lemon-main: comparison lemon/dfs.h

equal deleted inserted replaced

-:71c95333b7dd
+:3a36b024931f
 #ifndef LEMON_DFS_H
 #define LEMON_DFS_H
 ///\ingroup search
 ///\file
-///\brief Dfs algorithm.
+///\brief DFS algorithm.
 #include <lemon/list_graph.h>
 #include <lemon/bits/path_dump.h>
 #include <lemon/core.h>
 #include <lemon/error.h>
+#include <lemon/assert.h>
 #include <lemon/maps.h>
-#include <lemon/concept_check.h>
 namespace lemon {
 ///Default traits class of Dfs class.
 ///Default traits class of Dfs class.
 ///\tparam GR Digraph type.
 template<class GR>
 struct DfsDefaultTraits
 {
-///The digraph type the algorithm runs on.
+///The type of the digraph the algorithm runs on.
 typedef GR Digraph;
-///\brief The type of the map that stores the last
+///\brief The type of the map that stores the predecessor
 ///arcs of the %DFS paths.
 ///
-///The type of the map that stores the last
+///The type of the map that stores the predecessor
 ///arcs of the %DFS paths.
 ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
-///
+typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap;
-typedef typename Digraph::template NodeMap<typename GR::Arc> PredMap;
+///Instantiates a \ref PredMap.
-///Instantiates a PredMap.
 ///This function instantiates a \ref PredMap.
-///\param G is the digraph, to which we would like to define the PredMap.
+///\param g is the digraph, to which we would like to define the
+///\ref PredMap.
 ///\todo The digraph alone may be insufficient to initialize
-static PredMap *createPredMap(const GR &G)
+static PredMap *createPredMap(const Digraph &g)
 {
-return new PredMap(G);
+return new PredMap(g);
 }
 ///The type of the map that indicates which nodes are processed.
 ///The type of the map that indicates which nodes are processed.
 ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
-///\todo named parameter to set this type, function to read and write.
+///By default it is a NullMap.
 typedef NullMap<typename Digraph::Node,bool> ProcessedMap;
-///Instantiates a ProcessedMap.
+///Instantiates a \ref ProcessedMap.
 ///This function instantiates a \ref ProcessedMap.
 ///\param g is the digraph, to which
 ///we would like to define the \ref ProcessedMap
 #ifdef DOXYGEN
-static ProcessedMap *createProcessedMap(const GR &g)
+static ProcessedMap *createProcessedMap(const Digraph &g)
 #else
-static ProcessedMap *createProcessedMap(const GR &)
+static ProcessedMap *createProcessedMap(const Digraph &)
 #endif
 {
 return new ProcessedMap();
 }
 ///The type of the map that indicates which nodes are reached.
 ///The type of the map that indicates which nodes are reached.
+///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept.
+typedef typename Digraph::template NodeMap<bool> ReachedMap;
+///Instantiates a \ref ReachedMap.
+///This function instantiates a \ref ReachedMap.
+///\param g is the digraph, to which
+///we would like to define the \ref ReachedMap.
+static ReachedMap *createReachedMap(const Digraph &g)
+{
+return new ReachedMap(g);
+}
+///The type of the map that stores the distances of the nodes.
+///The type of the map that stores the distances of the nodes.
 ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
-///\todo named parameter to set this type, function to read and write.
-typedef typename Digraph::template NodeMap<bool> ReachedMap;
-///Instantiates a ReachedMap.
-///This function instantiates a \ref ReachedMap.
-///\param G is the digraph, to which
-///we would like to define the \ref ReachedMap.
-static ReachedMap *createReachedMap(const GR &G)
-{
-return new ReachedMap(G);
-}
-///The type of the map that stores the dists of the nodes.
-///The type of the map that stores the dists of the nodes.
-///It must meet the \ref concepts::WriteMap "WriteMap" concept.
-///
 typedef typename Digraph::template NodeMap<int> DistMap;
-///Instantiates a DistMap.
+///Instantiates a \ref DistMap.
 ///This function instantiates a \ref DistMap.
-///\param G is the digraph, to which we would like to define
+///\param g is the digraph, to which we would like to define the
-///the \ref DistMap
+///\ref DistMap.
-static DistMap *createDistMap(const GR &G)
+static DistMap *createDistMap(const Digraph &g)
 {
-return new DistMap(G);
+return new DistMap(g);
 }
 };
 ///%DFS algorithm class.
 ///\ingroup search
 ///This class provides an efficient implementation of the %DFS algorithm.
 ///
-///\tparam GR The digraph type the algorithm runs on. The default value is
+///There is also a \ref dfs() "function type interface" for the DFS
-///\ref ListDigraph. The value of GR is not used directly by Dfs, it
+///algorithm, which is convenient in the simplier cases and it can be
-///is only passed to \ref DfsDefaultTraits.
+///used easier.
+///
+///\tparam GR The type of the digraph the algorithm runs on.
+///The default value is \ref ListDigraph. The value of GR is not used
+///directly by \ref Dfs, it is only passed to \ref DfsDefaultTraits.
 ///\tparam TR Traits class to set various data types used by the algorithm.
 ///The default traits class is
 ///\ref DfsDefaultTraits "DfsDefaultTraits<GR>".
 ///See \ref DfsDefaultTraits for the documentation of
 ///a Dfs traits class.
 template <typename GR=ListDigraph,
 typename TR=DfsDefaultTraits<GR> >
 #endif
 class Dfs {
 public:
-/**
+///\ref Exception for uninitialized parameters.
-* \brief \ref Exception for uninitialized parameters.
-*
+///This error represents problems in the initialization of the
-* This error represents problems in the initialization
+///parameters of the algorithm.
-* of the parameters of the algorithms.
-*/
 class UninitializedParameter : public lemon::UninitializedParameter {
 public:
 virtual const char* what() const throw() {
 return "lemon::Dfs::UninitializedParameter";
 }
 };
+///The type of the digraph the algorithm runs on.
+typedef typename TR::Digraph Digraph;
+///\brief The type of the map that stores the predecessor arcs of the
+///DFS paths.
+typedef typename TR::PredMap PredMap;
+///The type of the map that stores the distances of the nodes.
+typedef typename TR::DistMap DistMap;
+///The type of the map that indicates which nodes are reached.
+typedef typename TR::ReachedMap ReachedMap;
+///The type of the map that indicates which nodes are processed.
+typedef typename TR::ProcessedMap ProcessedMap;
+///The type of the paths.
+typedef PredMapPath<Digraph, PredMap> Path;
+///The traits class.
 typedef TR Traits;
-///The type of the underlying digraph.
-typedef typename TR::Digraph Digraph;
+private:
-///\e
 typedef typename Digraph::Node Node;
-///\e
 typedef typename Digraph::NodeIt NodeIt;
-///\e
 typedef typename Digraph::Arc Arc;
-///\e
 typedef typename Digraph::OutArcIt OutArcIt;
-///\brief The type of the map that stores the last
+//Pointer to the underlying digraph.
-///arcs of the %DFS paths.
-typedef typename TR::PredMap PredMap;
-///The type of the map indicating which nodes are reached.
-typedef typename TR::ReachedMap ReachedMap;
-///The type of the map indicating which nodes are processed.
-typedef typename TR::ProcessedMap ProcessedMap;
-///The type of the map that stores the dists of the nodes.
-typedef typename TR::DistMap DistMap;
-private:
-/// Pointer to the underlying digraph.
 const Digraph *G;
-///Pointer to the map of predecessors arcs.
+//Pointer to the map of predecessor arcs.
 PredMap *_pred;
-///Indicates if \ref _pred is locally allocated (\c true) or not.
+//Indicates if _pred is locally allocated (true) or not.
 bool local_pred;
-///Pointer to the map of distances.
+//Pointer to the map of distances.
 DistMap *_dist;
-///Indicates if \ref _dist is locally allocated (\c true) or not.
+//Indicates if _dist is locally allocated (true) or not.
 bool local_dist;
-///Pointer to the map of reached status of the nodes.
