COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/dfs.h @ 1443:70781827eb2f

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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    static ProcessedMap *createProcessedMap(const GR &)
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 dists 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    ///\pre 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) in the %DFS tree.
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) in the %DFS tree.
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 an edge \c e with <tt>nm[e]==true</tt>.
604    ///
605    ///\warning Contrary to \ref Dfs and \ref Dijkstra, \c nm is an edge map,
606    ///not a node map.
607    template<class NM>
608      void start(const NM &nm)
609      {
610        while ( !emptyQueue() && !nm[_stack[_stack_head]] ) processNextEdge();
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) 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    ///Copies the path to \c t on the DFS tree into \c p
665   
666    ///This function copies the path to \c t on the DFS tree  into \c p.
667    ///If \c t is a source itself or unreachable, then it does not
668    ///alter \c p.
669    ///\todo Is this the right way to handle unreachable nodes?
670    ///
671    ///\return Returns \c true if a path to \c t was actually copied to \c p,
672    ///\c false otherwise.
673    ///\sa DirPath
674    template<class P>
675    bool getPath(P &p,Node t)
676    {
677      if(reached(t)) {
678        p.clear();
679        typename P::Builder b(p);
680        for(b.setStartNode(t);pred(t)!=INVALID;t=predNode(t))
681          b.pushFront(pred(t));
682        b.commit();
683        return true;
684      }
685      return false;
686    }
687
688    ///The distance of a node from the root(s).
689
690    ///Returns the distance of a node from the root(s).
691    ///\pre \ref run() must be called before using this function.
692    ///\warning If node \c v is unreachable from the root(s) then the return value
693    ///of this funcion is undefined.
694    int dist(Node v) const { return (*_dist)[v]; }
695
696    ///Returns the 'previous edge' of the %DFS tree.
697
698    ///For a node \c v it returns the 'previous edge'
699    ///of the %DFS path,
700    ///i.e. it returns the last edge of a %DFS path from the root(s) to \c
701    ///v. It is \ref INVALID
702    ///if \c v is unreachable from the root(s) or \c v is a root. The
703    ///%DFS tree used here is equal to the %DFS tree used in
704    ///\ref predNode(Node v).
705    ///\pre Either \ref run() or \ref start() must be called before using
706    ///this function.
707    ///\todo predEdge could be a better name.
708    Edge pred(Node v) const { return (*_pred)[v];}
709
710    ///Returns the 'previous node' of the %DFS tree.
711
712    ///For a node \c v it returns the 'previous node'
713    ///of the %DFS tree,
714    ///i.e. it returns the last but one node from a %DFS path from the
715    ///root(a) to \c /v.
716    ///It is INVALID if \c v is unreachable from the root(s) or
717    ///if \c v itself a root.
718    ///The %DFS tree used here is equal to the %DFS
719    ///tree used in \ref pred(Node v).
720    ///\pre Either \ref run() or \ref start() must be called before
721    ///using this function.
722    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
723                                  G->source((*_pred)[v]); }
724   
725    ///Returns a reference to the NodeMap of distances.
726
727    ///Returns a reference to the NodeMap of distances.
728    ///\pre Either \ref run() or \ref init() must
729    ///be called before using this function.
730    const DistMap &distMap() const { return *_dist;}
731 
732    ///Returns a reference to the %DFS edge-tree map.
733
734    ///Returns a reference to the NodeMap of the edges of the
735    ///%DFS tree.
736    ///\pre Either \ref run() or \ref init()
737    ///must be called before using this function.
738    const PredMap &predMap() const { return *_pred;}
739 
740//     ///Returns a reference to the map of nodes of %DFS paths.
741
742//     ///Returns a reference to the NodeMap of the last but one nodes of the
743//     ///%DFS tree.
744//     ///\pre \ref run() must be called before using this function.
745//     const PredNodeMap &predNodeMap() const { return *_predNode;}
746
747    ///Checks if a node is reachable from the root.
748
749    ///Returns \c true if \c v is reachable from the root(s).
750    ///\warning The source nodes are inditated as unreachable.
751    ///\pre Either \ref run() or \ref start()
752    ///must be called before using this function.
753    ///
754    bool reached(Node v) { return (*_reached)[v]; }
755   
756    ///@}
757  };
758
759  ///Default traits class of Dfs function.
760
761  ///Default traits class of Dfs function.
762  ///\param GR Graph type.
763  template<class GR>
764  struct DfsWizardDefaultTraits
765  {
766    ///The graph type the algorithm runs on.
767    typedef GR Graph;
768    ///\brief The type of the map that stores the last
769    ///edges of the %DFS paths.
770    ///
771    ///The type of the map that stores the last
772    ///edges of the %DFS paths.
773    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
774    ///
775    typedef NullMap<typename Graph::Node,typename GR::Edge> PredMap;
776    ///Instantiates a PredMap.
777 
778    ///This function instantiates a \ref PredMap.
779    ///\param G is the graph, to which we would like to define the PredMap.
780    ///\todo The graph alone may be insufficient to initialize
781    static PredMap *createPredMap(const GR &)
782    {
783      return new PredMap();
784    }
785//     ///\brief The type of the map that stores the last but one
786//     ///nodes of the %DFS paths.
787//     ///
788//     ///The type of the map that stores the last but one
789//     ///nodes of the %DFS paths.
790//     ///It must meet the \ref concept::WriteMap "WriteMap" concept.
791//     ///
792//     typedef NullMap<typename Graph::Node,typename Graph::Node> PredNodeMap;
793//     ///Instantiates a PredNodeMap.
794   
795//     ///This function instantiates a \ref PredNodeMap.
796//     ///\param G is the graph, to which
797//     ///we would like to define the \ref PredNodeMap
798//     static PredNodeMap *createPredNodeMap(const GR &G)
799//     {
800//       return new PredNodeMap();
801//     }
802
803    ///The type of the map that indicates which nodes are processed.
804 
805    ///The type of the map that indicates which nodes are processed.
806    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
807    ///\todo named parameter to set this type, function to read and write.
808    typedef NullMap<typename Graph::Node,bool> ProcessedMap;
809    ///Instantiates a ProcessedMap.
810 
811    ///This function instantiates a \ref ProcessedMap.
812    ///\param G is the graph, to which
813    ///we would like to define the \ref ProcessedMap
814    static ProcessedMap *createProcessedMap(const GR &)
815    {
816      return new ProcessedMap();
817    }
818    ///The type of the map that indicates which nodes are reached.
819 
820    ///The type of the map that indicates which nodes are reached.
821    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
822    ///\todo named parameter to set this type, function to read and write.
823    typedef typename Graph::template NodeMap<bool> ReachedMap;
824    ///Instantiates a ReachedMap.
825 
826    ///This function instantiates a \ref ReachedMap.
827    ///\param G is the graph, to which
828    ///we would like to define the \ref ReachedMap.
829    static ReachedMap *createReachedMap(const GR &G)
830    {
831      return new ReachedMap(G);
832    }
833    ///The type of the map that stores the dists of the nodes.
834 
835    ///The type of the map that stores the dists of the nodes.
836    ///It must meet the \ref concept::WriteMap "WriteMap" concept.
837    ///
838    typedef NullMap<typename Graph::Node,int> DistMap;
839    ///Instantiates a DistMap.
840 
841    ///This function instantiates a \ref DistMap.
842    ///\param G is the graph, to which we would like to define the \ref DistMap
843    static DistMap *createDistMap(const GR &)
844    {
845      return new DistMap();
846    }
847  };
848 
849  /// Default traits used by \ref DfsWizard
850
851  /// To make it easier to use Dfs algorithm
852  ///we have created a wizard class.
853  /// This \ref DfsWizard class needs default traits,
854  ///as well as the \ref Dfs class.
855  /// The \ref DfsWizardBase is a class to be the default traits of the
856  /// \ref DfsWizard class.
857  template<class GR>
858  class DfsWizardBase : public DfsWizardDefaultTraits<GR>
859  {
860
861    typedef DfsWizardDefaultTraits<GR> Base;
862  protected:
863    /// Type of the nodes in the graph.
864    typedef typename Base::Graph::Node Node;
865
866    /// Pointer to the underlying graph.
867    void *_g;
868    ///Pointer to the map of reached nodes.
869    void *_reached;
870    ///Pointer to the map of processed nodes.
871    void *_processed;
872    ///Pointer to the map of predecessors edges.
873    void *_pred;
874//     ///Pointer to the map of predecessors nodes.
875//     void *_predNode;
876    ///Pointer to the map of distances.
877    void *_dist;
878    ///Pointer to the source node.
879    Node _source;
880   
881    public:
882    /// Constructor.
883   
884    /// This constructor does not require parameters, therefore it initiates
885    /// all of the attributes to default values (0, INVALID).
886    DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0),
887//                         _predNode(0),
888                           _dist(0), _source(INVALID) {}
889
890    /// Constructor.
891   
892    /// This constructor requires some parameters,
893    /// listed in the parameters list.
894    /// Others are initiated to 0.
895    /// \param g is the initial value of  \ref _g
896    /// \param s is the initial value of  \ref _source
897    DfsWizardBase(const GR &g, Node s=INVALID) :
898      _g((void *)&g), _reached(0), _processed(0), _pred(0),
899//       _predNode(0),
900      _dist(0), _source(s) {}
901
902  };
903 
904  /// A class to make the usage of the Dfs algorithm easier
905
906  /// This class is created to make it easier to use the Dfs algorithm.
907  /// It uses the functions and features of the plain \ref Dfs,
908  /// but it is much simpler to use it.
909  ///
910  /// Simplicity means that the way to change the types defined
911  /// in the traits class is based on functions that returns the new class
912  /// and not on templatable built-in classes.
913  /// When using the plain \ref Dfs
914  /// the new class with the modified type comes from
915  /// the original class by using the ::
916  /// operator. In the case of \ref DfsWizard only
917  /// a function have to be called and it will
918  /// return the needed class.
919  ///
920  /// It does not have own \ref run method. When its \ref run method is called
921  /// it initiates a plain \ref Dfs object, and calls the \ref Dfs::run
922  /// method of it.
923  template<class TR>
924  class DfsWizard : public TR
925  {
926    typedef TR Base;
927
928    ///The type of the underlying graph.
929    typedef typename TR::Graph Graph;
930    //\e
931    typedef typename Graph::Node Node;
932    //\e
933    typedef typename Graph::NodeIt NodeIt;
934    //\e
935    typedef typename Graph::Edge Edge;
936    //\e
937    typedef typename Graph::OutEdgeIt OutEdgeIt;
938   
939    ///\brief The type of the map that stores
940    ///the reached nodes
941    typedef typename TR::ReachedMap ReachedMap;
942    ///\brief The type of the map that stores
943    ///the processed nodes
944    typedef typename TR::ProcessedMap ProcessedMap;
945    ///\brief The type of the map that stores the last
946    ///edges of the %DFS paths.
947    typedef typename TR::PredMap PredMap;
948//     ///\brief The type of the map that stores the last but one
949//     ///nodes of the %DFS paths.
950//     typedef typename TR::PredNodeMap PredNodeMap;
951    ///The type of the map that stores the distances of the nodes.
952    typedef typename TR::DistMap DistMap;
953
954public:
955    /// Constructor.
956    DfsWizard() : TR() {}
957
958    /// Constructor that requires parameters.
959
960    /// Constructor that requires parameters.
961    /// These parameters will be the default values for the traits class.
962    DfsWizard(const Graph &g, Node s=INVALID) :
963      TR(g,s) {}
964
965    ///Copy constructor
966    DfsWizard(const TR &b) : TR(b) {}
967
968    ~DfsWizard() {}
969
970    ///Runs Dfs algorithm from a given node.
971   
972    ///Runs Dfs algorithm from a given node.
973    ///The node can be given by the \ref source function.
974    void run()
975    {
976      if(Base::_source==INVALID) throw UninitializedParameter();
977      Dfs<Graph,TR> alg(*(Graph*)Base::_g);
978      if(Base::_reached) alg.reachedMap(*(ReachedMap*)Base::_reached);
979      if(Base::_processed) alg.processedMap(*(ProcessedMap*)Base::_processed);
980      if(Base::_pred) alg.predMap(*(PredMap*)Base::_pred);
981//       if(Base::_predNode) alg.predNodeMap(*(PredNodeMap*)Base::_predNode);
982      if(Base::_dist) alg.distMap(*(DistMap*)Base::_dist);
983      alg.run(Base::_source);
984    }
985
986    ///Runs Dfs algorithm from the given node.
987
988    ///Runs Dfs algorithm from the given node.
989    ///\param s is the given source.
990    void run(Node s)
991    {
992      Base::_source=s;
993      run();
994    }
995
996    template<class T>
997    struct DefPredMapBase : public Base {
998      typedef T PredMap;
999      static PredMap *createPredMap(const Graph &) { return 0; };
1000      DefPredMapBase(const TR &b) : TR(b) {}
1001    };
1002   
1003    ///\brief \ref named-templ-param "Named parameter"
1004    ///function for setting PredMap type
1005    ///
1006    /// \ref named-templ-param "Named parameter"
1007    ///function for setting PredMap type
1008    ///
1009    template<class T>
1010    DfsWizard<DefPredMapBase<T> > predMap(const T &t)
1011    {
1012      Base::_pred=(void *)&t;
1013      return DfsWizard<DefPredMapBase<T> >(*this);
1014    }
1015   
1016 
1017    template<class T>
1018    struct DefReachedMapBase : public Base {
1019      typedef T ReachedMap;
1020      static ReachedMap *createReachedMap(const Graph &) { return 0; };
1021      DefReachedMapBase(const TR &b) : TR(b) {}
1022    };
1023   
1024    ///\brief \ref named-templ-param "Named parameter"
1025    ///function for setting ReachedMap
1026    ///
1027    /// \ref named-templ-param "Named parameter"
1028    ///function for setting ReachedMap
1029    ///
1030    template<class T>
1031    DfsWizard<DefReachedMapBase<T> > reachedMap(const T &t)
1032    {
1033      Base::_pred=(void *)&t;
1034      return DfsWizard<DefReachedMapBase<T> >(*this);
1035    }
1036   
1037
1038    template<class T>
1039    struct DefProcessedMapBase : public Base {
1040      typedef T ProcessedMap;
1041      static ProcessedMap *createProcessedMap(const Graph &) { return 0; };
1042      DefProcessedMapBase(const TR &b) : TR(b) {}
1043    };
1044   
1045    ///\brief \ref named-templ-param "Named parameter"
1046    ///function for setting ProcessedMap
1047    ///
1048    /// \ref named-templ-param "Named parameter"
1049    ///function for setting ProcessedMap
1050    ///
1051    template<class T>
1052    DfsWizard<DefProcessedMapBase<T> > processedMap(const T &t)
1053    {
1054      Base::_pred=(void *)&t;
1055      return DfsWizard<DefProcessedMapBase<T> >(*this);
1056    }
1057   
1058
1059//     template<class T>
1060//     struct DefPredNodeMapBase : public Base {
1061//       typedef T PredNodeMap;
1062//       static PredNodeMap *createPredNodeMap(const Graph &G) { return 0; };
1063//       DefPredNodeMapBase(const TR &b) : TR(b) {}
1064//     };
1065   
1066//     ///\brief \ref named-templ-param "Named parameter"
1067//     ///function for setting PredNodeMap type
1068//     ///
1069//     /// \ref named-templ-param "Named parameter"
1070//     ///function for setting PredNodeMap type
1071//     ///
1072//     template<class T>
1073//     DfsWizard<DefPredNodeMapBase<T> > predNodeMap(const T &t)
1074//     {
1075//       Base::_predNode=(void *)&t;
1076//       return DfsWizard<DefPredNodeMapBase<T> >(*this);
1077//     }
1078   
1079    template<class T>
1080    struct DefDistMapBase : public Base {
1081      typedef T DistMap;
1082      static DistMap *createDistMap(const Graph &) { return 0; };
1083      DefDistMapBase(const TR &b) : TR(b) {}
1084    };
1085   
1086    ///\brief \ref named-templ-param "Named parameter"
1087    ///function for setting DistMap type
1088    ///
1089    /// \ref named-templ-param "Named parameter"
1090    ///function for setting DistMap type
1091    ///
1092    template<class T>
1093    DfsWizard<DefDistMapBase<T> > distMap(const T &t)
1094    {
1095      Base::_dist=(void *)&t;
1096      return DfsWizard<DefDistMapBase<T> >(*this);
1097    }
1098   
1099    /// Sets the source node, from which the Dfs algorithm runs.
1100
1101    /// Sets the source node, from which the Dfs algorithm runs.
1102    /// \param s is the source node.
1103    DfsWizard<TR> &source(Node s)
1104    {
1105      Base::_source=s;
1106      return *this;
1107    }
1108   
1109  };
1110 
1111  ///Function type interface for Dfs algorithm.
1112
1113  /// \ingroup flowalgs
1114  ///Function type interface for Dfs algorithm.
1115  ///
1116  ///This function also has several
1117  ///\ref named-templ-func-param "named parameters",
1118  ///they are declared as the members of class \ref DfsWizard.
1119  ///The following
1120  ///example shows how to use these parameters.
1121  ///\code
1122  ///  dfs(g,source).predMap(preds).run();
1123  ///\endcode
1124  ///\warning Don't forget to put the \ref DfsWizard::run() "run()"
1125  ///to the end of the parameter list.
1126  ///\sa DfsWizard
1127  ///\sa Dfs
1128  template<class GR>
1129  DfsWizard<DfsWizardBase<GR> >
1130  dfs(const GR &g,typename GR::Node s=INVALID)
1131  {
1132    return DfsWizard<DfsWizardBase<GR> >(g,s);
1133  }
1134
1135} //END OF NAMESPACE LEMON
1136
1137#endif
1138
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