alpar@209: /* -*- mode: C++; indent-tabs-mode: nil; -*-
alpar@100:  *
alpar@209:  * 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_DFS_H
alpar@100: #define LEMON_DFS_H
alpar@100: 
alpar@100: ///\ingroup search
alpar@100: ///\file
alpar@100: ///\brief Dfs algorithm.
alpar@100: 
alpar@100: #include <lemon/list_graph.h>
alpar@100: #include <lemon/bits/path_dump.h>
deba@220: #include <lemon/core.h>
alpar@100: #include <lemon/error.h>
alpar@100: #include <lemon/maps.h>
alpar@100: 
alpar@100: #include <lemon/concept_check.h>
alpar@100: 
alpar@100: namespace lemon {
alpar@100: 
alpar@209: 
alpar@100:   ///Default traits class of Dfs class.
alpar@100: 
alpar@100:   ///Default traits class of Dfs class.
kpeter@157:   ///\tparam GR Digraph type.
alpar@100:   template<class GR>
alpar@100:   struct DfsDefaultTraits
alpar@100:   {
alpar@209:     ///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 %DFS paths.
alpar@209:     ///
alpar@100:     ///The type of the map that stores the last
alpar@100:     ///arcs of the %DFS 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@209: 
alpar@209:     ///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@209:     static PredMap *createPredMap(const GR &G)
alpar@100:     {
alpar@100:       return new PredMap(G);
alpar@100:     }
alpar@100: 
alpar@100:     ///The type of the map that indicates which nodes are processed.
alpar@209: 
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@209: 
alpar@209:     ///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@209: 
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@209: 
alpar@209:     ///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@209: 
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@209: 
alpar@209:     ///This function instantiates a \ref DistMap.
alpar@210:     ///\param G is the digraph, to which we would like to define
alpar@210:     ///the \ref DistMap
alpar@100:     static DistMap *createDistMap(const GR &G)
alpar@100:     {
alpar@100:       return new DistMap(G);
alpar@100:     }
alpar@100:   };
alpar@209: 
alpar@100:   ///%DFS algorithm class.
alpar@209: 
alpar@100:   ///\ingroup search
alpar@100:   ///This class provides an efficient implementation of the %DFS 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 Dfs, it
alpar@100:   ///is only passed to \ref DfsDefaultTraits.
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 DfsDefaultTraits "DfsDefaultTraits<GR>".
alpar@100:   ///See \ref DfsDefaultTraits for the documentation of
alpar@100:   ///a Dfs traits class.
alpar@100: #ifdef DOXYGEN
alpar@100:   template <typename GR,
alpar@209:             typename TR>
alpar@100: #else
alpar@100:   template <typename GR=ListDigraph,
alpar@209:             typename TR=DfsDefaultTraits<GR> >
alpar@100: #endif
alpar@100:   class Dfs {
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@209:         return "lemon::Dfs::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:     ///\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@209: 
alpar@100:     ///\brief The type of the map that stores the last
alpar@100:     ///arcs of the %DFS 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:     /// 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::OutArcIt> _stack;
alpar@100:     int _stack_head;
alpar@100: 
alpar@100:     ///Creates the maps if necessary.
alpar@209: 
alpar@100:     ///\todo Better memory allocation (instead of new).
