[209] | 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
---|
[100] | 2 | * |
---|
[209] | 3 | * This file is a part of LEMON, a generic C++ optimization library. |
---|
[100] | 4 | * |
---|
| 5 | * Copyright (C) 2003-2008 |
---|
| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
---|
| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
---|
| 8 | * |
---|
| 9 | * Permission to use, modify and distribute this software is granted |
---|
| 10 | * provided that this copyright notice appears in all copies. For |
---|
| 11 | * precise terms see the accompanying LICENSE file. |
---|
| 12 | * |
---|
| 13 | * This software is provided "AS IS" with no warranty of any kind, |
---|
| 14 | * express or implied, and with no claim as to its suitability for any |
---|
| 15 | * purpose. |
---|
| 16 | * |
---|
| 17 | */ |
---|
| 18 | |
---|
| 19 | #ifndef LEMON_BFS_H |
---|
| 20 | #define LEMON_BFS_H |
---|
| 21 | |
---|
| 22 | ///\ingroup search |
---|
| 23 | ///\file |
---|
[244] | 24 | ///\brief BFS algorithm. |
---|
[100] | 25 | |
---|
| 26 | #include <lemon/list_graph.h> |
---|
| 27 | #include <lemon/bits/path_dump.h> |
---|
[220] | 28 | #include <lemon/core.h> |
---|
[100] | 29 | #include <lemon/error.h> |
---|
| 30 | #include <lemon/maps.h> |
---|
| 31 | |
---|
| 32 | namespace lemon { |
---|
| 33 | |
---|
| 34 | ///Default traits class of Bfs class. |
---|
| 35 | |
---|
| 36 | ///Default traits class of Bfs class. |
---|
[157] | 37 | ///\tparam GR Digraph type. |
---|
[100] | 38 | template<class GR> |
---|
| 39 | struct BfsDefaultTraits |
---|
| 40 | { |
---|
[244] | 41 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 42 | typedef GR Digraph; |
---|
[244] | 43 | |
---|
| 44 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 45 | ///arcs of the shortest paths. |
---|
[209] | 46 | /// |
---|
[244] | 47 | ///The type of the map that stores the predecessor |
---|
[100] | 48 | ///arcs of the shortest paths. |
---|
| 49 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[244] | 50 | typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap; |
---|
| 51 | ///Instantiates a \ref PredMap. |
---|
[209] | 52 | |
---|
| 53 | ///This function instantiates a \ref PredMap. |
---|
[244] | 54 | ///\param g is the digraph, to which we would like to define the |
---|
| 55 | ///\ref PredMap. |
---|
[100] | 56 | ///\todo The digraph alone may be insufficient to initialize |
---|
[244] | 57 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 58 | { |
---|
[244] | 59 | return new PredMap(g); |
---|
[100] | 60 | } |
---|
[244] | 61 | |
---|
[100] | 62 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 63 | |
---|
[100] | 64 | ///The type of the map that indicates which nodes are processed. |
---|
| 65 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[244] | 66 | ///By default it is a NullMap. |
---|
[100] | 67 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[244] | 68 | ///Instantiates a \ref ProcessedMap. |
---|
[209] | 69 | |
---|
| 70 | ///This function instantiates a \ref ProcessedMap. |
---|
[100] | 71 | ///\param g is the digraph, to which |
---|
| 72 | ///we would like to define the \ref ProcessedMap |
---|
| 73 | #ifdef DOXYGEN |
---|
[244] | 74 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 75 | #else |
---|
[244] | 76 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 77 | #endif |
---|
| 78 | { |
---|
| 79 | return new ProcessedMap(); |
---|
| 80 | } |
---|
[244] | 81 | |
---|
[100] | 82 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 83 | |
---|
[100] | 84 | ///The type of the map that indicates which nodes are reached. |
---|
[244] | 85 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 86 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[244] | 87 | ///Instantiates a \ref ReachedMap. |
---|
[209] | 88 | |
---|
| 89 | ///This function instantiates a \ref ReachedMap. |
---|
[244] | 90 | ///\param g is the digraph, to which |
---|
[100] | 91 | ///we would like to define the \ref ReachedMap. |
---|
[244] | 92 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 93 | { |
---|
[244] | 94 | return new ReachedMap(g); |
---|
[100] | 95 | } |
---|
[209] | 96 | |
---|
[244] | 97 | ///The type of the map that stores the distances of the nodes. |
---|
| 98 | |
---|
| 99 | ///The type of the map that stores the distances of the nodes. |
---|
[100] | 100 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 101 | typedef typename Digraph::template NodeMap<int> DistMap; |
---|
[244] | 102 | ///Instantiates a \ref DistMap. |
---|
[209] | 103 | |
---|
| 104 | ///This function instantiates a \ref DistMap. |
---|
[244] | 105 | ///\param g is the digraph, to which we would like to define the |
---|
| 106 | ///\ref DistMap. |
---|
| 107 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 108 | { |
---|
[244] | 109 | return new DistMap(g); |
---|
[100] | 110 | } |
---|
| 111 | }; |
---|
[209] | 112 | |
---|
[100] | 113 | ///%BFS algorithm class. |
---|
[209] | 114 | |
---|
[100] | 115 | ///\ingroup search |
---|
| 116 | ///This class provides an efficient implementation of the %BFS algorithm. |
---|
| 117 | /// |
---|
[244] | 118 | ///There is also a \ref bfs() "function type interface" for the BFS |
---|
| 119 | ///algorithm, which is convenient in the simplier cases and it can be |
---|
| 120 | ///used easier. |
---|
| 121 | /// |
---|
| 122 | ///\tparam GR The type of the digraph the algorithm runs on. |
---|
| 123 | ///The default value is \ref ListDigraph. The value of GR is not used |
---|
| 124 | ///directly by \ref Bfs, it is only passed to \ref BfsDefaultTraits. |
---|
[157] | 125 | ///\tparam TR Traits class to set various data types used by the algorithm. |
---|
[100] | 126 | ///The default traits class is |
---|
| 127 | ///\ref BfsDefaultTraits "BfsDefaultTraits<GR>". |
---|
| 128 | ///See \ref BfsDefaultTraits for the documentation of |
---|
| 129 | ///a Bfs traits class. |
---|
| 130 | #ifdef DOXYGEN |
---|
| 131 | template <typename GR, |
---|
[209] | 132 | typename TR> |
---|
[100] | 133 | #else |
---|
| 134 | template <typename GR=ListDigraph, |
---|
[209] | 135 | typename TR=BfsDefaultTraits<GR> > |
---|
[100] | 136 | #endif |
---|
| 137 | class Bfs { |
---|
| 138 | public: |
---|
[244] | 139 | ///\ref Exception for uninitialized parameters. |
---|
| 140 | |
---|
| 141 | ///This error represents problems in the initialization of the |
---|
| 142 | ///parameters of the algorithm. |
---|
[100] | 143 | class UninitializedParameter : public lemon::UninitializedParameter { |
---|
| 144 | public: |
---|
| 145 | virtual const char* what() const throw() { |
---|
[209] | 146 | return "lemon::Bfs::UninitializedParameter"; |
---|
[100] | 147 | } |
---|
| 148 | }; |
---|
| 149 | |
---|
[244] | 150 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 151 | typedef typename TR::Digraph Digraph; |
---|
[209] | 152 | |
---|
[244] | 153 | ///\brief The type of the map that stores the predecessor arcs of the |
---|
| 154 | ///shortest paths. |
---|
[100] | 155 | typedef typename TR::PredMap PredMap; |
---|
[244] | 156 | ///The type of the map that stores the distances of the nodes. |
---|
| 157 | typedef typename TR::DistMap DistMap; |
---|
| 158 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 159 | typedef typename TR::ReachedMap ReachedMap; |
---|
[244] | 160 | ///The type of the map that indicates which nodes are processed. |
---|
[100] | 161 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
[244] | 162 | ///The type of the paths. |
---|
| 163 | typedef PredMapPath<Digraph, PredMap> Path; |
---|
| 164 | |
---|
| 165 | ///The traits class. |
---|
| 166 | typedef TR Traits; |
---|
| 167 | |
---|
[100] | 168 | private: |
---|
| 169 | |
---|
| 170 | typedef typename Digraph::Node Node; |
---|
| 171 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 172 | typedef typename Digraph::Arc Arc; |
---|
| 173 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 174 | |
---|
[244] | 175 | //Pointer to the underlying digraph. |
---|
[100] | 176 | const Digraph *G; |
---|
[244] | 177 | //Pointer to the map of predecessor arcs. |
---|
[100] | 178 | PredMap *_pred; |
---|
[244] | 179 | //Indicates if _pred is locally allocated (true) or not. |
---|
[100] | 180 | bool local_pred; |
---|
[244] | 181 | //Pointer to the map of distances. |
---|
[100] | 182 | DistMap *_dist; |
---|
[244] | 183 | //Indicates if _dist is locally allocated (true) or not. |
---|
[100] | 184 | bool local_dist; |
---|
[244] | 185 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 186 | ReachedMap *_reached; |
---|
[244] | 187 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 188 | bool local_reached; |
---|
[244] | 189 | //Pointer to the map of processed status of the nodes. |
---|
[100] | 190 | ProcessedMap *_processed; |
---|
[244] | 191 | //Indicates if _processed is locally allocated (true) or not. |
---|
[100] | 192 | bool local_processed; |
---|
| 193 | |
---|
| 194 | std::vector<typename Digraph::Node> _queue; |
---|
| 195 | int _queue_head,_queue_tail,_queue_next_dist; |
---|
| 196 | int _curr_dist; |
---|
| 197 | |
---|
| 198 | ///Creates the maps if necessary. |
---|
| 199 | ///\todo Better memory allocation (instead of new). |
---|
[209] | 200 | void create_maps() |
---|
[100] | 201 | { |
---|
| 202 | if(!_pred) { |
---|
[209] | 203 | local_pred = true; |
---|
| 204 | _pred = Traits::createPredMap(*G); |
---|
[100] | 205 | } |
---|
| 206 | if(!_dist) { |
---|
[209] | 207 | local_dist = true; |
---|
| 208 | _dist = Traits::createDistMap(*G); |
---|
[100] | 209 | } |
---|
| 210 | if(!_reached) { |
---|
[209] | 211 | local_reached = true; |
---|