+//Pointer to the map of reached status of the nodes.
 ReachedMap *_reached;
-///Indicates if \ref _reached is locally allocated (\c true) or not.
+//Indicates if _reached is locally allocated (true) or not.
 bool local_reached;
-///Pointer to the map of processed status of the nodes.
+//Pointer to the map of processed status of the nodes.
 ProcessedMap *_processed;
-///Indicates if \ref _processed is locally allocated (\c true) or not.
+//Indicates if _processed is locally allocated (true) or not.
 bool local_processed;
 std::vector<typename Digraph::OutArcIt> _stack;
 int _stack_head;
 ///Creates the maps if necessary.
 ///\todo Better memory allocation (instead of new).
 void create_maps()
 {
 if(!_pred) {
 local_pred = true;
 ///@{
 template <class T>
 struct DefPredMapTraits : public Traits {
 typedef T PredMap;
-static PredMap *createPredMap(const Digraph &G)
+static PredMap *createPredMap(const Digraph &)
 {
 throw UninitializedParameter();
 }
 };
 ///\brief \ref named-templ-param "Named parameter" for setting
-///PredMap type
+///\ref PredMap type.
 ///
-///\ref named-templ-param "Named parameter" for setting PredMap type
+///\ref named-templ-param "Named parameter" for setting
-///
+///\ref PredMap type.
 template <class T>
 struct DefPredMap : public Dfs<Digraph, DefPredMapTraits<T> > {
 typedef Dfs<Digraph, DefPredMapTraits<T> > Create;
 };
 template <class T>
 struct DefDistMapTraits : public Traits {
 typedef T DistMap;
 static DistMap *createDistMap(const Digraph &)
 {
 throw UninitializedParameter();
 }
 };
 ///\brief \ref named-templ-param "Named parameter" for setting
-///DistMap type
+///\ref DistMap type.
 ///
-///\ref named-templ-param "Named parameter" for setting DistMap
+///\ref named-templ-param "Named parameter" for setting
-///type
+///\ref DistMap type.
 template <class T>
-struct DefDistMap {
+struct DefDistMap : public Dfs< Digraph, DefDistMapTraits<T> > {
 typedef Dfs<Digraph, DefDistMapTraits<T> > Create;
 };
 template <class T>
 struct DefReachedMapTraits : public Traits {
 {
 throw UninitializedParameter();
 }
 };
 ///\brief \ref named-templ-param "Named parameter" for setting
-///ReachedMap type
+///\ref ReachedMap type.
 ///
-///\ref named-templ-param "Named parameter" for setting ReachedMap type
+///\ref named-templ-param "Named parameter" for setting
-///
+///\ref ReachedMap type.
 template <class T>
 struct DefReachedMap : public Dfs< Digraph, DefReachedMapTraits<T> > {
 typedef Dfs< Digraph, DefReachedMapTraits<T> > Create;
 };
 {
 throw UninitializedParameter();
 }
 };
 ///\brief \ref named-templ-param "Named parameter" for setting
-///ProcessedMap type
+///\ref ProcessedMap type.
 ///
-///\ref named-templ-param "Named parameter" for setting ProcessedMap type
+///\ref named-templ-param "Named parameter" for setting
-///
+///\ref ProcessedMap type.
 template <class T>
 struct DefProcessedMap : public Dfs< Digraph, DefProcessedMapTraits<T> > {
 typedef Dfs< Digraph, DefProcessedMapTraits<T> > Create;
 };
 struct DefDigraphProcessedMapTraits : public Traits {
 typedef typename Digraph::template NodeMap<bool> ProcessedMap;
-static ProcessedMap *createProcessedMap(const Digraph &G)
+static ProcessedMap *createProcessedMap(const Digraph &g)
 {
-return new ProcessedMap(G);
+return new ProcessedMap(g);
 }
 };
-///\brief \ref named-templ-param "Named parameter"
+///\brief \ref named-templ-param "Named parameter" for setting
-///for setting the ProcessedMap type to be Digraph::NodeMap<bool>.
+///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>.
 ///
-///\ref named-templ-param "Named parameter"
+///\ref named-templ-param "Named parameter" for setting
-///for setting the ProcessedMap type to be Digraph::NodeMap<bool>.
+///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>.
-///If you don't set it explicitely, it will be automatically allocated.
+///If you don't set it explicitly, it will be automatically allocated.
 template <class T>
-class DefProcessedMapToBeDefaultMap :
+struct DefProcessedMapToBeDefaultMap :
 public Dfs< Digraph, DefDigraphProcessedMapTraits> {
 typedef Dfs< Digraph, DefDigraphProcessedMapTraits> Create;
 };
 ///@}
 public:
 ///Constructor.
-///\param _G the digraph the algorithm will run on.
+///Constructor.
-///
+///\param g The digraph the algorithm runs on.
-Dfs(const Digraph& _G) :
+Dfs(const Digraph &g) :
-G(&_G),
+G(&g),
 _pred(NULL), local_pred(false),
 _dist(NULL), local_dist(false),
 _reached(NULL), local_reached(false),
 _processed(NULL), local_processed(false)
 { }
 if(local_dist) delete _dist;
 if(local_reached) delete _reached;
 if(local_processed) delete _processed;
 }
-///Sets the map storing the predecessor arcs.
+///Sets the map that stores the predecessor arcs.
-///Sets the map storing the predecessor arcs.
+///Sets the map that stores the predecessor arcs.
 ///If you don't use this function before calling \ref run(),
-///it will allocate one. The destuctor deallocates this
+///it will allocate one. The destructor deallocates this
 ///automatically allocated map, of course.
 ///\return <tt> (*this) </tt>
 Dfs &predMap(PredMap &m)
 {
 if(local_pred) {
 }
 _pred = &m;
 return *this;
 }
-///Sets the map storing the distances calculated by the algorithm.
+///Sets the map that indicates which nodes are reached.
-///Sets the map storing the distances calculated by the algorithm.
+///Sets the map that indicates which nodes are reached.
 ///If you don't use this function before calling \ref run(),
-///it will allocate one. The destuctor deallocates this
+///it will allocate one. The destructor deallocates this
+///automatically allocated map, of course.
+///\return <tt> (*this) </tt>
+Dfs &reachedMap(ReachedMap &m)
+{
+if(local_reached) {
+delete _reached;
+local_reached=false;
+}
+_reached = &m;
+return *this;
+}
+///Sets the map that indicates which nodes are processed.
+///Sets the map that indicates which nodes are processed.
+///If you don't use this function before calling \ref run(),
+///it will allocate one. The destructor deallocates this
+///automatically allocated map, of course.
+///\return <tt> (*this) </tt>
+Dfs &processedMap(ProcessedMap &m)
+{
+if(local_processed) {
+delete _processed;
+local_processed=false;
+}
+_processed = &m;
+return *this;
+}
+///Sets the map that stores the distances of the nodes.
+///Sets the map that stores the distances of the nodes calculated by
+///the algorithm.
+///If you don't use this function before calling \ref run(),
+///it will allocate one. The destructor deallocates this
 ///automatically allocated map, of course.
 ///\return <tt> (*this) </tt>
 Dfs &distMap(DistMap &m)
 {
 if(local_dist) {
 }
 _dist = &m;
 return *this;
 }
-///Sets the map indicating if a node is reached.
-///Sets the map indicating if a node is reached.
-///If you don't use this function before calling \ref run(),
-///it will allocate one. The destuctor deallocates this
-///automatically allocated map, of course.
-///\return <tt> (*this) </tt>
-Dfs &reachedMap(ReachedMap &m)
-{
-if(local_reached) {
-delete _reached;
-local_reached=false;
-}
-_reached = &m;
-return *this;
-}
-///Sets the map indicating if a node is processed.
-///Sets the map indicating if a node is processed.
-///If you don't use this function before calling \ref run(),
-///it will allocate one. The destuctor deallocates this
-///automatically allocated map, of course.
