | 942 | //Pointer to the map of distances. |
---|
[100] | 943 | void *_dist; |
---|
[244] | 944 | //Pointer to the source node. |
---|
[100] | 945 | Node _source; |
---|
[209] | 946 | |
---|
[100] | 947 | public: |
---|
| 948 | /// Constructor. |
---|
[209] | 949 | |
---|
[100] | 950 | /// This constructor does not require parameters, therefore it initiates |
---|
| 951 | /// all of the attributes to default values (0, INVALID). |
---|
| 952 | BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[244] | 953 | _dist(0), _source(INVALID) {} |
---|
[100] | 954 | |
---|
| 955 | /// Constructor. |
---|
[209] | 956 | |
---|
[100] | 957 | /// This constructor requires some parameters, |
---|
| 958 | /// listed in the parameters list. |
---|
| 959 | /// Others are initiated to 0. |
---|
[244] | 960 | /// \param g The digraph the algorithm runs on. |
---|
| 961 | /// \param s The source node. |
---|
[100] | 962 | BfsWizardBase(const GR &g, Node s=INVALID) : |
---|
[209] | 963 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
---|
[100] | 964 | _reached(0), _processed(0), _pred(0), _dist(0), _source(s) {} |
---|
| 965 | |
---|
| 966 | }; |
---|
[209] | 967 | |
---|
[244] | 968 | /// Auxiliary class for the function type interface of BFS algorithm. |
---|
[100] | 969 | |
---|
[244] | 970 | /// This auxiliary class is created to implement the function type |
---|
| 971 | /// interface of \ref Bfs algorithm. It uses the functions and features |
---|
| 972 | /// of the plain \ref Bfs, but it is much simpler to use it. |
---|
| 973 | /// It should only be used through the \ref bfs() function, which makes |
---|
| 974 | /// it easier to use the algorithm. |
---|
[100] | 975 | /// |
---|
| 976 | /// Simplicity means that the way to change the types defined |
---|
| 977 | /// in the traits class is based on functions that returns the new class |
---|
| 978 | /// and not on templatable built-in classes. |
---|
| 979 | /// When using the plain \ref Bfs |
---|
| 980 | /// the new class with the modified type comes from |
---|
| 981 | /// the original class by using the :: |
---|
| 982 | /// operator. In the case of \ref BfsWizard only |
---|
[244] | 983 | /// a function have to be called, and it will |
---|
[100] | 984 | /// return the needed class. |
---|
| 985 | /// |
---|
[244] | 986 | /// It does not have own \ref run() method. When its \ref run() method |
---|
| 987 | /// is called, it initiates a plain \ref Bfs object, and calls the |
---|
| 988 | /// \ref Bfs::run() method of it. |
---|
[100] | 989 | template<class TR> |
---|
| 990 | class BfsWizard : public TR |
---|
| 991 | { |
---|
| 992 | typedef TR Base; |
---|
| 993 | |
---|
[244] | 994 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 995 | typedef typename TR::Digraph Digraph; |
---|
[244] | 996 | |
---|
[100] | 997 | typedef typename Digraph::Node Node; |
---|
| 998 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 999 | typedef typename Digraph::Arc Arc; |
---|
| 1000 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
[209] | 1001 | |
---|
[244] | 1002 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 1003 | ///arcs of the shortest paths. |
---|
| 1004 | typedef typename TR::PredMap PredMap; |
---|
[244] | 1005 | ///\brief The type of the map that stores the distances of the nodes. |
---|
[100] | 1006 | typedef typename TR::DistMap DistMap; |
---|
[244] | 1007 | ///\brief The type of the map that indicates which nodes are reached. |
---|
| 1008 | typedef typename TR::ReachedMap ReachedMap; |
---|
| 1009 | ///\brief The type of the map that indicates which nodes are processed. |
---|
| 1010 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
[100] | 1011 | |
---|
| 1012 | public: |
---|
[244] | 1013 | |
---|
[100] | 1014 | /// Constructor. |
---|
| 1015 | BfsWizard() : TR() {} |
---|
| 1016 | |
---|
| 1017 | /// Constructor that requires parameters. |
---|
| 1018 | |
---|
| 1019 | /// Constructor that requires parameters. |
---|
| 1020 | /// These parameters will be the default values for the traits class. |
---|
| 1021 | BfsWizard(const Digraph &g, Node s=INVALID) : |
---|
| 1022 | TR(g,s) {} |
---|
| 1023 | |
---|
| 1024 | ///Copy constructor |
---|
| 1025 | BfsWizard(const TR &b) : TR(b) {} |
---|
| 1026 | |
---|
| 1027 | ~BfsWizard() {} |
---|
| 1028 | |
---|
