alpar@100: /* -*- C++ -*-
alpar@100:  *
alpar@100:  * This file is a part of LEMON, a generic C++ optimization library
alpar@100:  *
alpar@100:  * Copyright (C) 2003-2008
alpar@100:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@100:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
alpar@100:  *
alpar@100:  * Permission to use, modify and distribute this software is granted
alpar@100:  * provided that this copyright notice appears in all copies. For
alpar@100:  * precise terms see the accompanying LICENSE file.
alpar@100:  *
alpar@100:  * This software is provided "AS IS" with no warranty of any kind,
alpar@100:  * express or implied, and with no claim as to its suitability for any
alpar@100:  * purpose.
alpar@100:  *
alpar@100:  */
alpar@100: 
alpar@100: #ifndef LEMON_BFS_H
alpar@100: #define LEMON_BFS_H
alpar@100: 
alpar@100: ///\ingroup search
alpar@100: ///\file
alpar@100: ///\brief Bfs algorithm.
alpar@100: 
alpar@100: #include <lemon/list_graph.h>
alpar@100: #include <lemon/graph_utils.h>
alpar@100: #include <lemon/bits/path_dump.h>
alpar@100: #include <lemon/bits/invalid.h>
alpar@100: #include <lemon/error.h>
alpar@100: #include <lemon/maps.h>
alpar@100: 
alpar@100: namespace lemon {
alpar@100: 
alpar@100: 
alpar@100:   
alpar@100:   ///Default traits class of Bfs class.
alpar@100: 
alpar@100:   ///Default traits class of Bfs class.
kpeter@157:   ///\tparam GR Digraph type.
alpar@100:   template<class GR>
alpar@100:   struct BfsDefaultTraits
alpar@100:   {
alpar@100:     ///The digraph type the algorithm runs on. 
alpar@100:     typedef GR Digraph;
alpar@100:     ///\brief The type of the map that stores the last
alpar@100:     ///arcs of the shortest paths.
alpar@100:     /// 
alpar@100:     ///The type of the map that stores the last
alpar@100:     ///arcs of the shortest paths.
alpar@100:     ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100:     ///
alpar@100:     typedef typename Digraph::template NodeMap<typename GR::Arc> PredMap;
alpar@100:     ///Instantiates a PredMap.
alpar@100:  
alpar@100:     ///This function instantiates a \ref PredMap. 
alpar@100:     ///\param G is the digraph, to which we would like to define the PredMap.
alpar@100:     ///\todo The digraph alone may be insufficient to initialize
alpar@100:     static PredMap *createPredMap(const GR &G) 
alpar@100:     {
alpar@100:       return new PredMap(G);
alpar@100:     }
alpar@100:     ///The type of the map that indicates which nodes are processed.
alpar@100:  
alpar@100:     ///The type of the map that indicates which nodes are processed.
alpar@100:     ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100:     ///\todo named parameter to set this type, function to read and write.
alpar@100:     typedef NullMap<typename Digraph::Node,bool> ProcessedMap;
alpar@100:     ///Instantiates a ProcessedMap.
alpar@100:  
alpar@100:     ///This function instantiates a \ref ProcessedMap. 
alpar@100:     ///\param g is the digraph, to which
alpar@100:     ///we would like to define the \ref ProcessedMap
alpar@100: #ifdef DOXYGEN
alpar@100:     static ProcessedMap *createProcessedMap(const GR &g)
alpar@100: #else
alpar@100:     static ProcessedMap *createProcessedMap(const GR &)
alpar@100: #endif
alpar@100:     {
alpar@100:       return new ProcessedMap();
alpar@100:     }
alpar@100:     ///The type of the map that indicates which nodes are reached.
alpar@100:  
alpar@100:     ///The type of the map that indicates which nodes are reached.
alpar@100:     ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100:     ///\todo named parameter to set this type, function to read and write.
alpar@100:     typedef typename Digraph::template NodeMap<bool> ReachedMap;
alpar@100:     ///Instantiates a ReachedMap.
alpar@100:  
alpar@100:     ///This function instantiates a \ref ReachedMap. 
alpar@100:     ///\param G is the digraph, to which
alpar@100:     ///we would like to define the \ref ReachedMap.
alpar@100:     static ReachedMap *createReachedMap(const GR &G)
alpar@100:     {
alpar@100:       return new ReachedMap(G);
alpar@100:     }
alpar@100:     ///The type of the map that stores the dists of the nodes.
alpar@100:  
alpar@100:     ///The type of the map that stores the dists of the nodes.
alpar@100:     ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100:     ///
alpar@100:     typedef typename Digraph::template NodeMap<int> DistMap;
alpar@100:     ///Instantiates a DistMap.
alpar@100:  
alpar@100:     ///This function instantiates a \ref DistMap. 
alpar@100:     ///\param G is the digraph, to which we would like to define the \ref DistMap
alpar@100:     static DistMap *createDistMap(const GR &G)
alpar@100:     {
alpar@100:       return new DistMap(G);
alpar@100:     }
alpar@100:   };
alpar@100:   
alpar@100:   ///%BFS algorithm class.
alpar@100:   
alpar@100:   ///\ingroup search
alpar@100:   ///This class provides an efficient implementation of the %BFS algorithm.
alpar@100:   ///
kpeter@157:   ///\tparam GR The digraph type the algorithm runs on. The default value is
alpar@100:   ///\ref ListDigraph. The value of GR is not used directly by Bfs, it
alpar@100:   ///is only passed to \ref BfsDefaultTraits.
kpeter@157:   ///\tparam TR Traits class to set various data types used by the algorithm.
alpar@100:   ///The default traits class is
alpar@100:   ///\ref BfsDefaultTraits "BfsDefaultTraits<GR>".
alpar@100:   ///See \ref BfsDefaultTraits for the documentation of
alpar@100:   ///a Bfs traits class.
alpar@100: 
alpar@100: #ifdef DOXYGEN
alpar@100:   template <typename GR,
alpar@100: 	    typename TR>
alpar@100: #else
alpar@100:   template <typename GR=ListDigraph,
alpar@100: 	    typename TR=BfsDefaultTraits<GR> >
alpar@100: #endif
alpar@100:   class Bfs {
alpar@100:   public:
alpar@100:     /**
alpar@100:      * \brief \ref Exception for uninitialized parameters.
alpar@100:      *
alpar@100:      * This error represents problems in the initialization
alpar@100:      * of the parameters of the algorithms.
alpar@100:      */
alpar@100:     class UninitializedParameter : public lemon::UninitializedParameter {
alpar@100:     public:
alpar@100:       virtual const char* what() const throw() {
alpar@100: 	return "lemon::Bfs::UninitializedParameter";
alpar@100:       }
alpar@100:     };
alpar@100: 
alpar@100:     typedef TR Traits;
alpar@100:     ///The type of the underlying digraph.
alpar@100:     typedef typename TR::Digraph Digraph;
alpar@100:     
alpar@100:     ///\brief The type of the map that stores the last
alpar@100:     ///arcs of the shortest paths.
alpar@100:     typedef typename TR::PredMap PredMap;
alpar@100:     ///The type of the map indicating which nodes are reached.
alpar@100:     typedef typename TR::ReachedMap ReachedMap;
alpar@100:     ///The type of the map indicating which nodes are processed.
alpar@100:     typedef typename TR::ProcessedMap ProcessedMap;
alpar@100:     ///The type of the map that stores the dists of the nodes.
alpar@100:     typedef typename TR::DistMap DistMap;
alpar@100:   private:
alpar@100: 
alpar@100:     typedef typename Digraph::Node Node;
alpar@100:     typedef typename Digraph::NodeIt NodeIt;
alpar@100:     typedef typename Digraph::Arc Arc;
alpar@100:     typedef typename Digraph::OutArcIt OutArcIt;
alpar@100: 
alpar@100:     /// Pointer to the underlying digraph.
alpar@100:     const Digraph *G;
alpar@100:     ///Pointer to the map of predecessors arcs.
alpar@100:     PredMap *_pred;
alpar@100:     ///Indicates if \ref _pred is locally allocated (\c true) or not.
alpar@100:     bool local_pred;
alpar@100:     ///Pointer to the map of distances.
alpar@100:     DistMap *_dist;
alpar@100:     ///Indicates if \ref _dist is locally allocated (\c true) or not.
alpar@100:     bool local_dist;
alpar@100:     ///Pointer to the map of reached status of the nodes.
alpar@100:     ReachedMap *_reached;
alpar@100:     ///Indicates if \ref _reached is locally allocated (\c true) or not.
alpar@100:     bool local_reached;
alpar@100:     ///Pointer to the map of processed status of the nodes.
alpar@100:     ProcessedMap *_processed;
alpar@100:     ///Indicates if \ref _processed is locally allocated (\c true) or not.
alpar@100:     bool local_processed;
alpar@100: 
alpar@100:     std::vector<typename Digraph::Node> _queue;
alpar@100:     int _queue_head,_queue_tail,_queue_next_dist;
alpar@100:     int _curr_dist;
alpar@100: 
alpar@100:     ///Creates the maps if necessary.
