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