-///\return <tt> (*this) </tt>
-Dfs &processedMap(ProcessedMap &m)
-{
-if(local_processed) {
-delete _processed;
-local_processed=false;
-}
-_processed = &m;
-return *this;
-}
 public:
 ///\name Execution control
 ///The simplest way to execute the algorithm is to use
-///one of the member functions called \c run(...).
+///one of the member functions called \ref lemon::Dfs::run() "run()".
 ///\n
-///If you need more control on the execution,
+///If you need more control on the execution, first you must call
-///first you must call \ref init(), then you can add a source node
+///\ref lemon::Dfs::init() "init()", then you can add a source node
-///with \ref addSource().
+///with \ref lemon::Dfs::addSource() "addSource()".
-///Finally \ref start() will perform the actual path
+///Finally \ref lemon::Dfs::start() "start()" will perform the
-///computation.
+///actual path computation.
 ///@{
 ///Initializes the internal data structures.
 create_maps();
 _stack.resize(countNodes(*G));
 _stack_head=-1;
 for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
 _pred->set(u,INVALID);
-// _predNode->set(u,INVALID);
 _reached->set(u,false);
 _processed->set(u,false);
 }
 }
 ///Adds a new source node.
 ///Adds a new source node to the set of nodes to be processed.
 ///
-///\warning dists are wrong (or at least strange)
+///\pre The stack must be empty. (Otherwise the algorithm gives
-///in case of multiple sources.
+///false results.)
+///
+///\warning Distances will be wrong (or at least strange) in case of
+///multiple sources.
 void addSource(Node s)
 {
+LEMON_DEBUG(emptyQueue(), "The stack is not empty.");
 if(!(*_reached)[s])
 {
 _reached->set(s,true);
 _pred->set(s,INVALID);
 OutArcIt e(*G,s);
 ///Processes the next arc.
 ///
 ///\return The processed arc.
 ///
-///\pre The stack must not be empty!
+///\pre The stack must not be empty.
 Arc processNextArc()
 {
 Node m;
 Arc e=_stack[_stack_head];
 if(!(*_reached)[m=G->target(e)]) {
 ++_stack[_stack_head];
 }
 }
 return e;
 }
 ///Next arc to be processed.
 ///Next arc to be processed.
 ///
-///\return The next arc to be processed or INVALID if the stack is
+///\return The next arc to be processed or \c INVALID if the stack
-/// empty.
+///is empty.
-OutArcIt nextArc()
+OutArcIt nextArc() const
 {
 return _stack_head>=0?_stack[_stack_head]:INVALID;
 }
 ///\brief Returns \c false if there are nodes
-///to be processed in the queue
+///to be processed.
 ///
 ///Returns \c false if there are nodes
-///to be processed in the queue
+///to be processed in the queue (stack).
-bool emptyQueue() { return _stack_head<0; }
+bool emptyQueue() const { return _stack_head<0; }
 ///Returns the number of the nodes to be processed.
-///Returns the number of the nodes to be processed in the queue.
+///Returns the number of the nodes to be processed in the queue (stack).
-int queueSize() { return _stack_head+1; }
+int queueSize() const { return _stack_head+1; }
 ///Executes the algorithm.
 ///Executes the algorithm.
 ///
-///\pre init() must be called and at least one node should be added
+///This method runs the %DFS algorithm from the root node
-///with addSource() before using this function.
+///in order to compute the DFS path to each node.
 ///
-///This method runs the %DFS algorithm from the root node(s)
+/// The algorithm computes
-///in order to
+///- the %DFS tree,
-///compute the
+///- the distance of each node from the root in the %DFS tree.
-///%DFS path to each node. The algorithm computes
+///
-///- The %DFS tree.
+///\pre init() must be called and a root node should be
-///- The distance of each node from the root(s) in the %DFS tree.
+///added with addSource() before using this function.
 ///
+///\note <tt>d.start()</tt> is just a shortcut of the following code.
+///\code
+///  while ( !d.emptyQueue() ) {
+///    d.processNextArc();
+///  }
+///\endcode
 void start()
 {
 while ( !emptyQueue() ) processNextArc();
 }
-///Executes the algorithm until \c dest is reached.
+///Executes the algorithm until the given target node is reached.
-///Executes the algorithm until \c dest is reached.
+///Executes the algorithm until the given target node is reached.
 ///
-///\pre init() must be called and at least one node should be added
+///This method runs the %DFS algorithm from the root node
-///with addSource() before using this function.
+///in order to compute the DFS path to \c dest.
 ///
-///This method runs the %DFS algorithm from the root node(s)
+///The algorithm computes
-///in order to
+///- the %DFS path to \c dest,
-///compute the
+///- the distance of \c dest from the root in the %DFS tree.
-///%DFS path to \c dest. The algorithm computes
+///
-///- The %DFS path to \c  dest.
+///\pre init() must be called and a root node should be
-///- The distance of \c dest from the root(s) in the %DFS tree.
+///added with addSource() before using this function.
-///
 void start(Node dest)
 {
 while ( !emptyQueue() && G->target(_stack[_stack_head])!=dest )
 processNextArc();
 }
 ///Executes the algorithm until a condition is met.
 ///Executes the algorithm until a condition is met.
 ///
-///\pre init() must be called and at least one node should be added
+///This method runs the %DFS algorithm from the root node
-///with addSource() before using this function.
+///until an arc \c a with <tt>am[a]</tt> true is found.
 ///
-///\param em must be a bool (or convertible) arc map. The algorithm
+///\param am A \c bool (or convertible) arc map. The algorithm
-///will stop when it reaches an arc \c e with <tt>em[e]</tt> true.
+///will stop when it reaches an arc \c a with <tt>am[a]</tt> true.
 ///
-///\return The reached arc \c e with <tt>em[e]</tt> true or
+///\return The reached arc \c a with <tt>am[a]</tt> true or
 ///\c INVALID if no such arc was found.
 ///
-///\warning Contrary to \ref Bfs and \ref Dijkstra, \c em is an arc map,
+///\pre init() must be called and a root node should be
+///added with addSource() before using this function.
+///
+///\warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map,
 ///not a node map.
-template<class EM>
+template<class ArcBoolMap>
-Arc start(const EM &em)
+Arc start(const ArcBoolMap &am)
 {
-while ( !emptyQueue() && !em[_stack[_stack_head]] )
+while ( !emptyQueue() && !am[_stack[_stack_head]] )
 processNextArc();
 return emptyQueue() ? INVALID : _stack[_stack_head];
 }
-///Runs %DFS algorithm to visit all nodes in the digraph.
+///Runs the algorithm from the given node.
-///This method runs the %DFS algorithm in order to
+///This method runs the %DFS algorithm from node \c s
-///compute the
+///in order to compute the DFS path to each node.
-///%DFS path to each node. The algorithm computes
+///
-///- The %DFS tree.
+///The algorithm computes
-///- The distance of each node from the root in the %DFS tree.
+///- the %DFS tree,
-///
+///- the distance of each node from the root in the %DFS tree.
-///\note d.run() is just a shortcut of the following code.
+///
+///\note <tt>d.run(s)</tt> is just a shortcut of the following code.
 ///\code
 ///  d.init();
-///  for (NodeIt it(digraph); it != INVALID; ++it) {
+///  d.addSource(s);
-///    if (!d.reached(it)) {
+///  d.start();
-///      d.addSource(it);
+///\endcode
+void run(Node s) {
+init();
+addSource(s);
+start();
+}
+///Finds the %DFS path between \c s and \c t.
+///This method runs the %DFS algorithm from node \c s
+///in order to compute the DFS path to \c t.
+///
+///\return The length of the <tt>s</tt>--<tt>t</tt> DFS path,
+///if \c t is reachable form \c s, \c 0 otherwise.
+///
+///\note Apart from the return value, <tt>d.run(s,t)</tt> is
+///just a shortcut of the following code.
+///\code
+///  d.init();
+///  d.addSource(s);
+///  d.start(t);
+///\endcode
+int run(Node s,Node t) {
+init();
+addSource(s);
+start(t);
+return reached(t)?_stack_head+1:0;
+}
+///Runs the algorithm to visit all nodes in the digraph.
