diff --git a/lemon/dfs.h b/lemon/dfs.h --- a/lemon/dfs.h +++ b/lemon/dfs.h @@ -21,19 +21,17 @@ ///\ingroup search ///\file -///\brief Dfs algorithm. +///\brief DFS algorithm. #include #include #include #include +#include #include -#include - namespace lemon { - ///Default traits class of Dfs class. ///Default traits class of Dfs class. @@ -41,74 +39,75 @@ template 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 PredMap; - ///Instantiates a PredMap. + typedef typename Digraph::template NodeMap 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 - 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 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::WriteMap "WriteMap" concept. - ///\todo named parameter to set this type, function to read and write. + ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. typedef typename Digraph::template NodeMap ReachedMap; - ///Instantiates a ReachedMap. + ///Instantiates a \ref ReachedMap. ///This function instantiates a \ref ReachedMap. - ///\param G is the digraph, to which + ///\param g is the digraph, to which ///we would like to define the \ref ReachedMap. - static ReachedMap *createReachedMap(const GR &G) + static ReachedMap *createReachedMap(const Digraph &g) { - return new ReachedMap(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. + ///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. - /// typedef typename Digraph::template NodeMap 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 - static DistMap *createDistMap(const GR &G) + ///\param g is the digraph, to which we would like to define the + ///\ref DistMap. + static DistMap *createDistMap(const Digraph &g) { - return new DistMap(G); + return new DistMap(g); } }; @@ -117,9 +116,13 @@ ///\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 - ///\ref ListDigraph. The value of GR is not used directly by Dfs, it - ///is only passed to \ref DfsDefaultTraits. + ///There is also a \ref dfs() "function type interface" for the DFS + ///algorithm, which is convenient in the simplier cases and it can be + ///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". @@ -134,12 +137,10 @@ #endif class Dfs { public: - /** - * \brief \ref Exception for uninitialized parameters. - * - * This error represents problems in the initialization - * of the parameters of the algorithms. - */ + ///\ref Exception for uninitialized parameters. + + ///This error represents problems in the initialization of the + ///parameters of the algorithm. class UninitializedParameter : public lemon::UninitializedParameter { public: virtual const char* what() const throw() { @@ -147,52 +148,54 @@ } }; + ///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 Path; + + ///The traits class. typedef TR Traits; - ///The type of the underlying digraph. - typedef typename TR::Digraph Digraph; - ///\e + + private: + 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 - ///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. + //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 _stack; int _stack_head; ///Creates the maps if necessary. - ///\todo Better memory allocation (instead of new). void create_maps() { @@ -229,22 +232,21 @@ template 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 struct DefPredMap : public Dfs > { typedef Dfs > Create; }; - template struct DefDistMapTraits : public Traits { typedef T DistMap; @@ -254,12 +256,12 @@ } }; ///\brief \ref named-templ-param "Named parameter" for setting - ///DistMap type + ///\ref DistMap type. /// - ///\ref named-templ-param "Named parameter" for setting DistMap - ///type + ///\ref named-templ-param "Named parameter" for setting + ///\ref DistMap type. template - struct DefDistMap { + struct DefDistMap : public Dfs< Digraph, DefDistMapTraits > { typedef Dfs > Create; }; @@ -272,10 +274,10 @@ } }; ///\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 struct DefReachedMap : public Dfs< Digraph, DefReachedMapTraits > { typedef Dfs< Digraph, DefReachedMapTraits > Create; @@ -290,10 +292,10 @@ } }; ///\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 struct DefProcessedMap : public Dfs< Digraph, DefProcessedMapTraits > { typedef Dfs< Digraph, DefProcessedMapTraits > Create; @@ -301,19 +303,19 @@ struct DefDigraphProcessedMapTraits : public Traits { typedef typename Digraph::template NodeMap 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" - ///for setting the ProcessedMap type to be Digraph::NodeMap. + ///\brief \ref named-templ-param "Named parameter" for setting + ///\ref ProcessedMap type to be Digraph::NodeMap. /// - ///\ref named-templ-param "Named parameter" - ///for setting the ProcessedMap type to be Digraph::NodeMap. - ///If you don't set it explicitely, it will be automatically allocated. + ///\ref named-templ-param "Named parameter" for setting + ///\ref ProcessedMap type to be Digraph::NodeMap. + ///If you don't set it explicitly, it will be automatically allocated. template - class DefProcessedMapToBeDefaultMap : + struct DefProcessedMapToBeDefaultMap : public Dfs< Digraph, DefDigraphProcessedMapTraits> { typedef Dfs< Digraph, DefDigraphProcessedMapTraits> Create; }; @@ -324,10 +326,10 @@ ///Constructor. - ///\param _G the digraph the algorithm will run on. - /// - Dfs(const Digraph& _G) : - G(&_G), + ///Constructor. + ///\param g The digraph the algorithm runs on. + Dfs(const Digraph &g) : + G(&g), _pred(NULL), local_pred(false), _dist(NULL), local_dist(false), _reached(NULL), local_reached(false), @@ -343,11 +345,11 @@ 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 (*this) Dfs &predMap(PredMap &m) @@ -360,11 +362,46 @@ 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 (*this) + 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 (*this) + 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 (*this) Dfs &distMap(DistMap &m) @@ -377,50 +414,17 @@ return *this; } - ///Sets the map indicating if a node is reached. + public: - ///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 (*this) - 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 (*this) - 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, - ///first you must call \ref init(), then you can add a source node - ///with \ref addSource(). - ///Finally \ref start() will perform the actual path - ///computation. + ///If you need more control on the execution, first you must call + ///\ref lemon::Dfs::init() "init()", then you can add a source node + ///with \ref lemon::Dfs::addSource() "addSource()". + ///Finally \ref lemon::Dfs::start() "start()" will perform the + ///actual path computation. ///@{ @@ -435,7 +439,6 @@ _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); } @@ -445,10 +448,14 @@ ///Adds a new source node to the set of nodes to be processed. /// - ///\warning dists are wrong (or at least strange) - ///in case of multiple sources. + ///\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); @@ -471,7 +478,7 @@ /// ///\return The processed arc. /// - ///\pre The stack must not be empty! + ///\pre The stack must not be empty. Arc processNextArc() { Node m; @@ -497,61 +504,68 @@ } 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 - /// empty. - OutArcIt nextArc() + ///\return The next arc to be processed or \c INVALID if the stack + ///is empty. + 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 - bool emptyQueue() { return _stack_head<0; } + ///to be processed in the queue (stack). + 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. - int queueSize() { return _stack_head+1; } + ///Returns the number of the nodes to be processed in the queue (stack). + 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 - ///with addSource() before using this function. + ///This method runs the %DFS algorithm from the root node + ///in order to compute the DFS path to each node. /// - ///This method runs the %DFS algorithm from the root node(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(s) in the %DFS tree. + /// 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 d.start() 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 - ///with addSource() before using this function. + ///This method runs the %DFS algorithm from the root node + ///in order to compute the DFS path to \c dest. /// - ///This method runs the %DFS algorithm from the root node(s) - ///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(s) in the %DFS tree. + ///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() && G->target(_stack[_stack_head])!=dest ) @@ -562,39 +576,86 @@ ///Executes the algorithm until a condition is met. /// - ///\pre init() must be called and at least one node should be added - ///with addSource() before using this function. + ///This method runs the %DFS algorithm from the root node + ///until an arc \c a with am[a] true is found. /// - ///\param em must be a bool (or convertible) arc map. The algorithm - ///will stop when it reaches an arc \c e with em[e] true. + ///\param am A \c bool (or convertible) arc map. The algorithm + ///will stop when it reaches an arc \c a with am[a] true. /// - ///\return The reached arc \c e with em[e] true or + ///\return The reached arc \c a with am[a] 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 - Arc start(const EM &em) + template + 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 - ///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. + ///This method runs the %DFS algorithm from node \c s + ///in order to compute the DFS path to each node. /// - ///\note d.run() is just a shortcut of the following code. + ///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(); - /// for (NodeIt it(digraph); it != INVALID; ++it) { - /// if (!d.reached(it)) { - /// d.addSource(it); + /// d.addSource(s); + /// d.start(); + ///\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 s--t DFS path, + ///if \c t is reachable form \c s, \c 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; + } + + ///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 d.run() 