alpar@209:     void create_maps()
alpar@100:     {
alpar@100:       if(!_pred) {
alpar@209:         local_pred = true;
alpar@209:         _pred = Traits::createPredMap(*G);
alpar@100:       }
alpar@100:       if(!_dist) {
alpar@209:         local_dist = true;
alpar@209:         _dist = Traits::createDistMap(*G);
alpar@100:       }
alpar@100:       if(!_reached) {
alpar@209:         local_reached = true;
alpar@209:         _reached = Traits::createReachedMap(*G);
alpar@100:       }
alpar@100:       if(!_processed) {
alpar@209:         local_processed = true;
alpar@209:         _processed = Traits::createProcessedMap(*G);
alpar@100:       }
alpar@100:     }
alpar@100: 
alpar@100:   protected:
alpar@100: 
alpar@100:     Dfs() {}
alpar@209: 
alpar@100:   public:
alpar@100: 
alpar@100:     typedef Dfs 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@209:       static PredMap *createPredMap(const Digraph &G)
alpar@100:       {
alpar@209:         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 Dfs<Digraph, DefPredMapTraits<T> > {
alpar@100:       typedef Dfs<Digraph, DefPredMapTraits<T> > Create;
alpar@100:     };
alpar@209: 
alpar@209: 
alpar@100:     template <class T>
alpar@100:     struct DefDistMapTraits : public Traits {
alpar@100:       typedef T DistMap;
alpar@209:       static DistMap *createDistMap(const Digraph &)
alpar@100:       {
alpar@209:         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
alpar@100:     ///type
alpar@100:     template <class T>
alpar@100:     struct DefDistMap {
alpar@100:       typedef Dfs<Digraph, DefDistMapTraits<T> > Create;
alpar@100:     };
alpar@209: 
alpar@100:     template <class T>
alpar@100:     struct DefReachedMapTraits : public Traits {
alpar@100:       typedef T ReachedMap;
alpar@209:       static ReachedMap *createReachedMap(const Digraph &)
alpar@100:       {
alpar@209:         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 Dfs< Digraph, DefReachedMapTraits<T> > {
alpar@100:       typedef Dfs< 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@209:       static ProcessedMap *createProcessedMap(const Digraph &)
alpar@100:       {
alpar@209:         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@209:     struct DefProcessedMap : public Dfs< Digraph, DefProcessedMapTraits<T> > {
alpar@100:       typedef Dfs< Digraph, DefProcessedMapTraits<T> > Create;
alpar@100:     };
alpar@209: 
alpar@100:     struct DefDigraphProcessedMapTraits : public Traits {
alpar@100:       typedef typename Digraph::template NodeMap<bool> ProcessedMap;
alpar@209:       static ProcessedMap *createProcessedMap(const Digraph &G)
alpar@100:       {
alpar@209:         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 explicitely, it will be automatically allocated.
alpar@100:     template <class T>
alpar@100:     class DefProcessedMapToBeDefaultMap :
alpar@209:       public Dfs< Digraph, DefDigraphProcessedMapTraits> {
alpar@100:       typedef Dfs< Digraph, DefDigraphProcessedMapTraits> Create;
alpar@100:     };
alpar@209: 
alpar@100:     ///@}
alpar@100: 
alpar@209:   public:
alpar@209: 
alpar@100:     ///Constructor.
alpar@209: 
alpar@100:     ///\param _G the digraph the algorithm will run on.
alpar@100:     ///
alpar@100:     Dfs(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@209: 
alpar@100:     ///Destructor.
alpar@209:     ~Dfs()
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 destuctor deallocates this
alpar@100:     ///automatically allocated map, of course.
alpar@100:     ///\return <tt> (*this) </tt>
alpar@209:     Dfs &predMap(PredMap &m)
alpar@100:     {
alpar@100:       if(local_pred) {
alpar@209:         delete _pred;
alpar@209:         local_pred=false;
alpar@100:       }
alpar@100:       _pred = &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 destuctor deallocates this
alpar@100:     ///automatically allocated map, of course.
alpar@100:     ///\return <tt> (*this) </tt>
alpar@209:     Dfs &distMap(DistMap &m)
alpar@100:     {
alpar@100:       if(local_dist) {
alpar@209:         delete _dist;
alpar@209:         local_dist=false;
alpar@100:       }
alpar@100:       _dist = &m;
alpar@100:       return *this;
alpar@100:     }
alpar@100: 
alpar@100:     ///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@209:     Dfs &reachedMap(ReachedMap &m)
alpar@100:     {
alpar@100:       if(local_reached) {
alpar@209:         delete _reached;
alpar@209:         local_reached=false;
alpar@100:       }
alpar@100:       _reached = &m;
alpar@100:       return *this;
alpar@100:     }
alpar@100: 
alpar@100:     ///Sets the map indicating if a node is processed.
alpar@100: 
alpar@100:     ///Sets the map indicating if a node is processed.
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@209:     Dfs &processedMap(ProcessedMap &m)
alpar@100:     {
alpar@100:       if(local_processed) {
alpar@209:         delete _processed;
alpar@209:         local_processed=false;
alpar@100:       }
alpar@100:       _processed = &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 a 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: 
alpar@100:     ///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:       _stack.resize(countNodes(*G));
alpar@100:       _stack_head=-1;
alpar@100:       for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
alpar@209:         _pred->set(u,INVALID);
alpar@209:         // _predNode->set(u,INVALID);
alpar@209:         _reached->set(u,false);
alpar@209:         _processed->set(u,false);
alpar@100:       }
alpar@100:     }
alpar@209: 
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:     ///\warning dists are wrong (or at least strange)
alpar@100:     ///in case of multiple sources.