+///This method runs the %DFS algorithm in order to compute the
+///%DFS path to each node.
+///
+///The algorithm computes
+///- the %DFS tree,
+///- the distance of each node from the root in the %DFS tree.
+///
+///\note <tt>d.run()</tt> is just a shortcut of the following code.
+///\code
+///  d.init();
+///  for (NodeIt n(digraph); n != INVALID; ++n) {
+///    if (!d.reached(n)) {
+///      d.addSource(n);
 ///      d.start();
 ///    }
 ///  }
 ///\endcode
 void run() {
 start();
 }
 }
 }
-///Runs %DFS algorithm from node \c s.
-///This method runs the %DFS algorithm from a root node \c s
-///in order to
-///compute the
-///%DFS path to each node. The algorithm computes
-///- The %DFS tree.
-///- The distance of each node from the root in the %DFS tree.
-///
-///\note d.run(s) is just a shortcut of the following code.
-///\code
-///  d.init();
-///  d.addSource(s);
-///  d.start();
-///\endcode
-void run(Node s) {
-init();
-addSource(s);
-start();
-}
-///Finds the %DFS path between \c s and \c t.
-///Finds the %DFS path between \c s and \c t.
-///
-///\return The length of the %DFS s---t path if there exists one,
-///0 otherwise.
-///\note Apart from the return value, d.run(s,t) is
-///just a shortcut of the following code.
-///\code
-///  d.init();
-///  d.addSource(s);
-///  d.start(t);
-///\endcode
-int run(Node s,Node t) {
-init();
-addSource(s);
-start(t);
-return reached(t)?_stack_head+1:0;
-}
 ///@}
 ///\name Query Functions
 ///The result of the %DFS algorithm can be obtained using these
 ///functions.\n
-///Before the use of these functions,
+///Either \ref lemon::Dfs::run() "run()" or \ref lemon::Dfs::start()
-///either run() or start() must be called.
+///"start()" must be called before using them.
 ///@{
-typedef PredMapPath<Digraph, PredMap> Path;
+///The DFS path to a node.
-///Gives back the shortest path.
+///Returns the DFS path to a node.
+///
-///Gives back the shortest path.
+///\warning \c t should be reachable from the root.
-///\pre The \c t should be reachable from the source.
+///
-Path path(Node t)
+///\pre Either \ref run() or \ref start() must be called before
-{
+///using this function.
-return Path(*G, *_pred, t);
+Path path(Node t) const { return Path(*G, *_pred, t); }
-}
+///The distance of a node from the root.
-///The distance of a node from the root(s).
+///Returns the distance of a node from the root.
-///Returns the distance of a node from the root(s).
+///
-///\pre \ref run() must be called before using this function.
+///\warning If node \c v is not reachable from the root, then
-///\warning If node \c v is unreachable from the root(s) then the return
+///the return value of this function is undefined.
-///value of this funcion is undefined.
+///
+///\pre Either \ref run() or \ref start() must be called before
+///using this function.
 int dist(Node v) const { return (*_dist)[v]; }
-///Returns the 'previous arc' of the %DFS tree.
+///Returns the 'previous arc' of the %DFS tree for a node.
-///For a node \c v it returns the 'previous arc'
+///This function returns the 'previous arc' of the %DFS tree for the
-///of the %DFS path,
+///node \c v, i.e. it returns the last arc of a %DFS path from the
-///i.e. it returns the last arc of a %DFS path from the root(s) to \c
+///root to \c v. It is \c INVALID
-///v. It is \ref INVALID
+///if \c v is not reachable from the root(s) or if \c v is a root.
-///if \c v is unreachable from the root(s) or \c v is a root. The
+///
-///%DFS tree used here is equal to the %DFS tree used in
+///The %DFS tree used here is equal to the %DFS tree used in
 ///\ref predNode().
+///
 ///\pre Either \ref run() or \ref start() must be called before using
 ///this function.
 Arc predArc(Node v) const { return (*_pred)[v];}
 ///Returns the 'previous node' of the %DFS tree.
-///For a node \c v it returns the 'previous node'
+///This function returns the 'previous node' of the %DFS
-///of the %DFS tree,
+///tree for the node \c v, i.e. it returns the last but one node
-///i.e. it returns the last but one node from a %DFS path from the
+///from a %DFS path from the root to \c v. It is \c INVALID
-///root(s) to \c v.
+///if \c v is not reachable from the root(s) or if \c v is a root.
-///It is INVALID if \c v is unreachable from the root(s) or
+///
-///if \c v itself a root.
+///The %DFS tree used here is equal to the %DFS tree used in
-///The %DFS tree used here is equal to the %DFS
+///\ref predArc().
-///tree used in \ref predArc().
+///
 ///\pre Either \ref run() or \ref start() must be called before
 ///using this function.
 Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
 G->source((*_pred)[v]); }
-///Returns a reference to the NodeMap of distances.
+///\brief Returns a const reference to the node map that stores the
+///distances of the nodes.
-///Returns a reference to the NodeMap of distances.
+///
-///\pre Either \ref run() or \ref init() must
+///Returns a const reference to the node map that stores the
-///be called before using this function.
+///distances of the nodes calculated by the algorithm.
+///
+///\pre Either \ref run() or \ref init()
+///must be called before using this function.
 const DistMap &distMap() const { return *_dist;}
-///Returns a reference to the %DFS arc-tree map.
+///\brief Returns a const reference to the node map that stores the
+///predecessor arcs.
-///Returns a reference to the NodeMap of the arcs of the
+///
-///%DFS tree.
+///Returns a const reference to the node map that stores the predecessor
+///arcs, which form the DFS tree.
+///
 ///\pre Either \ref run() or \ref init()
 ///must be called before using this function.
 const PredMap &predMap() const { return *_pred;}
-///Checks if a node is reachable from the root.
+///Checks if a node is reachable from the root(s).
 ///Returns \c true if \c v is reachable from the root(s).
-///\warning The source nodes are inditated as unreachable.
 ///\pre Either \ref run() or \ref start()
 ///must be called before using this function.
-///
+bool reached(Node v) const { return (*_reached)[v]; }
-bool reached(Node v) { return (*_reached)[v]; }
 ///@}
 };
-///Default traits class of Dfs function.
+///Default traits class of dfs() function.
-///Default traits class of Dfs function.
+///Default traits class of dfs() function.
 ///\tparam GR Digraph type.
 template<class GR>
 struct DfsWizardDefaultTraits
 {
-///The digraph type the algorithm runs on.
+///The type of the digraph the algorithm runs on.
 typedef GR Digraph;
-///\brief The type of the map that stores the last
+///\brief The type of the map that stores the predecessor
 ///arcs of the %DFS paths.
 ///
-///The type of the map that stores the last
+///The type of the map that stores the predecessor
 ///arcs of the %DFS paths.
 ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
 ///
-typedef NullMap<typename Digraph::Node,typename GR::Arc> PredMap;
+typedef NullMap<typename Digraph::Node,typename Digraph::Arc> PredMap;
-///Instantiates a PredMap.
+///Instantiates a \ref PredMap.
 ///This function instantiates a \ref PredMap.
-///\param g is the digraph, to which we would like to define the PredMap.
+///\param g is the digraph, to which we would like to define the
+///\ref PredMap.
 ///\todo The digraph alone may be insufficient to initialize
 #ifdef DOXYGEN
-static PredMap *createPredMap(const GR &g)
+static PredMap *createPredMap(const Digraph &g)
 #else
-static PredMap *createPredMap(const GR &)
+static PredMap *createPredMap(const Digraph &)
 #endif
 {
 return new PredMap();
 }
 ///The type of the map that indicates which nodes are processed.
 ///The type of the map that indicates which nodes are processed.
 ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
-///\todo named parameter to set this type, function to read and write.
 typedef NullMap<typename Digraph::Node,bool> ProcessedMap;
-///Instantiates a ProcessedMap.