| 212 | _reached = Traits::createReachedMap(*G); |
---|
[100] | 213 | } |
---|
| 214 | if(!_processed) { |
---|
[209] | 215 | local_processed = true; |
---|
| 216 | _processed = Traits::createProcessedMap(*G); |
---|
[100] | 217 | } |
---|
| 218 | } |
---|
| 219 | |
---|
| 220 | protected: |
---|
[209] | 221 | |
---|
[100] | 222 | Bfs() {} |
---|
[209] | 223 | |
---|
[100] | 224 | public: |
---|
[209] | 225 | |
---|
[100] | 226 | typedef Bfs Create; |
---|
| 227 | |
---|
| 228 | ///\name Named template parameters |
---|
| 229 | |
---|
| 230 | ///@{ |
---|
| 231 | |
---|
| 232 | template <class T> |
---|
[257] | 233 | struct SetPredMapTraits : public Traits { |
---|
[100] | 234 | typedef T PredMap; |
---|
[209] | 235 | static PredMap *createPredMap(const Digraph &) |
---|
[100] | 236 | { |
---|
[209] | 237 | throw UninitializedParameter(); |
---|
[100] | 238 | } |
---|
| 239 | }; |
---|
| 240 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 241 | ///\ref PredMap type. |
---|
[100] | 242 | /// |
---|
[244] | 243 | ///\ref named-templ-param "Named parameter" for setting |
---|
| 244 | ///\ref PredMap type. |
---|
[100] | 245 | template <class T> |
---|
[257] | 246 | struct SetPredMap : public Bfs< Digraph, SetPredMapTraits<T> > { |
---|
| 247 | typedef Bfs< Digraph, SetPredMapTraits<T> > Create; |
---|
[100] | 248 | }; |
---|
[209] | 249 | |
---|
[100] | 250 | template <class T> |
---|
[257] | 251 | struct SetDistMapTraits : public Traits { |
---|
[100] | 252 | typedef T DistMap; |
---|
[209] | 253 | static DistMap *createDistMap(const Digraph &) |
---|
[100] | 254 | { |
---|
[209] | 255 | throw UninitializedParameter(); |
---|
[100] | 256 | } |
---|
| 257 | }; |
---|
| 258 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 259 | ///\ref DistMap type. |
---|
[100] | 260 | /// |
---|
[244] | 261 | ///\ref named-templ-param "Named parameter" for setting |
---|
| 262 | ///\ref DistMap type. |
---|
[100] | 263 | template <class T> |
---|
[257] | 264 | struct SetDistMap : public Bfs< Digraph, SetDistMapTraits<T> > { |
---|
| 265 | typedef Bfs< Digraph, SetDistMapTraits<T> > Create; |
---|
[100] | 266 | }; |
---|
[209] | 267 | |
---|
[100] | 268 | template <class T> |
---|
[257] | 269 | struct SetReachedMapTraits : public Traits { |
---|
[100] | 270 | typedef T ReachedMap; |
---|
[209] | 271 | static ReachedMap *createReachedMap(const Digraph &) |
---|
[100] | 272 | { |
---|
[209] | 273 | throw UninitializedParameter(); |
---|
[100] | 274 | } |
---|
| 275 | }; |
---|
| 276 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 277 | ///\ref ReachedMap type. |
---|
[100] | 278 | /// |
---|
[244] | 279 | ///\ref named-templ-param "Named parameter" for setting |
---|
| 280 | ///\ref ReachedMap type. |
---|
[100] | 281 | template <class T> |
---|
[257] | 282 | struct SetReachedMap : public Bfs< Digraph, SetReachedMapTraits<T> > { |
---|
| 283 | typedef Bfs< Digraph, SetReachedMapTraits<T> > Create; |
---|
[100] | 284 | }; |
---|
[209] | 285 | |
---|
[100] | 286 | template <class T> |
---|
[257] | 287 | struct SetProcessedMapTraits : public Traits { |
---|
[100] | 288 | typedef T ProcessedMap; |
---|
[209] | 289 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 290 | { |
---|
[209] | 291 | throw UninitializedParameter(); |
---|
[100] | 292 | } |
---|
| 293 | }; |
---|
| 294 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 295 | ///\ref ProcessedMap type. |
---|
[100] | 296 | /// |
---|
[244] | 297 | ///\ref named-templ-param "Named parameter" for setting |
---|
| 298 | ///\ref ProcessedMap type. |
---|
[100] | 299 | template <class T> |
---|
[257] | 300 | struct SetProcessedMap : public Bfs< Digraph, SetProcessedMapTraits<T> > { |
---|
| 301 | typedef Bfs< Digraph, SetProcessedMapTraits<T> > Create; |
---|
[100] | 302 | }; |
---|
[209] | 303 | |
---|
[257] | 304 | struct SetStandardProcessedMapTraits : public Traits { |
---|
[100] | 305 | typedef typename Digraph::template NodeMap<bool> ProcessedMap; |
---|
[244] | 306 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 307 | { |
---|
[244] | 308 | return new ProcessedMap(g); |
---|
[100] | 309 | } |
---|
| 310 | }; |
---|
[244] | 311 | ///\brief \ref named-templ-param "Named parameter" for setting |
---|
| 312 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
---|
[100] | 313 | /// |
---|
[244] | 314 | ///\ref named-templ-param "Named parameter" for setting |
---|
| 315 | ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>. |
---|
[100] | 316 | ///If you don't set it explicitly, it will be automatically allocated. |
---|
[257] | 317 | struct SetStandardProcessedMap : |
---|
| 318 | public Bfs< Digraph, SetStandardProcessedMapTraits > { |
---|
| 319 | typedef Bfs< Digraph, SetStandardProcessedMapTraits > Create; |
---|
[100] | 320 | }; |
---|
[209] | 321 | |
---|
[100] | 322 | ///@} |
---|
| 323 | |
---|
[209] | 324 | public: |
---|
| 325 | |
---|
[100] | 326 | ///Constructor. |
---|
[209] | 327 | |
---|
[244] | 328 | ///Constructor. |
---|
| 329 | ///\param g The digraph the algorithm runs on. |
---|
| 330 | Bfs(const Digraph &g) : |
---|
| 331 | G(&g), |
---|
[100] | 332 | _pred(NULL), local_pred(false), |
---|
| 333 | _dist(NULL), local_dist(false), |
---|
| 334 | _reached(NULL), local_reached(false), |
---|
| 335 | _processed(NULL), local_processed(false) |
---|
| 336 | { } |
---|
[209] | 337 | |
---|
[100] | 338 | ///Destructor. |
---|
[209] | 339 | ~Bfs() |
---|
[100] | 340 | { |
---|
| 341 | if(local_pred) delete _pred; |
---|
| 342 | if(local_dist) delete _dist; |
---|
| 343 | if(local_reached) delete _reached; |
---|
| 344 | if(local_processed) delete _processed; |
---|
| 345 | } |
---|
| 346 | |
---|
[244] | 347 | ///Sets the map that stores the predecessor arcs. |
---|
[100] | 348 | |
---|
[244] | 349 | ///Sets the map that stores the predecessor arcs. |
---|
[100] | 350 | ///If you don't use this function before calling \ref run(), |
---|
| 351 | ///it will allocate one. The destructor deallocates this |
---|
| 352 | ///automatically allocated map, of course. |
---|
| 353 | ///\return <tt> (*this) </tt> |
---|
[209] | 354 | Bfs &predMap(PredMap &m) |
---|
[100] | 355 | { |
---|
| 356 | if(local_pred) { |
---|
[209] | 357 | delete _pred; |
---|
| 358 | local_pred=false; |
---|
[100] | 359 | } |
---|
| 360 | _pred = &m; |
---|
| 361 | return *this; |
---|
| 362 | } |
---|
| 363 | |
---|
[244] | 364 | ///Sets the map that indicates which nodes are reached. |
---|
[100] | 365 | |
---|
[244] | 366 | ///Sets the map that indicates which nodes are reached. |
---|
[100] | 367 | ///If you don't use this function before calling \ref run(), |
---|
| 368 | ///it will allocate one. The destructor deallocates this |
---|
| 369 | ///automatically allocated map, of course. |
---|
| 370 | ///\return <tt> (*this) </tt> |
---|
[209] | 371 | Bfs &reachedMap(ReachedMap &m) |
---|
[100] | 372 | { |
---|
| 373 | if(local_reached) { |
---|
[209] | 374 | delete _reached; |
---|
| 375 | local_reached=false; |
---|
[100] | 376 | } |
---|
| 377 | _reached = &m; |
---|
| 378 | return *this; |
---|
| 379 | } |
---|
| 380 | |
---|
[244] | 381 | ///Sets the map that indicates which nodes are processed. |
---|
[100] | 382 | |
---|
[244] | 383 | ///Sets the map that indicates which nodes are processed. |
---|
[100] | 384 | ///If you don't use this function before calling \ref run(), |
---|
| 385 | ///it will allocate one. The destructor deallocates this |
---|
| 386 | ///automatically allocated map, of course. |
---|
| 387 | ///\return <tt> (*this) </tt> |
---|
[209] | 388 | Bfs &processedMap(ProcessedMap &m) |
---|
[100] | 389 | { |
---|
| 390 | if(local_processed) { |
---|
[209] | 391 | delete _processed; |
---|
| 392 | local_processed=false; |
---|
[100] | 393 | } |
---|
| 394 | _processed = &m; |
---|
| 395 | return *this; |
---|
| 396 | } |
---|
| 397 | |
---|
[244] | 398 | ///Sets the map that stores the distances of the nodes. |
---|
[100] | 399 | |
---|
[244] | 400 | ///Sets the map that stores the distances of the nodes calculated by |
---|
| 401 | ///the algorithm. |
---|
[100] | 402 | ///If you don't use this function before calling \ref run(), |
---|
| 403 | ///it will allocate one. The destructor deallocates this |
---|
| 404 | ///automatically allocated map, of course. |
---|
| 405 | ///\return <tt> (*this) </tt> |
---|
[209] | 406 | Bfs &distMap(DistMap &m) |
---|
[100] | 407 | { |
---|
| 408 | if(local_dist) { |
---|
[209] | 409 | delete _dist; |
---|
| 410 | local_dist=false; |
---|
[100] | 411 | } |
---|
| 412 | _dist = &m; |
---|
| 413 | return *this; |
---|
| 414 | } |
---|
| 415 | |
---|
| 416 | public: |
---|
[244] | 417 | |
---|
[100] | 418 | ///\name Execution control |
---|
| 419 | ///The simplest way to execute the algorithm is to use |
---|
[244] | 420 | ///one of the member functions called \ref lemon::Bfs::run() "run()". |
---|
[100] | 421 | ///\n |
---|
[244] | 422 | ///If you need more control on the execution, first you must call |
---|
| 423 | ///\ref lemon::Bfs::init() "init()", then you can add several source |
---|
| 424 | ///nodes with \ref lemon::Bfs::addSource() "addSource()". |
---|
| 425 | ///Finally \ref lemon::Bfs::start() "start()" will perform the |
---|
| 426 | ///actual path computation. |
---|
[100] | 427 | |
---|
| 428 | ///@{ |
---|
| 429 | |
---|
[244] | 430 | ///Initializes the internal data structures. |
---|
| 431 | |
---|
[100] | 432 | ///Initializes the internal data structures. |
---|
| 433 | /// |
---|
| 434 | void init() |
---|
| 435 | { |
---|
| 436 | create_maps(); |
---|
| 437 | _queue.resize(countNodes(*G)); |
---|
| 438 | _queue_head=_queue_tail=0; |
---|