alpar@100:     void addSource(Node s)
alpar@100:     {
alpar@100:       if(!(*_reached)[s])
alpar@209:         {
alpar@209:           _reached->set(s,true);
alpar@209:           _pred->set(s,INVALID);
alpar@209:           OutArcIt e(*G,s);
alpar@209:           if(e!=INVALID) {
alpar@209:             _stack[++_stack_head]=e;
alpar@209:             _dist->set(s,_stack_head);
alpar@209:           }
alpar@209:           else {
alpar@209:             _processed->set(s,true);
alpar@209:             _dist->set(s,0);
alpar@209:           }
alpar@209:         }
alpar@100:     }
alpar@209: 
alpar@100:     ///Processes the next arc.
alpar@100: 
alpar@100:     ///Processes the next arc.
alpar@100:     ///
alpar@100:     ///\return The processed arc.
alpar@100:     ///
alpar@100:     ///\pre The stack must not be empty!
alpar@100:     Arc processNextArc()
alpar@209:     {
alpar@100:       Node m;
alpar@100:       Arc e=_stack[_stack_head];
alpar@100:       if(!(*_reached)[m=G->target(e)]) {
alpar@209:         _pred->set(m,e);
alpar@209:         _reached->set(m,true);
alpar@209:         ++_stack_head;
alpar@209:         _stack[_stack_head] = OutArcIt(*G, m);
alpar@209:         _dist->set(m,_stack_head);
alpar@100:       }
alpar@100:       else {
alpar@209:         m=G->source(e);
alpar@209:         ++_stack[_stack_head];
alpar@100:       }
alpar@100:       while(_stack_head>=0 && _stack[_stack_head]==INVALID) {
alpar@209:         _processed->set(m,true);
alpar@209:         --_stack_head;
alpar@209:         if(_stack_head>=0) {
alpar@209:           m=G->source(_stack[_stack_head]);
alpar@209:           ++_stack[_stack_head];
alpar@209:         }
alpar@100:       }
alpar@100:       return e;
alpar@100:     }
alpar@100:     ///Next arc to be processed.
alpar@100: 
alpar@100:     ///Next arc to be processed.
alpar@100:     ///
alpar@100:     ///\return The next arc to be processed or INVALID if the stack is
alpar@100:     /// empty.
alpar@100:     OutArcIt nextArc()
alpar@209:     {
alpar@100:       return _stack_head>=0?_stack[_stack_head]: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 _stack_head<0; }
alpar@100:     ///Returns the number of the nodes to be processed.
alpar@209: 
alpar@100:     ///Returns the number of the nodes to be processed in the queue.
alpar@100:     int queueSize() { return _stack_head+1; }
alpar@209: 
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 %DFS algorithm from the root node(s)
alpar@100:     ///in order to
alpar@100:     ///compute the
alpar@100:     ///%DFS path to each node. The algorithm computes
alpar@100:     ///- The %DFS tree.
alpar@100:     ///- The distance of each node from the root(s) in the %DFS tree.
alpar@100:     ///
alpar@100:     void start()
alpar@100:     {
alpar@100:       while ( !emptyQueue() ) processNextArc();
alpar@100:     }
alpar@209: 
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 %DFS algorithm from the root node(s)
alpar@100:     ///in order to
alpar@100:     ///compute the
alpar@100:     ///%DFS path to \c dest. The algorithm computes
alpar@100:     ///- The %DFS path to \c  dest.
alpar@100:     ///- The distance of \c dest from the root(s) in the %DFS tree.
alpar@100:     ///
alpar@100:     void start(Node dest)
alpar@100:     {
alpar@209:       while ( !emptyQueue() && G->target(_stack[_stack_head])!=dest )
alpar@209:         processNextArc();
alpar@100:     }
alpar@209: 
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 em must be a bool (or convertible) arc map. The algorithm
alpar@100:     ///will stop when it reaches an arc \c e with <tt>em[e]</tt> true.
alpar@100:     ///
alpar@100:     ///\return The reached arc \c e with <tt>em[e]</tt> true or
alpar@100:     ///\c INVALID if no such arc was found.
alpar@100:     ///
alpar@100:     ///\warning Contrary to \ref Bfs and \ref Dijkstra, \c em is an arc map,
alpar@100:     ///not a node map.
alpar@100:     template<class EM>
alpar@100:     Arc start(const EM &em)
alpar@100:     {
alpar@100:       while ( !emptyQueue() && !em[_stack[_stack_head]] )
alpar@100:         processNextArc();
alpar@100:       return emptyQueue() ? INVALID : _stack[_stack_head];
alpar@100:     }
alpar@100: 
alpar@100:     ///Runs %DFS algorithm to visit all nodes in the digraph.