+///Instantiates a \ref ProcessedMap.
 ///This function instantiates a \ref ProcessedMap.
 ///\param g is the digraph, to which
-///we would like to define the \ref ProcessedMap
+///we would like to define the \ref ProcessedMap.
 #ifdef DOXYGEN
-static ProcessedMap *createProcessedMap(const GR &g)
+static ProcessedMap *createProcessedMap(const Digraph &g)
 #else
-static ProcessedMap *createProcessedMap(const GR &)
+static ProcessedMap *createProcessedMap(const Digraph &)
 #endif
 {
 return new ProcessedMap();
 }
 ///The type of the map that indicates which nodes are reached.
 ///The type of the map that indicates which nodes are reached.
+///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept.
+typedef typename Digraph::template NodeMap<bool> ReachedMap;
+///Instantiates a \ref ReachedMap.
+///This function instantiates a \ref ReachedMap.
+///\param g is the digraph, to which
+///we would like to define the \ref ReachedMap.
+static ReachedMap *createReachedMap(const Digraph &g)
+{
+return new ReachedMap(g);
+}
+///The type of the map that stores the distances of the nodes.
+///The type of the map that stores the distances of the nodes.
 ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
-///\todo named parameter to set this type, function to read and write.
-typedef typename Digraph::template NodeMap<bool> ReachedMap;
-///Instantiates a ReachedMap.
-///This function instantiates a \ref ReachedMap.
-///\param G is the digraph, to which
-///we would like to define the \ref ReachedMap.
-static ReachedMap *createReachedMap(const GR &G)
-{
-return new ReachedMap(G);
-}
-///The type of the map that stores the dists of the nodes.
-///The type of the map that stores the dists of the nodes.
-///It must meet the \ref concepts::WriteMap "WriteMap" concept.
 ///
 typedef NullMap<typename Digraph::Node,int> DistMap;
-///Instantiates a DistMap.
+///Instantiates a \ref DistMap.
 ///This function instantiates a \ref DistMap.
 ///\param g is the digraph, to which we would like to define
 ///the \ref DistMap
 #ifdef DOXYGEN
-static DistMap *createDistMap(const GR &g)
+static DistMap *createDistMap(const Digraph &g)
 #else
-static DistMap *createDistMap(const GR &)
+static DistMap *createDistMap(const Digraph &)
 #endif
 {
 return new DistMap();
 }
 };
-/// Default traits used by \ref DfsWizard
+/// Default traits class used by \ref DfsWizard
 /// To make it easier to use Dfs algorithm
-///we have created a wizard class.
+/// we have created a wizard class.
 /// This \ref DfsWizard class needs default traits,
-///as well as the \ref Dfs class.
+/// as well as the \ref Dfs class.
 /// The \ref DfsWizardBase is a class to be the default traits of the
 /// \ref DfsWizard class.
 template<class GR>
 class DfsWizardBase : public DfsWizardDefaultTraits<GR>
 {
 typedef DfsWizardDefaultTraits<GR> Base;
 protected:
-/// Type of the nodes in the digraph.
+//The type of the nodes in the digraph.
 typedef typename Base::Digraph::Node Node;
-/// Pointer to the underlying digraph.
+//Pointer to the digraph the algorithm runs on.
 void *_g;
-///Pointer to the map of reached nodes.
+//Pointer to the map of reached nodes.
 void *_reached;
-///Pointer to the map of processed nodes.
+//Pointer to the map of processed nodes.
 void *_processed;
-///Pointer to the map of predecessors arcs.
+//Pointer to the map of predecessors arcs.
 void *_pred;
-///Pointer to the map of distances.
+//Pointer to the map of distances.
 void *_dist;
-///Pointer to the source node.
+//Pointer to the source node.
 Node _source;
 public:
 /// Constructor.
 /// This constructor does not require parameters, therefore it initiates
 /// all of the attributes to default values (0, INVALID).
 DfsWizardBase() : _g(0), _reached(0), _processed(0), _pred(0),
 _dist(0), _source(INVALID) {}
 /// Constructor.
 /// This constructor requires some parameters,
 /// listed in the parameters list.
 /// Others are initiated to 0.
-/// \param g is the initial value of  \ref _g
+/// \param g The digraph the algorithm runs on.
-/// \param s is the initial value of  \ref _source
+/// \param s The source node.
 DfsWizardBase(const GR &g, Node s=INVALID) :
 _g(reinterpret_cast<void*>(const_cast<GR*>(&g))),
 _reached(0), _processed(0), _pred(0), _dist(0), _source(s) {}
 };
-/// A class to make the usage of the Dfs algorithm easier
+/// Auxiliary class for the function type interface of DFS algorithm.
-/// This class is created to make it easier to use the Dfs algorithm.
+/// This auxiliary class is created to implement the function type
-/// It uses the functions and features of the plain \ref Dfs,
+/// interface of \ref Dfs algorithm. It uses the functions and features
-/// but it is much simpler to use it.
+/// of the plain \ref Dfs, but it is much simpler to use it.
+/// It should only be used through the \ref dfs() function, which makes
+/// it easier to use the algorithm.
 ///
 /// Simplicity means that the way to change the types defined
 /// in the traits class is based on functions that returns the new class
 /// and not on templatable built-in classes.
 /// When using the plain \ref Dfs
 /// the new class with the modified type comes from
 /// the original class by using the ::
 /// operator. In the case of \ref DfsWizard only
-/// a function have to be called and it will
+/// a function have to be called, and it will
 /// return the needed class.
 ///
-/// It does not have own \ref run method. When its \ref run method is called
+/// It does not have own \ref run() method. When its \ref run() method
-/// it initiates a plain \ref Dfs object, and calls the \ref Dfs::run
+/// is called, it initiates a plain \ref Dfs object, and calls the
-/// method of it.
+/// \ref Dfs::run() method of it.
 template<class TR>
 class DfsWizard : public TR
 {
 typedef TR Base;
-///The type of the underlying digraph.
+///The type of the digraph the algorithm runs on.
 typedef typename TR::Digraph Digraph;
-//\e
 typedef typename Digraph::Node Node;
-//\e
 typedef typename Digraph::NodeIt NodeIt;
-//\e
 typedef typename Digraph::Arc Arc;
-//\e
 typedef typename Digraph::OutArcIt OutArcIt;
-///\brief The type of the map that stores
+///\brief The type of the map that stores the predecessor
-///the reached nodes
+///arcs of the shortest paths.
+typedef typename TR::PredMap PredMap;
+///\brief The type of the map that stores the distances of the nodes.
+typedef typename TR::DistMap DistMap;
+///\brief The type of the map that indicates which nodes are reached.
 typedef typename TR::ReachedMap ReachedMap;
-///\brief The type of the map that stores
+///\brief The type of the map that indicates which nodes are processed.
-///the processed nodes
 typedef typename TR::ProcessedMap ProcessedMap;
-///\brief The type of the map that stores the last
-///arcs of the %DFS paths.
-typedef typename TR::PredMap PredMap;
-///The type of the map that stores the distances of the nodes.
-typedef typename TR::DistMap DistMap;
 public:
 /// Constructor.
 DfsWizard() : TR() {}
 /// Constructor that requires parameters.
 ///Copy constructor
 DfsWizard(const TR &b) : TR(b) {}
 ~DfsWizard() {}
-///Runs Dfs algorithm from a given node.
+///Runs DFS algorithm from a source node.
-///Runs Dfs algorithm from a given node.
+///Runs DFS algorithm from a source node.
-///The node can be given by the \ref source function.
+///The node can be given with the \ref source() function.
 void run()
 {
 if(Base::_source==INVALID) throw UninitializedParameter();
 Dfs<Digraph,TR> alg(*reinterpret_cast<const Digraph*>(Base::_g));
 if(Base::_reached)
 if(Base::_dist)
 alg.distMap(*reinterpret_cast<DistMap*>(Base::_dist));
 alg.run(Base::_source);
 }
-///Runs Dfs algorithm from the given node.