alpar@100:     
alpar@100:     ///\todo Better memory allocation (instead of new).
alpar@100:     void create_maps() 
alpar@100:     {
alpar@100:       if(!_pred) {
alpar@100: 	local_pred = true;
alpar@100: 	_pred = Traits::createPredMap(*G);
alpar@100:       }
alpar@100:       if(!_dist) {
alpar@100: 	local_dist = true;
alpar@100: 	_dist = Traits::createDistMap(*G);
alpar@100:       }
alpar@100:       if(!_reached) {
alpar@100: 	local_reached = true;
alpar@100: 	_reached = Traits::createReachedMap(*G);
alpar@100:       }
alpar@100:       if(!_processed) {
alpar@100: 	local_processed = true;
alpar@100: 	_processed = Traits::createProcessedMap(*G);
alpar@100:       }
alpar@100:     }
alpar@100: 
alpar@100:   protected:
alpar@100:     
alpar@100:     Bfs() {}
alpar@100:     
alpar@100:   public:
alpar@100:  
alpar@100:     typedef Bfs Create;
alpar@100: 
alpar@100:     ///\name Named template parameters
alpar@100: 
alpar@100:     ///@{
alpar@100: 
alpar@100:     template <class T>
alpar@100:     struct DefPredMapTraits : public Traits {
alpar@100:       typedef T PredMap;
alpar@100:       static PredMap *createPredMap(const Digraph &) 
alpar@100:       {
alpar@100: 	throw UninitializedParameter();
alpar@100:       }
alpar@100:     };
alpar@100:     ///\brief \ref named-templ-param "Named parameter" for setting
alpar@100:     ///PredMap type
alpar@100:     ///
alpar@100:     ///\ref named-templ-param "Named parameter" for setting PredMap type
alpar@100:     ///
alpar@100:     template <class T>
alpar@100:     struct DefPredMap : public Bfs< Digraph, DefPredMapTraits<T> > { 
alpar@100:       typedef Bfs< Digraph, DefPredMapTraits<T> > Create;
alpar@100:     };
alpar@100:     
alpar@100:     template <class T>
alpar@100:     struct DefDistMapTraits : public Traits {
alpar@100:       typedef T DistMap;
alpar@100:       static DistMap *createDistMap(const Digraph &) 
alpar@100:       {
alpar@100: 	throw UninitializedParameter();
alpar@100:       }
alpar@100:     };
alpar@100:     ///\brief \ref named-templ-param "Named parameter" for setting
alpar@100:     ///DistMap type
alpar@100:     ///
alpar@100:     ///\ref named-templ-param "Named parameter" for setting DistMap type
alpar@100:     ///
alpar@100:     template <class T>
alpar@100:     struct DefDistMap : public Bfs< Digraph, DefDistMapTraits<T> > { 
alpar@100:       typedef Bfs< Digraph, DefDistMapTraits<T> > Create;
alpar@100:     };
alpar@100:     
alpar@100:     template <class T>
alpar@100:     struct DefReachedMapTraits : public Traits {
alpar@100:       typedef T ReachedMap;
alpar@100:       static ReachedMap *createReachedMap(const Digraph &) 
alpar@100:       {
alpar@100: 	throw UninitializedParameter();
alpar@100:       }
alpar@100:     };
alpar@100:     ///\brief \ref named-templ-param "Named parameter" for setting
alpar@100:     ///ReachedMap type
alpar@100:     ///
alpar@100:     ///\ref named-templ-param "Named parameter" for setting ReachedMap type
alpar@100:     ///
alpar@100:     template <class T>
alpar@100:     struct DefReachedMap : public Bfs< Digraph, DefReachedMapTraits<T> > { 
alpar@100:       typedef Bfs< Digraph, DefReachedMapTraits<T> > Create;
alpar@100:     };
alpar@100:     
alpar@100:     template <class T>
alpar@100:     struct DefProcessedMapTraits : public Traits {
alpar@100:       typedef T ProcessedMap;
alpar@100:       static ProcessedMap *createProcessedMap(const Digraph &) 
alpar@100:       {
alpar@100: 	throw UninitializedParameter();
alpar@100:       }
alpar@100:     };
alpar@100:     ///\brief \ref named-templ-param "Named parameter" for setting
alpar@100:     ///ProcessedMap type
alpar@100:     ///
alpar@100:     ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
alpar@100:     ///
alpar@100:     template <class T>
alpar@100:     struct DefProcessedMap : public Bfs< Digraph, DefProcessedMapTraits<T> > {
alpar@100:       typedef Bfs< Digraph, DefProcessedMapTraits<T> > Create;
alpar@100:     };
alpar@100:     
alpar@100:     struct DefDigraphProcessedMapTraits : public Traits {
alpar@100:       typedef typename Digraph::template NodeMap<bool> ProcessedMap;
alpar@100:       static ProcessedMap *createProcessedMap(const Digraph &G) 
alpar@100:       {
alpar@100: 	return new ProcessedMap(G);
alpar@100:       }
alpar@100:     };
alpar@100:     ///\brief \ref named-templ-param "Named parameter"
alpar@100:     ///for setting the ProcessedMap type to be Digraph::NodeMap<bool>.
alpar@100:     ///
alpar@100:     ///\ref named-templ-param "Named parameter"
alpar@100:     ///for setting the ProcessedMap type to be Digraph::NodeMap<bool>.
alpar@100:     ///If you don't set it explicitly, it will be automatically allocated.
alpar@100:     template <class T>
alpar@100:     struct DefProcessedMapToBeDefaultMap :
alpar@100:       public Bfs< Digraph, DefDigraphProcessedMapTraits> { 
alpar@100:       typedef Bfs< Digraph, DefDigraphProcessedMapTraits> Create;
alpar@100:     };
alpar@100:     
alpar@100:     ///@}
alpar@100: 
alpar@100:   public:      
alpar@100:     
alpar@100:     ///Constructor.
alpar@100:     
alpar@100:     ///\param _G the digraph the algorithm will run on.
alpar@100:     ///
alpar@100:     Bfs(const Digraph& _G) :
alpar@100:       G(&_G),
alpar@100:       _pred(NULL), local_pred(false),
alpar@100:       _dist(NULL), local_dist(false),
alpar@100:       _reached(NULL), local_reached(false),
alpar@100:       _processed(NULL), local_processed(false)
alpar@100:     { }
alpar@100:     
alpar@100:     ///Destructor.
alpar@100:     ~Bfs() 
alpar@100:     {
alpar@100:       if(local_pred) delete _pred;
alpar@100:       if(local_dist) delete _dist;
alpar@100:       if(local_reached) delete _reached;
alpar@100:       if(local_processed) delete _processed;
alpar@100:     }
alpar@100: 
alpar@100:     ///Sets the map storing the predecessor arcs.
alpar@100: 
alpar@100:     ///Sets the map storing the predecessor arcs.
alpar@100:     ///If you don't use this function before calling \ref run(),
alpar@100:     ///it will allocate one. The destructor deallocates this
alpar@100:     ///automatically allocated map, of course.
alpar@100:     ///\return <tt> (*this) </tt>
alpar@100:     Bfs &predMap(PredMap &m) 
alpar@100:     {
alpar@100:       if(local_pred) {
alpar@100: 	delete _pred;
alpar@100: 	local_pred=false;
alpar@100:       }
alpar@100:       _pred = &m;
alpar@100:       return *this;
alpar@100:     }
alpar@100: 
alpar@100:     ///Sets the map indicating the reached nodes.
alpar@100: 
alpar@100:     ///Sets the map indicating the reached nodes.
alpar@100:     ///If you don't use this function before calling \ref run(),
alpar@100:     ///it will allocate one. The destructor deallocates this
alpar@100:     ///automatically allocated map, of course.
alpar@100:     ///\return <tt> (*this) </tt>
alpar@100:     Bfs &reachedMap(ReachedMap &m) 
alpar@100:     {
alpar@100:       if(local_reached) {
alpar@100: 	delete _reached;
alpar@100: 	local_reached=false;
alpar@100:       }
alpar@100:       _reached = &m;
alpar@100:       return *this;
alpar@100:     }
alpar@100: 
alpar@100:     ///Sets the map indicating the processed nodes.
alpar@100: 
alpar@100:     ///Sets the map indicating the processed nodes.
alpar@100:     ///If you don't use this function before calling \ref run(),
alpar@100:     ///it will allocate one. The destructor deallocates this
alpar@100:     ///automatically allocated map, of course.
alpar@100:     ///\return <tt> (*this) </tt>
alpar@100:     Bfs &processedMap(ProcessedMap &m) 
alpar@100:     {
alpar@100:       if(local_processed) {
alpar@100: 	delete _processed;
alpar@100: 	local_processed=false;
alpar@100:       }
alpar@100:       _processed = &m;
alpar@100:       return *this;
alpar@100:     }
alpar@100: 
alpar@100:     ///Sets the map storing the distances calculated by the algorithm.