[244] | 1029 | ///Runs BFS algorithm from a source node. |
---|
[209] | 1030 | |
---|
[244] | 1031 | ///Runs BFS algorithm from a source node. |
---|
| 1032 | ///The node can be given with the \ref source() function. |
---|
[100] | 1033 | void run() |
---|
| 1034 | { |
---|
| 1035 | if(Base::_source==INVALID) throw UninitializedParameter(); |
---|
| 1036 | Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 1037 | if(Base::_reached) |
---|
[209] | 1038 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 1039 | if(Base::_processed) |
---|
[100] | 1040 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
[209] | 1041 | if(Base::_pred) |
---|
[100] | 1042 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
[209] | 1043 | if(Base::_dist) |
---|
[100] | 1044 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 1045 | alg.run(Base::_source); |
---|
| 1046 | } |
---|
| 1047 | |
---|
[244] | 1048 | ///Runs BFS algorithm from the given node. |
---|
[100] | 1049 | |
---|
[244] | 1050 | ///Runs BFS algorithm from the given node. |
---|
[100] | 1051 | ///\param s is the given source. |
---|
| 1052 | void run(Node s) |
---|
| 1053 | { |
---|
| 1054 | Base::_source=s; |
---|
| 1055 | run(); |
---|
| 1056 | } |
---|
| 1057 | |
---|
| 1058 | /// Sets the source node, from which the Bfs algorithm runs. |
---|
| 1059 | |
---|
| 1060 | /// Sets the source node, from which the Bfs algorithm runs. |
---|
| 1061 | /// \param s is the source node. |
---|
[209] | 1062 | BfsWizard<TR> &source(Node s) |
---|
[100] | 1063 | { |
---|
| 1064 | Base::_source=s; |
---|
| 1065 | return *this; |
---|
| 1066 | } |
---|
[209] | 1067 | |
---|
[244] | 1068 | template<class T> |
---|
| 1069 | struct DefPredMapBase : public Base { |
---|
| 1070 | typedef T PredMap; |
---|
| 1071 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
| 1072 | DefPredMapBase(const TR &b) : TR(b) {} |
---|
| 1073 | }; |
---|
| 1074 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1075 | ///for setting \ref PredMap object. |
---|
| 1076 | /// |
---|
| 1077 | /// \ref named-templ-param "Named parameter" |
---|
| 1078 | ///for setting \ref PredMap object. |
---|
| 1079 | template<class T> |
---|
| 1080 | BfsWizard<DefPredMapBase<T> > predMap(const T &t) |
---|
| 1081 | { |
---|
| 1082 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1083 | return BfsWizard<DefPredMapBase<T> >(*this); |
---|
| 1084 | } |
---|
| 1085 | |
---|
| 1086 | template<class T> |
---|
| 1087 | struct DefReachedMapBase : public Base { |
---|
| 1088 | typedef T ReachedMap; |
---|
| 1089 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
| 1090 | DefReachedMapBase(const TR &b) : TR(b) {} |
---|
| 1091 | }; |
---|
| 1092 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1093 | ///for setting \ref ReachedMap object. |
---|
| 1094 | /// |
---|
| 1095 | /// \ref named-templ-param "Named parameter" |
---|
| 1096 | ///for setting \ref ReachedMap object. |
---|
| 1097 | template<class T> |
---|
| 1098 | BfsWizard<DefReachedMapBase<T> > reachedMap(const T &t) |
---|
| 1099 | { |
---|
| 1100 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1101 | return BfsWizard<DefReachedMapBase<T> >(*this); |
---|
| 1102 | } |
---|
| 1103 | |
---|
| 1104 | template<class T> |
---|
| 1105 | struct DefProcessedMapBase : public Base { |
---|
| 1106 | typedef T ProcessedMap; |
---|
| 1107 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
| 1108 | DefProcessedMapBase(const TR &b) : TR(b) {} |
---|
| 1109 | }; |
---|
| 1110 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1111 | ///for setting \ref ProcessedMap object. |
---|
| 1112 | /// |
---|
| 1113 | /// \ref named-templ-param "Named parameter" |
---|
| 1114 | ///for setting \ref ProcessedMap object. |
---|
| 1115 | template<class T> |
---|
| 1116 | BfsWizard<DefProcessedMapBase<T> > processedMap(const T &t) |
---|
| 1117 | { |
---|
| 1118 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1119 | return BfsWizard<DefProcessedMapBase<T> >(*this); |
---|
| 1120 | } |
---|
| 1121 | |
---|
| 1122 | template<class T> |
---|
| 1123 | struct DefDistMapBase : public Base { |
---|
| 1124 | typedef T DistMap; |
---|
| 1125 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
| 1126 | DefDistMapBase(const TR &b) : TR(b) {} |
---|
| 1127 | }; |
---|
| 1128 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1129 | ///for setting \ref DistMap object. |
