... |
... |
@@ -368,385 +368,385 @@
|
368 |
368 |
_reached = &m;
|
369 |
369 |
return *this;
|
370 |
370 |
}
|
371 |
371 |
|
372 |
372 |
///Sets the map that indicates which nodes are processed.
|
373 |
373 |
|
374 |
374 |
///Sets the map that indicates which nodes are processed.
|
375 |
375 |
///If you don't use this function before calling \ref run(Node) "run()"
|
376 |
376 |
///or \ref init(), an instance will be allocated automatically.
|
377 |
377 |
///The destructor deallocates this automatically allocated map,
|
378 |
378 |
///of course.
|
379 |
379 |
///\return <tt> (*this) </tt>
|
380 |
380 |
Dfs &processedMap(ProcessedMap &m)
|
381 |
381 |
{
|
382 |
382 |
if(local_processed) {
|
383 |
383 |
delete _processed;
|
384 |
384 |
local_processed=false;
|
385 |
385 |
}
|
386 |
386 |
_processed = &m;
|
387 |
387 |
return *this;
|
388 |
388 |
}
|
389 |
389 |
|
390 |
390 |
///Sets the map that stores the distances of the nodes.
|
391 |
391 |
|
392 |
392 |
///Sets the map that stores the distances of the nodes calculated by
|
393 |
393 |
///the algorithm.
|
394 |
394 |
///If you don't use this function before calling \ref run(Node) "run()"
|
395 |
395 |
///or \ref init(), an instance will be allocated automatically.
|
396 |
396 |
///The destructor deallocates this automatically allocated map,
|
397 |
397 |
///of course.
|
398 |
398 |
///\return <tt> (*this) </tt>
|
399 |
399 |
Dfs &distMap(DistMap &m)
|
400 |
400 |
{
|
401 |
401 |
if(local_dist) {
|
402 |
402 |
delete _dist;
|
403 |
403 |
local_dist=false;
|
404 |
404 |
}
|
405 |
405 |
_dist = &m;
|
406 |
406 |
return *this;
|
407 |
407 |
}
|
408 |
408 |
|
409 |
409 |
public:
|
410 |
410 |
|
411 |
411 |
///\name Execution Control
|
412 |
412 |
///The simplest way to execute the DFS algorithm is to use one of the
|
413 |
413 |
///member functions called \ref run(Node) "run()".\n
|
414 |
414 |
///If you need more control on the execution, first you have to call
|
415 |
415 |
///\ref init(), then you can add a source node with \ref addSource()
|
416 |
416 |
///and perform the actual computation with \ref start().
|
417 |
417 |
///This procedure can be repeated if there are nodes that have not
|
418 |
418 |
///been reached.
|
419 |
419 |
|
420 |
420 |
///@{
|
421 |
421 |
|
422 |
422 |
///\brief Initializes the internal data structures.
|
423 |
423 |
///
|
424 |
424 |
///Initializes the internal data structures.
|
425 |
425 |
void init()
|
426 |
426 |
{
|
427 |
427 |
create_maps();
|
428 |
428 |
_stack.resize(countNodes(*G));
|
429 |
429 |
_stack_head=-1;
|
430 |
430 |
for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
|
431 |
431 |
_pred->set(u,INVALID);
|
432 |
432 |
_reached->set(u,false);
|
433 |
433 |
_processed->set(u,false);
|
434 |
434 |
}
|
435 |
435 |
}
|
436 |
436 |
|
437 |
437 |
///Adds a new source node.
|
438 |
438 |
|
439 |
439 |
///Adds a new source node to the set of nodes to be processed.
|
440 |
440 |
///
|
441 |
441 |
///\pre The stack must be empty. Otherwise the algorithm gives
|
442 |
442 |
///wrong results. (One of the outgoing arcs of all the source nodes
|
443 |
443 |
///except for the last one will not be visited and distances will
|
444 |
444 |
///also be wrong.)
|
445 |
445 |
void addSource(Node s)
|
446 |
446 |
{
|
447 |
447 |
LEMON_DEBUG(emptyQueue(), "The stack is not empty.");
|
448 |
448 |
if(!(*_reached)[s])
|
449 |
449 |
{
|
450 |
450 |
_reached->set(s,true);
|
451 |
451 |
_pred->set(s,INVALID);
|
452 |
452 |
OutArcIt e(*G,s);
|
453 |
453 |
if(e!=INVALID) {
|
454 |
454 |
_stack[++_stack_head]=e;
|
455 |
455 |
_dist->set(s,_stack_head);
|
456 |
456 |
}
|
457 |
457 |
else {
|
458 |
458 |
_processed->set(s,true);
|
459 |
459 |
_dist->set(s,0);
|
460 |
460 |
}
|
461 |
461 |
}
|
462 |
462 |
}
|
463 |
463 |
|
464 |
464 |
///Processes the next arc.