alpar@100: 
alpar@100:     ///Sets the map storing the distances calculated by the algorithm.
alpar@100:     ///If you don't use this function before calling \ref run(),
alpar@100:     ///it will allocate one. The destructor deallocates this
alpar@100:     ///automatically allocated map, of course.
alpar@100:     ///\return <tt> (*this) </tt>
alpar@100:     Bfs &distMap(DistMap &m) 
alpar@100:     {
alpar@100:       if(local_dist) {
alpar@100: 	delete _dist;
alpar@100: 	local_dist=false;
alpar@100:       }
alpar@100:       _dist = &m;
alpar@100:       return *this;
alpar@100:     }
alpar@100: 
alpar@100:   public:
alpar@100:     ///\name Execution control
alpar@100:     ///The simplest way to execute the algorithm is to use
alpar@100:     ///one of the member functions called \c run(...).
alpar@100:     ///\n
alpar@100:     ///If you need more control on the execution,
alpar@100:     ///first you must call \ref init(), then you can add several source nodes
alpar@100:     ///with \ref addSource().
alpar@100:     ///Finally \ref start() will perform the actual path
alpar@100:     ///computation.
alpar@100: 
alpar@100:     ///@{
alpar@100: 
alpar@100:     ///\brief Initializes the internal data structures.
alpar@100:     ///
alpar@100:     ///Initializes the internal data structures.
alpar@100:     ///
alpar@100:     void init()
alpar@100:     {
alpar@100:       create_maps();
alpar@100:       _queue.resize(countNodes(*G));
alpar@100:       _queue_head=_queue_tail=0;
alpar@100:       _curr_dist=1;
alpar@100:       for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
alpar@100: 	_pred->set(u,INVALID);
alpar@100: 	_reached->set(u,false);
alpar@100: 	_processed->set(u,false);
alpar@100:       }
alpar@100:     }
alpar@100:     
alpar@100:     ///Adds a new source node.
alpar@100: 
alpar@100:     ///Adds a new source node to the set of nodes to be processed.
alpar@100:     ///
alpar@100:     void addSource(Node s)
alpar@100:     {
alpar@100:       if(!(*_reached)[s])
alpar@100: 	{
alpar@100: 	  _reached->set(s,true);
alpar@100: 	  _pred->set(s,INVALID);
alpar@100: 	  _dist->set(s,0);
alpar@100: 	  _queue[_queue_head++]=s;
alpar@100: 	  _queue_next_dist=_queue_head;
alpar@100: 	}
alpar@100:     }
alpar@100:     
alpar@100:     ///Processes the next node.
alpar@100: 
alpar@100:     ///Processes the next node.
alpar@100:     ///
alpar@100:     ///\return The processed node.
alpar@100:     ///
alpar@100:     ///\warning The queue must not be empty!
alpar@100:     Node processNextNode()
alpar@100:     {
alpar@100:       if(_queue_tail==_queue_next_dist) {
alpar@100: 	_curr_dist++;
alpar@100: 	_queue_next_dist=_queue_head;
alpar@100:       }
alpar@100:       Node n=_queue[_queue_tail++];
alpar@100:       _processed->set(n,true);
alpar@100:       Node m;
alpar@100:       for(OutArcIt e(*G,n);e!=INVALID;++e)
alpar@100: 	if(!(*_reached)[m=G->target(e)]) {
alpar@100: 	  _queue[_queue_head++]=m;
alpar@100: 	  _reached->set(m,true);
alpar@100: 	  _pred->set(m,e);
alpar@100: 	  _dist->set(m,_curr_dist);
alpar@100: 	}
alpar@100:       return n;
alpar@100:     }
alpar@100: 
alpar@100:     ///Processes the next node.
alpar@100: 
alpar@100:     ///Processes the next node. And checks that the given target node
alpar@100:     ///is reached. If the target node is reachable from the processed
alpar@100:     ///node then the reached parameter will be set true. The reached
alpar@100:     ///parameter should be initially false.
alpar@100:     ///
alpar@100:     ///\param target The target node.
alpar@100:     ///\retval reach Indicates that the target node is reached.
alpar@100:     ///\return The processed node.
alpar@100:     ///
alpar@100:     ///\warning The queue must not be empty!
alpar@100:     Node processNextNode(Node target, bool& reach)
alpar@100:     {
alpar@100:       if(_queue_tail==_queue_next_dist) {
alpar@100: 	_curr_dist++;
alpar@100: 	_queue_next_dist=_queue_head;
alpar@100:       }
alpar@100:       Node n=_queue[_queue_tail++];
alpar@100:       _processed->set(n,true);
alpar@100:       Node m;
alpar@100:       for(OutArcIt e(*G,n);e!=INVALID;++e)
alpar@100: 	if(!(*_reached)[m=G->target(e)]) {
alpar@100: 	  _queue[_queue_head++]=m;
alpar@100: 	  _reached->set(m,true);
alpar@100: 	  _pred->set(m,e);
alpar@100: 	  _dist->set(m,_curr_dist);
alpar@100:           reach = reach || (target == m);
alpar@100: 	}
alpar@100:       return n;
alpar@100:     }
alpar@100: 
alpar@100:     ///Processes the next node.
alpar@100: 
alpar@100:     ///Processes the next node. And checks that at least one of
alpar@100:     ///reached node has true value in the \c nm node map. If one node
alpar@100:     ///with true value is reachable from the processed node then the
alpar@100:     ///rnode parameter will be set to the first of such nodes.
alpar@100:     ///
alpar@100:     ///\param nm The node map of possible targets.
alpar@100:     ///\retval rnode The reached target node.
alpar@100:     ///\return The processed node.
alpar@100:     ///
alpar@100:     ///\warning The queue must not be empty!
alpar@100:     template<class NM>
alpar@100:     Node processNextNode(const NM& nm, Node& rnode)
alpar@100:     {
alpar@100:       if(_queue_tail==_queue_next_dist) {
alpar@100: 	_curr_dist++;
alpar@100: 	_queue_next_dist=_queue_head;
alpar@100:       }
alpar@100:       Node n=_queue[_queue_tail++];
alpar@100:       _processed->set(n,true);
alpar@100:       Node m;
alpar@100:       for(OutArcIt e(*G,n);e!=INVALID;++e)
alpar@100: 	if(!(*_reached)[m=G->target(e)]) {
alpar@100: 	  _queue[_queue_head++]=m;
alpar@100: 	  _reached->set(m,true);
alpar@100: 	  _pred->set(m,e);
alpar@100: 	  _dist->set(m,_curr_dist);
alpar@100: 	  if (nm[m] && rnode == INVALID) rnode = m;
alpar@100: 	}
alpar@100:       return n;
alpar@100:     }
alpar@100:       
alpar@100:     ///Next node to be processed.
alpar@100: 
alpar@100:     ///Next node to be processed.
alpar@100:     ///
alpar@100:     ///\return The next node to be processed or INVALID if the queue is
alpar@100:     /// empty.
alpar@100:     Node nextNode()
alpar@100:     { 
alpar@100:       return _queue_tail<_queue_head?_queue[_queue_tail]:INVALID;
alpar@100:     }
alpar@100:  
alpar@100:     ///\brief Returns \c false if there are nodes
alpar@100:     ///to be processed in the queue
alpar@100:     ///
alpar@100:     ///Returns \c false if there are nodes
alpar@100:     ///to be processed in the queue
alpar@100:     bool emptyQueue() { return _queue_tail==_queue_head; }
alpar@100:     ///Returns the number of the nodes to be processed.
alpar@100:     
alpar@100:     ///Returns the number of the nodes to be processed in the queue.
alpar@100:     int queueSize() { return _queue_head-_queue_tail; }
alpar@100:     
alpar@100:     ///Executes the algorithm.
alpar@100: 
alpar@100:     ///Executes the algorithm.
alpar@100:     ///
alpar@100:     ///\pre init() must be called and at least one node should be added
alpar@100:     ///with addSource() before using this function.
alpar@100:     ///
alpar@100:     ///This method runs the %BFS algorithm from the root node(s)
alpar@100:     ///in order to
alpar@100:     ///compute the
alpar@100:     ///shortest path to each node. The algorithm computes
alpar@100:     ///- The shortest path tree.
alpar@100:     ///- The distance of each node from the root(s).
alpar@100:     void start()
alpar@100:     {
alpar@100:       while ( !emptyQueue() ) processNextNode();
alpar@100:     }
alpar@100:     
alpar@100:     ///Executes the algorithm until \c dest is reached.
alpar@100: 
alpar@100:     ///Executes the algorithm until \c dest is reached.
alpar@100:     ///
alpar@100:     ///\pre init() must be called and at least one node should be added
alpar@100:     ///with addSource() before using this function.
alpar@100:     ///
alpar@100:     ///This method runs the %BFS algorithm from the root node(s)
alpar@100:     ///in order to compute the shortest path to \c dest.