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(); /// } /// } @@ -609,157 +670,124 @@ } } - ///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 run() or start() must be called. + ///Either \ref lemon::Dfs::run() "run()" or \ref lemon::Dfs::start() + ///"start()" must be called before using them. ///@{ - typedef PredMapPath Path; + ///The DFS path to a node. - ///Gives back the shortest path. + ///Returns the DFS path to a node. + /// + ///\warning \c t should be reachable from the root. + /// + ///\pre Either \ref run() or \ref start() must be called before + ///using this function. + Path path(Node t) const { return Path(*G, *_pred, t); } - ///Gives back the shortest path. - ///\pre The \c t should be reachable from the source. - Path path(Node t) - { - 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(s). - ///\pre \ref run() must be called before using this function. - ///\warning If node \c v is unreachable from the root(s) then the return - ///value of this funcion is undefined. + ///Returns the distance of a node from the root. + /// + ///\warning If node \c v is not reachable from the root, then + ///the return value of this function 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' - ///of the %DFS path, - ///i.e. it returns the last arc of a %DFS path from the root(s) to \c - ///v. It is \ref INVALID - ///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 + ///This function returns the 'previous arc' of the %DFS tree for the + ///node \c v, i.e. it returns the last arc of a %DFS path from the + ///root to \c v. It is \c INVALID + ///if \c v is not reachable from the root(s) or if \c v is a root. + /// + ///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' - ///of the %DFS tree, - ///i.e. it returns the last but one node from a %DFS path from the - ///root(s) to \c v. - ///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 \ref predArc(). + ///This function returns the 'previous node' of the %DFS + ///tree for the node \c v, i.e. it returns the last but one node + ///from a %DFS path from the root to \c v. It is \c INVALID + ///if \c v is not reachable from the root(s) or if \c v is a root. + /// + ///The %DFS tree used here is equal to the %DFS 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. - - ///Returns a reference to the NodeMap of distances. - ///\pre Either \ref run() or \ref init() must - ///be called before using this function. + ///\brief Returns a const reference to the node map that stores the + ///distances of the nodes. + /// + ///Returns a const reference to the node map that stores the + ///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. - - ///Returns a reference to the NodeMap of the arcs of the - ///%DFS tree. + ///\brief Returns a const reference to the node map that stores the + ///predecessor arcs. + /// + ///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) { return (*_reached)[v]; } + bool reached(Node v) const { 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 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 PredMap; - ///Instantiates a PredMap. + typedef NullMap 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(); @@ -769,63 +797,63 @@ ///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 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::WriteMap "WriteMap" concept. - ///\todo named parameter to set this type, function to read and write. + ///It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. typedef typename Digraph::template NodeMap ReachedMap; - ///Instantiates a ReachedMap. + ///Instantiates a \ref ReachedMap. ///This function instantiates a \ref ReachedMap. - ///\param G is the digraph, to which + ///\param g is the digraph, to which ///we would like to define the \ref ReachedMap. - static ReachedMap *createReachedMap(const GR &G) + static ReachedMap *createReachedMap(const Digraph &g) { - return new ReachedMap(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. + ///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. /// typedef NullMap 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 @@ -834,20 +862,20 @@ typedef DfsWizardDefaultTraits 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: @@ -856,26 +884,28 @@ /// 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) {} + _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 s is the initial value of \ref _source + /// \param g The digraph the algorithm runs on. + /// \param s The source node. DfsWizardBase(const GR &g, Node s=INVALID) : _g(reinterpret_cast(const_cast(&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. - /// It uses the functions and features of the plain \ref Dfs, - /// but it is much simpler to use it. + /// This auxiliary class is created to implement the function type + /// interface of \ref Dfs algorithm. It uses the functions and features + /// 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 @@ -884,41 +914,37 @@ /// 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 initiates a plain \ref Dfs object, and calls the \ref Dfs::run - /// method of it. + /// It does not have own \ref run() method. When its \ref run() method + /// is called, it initiates a plain \ref Dfs object, and calls the + /// \ref Dfs::run() method of it. template 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 - ///the reached nodes + ///\brief The type of the map that stores the predecessor + ///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 - ///the processed nodes + ///\brief The type of the map that indicates which nodes are processed. 