alpar@209: 
alpar@100:     ///This method runs the %DFS algorithm in order to
alpar@100:     ///compute the
alpar@100:     ///%DFS path to each node. The algorithm computes
alpar@100:     ///- The %DFS tree.
alpar@100:     ///- The distance of each node from the root in the %DFS tree.
alpar@100:     ///
alpar@100:     ///\note d.run() is just a shortcut of the following code.
alpar@100:     ///\code
alpar@100:     ///  d.init();
alpar@100:     ///  for (NodeIt it(digraph); it != INVALID; ++it) {
alpar@100:     ///    if (!d.reached(it)) {
alpar@100:     ///      d.addSource(it);
alpar@100:     ///      d.start();
alpar@100:     ///    }
alpar@100:     ///  }
alpar@100:     ///\endcode
alpar@100:     void run() {
alpar@100:       init();
alpar@100:       for (NodeIt it(*G); 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:     ///Runs %DFS algorithm from node \c s.
alpar@209: 
alpar@100:     ///This method runs the %DFS algorithm from a root node \c s
alpar@100:     ///in order to
alpar@100:     ///compute the
alpar@100:     ///%DFS path to each node. The algorithm computes
alpar@100:     ///- The %DFS tree.
alpar@100:     ///- The distance of each node from the root in the %DFS tree.
alpar@100:     ///
alpar@100:     ///\note d.run(s) is just a shortcut of the following code.
alpar@100:     ///\code
alpar@100:     ///  d.init();
alpar@100:     ///  d.addSource(s);
alpar@100:     ///  d.start();
alpar@100:     ///\endcode
alpar@100:     void run(Node s) {
alpar@100:       init();
alpar@100:       addSource(s);
alpar@100:       start();
alpar@100:     }
alpar@209: 
alpar@100:     ///Finds the %DFS path between \c s and \c t.
alpar@209: 
alpar@100:     ///Finds the %DFS path between \c s and \c t.
alpar@100:     ///
alpar@100:     ///\return The length of the %DFS s---t path if there exists one,
alpar@100:     ///0 otherwise.
alpar@100:     ///\note Apart from the return value, d.run(s,t) is
alpar@100:     ///just a shortcut of the following code.
alpar@100:     ///\code
alpar@100:     ///  d.init();
alpar@100:     ///  d.addSource(s);
alpar@100:     ///  d.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)?_stack_head+1:0;
alpar@100:     }
alpar@209: 
alpar@100:     ///@}
alpar@100: 
alpar@100:     ///\name Query Functions
alpar@100:     ///The result of the %DFS 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@209: 
alpar@100:     ///@{
alpar@100: 
alpar@100:     typedef PredMapPath<Digraph, PredMap> Path;
alpar@100: 
alpar@100:     ///Gives back the shortest path.
alpar@209: 
alpar@100:     ///Gives back the shortest path.
alpar@100:     ///\pre The \c t should be reachable from the source.
alpar@209:     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@209:     ///\warning If node \c v is unreachable from the root(s) then the return
alpar@100:     ///value of this funcion is undefined.
alpar@100:     int dist(Node v) const { return (*_dist)[v]; }
alpar@100: 
alpar@100:     ///Returns the 'previous arc' of the %DFS tree.
alpar@100: 
alpar@100:     ///For a node \c v it returns the 'previous arc'
alpar@100:     ///of the %DFS path,
alpar@100:     ///i.e. it returns the last arc of a %DFS 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:     ///%DFS tree used here is equal to the %DFS 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 %DFS tree.
alpar@100: 
alpar@100:     ///For a node \c v it returns the 'previous node'
alpar@100:     ///of the %DFS tree,
alpar@100:     ///i.e. it returns the last but one node from a %DFS path from the
alpar@100:     ///root(s) 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 %DFS tree used here is equal to the %DFS
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@209:                                   G->source((*_pred)[v]); }
alpar@209: 
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@209: 
alpar@100:     ///Returns a reference to the %DFS arc-tree map.
alpar@100: 
alpar@100:     ///Returns a reference to the NodeMap of the arcs of the
alpar@100:     ///%DFS 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@209: 
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(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@209: 
alpar@100:     ///@}
alpar@100:   };
alpar@100: 
alpar@100:   ///Default traits class of Dfs function.
alpar@100: 
alpar@100:   ///Default traits class of Dfs function.
kpeter@157:   ///\tparam GR Digraph type.
alpar@100:   template<class GR>
alpar@100:   struct DfsWizardDefaultTraits
alpar@100:   {
alpar@209:     ///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 %DFS paths.