alpar@100:     ///The algorithm computes
alpar@100:     ///- The shortest path to \c  dest.
alpar@100:     ///- The distance of \c dest from the root(s).
alpar@100:     void start(Node dest)
alpar@100:     {
alpar@100:       bool reach = false;
alpar@100:       while ( !emptyQueue() && !reach ) processNextNode(dest, reach);
alpar@100:     }
alpar@100:     
alpar@100:     ///Executes the algorithm until a condition is met.
alpar@100: 
alpar@100:     ///Executes the algorithm until a condition is met.
alpar@100:     ///
alpar@100:     ///\pre init() must be called and at least one node should be added
alpar@100:     ///with addSource() before using this function.
alpar@100:     ///
alpar@100:     ///\param nm must be a bool (or convertible) node map. The
alpar@100:     ///algorithm will stop when it reaches a node \c v with
alpar@100:     /// <tt>nm[v]</tt> true.
alpar@100:     ///
alpar@100:     ///\return The reached node \c v with <tt>nm[v]</tt> true or
alpar@100:     ///\c INVALID if no such node was found.
alpar@100:     template<class NM>
alpar@100:     Node start(const NM &nm)
alpar@100:     {
alpar@100:       Node rnode = INVALID;
alpar@100:       while ( !emptyQueue() && rnode == INVALID ) {
alpar@100: 	processNextNode(nm, rnode);
alpar@100:       }
alpar@100:       return rnode;
alpar@100:     }
alpar@100:     
alpar@100:     ///Runs %BFS algorithm from node \c s.
alpar@100:     
alpar@100:     ///This method runs the %BFS algorithm from a root node \c s
alpar@100:     ///in order to
alpar@100:     ///compute the
alpar@100:     ///shortest path to each node. The algorithm computes
alpar@100:     ///- The shortest path tree.
alpar@100:     ///- The distance of each node from the root.
alpar@100:     ///
alpar@100:     ///\note b.run(s) is just a shortcut of the following code.
alpar@100:     ///\code
alpar@100:     ///  b.init();
alpar@100:     ///  b.addSource(s);
alpar@100:     ///  b.start();
alpar@100:     ///\endcode
alpar@100:     void run(Node s) {
alpar@100:       init();
alpar@100:       addSource(s);
alpar@100:       start();
alpar@100:     }
alpar@100:     
alpar@100:     ///Finds the shortest path between \c s and \c t.
alpar@100:     
alpar@100:     ///Finds the shortest path between \c s and \c t.
alpar@100:     ///
alpar@100:     ///\return The length of the shortest s---t path if there exists one,
alpar@100:     ///0 otherwise.
alpar@100:     ///\note Apart from the return value, b.run(s) is
alpar@100:     ///just a shortcut of the following code.
alpar@100:     ///\code
alpar@100:     ///  b.init();
alpar@100:     ///  b.addSource(s);
alpar@100:     ///  b.start(t);
alpar@100:     ///\endcode
alpar@100:     int run(Node s,Node t) {
alpar@100:       init();
alpar@100:       addSource(s);
alpar@100:       start(t);
alpar@100:       return reached(t) ? _curr_dist : 0;
alpar@100:     }
alpar@100:     
alpar@100:     ///@}
alpar@100: 
alpar@100:     ///\name Query Functions
alpar@100:     ///The result of the %BFS algorithm can be obtained using these
alpar@100:     ///functions.\n
alpar@100:     ///Before the use of these functions,
alpar@100:     ///either run() or start() must be calleb.
alpar@100:     
alpar@100:     ///@{
alpar@100: 
alpar@100:     typedef PredMapPath<Digraph, PredMap> Path;
alpar@100: 
alpar@100:     ///Gives back the shortest path.
alpar@100:     
alpar@100:     ///Gives back the shortest path.
alpar@100:     ///\pre The \c t should be reachable from the source.
alpar@100:     Path path(Node t) 
alpar@100:     {
alpar@100:       return Path(*G, *_pred, t);
alpar@100:     }
alpar@100: 
alpar@100:     ///The distance of a node from the root(s).
alpar@100: 
alpar@100:     ///Returns the distance of a node from the root(s).
alpar@100:     ///\pre \ref run() must be called before using this function.
alpar@100:     ///\warning If node \c v in unreachable from the root(s) the return value
alpar@100:     ///of this function is undefined.
alpar@100:     int dist(Node v) const { return (*_dist)[v]; }
alpar@100: 
alpar@100:     ///Returns the 'previous arc' of the shortest path tree.
alpar@100: 
alpar@100:     ///For a node \c v it returns the 'previous arc'
alpar@100:     ///of the shortest path tree,
alpar@100:     ///i.e. it returns the last arc of a shortest path from the root(s) to \c
alpar@100:     ///v. It is \ref INVALID
alpar@100:     ///if \c v is unreachable from the root(s) or \c v is a root. The
alpar@100:     ///shortest path tree used here is equal to the shortest path tree used in
alpar@100:     ///\ref predNode().
alpar@100:     ///\pre Either \ref run() or \ref start() must be called before using
alpar@100:     ///this function.
alpar@100:     Arc predArc(Node v) const { return (*_pred)[v];}
alpar@100: 
alpar@100:     ///Returns the 'previous node' of the shortest path tree.
alpar@100: 
alpar@100:     ///For a node \c v it returns the 'previous node'
alpar@100:     ///of the shortest path tree,
alpar@100:     ///i.e. it returns the last but one node from a shortest path from the
alpar@100:     ///root(a) to \c /v.
alpar@100:     ///It is INVALID if \c v is unreachable from the root(s) or
alpar@100:     ///if \c v itself a root.
alpar@100:     ///The shortest path tree used here is equal to the shortest path
alpar@100:     ///tree used in \ref predArc().
alpar@100:     ///\pre Either \ref run() or \ref start() must be called before
alpar@100:     ///using this function.
alpar@100:     Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
alpar@100: 				  G->source((*_pred)[v]); }
alpar@100:     
alpar@100:     ///Returns a reference to the NodeMap of distances.
alpar@100: 
alpar@100:     ///Returns a reference to the NodeMap of distances.
alpar@100:     ///\pre Either \ref run() or \ref init() must
alpar@100:     ///be called before using this function.
alpar@100:     const DistMap &distMap() const { return *_dist;}
alpar@100:  
alpar@100:     ///Returns a reference to the shortest path tree map.
alpar@100: 
alpar@100:     ///Returns a reference to the NodeMap of the arcs of the
alpar@100:     ///shortest path tree.
alpar@100:     ///\pre Either \ref run() or \ref init()
alpar@100:     ///must be called before using this function.
alpar@100:     const PredMap &predMap() const { return *_pred;}
alpar@100:  
alpar@100:     ///Checks if a node is reachable from the root.
alpar@100: 
alpar@100:     ///Returns \c true if \c v is reachable from the root.
alpar@100:     ///\warning The source nodes are indicated as unreached.
alpar@100:     ///\pre Either \ref run() or \ref start()
alpar@100:     ///must be called before using this function.
alpar@100:     ///
alpar@100:     bool reached(Node v) { return (*_reached)[v]; }
alpar@100:     
alpar@100:     ///@}
alpar@100:   };
alpar@100: 
alpar@100:   ///Default traits class of Bfs function.
alpar@100: 
alpar@100:   ///Default traits class of Bfs function.
kpeter@157:   ///\tparam GR Digraph type.
alpar@100:   template<class GR>
alpar@100:   struct BfsWizardDefaultTraits
alpar@100:   {
alpar@100:     ///The digraph type the algorithm runs on. 
alpar@100:     typedef GR Digraph;
alpar@100:     ///\brief The type of the map that stores the last
alpar@100:     ///arcs of the shortest paths.
alpar@100:     /// 
alpar@100:     ///The type of the map that stores the last
alpar@100:     ///arcs of the shortest paths.
alpar@100:     ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100:     ///
alpar@100:     typedef NullMap<typename Digraph::Node,typename GR::Arc> PredMap;
alpar@100:     ///Instantiates a PredMap.
alpar@100:  
alpar@100:     ///This function instantiates a \ref PredMap. 
alpar@100:     ///\param g is the digraph, to which we would like to define the PredMap.
alpar@100:     ///\todo The digraph alone may be insufficient to initialize
alpar@100: #ifdef DOXYGEN
alpar@100:     static PredMap *createPredMap(const GR &g) 
alpar@100: #else
alpar@100:     static PredMap *createPredMap(const GR &) 
alpar@100: #endif
alpar@100:     {
alpar@100:       return new PredMap();
alpar@100:     }
alpar@100: 
alpar@100:     ///The type of the map that indicates which nodes are processed.
alpar@100:  
alpar@100:     ///The type of the map that indicates which nodes are processed.
alpar@100:     ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100:     ///\todo named parameter to set this type, function to read and write.