|
465 |
465 |
|
466 |
466 |
///Processes the next arc.
|
467 |
467 |
///
|
468 |
468 |
///\return The processed arc.
|
469 |
469 |
///
|
470 |
470 |
///\pre The stack must not be empty.
|
471 |
471 |
Arc processNextArc()
|
472 |
472 |
{
|
473 |
473 |
Node m;
|
474 |
474 |
Arc e=_stack[_stack_head];
|
475 |
475 |
if(!(*_reached)[m=G->target(e)]) {
|
476 |
476 |
_pred->set(m,e);
|
477 |
477 |
_reached->set(m,true);
|
478 |
478 |
++_stack_head;
|
479 |
479 |
_stack[_stack_head] = OutArcIt(*G, m);
|
480 |
480 |
_dist->set(m,_stack_head);
|
481 |
481 |
}
|
482 |
482 |
else {
|
483 |
483 |
m=G->source(e);
|
484 |
484 |
++_stack[_stack_head];
|
485 |
485 |
}
|
486 |
486 |
while(_stack_head>=0 && _stack[_stack_head]==INVALID) {
|
487 |
487 |
_processed->set(m,true);
|
488 |
488 |
--_stack_head;
|
489 |
489 |
if(_stack_head>=0) {
|
490 |
490 |
m=G->source(_stack[_stack_head]);
|
491 |
491 |
++_stack[_stack_head];
|
492 |
492 |
}
|
493 |
493 |
}
|
494 |
494 |
return e;
|
495 |
495 |
}
|
496 |
496 |
|
497 |
497 |
///Next arc to be processed.
|
498 |
498 |
|
499 |
499 |
///Next arc to be processed.
|
500 |
500 |
///
|
501 |
501 |
///\return The next arc to be processed or \c INVALID if the stack
|
502 |
502 |
///is empty.
|
503 |
503 |
OutArcIt nextArc() const
|
504 |
504 |
{
|
505 |
505 |
return _stack_head>=0?_stack[_stack_head]:INVALID;
|
506 |
506 |
}
|
507 |
507 |
|
508 |
508 |
///Returns \c false if there are nodes to be processed.
|
509 |
509 |
|
510 |
510 |
///Returns \c false if there are nodes to be processed
|
511 |
511 |
///in the queue (stack).
|
512 |
512 |
bool emptyQueue() const { return _stack_head<0; }
|
513 |
513 |
|
514 |
514 |
///Returns the number of the nodes to be processed.
|
515 |
515 |
|
516 |
516 |
///Returns the number of the nodes to be processed
|
517 |
517 |
///in the queue (stack).
|
518 |
518 |
int queueSize() const { return _stack_head+1; }
|
519 |
519 |
|
520 |
520 |
///Executes the algorithm.
|
521 |
521 |
|
522 |
522 |
///Executes the algorithm.
|
523 |
523 |
///
|
524 |
524 |
///This method runs the %DFS algorithm from the root node
|
525 |
525 |
///in order to compute the DFS path to each node.
|
526 |
526 |
///
|
527 |
527 |
/// The algorithm computes
|
528 |
528 |
///- the %DFS tree,
|
529 |
529 |
///- the distance of each node from the root in the %DFS tree.
|
530 |
530 |
///
|
531 |
531 |
///\pre init() must be called and a root node should be
|
532 |
532 |
///added with addSource() before using this function.
|
533 |
533 |
///
|
534 |
534 |
///\note <tt>d.start()</tt> is just a shortcut of the following code.
|
535 |
535 |
///\code
|
536 |
536 |
/// while ( !d.emptyQueue() ) {
|
537 |
537 |
/// d.processNextArc();
|
538 |
538 |
/// }
|
539 |
539 |
///\endcode
|
540 |
540 |
void start()
|
541 |
541 |
{
|
542 |
542 |
while ( !emptyQueue() ) processNextArc();
|
543 |
543 |
}
|
544 |
544 |
|
545 |
545 |
///Executes the algorithm until the given target node is reached.
|
546 |
546 |
|
547 |
547 |
///Executes the algorithm until the given target node is reached.
|
548 |
548 |
///
|
549 |
549 |
///This method runs the %DFS algorithm from the root node
|
550 |
550 |
///in order to compute the DFS path to \c t.
|
551 |
551 |
///
|
552 |
552 |
///The algorithm computes
|
553 |
553 |
///- the %DFS path to \c t,
|
554 |
554 |
///- the distance of \c t from the root in the %DFS tree.
|
555 |
555 |
///
|
556 |
556 |
///\pre init() must be called and a root node should be
|
557 |
557 |
///added with addSource() before using this function.