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() {} @@ -934,10 +960,10 @@ ~DfsWizard() {} - ///Runs Dfs algorithm from a given node. + ///Runs DFS algorithm from a source node. - ///Runs Dfs algorithm from a given node. - ///The node can be given by the \ref source function. + ///Runs DFS algorithm from a source node. + ///The node can be given with the \ref source() function. void run() { if(Base::_source==INVALID) throw UninitializedParameter(); @@ -953,9 +979,9 @@ 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) { @@ -963,19 +989,27 @@ 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 &source(Node s) + { + Base::_source=s; + return *this; + } + template 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" - ///function for setting PredMap type - /// + ///\ref named-templ-param "Named parameter" + ///for setting \ref PredMap object. template DfsWizard > predMap(const T &t) { @@ -983,20 +1017,17 @@ return DfsWizard >(*this); } - template 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 DfsWizard > reachedMap(const T &t) { @@ -1004,20 +1035,17 @@ return DfsWizard >(*this); } - template 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 DfsWizard > processedMap(const T &t) { @@ -1031,13 +1059,11 @@ 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" - ///function for setting DistMap type - /// + ///\ref named-templ-param "Named parameter" + ///for setting \ref DistMap object. template DfsWizard > distMap(const T &t) { @@ -1045,16 +1071,6 @@ return DfsWizard >(*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 &source(Node s) - { - Base::_source=s; - return *this; - } - }; ///Function type interface for Dfs algorithm. @@ -1082,47 +1098,46 @@ } #ifdef DOXYGEN - /// \brief Visitor class for dfs. + /// \brief Visitor class for DFS. /// - /// It gives a simple interface for a functional interface for dfs - /// traversal. The traversal on a linear data structure. + /// This class defines the interface of the DfsVisit events, and + /// it could be the base of a real visitor class. template 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 - /// reached yet. + /// This function is called for the source node of the DFS. + 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. - /// - /// 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 + /// \brief Called when an arc is examined but its target node is /// 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. - void start(const Node& node) {} - /// \brief Called when we leave the source node of the dfs. + /// This function is called when the DFS steps back from a node. + void leave(const Node& node) {} + /// \brief Called when the DFS steps back on an arc. /// - /// It is called when we leave the source node of the dfs. - void stop(const Node& node) {} - + /// This function is called when the DFS steps back on an arc. + void backtrack(const Arc& arc) {} }; #else template @@ -1130,26 +1145,26 @@ 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 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; }; @@ -1159,21 +1174,20 @@ /// \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 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. - /// \todo named parameter to set this type, function to read and write. + /// It must meet the \ref concepts::ReadWriteMap "ReadWriteMap" concept. typedef typename Digraph::template NodeMap ReachedMap; - /// \brief Instantiates a ReachedMap. + /// \brief Instantiates a \ref ReachedMap. /// /// This function instantiates a \ref ReachedMap. /// \param digraph is the digraph, to which @@ -1184,31 +1198,30 @@ }; - /// %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 - /// is only passed to \ref DfsDefaultTraits. - /// \tparam _Visitor The Visitor object for the algorithm. The - /// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty Visitor which - /// does not observe the Dfs events. If you want to observe the dfs - /// events you should implement your own Visitor class. + /// \ref ListDigraph. The value of _Digraph is not used directly by + /// \ref DfsVisit, it is only passed to \ref DfsVisitDefaultTraits. + /// \tparam _Visitor The Visitor type that is used by the algorithm. + /// \ref DfsVisitor "DfsVisitor<_Digraph>" is an empty visitor, which + /// does not observe the DFS events. If you want to observe the DFS + /// 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. - /// - /// \author Jacint Szabo, Alpar Juttner and Balazs Dezso + /// a DFS visit traits class. #ifdef DOXYGEN template #else @@ -1222,7 +1235,7 @@ /// \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() @@ -1231,13 +1244,16 @@ } }; + ///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: @@ -1247,21 +1263,20 @@ 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 _stack; int _stack_head; - /// \brief Creates the maps if necessary. - /// - /// Creates the maps if necessary. + ///Creates the maps if necessary. + ///\todo Better memory allocation (instead of new). void create_maps() { if(!