alpar@100:     typedef NullMap<typename Digraph::Node,bool> ProcessedMap;
alpar@100:     ///Instantiates a ProcessedMap.
alpar@100:  
alpar@100:     ///This function instantiates a \ref ProcessedMap. 
alpar@100:     ///\param g is the digraph, to which
alpar@100:     ///we would like to define the \ref ProcessedMap
alpar@100: #ifdef DOXYGEN
alpar@100:     static ProcessedMap *createProcessedMap(const GR &g)
alpar@100: #else
alpar@100:     static ProcessedMap *createProcessedMap(const GR &)
alpar@100: #endif
alpar@100:     {
alpar@100:       return new ProcessedMap();
alpar@100:     }
alpar@100:     ///The type of the map that indicates which nodes are reached.
alpar@100:  
alpar@100:     ///The type of the map that indicates which nodes are reached.
alpar@100:     ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100:     ///\todo named parameter to set this type, function to read and write.
alpar@100:     typedef typename Digraph::template NodeMap<bool> ReachedMap;
alpar@100:     ///Instantiates a ReachedMap.
alpar@100:  
alpar@100:     ///This function instantiates a \ref ReachedMap. 
alpar@100:     ///\param G is the digraph, to which
alpar@100:     ///we would like to define the \ref ReachedMap.
alpar@100:     static ReachedMap *createReachedMap(const GR &G)
alpar@100:     {
alpar@100:       return new ReachedMap(G);
alpar@100:     }
alpar@100:     ///The type of the map that stores the dists of the nodes.
alpar@100:  
alpar@100:     ///The type of the map that stores the dists of the nodes.
alpar@100:     ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100:     ///
alpar@100:     typedef NullMap<typename Digraph::Node,int> DistMap;
alpar@100:     ///Instantiates a DistMap.
alpar@100:  
alpar@100:     ///This function instantiates a \ref DistMap. 
alpar@100:     ///\param g is the digraph, to which we would like to define the \ref DistMap
alpar@100: #ifdef DOXYGEN
alpar@100:     static DistMap *createDistMap(const GR &g)
alpar@100: #else
alpar@100:     static DistMap *createDistMap(const GR &)
alpar@100: #endif
alpar@100:     {
alpar@100:       return new DistMap();
alpar@100:     }
alpar@100:   };
alpar@100:   
alpar@100:   /// Default traits used by \ref BfsWizard
alpar@100: 
alpar@100:   /// To make it easier to use Bfs algorithm
alpar@100:   ///we have created a wizard class.
alpar@100:   /// This \ref BfsWizard class needs default traits,
alpar@100:   ///as well as the \ref Bfs class.
alpar@100:   /// The \ref BfsWizardBase is a class to be the default traits of the
alpar@100:   /// \ref BfsWizard class.
alpar@100:   template<class GR>
alpar@100:   class BfsWizardBase : public BfsWizardDefaultTraits<GR>
alpar@100:   {
alpar@100: 
alpar@100:     typedef BfsWizardDefaultTraits<GR> Base;
alpar@100:   protected:
alpar@100:     /// Type of the nodes in the digraph.
alpar@100:     typedef typename Base::Digraph::Node Node;
alpar@100: 
alpar@100:     /// Pointer to the underlying digraph.
alpar@100:     void *_g;
alpar@100:     ///Pointer to the map of reached nodes.
alpar@100:     void *_reached;
alpar@100:     ///Pointer to the map of processed nodes.
alpar@100:     void *_processed;
alpar@100:     ///Pointer to the map of predecessors arcs.
alpar@100:     void *_pred;
alpar@100:     ///Pointer to the map of distances.
alpar@100:     void *_dist;
alpar@100:     ///Pointer to the source node.
alpar@100:     Node _source;
alpar@100:     
alpar@100:     public:
alpar@100:     /// Constructor.
alpar@100:     
alpar@100:     /// This constructor does not require parameters, therefore it initiates
alpar@100:     /// all of the attributes to default values (0, INVALID).
alpar@100:     BfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0),
alpar@100: 			   _dist(0), _source(INVALID) {}
alpar@100: 
alpar@100:     /// Constructor.
alpar@100:     
alpar@100:     /// This constructor requires some parameters,
alpar@100:     /// listed in the parameters list.
alpar@100:     /// Others are initiated to 0.
alpar@100:     /// \param g is the initial value of  \ref _g
alpar@100:     /// \param s is the initial value of  \ref _source
alpar@100:     BfsWizardBase(const GR &g, Node s=INVALID) :
alpar@100:       _g(reinterpret_cast<void*>(const_cast<GR*>(&g))), 
alpar@100:       _reached(0), _processed(0), _pred(0), _dist(0), _source(s) {}
alpar@100: 
alpar@100:   };
alpar@100:   
alpar@100:   /// A class to make the usage of Bfs algorithm easier
alpar@100: 
alpar@100:   /// This class is created to make it easier to use Bfs algorithm.
alpar@100:   /// It uses the functions and features of the plain \ref Bfs,
alpar@100:   /// but it is much simpler to use it.
alpar@100:   ///
alpar@100:   /// Simplicity means that the way to change the types defined
alpar@100:   /// in the traits class is based on functions that returns the new class
alpar@100:   /// and not on templatable built-in classes.
alpar@100:   /// When using the plain \ref Bfs
alpar@100:   /// the new class with the modified type comes from
alpar@100:   /// the original class by using the ::
alpar@100:   /// operator. In the case of \ref BfsWizard only
alpar@100:   /// a function have to be called and it will
alpar@100:   /// return the needed class.
alpar@100:   ///
alpar@100:   /// It does not have own \ref run method. When its \ref run method is called
alpar@100:   /// it initiates a plain \ref Bfs class, and calls the \ref Bfs::run
alpar@100:   /// method of it.
alpar@100:   template<class TR>
alpar@100:   class BfsWizard : public TR
alpar@100:   {
alpar@100:     typedef TR Base;
alpar@100: 
alpar@100:     ///The type of the underlying digraph.
alpar@100:     typedef typename TR::Digraph Digraph;
alpar@100:     //\e
alpar@100:     typedef typename Digraph::Node Node;
alpar@100:     //\e
alpar@100:     typedef typename Digraph::NodeIt NodeIt;
alpar@100:     //\e
alpar@100:     typedef typename Digraph::Arc Arc;
alpar@100:     //\e
alpar@100:     typedef typename Digraph::OutArcIt OutArcIt;
alpar@100:     
alpar@100:     ///\brief The type of the map that stores
alpar@100:     ///the reached nodes
alpar@100:     typedef typename TR::ReachedMap ReachedMap;
alpar@100:     ///\brief The type of the map that stores
alpar@100:     ///the processed nodes
alpar@100:     typedef typename TR::ProcessedMap ProcessedMap;
alpar@100:     ///\brief The type of the map that stores the last
alpar@100:     ///arcs of the shortest paths.
alpar@100:     typedef typename TR::PredMap PredMap;
alpar@100:     ///The type of the map that stores the dists of the nodes.
alpar@100:     typedef typename TR::DistMap DistMap;
alpar@100: 
alpar@100:   public:
alpar@100:     /// Constructor.
alpar@100:     BfsWizard() : TR() {}
alpar@100: 
alpar@100:     /// Constructor that requires parameters.
alpar@100: 
alpar@100:     /// Constructor that requires parameters.
alpar@100:     /// These parameters will be the default values for the traits class.
alpar@100:     BfsWizard(const Digraph &g, Node s=INVALID) :
alpar@100:       TR(g,s) {}
alpar@100: 
alpar@100:     ///Copy constructor
alpar@100:     BfsWizard(const TR &b) : TR(b) {}
alpar@100: 
alpar@100:     ~BfsWizard() {}
alpar@100: 
alpar@100:     ///Runs Bfs algorithm from a given node.
alpar@100:     
alpar@100:     ///Runs Bfs algorithm from a given node.
alpar@100:     ///The node can be given by the \ref source function.
alpar@100:     void run()
alpar@100:     {
alpar@100:       if(Base::_source==INVALID) throw UninitializedParameter();
alpar@100:       Bfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g));
alpar@100:       if(Base::_reached)
alpar@100: 	alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached));
alpar@100:       if(Base::_processed) 
alpar@100:         alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed));
alpar@100:       if(Base::_pred) 
alpar@100:         alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred));
alpar@100:       if(Base::_dist) 
alpar@100:         alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist));
alpar@100:       alg.run(Base::_source);
alpar@100:     }
alpar@100: 
alpar@100:     ///Runs Bfs algorithm from the given node.
alpar@100: 
alpar@100:     ///Runs Bfs algorithm from the given node.
alpar@100:     ///\param s is the given source.