|
558 |
558 |
void start(Node t)
|
559 |
559 |
{
|
560 |
|
while ( !emptyQueue() && G->target(_stack[_stack_head])!=t )
|
|
560 |
while ( !emptyQueue() && !(*_reached)[t] )
|
561 |
561 |
processNextArc();
|
562 |
562 |
}
|
563 |
563 |
|
564 |
564 |
///Executes the algorithm until a condition is met.
|
565 |
565 |
|
566 |
566 |
///Executes the algorithm until a condition is met.
|
567 |
567 |
///
|
568 |
568 |
///This method runs the %DFS algorithm from the root node
|
569 |
569 |
///until an arc \c a with <tt>am[a]</tt> true is found.
|
570 |
570 |
///
|
571 |
571 |
///\param am A \c bool (or convertible) arc map. The algorithm
|
572 |
572 |
///will stop when it reaches an arc \c a with <tt>am[a]</tt> true.
|
573 |
573 |
///
|
574 |
574 |
///\return The reached arc \c a with <tt>am[a]</tt> true or
|
575 |
575 |
///\c INVALID if no such arc was found.
|
576 |
576 |
///
|
577 |
577 |
///\pre init() must be called and a root node should be
|
578 |
578 |
///added with addSource() before using this function.
|
579 |
579 |
///
|
580 |
580 |
///\warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map,
|
581 |
581 |
///not a node map.
|
582 |
582 |
template<class ArcBoolMap>
|
583 |
583 |
Arc start(const ArcBoolMap &am)
|
584 |
584 |
{
|
585 |
585 |
while ( !emptyQueue() && !am[_stack[_stack_head]] )
|
586 |
586 |
processNextArc();
|
587 |
587 |
return emptyQueue() ? INVALID : _stack[_stack_head];
|
588 |
588 |
}
|
589 |
589 |
|
590 |
590 |
///Runs the algorithm from the given source node.
|
591 |
591 |
|
592 |
592 |
///This method runs the %DFS algorithm from node \c s
|
593 |
593 |
///in order to compute the DFS path to each node.
|
594 |
594 |
///
|
595 |
595 |
///The algorithm computes
|
596 |
596 |
///- the %DFS tree,
|
597 |
597 |
///- the distance of each node from the root in the %DFS tree.
|
598 |
598 |
///
|
599 |
599 |
///\note <tt>d.run(s)</tt> is just a shortcut of the following code.
|
600 |
600 |
///\code
|
601 |
601 |
/// d.init();
|
602 |
602 |
/// d.addSource(s);
|
603 |
603 |
/// d.start();
|
604 |
604 |
///\endcode
|
605 |
605 |
void run(Node s) {
|
606 |
606 |
init();
|
607 |
607 |
addSource(s);
|
608 |
608 |
start();
|
609 |
609 |
}
|
610 |
610 |
|
611 |
611 |
///Finds the %DFS path between \c s and \c t.
|
612 |
612 |
|
613 |
613 |
///This method runs the %DFS algorithm from node \c s
|
614 |
614 |
///in order to compute the DFS path to node \c t
|
615 |
615 |
///(it stops searching when \c t is processed)
|
616 |
616 |
///
|
617 |
617 |
///\return \c true if \c t is reachable form \c s.
|
618 |
618 |
///
|
619 |
619 |
///\note Apart from the return value, <tt>d.run(s,t)</tt> is
|
620 |
620 |
///just a shortcut of the following code.
|
621 |
621 |
///\code
|
622 |
622 |
/// d.init();
|
623 |
623 |
/// d.addSource(s);
|
624 |
624 |
/// d.start(t);
|
625 |
625 |
///\endcode
|
626 |
626 |
bool run(Node s,Node t) {
|
627 |
627 |
init();
|
628 |
628 |
addSource(s);
|
629 |
629 |
start(t);
|
630 |
630 |
return reached(t);
|
631 |
631 |
}
|
632 |
632 |
|
633 |
633 |
///Runs the algorithm to visit all nodes in the digraph.
|
634 |
634 |
|
635 |
635 |
///This method runs the %DFS algorithm in order to compute the
|
636 |
636 |
///%DFS path to each node.
|
637 |
637 |
///
|
638 |
638 |
///The algorithm computes
|
639 |
639 |
///- the %DFS tree (forest),
|
640 |
640 |
///- the distance of each node from the root(s) in the %DFS tree.
|
641 |
641 |
///
|
642 |
642 |
///\note <tt>d.run()</tt> is just a shortcut of the following code.