| 439 | _curr_dist=1; |
---|
| 440 | for ( NodeIt u(*G) ; u!=INVALID ; ++u ) { |
---|
[209] | 441 | _pred->set(u,INVALID); |
---|
| 442 | _reached->set(u,false); |
---|
| 443 | _processed->set(u,false); |
---|
[100] | 444 | } |
---|
| 445 | } |
---|
[209] | 446 | |
---|
[100] | 447 | ///Adds a new source node. |
---|
| 448 | |
---|
| 449 | ///Adds a new source node to the set of nodes to be processed. |
---|
| 450 | /// |
---|
| 451 | void addSource(Node s) |
---|
| 452 | { |
---|
| 453 | if(!(*_reached)[s]) |
---|
[209] | 454 | { |
---|
| 455 | _reached->set(s,true); |
---|
| 456 | _pred->set(s,INVALID); |
---|
| 457 | _dist->set(s,0); |
---|
| 458 | _queue[_queue_head++]=s; |
---|
| 459 | _queue_next_dist=_queue_head; |
---|
| 460 | } |
---|
[100] | 461 | } |
---|
[209] | 462 | |
---|
[100] | 463 | ///Processes the next node. |
---|
| 464 | |
---|
| 465 | ///Processes the next node. |
---|
| 466 | /// |
---|
| 467 | ///\return The processed node. |
---|
| 468 | /// |
---|
[244] | 469 | ///\pre The queue must not be empty. |
---|
[100] | 470 | Node processNextNode() |
---|
| 471 | { |
---|
| 472 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 473 | _curr_dist++; |
---|
| 474 | _queue_next_dist=_queue_head; |
---|
[100] | 475 | } |
---|
| 476 | Node n=_queue[_queue_tail++]; |
---|
| 477 | _processed->set(n,true); |
---|
| 478 | Node m; |
---|
| 479 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 480 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 481 | _queue[_queue_head++]=m; |
---|
| 482 | _reached->set(m,true); |
---|
| 483 | _pred->set(m,e); |
---|
| 484 | _dist->set(m,_curr_dist); |
---|
| 485 | } |
---|
[100] | 486 | return n; |
---|
| 487 | } |
---|
| 488 | |
---|
| 489 | ///Processes the next node. |
---|
| 490 | |
---|
[244] | 491 | ///Processes the next node and checks if the given target node |
---|
[100] | 492 | ///is reached. If the target node is reachable from the processed |
---|
[244] | 493 | ///node, then the \c reach parameter will be set to \c true. |
---|
[100] | 494 | /// |
---|
| 495 | ///\param target The target node. |
---|
[244] | 496 | ///\retval reach Indicates if the target node is reached. |
---|
| 497 | ///It should be initially \c false. |
---|
| 498 | /// |
---|
[100] | 499 | ///\return The processed node. |
---|
| 500 | /// |
---|
[244] | 501 | ///\pre The queue must not be empty. |
---|
[100] | 502 | Node processNextNode(Node target, bool& reach) |
---|
| 503 | { |
---|
| 504 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 505 | _curr_dist++; |
---|
| 506 | _queue_next_dist=_queue_head; |
---|
[100] | 507 | } |
---|
| 508 | Node n=_queue[_queue_tail++]; |
---|
| 509 | _processed->set(n,true); |
---|
| 510 | Node m; |
---|
| 511 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 512 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 513 | _queue[_queue_head++]=m; |
---|
| 514 | _reached->set(m,true); |
---|
| 515 | _pred->set(m,e); |
---|
| 516 | _dist->set(m,_curr_dist); |
---|
[100] | 517 | reach = reach || (target == m); |
---|
[209] | 518 | } |
---|
[100] | 519 | return n; |
---|
| 520 | } |
---|
| 521 | |
---|
| 522 | ///Processes the next node. |
---|
| 523 | |
---|
[244] | 524 | ///Processes the next node and checks if at least one of reached |
---|
| 525 | ///nodes has \c true value in the \c nm node map. If one node |
---|
| 526 | ///with \c true value is reachable from the processed node, then the |
---|
| 527 | ///\c rnode parameter will be set to the first of such nodes. |
---|
[100] | 528 | /// |
---|
[244] | 529 | ///\param nm A \c bool (or convertible) node map that indicates the |
---|
| 530 | ///possible targets. |
---|
[100] | 531 | ///\retval rnode The reached target node. |
---|
[244] | 532 | ///It should be initially \c INVALID. |
---|
| 533 | /// |
---|
[100] | 534 | ///\return The processed node. |
---|
| 535 | /// |
---|
[244] | 536 | ///\pre The queue must not be empty. |
---|
[100] | 537 | template<class NM> |
---|
| 538 | Node processNextNode(const NM& nm, Node& rnode) |
---|
| 539 | { |
---|
| 540 | if(_queue_tail==_queue_next_dist) { |
---|
[209] | 541 | _curr_dist++; |
---|
| 542 | _queue_next_dist=_queue_head; |
---|
[100] | 543 | } |
---|
| 544 | Node n=_queue[_queue_tail++]; |
---|
| 545 | _processed->set(n,true); |
---|
| 546 | Node m; |
---|
| 547 | for(OutArcIt e(*G,n);e!=INVALID;++e) |
---|
[209] | 548 | if(!(*_reached)[m=G->target(e)]) { |
---|
| 549 | _queue[_queue_head++]=m; |
---|
| 550 | _reached->set(m,true); |
---|
| 551 | _pred->set(m,e); |
---|
| 552 | _dist->set(m,_curr_dist); |
---|
| 553 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 554 | } |
---|
[100] | 555 | return n; |
---|
| 556 | } |
---|
[209] | 557 | |
---|
[244] | 558 | ///The next node to be processed. |
---|
[100] | 559 | |
---|
[244] | 560 | ///Returns the next node to be processed or \c INVALID if the queue |
---|
| 561 | ///is empty. |
---|
| 562 | Node nextNode() const |
---|
[209] | 563 | { |
---|
[100] | 564 | return _queue_tail<_queue_head?_queue[_queue_tail]:INVALID; |
---|
| 565 | } |
---|
[209] | 566 | |
---|
[100] | 567 | ///\brief Returns \c false if there are nodes |
---|
[244] | 568 | ///to be processed. |
---|
[100] | 569 | /// |
---|
| 570 | ///Returns \c false if there are nodes |
---|
[244] | 571 | ///to be processed in the queue. |
---|
| 572 | bool emptyQueue() const { return _queue_tail==_queue_head; } |
---|
| 573 | |
---|
[100] | 574 | ///Returns the number of the nodes to be processed. |
---|
[209] | 575 | |
---|
[100] | 576 | ///Returns the number of the nodes to be processed in the queue. |
---|
[244] | 577 | int queueSize() const { return _queue_head-_queue_tail; } |
---|
[209] | 578 | |
---|
[100] | 579 | ///Executes the algorithm. |
---|
| 580 | |
---|
| 581 | ///Executes the algorithm. |
---|
| 582 | /// |
---|
[244] | 583 | ///This method runs the %BFS algorithm from the root node(s) |
---|
| 584 | ///in order to compute the shortest path to each node. |
---|
[100] | 585 | /// |
---|
[244] | 586 | ///The algorithm computes |
---|
| 587 | ///- the shortest path tree (forest), |
---|
| 588 | ///- the distance of each node from the root(s). |
---|
| 589 | /// |
---|
| 590 | ///\pre init() must be called and at least one root node should be |
---|
| 591 | ///added with addSource() before using this function. |
---|
| 592 | /// |
---|
| 593 | ///\note <tt>b.start()</tt> is just a shortcut of the following code. |
---|
| 594 | ///\code |
---|
| 595 | /// while ( !b.emptyQueue() ) { |
---|
| 596 | /// b.processNextNode(); |
---|
| 597 | /// } |
---|
| 598 | ///\endcode |
---|
[100] | 599 | void start() |
---|
| 600 | { |
---|
| 601 | while ( !emptyQueue() ) processNextNode(); |
---|
| 602 | } |
---|
[209] | 603 | |
---|
[244] | 604 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 605 | |
---|
[244] | 606 | ///Executes the algorithm until the given target node is reached. |
---|
[100] | 607 | /// |
---|
| 608 | ///This method runs the %BFS algorithm from the root node(s) |
---|
| 609 | ///in order to compute the shortest path to \c dest. |
---|
[244] | 610 | /// |
---|
[100] | 611 | ///The algorithm computes |
---|
[244] | 612 | ///- the shortest path to \c dest, |
---|
| 613 | ///- the distance of \c dest from the root(s). |
---|
| 614 | /// |
---|
| 615 | ///\pre init() must be called and at least one root node should be |
---|
| 616 | ///added with addSource() before using this function. |
---|
| 617 | /// |
---|
| 618 | ///\note <tt>b.start(t)</tt> is just a shortcut of the following code. |
---|
| 619 | ///\code |
---|
| 620 | /// bool reach = false; |
---|
| 621 | /// while ( !b.emptyQueue() && !reach ) { |
---|
| 622 | /// b.processNextNode(t, reach); |
---|
| 623 | /// } |
---|
| 624 | ///\endcode |
---|
[100] | 625 | void start(Node dest) |
---|
| 626 | { |
---|
| 627 | bool reach = false; |
---|
| 628 | while ( !emptyQueue() && !reach ) processNextNode(dest, reach); |
---|
| 629 | } |
---|
[209] | 630 | |
---|
[100] | 631 | ///Executes the algorithm until a condition is met. |
---|
| 632 | |
---|
| 633 | ///Executes the algorithm until a condition is met. |
---|
| 634 | /// |
---|
[244] | 635 | ///This method runs the %BFS algorithm from the root node(s) in |
---|
| 636 | ///order to compute the shortest path to a node \c v with |
---|
| 637 | /// <tt>nm[v]</tt> true, if such a node can be found. |
---|
[100] | 638 | /// |
---|
[244] | 639 | ///\param nm A \c bool (or convertible) node map. The algorithm |
---|
| 640 | ///will stop when it reaches a node \c v with <tt>nm[v]</tt> true. |
---|
[100] | 641 | /// |
---|
| 642 | ///\return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 643 | ///\c INVALID if no such node was found. |
---|
[244] | 644 | /// |
---|
| 645 | ///\pre init() must be called and at least one root node should be |
---|
| 646 | ///added with addSource() before using this function. |
---|
| 647 | /// |
---|
| 648 | ///\note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
---|
| 649 | ///\code |
---|
| 650 | /// Node rnode = INVALID; |
---|
| 651 | /// while ( !b.emptyQueue() && rnode == INVALID ) { |
---|
| 652 | /// b.processNextNode(nm, rnode); |
---|
| 653 | /// } |
---|
| 654 | /// return rnode; |
---|
| 655 | ///\endcode |
---|
| 656 | template<class NodeBoolMap> |
---|
| 657 | Node start(const NodeBoolMap &nm) |
---|
[100] | 658 | { |
---|
| 659 | Node rnode = INVALID; |
---|
| 660 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 661 | processNextNode(nm, rnode); |
---|
[100] | 662 | } |
---|
| 663 | return rnode; |
---|
| 664 | } |
---|
[209] | 665 | |
---|
[244] | 666 | ///Runs the algorithm from the given node. |