alpar@100:     void run(Node s)
alpar@100:     {
alpar@100:       Base::_source=s;
alpar@100:       run();
alpar@100:     }
alpar@100: 
alpar@100:     template<class T>
alpar@100:     struct DefPredMapBase : public Base {
alpar@100:       typedef T PredMap;
alpar@100:       static PredMap *createPredMap(const Digraph &) { return 0; };
alpar@100:       DefPredMapBase(const TR &b) : TR(b) {}
alpar@100:     };
alpar@100:     
alpar@100:     ///\brief \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting PredMap
alpar@100:     ///
alpar@100:     /// \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting PredMap
alpar@100:     ///
alpar@100:     template<class T>
alpar@100:     BfsWizard<DefPredMapBase<T> > predMap(const T &t) 
alpar@100:     {
alpar@100:       Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100:       return BfsWizard<DefPredMapBase<T> >(*this);
alpar@100:     }
alpar@100:     
alpar@100:  
alpar@100:     template<class T>
alpar@100:     struct DefReachedMapBase : public Base {
alpar@100:       typedef T ReachedMap;
alpar@100:       static ReachedMap *createReachedMap(const Digraph &) { return 0; };
alpar@100:       DefReachedMapBase(const TR &b) : TR(b) {}
alpar@100:     };
alpar@100:     
alpar@100:     ///\brief \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting ReachedMap
alpar@100:     ///
alpar@100:     /// \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting ReachedMap
alpar@100:     ///
alpar@100:     template<class T>
alpar@100:     BfsWizard<DefReachedMapBase<T> > reachedMap(const T &t) 
alpar@100:     {
deba@158:       Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100:       return BfsWizard<DefReachedMapBase<T> >(*this);
alpar@100:     }
alpar@100:     
alpar@100: 
alpar@100:     template<class T>
alpar@100:     struct DefProcessedMapBase : public Base {
alpar@100:       typedef T ProcessedMap;
alpar@100:       static ProcessedMap *createProcessedMap(const Digraph &) { return 0; };
alpar@100:       DefProcessedMapBase(const TR &b) : TR(b) {}
alpar@100:     };
alpar@100:     
alpar@100:     ///\brief \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting ProcessedMap
alpar@100:     ///
alpar@100:     /// \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting ProcessedMap
alpar@100:     ///
alpar@100:     template<class T>
alpar@100:     BfsWizard<DefProcessedMapBase<T> > processedMap(const T &t) 
alpar@100:     {
deba@158:       Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100:       return BfsWizard<DefProcessedMapBase<T> >(*this);
alpar@100:     }
alpar@100:     
alpar@100:    
alpar@100:     template<class T>
alpar@100:     struct DefDistMapBase : public Base {
alpar@100:       typedef T DistMap;
alpar@100:       static DistMap *createDistMap(const Digraph &) { return 0; };
alpar@100:       DefDistMapBase(const TR &b) : TR(b) {}
alpar@100:     };
alpar@100:     
alpar@100:     ///\brief \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting DistMap type
alpar@100:     ///
alpar@100:     /// \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting DistMap type
alpar@100:     ///
alpar@100:     template<class T>
alpar@100:     BfsWizard<DefDistMapBase<T> > distMap(const T &t) 
alpar@100:     {
alpar@100:       Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100:       return BfsWizard<DefDistMapBase<T> >(*this);
alpar@100:     }
alpar@100:     
alpar@100:     /// Sets the source node, from which the Bfs algorithm runs.
alpar@100: 
alpar@100:     /// Sets the source node, from which the Bfs algorithm runs.
alpar@100:     /// \param s is the source node.
alpar@100:     BfsWizard<TR> &source(Node s) 
alpar@100:     {
alpar@100:       Base::_source=s;
alpar@100:       return *this;
alpar@100:     }
alpar@100:     
alpar@100:   };
alpar@100:   
alpar@100:   ///Function type interface for Bfs algorithm.
alpar@100: 
alpar@100:   /// \ingroup search
alpar@100:   ///Function type interface for Bfs algorithm.
alpar@100:   ///
alpar@100:   ///This function also has several
alpar@100:   ///\ref named-templ-func-param "named parameters",
alpar@100:   ///they are declared as the members of class \ref BfsWizard.
alpar@100:   ///The following
alpar@100:   ///example shows how to use these parameters.
alpar@100:   ///\code
alpar@100:   ///  bfs(g,source).predMap(preds).run();
alpar@100:   ///\endcode
alpar@100:   ///\warning Don't forget to put the \ref BfsWizard::run() "run()"
alpar@100:   ///to the end of the parameter list.
alpar@100:   ///\sa BfsWizard
alpar@100:   ///\sa Bfs
alpar@100:   template<class GR>
alpar@100:   BfsWizard<BfsWizardBase<GR> >
alpar@100:   bfs(const GR &g,typename GR::Node s=INVALID)
alpar@100:   {
alpar@100:     return BfsWizard<BfsWizardBase<GR> >(g,s);
alpar@100:   }
alpar@100: 
alpar@100: #ifdef DOXYGEN
alpar@100:   /// \brief Visitor class for bfs.
alpar@100:   ///  
alpar@100:   /// This class defines the interface of the BfsVisit events, and
alpar@100:   /// it could be the base of a real Visitor class.
alpar@100:   template <typename _Digraph>
alpar@100:   struct BfsVisitor {
alpar@100:     typedef _Digraph Digraph;
alpar@100:     typedef typename Digraph::Arc Arc;
alpar@100:     typedef typename Digraph::Node Node;
alpar@100:     /// \brief Called when the arc reach a node.
alpar@100:     /// 
alpar@100:     /// It is called when the bfs find an arc which target is not
alpar@100:     /// reached yet.
alpar@100:     void discover(const Arc& arc) {}
alpar@100:     /// \brief Called when the node reached first time.
alpar@100:     /// 
alpar@100:     /// It is Called when the node reached first time.
alpar@100:     void reach(const Node& node) {}
alpar@100:     /// \brief Called when the arc examined but target of the arc 
alpar@100:     /// already discovered.
alpar@100:     /// 
alpar@100:     /// It called when the arc examined but the target of the arc 
alpar@100:     /// already discovered.
alpar@100:     void examine(const Arc& arc) {}
alpar@100:     /// \brief Called for the source node of the bfs.
alpar@100:     /// 
alpar@100:     /// It is called for the source node of the bfs.
alpar@100:     void start(const Node& node) {}
alpar@100:     /// \brief Called when the node processed.
alpar@100:     /// 
alpar@100:     /// It is Called when the node processed.
alpar@100:     void process(const Node& node) {}
alpar@100:   };
alpar@100: #else
alpar@100:   template <typename _Digraph>
alpar@100:   struct BfsVisitor {
alpar@100:     typedef _Digraph Digraph;
alpar@100:     typedef typename Digraph::Arc Arc;
alpar@100:     typedef typename Digraph::Node Node;
alpar@100:     void discover(const Arc&) {}
alpar@100:     void reach(const Node&) {}
alpar@100:     void examine(const Arc&) {}
alpar@100:     void start(const Node&) {}
alpar@100:     void process(const Node&) {}
alpar@100: 
alpar@100:     template <typename _Visitor>
alpar@100:     struct Constraints {
alpar@100:       void constraints() {
alpar@100: 	Arc arc;
alpar@100: 	Node node;
alpar@100: 	visitor.discover(arc);
alpar@100: 	visitor.reach(node);
alpar@100: 	visitor.examine(arc);
alpar@100: 	visitor.start(node);
alpar@100:         visitor.process(node);
alpar@100:       }
alpar@100:       _Visitor& visitor;
alpar@100:     };
alpar@100:   };
alpar@100: #endif
alpar@100: 
alpar@100:   /// \brief Default traits class of BfsVisit class.
alpar@100:   ///
alpar@100:   /// Default traits class of BfsVisit class.
kpeter@157:   /// \tparam _Digraph Digraph type.
alpar@100:   template<class _Digraph>
alpar@100:   struct BfsVisitDefaultTraits {
alpar@100: 
alpar@100:     /// \brief The digraph type the algorithm runs on. 
alpar@100:     typedef _Digraph Digraph;
alpar@100: 
alpar@100:     /// \brief The type of the map that indicates which nodes are reached.
alpar@100:     /// 
alpar@100:     /// The type of the map that indicates which nodes are reached.
alpar@100:     /// It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100:     /// \todo named parameter to set this type, function to read and write.
alpar@100:     typedef typename Digraph::template NodeMap<bool> ReachedMap;
alpar@100: 
alpar@100:     /// \brief Instantiates a ReachedMap.
alpar@100:     ///
alpar@100:     /// This function instantiates a \ref ReachedMap. 
alpar@100:     /// \param digraph is the digraph, to which
alpar@100:     /// we would like to define the \ref ReachedMap.
alpar@100:     static ReachedMap *createReachedMap(const Digraph &digraph) {
alpar@100:       return new ReachedMap(digraph);
alpar@100:     }
alpar@100: 
alpar@100:   };
alpar@100: 
alpar@100:   /// \ingroup search
alpar@100:   ///  
alpar@100:   /// \brief %BFS Visit algorithm class.
alpar@100:   ///  
alpar@100:   /// This class provides an efficient implementation of the %BFS algorithm
alpar@100:   /// with visitor interface.