+///Runs DFS algorithm from the given node.
-///Runs Dfs algorithm from the given node.
+///Runs DFS algorithm from the given node.
 ///\param s is the given source.
 void run(Node s)
 {
 Base::_source=s;
 run();
+}
+/// Sets the source node, from which the Dfs algorithm runs.
+/// Sets the source node, from which the Dfs algorithm runs.
+/// \param s is the source node.
+DfsWizard<TR> &source(Node s)
+{
+Base::_source=s;
+return *this;
 }
 template<class T>
 struct DefPredMapBase : public Base {
 typedef T PredMap;
 static PredMap *createPredMap(const Digraph &) { return 0; };
 DefPredMapBase(const TR &b) : TR(b) {}
 };
 ///\brief \ref named-templ-param "Named parameter"
-///function for setting PredMap type
+///for setting \ref PredMap object.
 ///
-/// \ref named-templ-param "Named parameter"
+///\ref named-templ-param "Named parameter"
-///function for setting PredMap type
+///for setting \ref PredMap object.
-///
 template<class T>
 DfsWizard<DefPredMapBase<T> > predMap(const T &t)
 {
 Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t));
 return DfsWizard<DefPredMapBase<T> >(*this);
 }
 template<class T>
 struct DefReachedMapBase : public Base {
 typedef T ReachedMap;
 static ReachedMap *createReachedMap(const Digraph &) { return 0; };
 DefReachedMapBase(const TR &b) : TR(b) {}
 };
 ///\brief \ref named-templ-param "Named parameter"
-///function for setting ReachedMap
+///for setting \ref ReachedMap object.
 ///
 /// \ref named-templ-param "Named parameter"
-///function for setting ReachedMap
+///for setting \ref ReachedMap object.
-///
 template<class T>
 DfsWizard<DefReachedMapBase<T> > reachedMap(const T &t)
 {
 Base::_reached=reinterpret_cast<void*>(const_cast<T*>(&t));
 return DfsWizard<DefReachedMapBase<T> >(*this);
 }
 template<class T>
 struct DefProcessedMapBase : public Base {
 typedef T ProcessedMap;
 static ProcessedMap *createProcessedMap(const Digraph &) { return 0; };
 DefProcessedMapBase(const TR &b) : TR(b) {}
 };
 ///\brief \ref named-templ-param "Named parameter"
-///function for setting ProcessedMap
+///for setting \ref ProcessedMap object.
 ///
 /// \ref named-templ-param "Named parameter"
-///function for setting ProcessedMap
+///for setting \ref ProcessedMap object.
-///
 template<class T>
 DfsWizard<DefProcessedMapBase<T> > processedMap(const T &t)
 {
 Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t));
 return DfsWizard<DefProcessedMapBase<T> >(*this);
 struct DefDistMapBase : public Base {
 typedef T DistMap;
 static DistMap *createDistMap(const Digraph &) { return 0; };
 DefDistMapBase(const TR &b) : TR(b) {}
 };
 ///\brief \ref named-templ-param "Named parameter"
-///function for setting DistMap type
+///for setting \ref DistMap object.
 ///
-/// \ref named-templ-param "Named parameter"
+///\ref named-templ-param "Named parameter"
-///function for setting DistMap type
+///for setting \ref DistMap object.
-///
 template<class T>
 DfsWizard<DefDistMapBase<T> > distMap(const T &t)
 {
 Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t));
 return DfsWizard<DefDistMapBase<T> >(*this);
-}
-/// Sets the source node, from which the Dfs algorithm runs.
-/// Sets the source node, from which the Dfs algorithm runs.
-/// \param s is the source node.
-DfsWizard<TR> &source(Node s)
-{
-Base::_source=s;
-return *this;
 }
 };
 ///Function type interface for Dfs algorithm.
 {
 return DfsWizard<DfsWizardBase<GR> >(g,s);
 }
 #ifdef DOXYGEN
-/// \brief Visitor class for dfs.
+/// \brief Visitor class for DFS.
 ///
-/// It gives a simple interface for a functional interface for dfs
+/// This class defines the interface of the DfsVisit events, and
-/// traversal. The traversal on a linear data structure.
+/// it could be the base of a real visitor class.
 template <typename _Digraph>
 struct DfsVisitor {
 typedef _Digraph Digraph;
 typedef typename Digraph::Arc Arc;
 typedef typename Digraph::Node Node;
-/// \brief Called when the arc reach a node.
+/// \brief Called for the source node of the DFS.
 ///
-/// It is called when the dfs find an arc which target is not
+/// This function is called for the source node of the DFS.
-/// reached yet.
+void start(const Node& node) {}
+/// \brief Called when the source node is leaved.
+///
+/// This function is called when the source node is leaved.
+void stop(const Node& node) {}
+/// \brief Called when a node is reached first time.
+///
+/// This function is called when a node is reached first time.
+void reach(const Node& node) {}
+/// \brief Called when an arc reaches a new node.
+///
+/// This function is called when the DFS finds an arc whose target node
+/// is not reached yet.
 void discover(const Arc& arc) {}
-/// \brief Called when the node reached first time.
+/// \brief Called when an arc is examined but its target node is
-///
-/// It is Called when the node reached first time.
-void reach(const Node& node) {}
-/// \brief Called when we step back on an arc.
-///
-/// It is called when the dfs should step back on the arc.
-void backtrack(const Arc& arc) {}
-/// \brief Called when we step back from the node.
-///
-/// It is called when we step back from the node.
-void leave(const Node& node) {}
-/// \brief Called when the arc examined but target of the arc
 /// already discovered.
 ///
-/// It called when the arc examined but the target of the arc
+/// This function is called when an arc is examined but its target node is
 /// already discovered.
 void examine(const Arc& arc) {}
-/// \brief Called for the source node of the dfs.
+/// \brief Called when the DFS steps back from a node.
 ///
-/// It is called for the source node of the dfs.
+/// This function is called when the DFS steps back from a node.
-void start(const Node& node) {}
+void leave(const Node& node) {}
-/// \brief Called when we leave the source node of the dfs.
+/// \brief Called when the DFS steps back on an arc.
 ///
-/// It is called when we leave the source node of the dfs.
+/// This function is called when the DFS steps back on an arc.
-void stop(const Node& node) {}
+void backtrack(const Arc& arc) {}
 };
 #else
 template <typename _Digraph>
 struct DfsVisitor {
 typedef _Digraph Digraph;
 typedef typename Digraph::Arc Arc;
 typedef typename Digraph::Node Node;
-void discover(const Arc&) {}
-void reach(const Node&) {}
-void backtrack(const Arc&) {}
-void leave(const Node&) {}
-void examine(const Arc&) {}
 void start(const Node&) {}
 void stop(const Node&) {}
+void reach(const Node&) {}
+void discover(const Arc&) {}
+void examine(const Arc&) {}
+void leave(const Node&) {}
+void backtrack(const Arc&) {}
 template <typename _Visitor>
 struct Constraints {
 void constraints() {
 Arc arc;
 Node node;
-visitor.discover(arc);
-visitor.reach(node);
-visitor.backtrack(arc);
-visitor.leave(node);
-visitor.examine(arc);
 visitor.start(node);
 visitor.stop(arc);
+visitor.reach(node);
+visitor.discover(arc);
+visitor.examine(arc);
+visitor.leave(node);
+visitor.backtrack(arc);
 }
 _Visitor& visitor;
 };
 };
 #endif
 /// \brief Default traits class of DfsVisit class.
 ///
 /// Default traits class of DfsVisit class.
-/// \tparam _Digraph Digraph type.
+/// \tparam _Digraph The type of the digraph the algorithm runs on.
 template<class _Digraph>
 struct DfsVisitDefaultTraits {
-/// \brief The digraph type the algorithm runs on.
+/// \brief The type of the digraph the algorithm runs on.
 typedef _Digraph Digraph;
 /// \brief The type of the map that indicates which nodes are reached.
 ///
 /// The type of the map that indicates which nodes are reached.