---|
| 1130 | /// |
---|
| 1131 | /// \ref named-templ-param "Named parameter" |
---|
| 1132 | ///for setting \ref DistMap object. |
---|
| 1133 | template<class T> |
---|
| 1134 | BfsWizard<DefDistMapBase<T> > distMap(const T &t) |
---|
| 1135 | { |
---|
| 1136 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1137 | return BfsWizard<DefDistMapBase<T> >(*this); |
---|
| 1138 | } |
---|
| 1139 | |
---|
[100] | 1140 | }; |
---|
[209] | 1141 | |
---|
[100] | 1142 | ///Function type interface for Bfs algorithm. |
---|
| 1143 | |
---|
| 1144 | /// \ingroup search |
---|
| 1145 | ///Function type interface for Bfs algorithm. |
---|
| 1146 | /// |
---|
| 1147 | ///This function also has several |
---|
| 1148 | ///\ref named-templ-func-param "named parameters", |
---|
| 1149 | ///they are declared as the members of class \ref BfsWizard. |
---|
| 1150 | ///The following |
---|
| 1151 | ///example shows how to use these parameters. |
---|
| 1152 | ///\code |
---|
| 1153 | /// bfs(g,source).predMap(preds).run(); |
---|
| 1154 | ///\endcode |
---|
| 1155 | ///\warning Don't forget to put the \ref BfsWizard::run() "run()" |
---|
| 1156 | ///to the end of the parameter list. |
---|
| 1157 | ///\sa BfsWizard |
---|
| 1158 | ///\sa Bfs |
---|
| 1159 | template<class GR> |
---|
| 1160 | BfsWizard<BfsWizardBase<GR> > |
---|
| 1161 | bfs(const GR &g,typename GR::Node s=INVALID) |
---|
| 1162 | { |
---|
| 1163 | return BfsWizard<BfsWizardBase<GR> >(g,s); |
---|
| 1164 | } |
---|
| 1165 | |
---|
| 1166 | #ifdef DOXYGEN |
---|
[244] | 1167 | /// \brief Visitor class for BFS. |
---|
[209] | 1168 | /// |
---|
[100] | 1169 | /// This class defines the interface of the BfsVisit events, and |
---|
[244] | 1170 | /// it could be the base of a real visitor class. |
---|
[100] | 1171 | template <typename _Digraph> |
---|
| 1172 | struct BfsVisitor { |
---|
| 1173 | typedef _Digraph Digraph; |
---|
| 1174 | typedef typename Digraph::Arc Arc; |
---|
| 1175 | typedef typename Digraph::Node Node; |
---|
[244] | 1176 | /// \brief Called for the source node(s) of the BFS. |
---|
[209] | 1177 | /// |
---|
[244] | 1178 | /// This function is called for the source node(s) of the BFS. |
---|
| 1179 | void start(const Node& node) {} |
---|
| 1180 | /// \brief Called when a node is reached first time. |
---|
| 1181 | /// |
---|
| 1182 | /// This function is called when a node is reached first time. |
---|
| 1183 | void reach(const Node& node) {} |
---|
| 1184 | /// \brief Called when a node is processed. |
---|
| 1185 | /// |
---|
| 1186 | /// This function is called when a node is processed. |
---|
| 1187 | void process(const Node& node) {} |
---|
| 1188 | /// \brief Called when an arc reaches a new node. |
---|
| 1189 | /// |
---|
| 1190 | /// This function is called when the BFS finds an arc whose target node |
---|
| 1191 | /// is not reached yet. |
---|
[100] | 1192 | void discover(const Arc& arc) {} |
---|
[244] | 1193 | /// \brief Called when an arc is examined but its target node is |
---|
[100] | 1194 | /// already discovered. |
---|
[209] | 1195 | /// |
---|
[244] | 1196 | /// This function is called when an arc is examined but its target node is |
---|
[100] | 1197 | /// already discovered. |
---|
| 1198 | void examine(const Arc& arc) {} |
---|
| 1199 | }; |
---|
| 1200 | #else |
---|
| 1201 | template <typename _Digraph> |
---|
| 1202 | struct BfsVisitor { |
---|
| 1203 | typedef _Digraph Digraph; |
---|
| 1204 | typedef typename Digraph::Arc Arc; |
---|
| 1205 | typedef typename Digraph::Node Node; |
---|
[244] | 1206 | void start(const Node&) {} |
---|
| 1207 | void reach(const Node&) {} |
---|
| 1208 | void process(const Node&) {} |
---|
[100] | 1209 | void discover(const Arc&) {} |
---|
| 1210 | void examine(const Arc&) {} |
---|
| 1211 | |
---|
| 1212 | template <typename _Visitor> |
---|
| 1213 | struct Constraints { |
---|
| 1214 | void constraints() { |
---|
[209] | 1215 | Arc arc; |
---|
| 1216 | Node node; |
---|
[244] | 1217 | visitor.start(node); |
---|
| 1218 | visitor.reach(node); |
---|
| 1219 | visitor.process(node); |
---|
[209] | 1220 | visitor.discover(arc); |
---|
| 1221 | visitor.examine(arc); |
---|
[100] | 1222 | } |
---|
| 1223 | _Visitor& visitor; |
---|
| 1224 | }; |
---|
| 1225 | }; |
---|