|
643 |
643 |
///\code
|
644 |
644 |
/// d.init();
|
645 |
645 |
/// for (NodeIt n(digraph); n != INVALID; ++n) {
|
646 |
646 |
/// if (!d.reached(n)) {
|
647 |
647 |
/// d.addSource(n);
|
648 |
648 |
/// d.start();
|
649 |
649 |
/// }
|
650 |
650 |
/// }
|
651 |
651 |
///\endcode
|
652 |
652 |
void run() {
|
653 |
653 |
init();
|
654 |
654 |
for (NodeIt it(*G); it != INVALID; ++it) {
|
655 |
655 |
if (!reached(it)) {
|
656 |
656 |
addSource(it);
|
657 |
657 |
start();
|
658 |
658 |
}
|
659 |
659 |
}
|
660 |
660 |
}
|
661 |
661 |
|
662 |
662 |
///@}
|
663 |
663 |
|
664 |
664 |
///\name Query Functions
|
665 |
665 |
///The results of the DFS algorithm can be obtained using these
|
666 |
666 |
///functions.\n
|
667 |
667 |
///Either \ref run(Node) "run()" or \ref start() should be called
|
668 |
668 |
///before using them.
|
669 |
669 |
|
670 |
670 |
///@{
|
671 |
671 |
|
672 |
672 |
///The DFS path to a node.
|
673 |
673 |
|
674 |
674 |
///Returns the DFS path to a node.
|
675 |
675 |
///
|
676 |
676 |
///\warning \c t should be reached from the root(s).
|
677 |
677 |
///
|
678 |
678 |
///\pre Either \ref run(Node) "run()" or \ref init()
|
679 |
679 |
///must be called before using this function.
|
680 |
680 |
Path path(Node t) const { return Path(*G, *_pred, t); }
|
681 |
681 |
|
682 |
682 |
///The distance of a node from the root(s).
|
683 |
683 |
|
684 |
684 |
///Returns the distance of a node from the root(s).
|
685 |
685 |
///
|
686 |
686 |
///\warning If node \c v is not reached from the root(s), then
|
687 |
687 |
///the return value of this function is undefined.
|
688 |
688 |
///
|
689 |
689 |
///\pre Either \ref run(Node) "run()" or \ref init()
|
690 |
690 |
///must be called before using this function.
|
691 |
691 |
int dist(Node v) const { return (*_dist)[v]; }
|
692 |
692 |
|
693 |
693 |
///Returns the 'previous arc' of the %DFS tree for a node.
|
694 |
694 |
|
695 |
695 |
///This function returns the 'previous arc' of the %DFS tree for the
|
696 |
696 |
///node \c v, i.e. it returns the last arc of a %DFS path from a
|
697 |
697 |
///root to \c v. It is \c INVALID if \c v is not reached from the
|
698 |
698 |
///root(s) or if \c v is a root.
|
699 |
699 |
///
|
700 |
700 |
///The %DFS tree used here is equal to the %DFS tree used in
|
701 |
701 |
///\ref predNode().
|
702 |
702 |
///
|
703 |
703 |
///\pre Either \ref run(Node) "run()" or \ref init()
|
704 |
704 |
///must be called before using this function.
|
705 |
705 |
Arc predArc(Node v) const { return (*_pred)[v];}
|
706 |
706 |
|
707 |
707 |
///Returns the 'previous node' of the %DFS tree.
|
708 |
708 |
|
709 |
709 |
///This function returns the 'previous node' of the %DFS
|
710 |
710 |
///tree for the node \c v, i.e. it returns the last but one node
|
711 |
711 |
///from a %DFS path from a root to \c v. It is \c INVALID
|
712 |
712 |
///if \c v is not reached from the root(s) or if \c v is a root.
|
713 |
713 |
///
|
714 |
714 |
///The %DFS tree used here is equal to the %DFS tree used in
|
715 |
715 |
///\ref predArc().
|
716 |
716 |
///
|
717 |
717 |
///\pre Either \ref run(Node) "run()" or \ref init()
|
718 |
718 |
///must be called before using this function.
|
719 |
719 |
Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
|
720 |
720 |
G->source((*_pred)[v]); }
|
721 |
721 |
|
722 |
722 |
///\brief Returns a const reference to the node map that stores the
|
723 |
723 |
///distances of the nodes.
|
724 |
724 |
///
|
725 |
725 |
///Returns a const reference to the node map that stores the
|
726 |
726 |
///distances of the nodes calculated by the algorithm.
|
727 |
727 |
///
|
728 |
728 |
///\pre Either \ref run(Node) "run()" or \ref init()
|
729 |
729 |
///must be called before using this function.
|
730 |
730 |
const DistMap &distMap() const { return *_dist;}
|
731 |
731 |
|
732 |
732 |
///\brief Returns a const reference to the node map that stores the
|
733 |
733 |
///predecessor arcs.
|
734 |
734 |
///
|
735 |
735 |
///Returns a const reference to the node map that stores the predecessor
|
736 |
736 |
///arcs, which form the DFS tree.
|
737 |
737 |
///
|
738 |
738 |
///\pre Either \ref run(Node) "run()" or \ref init()
|
739 |
739 |
///must be called before using this function.