-/// It must meet the \ref concepts::WriteMap "WriteMap" concept.
+/// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept.
-/// \todo named parameter to set this type, function to read and write.
 typedef typename Digraph::template NodeMap<bool> ReachedMap;
-/// \brief Instantiates a ReachedMap.
+/// \brief Instantiates a \ref ReachedMap.
 ///
 /// This function instantiates a \ref ReachedMap.
 /// \param digraph is the digraph, to which
 /// we would like to define the \ref ReachedMap.
 static ReachedMap *createReachedMap(const Digraph &digraph) {
 return new ReachedMap(digraph);
 }
 };
-/// %DFS Visit algorithm class.
 /// \ingroup search
+///
+/// \brief %DFS algorithm class with visitor interface.
+///
 /// This class provides an efficient implementation of the %DFS algorithm
 /// with visitor interface.
 ///
 /// The %DfsVisit class provides an alternative interface to the Dfs
 /// class. It works with callback mechanism, the DfsVisit object calls
-/// on every dfs event the \c Visitor class member functions.
+/// the member functions of the \c Visitor class on every DFS event.
 ///
-/// \tparam _Digraph The digraph type the algorithm runs on.
+/// \tparam _Digraph The type of the digraph the algorithm runs on.
 /// The default value is
-/// \ref ListDigraph. The value of _Digraph is not used directly by Dfs, it
+/// \ref ListDigraph. The value of _Digraph is not used directly by
-/// is only passed to \ref DfsDefaultTraits.
+/// \ref DfsVisit, it is only passed to \ref DfsVisitDefaultTraits.
-/// \tparam _Visitor The Visitor object for the algorithm. The
+/// \tparam _Visitor The Visitor type that is used by the algorithm.
-/// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty Visitor which
+/// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty visitor, which
-/// does not observe the Dfs events. If you want to observe the dfs
+/// does not observe the DFS events. If you want to observe the DFS
-/// events you should implement your own Visitor class.
+/// events, you should implement your own visitor class.
 /// \tparam _Traits Traits class to set various data types used by the
 /// algorithm. The default traits class is
 /// \ref DfsVisitDefaultTraits "DfsVisitDefaultTraits<_Digraph>".
 /// See \ref DfsVisitDefaultTraits for the documentation of
-/// a Dfs visit traits class.
+/// a DFS visit traits class.
-///
-/// \author Jacint Szabo, Alpar Juttner and Balazs Dezso
 #ifdef DOXYGEN
 template <typename _Digraph, typename _Visitor, typename _Traits>
 #else
 template <typename _Digraph = ListDigraph,
 typename _Visitor = DfsVisitor<_Digraph>,
 public:
 /// \brief \ref Exception for uninitialized parameters.
 ///
 /// This error represents problems in the initialization
-/// of the parameters of the algorithms.
+/// of the parameters of the algorithm.
 class UninitializedParameter : public lemon::UninitializedParameter {
 public:
 virtual const char* what() const throw()
 {
 return "lemon::DfsVisit::UninitializedParameter";
 }
 };
+///The traits class.
 typedef _Traits Traits;
+///The type of the digraph the algorithm runs on.
 typedef typename Traits::Digraph Digraph;
+///The visitor type used by the algorithm.
 typedef _Visitor Visitor;
-///The type of the map indicating which nodes are reached.
+///The type of the map that indicates which nodes are reached.
 typedef typename Traits::ReachedMap ReachedMap;
 private:
 typedef typename Digraph::Node Node;
 typedef typename Digraph::NodeIt NodeIt;
 typedef typename Digraph::Arc Arc;
 typedef typename Digraph::OutArcIt OutArcIt;
-/// Pointer to the underlying digraph.
+//Pointer to the underlying digraph.
 const Digraph *_digraph;
-/// Pointer to the visitor object.
+//Pointer to the visitor object.
 Visitor *_visitor;
-///Pointer to the map of reached status of the nodes.
+//Pointer to the map of reached status of the nodes.
 ReachedMap *_reached;
-///Indicates if \ref _reached is locally allocated (\c true) or not.
+//Indicates if _reached is locally allocated (true) or not.
 bool local_reached;
 std::vector<typename Digraph::Arc> _stack;
 int _stack_head;
-/// \brief Creates the maps if necessary.
+///Creates the maps if necessary.
-///
+///\todo Better memory allocation (instead of new).
-/// Creates the maps if necessary.
 void create_maps() {
 if(!_reached) {
 local_reached = true;
 _reached = Traits::createReachedMap(*_digraph);
 }
 static ReachedMap *createReachedMap(const Digraph &digraph) {
 throw UninitializedParameter();
 }
 };
 /// \brief \ref named-templ-param "Named parameter" for setting
-/// ReachedMap type
+/// ReachedMap type.
 ///
-/// \ref named-templ-param "Named parameter" for setting ReachedMap type
+/// \ref named-templ-param "Named parameter" for setting ReachedMap type.
 template <class T>
 struct DefReachedMap : public DfsVisit< Digraph, Visitor,
 DefReachedMapTraits<T> > {
 typedef DfsVisit< Digraph, Visitor, DefReachedMapTraits<T> > Create;
 };
 /// \brief Constructor.
 ///
 /// Constructor.
 ///
-/// \param digraph the digraph the algorithm will run on.
+/// \param digraph The digraph the algorithm runs on.
-/// \param visitor The visitor of the algorithm.
+/// \param visitor The visitor object of the algorithm.
-///
 DfsVisit(const Digraph& digraph, Visitor& visitor)
 : _digraph(&digraph), _visitor(&visitor),
 _reached(0), local_reached(false) {}
 /// \brief Destructor.
-///
-/// Destructor.
 ~DfsVisit() {
 if(local_reached) delete _reached;
 }
-/// \brief Sets the map indicating if a node is reached.
+/// \brief Sets the map that indicates which nodes are reached.
 ///
-/// Sets the map indicating if a node is reached.
+/// Sets the map that indicates which nodes are reached.
 /// If you don't use this function before calling \ref run(),
-/// it will allocate one. The destuctor deallocates this
+/// it will allocate one. The destructor deallocates this
 /// automatically allocated map, of course.
 /// \return <tt> (*this) </tt>
 DfsVisit &reachedMap(ReachedMap &m) {
 if(local_reached) {
 delete _reached;
 _reached = &m;
 return *this;
 }
 public:
 /// \name Execution control
 /// The simplest way to execute the algorithm is to use
-/// one of the member functions called \c run(...).
+/// one of the member functions called \ref lemon::DfsVisit::run()
+/// "run()".
 /// \n
-/// If you need more control on the execution,
+/// If you need more control on the execution, first you must call
-/// first you must call \ref init(), then you can adda source node
+/// \ref lemon::DfsVisit::init() "init()", then you can add several
-/// with \ref addSource().
+/// source nodes with \ref lemon::DfsVisit::addSource() "addSource()".
-/// Finally \ref start() will perform the actual path
+/// Finally \ref lemon::DfsVisit::start() "start()" will perform the
-/// computation.
+/// actual path computation.
 /// @{
 /// \brief Initializes the internal data structures.
 ///
 /// Initializes the internal data structures.
-///
 void init() {
 create_maps();
 _stack.resize(countNodes(*_digraph));
 _stack_head = -1;
 for (NodeIt u(*_digraph) ; u != INVALID ; ++u) {
 _reached->set(u, false);
 }
 }
-/// \brief Adds a new source node.
+///Adds a new source node.
-///
-/// Adds a new source node to the set of nodes to be processed.
+///Adds a new source node to the set of nodes to be processed.
-void addSource(Node s) {
+///
+///\pre The stack must be empty. (Otherwise the algorithm gives
+///false results.)
+///
+///\warning Distances will be wrong (or at least strange) in case of
+///multiple sources.
+void addSource(Node s)
+{
+LEMON_DEBUG(emptyQueue(), "The stack is not empty.");
 if(!(*_reached)[s]) {
 _reached->set(s,true);
 _visitor->start(s);
 _visitor->reach(s);
 Arc e;
 ///
 /// Processes the next arc.
 ///
 /// \return The processed arc.
 ///
-/// \pre The stack must not be empty!
+/// \pre The stack must not be empty.
 Arc processNextArc() {
 Arc e = _stack[_stack_head];
 Node m = _digraph->target(e);
 if(!(*_reached)[m]) {
 _visitor->discover(e);
 ///
 /// Next arc to be processed.
 ///
 /// \return The next arc to be processed or INVALID if the stack is
 /// empty.
-Arc nextArc() {
+Arc nextArc() const {
 return _stack_head >= 0 ? _stack[_stack_head] : INVALID;
 }
 /// \brief Returns \c false if there are nodes
-/// to be processed in the queue
+/// to be processed.
 ///
 /// Returns \c false if there are nodes
-/// to be processed in the queue
+/// to be processed in the queue (stack).
-bool emptyQueue() { return _stack_head < 0; }
+bool emptyQueue() const { return _stack_head < 0; }
 /// \brief Returns the number of the nodes to be processed.
 ///
-/// Returns the number of the nodes to be processed in the queue.
+/// Returns the number of the nodes to be processed in the queue (stack).
-int queueSize() { return _stack_head + 1; }
+int queueSize() const { return _stack_head + 1; }
 /// \brief Executes the algorithm.
 ///
 /// Executes the algorithm.
 ///
-/// \pre init() must be called and at least one node should be added
+/// This method runs the %DFS algorithm from the root node
-/// with addSource() before using this function.
+/// in order to compute the %DFS path to each node.
+///
+/// The algorithm computes
+/// - the %DFS tree,
+/// - the distance of each node from the root in the %DFS tree.
+///
+/// \pre init() must be called and a root node should be
+/// added with addSource() before using this function.
+///
+/// \note <tt>d.start()</tt> is just a shortcut of the following code.
+/// \code
+///   while ( !d.emptyQueue() ) {
+///     d.processNextArc();
+///   }
+/// \endcode
 void start() {
 while ( !emptyQueue() ) processNextArc();
 }
-/// \brief Executes the algorithm until \c dest is reached.
+/// \brief Executes the algorithm until the given target node is reached.
 ///
-/// Executes the algorithm until \c dest is reached.
+/// Executes the algorithm until the given target node is reached.
 ///
-/// \pre init() must be called and at least one node should be added
+/// This method runs the %DFS algorithm from the root node
+/// in order to compute the DFS path to \c dest.
+///
+/// The algorithm computes
+/// - the %DFS path to \c dest,
+/// - the distance of \c dest from the root in the %DFS tree.
+///
+/// \pre init() must be called and a root node should be added
 /// with addSource() before using this function.
 void start(Node dest) {
 while ( !emptyQueue() && _digraph->target(_stack[_stack_head]) != dest )
 processNextArc();
 }
 /// \brief Executes the algorithm until a condition is met.
 ///
 /// Executes the algorithm until a condition is met.
 ///
-/// \pre init() must be called and at least one node should be added
+/// This method runs the %DFS algorithm from the root node
+/// until an arc \c a with <tt>am[a]</tt> true is found.
+///
+/// \param am A \c bool (or convertible) arc map. The algorithm
+/// will stop when it reaches an arc \c a with <tt>am[a]</tt> true.
+///
+/// \return The reached arc \c a with <tt>am[a]</tt> true or
+/// \c INVALID if no such arc was found.
+///
+/// \pre init() must be called and a root node should be added
 /// with addSource() before using this function.
 ///
-/// \param em must be a bool (or convertible) arc map. The algorithm
+/// \warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map,
-/// will stop when it reaches an arc \c e with <tt>em[e]</tt> true.
-///
-///\return The reached arc \c e with <tt>em[e]</tt> true or
-///\c INVALID if no such arc was found.
-///
-/// \warning Contrary to \ref Bfs and \ref Dijkstra, \c em is an arc map,
 /// not a node map.
-template <typename EM>
+template <typename AM>
-Arc start(const EM &em) {
+Arc start(const AM &am) {
-while ( !emptyQueue() && !em[_stack[_stack_head]] )
+while ( !emptyQueue() && !am[_stack[_stack_head]] )
 processNextArc();
 return emptyQueue() ? INVALID : _stack[_stack_head];
 }
-/// \brief Runs %DFSVisit algorithm from node \c s.
+/// \brief Runs the algorithm from the given node.
 ///
-/// This method runs the %DFS algorithm from a root node \c s.
+/// This method runs the %DFS algorithm from node \c s.
-/// \note d.run(s) is just a shortcut of the following code.
+/// in order to compute the DFS path to each node.
+///
+/// The algorithm computes
+/// - the %DFS tree,
+/// - the distance of each node from the root in the %DFS tree.
+///
+/// \note <tt>d.run(s)</tt> is just a shortcut of the following code.
 ///\code
 ///   d.init();
 ///   d.addSource(s);
 ///   d.start();
 ///\endcode
 init();
 addSource(s);
 start();
 }
-/// \brief Runs %DFSVisit algorithm to visit all nodes in the digraph.
+/// \brief Finds the %DFS path between \c s and \c t.
+/// This method runs the %DFS algorithm from node \c s
+/// in order to compute the DFS path to \c t.
+///
+/// \return The length of the <tt>s</tt>--<tt>t</tt> DFS path,
+/// if \c t is reachable form \c s, \c 0 otherwise.
+///
+/// \note Apart from the return value, <tt>d.run(s,t)</tt> is
+/// just a shortcut of the following code.
+///\code
+///   d.init();
+///   d.addSource(s);
+///   d.start(t);
+///\endcode
+int run(Node s,Node t) {
+init();
+addSource(s);
+start(t);
+return reached(t)?_stack_head+1:0;
+}
+/// \brief Runs the algorithm to visit all nodes in the digraph.
 /// This method runs the %DFS algorithm in order to
-/// compute the %DFS path to each node. The algorithm computes
+/// compute the %DFS path to each node.
-/// - The %DFS tree.
+///
-/// - The distance of each node from the root in the %DFS tree.
+/// The algorithm computes
-///
+/// - the %DFS tree,
-///\note d.run() is just a shortcut of the following code.
+/// - the distance of each node from the root in the %DFS tree.
+///
+/// \note <tt>d.run()</tt> is just a shortcut of the following code.
 ///\code
-///  d.init();
+///   d.init();
-///  for (NodeIt it(digraph); it != INVALID; ++it) {
+///   for (NodeIt n(digraph); n != INVALID; ++n) {
-///    if (!d.reached(it)) {
+///     if (!d.reached(n)) {
-///      d.addSource(it);
+///       d.addSource(n);
-///      d.start();
+///       d.start();
-///    }
+///     }
-///  }
+///   }
 ///\endcode
 void run() {
 init();
 for (NodeIt it(*_digraph); it != INVALID; ++it) {
 if (!reached(it)) {
 addSource(it);
 start();
 }
 }
 }
 ///@}
 /// \name Query Functions
 /// The result of the %DFS algorithm can be obtained using these
 /// functions.\n
-/// Before the use of these functions,
+/// Either \ref lemon::DfsVisit::run() "run()" or
-/// either run() or start() must be called.
+/// \ref lemon::DfsVisit::start() "start()" must be called before
+/// using them.
 ///@{
-/// \brief Checks if a node is reachable from the root.
+/// \brief Checks if a node is reachable from the root(s).
 ///
 /// Returns \c true if \c v is reachable from the root(s).
-/// \warning The source nodes are inditated as unreachable.
 /// \pre Either \ref run() or \ref start()
 /// must be called before using this function.
-///
 bool reached(Node v) { return (*_reached)[v]; }
 ///@}
 };
 } //END OF NAMESPACE LEMON
 #endif

changeset 248	8fada33fc60a
parent 220	a5d8c039f218
parent 244	c30731a37f91
child 252	66644b9cd9eb
child 257	8d76a7bf9961