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