| 1226 | #endif |
---|
| 1227 | |
---|
| 1228 | /// \brief Default traits class of BfsVisit class. |
---|
| 1229 | /// |
---|
| 1230 | /// Default traits class of BfsVisit class. |
---|
[244] | 1231 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[100] | 1232 | template<class _Digraph> |
---|
| 1233 | struct BfsVisitDefaultTraits { |
---|
| 1234 | |
---|
[244] | 1235 | /// \brief The type of the digraph the algorithm runs on. |
---|
[100] | 1236 | typedef _Digraph Digraph; |
---|
| 1237 | |
---|
| 1238 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1239 | /// |
---|
[100] | 1240 | /// The type of the map that indicates which nodes are reached. |
---|
[244] | 1241 | /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 1242 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1243 | |
---|
[244] | 1244 | /// \brief Instantiates a \ref ReachedMap. |
---|
[100] | 1245 | /// |
---|
[209] | 1246 | /// This function instantiates a \ref ReachedMap. |
---|
[100] | 1247 | /// \param digraph is the digraph, to which |
---|
| 1248 | /// we would like to define the \ref ReachedMap. |
---|
| 1249 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1250 | return new ReachedMap(digraph); |
---|
| 1251 | } |
---|
| 1252 | |
---|
| 1253 | }; |
---|
| 1254 | |
---|
| 1255 | /// \ingroup search |
---|
[209] | 1256 | /// |
---|
[244] | 1257 | /// \brief %BFS algorithm class with visitor interface. |
---|
[209] | 1258 | /// |
---|
[100] | 1259 | /// This class provides an efficient implementation of the %BFS algorithm |
---|
| 1260 | /// with visitor interface. |
---|
| 1261 | /// |
---|
| 1262 | /// The %BfsVisit class provides an alternative interface to the Bfs |
---|
| 1263 | /// class. It works with callback mechanism, the BfsVisit object calls |
---|
[244] | 1264 | /// the member functions of the \c Visitor class on every BFS event. |
---|
[100] | 1265 | /// |
---|
[244] | 1266 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[210] | 1267 | /// The default value is |
---|
[244] | 1268 | /// \ref ListDigraph. The value of _Digraph is not used directly by |
---|
| 1269 | /// \ref BfsVisit, it is only passed to \ref BfsVisitDefaultTraits. |
---|
| 1270 | /// \tparam _Visitor The Visitor type that is used by the algorithm. |
---|
| 1271 | /// \ref BfsVisitor "BfsVisitor<_Digraph>" is an empty visitor, which |
---|
| 1272 | /// does not observe the BFS events. If you want to observe the BFS |
---|
| 1273 | /// events, you should implement your own visitor class. |
---|
[209] | 1274 | /// \tparam _Traits Traits class to set various data types used by the |
---|
[100] | 1275 | /// algorithm. The default traits class is |
---|
| 1276 | /// \ref BfsVisitDefaultTraits "BfsVisitDefaultTraits<_Digraph>". |
---|
| 1277 | /// See \ref BfsVisitDefaultTraits for the documentation of |
---|
[244] | 1278 | /// a BFS visit traits class. |
---|
[100] | 1279 | #ifdef DOXYGEN |
---|
| 1280 | template <typename _Digraph, typename _Visitor, typename _Traits> |
---|
| 1281 | #else |
---|
| 1282 | template <typename _Digraph = ListDigraph, |
---|
[209] | 1283 | typename _Visitor = BfsVisitor<_Digraph>, |
---|
| 1284 | typename _Traits = BfsDefaultTraits<_Digraph> > |
---|
[100] | 1285 | #endif |
---|
| 1286 | class BfsVisit { |
---|
| 1287 | public: |
---|
[209] | 1288 | |
---|
[100] | 1289 | /// \brief \ref Exception for uninitialized parameters. |
---|
| 1290 | /// |
---|
| 1291 | /// This error represents problems in the initialization |
---|
[244] | 1292 | /// of the parameters of the algorithm. |
---|
[100] | 1293 | class UninitializedParameter : public lemon::UninitializedParameter { |
---|
| 1294 | public: |
---|
[209] | 1295 | virtual const char* what() const throw() |
---|
[100] | 1296 | { |
---|
[209] | 1297 | return "lemon::BfsVisit::UninitializedParameter"; |
---|
[100] | 1298 | } |
---|
| 1299 | }; |
---|
| 1300 | |
---|
[244] | 1301 | ///The traits class. |
---|
[100] | 1302 | typedef _Traits Traits; |
---|
| 1303 | |
---|
[244] | 1304 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 1305 | typedef typename Traits::Digraph Digraph; |
---|
| 1306 | |
---|
[244] | 1307 | ///The visitor type used by the algorithm. |
---|
[100] | 1308 | typedef _Visitor Visitor; |
---|
| 1309 | |
---|
[244] | 1310 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 1311 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1312 | |
---|
| 1313 | private: |
---|
| 1314 | |
---|
| 1315 | typedef typename Digraph::Node Node; |
---|
| 1316 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1317 | typedef typename Digraph::Arc Arc; |
---|
| 1318 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1319 | |
---|
[244] | 1320 | //Pointer to the underlying digraph. |
---|
[100] | 1321 | const Digraph *_digraph; |
---|
[244] | 1322 | //Pointer to the visitor object. |
---|
[100] | 1323 | Visitor *_visitor; |
---|
[244] | 1324 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 1325 | ReachedMap *_reached; |
---|
[244] | 1326 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 1327 | bool local_reached; |
---|
| 1328 | |
---|
| 1329 | std::vector<typename Digraph::Node> _list; |
---|
| 1330 | int _list_front, _list_back; |
---|
| 1331 | |
---|
[244] | 1332 | ///Creates the maps if necessary. |
---|
| 1333 | ///\todo Better memory allocation (instead of new). |
---|
[100] | 1334 | void create_maps() { |
---|
| 1335 | if(!_reached) { |
---|
[209] | 1336 | local_reached = true; |
---|
| 1337 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1338 | } |
---|
| 1339 | } |
---|
| 1340 | |
---|
| 1341 | protected: |
---|
| 1342 | |
---|
| 1343 | BfsVisit() {} |
---|
[209] | 1344 | |
---|
[100] | 1345 | public: |
---|
| 1346 | |
---|
| 1347 | typedef BfsVisit Create; |
---|
| 1348 | |
---|
| 1349 | /// \name Named template parameters |
---|
| 1350 | |
---|
| 1351 | ///@{ |
---|
| 1352 | template <class T> |
---|
| 1353 | struct DefReachedMapTraits : public Traits { |
---|
| 1354 | typedef T ReachedMap; |
---|
| 1355 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
[209] | 1356 | throw UninitializedParameter(); |
---|
[100] | 1357 | } |
---|
| 1358 | }; |
---|
[209] | 1359 | /// \brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 1360 | /// ReachedMap type. |
---|
[100] | 1361 | /// |
---|
[244] | 1362 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
---|
[100] | 1363 | template <class T> |
---|
| 1364 | struct DefReachedMap : public BfsVisit< Digraph, Visitor, |
---|
[209] | 1365 | DefReachedMapTraits<T> > { |
---|
[100] | 1366 | typedef BfsVisit< Digraph, Visitor, DefReachedMapTraits<T> > Create; |
---|
| 1367 | }; |
---|
| 1368 | ///@} |
---|
| 1369 | |
---|
[209] | 1370 | public: |
---|
| 1371 | |
---|
[100] | 1372 | /// \brief Constructor. |
---|
| 1373 | /// |
---|
| 1374 | /// Constructor. |
---|
| 1375 | /// |
---|
[244] | 1376 | /// \param digraph The digraph the algorithm runs on. |
---|
| 1377 | /// \param visitor The visitor object of the algorithm. |
---|
[209] | 1378 | BfsVisit(const Digraph& digraph, Visitor& visitor) |
---|
[100] | 1379 | : _digraph(&digraph), _visitor(&visitor), |
---|
[209] | 1380 | _reached(0), local_reached(false) {} |
---|
| 1381 | |
---|
[100] | 1382 | /// \brief Destructor. |
---|
| 1383 | ~BfsVisit() { |
---|
| 1384 | if(local_reached) delete _reached; |
---|
| 1385 | } |
---|
| 1386 | |
---|
[244] | 1387 | /// \brief Sets the map that indicates which nodes are reached. |
---|
[100] | 1388 | /// |
---|
[244] | 1389 | /// Sets the map that indicates which nodes are reached. |
---|
[100] | 1390 | /// If you don't use this function before calling \ref run(), |
---|
[244] | 1391 | /// it will allocate one. The destructor deallocates this |
---|
[100] | 1392 | /// automatically allocated map, of course. |
---|
| 1393 | /// \return <tt> (*this) </tt> |
---|
| 1394 | BfsVisit &reachedMap(ReachedMap &m) { |
---|
| 1395 | if(local_reached) { |
---|
[209] | 1396 | delete _reached; |
---|
| 1397 | local_reached = false; |
---|
[100] | 1398 | } |
---|
| 1399 | _reached = &m; |
---|
| 1400 | return *this; |
---|
| 1401 | } |
---|
| 1402 | |
---|
| 1403 | public: |
---|
[244] | 1404 | |
---|
[100] | 1405 | /// \name Execution control |
---|
| 1406 | /// The simplest way to execute the algorithm is to use |
---|
[244] | 1407 | /// one of the member functions called \ref lemon::BfsVisit::run() |
---|
| 1408 | /// "run()". |
---|
[100] | 1409 | /// \n |
---|
[244] | 1410 | /// If you need more control on the execution, first you must call |
---|
| 1411 | /// \ref lemon::BfsVisit::init() "init()", then you can add several |
---|
| 1412 | /// source nodes with \ref lemon::BfsVisit::addSource() "addSource()". |
---|
| 1413 | /// Finally \ref lemon::BfsVisit::start() "start()" will perform the |
---|
| 1414 | /// actual path computation. |
---|
[100] | 1415 | |
---|
| 1416 | /// @{ |
---|
[244] | 1417 | |
---|
[100] | 1418 | /// \brief Initializes the internal data structures. |
---|
| 1419 | /// |
---|
| 1420 | /// Initializes the internal data structures. |
---|
| 1421 | void init() { |
---|
| 1422 | create_maps(); |
---|
| 1423 | _list.resize(countNodes(*_digraph)); |
---|
| 1424 | _list_front = _list_back = -1; |
---|
| 1425 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
---|
[209] | 1426 | _reached->set(u, false); |
---|
[100] | 1427 | } |
---|
| 1428 | } |
---|
[209] | 1429 | |
---|
[100] | 1430 | /// \brief Adds a new source node. |
---|
| 1431 | /// |
---|
| 1432 | /// Adds a new source node to the set of nodes to be processed. |
---|
| 1433 | void addSource(Node s) { |
---|
| 1434 | if(!(*_reached)[s]) { |
---|
[209] | 1435 | _reached->set(s,true); |
---|
| 1436 | _visitor->start(s); |
---|
| 1437 | _visitor->reach(s); |
---|
[100] | 1438 | _list[++_list_back] = s; |
---|
[209] | 1439 | } |
---|
[100] | 1440 | } |
---|
[209] | 1441 | |
---|
[100] | 1442 | /// \brief Processes the next node. |
---|
| 1443 | /// |
---|
| 1444 | /// Processes the next node. |
---|
| 1445 | /// |
---|
| 1446 | /// \return The processed node. |
---|
| 1447 | /// |
---|
[244] | 1448 | /// \pre The queue must not be empty. |
---|
[209] | 1449 | Node processNextNode() { |
---|
[100] | 1450 | Node n = _list[++_list_front]; |
---|
| 1451 | _visitor->process(n); |
---|
| 1452 | Arc e; |
---|
| 1453 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1454 | Node m = _digraph->target(e); |
---|
| 1455 | if (!(*_reached)[m]) { |
---|
| 1456 | _visitor->discover(e); |
---|
| 1457 | _visitor->reach(m); |
---|
| 1458 | _reached->set(m, true); |
---|
| 1459 | _list[++_list_back] = m; |
---|
| 1460 | } else { |
---|
| 1461 | _visitor->examine(e); |
---|
| 1462 | } |
---|
| 1463 | } |
---|
| 1464 | return n; |
---|
| 1465 | } |
---|
| 1466 | |
---|
| 1467 | /// \brief Processes the next node. |
---|
| 1468 | /// |
---|
[244] | 1469 | /// Processes the next node and checks if the given target node |
---|
[100] | 1470 | /// is reached. If the target node is reachable from the processed |
---|
[244] | 1471 | /// node, then the \c reach parameter will be set to \c true. |
---|
[100] | 1472 | /// |
---|
| 1473 | /// \param target The target node. |
---|
[244] | 1474 | /// \retval reach Indicates if the target node is reached. |
---|
| 1475 | /// It should be initially \c false. |
---|
| 1476 | /// |
---|
[100] | 1477 | /// \return The processed node. |
---|
| 1478 | /// |
---|
[244] | 1479 | /// \pre The queue must not be empty. |
---|
[100] | 1480 | Node processNextNode(Node target, bool& reach) { |
---|
| 1481 | Node n = _list[++_list_front]; |
---|
| 1482 | _visitor->process(n); |
---|
| 1483 | Arc e; |
---|
| 1484 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1485 | Node m = _digraph->target(e); |
---|
| 1486 | if (!(*_reached)[m]) { |
---|
| 1487 | _visitor->discover(e); |
---|
| 1488 | _visitor->reach(m); |
---|
| 1489 | _reached->set(m, true); |
---|
| 1490 | _list[++_list_back] = m; |
---|
| 1491 | reach = reach || (target == m); |
---|
| 1492 | } else { |
---|
| 1493 | _visitor->examine(e); |
---|
| 1494 | } |
---|
| 1495 | } |
---|
| 1496 | return n; |
---|
| 1497 | } |
---|
| 1498 | |
---|
| 1499 | /// \brief Processes the next node. |
---|
| 1500 | /// |
---|
[244] | 1501 | /// Processes the next node and checks if at least one of reached |
---|
| 1502 | /// nodes has \c true value in the \c nm node map. If one node |
---|
| 1503 | /// with \c true value is reachable from the processed node, then the |
---|
| 1504 | /// \c rnode parameter will be set to the first of such nodes. |
---|
[100] | 1505 | /// |
---|
[244] | 1506 | /// \param nm A \c bool (or convertible) node map that indicates the |
---|
| 1507 | /// possible targets. |
---|
[100] | 1508 | /// \retval rnode The reached target node. |
---|
[244] | 1509 | /// It should be initially \c INVALID. |
---|
| 1510 | /// |
---|
[100] | 1511 | /// \return The processed node. |
---|
| 1512 | /// |
---|
[244] | 1513 | /// \pre The queue must not be empty. |
---|
[100] | 1514 | template <typename NM> |