alpar@209:     ///
alpar@100:     ///The type of the map that stores the last
alpar@100:     ///arcs of the %DFS 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@209: 
alpar@209:     ///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@209:     static PredMap *createPredMap(const GR &g)
alpar@100: #else
alpar@209:     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@209: 
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@209: 
alpar@209:     ///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@209: 
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@209: 
alpar@209:     ///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@209: 
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@209: 
alpar@209:     ///This function instantiates a \ref DistMap.
alpar@210:     ///\param g is the digraph, to which we would like to define
alpar@210:     ///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@209: 
alpar@100:   /// Default traits used by \ref DfsWizard
alpar@100: 
alpar@100:   /// To make it easier to use Dfs algorithm
alpar@100:   ///we have created a wizard class.
alpar@100:   /// This \ref DfsWizard class needs default traits,
alpar@100:   ///as well as the \ref Dfs class.
alpar@100:   /// The \ref DfsWizardBase is a class to be the default traits of the
alpar@100:   /// \ref DfsWizard class.
alpar@100:   template<class GR>
alpar@100:   class DfsWizardBase : public DfsWizardDefaultTraits<GR>
alpar@100:   {
alpar@100: 
alpar@100:     typedef DfsWizardDefaultTraits<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@209: 
alpar@100:     public:
alpar@100:     /// Constructor.
alpar@209: 
alpar@100:     /// This constructor does not require parameters, therefore it initiates
alpar@100:     /// all of the attributes to default values (0, INVALID).
alpar@100:     DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0),
alpar@209:                            _dist(0), _source(INVALID) {}
alpar@100: 
alpar@100:     /// Constructor.
alpar@209: 
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:     DfsWizardBase(const GR &g, Node s=INVALID) :
alpar@209:       _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@209: 
alpar@100:   /// A class to make the usage of the Dfs algorithm easier
alpar@100: 
alpar@100:   /// This class is created to make it easier to use the Dfs algorithm.
alpar@100:   /// It uses the functions and features of the plain \ref Dfs,
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 Dfs
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 DfsWizard 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 Dfs object, and calls the \ref Dfs::run
alpar@100:   /// method of it.
alpar@100:   template<class TR>
alpar@100:   class DfsWizard : 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@209: 
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 %DFS paths.
alpar@100:     typedef typename TR::PredMap PredMap;
alpar@100:     ///The type of the map that stores the distances of the nodes.
alpar@100:     typedef typename TR::DistMap DistMap;
alpar@100: 
alpar@100:   public:
alpar@100:     /// Constructor.
alpar@100:     DfsWizard() : 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:     DfsWizard(const Digraph &g, Node s=INVALID) :
alpar@100:       TR(g,s) {}
alpar@100: 
alpar@100:     ///Copy constructor
alpar@100:     DfsWizard(const TR &b) : TR(b) {}
alpar@100: 
alpar@100:     ~DfsWizard() {}
alpar@100: 
alpar@100:     ///Runs Dfs algorithm from a given node.
alpar@209: 
alpar@100:     ///Runs Dfs 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:       Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g));
alpar@209:       if(Base::_reached)
alpar@100:         alg.reachedMap(*reinterpret_cast<ReachedMap*>(Base::_reached));
alpar@209:       if(Base::_processed)
alpar@100:         alg.processedMap(*reinterpret_cast<ProcessedMap*>(Base::_processed));
alpar@209:       if(Base::_pred)
alpar@100:         alg.predMap(*reinterpret_cast<PredMap*>(Base::_pred));
alpar@209:       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 Dfs algorithm from the given node.
alpar@100: 
alpar@100:     ///Runs Dfs 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@209: 
alpar@100:     ///\brief \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting PredMap type
alpar@100:     ///
alpar@100:     /// \ref named-templ-param "Named parameter"
alpar@100:     ///function for setting PredMap type
alpar@100:     ///
alpar@100:     template<class T>
alpar@209:     DfsWizard<DefPredMapBase<T> > predMap(const T &t)
alpar@100:     {
alpar@100:       Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100:       return DfsWizard<DefPredMapBase<T> >(*this);
alpar@100:     }
alpar@209: 
alpar@209: 
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@209: 
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@209:     DfsWizard<DefReachedMapBase<T> > reachedMap(const T &t)
alpar@100:     {
deba@158:       Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100:       return DfsWizard<DefReachedMapBase<T> >(*this);
alpar@100:     }
alpar@209: 
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@209: 
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@209:     DfsWizard<DefProcessedMapBase<T> > processedMap(const T &t)
alpar@100:     {
deba@158:       Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100:       return DfsWizard<DefProcessedMapBase<T> >(*this);
alpar@100:     }
alpar@209: 
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@209: 
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@209:     DfsWizard<DefDistMapBase<T> > distMap(const T &t)
alpar@100:     {
alpar@100:       Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100:       return DfsWizard<DefDistMapBase<T> >(*this);
alpar@100:     }
alpar@209: 
alpar@100:     /// Sets the source node, from which the Dfs algorithm runs.
