COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/dfs.h @ 1284:b941d044f87b

Last change on this file since 1284:b941d044f87b was 1283:fc20371677b9, checked in by Alpar Juttner, 15 years ago

getPath() added to Bfs/Dfs/Dijkstra?.

File size: 34.8 KB
Line 
1/* -*- C++ -*-
2 * src/lemon/dfs.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, EGRES).
6 *
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
10 *
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
13 * purpose.
14 *
15 */
16
17#ifndef LEMON_DFS_H
18#define LEMON_DFS_H
19
20///\ingroup flowalgs
21///\file
22///\brief Dfs algorithm.
23
24#include <lemon/list_graph.h>
25#include <lemon/graph_utils.h>
26#include <lemon/invalid.h>
27#include <lemon/error.h>
28#include <lemon/maps.h>
29
30namespace lemon {
31
32
33 
34  ///Default traits class of Dfs class.
35
36  ///Default traits class of Dfs class.
37  ///\param GR Graph type.
38  template<class GR>
39  struct DfsDefaultTraits
40  {
41    ///The graph type the algorithm runs on.
42    typedef GR Graph;
43    ///\brief The type of the map that stores the last
44    ///edges of the %DFS paths.
45    ///
46    ///The type of the map that stores the last
47    ///edges of the %DFS paths.
48    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
49    ///
50    typedef typename Graph::template NodeMap<typename GR::Edge> PredMap;
51    ///Instantiates a PredMap.
52 
53    ///This function instantiates a \ref PredMap.
54    ///\param G is the graph, to which we would like to define the PredMap.
55    ///\todo The graph alone may be insufficient to initialize
56    static PredMap *createPredMap(const GR &G)
57    {
58      return new PredMap(G);
59    }
60//     ///\brief The type of the map that stores the last but one
61//     ///nodes of the %DFS paths.
62//     ///
63//     ///The type of the map that stores the last but one
64//     ///nodes of the %DFS paths.
65//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
66//     ///
67//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
68//     ///Instantiates a PredNodeMap.
69   
70//     ///This function instantiates a \ref PredNodeMap.
71//     ///\param G is the graph, to which
72//     ///we would like to define the \ref PredNodeMap
73//     static PredNodeMap *createPredNodeMap(const GR &G)
74//     {
75//       return new PredNodeMap();
76//     }
77
78    ///The type of the map that indicates which nodes are processed.
79 
80    ///The type of the map that indicates which nodes are processed.
81    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
82    ///\todo named parameter to set this type, function to read and write.
83    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
84    ///Instantiates a ProcessedMap.
85 
86    ///This function instantiates a \ref ProcessedMap.
87    ///\param G is the graph, to which
88    ///we would like to define the \ref ProcessedMap
89    static ProcessedMap *createProcessedMap(const GR &G)
90    {
91      return new ProcessedMap();
92    }
93    ///The type of the map that indicates which nodes are reached.
94 
95    ///The type of the map that indicates which nodes are reached.
96    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
97    ///\todo named parameter to set this type, function to read and write.
98    typedef typename Graph::template NodeMap<bool> ReachedMap;
99    ///Instantiates a ReachedMap.
100 
101    ///This function instantiates a \ref ReachedMap.
102    ///\param G is the graph, to which
103    ///we would like to define the \ref ReachedMap.
104    static ReachedMap *createReachedMap(const GR &G)
105    {
106      return new ReachedMap(G);
107    }
108    ///The type of the map that stores the dists of the nodes.
109 
110    ///The type of the map that stores the dists of the nodes.
111    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
112    ///
113    typedef typename Graph::template NodeMap<int> DistMap;
114    ///Instantiates a DistMap.
115 
116    ///This function instantiates a \ref DistMap.
117    ///\param G is the graph, to which we would like to define the \ref DistMap
118    static DistMap *createDistMap(const GR &G)
119    {
120      return new DistMap(G);
121    }
122  };
123 
124  ///%DFS algorithm class.
125 
126  ///\ingroup flowalgs
127  ///This class provides an efficient implementation of the %DFS algorithm.
128  ///
129  ///\param GR The graph type the algorithm runs on. The default value is
130  ///\ref ListGraph. The value of GR is not used directly by Dfs, it
131  ///is only passed to \ref DfsDefaultTraits.
132  ///\param TR Traits class to set various data types used by the algorithm.
133  ///The default traits class is
134  ///\ref DfsDefaultTraits "DfsDefaultTraits<GR>".
135  ///See \ref DfsDefaultTraits for the documentation of
136  ///a Dfs traits class.
137  ///
138  ///\author Jacint Szabo and Alpar Juttner
139  ///\todo A compare object would be nice.
140
141#ifdef DOXYGEN
142  template <typename GR,
143            typename TR>
144#else
145  template <typename GR=ListGraph,
146            typename TR=DfsDefaultTraits<GR> >
147#endif
148  class Dfs {
149  public:
150    /**
151     * \brief \ref Exception for uninitialized parameters.
152     *
153     * This error represents problems in the initialization
154     * of the parameters of the algorithms.
155     */
156    class UninitializedParameter : public lemon::UninitializedParameter {
157    public:
158      virtual const char* exceptionName() const {
159        return "lemon::Dfs::UninitializedParameter";
160      }
161    };
162
163    typedef TR Traits;
164    ///The type of the underlying graph.
165    typedef typename TR::Graph Graph;
166    ///\e
167    typedef typename Graph::Node Node;
168    ///\e
169    typedef typename Graph::NodeIt NodeIt;
170    ///\e
171    typedef typename Graph::Edge Edge;
172    ///\e
173    typedef typename Graph::OutEdgeIt OutEdgeIt;
174   
175    ///\brief The type of the map that stores the last
176    ///edges of the %DFS paths.
177    typedef typename TR::PredMap PredMap;
178//     ///\brief The type of the map that stores the last but one
179//     ///nodes of the %DFS paths.
180//     typedef typename TR::PredNodeMap PredNodeMap;
181    ///The type of the map indicating which nodes are reached.
182    typedef typename TR::ReachedMap ReachedMap;
183    ///The type of the map indicating which nodes are processed.
184    typedef typename TR::ProcessedMap ProcessedMap;
185    ///The type of the map that stores the dists of the nodes.
186    typedef typename TR::DistMap DistMap;
187  private:
188    /// Pointer to the underlying graph.
189    const Graph *G;
190    ///Pointer to the map of predecessors edges.
191    PredMap *_pred;
192    ///Indicates if \ref _pred is locally allocated (\c true) or not.
193    bool local_pred;
194//     ///Pointer to the map of predecessors nodes.
195//     PredNodeMap *_predNode;
196//     ///Indicates if \ref _predNode is locally allocated (\c true) or not.
197//     bool local_predNode;
198    ///Pointer to the map of distances.
199    DistMap *_dist;
200    ///Indicates if \ref _dist is locally allocated (\c true) or not.
201    bool local_dist;
202    ///Pointer to the map of reached status of the nodes.
203    ReachedMap *_reached;
204    ///Indicates if \ref _reached is locally allocated (\c true) or not.
205    bool local_reached;
206    ///Pointer to the map of processed status of the nodes.
207    ProcessedMap *_processed;
208    ///Indicates if \ref _processed is locally allocated (\c true) or not.
209    bool local_processed;
210
211    std::vector<typename Graph::OutEdgeIt> _stack;
212    int _stack_head;
213//     ///The source node of the last execution.
214//     Node source;
215
216    ///Creates the maps if necessary.
217   
218    ///\todo Error if \c G are \c NULL.
219    ///\todo Better memory allocation (instead of new).
220    void create_maps()
221    {
222      if(!_pred) {
223        local_pred = true;
224        _pred = Traits::createPredMap(*G);
225      }
226//       if(!_predNode) {
227//      local_predNode = true;
228//      _predNode = Traits::createPredNodeMap(*G);
229//       }
230      if(!_dist) {
231        local_dist = true;
232        _dist = Traits::createDistMap(*G);
233      }
234      if(!_reached) {
235        local_reached = true;
236        _reached = Traits::createReachedMap(*G);
237      }
238      if(!_processed) {
239        local_processed = true;
240        _processed = Traits::createProcessedMap(*G);
241      }
242    }
243   
244  public :
245 
246    ///\name Named template parameters
247
248    ///@{
249
250    template <class T>
251    struct DefPredMapTraits : public Traits {
252      typedef T PredMap;
253      static PredMap *createPredMap(const Graph &G)
254      {
255        throw UninitializedParameter();
256      }
257    };
258    ///\ref named-templ-param "Named parameter" for setting PredMap type
259
260    ///\ref named-templ-param "Named parameter" for setting PredMap type
261    ///
262    template <class T>
263    class DefPredMap : public Dfs< Graph,
264                                        DefPredMapTraits<T> > { };
265   
266//     template <class T>
267//     struct DefPredNodeMapTraits : public Traits {
268//       typedef T PredNodeMap;
269//       static PredNodeMap *createPredNodeMap(const Graph &G)
270//       {
271//      throw UninitializedParameter();
272//       }
273//     };
274//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
275
276//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
277//     ///
278//     template <class T>
279//     class DefPredNodeMap : public Dfs< Graph,
280//                                          LengthMap,
281//                                          DefPredNodeMapTraits<T> > { };
282   
283    template <class T>
284    struct DefDistMapTraits : public Traits {
285      typedef T DistMap;
286      static DistMap *createDistMap(const Graph &G)
287      {
288        throw UninitializedParameter();
289      }
290    };
291    ///\ref named-templ-param "Named parameter" for setting DistMap type
292
293    ///\ref named-templ-param "Named parameter" for setting DistMap type
294    ///
295    template <class T>
296    class DefDistMap : public Dfs< Graph,
297                                   DefDistMapTraits<T> > { };
298   
299    template <class T>
300    struct DefReachedMapTraits : public Traits {
301      typedef T ReachedMap;
302      static ReachedMap *createReachedMap(const Graph &G)
303      {
304        throw UninitializedParameter();
305      }
306    };
307    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
308
309    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
310    ///
311    template <class T>
312    class DefReachedMap : public Dfs< Graph,
313                                      DefReachedMapTraits<T> > { };
314   
315    struct DefGraphReachedMapTraits : public Traits {
316      typedef typename Graph::template NodeMap<bool> ReachedMap;
317      static ReachedMap *createReachedMap(const Graph &G)
318      {
319        return new ReachedMap(G);
320      }
321    };
322    template <class T>
323    struct DefProcessedMapTraits : public Traits {
324      typedef T ProcessedMap;
325      static ProcessedMap *createProcessedMap(const Graph &G)
326      {
327        throw UninitializedParameter();
328      }
329    };
330    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
331
332    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
333    ///
334    template <class T>
335    class DefProcessedMap : public Dfs< Graph,
336                                        DefProcessedMapTraits<T> > { };
337   
338    struct DefGraphProcessedMapTraits : public Traits {
339      typedef typename Graph::template NodeMap<bool> ProcessedMap;
340      static ProcessedMap *createProcessedMap(const Graph &G)
341      {
342        return new ProcessedMap(G);
343      }
344    };
345    ///\brief \ref named-templ-param "Named parameter"
346    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
347    ///
348    ///\ref named-templ-param "Named parameter"
349    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
350    ///If you don't set it explicitely, it will be automatically allocated.
351    template <class T>
352    class DefProcessedMapToBeDefaultMap :
353      public Dfs< Graph,
354                  DefGraphProcessedMapTraits> { };
355   
356    ///@}
357
358  public:     
359   
360    ///Constructor.
361   
362    ///\param _G the graph the algorithm will run on.
363    ///
364    Dfs(const Graph& _G) :
365      G(&_G),
366      _pred(NULL), local_pred(false),
367//       _predNode(NULL), local_predNode(false),
368      _dist(NULL), local_dist(false),
369      _reached(NULL), local_reached(false),
370      _processed(NULL), local_processed(false)
371    { }
372   
373    ///Destructor.
374    ~Dfs()
375    {
376      if(local_pred) delete _pred;
377//       if(local_predNode) delete _predNode;
378      if(local_dist) delete _dist;
379      if(local_reached) delete _reached;
380      if(local_processed) delete _processed;
381    }
382
383    ///Sets the map storing the predecessor edges.
384
385    ///Sets the map storing the predecessor edges.
386    ///If you don't use this function before calling \ref run(),
387    ///it will allocate one. The destuctor deallocates this
388    ///automatically allocated map, of course.
389    ///\return <tt> (*this) </tt>
390    Dfs &predMap(PredMap &m)
391    {
392      if(local_pred) {
393        delete _pred;
394        local_pred=false;
395      }
396      _pred = &m;
397      return *this;
398    }
399
400//     ///Sets the map storing the predecessor nodes.
401
402//     ///Sets the map storing the predecessor nodes.
403//     ///If you don't use this function before calling \ref run(),
404//     ///it will allocate one. The destuctor deallocates this
405//     ///automatically allocated map, of course.
406//     ///\return <tt> (*this) </tt>
407//     Dfs &predNodeMap(PredNodeMap &m)
408//     {
409//       if(local_predNode) {
410//      delete _predNode;
411//      local_predNode=false;
412//       }
413//       _predNode = &m;
414//       return *this;
415//     }
416
417    ///Sets the map storing the distances calculated by the algorithm.
418
419    ///Sets the map storing the distances calculated by the algorithm.
420    ///If you don't use this function before calling \ref run(),
421    ///it will allocate one. The destuctor deallocates this
422    ///automatically allocated map, of course.
423    ///\return <tt> (*this) </tt>
424    Dfs &distMap(DistMap &m)
425    {
426      if(local_dist) {
427        delete _dist;
428        local_dist=false;
429      }
430      _dist = &m;
431      return *this;
432    }
433
434    ///Sets the map indicating if a node is reached.
435
436    ///Sets the map indicating if a node is reached.
437    ///If you don't use this function before calling \ref run(),
438    ///it will allocate one. The destuctor deallocates this
439    ///automatically allocated map, of course.
440    ///\return <tt> (*this) </tt>
441    Dfs &reachedMap(ReachedMap &m)
442    {
443      if(local_reached) {
444        delete _reached;
445        local_reached=false;
446      }
447      _reached = &m;
448      return *this;
449    }
450
451    ///Sets the map indicating if a node is processed.
452
453    ///Sets the map indicating if a node is processed.
454    ///If you don't use this function before calling \ref run(),
455    ///it will allocate one. The destuctor deallocates this
456    ///automatically allocated map, of course.
457    ///\return <tt> (*this) </tt>
458    Dfs &processedMap(ProcessedMap &m)
459    {
460      if(local_processed) {
461        delete _processed;
462        local_processed=false;
463      }
464      _processed = &m;
465      return *this;
466    }
467
468  public:
469    ///\name Execution control
470    ///The simplest way to execute the algorithm is to use
471    ///one of the member functions called \c run(...).
472    ///\n
473    ///If you need more control on the execution,
474    ///first you must call \ref init(), then you can add several source nodes
475    ///with \ref addSource().
476    ///Finally \ref start() will perform the actual path
477    ///computation.
478
479    ///@{
480
481    ///Initializes the internal data structures.
482
483    ///Initializes the internal data structures.
484    ///
485    void init()
486    {
487      create_maps();
488      _stack.resize(countNodes(*G));
489      _stack_head=-1;
490      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
491        _pred->set(u,INVALID);
492        // _predNode->set(u,INVALID);
493        _reached->set(u,false);
494        _processed->set(u,false);
495      }
496    }
497   
498    ///Adds a new source node.
499
500    ///Adds a new source node to the set of nodes to be processed.
501    ///
502    ///\bug dist's are wrong (or at least strange) in case of multiple sources.
503    void addSource(Node s)
504    {
505      if(!(*_reached)[s])
506        {
507          _reached->set(s,true);
508          _pred->set(s,INVALID);
509          // _predNode->set(u,INVALID);
510          _stack[++_stack_head]=OutEdgeIt(*G,s);
511          _dist->set(s,_stack_head);
512        }
513    }
514   
515    ///Processes the next node.
516
517    ///Processes the next node.
518    ///
519    ///\warning The stack must not be empty!
520    void processNextEdge()
521    {
522      Node m;
523      Edge e=_stack[_stack_head];
524      if(!(*_reached)[m=G->target(e)]) {
525        _pred->set(m,e);
526        _reached->set(m,true);
527        //        _pred_node->set(m,G->source(e));
528        ++_stack_head;
529        _stack[_stack_head] = OutEdgeIt(*G, m);
530        _dist->set(m,_stack_head);
531      }
532      else {
533        Node n;
534        while(_stack_head>=0 &&
535              (n=G->source(_stack[_stack_head]),
536               ++_stack[_stack_head]==INVALID))
537          {
538            _processed->set(n,true);
539            --_stack_head;
540          }
541      }
542    }
543     
544    ///\brief Returns \c false if there are nodes
545    ///to be processed in the queue
546    ///
547    ///Returns \c false if there are nodes
548    ///to be processed in the queue
549    bool emptyQueue() { return _stack_head<0; }
550    ///Returns the number of the nodes to be processed.
551   
552    ///Returns the number of the nodes to be processed in the queue.
553    ///
554    int queueSize() { return _stack_head+1; }
555   
556    ///Executes the algorithm.
557
558    ///Executes the algorithm.
559    ///
560    ///\pre init() must be called and at least one node should be added
561    ///with addSource() before using this function.
562    ///
563    ///This method runs the %DFS algorithm from the root node(s)
564    ///in order to
565    ///compute the
566    ///%DFS path to each node. The algorithm computes
567    ///- The %DFS tree.
568    ///- The distance of each node from the root(s).
569    ///
570    void start()
571    {
572      while ( !emptyQueue() ) processNextEdge();
573    }
574   
575    ///Executes the algorithm until \c dest is reached.
576
577    ///Executes the algorithm until \c dest is reached.
578    ///
579    ///\pre init() must be called and at least one node should be added
580    ///with addSource() before using this function.
581    ///
582    ///This method runs the %DFS algorithm from the root node(s)
583    ///in order to
584    ///compute the
585    ///%DFS path to \c dest. The algorithm computes
586    ///- The %DFS path to \c  dest.
587    ///- The distance of \c dest from the root(s).
588    ///
589    void start(Node dest)
590    {
591      while ( !emptyQueue() && G->target(_stack[_stack_head])!=dest )
592        processNextEdge();
593    }
594   
595    ///Executes the algorithm until a condition is met.
596
597    ///Executes the algorithm until a condition is met.
598    ///
599    ///\pre init() must be called and at least one node should be added
600    ///with addSource() before using this function.
601    ///
602    ///\param nm must be a bool (or convertible) edge map. The algorithm
603    ///will stop when it reaches a edge \c v with <tt>nm[v]==true</tt>.
604    ///\warning Contrary to \ref Dfs and \ref Dijkstra, \c mn is an edge map,
605    ///not a node map.
606    template<class NM>
607      void start(const NM &nm)
608      {
609        while ( !emptyQueue() && !nm[_stack[_stack_head]] ) processNextEdge();
610      }
611   
612    ///Runs %DFS algorithm from node \c s.
613   
614    ///This method runs the %DFS algorithm from a root node \c s
615    ///in order to
616    ///compute the
617    ///%DFS path to each node. The algorithm computes
618    ///- The %DFS tree.
619    ///- The distance of each node from the root.
620    ///
621    ///\note d.run(s) is just a shortcut of the following code.
622    ///\code
623    ///  d.init();
624    ///  d.addSource(s);
625    ///  d.start();
626    ///\endcode
627    void run(Node s) {
628      init();
629      addSource(s);
630      start();
631    }
632   
633    ///Finds the %DFS path between \c s and \c t.
634   
635    ///Finds the %DFS path between \c s and \c t.
636    ///
637    ///\return The length of the %DFS s---t path if there exists one,
638    ///0 otherwise.
639    ///\note Apart from the return value, d.run(s) is
640    ///just a shortcut of the following code.
641    ///\code
642    ///  d.init();
643    ///  d.addSource(s);
644    ///  d.start(t);
645    ///\endcode
646    int run(Node s,Node t) {
647      init();
648      addSource(s);
649      start(t);
650      return reached(t)?_stack_head+1:0;
651    }
652   
653    ///@}
654
655    ///\name Query Functions
656    ///The result of the %DFS algorithm can be obtained using these
657    ///functions.\n
658    ///Before the use of these functions,
659    ///either run() or start() must be called.
660   
661    ///@{
662
663    ///Copies the path to \c t on the DFS tree into \c p
664   
665    ///This function copies the path on the DFS tree to \c t into \c p.
666    ///If it \c \t is a source itself or unreachable, then it does not
667    ///alter \c p.
668    ///\todo Is it the right way to handle unreachable nodes?
669    ///\return Returns \c true if a path to \c t was actually copied to \c p,
670    ///\c false otherwise.
671    ///\sa DirPath
672    template<class P>
673    bool getPath(P &p,Node t)
674    {
675      if(reached(t)) {
676        p.clear();
677        typename P::Builder b(p);
678        for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t))
679          b.pushFront(pred(t));
680        b.commit();
681        return true;
682      }
683      return false;
684    }
685
686    ///The distance of a node from the root(s).
687
688    ///Returns the distance of a node from the root(s).
689    ///\pre \ref run() must be called before using this function.
690    ///\warning If node \c v in unreachable from the root(s) the return value
691    ///of this funcion is undefined.
692    int dist(Node v) const { return (*_dist)[v]; }
693
694    ///Returns the 'previous edge' of the %DFS tree.
695
696    ///For a node \c v it returns the 'previous edge'
697    ///of the %DFS path,
698    ///i.e. it returns the last edge of a %DFS path from the root(s) to \c
699    ///v. It is \ref INVALID
700    ///if \c v is unreachable from the root(s) or \c v is a root. The
701    ///%DFS tree used here is equal to the %DFS tree used in
702    ///\ref predNode(Node v).
703    ///\pre Either \ref run() or \ref start() must be called before using
704    ///this function.
705    ///\todo predEdge could be a better name.
706    Edge pred(Node v) const { return (*_pred)[v];}
707
708    ///Returns the 'previous node' of the %DFS tree.
709
710    ///For a node \c v it returns the 'previous node'
711    ///of the %DFS tree,
712    ///i.e. it returns the last but one node from a %DFS path from the
713    ///root(a) to \c /v.
714    ///It is INVALID if \c v is unreachable from the root(s) or
715    ///if \c v itself a root.
716    ///The %DFS tree used here is equal to the %DFS
717    ///tree used in \ref pred(Node v).
718    ///\pre Either \ref run() or \ref start() must be called before
719    ///using this function.
720    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
721                                  G->source((*_pred)[v]); }
722   
723    ///Returns a reference to the NodeMap of distances.
724
725    ///Returns a reference to the NodeMap of distances.
726    ///\pre Either \ref run() or \ref init() must
727    ///be called before using this function.
728    const DistMap &distMap() const { return *_dist;}
729 
730    ///Returns a reference to the %DFS edge-tree map.
731
732    ///Returns a reference to the NodeMap of the edges of the
733    ///%DFS tree.
734    ///\pre Either \ref run() or \ref init()
735    ///must be called before using this function.
736    const PredMap &predMap() const { return *_pred;}
737 
738//     ///Returns a reference to the map of nodes of %DFS paths.
739
740//     ///Returns a reference to the NodeMap of the last but one nodes of the
741//     ///%DFS tree.
742//     ///\pre \ref run() must be called before using this function.
743//     const PredNodeMap &predNodeMap() const { return *_predNode;}
744
745    ///Checks if a node is reachable from the root.
746
747    ///Returns \c true if \c v is reachable from the root.
748    ///\warning The source nodes are inditated as unreached.
749    ///\pre Either \ref run() or \ref start()
750    ///must be called before using this function.
751    ///
752    bool reached(Node v) { return (*_reached)[v]; }
753   
754    ///@}
755  };
756
757  ///Default traits class of Dfs function.
758
759  ///Default traits class of Dfs function.
760  ///\param GR Graph type.
761  template<class GR>
762  struct DfsWizardDefaultTraits
763  {
764    ///The graph type the algorithm runs on.
765    typedef GR Graph;
766    ///\brief The type of the map that stores the last
767    ///edges of the %DFS paths.
768    ///
769    ///The type of the map that stores the last
770    ///edges of the %DFS paths.
771    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
772    ///
773    typedef NullMap<typename Graph::Node,typename GR::Edge> PredMap;
774    ///Instantiates a PredMap.
775 
776    ///This function instantiates a \ref PredMap.
777    ///\param G is the graph, to which we would like to define the PredMap.
778    ///\todo The graph alone may be insufficient to initialize
779    static PredMap *createPredMap(const GR &G)
780    {
781      return new PredMap();
782    }
783//     ///\brief The type of the map that stores the last but one
784//     ///nodes of the %DFS paths.
785//     ///
786//     ///The type of the map that stores the last but one
787//     ///nodes of the %DFS paths.
788//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
789//     ///
790//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
791//     ///Instantiates a PredNodeMap.
792   
793//     ///This function instantiates a \ref PredNodeMap.
794//     ///\param G is the graph, to which
795//     ///we would like to define the \ref PredNodeMap
796//     static PredNodeMap *createPredNodeMap(const GR &G)
797//     {
798//       return new PredNodeMap();
799//     }
800
801    ///The type of the map that indicates which nodes are processed.
802 
803    ///The type of the map that indicates which nodes are processed.
804    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
805    ///\todo named parameter to set this type, function to read and write.
806    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
807    ///Instantiates a ProcessedMap.
808 
809    ///This function instantiates a \ref ProcessedMap.
810    ///\param G is the graph, to which
811    ///we would like to define the \ref ProcessedMap
812    static ProcessedMap *createProcessedMap(const GR &G)
813    {
814      return new ProcessedMap();
815    }
816    ///The type of the map that indicates which nodes are reached.
817 
818    ///The type of the map that indicates which nodes are reached.
819    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
820    ///\todo named parameter to set this type, function to read and write.
821    typedef typename Graph::template NodeMap<bool> ReachedMap;
822    ///Instantiates a ReachedMap.
823 
824    ///This function instantiates a \ref ReachedMap.
825    ///\param G is the graph, to which
826    ///we would like to define the \ref ReachedMap.
827    static ReachedMap *createReachedMap(const GR &G)
828    {
829      return new ReachedMap(G);
830    }
831    ///The type of the map that stores the dists of the nodes.
832 
833    ///The type of the map that stores the dists of the nodes.
834    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
835    ///
836    typedef NullMap<typename Graph::Node,int> DistMap;
837    ///Instantiates a DistMap.
838 
839    ///This function instantiates a \ref DistMap.
840    ///\param G is the graph, to which we would like to define the \ref DistMap
841    static DistMap *createDistMap(const GR &G)
842    {
843      return new DistMap();
844    }
845  };
846 
847  /// Default traits used by \ref DfsWizard
848
849  /// To make it easier to use Dfs algorithm
850  ///we have created a wizard class.
851  /// This \ref DfsWizard class needs default traits,
852  ///as well as the \ref Dfs class.
853  /// The \ref DfsWizardBase is a class to be the default traits of the
854  /// \ref DfsWizard class.
855  template<class GR>
856  class DfsWizardBase : public DfsWizardDefaultTraits<GR>
857  {
858
859    typedef DfsWizardDefaultTraits<GR> Base;
860  protected:
861    /// Type of the nodes in the graph.
862    typedef typename Base::Graph::Node Node;
863
864    /// Pointer to the underlying graph.
865    void *_g;
866    ///Pointer to the map of reached nodes.
867    void *_reached;
868    ///Pointer to the map of processed nodes.
869    void *_processed;
870    ///Pointer to the map of predecessors edges.
871    void *_pred;
872//     ///Pointer to the map of predecessors nodes.
873//     void *_predNode;
874    ///Pointer to the map of distances.
875    void *_dist;
876    ///Pointer to the source node.
877    Node _source;
878   
879    public:
880    /// Constructor.
881   
882    /// This constructor does not require parameters, therefore it initiates
883    /// all of the attributes to default values (0, INVALID).
884    DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0),
885//                         _predNode(0),
886                           _dist(0), _source(INVALID) {}
887
888    /// Constructor.
889   
890    /// This constructor requires some parameters,
891    /// listed in the parameters list.
892    /// Others are initiated to 0.
893    /// \param g is the initial value of  \ref _g
894    /// \param s is the initial value of  \ref _source
895    DfsWizardBase(const GR &g, Node s=INVALID) :
896      _g((void *)&g), _reached(0), _processed(0), _pred(0),
897//       _predNode(0),
898      _dist(0), _source(s) {}
899
900  };
901 
902  /// A class to make the usage of Dfs algorithm easier
903
904  /// This class is created to make it easier to use Dfs algorithm.
905  /// It uses the functions and features of the plain \ref Dfs,
906  /// but it is much simpler to use it.
907  ///
908  /// Simplicity means that the way to change the types defined
909  /// in the traits class is based on functions that returns the new class
910  /// and not on templatable built-in classes.
911  /// When using the plain \ref Dfs
912  /// the new class with the modified type comes from
913  /// the original class by using the ::
914  /// operator. In the case of \ref DfsWizard only
915  /// a function have to be called and it will
916  /// return the needed class.
917  ///
918  /// It does not have own \ref run method. When its \ref run method is called
919  /// it initiates a plain \ref Dfs class, and calls the \ref Dfs::run
920  /// method of it.
921  template<class TR>
922  class DfsWizard : public TR
923  {
924    typedef TR Base;
925
926    ///The type of the underlying graph.
927    typedef typename TR::Graph Graph;
928    //\e
929    typedef typename Graph::Node Node;
930    //\e
931    typedef typename Graph::NodeIt NodeIt;
932    //\e
933    typedef typename Graph::Edge Edge;
934    //\e
935    typedef typename Graph::OutEdgeIt OutEdgeIt;
936   
937    ///\brief The type of the map that stores
938    ///the reached nodes
939    typedef typename TR::ReachedMap ReachedMap;
940    ///\brief The type of the map that stores
941    ///the processed nodes
942    typedef typename TR::ProcessedMap ProcessedMap;
943    ///\brief The type of the map that stores the last
944    ///edges of the %DFS paths.
945    typedef typename TR::PredMap PredMap;
946//     ///\brief The type of the map that stores the last but one
947//     ///nodes of the %DFS paths.
948//     typedef typename TR::PredNodeMap PredNodeMap;
949    ///The type of the map that stores the dists of the nodes.
950    typedef typename TR::DistMap DistMap;
951
952public:
953    /// Constructor.
954    DfsWizard() : TR() {}
955
956    /// Constructor that requires parameters.
957
958    /// Constructor that requires parameters.
959    /// These parameters will be the default values for the traits class.
960    DfsWizard(const Graph &g, Node s=INVALID) :
961      TR(g,s) {}
962
963    ///Copy constructor
964    DfsWizard(const TR &b) : TR(b) {}
965
966    ~DfsWizard() {}
967
968    ///Runs Dfs algorithm from a given node.
969   
970    ///Runs Dfs algorithm from a given node.
971    ///The node can be given by the \ref source function.
972    void run()
973    {
974      if(Base::_source==INVALID) throw UninitializedParameter();
975      Dfs<Graph,TR> alg(*(Graph*)Base::_g);
976      if(Base::_reached) alg.reachedMap(*(ReachedMap*)Base::_reached);
977      if(Base::_processed) alg.processedMap(*(ProcessedMap*)Base::_processed);
978      if(Base::_pred) alg.predMap(*(PredMap*)Base::_pred);
979//       if(Base::_predNode) alg.predNodeMap(*(PredNodeMap*)Base::_predNode);
980      if(Base::_dist) alg.distMap(*(DistMap*)Base::_dist);
981      alg.run(Base::_source);
982    }
983
984    ///Runs Dfs algorithm from the given node.
985
986    ///Runs Dfs algorithm from the given node.
987    ///\param s is the given source.
988    void run(Node s)
989    {
990      Base::_source=s;
991      run();
992    }
993
994    template<class T>
995    struct DefPredMapBase : public Base {
996      typedef T PredMap;
997      static PredMap *createPredMap(const Graph &G) { return 0; };
998      DefPredMapBase(const TR &b) : TR(b) {}
999    };
1000   
1001    ///\brief \ref named-templ-param "Named parameter"
1002    ///function for setting PredMap type
1003    ///
1004    /// \ref named-templ-param "Named parameter"
1005    ///function for setting PredMap type
1006    ///
1007    template<class T>
1008    DfsWizard<DefPredMapBase<T> > predMap(const T &t)
1009    {
1010      Base::_pred=(void *)&t;
1011      return DfsWizard<DefPredMapBase<T> >(*this);
1012    }
1013   
1014 
1015    template<class T>
1016    struct DefReachedMapBase : public Base {
1017      typedef T ReachedMap;
1018      static ReachedMap *createReachedMap(const Graph &G) { return 0; };
1019      DefReachedMapBase(const TR &b) : TR(b) {}
1020    };
1021   
1022    ///\brief \ref named-templ-param "Named parameter"
1023    ///function for setting ReachedMap
1024    ///
1025    /// \ref named-templ-param "Named parameter"
1026    ///function for setting ReachedMap
1027    ///
1028    template<class T>
1029    DfsWizard<DefReachedMapBase<T> > reachedMap(const T &t)
1030    {
1031      Base::_pred=(void *)&t;
1032      return DfsWizard<DefReachedMapBase<T> >(*this);
1033    }
1034   
1035
1036    template<class T>
1037    struct DefProcessedMapBase : public Base {
1038      typedef T ProcessedMap;
1039      static ProcessedMap *createProcessedMap(const Graph &G) { return 0; };
1040      DefProcessedMapBase(const TR &b) : TR(b) {}
1041    };
1042   
1043    ///\brief \ref named-templ-param "Named parameter"
1044    ///function for setting ProcessedMap
1045    ///
1046    /// \ref named-templ-param "Named parameter"
1047    ///function for setting ProcessedMap
1048    ///
1049    template<class T>
1050    DfsWizard<DefProcessedMapBase<T> > processedMap(const T &t)
1051    {
1052      Base::_pred=(void *)&t;
1053      return DfsWizard<DefProcessedMapBase<T> >(*this);
1054    }
1055   
1056
1057//     template<class T>
1058//     struct DefPredNodeMapBase : public Base {
1059//       typedef T PredNodeMap;
1060//       static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
1061//       DefPredNodeMapBase(const TR &b) : TR(b) {}
1062//     };
1063   
1064//     ///\brief \ref named-templ-param "Named parameter"
1065//     ///function for setting PredNodeMap type
1066//     ///
1067//     /// \ref named-templ-param "Named parameter"
1068//     ///function for setting PredNodeMap type
1069//     ///
1070//     template<class T>
1071//     DfsWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
1072//     {
1073//       Base::_predNode=(void *)&t;
1074//       return DfsWizard<DefPredNodeMapBase<T> >(*this);
1075//     }
1076   
1077    template<class T>
1078    struct DefDistMapBase : public Base {
1079      typedef T DistMap;
1080      static DistMap *createDistMap(const Graph &G) { return 0; };
1081      DefDistMapBase(const TR &b) : TR(b) {}
1082    };
1083   
1084    ///\brief \ref named-templ-param "Named parameter"
1085    ///function for setting DistMap type
1086    ///
1087    /// \ref named-templ-param "Named parameter"
1088    ///function for setting DistMap type
1089    ///
1090    template<class T>
1091    DfsWizard<DefDistMapBase<T> > distMap(const T &t)
1092    {
1093      Base::_dist=(void *)&t;
1094      return DfsWizard<DefDistMapBase<T> >(*this);
1095    }
1096   
1097    /// Sets the source node, from which the Dfs algorithm runs.
1098
1099    /// Sets the source node, from which the Dfs algorithm runs.
1100    /// \param s is the source node.
1101    DfsWizard<TR> &source(Node s)
1102    {
1103      Base::_source=s;
1104      return *this;
1105    }
1106   
1107  };
1108 
1109  ///Function type interface for Dfs algorithm.
1110
1111  /// \ingroup flowalgs
1112  ///Function type interface for Dfs algorithm.
1113  ///
1114  ///This function also has several
1115  ///\ref named-templ-func-param "named parameters",
1116  ///they are declared as the members of class \ref DfsWizard.
1117  ///The following
1118  ///example shows how to use these parameters.
1119  ///\code
1120  ///  dfs(g,source).predMap(preds).run();
1121  ///\endcode
1122  ///\warning Don't forget to put the \ref DfsWizard::run() "run()"
1123  ///to the end of the parameter list.
1124  ///\sa DfsWizard
1125  ///\sa Dfs
1126  template<class GR>
1127  DfsWizard<DfsWizardBase<GR> >
1128  dfs(const GR &g,typename GR::Node s=INVALID)
1129  {
1130    return DfsWizard<DfsWizardBase<GR> >(g,s);
1131  }
1132
1133} //END OF NAMESPACE LEMON
1134
1135#endif
1136
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