alpar@100:   ///
alpar@100:   /// The %BfsVisit class provides an alternative interface to the Bfs
alpar@100:   /// class. It works with callback mechanism, the BfsVisit object calls
alpar@100:   /// on every bfs event the \c Visitor class member functions. 
alpar@100:   ///
kpeter@157:   /// \tparam _Digraph The digraph type the algorithm runs on. The default value is
alpar@100:   /// \ref ListDigraph. The value of _Digraph is not used directly by Bfs, it
alpar@100:   /// is only passed to \ref BfsDefaultTraits.
kpeter@157:   /// \tparam _Visitor The Visitor object for the algorithm. The 
alpar@100:   /// \ref BfsVisitor "BfsVisitor<_Digraph>" is an empty Visitor which
alpar@100:   /// does not observe the Bfs events. If you want to observe the bfs
alpar@100:   /// events you should implement your own Visitor class.
kpeter@157:   /// \tparam _Traits Traits class to set various data types used by the 
alpar@100:   /// algorithm. The default traits class is
alpar@100:   /// \ref BfsVisitDefaultTraits "BfsVisitDefaultTraits<_Digraph>".
alpar@100:   /// See \ref BfsVisitDefaultTraits for the documentation of
alpar@100:   /// a Bfs visit traits class.
alpar@100: #ifdef DOXYGEN
alpar@100:   template <typename _Digraph, typename _Visitor, typename _Traits>
alpar@100: #else
alpar@100:   template <typename _Digraph = ListDigraph,
alpar@100: 	    typename _Visitor = BfsVisitor<_Digraph>,
alpar@100: 	    typename _Traits = BfsDefaultTraits<_Digraph> >
alpar@100: #endif
alpar@100:   class BfsVisit {
alpar@100:   public:
alpar@100:     
alpar@100:     /// \brief \ref Exception for uninitialized parameters.
alpar@100:     ///
alpar@100:     /// This error represents problems in the initialization
alpar@100:     /// of the parameters of the algorithms.
alpar@100:     class UninitializedParameter : public lemon::UninitializedParameter {
alpar@100:     public:
alpar@100:       virtual const char* what() const throw() 
alpar@100:       {
alpar@100: 	return "lemon::BfsVisit::UninitializedParameter";
alpar@100:       }
alpar@100:     };
alpar@100: 
alpar@100:     typedef _Traits Traits;
alpar@100: 
alpar@100:     typedef typename Traits::Digraph Digraph;
alpar@100: 
alpar@100:     typedef _Visitor Visitor;
alpar@100: 
alpar@100:     ///The type of the map indicating which nodes are reached.
alpar@100:     typedef typename Traits::ReachedMap ReachedMap;
alpar@100: 
alpar@100:   private:
alpar@100: 
alpar@100:     typedef typename Digraph::Node Node;
alpar@100:     typedef typename Digraph::NodeIt NodeIt;
alpar@100:     typedef typename Digraph::Arc Arc;
alpar@100:     typedef typename Digraph::OutArcIt OutArcIt;
alpar@100: 
alpar@100:     /// Pointer to the underlying digraph.
alpar@100:     const Digraph *_digraph;
alpar@100:     /// Pointer to the visitor object.
alpar@100:     Visitor *_visitor;
alpar@100:     ///Pointer to the map of reached status of the nodes.
alpar@100:     ReachedMap *_reached;
alpar@100:     ///Indicates if \ref _reached is locally allocated (\c true) or not.
alpar@100:     bool local_reached;
alpar@100: 
alpar@100:     std::vector<typename Digraph::Node> _list;
alpar@100:     int _list_front, _list_back;
alpar@100: 
alpar@100:     /// \brief Creates the maps if necessary.
alpar@100:     ///
alpar@100:     /// Creates the maps if necessary.
alpar@100:     void create_maps() {
alpar@100:       if(!_reached) {
alpar@100: 	local_reached = true;
alpar@100: 	_reached = Traits::createReachedMap(*_digraph);
alpar@100:       }
alpar@100:     }
alpar@100: 
alpar@100:   protected:
alpar@100: 
alpar@100:     BfsVisit() {}
alpar@100:     
alpar@100:   public:
alpar@100: 
alpar@100:     typedef BfsVisit Create;
alpar@100: 
alpar@100:     /// \name Named template parameters
alpar@100: 
alpar@100:     ///@{
alpar@100:     template <class T>
alpar@100:     struct DefReachedMapTraits : public Traits {
alpar@100:       typedef T ReachedMap;
alpar@100:       static ReachedMap *createReachedMap(const Digraph &digraph) {
alpar@100: 	throw UninitializedParameter();
alpar@100:       }
alpar@100:     };
alpar@100:     /// \brief \ref named-templ-param "Named parameter" for setting 
alpar@100:     /// ReachedMap type
alpar@100:     ///
alpar@100:     /// \ref named-templ-param "Named parameter" for setting ReachedMap type
alpar@100:     template <class T>
alpar@100:     struct DefReachedMap : public BfsVisit< Digraph, Visitor,
alpar@100: 					    DefReachedMapTraits<T> > {
alpar@100:       typedef BfsVisit< Digraph, Visitor, DefReachedMapTraits<T> > Create;
alpar@100:     };
alpar@100:     ///@}
alpar@100: 
alpar@100:   public:      
alpar@100:     
alpar@100:     /// \brief Constructor.
alpar@100:     ///
alpar@100:     /// Constructor.
alpar@100:     ///
alpar@100:     /// \param digraph the digraph the algorithm will run on.
alpar@100:     /// \param visitor The visitor of the algorithm.
alpar@100:     ///
alpar@100:     BfsVisit(const Digraph& digraph, Visitor& visitor) 
alpar@100:       : _digraph(&digraph), _visitor(&visitor),
alpar@100: 	_reached(0), local_reached(false) {}
alpar@100:     
alpar@100:     /// \brief Destructor.
alpar@100:     ///
alpar@100:     /// Destructor.
alpar@100:     ~BfsVisit() {
alpar@100:       if(local_reached) delete _reached;
alpar@100:     }
alpar@100: 
alpar@100:     /// \brief Sets the map indicating if a node is reached.
alpar@100:     ///
alpar@100:     /// Sets the map indicating if a node is reached.
alpar@100:     /// If you don't use this function before calling \ref run(),
alpar@100:     /// it will allocate one. The destuctor deallocates this
alpar@100:     /// automatically allocated map, of course.
alpar@100:     /// \return <tt> (*this) </tt>
alpar@100:     BfsVisit &reachedMap(ReachedMap &m) {
alpar@100:       if(local_reached) {
alpar@100: 	delete _reached;
alpar@100: 	local_reached = false;
alpar@100:       }
alpar@100:       _reached = &m;
alpar@100:       return *this;
alpar@100:     }
alpar@100: 
alpar@100:   public:
alpar@100:     /// \name Execution control
alpar@100:     /// The simplest way to execute the algorithm is to use
alpar@100:     /// one of the member functions called \c run(...).
alpar@100:     /// \n
alpar@100:     /// If you need more control on the execution,
alpar@100:     /// first you must call \ref init(), then you can adda source node
alpar@100:     /// with \ref addSource().
alpar@100:     /// Finally \ref start() will perform the actual path
alpar@100:     /// computation.
alpar@100: 
alpar@100:     /// @{
alpar@100:     /// \brief Initializes the internal data structures.
alpar@100:     ///
alpar@100:     /// Initializes the internal data structures.
alpar@100:     ///
alpar@100:     void init() {
alpar@100:       create_maps();
alpar@100:       _list.resize(countNodes(*_digraph));
alpar@100:       _list_front = _list_back = -1;
alpar@100:       for (NodeIt u(*_digraph) ; u != INVALID ; ++u) {
alpar@100: 	_reached->set(u, false);
alpar@100:       }
alpar@100:     }
alpar@100:     
alpar@100:     /// \brief Adds a new source node.
alpar@100:     ///
alpar@100:     /// Adds a new source node to the set of nodes to be processed.
alpar@100:     void addSource(Node s) {
alpar@100:       if(!(*_reached)[s]) {
alpar@100: 	  _reached->set(s,true);
alpar@100: 	  _visitor->start(s);
alpar@100: 	  _visitor->reach(s);
alpar@100:           _list[++_list_back] = s;
alpar@100: 	}
alpar@100:     }
alpar@100:     
alpar@100:     /// \brief Processes the next node.
alpar@100:     ///
alpar@100:     /// Processes the next node.
alpar@100:     ///
alpar@100:     /// \return The processed node.
alpar@100:     ///
alpar@100:     /// \pre The queue must not be empty!