alpar@100: 
alpar@100:     /// Sets the source node, from which the Dfs algorithm runs.
alpar@100:     /// \param s is the source node.
alpar@209:     DfsWizard<TR> &source(Node s)
alpar@100:     {
alpar@100:       Base::_source=s;
alpar@100:       return *this;
alpar@100:     }
alpar@209: 
alpar@100:   };
alpar@209: 
alpar@100:   ///Function type interface for Dfs algorithm.
alpar@100: 
alpar@100:   ///\ingroup search
alpar@100:   ///Function type interface for Dfs 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 DfsWizard.
alpar@100:   ///The following
alpar@100:   ///example shows how to use these parameters.
alpar@100:   ///\code
alpar@100:   ///  dfs(g,source).predMap(preds).run();
alpar@100:   ///\endcode
alpar@100:   ///\warning Don't forget to put the \ref DfsWizard::run() "run()"
alpar@100:   ///to the end of the parameter list.
alpar@100:   ///\sa DfsWizard
alpar@100:   ///\sa Dfs
alpar@100:   template<class GR>
alpar@100:   DfsWizard<DfsWizardBase<GR> >
alpar@100:   dfs(const GR &g,typename GR::Node s=INVALID)
alpar@100:   {
alpar@100:     return DfsWizard<DfsWizardBase<GR> >(g,s);
alpar@100:   }
alpar@100: 
alpar@100: #ifdef DOXYGEN
alpar@100:   /// \brief Visitor class for dfs.
alpar@209:   ///
alpar@209:   /// It gives a simple interface for a functional interface for dfs
alpar@209:   /// traversal. The traversal on a linear data structure.
alpar@100:   template <typename _Digraph>
alpar@100:   struct DfsVisitor {
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@209:     ///
alpar@100:     /// It is called when the dfs 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@209:     ///
alpar@100:     /// It is Called when the node reached first time.
alpar@100:     void reach(const Node& node) {}
alpar@100:     /// \brief Called when we step back on an arc.
alpar@209:     ///
alpar@100:     /// It is called when the dfs should step back on the arc.
alpar@100:     void backtrack(const Arc& arc) {}
alpar@100:     /// \brief Called when we step back from the node.
alpar@209:     ///
alpar@100:     /// It is called when we step back from the node.
alpar@100:     void leave(const Node& node) {}
alpar@209:     /// \brief Called when the arc examined but target of the arc
alpar@100:     /// already discovered.
alpar@209:     ///
alpar@209:     /// 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 dfs.
alpar@209:     ///
alpar@100:     /// It is called for the source node of the dfs.
alpar@100:     void start(const Node& node) {}
alpar@100:     /// \brief Called when we leave the source node of the dfs.
alpar@209:     ///
alpar@100:     /// It is called when we leave the source node of the dfs.
alpar@100:     void stop(const Node& node) {}
alpar@100: 
alpar@100:   };
alpar@100: #else
alpar@100:   template <typename _Digraph>
alpar@100:   struct DfsVisitor {
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 backtrack(const Arc&) {}
alpar@100:     void leave(const Node&) {}
alpar@100:     void examine(const Arc&) {}
alpar@100:     void start(const Node&) {}
alpar@100:     void stop(const Node&) {}
alpar@100: 
alpar@100:     template <typename _Visitor>
alpar@100:     struct Constraints {
alpar@100:       void constraints() {
alpar@209:         Arc arc;
alpar@209:         Node node;
alpar@209:         visitor.discover(arc);
alpar@209:         visitor.reach(node);
alpar@209:         visitor.backtrack(arc);
alpar@209:         visitor.leave(node);
alpar@209:         visitor.examine(arc);
alpar@209:         visitor.start(node);
alpar@209:         visitor.stop(arc);
alpar@100:       }
alpar@100:       _Visitor& visitor;
alpar@100:     };
alpar@100:   };
alpar@100: #endif
alpar@100: 
alpar@100:   /// \brief Default traits class of DfsVisit class.
alpar@100:   ///
alpar@100:   /// Default traits class of DfsVisit class.