---|
[209] | 667 | |
---|
[244] | 668 | ///This method runs the %BFS algorithm from node \c s |
---|
| 669 | ///in order to compute the shortest path to each node. |
---|
[100] | 670 | /// |
---|
[244] | 671 | ///The algorithm computes |
---|
| 672 | ///- the shortest path tree, |
---|
| 673 | ///- the distance of each node from the root. |
---|
| 674 | /// |
---|
| 675 | ///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 676 | ///\code |
---|
| 677 | /// b.init(); |
---|
| 678 | /// b.addSource(s); |
---|
| 679 | /// b.start(); |
---|
| 680 | ///\endcode |
---|
| 681 | void run(Node s) { |
---|
| 682 | init(); |
---|
| 683 | addSource(s); |
---|
| 684 | start(); |
---|
| 685 | } |
---|
[209] | 686 | |
---|
[100] | 687 | ///Finds the shortest path between \c s and \c t. |
---|
[209] | 688 | |
---|
[244] | 689 | ///This method runs the %BFS algorithm from node \c s |
---|
| 690 | ///in order to compute the shortest path to \c t. |
---|
[100] | 691 | /// |
---|
[244] | 692 | ///\return The length of the shortest <tt>s</tt>--<tt>t</tt> path, |
---|
| 693 | ///if \c t is reachable form \c s, \c 0 otherwise. |
---|
| 694 | /// |
---|
| 695 | ///\note Apart from the return value, <tt>b.run(s,t)</tt> is just a |
---|
| 696 | ///shortcut of the following code. |
---|
[100] | 697 | ///\code |
---|
| 698 | /// b.init(); |
---|
| 699 | /// b.addSource(s); |
---|
| 700 | /// b.start(t); |
---|
| 701 | ///\endcode |
---|
| 702 | int run(Node s,Node t) { |
---|
| 703 | init(); |
---|
| 704 | addSource(s); |
---|
| 705 | start(t); |
---|
| 706 | return reached(t) ? _curr_dist : 0; |
---|
| 707 | } |
---|
[209] | 708 | |
---|
[244] | 709 | ///Runs the algorithm to visit all nodes in the digraph. |
---|
| 710 | |
---|
| 711 | ///This method runs the %BFS algorithm in order to |
---|
| 712 | ///compute the shortest path to each node. |
---|
| 713 | /// |
---|
| 714 | ///The algorithm computes |
---|
| 715 | ///- the shortest path tree (forest), |
---|
| 716 | ///- the distance of each node from the root(s). |
---|
| 717 | /// |
---|
| 718 | ///\note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
| 719 | ///\code |
---|
| 720 | /// b.init(); |
---|
| 721 | /// for (NodeIt n(gr); n != INVALID; ++n) { |
---|
| 722 | /// if (!b.reached(n)) { |
---|
| 723 | /// b.addSource(n); |
---|
| 724 | /// b.start(); |
---|
| 725 | /// } |
---|
| 726 | /// } |
---|
| 727 | ///\endcode |
---|
| 728 | void run() { |
---|
| 729 | init(); |
---|
| 730 | for (NodeIt n(*G); n != INVALID; ++n) { |
---|
| 731 | if (!reached(n)) { |
---|
| 732 | addSource(n); |
---|
| 733 | start(); |
---|
| 734 | } |
---|
| 735 | } |
---|
| 736 | } |
---|
| 737 | |
---|
[100] | 738 | ///@} |
---|
| 739 | |
---|
| 740 | ///\name Query Functions |
---|
| 741 | ///The result of the %BFS algorithm can be obtained using these |
---|
| 742 | ///functions.\n |
---|
[244] | 743 | ///Either \ref lemon::Bfs::run() "run()" or \ref lemon::Bfs::start() |
---|
| 744 | ///"start()" must be called before using them. |
---|
[209] | 745 | |
---|
[100] | 746 | ///@{ |
---|
| 747 | |
---|
[244] | 748 | ///The shortest path to a node. |
---|
[100] | 749 | |
---|
[244] | 750 | ///Returns the shortest path to a node. |
---|
| 751 | /// |
---|
| 752 | ///\warning \c t should be reachable from the root(s). |
---|
| 753 | /// |
---|
| 754 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 755 | ///using this function. |
---|
| 756 | Path path(Node t) const { return Path(*G, *_pred, t); } |
---|
[100] | 757 | |
---|
| 758 | ///The distance of a node from the root(s). |
---|
| 759 | |
---|
| 760 | ///Returns the distance of a node from the root(s). |
---|
[244] | 761 | /// |
---|
| 762 | ///\warning If node \c v is not reachable from the root(s), then |
---|
| 763 | ///the return value of this function is undefined. |
---|
| 764 | /// |
---|
| 765 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 766 | ///using this function. |
---|
[100] | 767 | int dist(Node v) const { return (*_dist)[v]; } |
---|
| 768 | |
---|
[244] | 769 | ///Returns the 'previous arc' of the shortest path tree for a node. |
---|
[100] | 770 | |
---|
[244] | 771 | ///This function returns the 'previous arc' of the shortest path |
---|
| 772 | ///tree for the node \c v, i.e. it returns the last arc of a |
---|
| 773 | ///shortest path from the root(s) to \c v. It is \c INVALID if \c v |
---|
| 774 | ///is not reachable from the root(s) or if \c v is a root. |
---|
| 775 | /// |
---|
| 776 | ///The shortest path tree used here is equal to the shortest path |
---|
| 777 | ///tree used in \ref predNode(). |
---|
| 778 | /// |
---|
| 779 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 780 | ///using this function. |
---|
[100] | 781 | Arc predArc(Node v) const { return (*_pred)[v];} |
---|
| 782 | |
---|
[244] | 783 | ///Returns the 'previous node' of the shortest path tree for a node. |
---|
[100] | 784 | |
---|
[244] | 785 | ///This function returns the 'previous node' of the shortest path |
---|
| 786 | ///tree for the node \c v, i.e. it returns the last but one node |
---|
| 787 | ///from a shortest path from the root(s) to \c v. It is \c INVALID |
---|
| 788 | ///if \c v is not reachable from the root(s) or if \c v is a root. |
---|
| 789 | /// |
---|
[100] | 790 | ///The shortest path tree used here is equal to the shortest path |
---|
| 791 | ///tree used in \ref predArc(). |
---|
[244] | 792 | /// |
---|
[100] | 793 | ///\pre Either \ref run() or \ref start() must be called before |
---|
| 794 | ///using this function. |
---|
| 795 | Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID: |
---|
[209] | 796 | G->source((*_pred)[v]); } |
---|
| 797 | |
---|
[244] | 798 | ///\brief Returns a const reference to the node map that stores the |
---|
| 799 | /// distances of the nodes. |
---|
| 800 | /// |
---|
| 801 | ///Returns a const reference to the node map that stores the distances |
---|
| 802 | ///of the nodes calculated by the algorithm. |
---|
| 803 | /// |
---|
| 804 | ///\pre Either \ref run() or \ref init() |
---|
| 805 | ///must be called before using this function. |
---|
[100] | 806 | const DistMap &distMap() const { return *_dist;} |
---|
[209] | 807 | |
---|
[244] | 808 | ///\brief Returns a const reference to the node map that stores the |
---|
| 809 | ///predecessor arcs. |
---|
| 810 | /// |
---|
| 811 | ///Returns a const reference to the node map that stores the predecessor |
---|
| 812 | ///arcs, which form the shortest path tree. |
---|
| 813 | /// |
---|
[100] | 814 | ///\pre Either \ref run() or \ref init() |
---|
| 815 | ///must be called before using this function. |
---|
| 816 | const PredMap &predMap() const { return *_pred;} |
---|
[209] | 817 | |
---|
[244] | 818 | ///Checks if a node is reachable from the root(s). |
---|
[100] | 819 | |
---|
[244] | 820 | ///Returns \c true if \c v is reachable from the root(s). |
---|
[100] | 821 | ///\pre Either \ref run() or \ref start() |
---|
| 822 | ///must be called before using this function. |
---|
[244] | 823 | bool reached(Node v) const { return (*_reached)[v]; } |
---|
[209] | 824 | |
---|
[100] | 825 | ///@} |
---|
| 826 | }; |
---|
| 827 | |
---|
[244] | 828 | ///Default traits class of bfs() function. |
---|
[100] | 829 | |
---|
[244] | 830 | ///Default traits class of bfs() function. |
---|
[157] | 831 | ///\tparam GR Digraph type. |
---|
[100] | 832 | template<class GR> |
---|
| 833 | struct BfsWizardDefaultTraits |
---|
| 834 | { |
---|
[244] | 835 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 836 | typedef GR Digraph; |
---|
[244] | 837 | |
---|
| 838 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 839 | ///arcs of the shortest paths. |
---|
[209] | 840 | /// |
---|
[244] | 841 | ///The type of the map that stores the predecessor |
---|
[100] | 842 | ///arcs of the shortest paths. |
---|
| 843 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
[244] | 844 | typedef NullMap<typename Digraph::Node,typename Digraph::Arc> PredMap; |
---|
| 845 | ///Instantiates a \ref PredMap. |
---|
[209] | 846 | |
---|
| 847 | ///This function instantiates a \ref PredMap. |
---|
[244] | 848 | ///\param g is the digraph, to which we would like to define the |
---|
| 849 | ///\ref PredMap. |
---|
[100] | 850 | ///\todo The digraph alone may be insufficient to initialize |
---|
| 851 | #ifdef DOXYGEN |
---|
[244] | 852 | static PredMap *createPredMap(const Digraph &g) |
---|
[100] | 853 | #else |
---|
[244] | 854 | static PredMap *createPredMap(const Digraph &) |
---|
[100] | 855 | #endif |
---|
| 856 | { |
---|
| 857 | return new PredMap(); |
---|
| 858 | } |
---|
| 859 | |
---|
| 860 | ///The type of the map that indicates which nodes are processed. |
---|
[209] | 861 | |
---|
[100] | 862 | ///The type of the map that indicates which nodes are processed. |
---|
| 863 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 864 | typedef NullMap<typename Digraph::Node,bool> ProcessedMap; |
---|
[244] | 865 | ///Instantiates a \ref ProcessedMap. |
---|
[209] | 866 | |
---|
| 867 | ///This function instantiates a \ref ProcessedMap. |
---|
[100] | 868 | ///\param g is the digraph, to which |
---|
[244] | 869 | ///we would like to define the \ref ProcessedMap. |
---|
[100] | 870 | #ifdef DOXYGEN |
---|
[244] | 871 | static ProcessedMap *createProcessedMap(const Digraph &g) |
---|
[100] | 872 | #else |
---|
[244] | 873 | static ProcessedMap *createProcessedMap(const Digraph &) |
---|
[100] | 874 | #endif |
---|
| 875 | { |
---|
| 876 | return new ProcessedMap(); |
---|
| 877 | } |
---|
[244] | 878 | |
---|
[100] | 879 | ///The type of the map that indicates which nodes are reached. |