alpar@100:     Node processNextNode() { 
alpar@100:       Node n = _list[++_list_front];
alpar@100:       _visitor->process(n);
alpar@100:       Arc e;
alpar@100:       for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) {
alpar@100:         Node m = _digraph->target(e);
alpar@100:         if (!(*_reached)[m]) {
alpar@100:           _visitor->discover(e);
alpar@100:           _visitor->reach(m);
alpar@100:           _reached->set(m, true);
alpar@100:           _list[++_list_back] = m;
alpar@100:         } else {
alpar@100:           _visitor->examine(e);
alpar@100:         }
alpar@100:       }
alpar@100:       return n;
alpar@100:     }
alpar@100: 
alpar@100:     /// \brief Processes the next node.
alpar@100:     ///
alpar@100:     /// Processes the next node. And checks that the given target node
alpar@100:     /// is reached. If the target node is reachable from the processed
alpar@100:     /// node then the reached parameter will be set true. The reached
alpar@100:     /// parameter should be initially false.
alpar@100:     ///
alpar@100:     /// \param target The target node.
alpar@100:     /// \retval reach Indicates that the target node is reached.
alpar@100:     /// \return The processed node.
alpar@100:     ///
alpar@100:     /// \warning The queue must not be empty!
alpar@100:     Node processNextNode(Node target, bool& reach) {
alpar@100:       Node n = _list[++_list_front];
alpar@100:       _visitor->process(n);
alpar@100:       Arc e;
alpar@100:       for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) {
alpar@100:         Node m = _digraph->target(e);
alpar@100:         if (!(*_reached)[m]) {
alpar@100:           _visitor->discover(e);
alpar@100:           _visitor->reach(m);
alpar@100:           _reached->set(m, true);
alpar@100:           _list[++_list_back] = m;
alpar@100:           reach = reach || (target == m);
alpar@100:         } else {
alpar@100:           _visitor->examine(e);
alpar@100:         }
alpar@100:       }
alpar@100:       return n;
alpar@100:     }
alpar@100: 
alpar@100:     /// \brief Processes the next node.
alpar@100:     ///
alpar@100:     /// Processes the next node. And checks that at least one of
alpar@100:     /// reached node has true value in the \c nm node map. If one node
alpar@100:     /// with true value is reachable from the processed node then the
alpar@100:     /// rnode parameter will be set to the first of such nodes.
alpar@100:     ///
alpar@100:     /// \param nm The node map of possible targets.
alpar@100:     /// \retval rnode The reached target node.
alpar@100:     /// \return The processed node.
alpar@100:     ///
alpar@100:     /// \warning The queue must not be empty!
alpar@100:     template <typename NM>
alpar@100:     Node processNextNode(const NM& nm, Node& rnode) {
alpar@100:       Node n = _list[++_list_front];
alpar@100:       _visitor->process(n);
alpar@100:       Arc e;
alpar@100:       for (_digraph->firstOut(e, n); e != INVALID; _digraph->nextOut(e)) {
alpar@100:         Node m = _digraph->target(e);
alpar@100:         if (!(*_reached)[m]) {
alpar@100:           _visitor->discover(e);
alpar@100:           _visitor->reach(m);
alpar@100:           _reached->set(m, true);
alpar@100:           _list[++_list_back] = m;
alpar@100:           if (nm[m] && rnode == INVALID) rnode = m;
alpar@100:         } else {
alpar@100:           _visitor->examine(e);
alpar@100:         }
alpar@100:       }
alpar@100:       return n;
alpar@100:     }
alpar@100: 
alpar@100:     /// \brief Next node to be processed.
alpar@100:     ///
alpar@100:     /// Next node to be processed.
alpar@100:     ///
alpar@100:     /// \return The next node to be processed or INVALID if the stack is
alpar@100:     /// empty.
alpar@100:     Node nextNode() { 
alpar@100:       return _list_front != _list_back ? _list[_list_front + 1] : INVALID;
alpar@100:     }
alpar@100: 
alpar@100:     /// \brief Returns \c false if there are nodes
alpar@100:     /// to be processed in the queue
alpar@100:     ///
alpar@100:     /// Returns \c false if there are nodes
alpar@100:     /// to be processed in the queue
alpar@100:     bool emptyQueue() { return _list_front == _list_back; }
alpar@100: 
alpar@100:     /// \brief Returns the number of the nodes to be processed.
alpar@100:     ///
alpar@100:     /// Returns the number of the nodes to be processed in the queue.
alpar@100:     int queueSize() { return _list_back - _list_front; }
alpar@100:     
alpar@100:     /// \brief Executes the algorithm.
alpar@100:     ///
alpar@100:     /// Executes the algorithm.
alpar@100:     ///
alpar@100:     /// \pre init() must be called and at least one node should be added
alpar@100:     /// with addSource() before using this function.
alpar@100:     void start() {
alpar@100:       while ( !emptyQueue() ) processNextNode();
alpar@100:     }
alpar@100:     
alpar@100:     /// \brief Executes the algorithm until \c dest is reached.
alpar@100:     ///
alpar@100:     /// Executes the algorithm until \c dest is reached.
alpar@100:     ///
alpar@100:     /// \pre init() must be called and at least one node should be added
alpar@100:     /// with addSource() before using this function.
alpar@100:     void start(Node dest) {
alpar@100:       bool reach = false;
alpar@100:       while ( !emptyQueue() && !reach ) processNextNode(dest, reach);
alpar@100:     }
alpar@100:     
alpar@100:     /// \brief Executes the algorithm until a condition is met.
alpar@100:     ///
alpar@100:     /// Executes the algorithm until a condition is met.
alpar@100:     ///
alpar@100:     /// \pre init() must be called and at least one node should be added
alpar@100:     /// with addSource() before using this function.
alpar@100:     ///
alpar@100:     ///\param nm must be a bool (or convertible) node map. The
alpar@100:     ///algorithm will stop when it reaches a node \c v with
alpar@100:     /// <tt>nm[v]</tt> true.
alpar@100:     ///
alpar@100:     ///\return The reached node \c v with <tt>nm[v]</tt> true or
alpar@100:     ///\c INVALID if no such node was found.
alpar@100:     template <typename NM>
alpar@100:     Node start(const NM &nm) {
alpar@100:       Node rnode = INVALID;
alpar@100:       while ( !emptyQueue() && rnode == INVALID ) {
alpar@100: 	processNextNode(nm, rnode);
alpar@100:       }
alpar@100:       return rnode;
alpar@100:     }
alpar@100: 
alpar@100:     /// \brief Runs %BFSVisit algorithm from node \c s.
alpar@100:     ///
alpar@100:     /// This method runs the %BFS algorithm from a root node \c s.
alpar@100:     /// \note b.run(s) is just a shortcut of the following code.
alpar@100:     ///\code
alpar@100:     ///   b.init();
alpar@100:     ///   b.addSource(s);
alpar@100:     ///   b.start();
alpar@100:     ///\endcode
alpar@100:     void run(Node s) {
alpar@100:       init();
alpar@100:       addSource(s);
alpar@100:       start();
alpar@100:     }
alpar@100: 
alpar@100:     /// \brief Runs %BFSVisit algorithm to visit all nodes in the digraph.
alpar@100:     ///    
alpar@100:     /// This method runs the %BFS algorithm in order to
alpar@100:     /// compute the %BFS path to each node. The algorithm computes
alpar@100:     /// - The %BFS tree.
alpar@100:     /// - The distance of each node from the root in the %BFS tree.
alpar@100:     ///
alpar@100:     ///\note b.run() is just a shortcut of the following code.
alpar@100:     ///\code
alpar@100:     ///  b.init();
alpar@100:     ///  for (NodeIt it(digraph); it != INVALID; ++it) {
alpar@100:     ///    if (!b.reached(it)) {
alpar@100:     ///      b.addSource(it);
alpar@100:     ///      b.start();
alpar@100:     ///    }
alpar@100:     ///  }
alpar@100:     ///\endcode
alpar@100:     void run() {
alpar@100:       init();
alpar@100:       for (NodeIt it(*_digraph); it != INVALID; ++it) {
alpar@100:         if (!reached(it)) {
alpar@100:           addSource(it);
alpar@100:           start();
alpar@100:         }
alpar@100:       }
alpar@100:     }
alpar@100:     ///@}
alpar@100: 
alpar@100:     /// \name Query Functions
alpar@100:     /// The result of the %BFS algorithm can be obtained using these
alpar@100:     /// functions.\n
alpar@100:     /// Before the use of these functions,
alpar@100:     /// either run() or start() must be called.
alpar@100:     ///@{
alpar@100: 
alpar@100:     /// \brief Checks if a node is reachable from the root.
alpar@100:     ///
alpar@100:     /// Returns \c true if \c v is reachable from the root(s).
alpar@100:     /// \warning The source nodes are inditated as unreachable.
alpar@100:     /// \pre Either \ref run() or \ref start()
alpar@100:     /// must be called before using this function.
alpar@100:     ///
alpar@100:     bool reached(Node v) { return (*_reached)[v]; }
alpar@100:     ///@}
alpar@100:   };
alpar@100: 
alpar@100: } //END OF NAMESPACE LEMON
alpar@100: 
alpar@100: #endif
alpar@100: