COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/dfs.h @ 1622:9c98841eda96

Last change on this file since 1622:9c98841eda96 was 1540:7d028a73d7f2, checked in by athos, 14 years ago

Documented Balazs's stuff. Quite enough of that.

File size: 35.2 KB
Line 
1/* -*- C++ -*-
2 * lemon/dfs.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Research Group on Combinatorial Optimization, 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#ifdef DOXYGEN
90    static ProcessedMap *createProcessedMap(const GR &g)
91#else
92    static ProcessedMap *createProcessedMap(const GR &)
93#endif
94    {
95      return new ProcessedMap();
96    }
97    ///The type of the map that indicates which nodes are reached.
98 
99    ///The type of the map that indicates which nodes are reached.
100    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
101    ///\todo named parameter to set this type, function to read and write.
102    typedef typename Graph::template NodeMap<bool> ReachedMap;
103    ///Instantiates a ReachedMap.
104 
105    ///This function instantiates a \ref ReachedMap.
106    ///\param G is the graph, to which
107    ///we would like to define the \ref ReachedMap.
108    static ReachedMap *createReachedMap(const GR &G)
109    {
110      return new ReachedMap(G);
111    }
112    ///The type of the map that stores the dists of the nodes.
113 
114    ///The type of the map that stores the dists of the nodes.
115    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
116    ///
117    typedef typename Graph::template NodeMap<int> DistMap;
118    ///Instantiates a DistMap.
119 
120    ///This function instantiates a \ref DistMap.
121    ///\param G is the graph, to which we would like to define the \ref DistMap
122    static DistMap *createDistMap(const GR &G)
123    {
124      return new DistMap(G);
125    }
126  };
127 
128  ///%DFS algorithm class.
129 
130  ///\ingroup flowalgs
131  ///This class provides an efficient implementation of the %DFS algorithm.
132  ///
133  ///\param GR The graph type the algorithm runs on. The default value is
134  ///\ref ListGraph. The value of GR is not used directly by Dfs, it
135  ///is only passed to \ref DfsDefaultTraits.
136  ///\param TR Traits class to set various data types used by the algorithm.
137  ///The default traits class is
138  ///\ref DfsDefaultTraits "DfsDefaultTraits<GR>".
139  ///See \ref DfsDefaultTraits for the documentation of
140  ///a Dfs traits class.
141  ///
142  ///\author Jacint Szabo and Alpar Juttner
143  ///\todo A compare object would be nice.
144
145#ifdef DOXYGEN
146  template <typename GR,
147            typename TR>
148#else
149  template <typename GR=ListGraph,
150            typename TR=DfsDefaultTraits<GR> >
151#endif
152  class Dfs {
153  public:
154    /**
155     * \brief \ref Exception for uninitialized parameters.
156     *
157     * This error represents problems in the initialization
158     * of the parameters of the algorithms.
159     */
160    class UninitializedParameter : public lemon::UninitializedParameter {
161    public:
162      virtual const char* exceptionName() const {
163        return "lemon::Dfs::UninitializedParameter";
164      }
165    };
166
167    typedef TR Traits;
168    ///The type of the underlying graph.
169    typedef typename TR::Graph Graph;
170    ///\e
171    typedef typename Graph::Node Node;
172    ///\e
173    typedef typename Graph::NodeIt NodeIt;
174    ///\e
175    typedef typename Graph::Edge Edge;
176    ///\e
177    typedef typename Graph::OutEdgeIt OutEdgeIt;
178   
179    ///\brief The type of the map that stores the last
180    ///edges of the %DFS paths.
181    typedef typename TR::PredMap PredMap;
182//     ///\brief The type of the map that stores the last but one
183//     ///nodes of the %DFS paths.
184//     typedef typename TR::PredNodeMap PredNodeMap;
185    ///The type of the map indicating which nodes are reached.
186    typedef typename TR::ReachedMap ReachedMap;
187    ///The type of the map indicating which nodes are processed.
188    typedef typename TR::ProcessedMap ProcessedMap;
189    ///The type of the map that stores the dists of the nodes.
190    typedef typename TR::DistMap DistMap;
191  private:
192    /// Pointer to the underlying graph.
193    const Graph *G;
194    ///Pointer to the map of predecessors edges.
195    PredMap *_pred;
196    ///Indicates if \ref _pred is locally allocated (\c true) or not.
197    bool local_pred;
198//     ///Pointer to the map of predecessors nodes.
199//     PredNodeMap *_predNode;
200//     ///Indicates if \ref _predNode is locally allocated (\c true) or not.
201//     bool local_predNode;
202    ///Pointer to the map of distances.
203    DistMap *_dist;
204    ///Indicates if \ref _dist is locally allocated (\c true) or not.
205    bool local_dist;
206    ///Pointer to the map of reached status of the nodes.
207    ReachedMap *_reached;
208    ///Indicates if \ref _reached is locally allocated (\c true) or not.
209    bool local_reached;
210    ///Pointer to the map of processed status of the nodes.
211    ProcessedMap *_processed;
212    ///Indicates if \ref _processed is locally allocated (\c true) or not.
213    bool local_processed;
214
215    std::vector<typename Graph::OutEdgeIt> _stack;
216    int _stack_head;
217//     ///The source node of the last execution.
218//     Node source;
219
220    ///Creates the maps if necessary.
221   
222    ///\todo Error if \c G are \c NULL.
223    ///\todo Better memory allocation (instead of new).
224    void create_maps()
225    {
226      if(!_pred) {
227        local_pred = true;
228        _pred = Traits::createPredMap(*G);
229      }
230//       if(!_predNode) {
231//      local_predNode = true;
232//      _predNode = Traits::createPredNodeMap(*G);
233//       }
234      if(!_dist) {
235        local_dist = true;
236        _dist = Traits::createDistMap(*G);
237      }
238      if(!_reached) {
239        local_reached = true;
240        _reached = Traits::createReachedMap(*G);
241      }
242      if(!_processed) {
243        local_processed = true;
244        _processed = Traits::createProcessedMap(*G);
245      }
246    }
247   
248  public :
249 
250    ///\name Named template parameters
251
252    ///@{
253
254    template <class T>
255    struct DefPredMapTraits : public Traits {
256      typedef T PredMap;
257      static PredMap *createPredMap(const Graph &G)
258      {
259        throw UninitializedParameter();
260      }
261    };
262    ///\ref named-templ-param "Named parameter" for setting PredMap type
263
264    ///\ref named-templ-param "Named parameter" for setting PredMap type
265    ///
266    template <class T>
267    class DefPredMap : public Dfs< Graph,
268                                        DefPredMapTraits<T> > { };
269   
270//     template <class T>
271//     struct DefPredNodeMapTraits : public Traits {
272//       typedef T PredNodeMap;
273//       static PredNodeMap *createPredNodeMap(const Graph &G)
274//       {
275//      throw UninitializedParameter();
276//       }
277//     };
278//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
279
280//     ///\ref named-templ-param "Named parameter" for setting PredNodeMap type
281//     ///
282//     template <class T>
283//     class DefPredNodeMap : public Dfs< Graph,
284//                                          LengthMap,
285//                                          DefPredNodeMapTraits<T> > { };
286   
287    template <class T>
288    struct DefDistMapTraits : public Traits {
289      typedef T DistMap;
290      static DistMap *createDistMap(const Graph &G)
291      {
292        throw UninitializedParameter();
293      }
294    };
295    ///\ref named-templ-param "Named parameter" for setting DistMap type
296
297    ///\ref named-templ-param "Named parameter" for setting DistMap type
298    ///
299    template <class T>
300    class DefDistMap : public Dfs< Graph,
301                                   DefDistMapTraits<T> > { };
302   
303    template <class T>
304    struct DefReachedMapTraits : public Traits {
305      typedef T ReachedMap;
306      static ReachedMap *createReachedMap(const Graph &G)
307      {
308        throw UninitializedParameter();
309      }
310    };
311    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
312
313    ///\ref named-templ-param "Named parameter" for setting ReachedMap type
314    ///
315    template <class T>
316    class DefReachedMap : public Dfs< Graph,
317                                      DefReachedMapTraits<T> > { };
318   
319    struct DefGraphReachedMapTraits : public Traits {
320      typedef typename Graph::template NodeMap<bool> ReachedMap;
321      static ReachedMap *createReachedMap(const Graph &G)
322      {
323        return new ReachedMap(G);
324      }
325    };
326    template <class T>
327    struct DefProcessedMapTraits : public Traits {
328      typedef T ProcessedMap;
329      static ProcessedMap *createProcessedMap(const Graph &G)
330      {
331        throw UninitializedParameter();
332      }
333    };
334    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
335
336    ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
337    ///
338    template <class T>
339    class DefProcessedMap : public Dfs< Graph,
340                                        DefProcessedMapTraits<T> > { };
341   
342    struct DefGraphProcessedMapTraits : public Traits {
343      typedef typename Graph::template NodeMap<bool> ProcessedMap;
344      static ProcessedMap *createProcessedMap(const Graph &G)
345      {
346        return new ProcessedMap(G);
347      }
348    };
349    ///\brief \ref named-templ-param "Named parameter"
350    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
351    ///
352    ///\ref named-templ-param "Named parameter"
353    ///for setting the ProcessedMap type to be Graph::NodeMap<bool>.
354    ///If you don't set it explicitely, it will be automatically allocated.
355    template <class T>
356    class DefProcessedMapToBeDefaultMap :
357      public Dfs< Graph,
358                  DefGraphProcessedMapTraits> { };
359   
360    ///@}
361
362  public:     
363   
364    ///Constructor.
365   
366    ///\param _G the graph the algorithm will run on.
367    ///
368    Dfs(const Graph& _G) :
369      G(&_G),
370      _pred(NULL), local_pred(false),
371//       _predNode(NULL), local_predNode(false),
372      _dist(NULL), local_dist(false),
373      _reached(NULL), local_reached(false),
374      _processed(NULL), local_processed(false)
375    { }
376   
377    ///Destructor.
378    ~Dfs()
379    {
380      if(local_pred) delete _pred;
381//       if(local_predNode) delete _predNode;
382      if(local_dist) delete _dist;
383      if(local_reached) delete _reached;
384      if(local_processed) delete _processed;
385    }
386
387    ///Sets the map storing the predecessor edges.
388
389    ///Sets the map storing the predecessor edges.
390    ///If you don't use this function before calling \ref run(),
391    ///it will allocate one. The destuctor deallocates this
392    ///automatically allocated map, of course.
393    ///\return <tt> (*this) </tt>
394    Dfs &predMap(PredMap &m)
395    {
396      if(local_pred) {
397        delete _pred;
398        local_pred=false;
399      }
400      _pred = &m;
401      return *this;
402    }
403
404//     ///Sets the map storing the predecessor nodes.
405
406//     ///Sets the map storing the predecessor nodes.
407//     ///If you don't use this function before calling \ref run(),
408//     ///it will allocate one. The destuctor deallocates this
409//     ///automatically allocated map, of course.
410//     ///\return <tt> (*this) </tt>
411//     Dfs &predNodeMap(PredNodeMap &m)
412//     {
413//       if(local_predNode) {
414//      delete _predNode;
415//      local_predNode=false;
416//       }
417//       _predNode = &m;
418//       return *this;
419//     }
420
421    ///Sets the map storing the distances calculated by the algorithm.
422
423    ///Sets the map storing the distances calculated by the algorithm.
424    ///If you don't use this function before calling \ref run(),
425    ///it will allocate one. The destuctor deallocates this
426    ///automatically allocated map, of course.
427    ///\return <tt> (*this) </tt>
428    Dfs &distMap(DistMap &m)
429    {
430      if(local_dist) {
431        delete _dist;
432        local_dist=false;
433      }
434      _dist = &m;
435      return *this;
436    }
437
438    ///Sets the map indicating if a node is reached.
439
440    ///Sets the map indicating if a node is reached.
441    ///If you don't use this function before calling \ref run(),
442    ///it will allocate one. The destuctor deallocates this
443    ///automatically allocated map, of course.
444    ///\return <tt> (*this) </tt>
445    Dfs &reachedMap(ReachedMap &m)
446    {
447      if(local_reached) {
448        delete _reached;
449        local_reached=false;
450      }
451      _reached = &m;
452      return *this;
453    }
454
455    ///Sets the map indicating if a node is processed.
456
457    ///Sets the map indicating if a node is processed.
458    ///If you don't use this function before calling \ref run(),
459    ///it will allocate one. The destuctor deallocates this
460    ///automatically allocated map, of course.
461    ///\return <tt> (*this) </tt>
462    Dfs &processedMap(ProcessedMap &m)
463    {
464      if(local_processed) {
465        delete _processed;
466        local_processed=false;
467      }
468      _processed = &m;
469      return *this;
470    }
471
472  public:
473    ///\name Execution control
474    ///The simplest way to execute the algorithm is to use
475    ///one of the member functions called \c run(...).
476    ///\n
477    ///If you need more control on the execution,
478    ///first you must call \ref init(), then you can add several source nodes
479    ///with \ref addSource().
480    ///Finally \ref start() will perform the actual path
481    ///computation.
482
483    ///@{
484
485    ///Initializes the internal data structures.
486
487    ///Initializes the internal data structures.
488    ///
489    void init()
490    {
491      create_maps();
492      _stack.resize(countNodes(*G));
493      _stack_head=-1;
494      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
495        _pred->set(u,INVALID);
496        // _predNode->set(u,INVALID);
497        _reached->set(u,false);
498        _processed->set(u,false);
499      }
500    }
501   
502    ///Adds a new source node.
503
504    ///Adds a new source node to the set of nodes to be processed.
505    ///
506    ///\bug dists are wrong (or at least strange) in case of multiple sources.
507    void addSource(Node s)
508    {
509      if(!(*_reached)[s])
510        {
511          _reached->set(s,true);
512          _pred->set(s,INVALID);
513          // _predNode->set(u,INVALID);
514          _stack[++_stack_head]=OutEdgeIt(*G,s);
515          _dist->set(s,_stack_head);
516        }
517    }
518   
519    ///Processes the next edge.
520
521    ///Processes the next edge.
522    ///
523    ///\return The processed edge.
524    ///
525    ///\pre The stack must not be empty!
526    Edge processNextEdge()
527    {
528      Node m;
529      Edge e=_stack[_stack_head];
530      if(!(*_reached)[m=G->target(e)]) {
531        _pred->set(m,e);
532        _reached->set(m,true);
533        //        _pred_node->set(m,G->source(e));
534        ++_stack_head;
535        _stack[_stack_head] = OutEdgeIt(*G, m);
536        _dist->set(m,_stack_head);
537      }
538      else {
539        Node n;
540        while(_stack_head>=0 &&
541              (n=G->source(_stack[_stack_head]),
542               ++_stack[_stack_head]==INVALID))
543          {
544            _processed->set(n,true);
545            --_stack_head;
546          }
547      }
548      return e;
549    }
550     
551    ///\brief Returns \c false if there are nodes
552    ///to be processed in the queue
553    ///
554    ///Returns \c false if there are nodes
555    ///to be processed in the queue
556    bool emptyQueue() { return _stack_head<0; }
557    ///Returns the number of the nodes to be processed.
558   
559    ///Returns the number of the nodes to be processed in the queue.
560    ///
561    int queueSize() { return _stack_head+1; }
562   
563    ///Executes the algorithm.
564
565    ///Executes the algorithm.
566    ///
567    ///\pre init() must be called and at least one node should be added
568    ///with addSource() before using this function.
569    ///
570    ///This method runs the %DFS algorithm from the root node(s)
571    ///in order to
572    ///compute the
573    ///%DFS path to each node. The algorithm computes
574    ///- The %DFS tree.
575    ///- The distance of each node from the root(s) in the %DFS tree.
576    ///
577    void start()
578    {
579      while ( !emptyQueue() ) processNextEdge();
580    }
581   
582    ///Executes the algorithm until \c dest is reached.
583
584    ///Executes the algorithm until \c dest is reached.
585    ///
586    ///\pre init() must be called and at least one node should be added
587    ///with addSource() before using this function.
588    ///
589    ///This method runs the %DFS algorithm from the root node(s)
590    ///in order to
591    ///compute the
592    ///%DFS path to \c dest. The algorithm computes
593    ///- The %DFS path to \c  dest.
594    ///- The distance of \c dest from the root(s) in the %DFS tree.
595    ///
596    void start(Node dest)
597    {
598      while ( !emptyQueue() && G->target(_stack[_stack_head])!=dest )
599        processNextEdge();
600    }
601   
602    ///Executes the algorithm until a condition is met.
603
604    ///Executes the algorithm until a condition is met.
605    ///
606    ///\pre init() must be called and at least one node should be added
607    ///with addSource() before using this function.
608    ///
609    ///\param nm must be a bool (or convertible) edge map. The algorithm
610    ///will stop when it reaches an edge \c e with <tt>nm[e]==true</tt>.
611    ///
612    ///\warning Contrary to \ref Dfs and \ref Dijkstra, \c nm is an edge map,
613    ///not a node map.
614    template<class NM>
615      void start(const NM &nm)
616      {
617        while ( !emptyQueue() && !nm[_stack[_stack_head]] ) processNextEdge();
618      }
619   
620    ///Runs %DFS algorithm from node \c s.
621   
622    ///This method runs the %DFS algorithm from a root node \c s
623    ///in order to
624    ///compute the
625    ///%DFS path to each node. The algorithm computes
626    ///- The %DFS tree.
627    ///- The distance of each node from the root in the %DFS tree.
628    ///
629    ///\note d.run(s) is just a shortcut of the following code.
630    ///\code
631    ///  d.init();
632    ///  d.addSource(s);
633    ///  d.start();
634    ///\endcode
635    void run(Node s) {
636      init();
637      addSource(s);
638      start();
639    }
640   
641    ///Finds the %DFS path between \c s and \c t.
642   
643    ///Finds the %DFS path between \c s and \c t.
644    ///
645    ///\return The length of the %DFS s---t path if there exists one,
646    ///0 otherwise.
647    ///\note Apart from the return value, d.run(s,t) is
648    ///just a shortcut of the following code.
649    ///\code
650    ///  d.init();
651    ///  d.addSource(s);
652    ///  d.start(t);
653    ///\endcode
654    int run(Node s,Node t) {
655      init();
656      addSource(s);
657      start(t);
658      return reached(t)?_stack_head+1:0;
659    }
660   
661    ///@}
662
663    ///\name Query Functions
664    ///The result of the %DFS algorithm can be obtained using these
665    ///functions.\n
666    ///Before the use of these functions,
667    ///either run() or start() must be called.
668   
669    ///@{
670
671    ///Copies the path to \c t on the DFS tree into \c p
672   
673    ///This function copies the path to \c t on the DFS tree  into \c p.
674    ///If \c t is a source itself or unreachable, then it does not
675    ///alter \c p.
676    ///\todo Is this the right way to handle unreachable nodes?
677    ///
678    ///\return Returns \c true if a path to \c t was actually copied to \c p,
679    ///\c false otherwise.
680    ///\sa DirPath
681    template<class P>
682    bool getPath(P &p,Node t)
683    {
684      if(reached(t)) {
685        p.clear();
686        typename P::Builder b(p);
687        for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t))
688          b.pushFront(pred(t));
689        b.commit();
690        return true;
691      }
692      return false;
693    }
694
695    ///The distance of a node from the root(s).
696
697    ///Returns the distance of a node from the root(s).
698    ///\pre \ref run() must be called before using this function.
699    ///\warning If node \c v is unreachable from the root(s) then the return value
700    ///of this funcion is undefined.
701    int dist(Node v) const { return (*_dist)[v]; }
702
703    ///Returns the 'previous edge' of the %DFS tree.
704
705    ///For a node \c v it returns the 'previous edge'
706    ///of the %DFS path,
707    ///i.e. it returns the last edge of a %DFS path from the root(s) to \c
708    ///v. It is \ref INVALID
709    ///if \c v is unreachable from the root(s) or \c v is a root. The
710    ///%DFS tree used here is equal to the %DFS tree used in
711    ///\ref predNode(Node v).
712    ///\pre Either \ref run() or \ref start() must be called before using
713    ///this function.
714    ///\todo predEdge could be a better name.
715    Edge pred(Node v) const { return (*_pred)[v];}
716
717    ///Returns the 'previous node' of the %DFS tree.
718
719    ///For a node \c v it returns the 'previous node'
720    ///of the %DFS tree,
721    ///i.e. it returns the last but one node from a %DFS path from the
722    ///root(a) to \c /v.
723    ///It is INVALID if \c v is unreachable from the root(s) or
724    ///if \c v itself a root.
725    ///The %DFS tree used here is equal to the %DFS
726    ///tree used in \ref pred(Node v).
727    ///\pre Either \ref run() or \ref start() must be called before
728    ///using this function.
729    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
730                                  G->source((*_pred)[v]); }
731   
732    ///Returns a reference to the NodeMap of distances.
733
734    ///Returns a reference to the NodeMap of distances.
735    ///\pre Either \ref run() or \ref init() must
736    ///be called before using this function.
737    const DistMap &distMap() const { return *_dist;}
738 
739    ///Returns a reference to the %DFS edge-tree map.
740
741    ///Returns a reference to the NodeMap of the edges of the
742    ///%DFS tree.
743    ///\pre Either \ref run() or \ref init()
744    ///must be called before using this function.
745    const PredMap &predMap() const { return *_pred;}
746 
747//     ///Returns a reference to the map of nodes of %DFS paths.
748
749//     ///Returns a reference to the NodeMap of the last but one nodes of the
750//     ///%DFS tree.
751//     ///\pre \ref run() must be called before using this function.
752//     const PredNodeMap &predNodeMap() const { return *_predNode;}
753
754    ///Checks if a node is reachable from the root.
755
756    ///Returns \c true if \c v is reachable from the root(s).
757    ///\warning The source nodes are inditated as unreachable.
758    ///\pre Either \ref run() or \ref start()
759    ///must be called before using this function.
760    ///
761    bool reached(Node v) { return (*_reached)[v]; }
762   
763    ///@}
764  };
765
766  ///Default traits class of Dfs function.
767
768  ///Default traits class of Dfs function.
769  ///\param GR Graph type.
770  template<class GR>
771  struct DfsWizardDefaultTraits
772  {
773    ///The graph type the algorithm runs on.
774    typedef GR Graph;
775    ///\brief The type of the map that stores the last
776    ///edges of the %DFS paths.
777    ///
778    ///The type of the map that stores the last
779    ///edges of the %DFS paths.
780    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
781    ///
782    typedef NullMap<typename Graph::Node,typename GR::Edge> PredMap;
783    ///Instantiates a PredMap.
784 
785    ///This function instantiates a \ref PredMap.
786    ///\param g is the graph, to which we would like to define the PredMap.
787    ///\todo The graph alone may be insufficient to initialize
788#ifdef DOXYGEN
789    static PredMap *createPredMap(const GR &g)
790#else
791    static PredMap *createPredMap(const GR &)
792#endif
793    {
794      return new PredMap();
795    }
796//     ///\brief The type of the map that stores the last but one
797//     ///nodes of the %DFS paths.
798//     ///
799//     ///The type of the map that stores the last but one
800//     ///nodes of the %DFS paths.
801//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
802//     ///
803//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
804//     ///Instantiates a PredNodeMap.
805   
806//     ///This function instantiates a \ref PredNodeMap.
807//     ///\param G is the graph, to which
808//     ///we would like to define the \ref PredNodeMap
809//     static PredNodeMap *createPredNodeMap(const GR &G)
810//     {
811//       return new PredNodeMap();
812//     }
813
814    ///The type of the map that indicates which nodes are processed.
815 
816    ///The type of the map that indicates which nodes are processed.
817    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
818    ///\todo named parameter to set this type, function to read and write.
819    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
820    ///Instantiates a ProcessedMap.
821 
822    ///This function instantiates a \ref ProcessedMap.
823    ///\param g is the graph, to which
824    ///we would like to define the \ref ProcessedMap
825#ifdef DOXYGEN
826    static ProcessedMap *createProcessedMap(const GR &g)
827#else
828    static ProcessedMap *createProcessedMap(const GR &)
829#endif
830    {
831      return new ProcessedMap();
832    }
833    ///The type of the map that indicates which nodes are reached.
834 
835    ///The type of the map that indicates which nodes are reached.
836    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
837    ///\todo named parameter to set this type, function to read and write.
838    typedef typename Graph::template NodeMap<bool> ReachedMap;
839    ///Instantiates a ReachedMap.
840 
841    ///This function instantiates a \ref ReachedMap.
842    ///\param G is the graph, to which
843    ///we would like to define the \ref ReachedMap.
844    static ReachedMap *createReachedMap(const GR &G)
845    {
846      return new ReachedMap(G);
847    }
848    ///The type of the map that stores the dists of the nodes.
849 
850    ///The type of the map that stores the dists of the nodes.
851    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
852    ///
853    typedef NullMap<typename Graph::Node,int> DistMap;
854    ///Instantiates a DistMap.
855 
856    ///This function instantiates a \ref DistMap.
857    ///\param g is the graph, to which we would like to define the \ref DistMap
858#ifdef DOXYGEN
859    static DistMap *createDistMap(const GR &g)
860#else
861    static DistMap *createDistMap(const GR &)
862#endif
863    {
864      return new DistMap();
865    }
866  };
867 
868  /// Default traits used by \ref DfsWizard
869
870  /// To make it easier to use Dfs algorithm
871  ///we have created a wizard class.
872  /// This \ref DfsWizard class needs default traits,
873  ///as well as the \ref Dfs class.
874  /// The \ref DfsWizardBase is a class to be the default traits of the
875  /// \ref DfsWizard class.
876  template<class GR>
877  class DfsWizardBase : public DfsWizardDefaultTraits<GR>
878  {
879
880    typedef DfsWizardDefaultTraits<GR> Base;
881  protected:
882    /// Type of the nodes in the graph.
883    typedef typename Base::Graph::Node Node;
884
885    /// Pointer to the underlying graph.
886    void *_g;
887    ///Pointer to the map of reached nodes.
888    void *_reached;
889    ///Pointer to the map of processed nodes.
890    void *_processed;
891    ///Pointer to the map of predecessors edges.
892    void *_pred;
893//     ///Pointer to the map of predecessors nodes.
894//     void *_predNode;
895    ///Pointer to the map of distances.
896    void *_dist;
897    ///Pointer to the source node.
898    Node _source;
899   
900    public:
901    /// Constructor.
902   
903    /// This constructor does not require parameters, therefore it initiates
904    /// all of the attributes to default values (0, INVALID).
905    DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0),
906//                         _predNode(0),
907                           _dist(0), _source(INVALID) {}
908
909    /// Constructor.
910   
911    /// This constructor requires some parameters,
912    /// listed in the parameters list.
913    /// Others are initiated to 0.
914    /// \param g is the initial value of  \ref _g
915    /// \param s is the initial value of  \ref _source
916    DfsWizardBase(const GR &g, Node s=INVALID) :
917      _g((void *)&g), _reached(0), _processed(0), _pred(0),
918//       _predNode(0),
919      _dist(0), _source(s) {}
920
921  };
922 
923  /// A class to make the usage of the Dfs algorithm easier
924
925  /// This class is created to make it easier to use the Dfs algorithm.
926  /// It uses the functions and features of the plain \ref Dfs,
927  /// but it is much simpler to use it.
928  ///
929  /// Simplicity means that the way to change the types defined
930  /// in the traits class is based on functions that returns the new class
931  /// and not on templatable built-in classes.
932  /// When using the plain \ref Dfs
933  /// the new class with the modified type comes from
934  /// the original class by using the ::
935  /// operator. In the case of \ref DfsWizard only
936  /// a function have to be called and it will
937  /// return the needed class.
938  ///
939  /// It does not have own \ref run method. When its \ref run method is called
940  /// it initiates a plain \ref Dfs object, and calls the \ref Dfs::run
941  /// method of it.
942  template<class TR>
943  class DfsWizard : public TR
944  {
945    typedef TR Base;
946
947    ///The type of the underlying graph.
948    typedef typename TR::Graph Graph;
949    //\e
950    typedef typename Graph::Node Node;
951    //\e
952    typedef typename Graph::NodeIt NodeIt;
953    //\e
954    typedef typename Graph::Edge Edge;
955    //\e
956    typedef typename Graph::OutEdgeIt OutEdgeIt;
957   
958    ///\brief The type of the map that stores
959    ///the reached nodes
960    typedef typename TR::ReachedMap ReachedMap;
961    ///\brief The type of the map that stores
962    ///the processed nodes
963    typedef typename TR::ProcessedMap ProcessedMap;
964    ///\brief The type of the map that stores the last
965    ///edges of the %DFS paths.
966    typedef typename TR::PredMap PredMap;
967//     ///\brief The type of the map that stores the last but one
968//     ///nodes of the %DFS paths.
969//     typedef typename TR::PredNodeMap PredNodeMap;
970    ///The type of the map that stores the distances of the nodes.
971    typedef typename TR::DistMap DistMap;
972
973public:
974    /// Constructor.
975    DfsWizard() : TR() {}
976
977    /// Constructor that requires parameters.
978
979    /// Constructor that requires parameters.
980    /// These parameters will be the default values for the traits class.
981    DfsWizard(const Graph &g, Node s=INVALID) :
982      TR(g,s) {}
983
984    ///Copy constructor
985    DfsWizard(const TR &b) : TR(b) {}
986
987    ~DfsWizard() {}
988
989    ///Runs Dfs algorithm from a given node.
990   
991    ///Runs Dfs algorithm from a given node.
992    ///The node can be given by the \ref source function.
993    void run()
994    {
995      if(Base::_source==INVALID) throw UninitializedParameter();
996      Dfs<Graph,TR> alg(*(Graph*)Base::_g);
997      if(Base::_reached) alg.reachedMap(*(ReachedMap*)Base::_reached);
998      if(Base::_processed) alg.processedMap(*(ProcessedMap*)Base::_processed);
999      if(Base::_pred) alg.predMap(*(PredMap*)Base::_pred);
1000//       if(Base::_predNode) alg.predNodeMap(*(PredNodeMap*)Base::_predNode);
1001      if(Base::_dist) alg.distMap(*(DistMap*)Base::_dist);
1002      alg.run(Base::_source);
1003    }
1004
1005    ///Runs Dfs algorithm from the given node.
1006
1007    ///Runs Dfs algorithm from the given node.
1008    ///\param s is the given source.
1009    void run(Node s)
1010    {
1011      Base::_source=s;
1012      run();
1013    }
1014
1015    template<class T>
1016    struct DefPredMapBase : public Base {
1017      typedef T PredMap;
1018      static PredMap *createPredMap(const Graph &) { return 0; };
1019      DefPredMapBase(const TR &b) : TR(b) {}
1020    };
1021   
1022    ///\brief \ref named-templ-param "Named parameter"
1023    ///function for setting PredMap type
1024    ///
1025    /// \ref named-templ-param "Named parameter"
1026    ///function for setting PredMap type
1027    ///
1028    template<class T>
1029    DfsWizard<DefPredMapBase<T> > predMap(const T &t)
1030    {
1031      Base::_pred=(void *)&t;
1032      return DfsWizard<DefPredMapBase<T> >(*this);
1033    }
1034   
1035 
1036    template<class T>
1037    struct DefReachedMapBase : public Base {
1038      typedef T ReachedMap;
1039      static ReachedMap *createReachedMap(const Graph &) { return 0; };
1040      DefReachedMapBase(const TR &b) : TR(b) {}
1041    };
1042   
1043    ///\brief \ref named-templ-param "Named parameter"
1044    ///function for setting ReachedMap
1045    ///
1046    /// \ref named-templ-param "Named parameter"
1047    ///function for setting ReachedMap
1048    ///
1049    template<class T>
1050    DfsWizard<DefReachedMapBase<T> > reachedMap(const T &t)
1051    {
1052      Base::_pred=(void *)&t;
1053      return DfsWizard<DefReachedMapBase<T> >(*this);
1054    }
1055   
1056
1057    template<class T>
1058    struct DefProcessedMapBase : public Base {
1059      typedef T ProcessedMap;
1060      static ProcessedMap *createProcessedMap(const Graph &) { return 0; };
1061      DefProcessedMapBase(const TR &b) : TR(b) {}
1062    };
1063   
1064    ///\brief \ref named-templ-param "Named parameter"
1065    ///function for setting ProcessedMap
1066    ///
1067    /// \ref named-templ-param "Named parameter"
1068    ///function for setting ProcessedMap
1069    ///
1070    template<class T>
1071    DfsWizard<DefProcessedMapBase<T> > processedMap(const T &t)
1072    {
1073      Base::_pred=(void *)&t;
1074      return DfsWizard<DefProcessedMapBase<T> >(*this);
1075    }
1076   
1077
1078//     template<class T>
1079//     struct DefPredNodeMapBase : public Base {
1080//       typedef T PredNodeMap;
1081//       static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
1082//       DefPredNodeMapBase(const TR &b) : TR(b) {}
1083//     };
1084   
1085//     ///\brief \ref named-templ-param "Named parameter"
1086//     ///function for setting PredNodeMap type
1087//     ///
1088//     /// \ref named-templ-param "Named parameter"
1089//     ///function for setting PredNodeMap type
1090//     ///
1091//     template<class T>
1092//     DfsWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
1093//     {
1094//       Base::_predNode=(void *)&t;
1095//       return DfsWizard<DefPredNodeMapBase<T> >(*this);
1096//     }
1097   
1098    template<class T>
1099    struct DefDistMapBase : public Base {
1100      typedef T DistMap;
1101      static DistMap *createDistMap(const Graph &) { return 0; };
1102      DefDistMapBase(const TR &b) : TR(b) {}
1103    };
1104   
1105    ///\brief \ref named-templ-param "Named parameter"
1106    ///function for setting DistMap type
1107    ///
1108    /// \ref named-templ-param "Named parameter"
1109    ///function for setting DistMap type
1110    ///
1111    template<class T>
1112    DfsWizard<DefDistMapBase<T> > distMap(const T &t)
1113    {
1114      Base::_dist=(void *)&t;
1115      return DfsWizard<DefDistMapBase<T> >(*this);
1116    }
1117   
1118    /// Sets the source node, from which the Dfs algorithm runs.
1119
1120    /// Sets the source node, from which the Dfs algorithm runs.
1121    /// \param s is the source node.
1122    DfsWizard<TR> &source(Node s)
1123    {
1124      Base::_source=s;
1125      return *this;
1126    }
1127   
1128  };
1129 
1130  ///Function type interface for Dfs algorithm.
1131
1132  /// \ingroup flowalgs
1133  ///Function type interface for Dfs algorithm.
1134  ///
1135  ///This function also has several
1136  ///\ref named-templ-func-param "named parameters",
1137  ///they are declared as the members of class \ref DfsWizard.
1138  ///The following
1139  ///example shows how to use these parameters.
1140  ///\code
1141  ///  dfs(g,source).predMap(preds).run();
1142  ///\endcode
1143  ///\warning Don't forget to put the \ref DfsWizard::run() "run()"
1144  ///to the end of the parameter list.
1145  ///\sa DfsWizard
1146  ///\sa Dfs
1147  template<class GR>
1148  DfsWizard<DfsWizardBase<GR> >
1149  dfs(const GR &g,typename GR::Node s=INVALID)
1150  {
1151    return DfsWizard<DfsWizardBase<GR> >(g,s);
1152  }
1153
1154} //END OF NAMESPACE LEMON
1155
1156#endif
1157
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