kpeter@157:   /// \tparam _Digraph Digraph type.
alpar@100:   template<class _Digraph>
alpar@100:   struct DfsVisitDefaultTraits {
alpar@100: 
alpar@209:     /// \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@209:     ///
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@209:     /// 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@209: 
alpar@100:   /// %DFS Visit algorithm class.
alpar@209: 
alpar@100:   /// \ingroup search
alpar@100:   /// This class provides an efficient implementation of the %DFS algorithm
alpar@100:   /// with visitor interface.
alpar@100:   ///
alpar@100:   /// The %DfsVisit class provides an alternative interface to the Dfs
alpar@100:   /// class. It works with callback mechanism, the DfsVisit object calls
alpar@209:   /// on every dfs event the \c Visitor class member functions.
alpar@100:   ///
alpar@210:   /// \tparam _Digraph The digraph type the algorithm runs on.
alpar@210:   /// The default value is
alpar@100:   /// \ref ListDigraph. The value of _Digraph is not used directly by Dfs, it
alpar@100:   /// is only passed to \ref DfsDefaultTraits.
alpar@209:   /// \tparam _Visitor The Visitor object for the algorithm. The
alpar@100:   /// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty Visitor which
alpar@100:   /// does not observe the Dfs events. If you want to observe the dfs
alpar@100:   /// events you should implement your own Visitor class.
alpar@209:   /// \tparam _Traits Traits class to set various data types used by the
alpar@100:   /// algorithm. The default traits class is
alpar@100:   /// \ref DfsVisitDefaultTraits "DfsVisitDefaultTraits<_Digraph>".
alpar@100:   /// See \ref DfsVisitDefaultTraits for the documentation of
alpar@100:   /// a Dfs visit traits class.
alpar@100:   ///
alpar@100:   /// \author Jacint Szabo, Alpar Juttner and Balazs Dezso
alpar@100: #ifdef DOXYGEN
alpar@100:   template <typename _Digraph, typename _Visitor, typename _Traits>
alpar@100: #else
alpar@100:   template <typename _Digraph = ListDigraph,
alpar@209:             typename _Visitor = DfsVisitor<_Digraph>,
alpar@209:             typename _Traits = DfsDefaultTraits<_Digraph> >
alpar@100: #endif
alpar@100:   class DfsVisit {
alpar@100:   public:
alpar@209: 
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@209:       virtual const char* what() const throw()
alpar@100:       {
alpar@209:         return "lemon::DfsVisit::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::Arc> _stack;
alpar@100:     int _stack_head;
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@209:         local_reached = true;
alpar@209:         _reached = Traits::createReachedMap(*_digraph);
alpar@100:       }
alpar@100:     }
alpar@100: 
alpar@100:   protected:
alpar@100: 
alpar@100:     DfsVisit() {}
alpar@209: 
alpar@100:   public:
alpar@100: 
alpar@100:     typedef DfsVisit 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@209:         throw UninitializedParameter();
alpar@100:       }
alpar@100:     };
alpar@209:     /// \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 DfsVisit< Digraph, Visitor,
alpar@209:                                             DefReachedMapTraits<T> > {
alpar@100:       typedef DfsVisit< Digraph, Visitor, DefReachedMapTraits<T> > Create;
alpar@100:     };
alpar@100:     ///@}
alpar@100: 
alpar@209:   public:
alpar@209: 
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@209:     DfsVisit(const Digraph& digraph, Visitor& visitor)
alpar@100:       : _digraph(&digraph), _visitor(&visitor),
alpar@209:         _reached(0), local_reached(false) {}
alpar@209: 
alpar@100:     /// \brief Destructor.
alpar@100:     ///
alpar@100:     /// Destructor.
alpar@100:     ~DfsVisit() {
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:     DfsVisit &reachedMap(ReachedMap &m) {
alpar@100:       if(local_reached) {
alpar@209:         delete _reached;
alpar@209:         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:       _stack.resize(countNodes(*_digraph));
alpar@100:       _stack_head = -1;
alpar@100:       for (NodeIt u(*_digraph) ; u != INVALID ; ++u) {
alpar@209:         _reached->set(u, false);
alpar@100:       }
alpar@100:     }
alpar@209: 
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@209:           _reached->set(s,true);
alpar@209:           _visitor->start(s);
alpar@209:           _visitor->reach(s);
alpar@209:           Arc e;
alpar@209:           _digraph->firstOut(e, s);
alpar@209:           if (e != INVALID) {
alpar@209:             _stack[++_stack_head] = e;
alpar@209:           } else {
alpar@209:             _visitor->leave(s);
alpar@209:           }
alpar@209:         }
alpar@100:     }
alpar@209: 
alpar@100:     /// \brief Processes the next arc.
alpar@100:     ///
alpar@100:     /// Processes the next arc.
alpar@100:     ///
alpar@100:     /// \return The processed arc.
alpar@100:     ///
alpar@100:     /// \pre The stack must not be empty!
alpar@209:     Arc processNextArc() {
alpar@100:       Arc e = _stack[_stack_head];
alpar@100:       Node m = _digraph->target(e);
alpar@100:       if(!(*_reached)[m]) {
alpar@209:         _visitor->discover(e);
alpar@209:         _visitor->reach(m);
alpar@209:         _reached->set(m, true);
alpar@209:         _digraph->firstOut(_stack[++_stack_head], m);
alpar@100:       } else {
alpar@209:         _visitor->examine(e);
alpar@209:         m = _digraph->source(e);
alpar@209:         _digraph->nextOut(_stack[_stack_head]);
alpar@100:       }
alpar@100:       while (_stack_head>=0 && _stack[_stack_head] == INVALID) {
alpar@209:         _visitor->leave(m);
alpar@209:         --_stack_head;
alpar@209:         if (_stack_head >= 0) {
alpar@209:           _visitor->backtrack(_stack[_stack_head]);
alpar@209:           m = _digraph->source(_stack[_stack_head]);
alpar@209:           _digraph->nextOut(_stack[_stack_head]);
alpar@209:         } else {
alpar@209:           _visitor->stop(m);
alpar@209:         }
alpar@100:       }
alpar@100:       return e;
alpar@100:     }
alpar@100: 
alpar@100:     /// \brief Next arc to be processed.
alpar@100:     ///
alpar@100:     /// Next arc to be processed.
alpar@100:     ///
alpar@100:     /// \return The next arc to be processed or INVALID if the stack is
alpar@100:     /// empty.
alpar@209:     Arc nextArc() {
alpar@100:       return _stack_head >= 0 ? _stack[_stack_head] : 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 _stack_head < 0; }
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 _stack_head + 1; }
alpar@209: 
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() ) processNextArc();
alpar@100:     }
alpar@209: 
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@209:       while ( !emptyQueue() && _digraph->target(_stack[_stack_head]) != dest )
alpar@209:         processNextArc();
alpar@100:     }
alpar@209: 
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 em must be a bool (or convertible) arc map. The algorithm
alpar@100:     /// will stop when it reaches an arc \c e with <tt>em[e]</tt> true.
alpar@100:     ///
alpar@100:     ///\return The reached arc \c e with <tt>em[e]</tt> true or
alpar@100:     ///\c INVALID if no such arc was found.
alpar@100:     ///
alpar@100:     /// \warning Contrary to \ref Bfs and \ref Dijkstra, \c em is an arc map,
alpar@100:     /// not a node map.
alpar@100:     template <typename EM>
alpar@100:     Arc start(const EM &em) {
alpar@100:       while ( !emptyQueue() && !em[_stack[_stack_head]] )
alpar@100:         processNextArc();
alpar@100:       return emptyQueue() ? INVALID : _stack[_stack_head];
alpar@100:     }
alpar@100: 
alpar@100:     /// \brief Runs %DFSVisit algorithm from node \c s.
alpar@100:     ///
alpar@100:     /// This method runs the %DFS algorithm from a root node \c s.
alpar@100:     /// \note d.run(s) is just a shortcut of the following code.
alpar@100:     ///\code
alpar@100:     ///   d.init();
alpar@100:     ///   d.addSource(s);
alpar@100:     ///   d.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 %DFSVisit algorithm to visit all nodes in the digraph.
alpar@209: 
alpar@100:     /// This method runs the %DFS algorithm in order to
alpar@100:     /// compute the %DFS path to each node. The algorithm computes
alpar@100:     /// - The %DFS tree.
alpar@100:     /// - The distance of each node from the root in the %DFS tree.
alpar@100:     ///
alpar@100:     ///\note d.run() is just a shortcut of the following code.
alpar@100:     ///\code
alpar@100:     ///  d.init();
alpar@100:     ///  for (NodeIt it(digraph); it != INVALID; ++it) {
alpar@100:     ///    if (!d.reached(it)) {
alpar@100:     ///      d.addSource(it);
alpar@100:     ///      d.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 %DFS 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:     /// \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: 
alpar@100: } //END OF NAMESPACE LEMON
alpar@100: 
alpar@100: #endif
alpar@100: