[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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| 24 | ///\brief Bfs algorithm. |
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| 25 | |
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| 26 | #include <lemon/list_graph.h> |
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| 27 | #include <lemon/bits/path_dump.h> |
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[220] | 28 | #include <lemon/core.h> |
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[100] | 29 | #include <lemon/error.h> |
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| 30 | #include <lemon/maps.h> |
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| 31 | |
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| 32 | namespace lemon { |
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| 33 | |
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| 34 | |
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[209] | 35 | |
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[100] | 36 | ///Default traits class of Bfs class. |
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| 37 | |
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| 38 | ///Default traits class of Bfs class. |
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[157] | 39 | ///\tparam GR Digraph type. |
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[100] | 40 | template<class GR> |
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| 41 | struct BfsDefaultTraits |
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| 42 | { |
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[209] | 43 | ///The digraph type the algorithm runs on. |
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[100] | 44 | typedef GR Digraph; |
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| 45 | ///\brief The type of the map that stores the last |
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| 46 | ///arcs of the shortest paths. |
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[209] | 47 | /// |
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[100] | 48 | ///The type of the map that stores the last |
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| 49 | ///arcs of the shortest paths. |
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| 50 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 51 | /// |
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| 52 | typedef typename Digraph::template NodeMap<typename GR::Arc> PredMap; |
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| 53 | ///Instantiates a PredMap. |
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[209] | 54 | |
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| 55 | ///This function instantiates a \ref PredMap. |
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[100] | 56 | ///\param G is the digraph, to which we would like to define the PredMap. |
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| 57 | ///\todo The digraph alone may be insufficient to initialize |
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[209] | 58 | static PredMap *createPredMap(const GR &G) |
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[100] | 59 | { |
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| 60 | return new PredMap(G); |
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| 61 | } |
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| 62 | ///The type of the map that indicates which nodes are processed. |
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[209] | 63 | |
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[100] | 64 | ///The type of the map that indicates which nodes are processed. |
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| 65 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 66 | ///\todo named parameter to set this type, function to read and write. |
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| 67 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
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| 68 | ///Instantiates a ProcessedMap. |
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[209] | 69 | |
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| 70 | ///This function instantiates a \ref ProcessedMap. |
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[100] | 71 | ///\param g is the digraph, to which |
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| 72 | ///we would like to define the \ref ProcessedMap |
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| 73 | #ifdef DOXYGEN |
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| 74 | static ProcessedMap *createProcessedMap(const GR &g) |
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| 75 | #else |
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| 76 | static ProcessedMap *createProcessedMap(const GR &) |
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| 77 | #endif |
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| 78 | { |
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| 79 | return new ProcessedMap(); |
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| 80 | } |
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| 81 | ///The type of the map that indicates which nodes are reached. |
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[209] | 82 | |
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[100] | 83 | ///The type of the map that indicates which nodes are reached. |
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| 84 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 85 | ///\todo named parameter to set this type, function to read and write. |
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| 86 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
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| 87 | ///Instantiates a ReachedMap. |
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[209] | 88 | |
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| 89 | ///This function instantiates a \ref ReachedMap. |
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[100] | 90 | ///\param G is the digraph, to which |
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| 91 | ///we would like to define the \ref ReachedMap. |
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| 92 | static ReachedMap *createReachedMap(const GR &G) |
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| 93 | { |
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| 94 | return new ReachedMap(G); |
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| 95 | } |
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| 96 | ///The type of the map that stores the dists of the nodes. |
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[209] | 97 | |
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[100] | 98 | ///The type of the map that stores the dists of the nodes. |
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| 99 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
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| 100 | /// |
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| 101 | typedef typename Digraph::template NodeMap<int> DistMap; |
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| 102 | ///Instantiates a DistMap. |
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[209] | 103 | |
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| 104 | ///This function instantiates a \ref DistMap. |
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[210] | 105 | ///\param G is the digraph, to which we would like to define |
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| 106 | ///the \ref DistMap |
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[100] | 107 | static DistMap *createDistMap(const GR &G) |
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| 108 | { |
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| 109 | return new DistMap(G); |
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| 110 | } |
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| 111 | }; |
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[209] | 112 | |
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[100] | 113 | ///%BFS algorithm class. |
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[209] | 114 | |
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[100] | 115 | ///\ingroup search |
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| 116 | ///This class provides an efficient implementation of the %BFS algorithm. |
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| 117 | /// |
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[157] | 118 | ///\tparam GR The digraph type the algorithm runs on. The default value is |
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[100] | 119 | ///\ref ListDigraph. The value of GR is not used directly by Bfs, it |
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| 120 | ///is only passed to \ref BfsDefaultTraits. |
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[157] | 121 | ///\tparam TR Traits class to set various data types used by the algorithm. |
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[100] | 122 | ///The default traits class is |
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| 123 | ///\ref BfsDefaultTraits "BfsDefaultTraits<GR>". |
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| 124 | ///See \ref BfsDefaultTraits for the documentation of |
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| 125 | ///a Bfs traits class. |
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| 126 | |
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| 127 | #ifdef DOXYGEN |
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| 128 | template <typename GR, |
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[209] | 129 | typename TR> |
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[100] | 130 | #else |
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| 131 | template <typename GR=ListDigraph, |
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[209] | 132 | typename TR=BfsDefaultTraits<GR> > |
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[100] | 133 | #endif |
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| 134 | class Bfs { |
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| 135 | public: |
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| 136 | /** |
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| 137 | * \brief \ref Exception for uninitialized parameters. |
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| 138 | * |
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| 139 | * This error represents problems in the initialization |
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| 140 | * of the parameters of the algorithms. |
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| 141 | */ |
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| 142 | class UninitializedParameter : public lemon::UninitializedParameter { |
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| 143 | public: |
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| 144 | virtual const char* what() const throw() { |
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[209] | 145 | return "lemon::Bfs::UninitializedParameter"; |
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[100] | 146 | } |
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| 147 | }; |
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| 148 | |
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| 149 | typedef TR Traits; |
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| 150 | ///The type of the underlying digraph. |
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| 151 | typedef typename TR::Digraph Digraph; |
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[209] | 152 | |
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[100] | 153 | ///\brief The type of the map that stores the last |
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| 154 | ///arcs of the shortest paths. |
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| 155 | typedef typename TR::PredMap PredMap; |
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| 156 | ///The type of the map indicating which nodes are reached. |
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| 157 | typedef typename TR::ReachedMap ReachedMap; |
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| 158 | ///The type of the map indicating which nodes are processed. |
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| 159 | typedef typename TR::ProcessedMap ProcessedMap; |
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| 160 | ///The type of the map that stores the dists of the nodes. |
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| 161 | typedef typename TR::DistMap DistMap; |
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| 162 | private: |
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| 163 | |
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| 164 | typedef typename Digraph::Node Node; |
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| 165 | typedef typename Digraph::NodeIt NodeIt; |
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| 166 | typedef typename Digraph::Arc Arc; |
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| 167 | typedef typename Digraph::OutArcIt OutArcIt; |
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| 168 | |
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| 169 | /// Pointer to the underlying digraph. |
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| 170 | const Digraph *G; |
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| 171 | ///Pointer to the map of predecessors arcs. |
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| 172 | PredMap *_pred; |
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| 173 | ///Indicates if \ref _pred is locally allocated (\c true) or not. |
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| 174 | bool local_pred; |
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| 175 | ///Pointer to the map of distances. |
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| 176 | DistMap *_dist; |
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| 177 | ///Indicates if \ref _dist is locally allocated (\c true) or not. |
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| 178 | bool local_dist; |
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| 179 | ///Pointer to the map of reached status of the nodes. |
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| 180 | ReachedMap *_reached; |
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| 181 | ///Indicates if \ref _reached is locally allocated (\c true) or not. |
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| 182 | bool local_reached; |
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| 183 | ///Pointer to the map of processed status of the nodes. |
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| 184 | ProcessedMap *_processed; |
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| 185 | ///Indicates if \ref _processed is locally allocated (\c true) or not. |
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| 186 | bool local_processed; |
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| 187 | |
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| 188 | std::vector<typename Digraph::Node> _queue; |
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| 189 | int _queue_head,_queue_tail,_queue_next_dist; |
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| 190 | int _curr_dist; |
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| 191 | |
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| 192 | ///Creates the maps if necessary. |
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[209] | 193 | |
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[100] | 194 | ///\todo Better memory allocation (instead of new). |
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[209] | 195 | void create_maps() |
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[100] | 196 | { |
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| 197 | if(!_pred) { |
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[209] | 198 | local_pred = true; |
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| 199 | _pred = Traits::createPredMap(*G); |
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[100] | 200 | } |
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| 201 | if(!_dist) { |
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[209] | 202 | local_dist = true; |
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| 203 | _dist = Traits::createDistMap(*G); |
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[100] | 204 | } |
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| 205 | if(!_reached) { |
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[209] | 206 | local_reached = true; |
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| 207 | _reached = Traits::createReachedMap(*G); |
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[100] | 208 | } |
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| 209 | if(!_processed) { |
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[209] | 210 | local_processed = true; |
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| 211 | _processed = Traits::createProcessedMap(*G); |
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[100] | 212 | } |
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| 213 | } |
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| 214 | |
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| 215 | protected: |
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[209] | 216 | |
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[100] | 217 | Bfs() {} |
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[209] | 218 | |
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[100] | 219 | public: |
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[209] | 220 | |
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[100] | 221 | typedef Bfs Create; |
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| 222 | |
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| 223 | ///\name Named template parameters |
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| 224 | |
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| 225 | ///@{ |
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| 226 | |
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| 227 | template <class T> |
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| 228 | struct DefPredMapTraits : public Traits { |
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| 229 | typedef T PredMap; |
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[209] | 230 | static PredMap *createPredMap(const Digraph &) |
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[100] | 231 | { |
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[209] | 232 | throw UninitializedParameter(); |
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[100] | 233 | } |
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| 234 | }; |
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| 235 | ///\brief \ref named-templ-param "Named parameter" for setting |
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| 236 | ///PredMap type |
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| 237 | /// |
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| 238 | ///\ref named-templ-param "Named parameter" for setting PredMap type |
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| 239 | /// |
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| 240 | template <class T> |
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[209] | 241 | struct DefPredMap : public Bfs< Digraph, DefPredMapTraits<T> > { |
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[100] | 242 | typedef Bfs< Digraph, DefPredMapTraits<T> > Create; |
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| 243 | }; |
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[209] | 244 | |
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[100] | 245 | template <class T> |
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| 246 | struct DefDistMapTraits : public Traits { |
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| 247 | typedef T DistMap; |
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[209] | 248 | static DistMap *createDistMap(const Digraph &) |
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[100] | 249 | { |
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[209] | 250 | throw UninitializedParameter(); |
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[100] | 251 | } |
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| 252 | }; |
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| 253 | ///\brief \ref named-templ-param "Named parameter" for setting |
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| 254 | ///DistMap type |
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| 255 | /// |
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| 256 | ///\ref named-templ-param "Named parameter" for setting DistMap type |
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| 257 | /// |
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| 258 | template <class T> |
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[209] | 259 | struct DefDistMap : public Bfs< Digraph, DefDistMapTraits<T> > { |
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[100] | 260 | typedef Bfs< Digraph, DefDistMapTraits<T> > Create; |
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| 261 | }; |
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[209] | 262 | |
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[100] | 263 | template <class T> |
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| 264 | struct DefReachedMapTraits : public Traits { |
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| 265 | typedef T ReachedMap; |
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[209] | 266 | static ReachedMap *createReachedMap(const Digraph &) |
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[100] | 267 | { |
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[209] | 268 | throw UninitializedParameter(); |
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[100] | 269 | } |
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| 270 | }; |
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| 271 | ///\brief \ref named-templ-param "Named parameter" for setting |
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| 272 | ///ReachedMap type |
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| 273 | /// |
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| 274 | ///\ref named-templ-param "Named parameter" for setting ReachedMap type |
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| 275 | /// |
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| 276 | template <class T> |
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[209] | 277 | struct DefReachedMap : public Bfs< Digraph, DefReachedMapTraits<T> > { |
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[100] | 278 | typedef Bfs< Digraph, DefReachedMapTraits<T> > Create; |
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| 279 | }; |
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[209] | 280 | |
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[100] | 281 | template <class T> |
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| 282 | struct DefProcessedMapTraits : public Traits { |
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| 283 | typedef T ProcessedMap; |
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[209] | 284 | static ProcessedMap *createProcessedMap(const Digraph &) |
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[100] | 285 | { |
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[209] | 286 | throw UninitializedParameter(); |
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[100] | 287 | } |
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| 288 | }; |
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| 289 | ///\brief \ref named-templ-param "Named parameter" for setting |
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| 290 | ///ProcessedMap type |
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| 291 | /// |
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| 292 | ///\ref named-templ-param "Named parameter" for setting ProcessedMap type |
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| 293 | /// |
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| 294 | template <class T> |
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| 295 | struct DefProcessedMap : public Bfs< Digraph, DefProcessedMapTraits<T> > { |
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| 296 | typedef Bfs< Digraph, DefProcessedMapTraits<T> > Create; |
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| 297 | }; |
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[209] | 298 | |
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[100] | 299 | struct DefDigraphProcessedMapTraits : public Traits { |
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| 300 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
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[209] | 301 | static ProcessedMap *createProcessedMap(const Digraph &G) |
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[100] | 302 | { |
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[209] | 303 | return new ProcessedMap(G); |
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[100] | 304 | } |
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| 305 | }; |
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| 306 | ///\brief \ref named-templ-param "Named parameter" |
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| 307 | ///for setting the ProcessedMap type to be Digraph::NodeMap<bool>. |
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| 308 | /// |
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| 309 | ///\ref named-templ-param "Named parameter" |
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| 310 | ///for setting the ProcessedMap type to be Digraph::NodeMap<bool>. |
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| 311 | ///If you don't set it explicitly, it will be automatically allocated. |
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| 312 | template <class T> |
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| 313 | struct DefProcessedMapToBeDefaultMap : |
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[209] | 314 | public Bfs< Digraph, DefDigraphProcessedMapTraits> { |
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[100] | 315 | typedef Bfs< Digraph, DefDigraphProcessedMapTraits> Create; |
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| 316 | }; |
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[209] | 317 | |
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[100] | 318 | ///@} |
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| 319 | |
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[209] | 320 | public: |
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| 321 | |
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[100] | 322 | ///Constructor. |
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[209] | 323 | |
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[100] | 324 | ///\param _G the digraph the algorithm will run on. |
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| 325 | /// |
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| 326 | Bfs(const Digraph& _G) : |
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| 327 | G(&_G), |
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| 328 | _pred(NULL), local_pred(false), |
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| 329 | _dist(NULL), local_dist(false), |
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| 330 | _reached(NULL), local_reached(false), |
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| 331 | _processed(NULL), local_processed(false) |
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| 332 | { } |
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[209] | 333 | |
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[100] | 334 | ///Destructor. |
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[209] | 335 | ~Bfs() |
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[100] | 336 | { |
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| 337 | if(local_pred) delete _pred; |
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| 338 | if(local_dist) delete _dist; |
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| 339 | if(local_reached) delete _reached; |
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| 340 | if(local_processed) delete _processed; |
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| 341 | } |
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| 342 | |
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| 343 | ///Sets the map storing the predecessor arcs. |
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| 344 | |
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| 345 | ///Sets the map storing the predecessor arcs. |
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| 346 | ///If you don't use this function before calling \ref run(), |
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| 347 | ///it will allocate one. The destructor deallocates this |
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| 348 | ///automatically allocated map, of course. |
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| 349 | ///\return <tt> (*this) </tt> |
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[209] | 350 | Bfs &predMap(PredMap &m) |
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[100] | 351 | { |
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| 352 | if(local_pred) { |
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[209] | 353 | delete _pred; |
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| 354 | local_pred=false; |
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[100] | 355 | } |
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| 356 | _pred = &m; |
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| 357 | return *this; |
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| 358 | } |
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| 359 | |
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| 360 | ///Sets the map indicating the reached nodes. |
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| 361 | |
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| 362 | ///Sets the map indicating the reached nodes. |
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| 363 | ///If you don't use this function before calling \ref run(), |
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| 364 | ///it will allocate one. The destructor deallocates this |
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| 365 | ///automatically allocated map, of course. |
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| 366 | ///\return <tt> (*this) </tt> |
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[209] | 367 | Bfs &reachedMap(ReachedMap &m) |
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[100] | 368 | { |
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| 369 | if(local_reached) { |
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[209] | 370 | delete _reached; |
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| 371 | local_reached=false; |
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[100] | 372 | } |
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| 373 | _reached = &m; |
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| 374 | return *this; |
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| 375 | } |
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| 376 | |
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| 377 | ///Sets the map indicating the processed nodes. |
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| 378 | |
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| 379 | ///Sets the map indicating the processed nodes. |
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| 380 | ///If you don't use this function before calling \ref run(), |
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| 381 | ///it will allocate one. The destructor deallocates this |
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| 382 | ///automatically allocated map, of course. |
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| 383 | ///\return <tt> (*this) </tt> |
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[209] | 384 | Bfs &processedMap(ProcessedMap &m) |
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[100] | 385 | { |
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| 386 | if(local_processed) { |
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[209] | 387 | delete _processed; |
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| 388 | local_processed=false; |
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[100] | 389 | } |
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| 390 | _processed = &m; |
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| 391 | return *this; |
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| 392 | } |
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| 393 | |
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| 394 | ///Sets the map storing the distances calculated by the algorithm. |
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| 395 | |
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| 396 | ///Sets the map storing the distances calculated by the algorithm. |
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| 397 | ///If you don't use this function before calling \ref run(), |
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| 398 | ///it will allocate one. The destructor deallocates this |
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| 399 | ///automatically allocated map, of course. |
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| 400 | ///\return <tt> (*this) </tt> |
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[209] | 401 | Bfs &distMap(DistMap &m) |
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[100] | 402 | { |
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| 403 | if(local_dist) { |
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[209] | 404 | delete _dist; |
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| 405 | local_dist=false; |
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[100] | 406 | } |
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| 407 | _dist = &m; |
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| 408 | return *this; |
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| 409 | } |
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| 410 | |
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| 411 | public: |
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| 412 | ///\name Execution control |
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| 413 | ///The simplest way to execute the algorithm is to use |
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| 414 | ///one of the member functions called \c run(...). |
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| 415 | ///\n |
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| 416 | ///If you need more control on the execution, |
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| 417 | ///first you must call \ref init(), then you can add several source nodes |
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| 418 | ///with \ref addSource(). |
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| 419 | ///Finally \ref start() will perform the actual path |
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| 420 | ///computation. |
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| 421 | |
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| 422 | ///@{ |
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| 423 | |
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| 424 | ///\brief Initializes the internal data structures. |
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| 425 | /// |
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| 426 | ///Initializes the internal data structures. |
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| 427 | /// |
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| 428 | void init() |
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| 429 | { |
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| 430 | create_maps(); |
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| 431 | _queue.resize(countNodes(*G)); |
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| 432 | _queue_head=_queue_tail=0; |
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| 433 | _curr_dist=1; |
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| 434 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
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[209] | 435 | _pred->set(u,INVALID); |
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| 436 | _reached->set(u,false); |
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| 437 | _processed->set(u,false); |
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[100] | 438 | } |
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| 439 | } |
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[209] | 440 | |
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[100] | 441 | ///Adds a new source node. |
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| 442 | |
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| 443 | ///Adds a new source node to the set of nodes to be processed. |
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| 444 | /// |
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| 445 | void addSource(Node s) |
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| 446 | { |
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| 447 | if(!(*_reached)[s]) |
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[209] | 448 | { |
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| 449 | _reached->set(s,true); |
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| 450 | _pred->set(s,INVALID); |
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| 451 | _dist->set(s,0); |
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| 452 | _queue[_queue_head++]=s; |
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| 453 | _queue_next_dist=_queue_head; |
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| 454 | } |
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[100] | 455 | } |
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[209] | 456 | |
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[100] | 457 | ///Processes the next node. |
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| 458 | |
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| 459 | ///Processes the next node. |
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| 460 | /// |
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| 461 | ///\return The processed node. |
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| 462 | /// |
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| 463 | ///\warning The queue must not be empty! |
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| 464 | Node processNextNode() |
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| 465 | { |
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| 466 | if(_queue_tail==_queue_next_dist) { |
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[209] | 467 | _curr_dist++; |
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| 468 | _queue_next_dist=_queue_head; |
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[100] | 469 | } |
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| 470 | Node n=_queue[_queue_tail++]; |
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| 471 | _processed->set(n,true); |
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| 472 | Node m; |
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| 473 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
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[209] | 474 | if(!(*_reached)[m=G->target(e)]) { |
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| 475 | _queue[_queue_head++]=m; |
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| 476 | _reached->set(m,true); |
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| 477 | _pred->set(m,e); |
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| 478 | _dist->set(m,_curr_dist); |
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| 479 | } |
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[100] | 480 | return n; |
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| 481 | } |
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| 482 | |
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| 483 | ///Processes the next node. |
---|
| 484 | |
---|
| 485 | ///Processes the next node. And checks that the given target node |
---|
| 486 | ///is reached. If the target node is reachable from the processed |
---|
| 487 | ///node then the reached parameter will be set true. The reached |
---|
| 488 | ///parameter should be initially false. |
---|
| 489 | /// |
---|
| 490 | ///\param target The target node. |
---|
| 491 | ///\retval reach Indicates that the target node is reached. |
---|
| 492 | ///\return The processed node. |
---|
| 493 | /// |
---|
| 494 | ///\warning The queue must not be empty! |
---|
| 495 | Node processNextNode(Node target, bool& reach) |
---|
| 496 | { |
---|
| 497 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 498 | _curr_dist++; |
---|
| 499 | _queue_next_dist=_queue_head; |
---|
[100] | 500 | } |
---|
| 501 | Node n=_queue[_queue_tail++]; |
---|
| 502 | _processed->set(n,true); |
---|
| 503 | Node m; |
---|
| 504 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 505 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 506 | _queue[_queue_head++]=m; |
---|
| 507 | _reached->set(m,true); |
---|
| 508 | _pred->set(m,e); |
---|
| 509 | _dist->set(m,_curr_dist); |
---|
[100] | 510 | reach = reach || (target == m); |
---|
[209] | 511 | } |
---|
[100] | 512 | return n; |
---|
| 513 | } |
---|
| 514 | |
---|
| 515 | ///Processes the next node. |
---|
| 516 | |
---|
| 517 | ///Processes the next node. And checks that at least one of |
---|
| 518 | ///reached node has true value in the \c nm node map. If one node |
---|
| 519 | ///with true value is reachable from the processed node then the |
---|
| 520 | ///rnode parameter will be set to the first of such nodes. |
---|
| 521 | /// |
---|
| 522 | ///\param nm The node map of possible targets. |
---|
| 523 | ///\retval rnode The reached target node. |
---|
| 524 | ///\return The processed node. |
---|
| 525 | /// |
---|
| 526 | ///\warning The queue must not be empty! |
---|
| 527 | template<class NM> |
---|
| 528 | Node processNextNode(const NM& nm, Node& rnode) |
---|
| 529 | { |
---|
| 530 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 531 | _curr_dist++; |
---|
| 532 | _queue_next_dist=_queue_head; |
---|
[100] | 533 | } |
---|
| 534 | Node n=_queue[_queue_tail++]; |
---|
| 535 | _processed->set(n,true); |
---|
| 536 | Node m; |
---|
| 537 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 538 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 539 | _queue[_queue_head++]=m; |
---|
| 540 | _reached->set(m,true); |
---|
| 541 | _pred->set(m,e); |
---|
| 542 | _dist->set(m,_curr_dist); |
---|
| 543 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 544 | } |
---|
[100] | 545 | return n; |
---|
| 546 | } |
---|
[209] | 547 | |
---|
[100] | 548 | ///Next node to be processed. |
---|
| 549 | |
---|
| 550 | ///Next node to be processed. |
---|
| 551 | /// |
---|
| 552 | ///\return The next node to be processed or INVALID if the queue is |
---|
| 553 | /// empty. |
---|
| 554 | Node nextNode() |
---|
[209] | 555 | { |
---|
[100] | 556 | return _queue_tail<_queue_head?_queue[_queue_tail]:INVALID; |
---|
| 557 | } |
---|
[209] | 558 | |
---|
[100] | 559 | ///\brief Returns \c false if there are nodes |
---|
| 560 | ///to be processed in the queue |
---|
| 561 | /// |
---|
| 562 | ///Returns \c false if there are nodes |
---|
| 563 | ///to be processed in the queue |
---|
| 564 | bool emptyQueue() { return _queue_tail==_queue_head; } |
---|
| 565 | ///Returns the number of the nodes to be processed. |
---|
[209] | 566 | |
---|
[100] | 567 | ///Returns the number of the nodes to be processed in the queue. |
---|
| 568 | int queueSize() { return _queue_head-_queue_tail; } |
---|
[209] | 569 | |
---|
[100] | 570 | ///Executes the algorithm. |
---|
| 571 | |
---|
| 572 | ///Executes the algorithm. |
---|
| 573 | /// |
---|
| 574 | ///\pre init() must be called and at least one node should be added |
---|
| 575 | ///with addSource() before using this function. |
---|
| 576 | /// |
---|
| 577 | ///This method runs the %BFS algorithm from the root node(s) |
---|
| 578 | ///in order to |
---|
| 579 | ///compute the |
---|
| 580 | ///shortest path to each node. The algorithm computes |
---|
| 581 | ///- The shortest path tree. |
---|
| 582 | ///- The distance of each node from the root(s). |
---|
| 583 | void start() |
---|
| 584 | { |
---|
| 585 | while ( !emptyQueue() ) processNextNode(); |
---|
| 586 | } |
---|
[209] | 587 | |
---|
[100] | 588 | ///Executes the algorithm until \c dest is reached. |
---|
| 589 | |
---|
| 590 | ///Executes the algorithm until \c dest is reached. |
---|
| 591 | /// |
---|
| 592 | ///\pre init() must be called and at least one node should be added |
---|
| 593 | ///with addSource() before using this function. |
---|
| 594 | /// |
---|
| 595 | ///This method runs the %BFS algorithm from the root node(s) |
---|
| 596 | ///in order to compute the shortest path to \c dest. |
---|
| 597 | ///The algorithm computes |
---|
| 598 | ///- The shortest path to \c dest. |
---|
| 599 | ///- The distance of \c dest from the root(s). |
---|
| 600 | void start(Node dest) |
---|
| 601 | { |
---|
| 602 | bool reach = false; |
---|
| 603 | while ( !emptyQueue() && !reach ) processNextNode(dest, reach); |
---|
| 604 | } |
---|
[209] | 605 | |
---|
[100] | 606 | ///Executes the algorithm until a condition is met. |
---|
| 607 | |
---|
| 608 | ///Executes the algorithm until a condition is met. |
---|
| 609 | /// |
---|
| 610 | ///\pre init() must be called and at least one node should be added |
---|
| 611 | ///with addSource() before using this function. |
---|
| 612 | /// |
---|
| 613 | ///\param nm must be a bool (or convertible) node map. The |
---|
| 614 | ///algorithm will stop when it reaches a node \c v with |
---|
| 615 | /// <tt>nm[v]</tt> true. |
---|
| 616 | /// |
---|
| 617 | ///\return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 618 | ///\c INVALID if no such node was found. |
---|
| 619 | template<class NM> |
---|
| 620 | Node start(const NM &nm) |
---|
| 621 | { |
---|
| 622 | Node rnode = INVALID; |
---|
| 623 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 624 | processNextNode(nm, rnode); |
---|
[100] | 625 | } |
---|
| 626 | return rnode; |
---|
| 627 | } |
---|
[209] | 628 | |
---|
[100] | 629 | ///Runs %BFS algorithm from node \c s. |
---|
[209] | 630 | |
---|
[100] | 631 | ///This method runs the %BFS algorithm from a root node \c s |
---|
| 632 | ///in order to |
---|
| 633 | ///compute the |
---|
| 634 | ///shortest path to each node. The algorithm computes |
---|
| 635 | ///- The shortest path tree. |
---|
| 636 | ///- The distance of each node from the root. |
---|
| 637 | /// |
---|
| 638 | ///\note b.run(s) is just a shortcut of the following code. |
---|
| 639 | ///\code |
---|
| 640 | /// b.init(); |
---|
| 641 | /// b.addSource(s); |
---|
| 642 | /// b.start(); |
---|
| 643 | ///\endcode |
---|
| 644 | void run(Node s) { |
---|
| 645 | init(); |
---|
| 646 | addSource(s); |
---|
| 647 | start(); |
---|
| 648 | } |
---|
[209] | 649 | |
---|
[100] | 650 | ///Finds the shortest path between \c s and \c t. |
---|
[209] | 651 | |
---|
[100] | 652 | ///Finds the shortest path between \c s and \c t. |
---|
| 653 | /// |
---|
| 654 | ///\return The length of the shortest s---t path if there exists one, |
---|
| 655 | ///0 otherwise. |
---|
| 656 | ///\note Apart from the return value, b.run(s) is |
---|
| 657 | ///just a shortcut of the following code. |
---|
| 658 | ///\code |
---|
| 659 | /// b.init(); |
---|
| 660 | /// b.addSource(s); |
---|
| 661 | /// b.start(t); |
---|
| 662 | ///\endcode |
---|
| 663 | int run(Node s,Node t) { |
---|
| 664 | init(); |
---|
| 665 | addSource(s); |
---|
| 666 | start(t); |
---|
| 667 | return reached(t) ? _curr_dist : 0; |
---|
| 668 | } |
---|
[209] | 669 | |
---|
[100] | 670 | ///@} |
---|
| 671 | |
---|
| 672 | ///\name Query Functions |
---|
| 673 | ///The result of the %BFS algorithm can be obtained using these |
---|
| 674 | ///functions.\n |
---|
| 675 | ///Before the use of these functions, |
---|
| 676 | ///either run() or start() must be calleb. |
---|
[209] | 677 | |
---|
[100] | 678 | ///@{ |
---|
| 679 | |
---|
| 680 | typedef PredMapPath<Digraph, PredMap> Path; |
---|
| 681 | |
---|
| 682 | ///Gives back the shortest path. |
---|
[209] | 683 | |
---|
[100] | 684 | ///Gives back the shortest path. |
---|
| 685 | ///\pre The \c t should be reachable from the source. |
---|
[209] | 686 | Path path(Node t) |
---|
[100] | 687 | { |
---|
| 688 | return Path(*G, *_pred, t); |
---|
| 689 | } |
---|
| 690 | |
---|
| 691 | ///The distance of a node from the root(s). |
---|
| 692 | |
---|
| 693 | ///Returns the distance of a node from the root(s). |
---|
| 694 | ///\pre \ref run() must be called before using this function. |
---|
| 695 | ///\warning If node \c v in unreachable from the root(s) the return value |
---|
| 696 | ///of this function is undefined. |
---|
| 697 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 698 | |
---|
| 699 | ///Returns the 'previous arc' of the shortest path tree. |
---|
| 700 | |
---|
| 701 | ///For a node \c v it returns the 'previous arc' |
---|
| 702 | ///of the shortest path tree, |
---|
| 703 | ///i.e. it returns the last arc of a shortest path from the root(s) to \c |
---|
| 704 | ///v. It is \ref INVALID |
---|
| 705 | ///if \c v is unreachable from the root(s) or \c v is a root. The |
---|
| 706 | ///shortest path tree used here is equal to the shortest path tree used in |
---|
| 707 | ///\ref predNode(). |
---|
| 708 | ///\pre Either \ref run() or \ref start() must be called before using |
---|
| 709 | ///this function. |
---|
| 710 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 711 | |
---|
| 712 | ///Returns the 'previous node' of the shortest path tree. |
---|
| 713 | |
---|
| 714 | ///For a node \c v it returns the 'previous node' |
---|
| 715 | ///of the shortest path tree, |
---|
| 716 | ///i.e. it returns the last but one node from a shortest path from the |
---|
| 717 | ///root(a) to \c /v. |
---|
| 718 | ///It is INVALID if \c v is unreachable from the root(s) or |
---|
| 719 | ///if \c v itself a root. |
---|
| 720 | ///The shortest path tree used here is equal to the shortest path |
---|
| 721 | ///tree used in \ref predArc(). |
---|
| 722 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 723 | ///using this function. |
---|
| 724 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
[209] | 725 | G->source((*_pred)[v]); } |
---|
| 726 | |
---|
[100] | 727 | ///Returns a reference to the NodeMap of distances. |
---|
| 728 | |
---|
| 729 | ///Returns a reference to the NodeMap of distances. |
---|
| 730 | ///\pre Either \ref run() or \ref init() must |
---|
| 731 | ///be called before using this function. |
---|
| 732 | const DistMap &distMap() const { return *_dist;} |
---|
[209] | 733 | |
---|
[100] | 734 | ///Returns a reference to the shortest path tree map. |
---|
| 735 | |
---|
| 736 | ///Returns a reference to the NodeMap of the arcs of the |
---|
| 737 | ///shortest path tree. |
---|
| 738 | ///\pre Either \ref run() or \ref init() |
---|
| 739 | ///must be called before using this function. |
---|
| 740 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 741 | |
---|
[100] | 742 | ///Checks if a node is reachable from the root. |
---|
| 743 | |
---|
| 744 | ///Returns \c true if \c v is reachable from the root. |
---|
| 745 | ///\warning The source nodes are indicated as unreached. |
---|
| 746 | ///\pre Either \ref run() or \ref start() |
---|
| 747 | ///must be called before using this function. |
---|
| 748 | /// |
---|
| 749 | bool reached(Node v) { return (*_reached)[v]; } |
---|
[209] | 750 | |
---|
[100] | 751 | ///@} |
---|
| 752 | }; |
---|
| 753 | |
---|
| 754 | ///Default traits class of Bfs function. |
---|
| 755 | |
---|
| 756 | ///Default traits class of Bfs function. |
---|
[157] | 757 | ///\tparam GR Digraph type. |
---|
[100] | 758 | template<class GR> |
---|
| 759 | struct BfsWizardDefaultTraits |
---|
| 760 | { |
---|
[209] | 761 | ///The digraph type the algorithm runs on. |
---|
[100] | 762 | typedef GR Digraph; |
---|
| 763 | ///\brief The type of the map that stores the last |
---|
| 764 | ///arcs of the shortest paths. |
---|
[209] | 765 | /// |
---|
[100] | 766 | ///The type of the map that stores the last |
---|
| 767 | ///arcs of the shortest paths. |
---|
| 768 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 769 | /// |
---|
| 770 | typedef NullMap<typename Digraph::Node,typename GR::Arc> PredMap; |
---|
| 771 | ///Instantiates a PredMap. |
---|
[209] | 772 | |
---|
| 773 | ///This function instantiates a \ref PredMap. |
---|
[100] | 774 | ///\param g is the digraph, to which we would like to define the PredMap. |
---|
| 775 | ///\todo The digraph alone may be insufficient to initialize |
---|
| 776 | #ifdef DOXYGEN |
---|
[209] | 777 | static PredMap *createPredMap(const GR &g) |
---|
[100] | 778 | #else |
---|
[209] | 779 | static PredMap *createPredMap(const GR &) |
---|
[100] | 780 | #endif |
---|
| 781 | { |
---|
| 782 | return new PredMap(); |
---|
| 783 | } |
---|
| 784 | |
---|
| 785 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 786 | |
---|
[100] | 787 | ///The type of the map that indicates which nodes are processed. |
---|
| 788 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 789 | ///\todo named parameter to set this type, function to read and write. |
---|
| 790 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
| 791 | ///Instantiates a ProcessedMap. |
---|
[209] | 792 | |
---|
| 793 | ///This function instantiates a \ref ProcessedMap. |
---|
[100] | 794 | ///\param g is the digraph, to which |
---|
| 795 | ///we would like to define the \ref ProcessedMap |
---|
| 796 | #ifdef DOXYGEN |
---|
| 797 | static ProcessedMap *createProcessedMap(const GR &g) |
---|
| 798 | #else |
---|
| 799 | static ProcessedMap *createProcessedMap(const GR &) |
---|
| 800 | #endif |
---|
| 801 | { |
---|
| 802 | return new ProcessedMap(); |
---|
| 803 | } |
---|
| 804 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 805 | |
---|
[100] | 806 | ///The type of the map that indicates which nodes are reached. |
---|
| 807 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 808 | ///\todo named parameter to set this type, function to read and write. |
---|
| 809 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 810 | ///Instantiates a ReachedMap. |
---|
[209] | 811 | |
---|
| 812 | ///This function instantiates a \ref ReachedMap. |
---|
[100] | 813 | ///\param G is the digraph, to which |
---|
| 814 | ///we would like to define the \ref ReachedMap. |
---|
| 815 | static ReachedMap *createReachedMap(const GR &G) |
---|
| 816 | { |
---|
| 817 | return new ReachedMap(G); |
---|
| 818 | } |
---|
| 819 | ///The type of the map that stores the dists of the nodes. |
---|
[209] | 820 | |
---|
[100] | 821 | ///The type of the map that stores the dists of the nodes. |
---|
| 822 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 823 | /// |
---|
| 824 | typedef NullMap<typename Digraph::Node,int> DistMap; |
---|
| 825 | ///Instantiates a DistMap. |
---|
[209] | 826 | |
---|
| 827 | ///This function instantiates a \ref DistMap. |
---|
[210] | 828 | ///\param g is the digraph, to which we would like to define |
---|
| 829 | ///the \ref DistMap |
---|
[100] | 830 | #ifdef DOXYGEN |
---|
| 831 | static DistMap *createDistMap(const GR &g) |
---|
| 832 | #else |
---|
| 833 | static DistMap *createDistMap(const GR &) |
---|
| 834 | #endif |
---|
| 835 | { |
---|
| 836 | return new DistMap(); |
---|
| 837 | } |
---|
| 838 | }; |
---|
[209] | 839 | |
---|
[100] | 840 | /// Default traits used by \ref BfsWizard |
---|
| 841 | |
---|
| 842 | /// To make it easier to use Bfs algorithm |
---|
| 843 | ///we have created a wizard class. |
---|
| 844 | /// This \ref BfsWizard class needs default traits, |
---|
| 845 | ///as well as the \ref Bfs class. |
---|
| 846 | /// The \ref BfsWizardBase is a class to be the default traits of the |
---|
| 847 | /// \ref BfsWizard class. |
---|
| 848 | template<class GR> |
---|
| 849 | class BfsWizardBase : public BfsWizardDefaultTraits<GR> |
---|
| 850 | { |
---|
| 851 | |
---|
| 852 | typedef BfsWizardDefaultTraits<GR> Base; |
---|
| 853 | protected: |
---|
| 854 | /// Type of the nodes in the digraph. |
---|
| 855 | typedef typename Base::Digraph::Node Node; |
---|
| 856 | |
---|
| 857 | /// Pointer to the underlying digraph. |
---|
| 858 | void *_g; |
---|
| 859 | ///Pointer to the map of reached nodes. |
---|
| 860 | void *_reached; |
---|
| 861 | ///Pointer to the map of processed nodes. |
---|
| 862 | void *_processed; |
---|
| 863 | ///Pointer to the map of predecessors arcs. |
---|
| 864 | void *_pred; |
---|
| 865 | ///Pointer to the map of distances. |
---|
| 866 | void *_dist; |
---|
| 867 | ///Pointer to the source node. |
---|
| 868 | Node _source; |
---|
[209] | 869 | |
---|
[100] | 870 | public: |
---|
| 871 | /// Constructor. |
---|
[209] | 872 | |
---|
[100] | 873 | /// This constructor does not require parameters, therefore it initiates |
---|
| 874 | /// all of the attributes to default values (0, INVALID). |
---|
| 875 | BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[209] | 876 | _dist(0), _source(INVALID) {} |
---|
[100] | 877 | |
---|
| 878 | /// Constructor. |
---|
[209] | 879 | |
---|
[100] | 880 | /// This constructor requires some parameters, |
---|
| 881 | /// listed in the parameters list. |
---|
| 882 | /// Others are initiated to 0. |
---|
| 883 | /// \param g is the initial value of \ref _g |
---|
| 884 | /// \param s is the initial value of \ref _source |
---|
| 885 | BfsWizardBase(const GR &g, Node s=INVALID) : |
---|
[209] | 886 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
---|
[100] | 887 | _reached(0), _processed(0), _pred(0), _dist(0), _source(s) {} |
---|
| 888 | |
---|
| 889 | }; |
---|
[209] | 890 | |
---|
[100] | 891 | /// A class to make the usage of Bfs algorithm easier |
---|
| 892 | |
---|
| 893 | /// This class is created to make it easier to use Bfs algorithm. |
---|
| 894 | /// It uses the functions and features of the plain \ref Bfs, |
---|
| 895 | /// but it is much simpler to use it. |
---|
| 896 | /// |
---|
| 897 | /// Simplicity means that the way to change the types defined |
---|
| 898 | /// in the traits class is based on functions that returns the new class |
---|
| 899 | /// and not on templatable built-in classes. |
---|
| 900 | /// When using the plain \ref Bfs |
---|
| 901 | /// the new class with the modified type comes from |
---|
| 902 | /// the original class by using the :: |
---|
| 903 | /// operator. In the case of \ref BfsWizard only |
---|
| 904 | /// a function have to be called and it will |
---|
| 905 | /// return the needed class. |
---|
| 906 | /// |
---|
| 907 | /// It does not have own \ref run method. When its \ref run method is called |
---|
| 908 | /// it initiates a plain \ref Bfs class, and calls the \ref Bfs::run |
---|
| 909 | /// method of it. |
---|
| 910 | template<class TR> |
---|
| 911 | class BfsWizard : public TR |
---|
| 912 | { |
---|
| 913 | typedef TR Base; |
---|
| 914 | |
---|
| 915 | ///The type of the underlying digraph. |
---|
| 916 | typedef typename TR::Digraph Digraph; |
---|
| 917 | //\e |
---|
| 918 | typedef typename Digraph::Node Node; |
---|
| 919 | //\e |
---|
| 920 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 921 | //\e |
---|
| 922 | typedef typename Digraph::Arc Arc; |
---|
| 923 | //\e |
---|
| 924 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
[209] | 925 | |
---|
[100] | 926 | ///\brief The type of the map that stores |
---|
| 927 | ///the reached nodes |
---|
| 928 | typedef typename TR::ReachedMap ReachedMap; |
---|
| 929 | ///\brief The type of the map that stores |
---|
| 930 | ///the processed nodes |
---|
| 931 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
| 932 | ///\brief The type of the map that stores the last |
---|
| 933 | ///arcs of the shortest paths. |
---|
| 934 | typedef typename TR::PredMap PredMap; |
---|
| 935 | ///The type of the map that stores the dists of the nodes. |
---|
| 936 | typedef typename TR::DistMap DistMap; |
---|
| 937 | |
---|
| 938 | public: |
---|
| 939 | /// Constructor. |
---|
| 940 | BfsWizard() : TR() {} |
---|
| 941 | |
---|
| 942 | /// Constructor that requires parameters. |
---|
| 943 | |
---|
| 944 | /// Constructor that requires parameters. |
---|
| 945 | /// These parameters will be the default values for the traits class. |
---|
| 946 | BfsWizard(const Digraph &g, Node s=INVALID) : |
---|
| 947 | TR(g,s) {} |
---|
| 948 | |
---|
| 949 | ///Copy constructor |
---|
| 950 | BfsWizard(const TR &b) : TR(b) {} |
---|
| 951 | |
---|
| 952 | ~BfsWizard() {} |
---|
| 953 | |
---|
| 954 | ///Runs Bfs algorithm from a given node. |
---|
[209] | 955 | |
---|
[100] | 956 | ///Runs Bfs algorithm from a given node. |
---|
| 957 | ///The node can be given by the \ref source function. |
---|
| 958 | void run() |
---|
| 959 | { |
---|
| 960 | if(Base::_source==INVALID) throw UninitializedParameter(); |
---|
| 961 | Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 962 | if(Base::_reached) |
---|
[209] | 963 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 964 | if(Base::_processed) |
---|
[100] | 965 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
[209] | 966 | if(Base::_pred) |
---|
[100] | 967 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
[209] | 968 | if(Base::_dist) |
---|
[100] | 969 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 970 | alg.run(Base::_source); |
---|
| 971 | } |
---|
| 972 | |
---|
| 973 | ///Runs Bfs algorithm from the given node. |
---|
| 974 | |
---|
| 975 | ///Runs Bfs algorithm from the given node. |
---|
| 976 | ///\param s is the given source. |
---|
| 977 | void run(Node s) |
---|
| 978 | { |
---|
| 979 | Base::_source=s; |
---|
| 980 | run(); |
---|
| 981 | } |
---|
| 982 | |
---|
| 983 | template<class T> |
---|
| 984 | struct DefPredMapBase : public Base { |
---|
| 985 | typedef T PredMap; |
---|
| 986 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
| 987 | DefPredMapBase(const TR &b) : TR(b) {} |
---|
| 988 | }; |
---|
[209] | 989 | |
---|
[100] | 990 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 991 | ///function for setting PredMap |
---|
| 992 | /// |
---|
| 993 | /// \ref named-templ-param "Named parameter" |
---|
| 994 | ///function for setting PredMap |
---|
| 995 | /// |
---|
| 996 | template<class T> |
---|
[209] | 997 | BfsWizard<DefPredMapBase<T> > predMap(const T &t) |
---|
[100] | 998 | { |
---|
| 999 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1000 | return BfsWizard<DefPredMapBase<T> >(*this); |
---|
| 1001 | } |
---|
[209] | 1002 | |
---|
| 1003 | |
---|
[100] | 1004 | template<class T> |
---|
| 1005 | struct DefReachedMapBase : public Base { |
---|
| 1006 | typedef T ReachedMap; |
---|
| 1007 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
| 1008 | DefReachedMapBase(const TR &b) : TR(b) {} |
---|
| 1009 | }; |
---|
[209] | 1010 | |
---|
[100] | 1011 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1012 | ///function for setting ReachedMap |
---|
| 1013 | /// |
---|
| 1014 | /// \ref named-templ-param "Named parameter" |
---|
| 1015 | ///function for setting ReachedMap |
---|
| 1016 | /// |
---|
| 1017 | template<class T> |
---|
[209] | 1018 | BfsWizard<DefReachedMapBase<T> > reachedMap(const T &t) |
---|
[100] | 1019 | { |
---|
[158] | 1020 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[100] | 1021 | return BfsWizard<DefReachedMapBase<T> >(*this); |
---|
| 1022 | } |
---|
[209] | 1023 | |
---|
[100] | 1024 | |
---|
| 1025 | template<class T> |
---|
| 1026 | struct DefProcessedMapBase : public Base { |
---|
| 1027 | typedef T ProcessedMap; |
---|
| 1028 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
| 1029 | DefProcessedMapBase(const TR &b) : TR(b) {} |
---|
| 1030 | }; |
---|
[209] | 1031 | |
---|
[100] | 1032 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1033 | ///function for setting ProcessedMap |
---|
| 1034 | /// |
---|
| 1035 | /// \ref named-templ-param "Named parameter" |
---|
| 1036 | ///function for setting ProcessedMap |
---|
| 1037 | /// |
---|
| 1038 | template<class T> |
---|
[209] | 1039 | BfsWizard<DefProcessedMapBase<T> > processedMap(const T &t) |
---|
[100] | 1040 | { |
---|
[158] | 1041 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[100] | 1042 | return BfsWizard<DefProcessedMapBase<T> >(*this); |
---|
| 1043 | } |
---|
[209] | 1044 | |
---|
| 1045 | |
---|
[100] | 1046 | template<class T> |
---|
| 1047 | struct DefDistMapBase : public Base { |
---|
| 1048 | typedef T DistMap; |
---|
| 1049 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
| 1050 | DefDistMapBase(const TR &b) : TR(b) {} |
---|
| 1051 | }; |
---|
[209] | 1052 | |
---|
[100] | 1053 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1054 | ///function for setting DistMap type |
---|
| 1055 | /// |
---|
| 1056 | /// \ref named-templ-param "Named parameter" |
---|
| 1057 | ///function for setting DistMap type |
---|
| 1058 | /// |
---|
| 1059 | template<class T> |
---|
[209] | 1060 | BfsWizard<DefDistMapBase<T> > distMap(const T &t) |
---|
[100] | 1061 | { |
---|
| 1062 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
| 1063 | return BfsWizard<DefDistMapBase<T> >(*this); |
---|
| 1064 | } |
---|
[209] | 1065 | |
---|
[100] | 1066 | /// Sets the source node, from which the Bfs algorithm runs. |
---|
| 1067 | |
---|
| 1068 | /// Sets the source node, from which the Bfs algorithm runs. |
---|
| 1069 | /// \param s is the source node. |
---|
[209] | 1070 | BfsWizard<TR> &source(Node s) |
---|
[100] | 1071 | { |
---|
| 1072 | Base::_source=s; |
---|
| 1073 | return *this; |
---|
| 1074 | } |
---|
[209] | 1075 | |
---|
[100] | 1076 | }; |
---|
[209] | 1077 | |
---|
[100] | 1078 | ///Function type interface for Bfs algorithm. |
---|
| 1079 | |
---|
| 1080 | /// \ingroup search |
---|
| 1081 | ///Function type interface for Bfs algorithm. |
---|
| 1082 | /// |
---|
| 1083 | ///This function also has several |
---|
| 1084 | ///\ref named-templ-func-param "named parameters", |
---|
| 1085 | ///they are declared as the members of class \ref BfsWizard. |
---|
| 1086 | ///The following |
---|
| 1087 | ///example shows how to use these parameters. |
---|
| 1088 | ///\code |
---|
| 1089 | /// bfs(g,source).predMap(preds).run(); |
---|
| 1090 | ///\endcode |
---|
| 1091 | ///\warning Don't forget to put the \ref BfsWizard::run() "run()" |
---|
| 1092 | ///to the end of the parameter list. |
---|
| 1093 | ///\sa BfsWizard |
---|
| 1094 | ///\sa Bfs |
---|
| 1095 | template<class GR> |
---|
| 1096 | BfsWizard<BfsWizardBase<GR> > |
---|
| 1097 | bfs(const GR &g,typename GR::Node s=INVALID) |
---|
| 1098 | { |
---|
| 1099 | return BfsWizard<BfsWizardBase<GR> >(g,s); |
---|
| 1100 | } |
---|
| 1101 | |
---|
| 1102 | #ifdef DOXYGEN |
---|
| 1103 | /// \brief Visitor class for bfs. |
---|
[209] | 1104 | /// |
---|
[100] | 1105 | /// This class defines the interface of the BfsVisit events, and |
---|
| 1106 | /// it could be the base of a real Visitor class. |
---|
| 1107 | template <typename _Digraph> |
---|
| 1108 | struct BfsVisitor { |
---|
| 1109 | typedef _Digraph Digraph; |
---|
| 1110 | typedef typename Digraph::Arc Arc; |
---|
| 1111 | typedef typename Digraph::Node Node; |
---|
| 1112 | /// \brief Called when the arc reach a node. |
---|
[209] | 1113 | /// |
---|
[100] | 1114 | /// It is called when the bfs find an arc which target is not |
---|
| 1115 | /// reached yet. |
---|
| 1116 | void discover(const Arc& arc) {} |
---|
| 1117 | /// \brief Called when the node reached first time. |
---|
[209] | 1118 | /// |
---|
[100] | 1119 | /// It is Called when the node reached first time. |
---|
| 1120 | void reach(const Node& node) {} |
---|
[209] | 1121 | /// \brief Called when the arc examined but target of the arc |
---|
[100] | 1122 | /// already discovered. |
---|
[209] | 1123 | /// |
---|
| 1124 | /// It called when the arc examined but the target of the arc |
---|
[100] | 1125 | /// already discovered. |
---|
| 1126 | void examine(const Arc& arc) {} |
---|
| 1127 | /// \brief Called for the source node of the bfs. |
---|
[209] | 1128 | /// |
---|
[100] | 1129 | /// It is called for the source node of the bfs. |
---|
| 1130 | void start(const Node& node) {} |
---|
| 1131 | /// \brief Called when the node processed. |
---|
[209] | 1132 | /// |
---|
[100] | 1133 | /// It is Called when the node processed. |
---|
| 1134 | void process(const Node& node) {} |
---|
| 1135 | }; |
---|
| 1136 | #else |
---|
| 1137 | template <typename _Digraph> |
---|
| 1138 | struct BfsVisitor { |
---|
| 1139 | typedef _Digraph Digraph; |
---|
| 1140 | typedef typename Digraph::Arc Arc; |
---|
| 1141 | typedef typename Digraph::Node Node; |
---|
| 1142 | void discover(const Arc&) {} |
---|
| 1143 | void reach(const Node&) {} |
---|
| 1144 | void examine(const Arc&) {} |
---|
| 1145 | void start(const Node&) {} |
---|
| 1146 | void process(const Node&) {} |
---|
| 1147 | |
---|
| 1148 | template <typename _Visitor> |
---|
| 1149 | struct Constraints { |
---|
| 1150 | void constraints() { |
---|
[209] | 1151 | Arc arc; |
---|
| 1152 | Node node; |
---|
| 1153 | visitor.discover(arc); |
---|
| 1154 | visitor.reach(node); |
---|
| 1155 | visitor.examine(arc); |
---|
| 1156 | visitor.start(node); |
---|
[100] | 1157 | visitor.process(node); |
---|
| 1158 | } |
---|
| 1159 | _Visitor& visitor; |
---|
| 1160 | }; |
---|
| 1161 | }; |
---|
| 1162 | #endif |
---|
| 1163 | |
---|
| 1164 | /// \brief Default traits class of BfsVisit class. |
---|
| 1165 | /// |
---|
| 1166 | /// Default traits class of BfsVisit class. |
---|
[157] | 1167 | /// \tparam _Digraph Digraph type. |
---|
[100] | 1168 | template<class _Digraph> |
---|
| 1169 | struct BfsVisitDefaultTraits { |
---|
| 1170 | |
---|
[209] | 1171 | /// \brief The digraph type the algorithm runs on. |
---|
[100] | 1172 | typedef _Digraph Digraph; |
---|
| 1173 | |
---|
| 1174 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1175 | /// |
---|
[100] | 1176 | /// The type of the map that indicates which nodes are reached. |
---|
| 1177 | /// It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 1178 | /// \todo named parameter to set this type, function to read and write. |
---|
| 1179 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1180 | |
---|
| 1181 | /// \brief Instantiates a ReachedMap. |
---|
| 1182 | /// |
---|
[209] | 1183 | /// This function instantiates a \ref ReachedMap. |
---|
[100] | 1184 | /// \param digraph is the digraph, to which |
---|
| 1185 | /// we would like to define the \ref ReachedMap. |
---|
| 1186 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1187 | return new ReachedMap(digraph); |
---|
| 1188 | } |
---|
| 1189 | |
---|
| 1190 | }; |
---|
| 1191 | |
---|
| 1192 | /// \ingroup search |
---|
[209] | 1193 | /// |
---|
[100] | 1194 | /// \brief %BFS Visit algorithm class. |
---|
[209] | 1195 | /// |
---|
[100] | 1196 | /// This class provides an efficient implementation of the %BFS algorithm |
---|
| 1197 | /// with visitor interface. |
---|
| 1198 | /// |
---|
| 1199 | /// The %BfsVisit class provides an alternative interface to the Bfs |
---|
| 1200 | /// class. It works with callback mechanism, the BfsVisit object calls |
---|
[209] | 1201 | /// on every bfs event the \c Visitor class member functions. |
---|
[100] | 1202 | /// |
---|
[210] | 1203 | /// \tparam _Digraph The digraph type the algorithm runs on. |
---|
| 1204 | /// The default value is |
---|
[100] | 1205 | /// \ref ListDigraph. The value of _Digraph is not used directly by Bfs, it |
---|
| 1206 | /// is only passed to \ref BfsDefaultTraits. |
---|
[209] | 1207 | /// \tparam _Visitor The Visitor object for the algorithm. The |
---|
[100] | 1208 | /// \ref BfsVisitor "BfsVisitor<_Digraph>" is an empty Visitor which |
---|
| 1209 | /// does not observe the Bfs events. If you want to observe the bfs |
---|
| 1210 | /// events you should implement your own Visitor class. |
---|
[209] | 1211 | /// \tparam _Traits Traits class to set various data types used by the |
---|
[100] | 1212 | /// algorithm. The default traits class is |
---|
| 1213 | /// \ref BfsVisitDefaultTraits "BfsVisitDefaultTraits<_Digraph>". |
---|
| 1214 | /// See \ref BfsVisitDefaultTraits for the documentation of |
---|
| 1215 | /// a Bfs visit traits class. |
---|
| 1216 | #ifdef DOXYGEN |
---|
| 1217 | template <typename _Digraph, typename _Visitor, typename _Traits> |
---|
| 1218 | #else |
---|
| 1219 | template <typename _Digraph = ListDigraph, |
---|
[209] | 1220 | typename _Visitor = BfsVisitor<_Digraph>, |
---|
| 1221 | typename _Traits = BfsDefaultTraits<_Digraph> > |
---|
[100] | 1222 | #endif |
---|
| 1223 | class BfsVisit { |
---|
| 1224 | public: |
---|
[209] | 1225 | |
---|
[100] | 1226 | /// \brief \ref Exception for uninitialized parameters. |
---|
| 1227 | /// |
---|
| 1228 | /// This error represents problems in the initialization |
---|
| 1229 | /// of the parameters of the algorithms. |
---|
| 1230 | class UninitializedParameter : public lemon::UninitializedParameter { |
---|
| 1231 | public: |
---|
[209] | 1232 | virtual const char* what() const throw() |
---|
[100] | 1233 | { |
---|
[209] | 1234 | return "lemon::BfsVisit::UninitializedParameter"; |
---|
[100] | 1235 | } |
---|
| 1236 | }; |
---|
| 1237 | |
---|
| 1238 | typedef _Traits Traits; |
---|
| 1239 | |
---|
| 1240 | typedef typename Traits::Digraph Digraph; |
---|
| 1241 | |
---|
| 1242 | typedef _Visitor Visitor; |
---|
| 1243 | |
---|
| 1244 | ///The type of the map indicating which nodes are reached. |
---|
| 1245 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1246 | |
---|
| 1247 | private: |
---|
| 1248 | |
---|
| 1249 | typedef typename Digraph::Node Node; |
---|
| 1250 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1251 | typedef typename Digraph::Arc Arc; |
---|
| 1252 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1253 | |
---|
| 1254 | /// Pointer to the underlying digraph. |
---|
| 1255 | const Digraph *_digraph; |
---|
| 1256 | /// Pointer to the visitor object. |
---|
| 1257 | Visitor *_visitor; |
---|
| 1258 | ///Pointer to the map of reached status of the nodes. |
---|
| 1259 | ReachedMap *_reached; |
---|
| 1260 | ///Indicates if \ref _reached is locally allocated (\c true) or not. |
---|
| 1261 | bool local_reached; |
---|
| 1262 | |
---|
| 1263 | std::vector<typename Digraph::Node> _list; |
---|
| 1264 | int _list_front, _list_back; |
---|
| 1265 | |
---|
| 1266 | /// \brief Creates the maps if necessary. |
---|
| 1267 | /// |
---|
| 1268 | /// Creates the maps if necessary. |
---|
| 1269 | void create_maps() { |
---|
| 1270 | if(!_reached) { |
---|
[209] | 1271 | local_reached = true; |
---|
| 1272 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1273 | } |
---|
| 1274 | } |
---|
| 1275 | |
---|
| 1276 | protected: |
---|
| 1277 | |
---|
| 1278 | BfsVisit() {} |
---|
[209] | 1279 | |
---|
[100] | 1280 | public: |
---|
| 1281 | |
---|
| 1282 | typedef BfsVisit Create; |
---|
| 1283 | |
---|
| 1284 | /// \name Named template parameters |
---|
| 1285 | |
---|
| 1286 | ///@{ |
---|
| 1287 | template <class T> |
---|
| 1288 | struct DefReachedMapTraits : public Traits { |
---|
| 1289 | typedef T ReachedMap; |
---|
| 1290 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
[209] | 1291 | throw UninitializedParameter(); |
---|
[100] | 1292 | } |
---|
| 1293 | }; |
---|
[209] | 1294 | /// \brief \ref named-templ-param "Named parameter" for setting |
---|
[100] | 1295 | /// ReachedMap type |
---|
| 1296 | /// |
---|
| 1297 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type |
---|
| 1298 | template <class T> |
---|
| 1299 | struct DefReachedMap : public BfsVisit< Digraph, Visitor, |
---|
[209] | 1300 | DefReachedMapTraits<T> > { |
---|
[100] | 1301 | typedef BfsVisit< Digraph, Visitor, DefReachedMapTraits<T> > Create; |
---|
| 1302 | }; |
---|
| 1303 | ///@} |
---|
| 1304 | |
---|
[209] | 1305 | public: |
---|
| 1306 | |
---|
[100] | 1307 | /// \brief Constructor. |
---|
| 1308 | /// |
---|
| 1309 | /// Constructor. |
---|
| 1310 | /// |
---|
| 1311 | /// \param digraph the digraph the algorithm will run on. |
---|
| 1312 | /// \param visitor The visitor of the algorithm. |
---|
| 1313 | /// |
---|
[209] | 1314 | BfsVisit(const Digraph& digraph, Visitor& visitor) |
---|
[100] | 1315 | : _digraph(&digraph), _visitor(&visitor), |
---|
[209] | 1316 | _reached(0), local_reached(false) {} |
---|
| 1317 | |
---|
[100] | 1318 | /// \brief Destructor. |
---|
| 1319 | /// |
---|
| 1320 | /// Destructor. |
---|
| 1321 | ~BfsVisit() { |
---|
| 1322 | if(local_reached) delete _reached; |
---|
| 1323 | } |
---|
| 1324 | |
---|
| 1325 | /// \brief Sets the map indicating if a node is reached. |
---|
| 1326 | /// |
---|
| 1327 | /// Sets the map indicating if a node is reached. |
---|
| 1328 | /// If you don't use this function before calling \ref run(), |
---|
| 1329 | /// it will allocate one. The destuctor deallocates this |
---|
| 1330 | /// automatically allocated map, of course. |
---|
| 1331 | /// \return <tt> (*this) </tt> |
---|
| 1332 | BfsVisit &reachedMap(ReachedMap &m) { |
---|
| 1333 | if(local_reached) { |
---|
[209] | 1334 | delete _reached; |
---|
| 1335 | local_reached = false; |
---|
[100] | 1336 | } |
---|
| 1337 | _reached = &m; |
---|
| 1338 | return *this; |
---|
| 1339 | } |
---|
| 1340 | |
---|
| 1341 | public: |
---|
| 1342 | /// \name Execution control |
---|
| 1343 | /// The simplest way to execute the algorithm is to use |
---|
| 1344 | /// one of the member functions called \c run(...). |
---|
| 1345 | /// \n |
---|
| 1346 | /// If you need more control on the execution, |
---|
| 1347 | /// first you must call \ref init(), then you can adda source node |
---|
| 1348 | /// with \ref addSource(). |
---|
| 1349 | /// Finally \ref start() will perform the actual path |
---|
| 1350 | /// computation. |
---|
| 1351 | |
---|
| 1352 | /// @{ |
---|
| 1353 | /// \brief Initializes the internal data structures. |
---|
| 1354 | /// |
---|
| 1355 | /// Initializes the internal data structures. |
---|
| 1356 | /// |
---|
| 1357 | void init() { |
---|
| 1358 | create_maps(); |
---|
| 1359 | _list.resize(countNodes(*_digraph)); |
---|
| 1360 | _list_front = _list_back = -1; |
---|
| 1361 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
---|
[209] | 1362 | _reached->set(u, false); |
---|
[100] | 1363 | } |
---|
| 1364 | } |
---|
[209] | 1365 | |
---|
[100] | 1366 | /// \brief Adds a new source node. |
---|
| 1367 | /// |
---|
| 1368 | /// Adds a new source node to the set of nodes to be processed. |
---|
| 1369 | void addSource(Node s) { |
---|
| 1370 | if(!(*_reached)[s]) { |
---|
[209] | 1371 | _reached->set(s,true); |
---|
| 1372 | _visitor->start(s); |
---|
| 1373 | _visitor->reach(s); |
---|
[100] | 1374 | _list[++_list_back] = s; |
---|
[209] | 1375 | } |
---|
[100] | 1376 | } |
---|
[209] | 1377 | |
---|
[100] | 1378 | /// \brief Processes the next node. |
---|
| 1379 | /// |
---|
| 1380 | /// Processes the next node. |
---|
| 1381 | /// |
---|
| 1382 | /// \return The processed node. |
---|
| 1383 | /// |
---|
| 1384 | /// \pre The queue must not be empty! |
---|
[209] | 1385 | Node processNextNode() { |
---|
[100] | 1386 | Node n = _list[++_list_front]; |
---|
| 1387 | _visitor->process(n); |
---|
| 1388 | Arc e; |
---|
| 1389 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1390 | Node m = _digraph->target(e); |
---|
| 1391 | if (!(*_reached)[m]) { |
---|
| 1392 | _visitor->discover(e); |
---|
| 1393 | _visitor->reach(m); |
---|
| 1394 | _reached->set(m, true); |
---|
| 1395 | _list[++_list_back] = m; |
---|
| 1396 | } else { |
---|
| 1397 | _visitor->examine(e); |
---|
| 1398 | } |
---|
| 1399 | } |
---|
| 1400 | return n; |
---|
| 1401 | } |
---|
| 1402 | |
---|
| 1403 | /// \brief Processes the next node. |
---|
| 1404 | /// |
---|
| 1405 | /// Processes the next node. And checks that the given target node |
---|
| 1406 | /// is reached. If the target node is reachable from the processed |
---|
| 1407 | /// node then the reached parameter will be set true. The reached |
---|
| 1408 | /// parameter should be initially false. |
---|
| 1409 | /// |
---|
| 1410 | /// \param target The target node. |
---|
| 1411 | /// \retval reach Indicates that the target node is reached. |
---|
| 1412 | /// \return The processed node. |
---|
| 1413 | /// |
---|
| 1414 | /// \warning The queue must not be empty! |
---|
| 1415 | Node processNextNode(Node target, bool& reach) { |
---|
| 1416 | Node n = _list[++_list_front]; |
---|
| 1417 | _visitor->process(n); |
---|
| 1418 | Arc e; |
---|
| 1419 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1420 | Node m = _digraph->target(e); |
---|
| 1421 | if (!(*_reached)[m]) { |
---|
| 1422 | _visitor->discover(e); |
---|
| 1423 | _visitor->reach(m); |
---|
| 1424 | _reached->set(m, true); |
---|
| 1425 | _list[++_list_back] = m; |
---|
| 1426 | reach = reach || (target == m); |
---|
| 1427 | } else { |
---|
| 1428 | _visitor->examine(e); |
---|
| 1429 | } |
---|
| 1430 | } |
---|
| 1431 | return n; |
---|
| 1432 | } |
---|
| 1433 | |
---|
| 1434 | /// \brief Processes the next node. |
---|
| 1435 | /// |
---|
| 1436 | /// Processes the next node. And checks that at least one of |
---|
| 1437 | /// reached node has true value in the \c nm node map. If one node |
---|
| 1438 | /// with true value is reachable from the processed node then the |
---|
| 1439 | /// rnode parameter will be set to the first of such nodes. |
---|
| 1440 | /// |
---|
| 1441 | /// \param nm The node map of possible targets. |
---|
| 1442 | /// \retval rnode The reached target node. |
---|
| 1443 | /// \return The processed node. |
---|
| 1444 | /// |
---|
| 1445 | /// \warning The queue must not be empty! |
---|
| 1446 | template <typename NM> |
---|
| 1447 | Node processNextNode(const NM& nm, Node& rnode) { |
---|
| 1448 | Node n = _list[++_list_front]; |
---|
| 1449 | _visitor->process(n); |
---|
| 1450 | Arc e; |
---|
| 1451 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1452 | Node m = _digraph->target(e); |
---|
| 1453 | if (!(*_reached)[m]) { |
---|
| 1454 | _visitor->discover(e); |
---|
| 1455 | _visitor->reach(m); |
---|
| 1456 | _reached->set(m, true); |
---|
| 1457 | _list[++_list_back] = m; |
---|
| 1458 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 1459 | } else { |
---|
| 1460 | _visitor->examine(e); |
---|
| 1461 | } |
---|
| 1462 | } |
---|
| 1463 | return n; |
---|
| 1464 | } |
---|
| 1465 | |
---|
| 1466 | /// \brief Next node to be processed. |
---|
| 1467 | /// |
---|
| 1468 | /// Next node to be processed. |
---|
| 1469 | /// |
---|
| 1470 | /// \return The next node to be processed or INVALID if the stack is |
---|
| 1471 | /// empty. |
---|
[209] | 1472 | Node nextNode() { |
---|
[100] | 1473 | return _list_front != _list_back ? _list[_list_front + 1] : INVALID; |
---|
| 1474 | } |
---|
| 1475 | |
---|
| 1476 | /// \brief Returns \c false if there are nodes |
---|
| 1477 | /// to be processed in the queue |
---|
| 1478 | /// |
---|
| 1479 | /// Returns \c false if there are nodes |
---|
| 1480 | /// to be processed in the queue |
---|
| 1481 | bool emptyQueue() { return _list_front == _list_back; } |
---|
| 1482 | |
---|
| 1483 | /// \brief Returns the number of the nodes to be processed. |
---|
| 1484 | /// |
---|
| 1485 | /// Returns the number of the nodes to be processed in the queue. |
---|
| 1486 | int queueSize() { return _list_back - _list_front; } |
---|
[209] | 1487 | |
---|
[100] | 1488 | /// \brief Executes the algorithm. |
---|
| 1489 | /// |
---|
| 1490 | /// Executes the algorithm. |
---|
| 1491 | /// |
---|
| 1492 | /// \pre init() must be called and at least one node should be added |
---|
| 1493 | /// with addSource() before using this function. |
---|
| 1494 | void start() { |
---|
| 1495 | while ( !emptyQueue() ) processNextNode(); |
---|
| 1496 | } |
---|
[209] | 1497 | |
---|
[100] | 1498 | /// \brief Executes the algorithm until \c dest is reached. |
---|
| 1499 | /// |
---|
| 1500 | /// Executes the algorithm until \c dest is reached. |
---|
| 1501 | /// |
---|
| 1502 | /// \pre init() must be called and at least one node should be added |
---|
| 1503 | /// with addSource() before using this function. |
---|
| 1504 | void start(Node dest) { |
---|
| 1505 | bool reach = false; |
---|
| 1506 | while ( !emptyQueue() && !reach ) processNextNode(dest, reach); |
---|
| 1507 | } |
---|
[209] | 1508 | |
---|
[100] | 1509 | /// \brief Executes the algorithm until a condition is met. |
---|
| 1510 | /// |
---|
| 1511 | /// Executes the algorithm until a condition is met. |
---|
| 1512 | /// |
---|
| 1513 | /// \pre init() must be called and at least one node should be added |
---|
| 1514 | /// with addSource() before using this function. |
---|
| 1515 | /// |
---|
| 1516 | ///\param nm must be a bool (or convertible) node map. The |
---|
| 1517 | ///algorithm will stop when it reaches a node \c v with |
---|
| 1518 | /// <tt>nm[v]</tt> true. |
---|
| 1519 | /// |
---|
| 1520 | ///\return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 1521 | ///\c INVALID if no such node was found. |
---|
| 1522 | template <typename NM> |
---|
| 1523 | Node start(const NM &nm) { |
---|
| 1524 | Node rnode = INVALID; |
---|
| 1525 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 1526 | processNextNode(nm, rnode); |
---|
[100] | 1527 | } |
---|
| 1528 | return rnode; |
---|
| 1529 | } |
---|
| 1530 | |
---|
| 1531 | /// \brief Runs %BFSVisit algorithm from node \c s. |
---|
| 1532 | /// |
---|
| 1533 | /// This method runs the %BFS algorithm from a root node \c s. |
---|
| 1534 | /// \note b.run(s) is just a shortcut of the following code. |
---|
| 1535 | ///\code |
---|
| 1536 | /// b.init(); |
---|
| 1537 | /// b.addSource(s); |
---|
| 1538 | /// b.start(); |
---|
| 1539 | ///\endcode |
---|
| 1540 | void run(Node s) { |
---|
| 1541 | init(); |
---|
| 1542 | addSource(s); |
---|
| 1543 | start(); |
---|
| 1544 | } |
---|
| 1545 | |
---|
| 1546 | /// \brief Runs %BFSVisit algorithm to visit all nodes in the digraph. |
---|
[209] | 1547 | /// |
---|
[100] | 1548 | /// This method runs the %BFS algorithm in order to |
---|
| 1549 | /// compute the %BFS path to each node. The algorithm computes |
---|
| 1550 | /// - The %BFS tree. |
---|
| 1551 | /// - The distance of each node from the root in the %BFS tree. |
---|
| 1552 | /// |
---|
| 1553 | ///\note b.run() is just a shortcut of the following code. |
---|
| 1554 | ///\code |
---|
| 1555 | /// b.init(); |
---|
| 1556 | /// for (NodeIt it(digraph); it != INVALID; ++it) { |
---|
| 1557 | /// if (!b.reached(it)) { |
---|
| 1558 | /// b.addSource(it); |
---|
| 1559 | /// b.start(); |
---|
| 1560 | /// } |
---|
| 1561 | /// } |
---|
| 1562 | ///\endcode |
---|
| 1563 | void run() { |
---|
| 1564 | init(); |
---|
| 1565 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
| 1566 | if (!reached(it)) { |
---|
| 1567 | addSource(it); |
---|
| 1568 | start(); |
---|
| 1569 | } |
---|
| 1570 | } |
---|
| 1571 | } |
---|
| 1572 | ///@} |
---|
| 1573 | |
---|
| 1574 | /// \name Query Functions |
---|
| 1575 | /// The result of the %BFS algorithm can be obtained using these |
---|
| 1576 | /// functions.\n |
---|
| 1577 | /// Before the use of these functions, |
---|
| 1578 | /// either run() or start() must be called. |
---|
| 1579 | ///@{ |
---|
| 1580 | |
---|
| 1581 | /// \brief Checks if a node is reachable from the root. |
---|
| 1582 | /// |
---|
| 1583 | /// Returns \c true if \c v is reachable from the root(s). |
---|
| 1584 | /// \warning The source nodes are inditated as unreachable. |
---|
| 1585 | /// \pre Either \ref run() or \ref start() |
---|
| 1586 | /// must be called before using this function. |
---|
| 1587 | /// |
---|
| 1588 | bool reached(Node v) { return (*_reached)[v]; } |
---|
| 1589 | ///@} |
---|
| 1590 | }; |
---|
| 1591 | |
---|
| 1592 | } //END OF NAMESPACE LEMON |
---|
| 1593 | |
---|
| 1594 | #endif |
---|
| 1595 | |
---|