---|
| 1515 | Node processNextNode(const NM& nm, Node& rnode) { |
---|
| 1516 | Node n = _list[++_list_front]; |
---|
| 1517 | _visitor->process(n); |
---|
| 1518 | Arc e; |
---|
| 1519 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1520 | Node m = _digraph->target(e); |
---|
| 1521 | if (!(*_reached)[m]) { |
---|
| 1522 | _visitor->discover(e); |
---|
| 1523 | _visitor->reach(m); |
---|
| 1524 | _reached->set(m, true); |
---|
| 1525 | _list[++_list_back] = m; |
---|
| 1526 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 1527 | } else { |
---|
| 1528 | _visitor->examine(e); |
---|
| 1529 | } |
---|
| 1530 | } |
---|
| 1531 | return n; |
---|
| 1532 | } |
---|
| 1533 | |
---|
[244] | 1534 | /// \brief The next node to be processed. |
---|
[100] | 1535 | /// |
---|
[244] | 1536 | /// Returns the next node to be processed or \c INVALID if the queue |
---|
| 1537 | /// is empty. |
---|
| 1538 | Node nextNode() const { |
---|
[100] | 1539 | return _list_front != _list_back ? _list[_list_front + 1] : INVALID; |
---|
| 1540 | } |
---|
| 1541 | |
---|
| 1542 | /// \brief Returns \c false if there are nodes |
---|
[244] | 1543 | /// to be processed. |
---|
[100] | 1544 | /// |
---|
| 1545 | /// Returns \c false if there are nodes |
---|
[244] | 1546 | /// to be processed in the queue. |
---|
| 1547 | bool emptyQueue() const { return _list_front == _list_back; } |
---|
[100] | 1548 | |
---|
| 1549 | /// \brief Returns the number of the nodes to be processed. |
---|
| 1550 | /// |
---|
| 1551 | /// Returns the number of the nodes to be processed in the queue. |
---|
[244] | 1552 | int queueSize() const { return _list_back - _list_front; } |
---|
[209] | 1553 | |
---|
[100] | 1554 | /// \brief Executes the algorithm. |
---|
| 1555 | /// |
---|
| 1556 | /// Executes the algorithm. |
---|
| 1557 | /// |
---|
[244] | 1558 | /// This method runs the %BFS algorithm from the root node(s) |
---|
| 1559 | /// in order to compute the shortest path to each node. |
---|
| 1560 | /// |
---|
| 1561 | /// The algorithm computes |
---|
| 1562 | /// - the shortest path tree (forest), |
---|
| 1563 | /// - the distance of each node from the root(s). |
---|
| 1564 | /// |
---|
| 1565 | /// \pre init() must be called and at least one root node should be added |
---|
[100] | 1566 | /// with addSource() before using this function. |
---|
[244] | 1567 | /// |
---|
| 1568 | /// \note <tt>b.start()</tt> is just a shortcut of the following code. |
---|
| 1569 | /// \code |
---|
| 1570 | /// while ( !b.emptyQueue() ) { |
---|
| 1571 | /// b.processNextNode(); |
---|
| 1572 | /// } |
---|
| 1573 | /// \endcode |
---|
[100] | 1574 | void start() { |
---|
| 1575 | while ( !emptyQueue() ) processNextNode(); |
---|
| 1576 | } |
---|
[209] | 1577 | |
---|
[244] | 1578 | /// \brief Executes the algorithm until the given target node is reached. |
---|
[100] | 1579 | /// |
---|
[244] | 1580 | /// Executes the algorithm until the given target node is reached. |
---|
[100] | 1581 | /// |
---|
[244] | 1582 | /// This method runs the %BFS algorithm from the root node(s) |
---|
| 1583 | /// in order to compute the shortest path to \c dest. |
---|
| 1584 | /// |
---|
| 1585 | /// The algorithm computes |
---|
| 1586 | /// - the shortest path to \c dest, |
---|
| 1587 | /// - the distance of \c dest from the root(s). |
---|
| 1588 | /// |
---|
| 1589 | /// \pre init() must be called and at least one root node should be |
---|
| 1590 | /// added with addSource() before using this function. |
---|
| 1591 | /// |
---|
| 1592 | /// \note <tt>b.start(t)</tt> is just a shortcut of the following code. |
---|
| 1593 | /// \code |
---|
| 1594 | /// bool reach = false; |
---|
| 1595 | /// while ( !b.emptyQueue() && !reach ) { |
---|
| 1596 | /// b.processNextNode(t, reach); |
---|
| 1597 | /// } |
---|
| 1598 | /// \endcode |
---|
[100] | 1599 | void start(Node dest) { |
---|
| 1600 | bool reach = false; |
---|
| 1601 | while ( !emptyQueue() && !reach ) processNextNode(dest, reach); |
---|
| 1602 | } |
---|
[209] | 1603 | |
---|
[100] | 1604 | /// \brief Executes the algorithm until a condition is met. |
---|
| 1605 | /// |
---|
| 1606 | /// Executes the algorithm until a condition is met. |
---|
| 1607 | /// |
---|
[244] | 1608 | /// This method runs the %BFS algorithm from the root node(s) in |
---|
| 1609 | /// order to compute the shortest path to a node \c v with |
---|
| 1610 | /// <tt>nm[v]</tt> true, if such a node can be found. |
---|
[100] | 1611 | /// |
---|
[244] | 1612 | /// \param nm must be a bool (or convertible) node map. The |
---|
| 1613 | /// algorithm will stop when it reaches a node \c v with |
---|
[100] | 1614 | /// <tt>nm[v]</tt> true. |
---|
| 1615 | /// |
---|
[244] | 1616 | /// \return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 1617 | /// \c INVALID if no such node was found. |
---|
| 1618 | /// |
---|
| 1619 | /// \pre init() must be called and at least one root node should be |
---|
| 1620 | /// added with addSource() before using this function. |
---|
| 1621 | /// |
---|
| 1622 | /// \note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
---|
| 1623 | /// \code |
---|
| 1624 | /// Node rnode = INVALID; |
---|
| 1625 | /// while ( !b.emptyQueue() && rnode == INVALID ) { |
---|
| 1626 | /// b.processNextNode(nm, rnode); |
---|
| 1627 | /// } |
---|
| 1628 | /// return rnode; |
---|
| 1629 | /// \endcode |
---|
[100] | 1630 | template <typename NM> |
---|
| 1631 | Node start(const NM &nm) { |
---|
| 1632 | Node rnode = INVALID; |
---|
| 1633 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 1634 | processNextNode(nm, rnode); |
---|
[100] | 1635 | } |
---|
| 1636 | return rnode; |
---|
| 1637 | } |
---|
| 1638 | |
---|
[244] | 1639 | /// \brief Runs the algorithm from the given node. |
---|
[100] | 1640 | /// |
---|
[244] | 1641 | /// This method runs the %BFS algorithm from node \c s |
---|
| 1642 | /// in order to compute the shortest path to each node. |
---|
| 1643 | /// |
---|
| 1644 | /// The algorithm computes |
---|
| 1645 | /// - the shortest path tree, |
---|
| 1646 | /// - the distance of each node from the root. |
---|
| 1647 | /// |
---|
| 1648 | /// \note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1649 | ///\code |
---|
| 1650 | /// b.init(); |
---|
| 1651 | /// b.addSource(s); |
---|
| 1652 | /// b.start(); |
---|
| 1653 | ///\endcode |
---|
| 1654 | void run(Node s) { |
---|
| 1655 | init(); |
---|
| 1656 | addSource(s); |
---|
| 1657 | start(); |
---|
| 1658 | } |
---|
| 1659 | |
---|
[244] | 1660 | /// \brief Runs the algorithm to visit all nodes in the digraph. |
---|
[209] | 1661 | /// |
---|
[100] | 1662 | /// This method runs the %BFS algorithm in order to |
---|
[244] | 1663 | /// compute the shortest path to each node. |
---|
[100] | 1664 | /// |
---|
[244] | 1665 | /// The algorithm computes |
---|
| 1666 | /// - the shortest path tree (forest), |
---|
| 1667 | /// - the distance of each node from the root(s). |
---|
| 1668 | /// |
---|
| 1669 | /// \note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1670 | ///\code |
---|
| 1671 | /// b.init(); |
---|
[244] | 1672 | /// for (NodeIt n(gr); n != INVALID; ++n) { |
---|
| 1673 | /// if (!b.reached(n)) { |
---|
| 1674 | /// b.addSource(n); |
---|
[100] | 1675 | /// b.start(); |
---|
| 1676 | /// } |
---|
| 1677 | /// } |
---|
| 1678 | ///\endcode |
---|
| 1679 | void run() { |
---|
| 1680 | init(); |
---|
| 1681 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
| 1682 | if (!reached(it)) { |
---|
| 1683 | addSource(it); |
---|
| 1684 | start(); |
---|
| 1685 | } |
---|
| 1686 | } |
---|
| 1687 | } |
---|
[244] | 1688 | |
---|
[100] | 1689 | ///@} |
---|
| 1690 | |
---|
| 1691 | /// \name Query Functions |
---|
| 1692 | /// The result of the %BFS algorithm can be obtained using these |
---|
| 1693 | /// functions.\n |
---|
[244] | 1694 | /// Either \ref lemon::BfsVisit::run() "run()" or |
---|
| 1695 | /// \ref lemon::BfsVisit::start() "start()" must be called before |
---|
| 1696 | /// using them. |
---|
[100] | 1697 | ///@{ |
---|
| 1698 | |
---|
[244] | 1699 | /// \brief Checks if a node is reachable from the root(s). |
---|
[100] | 1700 | /// |
---|
| 1701 | /// Returns \c true if \c v is reachable from the root(s). |
---|
| 1702 | /// \pre Either \ref run() or \ref start() |
---|
| 1703 | /// must be called before using this function. |
---|
| 1704 | bool reached(Node v) { return (*_reached)[v]; } |
---|
[244] | 1705 | |
---|
[100] | 1706 | ///@} |
---|
[244] | 1707 | |
---|
[100] | 1708 | }; |
---|
| 1709 | |
---|
| 1710 | } //END OF NAMESPACE LEMON |
---|
| 1711 | |
---|
| 1712 | #endif |
---|