|
740 |
740 |
const PredMap &predMap() const { return *_pred;}
|
741 |
741 |
|
742 |
742 |
///Checks if a node is reached from the root(s).
|
743 |
743 |
|
744 |
744 |
///Returns \c true if \c v is reached from the root(s).
|
745 |
745 |
///
|
746 |
746 |
///\pre Either \ref run(Node) "run()" or \ref init()
|
747 |
747 |
///must be called before using this function.
|
748 |
748 |
bool reached(Node v) const { return (*_reached)[v]; }
|
749 |
749 |
|
750 |
750 |
///@}
|
751 |
751 |
};
|
752 |
752 |
|
... |
... |
@@ -1320,318 +1320,318 @@
|
1320 |
1320 |
}
|
1321 |
1321 |
};
|
1322 |
1322 |
/// \brief \ref named-templ-param "Named parameter" for setting
|
1323 |
1323 |
/// ReachedMap type.
|
1324 |
1324 |
///
|
1325 |
1325 |
/// \ref named-templ-param "Named parameter" for setting ReachedMap type.
|
1326 |
1326 |
template <class T>
|
1327 |
1327 |
struct SetReachedMap : public DfsVisit< Digraph, Visitor,
|
1328 |
1328 |
SetReachedMapTraits<T> > {
|
1329 |
1329 |
typedef DfsVisit< Digraph, Visitor, SetReachedMapTraits<T> > Create;
|
1330 |
1330 |
};
|
1331 |
1331 |
///@}
|
1332 |
1332 |
|
1333 |
1333 |
public:
|
1334 |
1334 |
|
1335 |
1335 |
/// \brief Constructor.
|
1336 |
1336 |
///
|
1337 |
1337 |
/// Constructor.
|
1338 |
1338 |
///
|
1339 |
1339 |
/// \param digraph The digraph the algorithm runs on.
|
1340 |
1340 |
/// \param visitor The visitor object of the algorithm.
|
1341 |
1341 |
DfsVisit(const Digraph& digraph, Visitor& visitor)
|
1342 |
1342 |
: _digraph(&digraph), _visitor(&visitor),
|
1343 |
1343 |
_reached(0), local_reached(false) {}
|
1344 |
1344 |
|
1345 |
1345 |
/// \brief Destructor.
|
1346 |
1346 |
~DfsVisit() {
|
1347 |
1347 |
if(local_reached) delete _reached;
|
1348 |
1348 |
}
|
1349 |
1349 |
|
1350 |
1350 |
/// \brief Sets the map that indicates which nodes are reached.
|
1351 |
1351 |
///
|
1352 |
1352 |
/// Sets the map that indicates which nodes are reached.
|
1353 |
1353 |
/// If you don't use this function before calling \ref run(Node) "run()"
|
1354 |
1354 |
/// or \ref init(), an instance will be allocated automatically.
|
1355 |
1355 |
/// The destructor deallocates this automatically allocated map,
|
1356 |
1356 |
/// of course.
|
1357 |
1357 |
/// \return <tt> (*this) </tt>
|
1358 |
1358 |
DfsVisit &reachedMap(ReachedMap &m) {
|
1359 |
1359 |
if(local_reached) {
|
1360 |
1360 |
delete _reached;
|
1361 |
1361 |
local_reached=false;
|
1362 |
1362 |
}
|
1363 |
1363 |
_reached = &m;
|
1364 |
1364 |
return *this;
|
1365 |
1365 |
}
|
1366 |
1366 |
|
1367 |
1367 |
public:
|
1368 |
1368 |
|
1369 |
1369 |
/// \name Execution Control
|
1370 |
1370 |
/// The simplest way to execute the DFS algorithm is to use one of the
|
1371 |
1371 |
/// member functions called \ref run(Node) "run()".\n
|
1372 |
1372 |
/// If you need more control on the execution, first you have to call
|
1373 |
1373 |
/// \ref init(), then you can add a source node with \ref addSource()
|
1374 |
1374 |
/// and perform the actual computation with \ref start().
|
1375 |
1375 |
/// This procedure can be repeated if there are nodes that have not
|
1376 |
1376 |
/// been reached.
|
1377 |
1377 |
|
1378 |
1378 |
/// @{
|
1379 |
1379 |
|
1380 |
1380 |
/// \brief Initializes the internal data structures.
|
1381 |
1381 |
///
|
1382 |
1382 |
/// Initializes the internal data structures.
|
1383 |
1383 |
void init() {
|
1384 |
1384 |
create_maps();
|
1385 |
1385 |
_stack.resize(countNodes(*_digraph));
|
1386 |
1386 |
_stack_head = -1;
|
1387 |
1387 |
for (NodeIt u(*_digraph) ; u != INVALID ; ++u) {
|
1388 |
1388 |
_reached->set(u, false);
|
1389 |
1389 |
}
|
1390 |
1390 |
}
|
1391 |
1391 |
|
1392 |
1392 |
/// \brief Adds a new source node.