_reached) { local_reached = true; @@ -1288,9 +1303,9 @@ } }; /// \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 struct DefReachedMap : public DfsVisit< Digraph, Visitor, DefReachedMapTraits > { @@ -1304,25 +1319,22 @@ /// /// Constructor. /// - /// \param digraph the digraph the algorithm will run on. - /// \param visitor The visitor of the algorithm. - /// + /// \param digraph The digraph the algorithm runs on. + /// \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 (*this) DfsVisit &reachedMap(ReachedMap &m) { @@ -1335,21 +1347,23 @@ } 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, - /// first you must call \ref init(), then you can adda source node - /// with \ref addSource(). - /// Finally \ref start() will perform the actual path - /// computation. + /// If you need more control on the execution, first you must call + /// \ref lemon::DfsVisit::init() "init()", then you can add several + /// source nodes with \ref lemon::DfsVisit::addSource() "addSource()". + /// Finally \ref lemon::DfsVisit::start() "start()" will perform the + /// actual path computation. /// @{ + /// \brief Initializes the internal data structures. /// /// Initializes the internal data structures. - /// void init() { create_maps(); _stack.resize(countNodes(*_digraph)); @@ -1359,10 +1373,18 @@ } } - /// \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); @@ -1383,7 +1405,7 @@ /// /// \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); @@ -1417,37 +1439,58 @@ /// /// \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 - bool emptyQueue() { return _stack_head < 0; } + /// to be processed in the queue (stack). + 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. - int queueSize() { return _stack_head + 1; } + /// Returns the number of the nodes to be processed in the queue (stack). + 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 - /// with addSource() before using this function. + /// This method runs the %DFS algorithm from the root node + /// 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 d.start() 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 ) @@ -1458,28 +1501,37 @@ /// /// 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 am[a] true is found. + /// + /// \param am A \c bool (or convertible) arc map. The algorithm + /// will stop when it reaches an arc \c a with am[a] true. + /// + /// \return The reached arc \c a with am[a] 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 - /// will stop when it reaches an arc \c e with em[e] true. - /// - ///\return The reached arc \c e with em[e] true or - ///\c INVALID if no such arc was found. - /// - /// \warning Contrary to \ref Bfs and \ref Dijkstra, \c em is an arc map, + /// \warning Contrary to \ref Bfs and \ref Dijkstra, \c am is an arc map, /// not a node map. - template - Arc start(const EM &em) { - while ( !emptyQueue() && !em[_stack[_stack_head]] ) + template + Arc start(const AM &am) { + 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. - /// \note d.run(s) is just a shortcut of the following code. + /// This method runs the %DFS algorithm from 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); @@ -1491,22 +1543,46 @@ 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 s--t DFS path, + /// if \c t is reachable form \c s, \c 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; + } + + /// \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 - /// - The %DFS tree. - /// - The distance of each node from the root in the %DFS tree. + /// compute the %DFS path to each node. /// - ///\note d.run() is just a shortcut of the following code. + /// The algorithm computes + /// - 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. ///\code - /// d.init(); - /// for (NodeIt it(digraph); it != INVALID; ++it) { - /// if (!d.reached(it)) { - /// d.addSource(it); - /// d.start(); - /// } - /// } + /// d.init(); + /// for (NodeIt n(digraph); n != INVALID; ++n) { + /// if (!d.reached(n)) { + /// d.addSource(n); + /// d.start(); + /// } + /// } ///\endcode void run() { init(); @@ -1517,27 +1593,28 @@ } } } + ///@} /// \name Query Functions /// The result of the %DFS algorithm can be obtained using these /// functions.\n - /// Before the use of these functions, - /// either run() or start() must be called. + /// Either \ref lemon::DfsVisit::run() "run()" or + /// \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 -