---|
[209] | 880 | |
---|
[100] | 881 | ///The type of the map that indicates which nodes are reached. |
---|
[244] | 882 | ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 883 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
[244] | 884 | ///Instantiates a \ref ReachedMap. |
---|
[209] | 885 | |
---|
| 886 | ///This function instantiates a \ref ReachedMap. |
---|
[244] | 887 | ///\param g is the digraph, to which |
---|
[100] | 888 | ///we would like to define the \ref ReachedMap. |
---|
[244] | 889 | static ReachedMap *createReachedMap(const Digraph &g) |
---|
[100] | 890 | { |
---|
[244] | 891 | return new ReachedMap(g); |
---|
[100] | 892 | } |
---|
[209] | 893 | |
---|
[244] | 894 | ///The type of the map that stores the distances of the nodes. |
---|
| 895 | |
---|
| 896 | ///The type of the map that stores the distances of the nodes. |
---|
[100] | 897 | ///It must meet the \ref concepts::WriteMap "WriteMap" concept. |
---|
| 898 | /// |
---|
| 899 | typedef NullMap<typename Digraph::Node,int> DistMap; |
---|
[244] | 900 | ///Instantiates a \ref DistMap. |
---|
[209] | 901 | |
---|
| 902 | ///This function instantiates a \ref DistMap. |
---|
[210] | 903 | ///\param g is the digraph, to which we would like to define |
---|
| 904 | ///the \ref DistMap |
---|
[100] | 905 | #ifdef DOXYGEN |
---|
[244] | 906 | static DistMap *createDistMap(const Digraph &g) |
---|
[100] | 907 | #else |
---|
[244] | 908 | static DistMap *createDistMap(const Digraph &) |
---|
[100] | 909 | #endif |
---|
| 910 | { |
---|
| 911 | return new DistMap(); |
---|
| 912 | } |
---|
| 913 | }; |
---|
[209] | 914 | |
---|
[244] | 915 | /// Default traits class used by \ref BfsWizard |
---|
[100] | 916 | |
---|
| 917 | /// To make it easier to use Bfs algorithm |
---|
[244] | 918 | /// we have created a wizard class. |
---|
[100] | 919 | /// This \ref BfsWizard class needs default traits, |
---|
[244] | 920 | /// as well as the \ref Bfs class. |
---|
[100] | 921 | /// The \ref BfsWizardBase is a class to be the default traits of the |
---|
| 922 | /// \ref BfsWizard class. |
---|
| 923 | template<class GR> |
---|
| 924 | class BfsWizardBase : public BfsWizardDefaultTraits<GR> |
---|
| 925 | { |
---|
| 926 | |
---|
| 927 | typedef BfsWizardDefaultTraits<GR> Base; |
---|
| 928 | protected: |
---|
[244] | 929 | //The type of the nodes in the digraph. |
---|
[100] | 930 | typedef typename Base::Digraph::Node Node; |
---|
| 931 | |
---|
[244] | 932 | //Pointer to the digraph the algorithm runs on. |
---|
[100] | 933 | void *_g; |
---|
[244] | 934 | //Pointer to the map of reached nodes. |
---|
[100] | 935 | void *_reached; |
---|
[244] | 936 | //Pointer to the map of processed nodes. |
---|
[100] | 937 | void *_processed; |
---|
[244] | 938 | //Pointer to the map of predecessors arcs. |
---|
[100] | 939 | void *_pred; |
---|
[244] | 940 | //Pointer to the map of distances. |
---|
[100] | 941 | void *_dist; |
---|
[244] | 942 | //Pointer to the source node. |
---|
[100] | 943 | Node _source; |
---|
[209] | 944 | |
---|
[100] | 945 | public: |
---|
| 946 | /// Constructor. |
---|
[209] | 947 | |
---|
[100] | 948 | /// This constructor does not require parameters, therefore it initiates |
---|
| 949 | /// all of the attributes to default values (0, INVALID). |
---|
| 950 | BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0), |
---|
[244] | 951 | _dist(0), _source(INVALID) {} |
---|
[100] | 952 | |
---|
| 953 | /// Constructor. |
---|
[209] | 954 | |
---|
[100] | 955 | /// This constructor requires some parameters, |
---|
| 956 | /// listed in the parameters list. |
---|
| 957 | /// Others are initiated to 0. |
---|
[244] | 958 | /// \param g The digraph the algorithm runs on. |
---|
| 959 | /// \param s The source node. |
---|
[100] | 960 | BfsWizardBase(const GR &g, Node s=INVALID) : |
---|
[209] | 961 | _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), |
---|
[100] | 962 | _reached(0), _processed(0), _pred(0), _dist(0), _source(s) {} |
---|
| 963 | |
---|
| 964 | }; |
---|
[209] | 965 | |
---|
[244] | 966 | /// Auxiliary class for the function type interface of BFS algorithm. |
---|
[100] | 967 | |
---|
[244] | 968 | /// This auxiliary class is created to implement the function type |
---|
| 969 | /// interface of \ref Bfs algorithm. It uses the functions and features |
---|
| 970 | /// of the plain \ref Bfs, but it is much simpler to use it. |
---|
| 971 | /// It should only be used through the \ref bfs() function, which makes |
---|
| 972 | /// it easier to use the algorithm. |
---|
[100] | 973 | /// |
---|
| 974 | /// Simplicity means that the way to change the types defined |
---|
| 975 | /// in the traits class is based on functions that returns the new class |
---|
| 976 | /// and not on templatable built-in classes. |
---|
| 977 | /// When using the plain \ref Bfs |
---|
| 978 | /// the new class with the modified type comes from |
---|
| 979 | /// the original class by using the :: |
---|
| 980 | /// operator. In the case of \ref BfsWizard only |
---|
[244] | 981 | /// a function have to be called, and it will |
---|
[100] | 982 | /// return the needed class. |
---|
| 983 | /// |
---|
[244] | 984 | /// It does not have own \ref run() method. When its \ref run() method |
---|
| 985 | /// is called, it initiates a plain \ref Bfs object, and calls the |
---|
| 986 | /// \ref Bfs::run() method of it. |
---|
[100] | 987 | template<class TR> |
---|
| 988 | class BfsWizard : public TR |
---|
| 989 | { |
---|
| 990 | typedef TR Base; |
---|
| 991 | |
---|
[244] | 992 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 993 | typedef typename TR::Digraph Digraph; |
---|
[244] | 994 | |
---|
[100] | 995 | typedef typename Digraph::Node Node; |
---|
| 996 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 997 | typedef typename Digraph::Arc Arc; |
---|
| 998 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
[209] | 999 | |
---|
[244] | 1000 | ///\brief The type of the map that stores the predecessor |
---|
[100] | 1001 | ///arcs of the shortest paths. |
---|
| 1002 | typedef typename TR::PredMap PredMap; |
---|
[244] | 1003 | ///\brief The type of the map that stores the distances of the nodes. |
---|
[100] | 1004 | typedef typename TR::DistMap DistMap; |
---|
[244] | 1005 | ///\brief The type of the map that indicates which nodes are reached. |
---|
| 1006 | typedef typename TR::ReachedMap ReachedMap; |
---|
| 1007 | ///\brief The type of the map that indicates which nodes are processed. |
---|
| 1008 | typedef typename TR::ProcessedMap ProcessedMap; |
---|
[100] | 1009 | |
---|
| 1010 | public: |
---|
[244] | 1011 | |
---|
[100] | 1012 | /// Constructor. |
---|
| 1013 | BfsWizard() : TR() {} |
---|
| 1014 | |
---|
| 1015 | /// Constructor that requires parameters. |
---|
| 1016 | |
---|
| 1017 | /// Constructor that requires parameters. |
---|
| 1018 | /// These parameters will be the default values for the traits class. |
---|
| 1019 | BfsWizard(const Digraph &g, Node s=INVALID) : |
---|
| 1020 | TR(g,s) {} |
---|
| 1021 | |
---|
| 1022 | ///Copy constructor |
---|
| 1023 | BfsWizard(const TR &b) : TR(b) {} |
---|
| 1024 | |
---|
| 1025 | ~BfsWizard() {} |
---|
| 1026 | |
---|
[244] | 1027 | ///Runs BFS algorithm from a source node. |
---|
[209] | 1028 | |
---|
[244] | 1029 | ///Runs BFS algorithm from a source node. |
---|
| 1030 | ///The node can be given with the \ref source() function. |
---|
[100] | 1031 | void run() |
---|
| 1032 | { |
---|
| 1033 | if(Base::_source==INVALID) throw UninitializedParameter(); |
---|
| 1034 | Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g)); |
---|
| 1035 | if(Base::_reached) |
---|
[209] | 1036 | alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached)); |
---|
| 1037 | if(Base::_processed) |
---|
[100] | 1038 | alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed)); |
---|
[209] | 1039 | if(Base::_pred) |
---|
[100] | 1040 | alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred)); |
---|
[209] | 1041 | if(Base::_dist) |
---|
[100] | 1042 | alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist)); |
---|
| 1043 | alg.run(Base::_source); |
---|
| 1044 | } |
---|
| 1045 | |
---|
[244] | 1046 | ///Runs BFS algorithm from the given node. |
---|
[100] | 1047 | |
---|
[244] | 1048 | ///Runs BFS algorithm from the given node. |
---|
[100] | 1049 | ///\param s is the given source. |
---|
| 1050 | void run(Node s) |
---|
| 1051 | { |
---|
| 1052 | Base::_source=s; |
---|
| 1053 | run(); |
---|
| 1054 | } |
---|
| 1055 | |
---|
| 1056 | /// Sets the source node, from which the Bfs algorithm runs. |
---|
| 1057 | |
---|
| 1058 | /// Sets the source node, from which the Bfs algorithm runs. |
---|
| 1059 | /// \param s is the source node. |
---|
[209] | 1060 | BfsWizard<TR> &source(Node s) |
---|
[100] | 1061 | { |
---|
| 1062 | Base::_source=s; |
---|
| 1063 | return *this; |
---|
| 1064 | } |
---|
[209] | 1065 | |
---|
[244] | 1066 | template<class T> |
---|
[257] | 1067 | struct SetPredMapBase : public Base { |
---|
[244] | 1068 | typedef T PredMap; |
---|
| 1069 | static PredMap *createPredMap(const Digraph &) { return 0; }; |
---|
[257] | 1070 | SetPredMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1071 | }; |
---|
| 1072 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1073 | ///for setting \ref PredMap object. |
---|
| 1074 | /// |
---|
| 1075 | /// \ref named-templ-param "Named parameter" |
---|
| 1076 | ///for setting \ref PredMap object. |
---|
| 1077 | template<class T> |
---|
[257] | 1078 | BfsWizard<SetPredMapBase<T> > predMap(const T &t) |
---|
[244] | 1079 | { |
---|
| 1080 | Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1081 | return BfsWizard<SetPredMapBase<T> >(*this); |
---|
[244] | 1082 | } |
---|
| 1083 | |
---|
| 1084 | template<class T> |
---|
[257] | 1085 | struct SetReachedMapBase : public Base { |
---|
[244] | 1086 | typedef T ReachedMap; |
---|
| 1087 | static ReachedMap *createReachedMap(const Digraph &) { return 0; }; |
---|
[257] | 1088 | SetReachedMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1089 | }; |
---|
| 1090 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1091 | ///for setting \ref ReachedMap object. |
---|
| 1092 | /// |
---|
| 1093 | /// \ref named-templ-param "Named parameter" |
---|
| 1094 | ///for setting \ref ReachedMap object. |
---|
| 1095 | template<class T> |
---|
[257] | 1096 | BfsWizard<SetReachedMapBase<T> > reachedMap(const T &t) |
---|
[244] | 1097 | { |
---|
| 1098 | Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1099 | return BfsWizard<SetReachedMapBase<T> >(*this); |
---|
[244] | 1100 | } |
---|
| 1101 | |
---|
| 1102 | template<class T> |
---|
[257] | 1103 | struct SetProcessedMapBase : public Base { |
---|
[244] | 1104 | typedef T ProcessedMap; |
---|
| 1105 | static ProcessedMap *createProcessedMap(const Digraph &) { return 0; }; |
---|
[257] | 1106 | SetProcessedMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1107 | }; |
---|
| 1108 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1109 | ///for setting \ref ProcessedMap object. |
---|
| 1110 | /// |
---|
| 1111 | /// \ref named-templ-param "Named parameter" |
---|
| 1112 | ///for setting \ref ProcessedMap object. |
---|
| 1113 | template<class T> |
---|
[257] | 1114 | BfsWizard<SetProcessedMapBase<T> > processedMap(const T &t) |
---|
[244] | 1115 | { |
---|
| 1116 | Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1117 | return BfsWizard<SetProcessedMapBase<T> >(*this); |
---|
[244] | 1118 | } |
---|
| 1119 | |
---|
| 1120 | template<class T> |
---|
[257] | 1121 | struct SetDistMapBase : public Base { |
---|
[244] | 1122 | typedef T DistMap; |
---|
| 1123 | static DistMap *createDistMap(const Digraph &) { return 0; }; |
---|
[257] | 1124 | SetDistMapBase(const TR &b) : TR(b) {} |
---|
[244] | 1125 | }; |
---|
| 1126 | ///\brief \ref named-templ-param "Named parameter" |
---|
| 1127 | ///for setting \ref DistMap object. |
---|
| 1128 | /// |
---|
| 1129 | /// \ref named-templ-param "Named parameter" |
---|
| 1130 | ///for setting \ref DistMap object. |
---|
| 1131 | template<class T> |
---|
[257] | 1132 | BfsWizard<SetDistMapBase<T> > distMap(const T &t) |
---|
[244] | 1133 | { |
---|
| 1134 | Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t)); |
---|
[257] | 1135 | return BfsWizard<SetDistMapBase<T> >(*this); |
---|
[244] | 1136 | } |
---|
| 1137 | |
---|
[100] | 1138 | }; |
---|
[209] | 1139 | |
---|
[100] | 1140 | ///Function type interface for Bfs algorithm. |
---|
| 1141 | |
---|
| 1142 | /// \ingroup search |
---|
| 1143 | ///Function type interface for Bfs algorithm. |
---|
| 1144 | /// |
---|
| 1145 | ///This function also has several |
---|
| 1146 | ///\ref named-templ-func-param "named parameters", |
---|
| 1147 | ///they are declared as the members of class \ref BfsWizard. |
---|
| 1148 | ///The following |
---|
| 1149 | ///example shows how to use these parameters. |
---|
| 1150 | ///\code |
---|
| 1151 | /// bfs(g,source).predMap(preds).run(); |
---|
| 1152 | ///\endcode |
---|
| 1153 | ///\warning Don't forget to put the \ref BfsWizard::run() "run()" |
---|
| 1154 | ///to the end of the parameter list. |
---|
| 1155 | ///\sa BfsWizard |
---|
| 1156 | ///\sa Bfs |
---|
| 1157 | template<class GR> |
---|
| 1158 | BfsWizard<BfsWizardBase<GR> > |
---|
| 1159 | bfs(const GR &g,typename GR::Node s=INVALID) |
---|
| 1160 | { |
---|
| 1161 | return BfsWizard<BfsWizardBase<GR> >(g,s); |
---|
| 1162 | } |
---|
| 1163 | |
---|
| 1164 | #ifdef DOXYGEN |
---|
[244] | 1165 | /// \brief Visitor class for BFS. |
---|
[209] | 1166 | /// |
---|
[100] | 1167 | /// This class defines the interface of the BfsVisit events, and |
---|
[244] | 1168 | /// it could be the base of a real visitor class. |
---|
[100] | 1169 | template <typename _Digraph> |
---|
| 1170 | struct BfsVisitor { |
---|
| 1171 | typedef _Digraph Digraph; |
---|
| 1172 | typedef typename Digraph::Arc Arc; |
---|
| 1173 | typedef typename Digraph::Node Node; |
---|
[244] | 1174 | /// \brief Called for the source node(s) of the BFS. |
---|
[209] | 1175 | /// |
---|
[244] | 1176 | /// This function is called for the source node(s) of the BFS. |
---|
| 1177 | void start(const Node& node) {} |
---|
| 1178 | /// \brief Called when a node is reached first time. |
---|
| 1179 | /// |
---|
| 1180 | /// This function is called when a node is reached first time. |
---|
| 1181 | void reach(const Node& node) {} |
---|
| 1182 | /// \brief Called when a node is processed. |
---|
| 1183 | /// |
---|
| 1184 | /// This function is called when a node is processed. |
---|
| 1185 | void process(const Node& node) {} |
---|
| 1186 | /// \brief Called when an arc reaches a new node. |
---|
| 1187 | /// |
---|
| 1188 | /// This function is called when the BFS finds an arc whose target node |
---|
| 1189 | /// is not reached yet. |
---|
[100] | 1190 | void discover(const Arc& arc) {} |
---|
[244] | 1191 | /// \brief Called when an arc is examined but its target node is |
---|
[100] | 1192 | /// already discovered. |
---|
[209] | 1193 | /// |
---|
[244] | 1194 | /// This function is called when an arc is examined but its target node is |
---|
[100] | 1195 | /// already discovered. |
---|
| 1196 | void examine(const Arc& arc) {} |
---|
| 1197 | }; |
---|
| 1198 | #else |
---|
| 1199 | template <typename _Digraph> |
---|
| 1200 | struct BfsVisitor { |
---|
| 1201 | typedef _Digraph Digraph; |
---|
| 1202 | typedef typename Digraph::Arc Arc; |
---|
| 1203 | typedef typename Digraph::Node Node; |
---|
[244] | 1204 | void start(const Node&) {} |
---|
| 1205 | void reach(const Node&) {} |
---|
| 1206 | void process(const Node&) {} |
---|
[100] | 1207 | void discover(const Arc&) {} |
---|
| 1208 | void examine(const Arc&) {} |
---|
| 1209 | |
---|
| 1210 | template <typename _Visitor> |
---|
| 1211 | struct Constraints { |
---|
| 1212 | void constraints() { |
---|
[209] | 1213 | Arc arc; |
---|
| 1214 | Node node; |
---|
[244] | 1215 | visitor.start(node); |
---|
| 1216 | visitor.reach(node); |
---|
| 1217 | visitor.process(node); |
---|
[209] | 1218 | visitor.discover(arc); |
---|
| 1219 | visitor.examine(arc); |
---|
[100] | 1220 | } |
---|
| 1221 | _Visitor& visitor; |
---|
| 1222 | }; |
---|
| 1223 | }; |
---|
| 1224 | #endif |
---|
| 1225 | |
---|
| 1226 | /// \brief Default traits class of BfsVisit class. |
---|
| 1227 | /// |
---|
| 1228 | /// Default traits class of BfsVisit class. |
---|
[244] | 1229 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[100] | 1230 | template<class _Digraph> |
---|
| 1231 | struct BfsVisitDefaultTraits { |
---|
| 1232 | |
---|
[244] | 1233 | /// \brief The type of the digraph the algorithm runs on. |
---|
[100] | 1234 | typedef _Digraph Digraph; |
---|
| 1235 | |
---|
| 1236 | /// \brief The type of the map that indicates which nodes are reached. |
---|
[209] | 1237 | /// |
---|
[100] | 1238 | /// The type of the map that indicates which nodes are reached. |
---|
[244] | 1239 | /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. |
---|
[100] | 1240 | typedef typename Digraph::template NodeMap<bool> ReachedMap; |
---|
| 1241 | |
---|
[244] | 1242 | /// \brief Instantiates a \ref ReachedMap. |
---|
[100] | 1243 | /// |
---|
[209] | 1244 | /// This function instantiates a \ref ReachedMap. |
---|
[100] | 1245 | /// \param digraph is the digraph, to which |
---|
| 1246 | /// we would like to define the \ref ReachedMap. |
---|
| 1247 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
| 1248 | return new ReachedMap(digraph); |
---|
| 1249 | } |
---|
| 1250 | |
---|
| 1251 | }; |
---|
| 1252 | |
---|
| 1253 | /// \ingroup search |
---|
[209] | 1254 | /// |
---|
[244] | 1255 | /// \brief %BFS algorithm class with visitor interface. |
---|
[209] | 1256 | /// |
---|
[100] | 1257 | /// This class provides an efficient implementation of the %BFS algorithm |
---|
| 1258 | /// with visitor interface. |
---|
| 1259 | /// |
---|
| 1260 | /// The %BfsVisit class provides an alternative interface to the Bfs |
---|
| 1261 | /// class. It works with callback mechanism, the BfsVisit object calls |
---|
[244] | 1262 | /// the member functions of the \c Visitor class on every BFS event. |
---|
[100] | 1263 | /// |
---|
[252] | 1264 | /// This interface of the BFS algorithm should be used in special cases |
---|
| 1265 | /// when extra actions have to be performed in connection with certain |
---|
| 1266 | /// events of the BFS algorithm. Otherwise consider to use Bfs or bfs() |
---|
| 1267 | /// instead. |
---|
| 1268 | /// |
---|
[244] | 1269 | /// \tparam _Digraph The type of the digraph the algorithm runs on. |
---|
[210] | 1270 | /// The default value is |
---|
[244] | 1271 | /// \ref ListDigraph. The value of _Digraph is not used directly by |
---|
| 1272 | /// \ref BfsVisit, it is only passed to \ref BfsVisitDefaultTraits. |
---|
| 1273 | /// \tparam _Visitor The Visitor type that is used by the algorithm. |
---|
| 1274 | /// \ref BfsVisitor "BfsVisitor<_Digraph>" is an empty visitor, which |
---|
| 1275 | /// does not observe the BFS events. If you want to observe the BFS |
---|
| 1276 | /// events, you should implement your own visitor class. |
---|
[209] | 1277 | /// \tparam _Traits Traits class to set various data types used by the |