|
1393 |
1393 |
///
|
1394 |
1394 |
/// Adds a new source node to the set of nodes to be processed.
|
1395 |
1395 |
///
|
1396 |
1396 |
/// \pre The stack must be empty. Otherwise the algorithm gives
|
1397 |
1397 |
/// wrong results. (One of the outgoing arcs of all the source nodes
|
1398 |
1398 |
/// except for the last one will not be visited and distances will
|
1399 |
1399 |
/// also be wrong.)
|
1400 |
1400 |
void addSource(Node s)
|
1401 |
1401 |
{
|
1402 |
1402 |
LEMON_DEBUG(emptyQueue(), "The stack is not empty.");
|
1403 |
1403 |
if(!(*_reached)[s]) {
|
1404 |
1404 |
_reached->set(s,true);
|
1405 |
1405 |
_visitor->start(s);
|
1406 |
1406 |
_visitor->reach(s);
|
1407 |
1407 |
Arc e;
|
1408 |
1408 |
_digraph->firstOut(e, s);
|
1409 |
1409 |
if (e != INVALID) {
|
1410 |
1410 |
_stack[++_stack_head] = e;
|
1411 |
1411 |
} else {
|
1412 |
1412 |
_visitor->leave(s);
|
1413 |
1413 |
_visitor->stop(s);
|
1414 |
1414 |
}
|
1415 |
1415 |
}
|
1416 |
1416 |
}
|
1417 |
1417 |
|
1418 |
1418 |
/// \brief Processes the next arc.
|
1419 |
1419 |
///
|
1420 |
1420 |
/// Processes the next arc.
|
1421 |
1421 |
///
|
1422 |
1422 |
/// \return The processed arc.
|
1423 |
1423 |
///
|
1424 |
1424 |
/// \pre The stack must not be empty.
|
1425 |
1425 |
Arc processNextArc() {
|
1426 |
1426 |
Arc e = _stack[_stack_head];
|
1427 |
1427 |
Node m = _digraph->target(e);
|
1428 |
1428 |
if(!(*_reached)[m]) {
|
1429 |
1429 |
_visitor->discover(e);
|
1430 |
1430 |
_visitor->reach(m);
|
1431 |
1431 |
_reached->set(m, true);
|
1432 |
1432 |
_digraph->firstOut(_stack[++_stack_head], m);
|
1433 |
1433 |
} else {
|
1434 |
1434 |
_visitor->examine(e);
|
1435 |
1435 |
m = _digraph->source(e);
|
1436 |
1436 |
_digraph->nextOut(_stack[_stack_head]);
|
1437 |
1437 |
}
|
1438 |
1438 |
while (_stack_head>=0 && _stack[_stack_head] == INVALID) {
|
1439 |
1439 |
_visitor->leave(m);
|
1440 |
1440 |
--_stack_head;
|
1441 |
1441 |
if (_stack_head >= 0) {
|
1442 |
1442 |
_visitor->backtrack(_stack[_stack_head]);
|
1443 |
1443 |
m = _digraph->source(_stack[_stack_head]);
|
1444 |
1444 |
_digraph->nextOut(_stack[_stack_head]);
|
1445 |
1445 |
} else {
|
1446 |
1446 |
_visitor->stop(m);
|
1447 |
1447 |
}
|
1448 |
1448 |
}
|
1449 |
1449 |
return e;
|
1450 |
1450 |
}
|
1451 |
1451 |
|
1452 |
1452 |
/// \brief Next arc to be processed.
|
1453 |
1453 |
///
|
1454 |
1454 |
/// Next arc to be processed.
|
1455 |
1455 |
///
|
1456 |
1456 |
/// \return The next arc to be processed or INVALID if the stack is
|
1457 |
1457 |
/// empty.
|
1458 |
1458 |
Arc nextArc() const {
|
1459 |
1459 |
return _stack_head >= 0 ? _stack[_stack_head] : INVALID;
|
1460 |
1460 |
}
|
1461 |
1461 |
|
1462 |
1462 |
/// \brief Returns \c false if there are nodes
|
1463 |
1463 |
/// to be processed.
|
1464 |
1464 |
///
|
1465 |
1465 |
/// Returns \c false if there are nodes
|
1466 |
1466 |
/// to be processed in the queue (stack).
|
1467 |
1467 |
bool emptyQueue() const { return _stack_head < 0; }
|
1468 |
1468 |
|
1469 |
1469 |
/// \brief Returns the number of the nodes to be processed.
|
1470 |
1470 |
///
|
1471 |
1471 |
/// Returns the number of the nodes to be processed in the queue (stack).
|
1472 |
1472 |
int queueSize() const { return _stack_head + 1; }
|
1473 |
1473 |
|
1474 |
1474 |
/// \brief Executes the algorithm.
|
1475 |
1475 |
///
|
1476 |
1476 |
/// Executes the algorithm.
|
1477 |
1477 |
///
|
1478 |
1478 |
/// This method runs the %DFS algorithm from the root node
|
1479 |
1479 |
/// in order to compute the %DFS path to each node.
|
1480 |
1480 |
///
|
1481 |
1481 |
/// The algorithm computes
|
1482 |
1482 |
/// - the %DFS tree,
|
1483 |
1483 |
/// - the distance of each node from the root in the %DFS tree.
|
1484 |
1484 |
///
|
1485 |
1485 |
/// \pre init() must be called and a root node should be
|
1486 |
1486 |
/// added with addSource() before using this function.
|
1487 |
1487 |
///
|
1488 |
1488 |
/// \note <tt>d.start()</tt> is just a shortcut of the following code.
|
1489 |
1489 |
/// \code
|
1490 |
1490 |
/// while ( !d.emptyQueue() ) {
|
1491 |
1491 |
/// d.processNextArc();
|
1492 |
1492 |
/// }
|
1493 |
1493 |
/// \endcode
|
1494 |
1494 |
void start() {
|
1495 |
1495 |
while ( !emptyQueue() ) processNextArc();
|
1496 |
1496 |
}
|
1497 |
1497 |
|
1498 |
1498 |
/// \brief Executes the algorithm until the given target node is reached.
|
1499 |
1499 |
///
|
1500 |
1500 |
/// Executes the algorithm until the given target node is reached.
|
1501 |
1501 |
///
|
1502 |
1502 |
/// This method runs the %DFS algorithm from the root node
|
1503 |
1503 |
/// in order to compute the DFS path to \c t.
|
1504 |
1504 |
///
|
1505 |
1505 |
/// The algorithm computes
|
1506 |
1506 |
/// - the %DFS path to \c t,
|
1507 |
1507 |
/// - the distance of \c t from the root in the %DFS tree.
|
1508 |
1508 |
///
|
1509 |
1509 |
/// \pre init() must be called and a root node should be added
|
1510 |
1510 |
/// with addSource() before using this function.
|
1511 |
1511 |
void start(Node t) {
|
1512 |
|
while ( !emptyQueue() && _digraph->target(_stack[_stack_head]) != t )
|
|
1512 |
while ( !emptyQueue() && !(*_reached)[t] )
|
1513 |
1513 |
processNextArc();
|
1514 |
1514 |
}
|
1515 |
1515 |
|
1516 |
1516 |
/// \brief Executes the algorithm until a condition is met.
|
1517 |
1517 |
///
|
1518 |
1518 |
/// Executes the algorithm until a condition is met.
|
1519 |
1519 |
///
|
1520 |
1520 |
/// This method runs the %DFS algorithm from the root node
|
1521 |
1521 |
/// until an arc \c a with <tt>am[a]</tt> true is found.
|
1522 |
1522 |
///
|
1523 |
1523 |
/// \param am A \c bool (or convertible) arc map. The algorithm
|
1524 |
1524 |
/// will stop when it reaches an arc \c a with <tt>am[a]</tt> true.
|
1525 |
1525 |
///
|
1526 |
1526 |
/// \return The reached arc \c a with <tt>am[a]</tt> true or
|
1527 |
1527 |
/// \c INVALID if no such arc was found.
|
1528 |
1528 |
///
|
1529 |
1529 |
/// \pre init() must be called and a root node should be added
|
1530 |
1530 |
/// with addSource() before using this function.
|
1531 |
1531 |
///
|
1532 |
1532 |
/// \warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map,
|
1533 |
1533 |
/// not a node map.
|
1534 |
1534 |
template <typename AM>
|
1535 |
1535 |
Arc start(const AM &am) {
|
1536 |
1536 |
while ( !emptyQueue() && !am[_stack[_stack_head]] )
|
1537 |
1537 |
processNextArc();
|
1538 |
1538 |
return emptyQueue() ? INVALID : _stack[_stack_head];
|
1539 |
1539 |
}
|
1540 |
1540 |
|
1541 |
1541 |
/// \brief Runs the algorithm from the given source node.
|
1542 |
1542 |
///
|
1543 |
1543 |
/// This method runs the %DFS algorithm from node \c s.
|
1544 |
1544 |
/// in order to compute the DFS path to each node.
|
1545 |
1545 |
///
|
1546 |
1546 |
/// The algorithm computes
|
1547 |
1547 |
/// - the %DFS tree,
|
1548 |
1548 |
/// - the distance of each node from the root in the %DFS tree.
|
1549 |
1549 |
///
|
1550 |
1550 |
/// \note <tt>d.run(s)</tt> is just a shortcut of the following code.
|
1551 |
1551 |
///\code
|
1552 |
1552 |
/// d.init();
|
1553 |
1553 |
/// d.addSource(s);
|
1554 |
1554 |
/// d.start();
|
1555 |
1555 |
///\endcode
|
1556 |
1556 |
void run(Node s) {
|
1557 |
1557 |
init();
|
1558 |
1558 |
addSource(s);
|
1559 |
1559 |
start();
|
1560 |
1560 |
}
|
1561 |
1561 |
|
1562 |
1562 |
/// \brief Finds the %DFS path between \c s and \c t.
|
1563 |
1563 |
|
1564 |
1564 |
/// This method runs the %DFS algorithm from node \c s
|
1565 |
1565 |
/// in order to compute the DFS path to node \c t
|
1566 |
1566 |
/// (it stops searching when \c t is processed).
|
1567 |
1567 |
///
|
1568 |
1568 |
/// \return \c true if \c t is reachable form \c s.
|
1569 |
1569 |
///
|
1570 |
1570 |
/// \note Apart from the return value, <tt>d.run(s,t)</tt> is
|
1571 |
1571 |
/// just a shortcut of the following code.
|
1572 |
1572 |
///\code
|
1573 |
1573 |
/// d.init();
|
1574 |
1574 |
/// d.addSource(s);
|
1575 |
1575 |
/// d.start(t);
|
1576 |
1576 |
///\endcode
|
1577 |
1577 |
bool run(Node s,Node t) {
|
1578 |
1578 |
init();
|
1579 |
1579 |
addSource(s);
|
1580 |
1580 |
start(t);
|
1581 |
1581 |
return reached(t);
|
1582 |
1582 |
}
|
1583 |
1583 |
|
1584 |
1584 |
/// \brief Runs the algorithm to visit all nodes in the digraph.
|
1585 |
1585 |
|
1586 |
1586 |
/// This method runs the %DFS algorithm in order to
|
1587 |
1587 |
/// compute the %DFS path to each node.
|
1588 |
1588 |
///
|
1589 |
1589 |
/// The algorithm computes
|
1590 |
1590 |
/// - the %DFS tree (forest),
|
1591 |
1591 |
/// - the distance of each node from the root(s) in the %DFS tree.
|
1592 |
1592 |
///
|
1593 |
1593 |
/// \note <tt>d.run()</tt> is just a shortcut of the following code.
|
1594 |
1594 |
///\code
|
1595 |
1595 |
/// d.init();
|
1596 |
1596 |
/// for (NodeIt n(digraph); n != INVALID; ++n) {
|
1597 |
1597 |
/// if (!d.reached(n)) {
|
1598 |
1598 |
/// d.addSource(n);
|
1599 |
1599 |
/// d.start();
|
1600 |
1600 |
/// }
|
1601 |
1601 |
/// }
|
1602 |
1602 |
///\endcode
|
1603 |
1603 |
void run() {
|
1604 |
1604 |
init();
|
1605 |
1605 |
for (NodeIt it(*_digraph); it != INVALID; ++it) {
|
1606 |
1606 |
if (!reached(it)) {
|
1607 |
1607 |
addSource(it);
|
1608 |
1608 |
start();
|
1609 |
1609 |
}
|
1610 |
1610 |
}
|
1611 |
1611 |
}
|
1612 |
1612 |
|
1613 |
1613 |
///@}
|
1614 |
1614 |
|
1615 |
1615 |
/// \name Query Functions
|
1616 |
1616 |
/// The results of the DFS algorithm can be obtained using these
|
1617 |
1617 |
/// functions.\n
|
1618 |
1618 |
/// Either \ref run(Node) "run()" or \ref start() should be called
|
1619 |
1619 |
/// before using them.
|
1620 |
1620 |
|
1621 |
1621 |
///@{
|
1622 |
1622 |
|
1623 |
1623 |
/// \brief Checks if a node is reached from the root(s).
|
1624 |
1624 |
///
|
1625 |
1625 |
/// Returns \c true if \c v is reached from the root(s).
|
1626 |
1626 |
///
|
1627 |
1627 |
/// \pre Either \ref run(Node) "run()" or \ref init()
|
1628 |
1628 |
/// must be called before using this function.
|
1629 |
1629 |
bool reached(Node v) const { return (*_reached)[v]; }
|
1630 |
1630 |
|
1631 |
1631 |
///@}
|
1632 |
1632 |
|
1633 |
1633 |
};
|
1634 |
1634 |
|
1635 |
1635 |
} //END OF NAMESPACE LEMON
|
1636 |
1636 |
|
1637 |
1637 |
#endif
|