---|
[100] | 1278 | /// algorithm. The default traits class is |
---|
| 1279 | /// \ref BfsVisitDefaultTraits "BfsVisitDefaultTraits<_Digraph>". |
---|
| 1280 | /// See \ref BfsVisitDefaultTraits for the documentation of |
---|
[244] | 1281 | /// a BFS visit traits class. |
---|
[100] | 1282 | #ifdef DOXYGEN |
---|
| 1283 | template <typename _Digraph, typename _Visitor, typename _Traits> |
---|
| 1284 | #else |
---|
| 1285 | template <typename _Digraph = ListDigraph, |
---|
[209] | 1286 | typename _Visitor = BfsVisitor<_Digraph>, |
---|
| 1287 | typename _Traits = BfsDefaultTraits<_Digraph> > |
---|
[100] | 1288 | #endif |
---|
| 1289 | class BfsVisit { |
---|
| 1290 | public: |
---|
[209] | 1291 | |
---|
[100] | 1292 | /// \brief \ref Exception for uninitialized parameters. |
---|
| 1293 | /// |
---|
| 1294 | /// This error represents problems in the initialization |
---|
[244] | 1295 | /// of the parameters of the algorithm. |
---|
[100] | 1296 | class UninitializedParameter : public lemon::UninitializedParameter { |
---|
| 1297 | public: |
---|
[209] | 1298 | virtual const char* what() const throw() |
---|
[100] | 1299 | { |
---|
[209] | 1300 | return "lemon::BfsVisit::UninitializedParameter"; |
---|
[100] | 1301 | } |
---|
| 1302 | }; |
---|
| 1303 | |
---|
[244] | 1304 | ///The traits class. |
---|
[100] | 1305 | typedef _Traits Traits; |
---|
| 1306 | |
---|
[244] | 1307 | ///The type of the digraph the algorithm runs on. |
---|
[100] | 1308 | typedef typename Traits::Digraph Digraph; |
---|
| 1309 | |
---|
[244] | 1310 | ///The visitor type used by the algorithm. |
---|
[100] | 1311 | typedef _Visitor Visitor; |
---|
| 1312 | |
---|
[244] | 1313 | ///The type of the map that indicates which nodes are reached. |
---|
[100] | 1314 | typedef typename Traits::ReachedMap ReachedMap; |
---|
| 1315 | |
---|
| 1316 | private: |
---|
| 1317 | |
---|
| 1318 | typedef typename Digraph::Node Node; |
---|
| 1319 | typedef typename Digraph::NodeIt NodeIt; |
---|
| 1320 | typedef typename Digraph::Arc Arc; |
---|
| 1321 | typedef typename Digraph::OutArcIt OutArcIt; |
---|
| 1322 | |
---|
[244] | 1323 | //Pointer to the underlying digraph. |
---|
[100] | 1324 | const Digraph *_digraph; |
---|
[244] | 1325 | //Pointer to the visitor object. |
---|
[100] | 1326 | Visitor *_visitor; |
---|
[244] | 1327 | //Pointer to the map of reached status of the nodes. |
---|
[100] | 1328 | ReachedMap *_reached; |
---|
[244] | 1329 | //Indicates if _reached is locally allocated (true) or not. |
---|
[100] | 1330 | bool local_reached; |
---|
| 1331 | |
---|
| 1332 | std::vector<typename Digraph::Node> _list; |
---|
| 1333 | int _list_front, _list_back; |
---|
| 1334 | |
---|
[244] | 1335 | ///Creates the maps if necessary. |
---|
| 1336 | ///\todo Better memory allocation (instead of new). |
---|
[100] | 1337 | void create_maps() { |
---|
| 1338 | if(!_reached) { |
---|
[209] | 1339 | local_reached = true; |
---|
| 1340 | _reached = Traits::createReachedMap(*_digraph); |
---|
[100] | 1341 | } |
---|
| 1342 | } |
---|
| 1343 | |
---|
| 1344 | protected: |
---|
| 1345 | |
---|
| 1346 | BfsVisit() {} |
---|
[209] | 1347 | |
---|
[100] | 1348 | public: |
---|
| 1349 | |
---|
| 1350 | typedef BfsVisit Create; |
---|
| 1351 | |
---|
| 1352 | /// \name Named template parameters |
---|
| 1353 | |
---|
| 1354 | ///@{ |
---|
| 1355 | template <class T> |
---|
[257] | 1356 | struct SetReachedMapTraits : public Traits { |
---|
[100] | 1357 | typedef T ReachedMap; |
---|
| 1358 | static ReachedMap *createReachedMap(const Digraph &digraph) { |
---|
[209] | 1359 | throw UninitializedParameter(); |
---|
[100] | 1360 | } |
---|
| 1361 | }; |
---|
[209] | 1362 | /// \brief \ref named-templ-param "Named parameter" for setting |
---|
[244] | 1363 | /// ReachedMap type. |
---|
[100] | 1364 | /// |
---|
[244] | 1365 | /// \ref named-templ-param "Named parameter" for setting ReachedMap type. |
---|
[100] | 1366 | template <class T> |
---|
[257] | 1367 | struct SetReachedMap : public BfsVisit< Digraph, Visitor, |
---|
| 1368 | SetReachedMapTraits<T> > { |
---|
| 1369 | typedef BfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create; |
---|
[100] | 1370 | }; |
---|
| 1371 | ///@} |
---|
| 1372 | |
---|
[209] | 1373 | public: |
---|
| 1374 | |
---|
[100] | 1375 | /// \brief Constructor. |
---|
| 1376 | /// |
---|
| 1377 | /// Constructor. |
---|
| 1378 | /// |
---|
[244] | 1379 | /// \param digraph The digraph the algorithm runs on. |
---|
| 1380 | /// \param visitor The visitor object of the algorithm. |
---|
[209] | 1381 | BfsVisit(const Digraph& digraph, Visitor& visitor) |
---|
[100] | 1382 | : _digraph(&digraph), _visitor(&visitor), |
---|
[209] | 1383 | _reached(0), local_reached(false) {} |
---|
| 1384 | |
---|
[100] | 1385 | /// \brief Destructor. |
---|
| 1386 | ~BfsVisit() { |
---|
| 1387 | if(local_reached) delete _reached; |
---|
| 1388 | } |
---|
| 1389 | |
---|
[244] | 1390 | /// \brief Sets the map that indicates which nodes are reached. |
---|
[100] | 1391 | /// |
---|
[244] | 1392 | /// Sets the map that indicates which nodes are reached. |
---|
[100] | 1393 | /// If you don't use this function before calling \ref run(), |
---|
[244] | 1394 | /// it will allocate one. The destructor deallocates this |
---|
[100] | 1395 | /// automatically allocated map, of course. |
---|
| 1396 | /// \return <tt> (*this) </tt> |
---|
| 1397 | BfsVisit &reachedMap(ReachedMap &m) { |
---|
| 1398 | if(local_reached) { |
---|
[209] | 1399 | delete _reached; |
---|
| 1400 | local_reached = false; |
---|
[100] | 1401 | } |
---|
| 1402 | _reached = &m; |
---|
| 1403 | return *this; |
---|
| 1404 | } |
---|
| 1405 | |
---|
| 1406 | public: |
---|
[244] | 1407 | |
---|
[100] | 1408 | /// \name Execution control |
---|
| 1409 | /// The simplest way to execute the algorithm is to use |
---|
[244] | 1410 | /// one of the member functions called \ref lemon::BfsVisit::run() |
---|
| 1411 | /// "run()". |
---|
[100] | 1412 | /// \n |
---|
[244] | 1413 | /// If you need more control on the execution, first you must call |
---|
| 1414 | /// \ref lemon::BfsVisit::init() "init()", then you can add several |
---|
| 1415 | /// source nodes with \ref lemon::BfsVisit::addSource() "addSource()". |
---|
| 1416 | /// Finally \ref lemon::BfsVisit::start() "start()" will perform the |
---|
| 1417 | /// actual path computation. |
---|
[100] | 1418 | |
---|
| 1419 | /// @{ |
---|
[244] | 1420 | |
---|
[100] | 1421 | /// \brief Initializes the internal data structures. |
---|
| 1422 | /// |
---|
| 1423 | /// Initializes the internal data structures. |
---|
| 1424 | void init() { |
---|
| 1425 | create_maps(); |
---|
| 1426 | _list.resize(countNodes(*_digraph)); |
---|
| 1427 | _list_front = _list_back = -1; |
---|
| 1428 | for (NodeIt u(*_digraph) ; u != INVALID ; ++u) { |
---|
[209] | 1429 | _reached->set(u, false); |
---|
[100] | 1430 | } |
---|
| 1431 | } |
---|
[209] | 1432 | |
---|
[100] | 1433 | /// \brief Adds a new source node. |
---|
| 1434 | /// |
---|
| 1435 | /// Adds a new source node to the set of nodes to be processed. |
---|
| 1436 | void addSource(Node s) { |
---|
| 1437 | if(!(*_reached)[s]) { |
---|
[209] | 1438 | _reached->set(s,true); |
---|
| 1439 | _visitor->start(s); |
---|
| 1440 | _visitor->reach(s); |
---|
[100] | 1441 | _list[++_list_back] = s; |
---|
[209] | 1442 | } |
---|
[100] | 1443 | } |
---|
[209] | 1444 | |
---|
[100] | 1445 | /// \brief Processes the next node. |
---|
| 1446 | /// |
---|
| 1447 | /// Processes the next node. |
---|
| 1448 | /// |
---|
| 1449 | /// \return The processed node. |
---|
| 1450 | /// |
---|
[244] | 1451 | /// \pre The queue must not be empty. |
---|
[209] | 1452 | Node processNextNode() { |
---|
[100] | 1453 | Node n = _list[++_list_front]; |
---|
| 1454 | _visitor->process(n); |
---|
| 1455 | Arc e; |
---|
| 1456 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1457 | Node m = _digraph->target(e); |
---|
| 1458 | if (!(*_reached)[m]) { |
---|
| 1459 | _visitor->discover(e); |
---|
| 1460 | _visitor->reach(m); |
---|
| 1461 | _reached->set(m, true); |
---|
| 1462 | _list[++_list_back] = m; |
---|
| 1463 | } else { |
---|
| 1464 | _visitor->examine(e); |
---|
| 1465 | } |
---|
| 1466 | } |
---|
| 1467 | return n; |
---|
| 1468 | } |
---|
| 1469 | |
---|
| 1470 | /// \brief Processes the next node. |
---|
| 1471 | /// |
---|
[244] | 1472 | /// Processes the next node and checks if the given target node |
---|
[100] | 1473 | /// is reached. If the target node is reachable from the processed |
---|
[244] | 1474 | /// node, then the \c reach parameter will be set to \c true. |
---|
[100] | 1475 | /// |
---|
| 1476 | /// \param target The target node. |
---|
[244] | 1477 | /// \retval reach Indicates if the target node is reached. |
---|
| 1478 | /// It should be initially \c false. |
---|
| 1479 | /// |
---|
[100] | 1480 | /// \return The processed node. |
---|
| 1481 | /// |
---|
[244] | 1482 | /// \pre The queue must not be empty. |
---|
[100] | 1483 | Node processNextNode(Node target, bool& reach) { |
---|
| 1484 | Node n = _list[++_list_front]; |
---|
| 1485 | _visitor->process(n); |
---|
| 1486 | Arc e; |
---|
| 1487 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1488 | Node m = _digraph->target(e); |
---|
| 1489 | if (!(*_reached)[m]) { |
---|
| 1490 | _visitor->discover(e); |
---|
| 1491 | _visitor->reach(m); |
---|
| 1492 | _reached->set(m, true); |
---|
| 1493 | _list[++_list_back] = m; |
---|
| 1494 | reach = reach || (target == m); |
---|
| 1495 | } else { |
---|
| 1496 | _visitor->examine(e); |
---|
| 1497 | } |
---|
| 1498 | } |
---|
| 1499 | return n; |
---|
| 1500 | } |
---|
| 1501 | |
---|
| 1502 | /// \brief Processes the next node. |
---|
| 1503 | /// |
---|
[244] | 1504 | /// Processes the next node and checks if at least one of reached |
---|
| 1505 | /// nodes has \c true value in the \c nm node map. If one node |
---|
| 1506 | /// with \c true value is reachable from the processed node, then the |
---|
| 1507 | /// \c rnode parameter will be set to the first of such nodes. |
---|
[100] | 1508 | /// |
---|
[244] | 1509 | /// \param nm A \c bool (or convertible) node map that indicates the |
---|
| 1510 | /// possible targets. |
---|
[100] | 1511 | /// \retval rnode The reached target node. |
---|
[244] | 1512 | /// It should be initially \c INVALID. |
---|
| 1513 | /// |
---|
[100] | 1514 | /// \return The processed node. |
---|
| 1515 | /// |
---|
[244] | 1516 | /// \pre The queue must not be empty. |
---|
[100] | 1517 | template <typename NM> |
---|
| 1518 | Node processNextNode(const NM& nm, Node& rnode) { |
---|
| 1519 | Node n = _list[++_list_front]; |
---|
| 1520 | _visitor->process(n); |
---|
| 1521 | Arc e; |
---|
| 1522 | for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) { |
---|
| 1523 | Node m = _digraph->target(e); |
---|
| 1524 | if (!(*_reached)[m]) { |
---|
| 1525 | _visitor->discover(e); |
---|
| 1526 | _visitor->reach(m); |
---|
| 1527 | _reached->set(m, true); |
---|
| 1528 | _list[++_list_back] = m; |
---|
| 1529 | if (nm[m] && rnode == INVALID) rnode = m; |
---|
| 1530 | } else { |
---|
| 1531 | _visitor->examine(e); |
---|
| 1532 | } |
---|
| 1533 | } |
---|
| 1534 | return n; |
---|
| 1535 | } |
---|
| 1536 | |
---|
[244] | 1537 | /// \brief The next node to be processed. |
---|
[100] | 1538 | /// |
---|
[244] | 1539 | /// Returns the next node to be processed or \c INVALID if the queue |
---|
| 1540 | /// is empty. |
---|
| 1541 | Node nextNode() const { |
---|
[100] | 1542 | return _list_front != _list_back ? _list[_list_front + 1] : INVALID; |
---|
| 1543 | } |
---|
| 1544 | |
---|
| 1545 | /// \brief Returns \c false if there are nodes |
---|
[244] | 1546 | /// to be processed. |
---|
[100] | 1547 | /// |
---|
| 1548 | /// Returns \c false if there are nodes |
---|
[244] | 1549 | /// to be processed in the queue. |
---|
| 1550 | bool emptyQueue() const { return _list_front == _list_back; } |
---|
[100] | 1551 | |
---|
| 1552 | /// \brief Returns the number of the nodes to be processed. |
---|
| 1553 | /// |
---|
| 1554 | /// Returns the number of the nodes to be processed in the queue. |
---|
[244] | 1555 | int queueSize() const { return _list_back - _list_front; } |
---|
[209] | 1556 | |
---|
[100] | 1557 | /// \brief Executes the algorithm. |
---|
| 1558 | /// |
---|
| 1559 | /// Executes the algorithm. |
---|
| 1560 | /// |
---|
[244] | 1561 | /// This method runs the %BFS algorithm from the root node(s) |
---|
| 1562 | /// in order to compute the shortest path to each node. |
---|
| 1563 | /// |
---|
| 1564 | /// The algorithm computes |
---|
| 1565 | /// - the shortest path tree (forest), |
---|
| 1566 | /// - the distance of each node from the root(s). |
---|
| 1567 | /// |
---|
| 1568 | /// \pre init() must be called and at least one root node should be added |
---|
[100] | 1569 | /// with addSource() before using this function. |
---|
[244] | 1570 | /// |
---|
| 1571 | /// \note <tt>b.start()</tt> is just a shortcut of the following code. |
---|
| 1572 | /// \code |
---|
| 1573 | /// while ( !b.emptyQueue() ) { |
---|
| 1574 | /// b.processNextNode(); |
---|
| 1575 | /// } |
---|
| 1576 | /// \endcode |
---|
[100] | 1577 | void start() { |
---|
| 1578 | while ( !emptyQueue() ) processNextNode(); |
---|
| 1579 | } |
---|
[209] | 1580 | |
---|
[244] | 1581 | /// \brief Executes the algorithm until the given target node is reached. |
---|
[100] | 1582 | /// |
---|
[244] | 1583 | /// Executes the algorithm until the given target node is reached. |
---|
[100] | 1584 | /// |
---|
[244] | 1585 | /// This method runs the %BFS algorithm from the root node(s) |
---|
| 1586 | /// in order to compute the shortest path to \c dest. |
---|
| 1587 | /// |
---|
| 1588 | /// The algorithm computes |
---|
| 1589 | /// - the shortest path to \c dest, |
---|
| 1590 | /// - the distance of \c dest from the root(s). |
---|
| 1591 | /// |
---|
| 1592 | /// \pre init() must be called and at least one root node should be |
---|
| 1593 | /// added with addSource() before using this function. |
---|
| 1594 | /// |
---|
| 1595 | /// \note <tt>b.start(t)</tt> is just a shortcut of the following code. |
---|
| 1596 | /// \code |
---|
| 1597 | /// bool reach = false; |
---|
| 1598 | /// while ( !b.emptyQueue() && !reach ) { |
---|
| 1599 | /// b.processNextNode(t, reach); |
---|
| 1600 | /// } |
---|
| 1601 | /// \endcode |
---|
[100] | 1602 | void start(Node dest) { |
---|
| 1603 | bool reach = false; |
---|
| 1604 | while ( !emptyQueue() && !reach ) processNextNode(dest, reach); |
---|
| 1605 | } |
---|
[209] | 1606 | |
---|
[100] | 1607 | /// \brief Executes the algorithm until a condition is met. |
---|
| 1608 | /// |
---|
| 1609 | /// Executes the algorithm until a condition is met. |
---|
| 1610 | /// |
---|
[244] | 1611 | /// This method runs the %BFS algorithm from the root node(s) in |
---|
| 1612 | /// order to compute the shortest path to a node \c v with |
---|
| 1613 | /// <tt>nm[v]</tt> true, if such a node can be found. |
---|
[100] | 1614 | /// |
---|
[244] | 1615 | /// \param nm must be a bool (or convertible) node map. The |
---|
| 1616 | /// algorithm will stop when it reaches a node \c v with |
---|
[100] | 1617 | /// <tt>nm[v]</tt> true. |
---|
| 1618 | /// |
---|
[244] | 1619 | /// \return The reached node \c v with <tt>nm[v]</tt> true or |
---|
| 1620 | /// \c INVALID if no such node was found. |
---|
| 1621 | /// |
---|
| 1622 | /// \pre init() must be called and at least one root node should be |
---|
| 1623 | /// added with addSource() before using this function. |
---|
| 1624 | /// |
---|
| 1625 | /// \note <tt>b.start(nm)</tt> is just a shortcut of the following code. |
---|
| 1626 | /// \code |
---|
| 1627 | /// Node rnode = INVALID; |
---|
| 1628 | /// while ( !b.emptyQueue() && rnode == INVALID ) { |
---|
| 1629 | /// b.processNextNode(nm, rnode); |
---|
| 1630 | /// } |
---|
| 1631 | /// return rnode; |
---|
| 1632 | /// \endcode |
---|
[100] | 1633 | template <typename NM> |
---|
| 1634 | Node start(const NM &nm) { |
---|
| 1635 | Node rnode = INVALID; |
---|
| 1636 | while ( !emptyQueue() && rnode == INVALID ) { |
---|
[209] | 1637 | processNextNode(nm, rnode); |
---|
[100] | 1638 | } |
---|
| 1639 | return rnode; |
---|
| 1640 | } |
---|
| 1641 | |
---|
[244] | 1642 | /// \brief Runs the algorithm from the given node. |
---|
[100] | 1643 | /// |
---|
[244] | 1644 | /// This method runs the %BFS algorithm from node \c s |
---|
| 1645 | /// in order to compute the shortest path to each node. |
---|
| 1646 | /// |
---|
| 1647 | /// The algorithm computes |
---|
| 1648 | /// - the shortest path tree, |
---|
| 1649 | /// - the distance of each node from the root. |
---|
| 1650 | /// |
---|
| 1651 | /// \note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1652 | ///\code |
---|
| 1653 | /// b.init(); |
---|
| 1654 | /// b.addSource(s); |
---|
| 1655 | /// b.start(); |
---|
| 1656 | ///\endcode |
---|
| 1657 | void run(Node s) { |
---|
| 1658 | init(); |
---|
| 1659 | addSource(s); |
---|
| 1660 | start(); |
---|
| 1661 | } |
---|
| 1662 | |
---|
[244] | 1663 | /// \brief Runs the algorithm to visit all nodes in the digraph. |
---|
[209] | 1664 | /// |
---|
[100] | 1665 | /// This method runs the %BFS algorithm in order to |
---|
[244] | 1666 | /// compute the shortest path to each node. |
---|
[100] | 1667 | /// |
---|
[244] | 1668 | /// The algorithm computes |
---|
| 1669 | /// - the shortest path tree (forest), |
---|
| 1670 | /// - the distance of each node from the root(s). |
---|
| 1671 | /// |
---|
| 1672 | /// \note <tt>b.run(s)</tt> is just a shortcut of the following code. |
---|
[100] | 1673 | ///\code |
---|
| 1674 | /// b.init(); |
---|
[244] | 1675 | /// for (NodeIt n(gr); n != INVALID; ++n) { |
---|
| 1676 | /// if (!b.reached(n)) { |
---|
| 1677 | /// b.addSource(n); |
---|
[100] | 1678 | /// b.start(); |
---|
| 1679 | /// } |
---|
| 1680 | /// } |
---|
| 1681 | ///\endcode |
---|
| 1682 | void run() { |
---|
| 1683 | init(); |
---|
| 1684 | for (NodeIt it(*_digraph); it != INVALID; ++it) { |
---|
| 1685 | if (!reached(it)) { |
---|
| 1686 | addSource(it); |
---|
| 1687 | start(); |
---|
| 1688 | } |
---|
| 1689 | } |
---|
| 1690 | } |
---|
[244] | 1691 | |
---|
[100] | 1692 | ///@} |
---|
| 1693 | |
---|
| 1694 | /// \name Query Functions |
---|
| 1695 | /// The result of the %BFS algorithm can be obtained using these |
---|
| 1696 | /// functions.\n |
---|
[244] | 1697 | /// Either \ref lemon::BfsVisit::run() "run()" or |
---|
| 1698 | /// \ref lemon::BfsVisit::start() "start()" must be called before |
---|
| 1699 | /// using them. |
---|
[100] | 1700 | ///@{ |
---|
| 1701 | |
---|
[244] | 1702 | /// \brief Checks if a node is reachable from the root(s). |
---|
[100] | 1703 | /// |
---|
| 1704 | /// Returns \c true if \c v is reachable from the root(s). |
---|
| 1705 | /// \pre Either \ref run() or \ref start() |
---|
| 1706 | /// must be called before using this function. |
---|
| 1707 | bool reached(Node v) { return (*_reached)[v]; } |
---|
[244] | 1708 | |
---|
[100] | 1709 | ///@} |
---|
[244] | 1710 | |
---|
[100] | 1711 | }; |
---|
| 1712 | |
---|
| 1713 | } //END OF NAMESPACE LEMON |
---|
| 1714 | |
---|
| 1715 | #endif |
---|