RhodeCode

/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library.

 *

 * Copyright (C) 2003-2009

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

#include <lemon/core.h>

#include <lemon/concept_check.h>

namespace lemon {

  template <typename _Digraph, typename _PredMap>

  class PredMapPath {

  public:

    typedef True RevPathTag;

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

    typedef _PredMap PredMap;

    PredMapPath(const Digraph& _digraph, const PredMap& _predMap,

                typename Digraph::Node _target)

      : digraph(_digraph), predMap(_predMap), target(_target) {}

    int length() const {

      int len = 0;

      typename Digraph::Node node = target;

      typename Digraph::Arc arc;

      while ((arc = predMap[node]) != INVALID) {

        node = digraph.source(arc);

        ++len;

      }

      return len;

    }

    bool empty() const {

      return predMap[target] != INVALID;

    }

    class RevArcIt {

    public:

      RevArcIt() {}

      RevArcIt(Invalid) : path(0), current(INVALID) {}

      RevArcIt(const PredMapPath& _path)

        : path(&_path), current(_path.target) {

        if (path->predMap[current] == INVALID) current = INVALID;

      }

      operator const typename Digraph::Arc() const {

        return path->predMap[current];

      }

      RevArcIt& operator++() {

        current = path->digraph.source(path->predMap[current]);

        if (path->predMap[current] == INVALID) current = INVALID;

        return *this;

      }

      bool operator==(const RevArcIt& e) const {

        return current == e.current;

      }

      bool operator!=(const RevArcIt& e) const {

        return current != e.current;

      }

      bool operator<(const RevArcIt& e) const {

        return current < e.current;

      }

    private:

      const PredMapPath* path;

      typename Digraph::Node current;

    };

  private:

    const Digraph& digraph;

    const PredMap& predMap;

    typename Digraph::Node target;

  };

  template <typename _Digraph, typename _PredMatrixMap>

  class PredMatrixMapPath {

  public:

    typedef True RevPathTag;

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

    typedef _PredMatrixMap PredMatrixMap;

    PredMatrixMapPath(const Digraph& _digraph,

                      const PredMatrixMap& _predMatrixMap,

                      typename Digraph::Node _source,

                      typename Digraph::Node _target)

      : digraph(_digraph), predMatrixMap(_predMatrixMap),

        source(_source), target(_target) {}

    int length() const {

      int len = 0;

      typename Digraph::Node node = target;

      typename Digraph::Arc arc;

      while ((arc = predMatrixMap(source, node)) != INVALID) {

        node = digraph.source(arc);

        ++len;

      }

      return len;

    }

    bool empty() const {

      return source != target;

    }

    class RevArcIt {

    public:

      RevArcIt() {}

      RevArcIt(Invalid) : path(0), current(INVALID) {}

      RevArcIt(const PredMatrixMapPath& _path)

        : path(&_path), current(_path.target) {

        if (path->predMatrixMap(path->source, current) == INVALID)

          current = INVALID;

      }

      operator const typename Digraph::Arc() const {

        return path->predMatrixMap(path->source, current);

      }

      RevArcIt& operator++() {

        current =

          path->digraph.source(path->predMatrixMap(path->source, current));

        if (path->predMatrixMap(path->source, current) == INVALID)

          current = INVALID;

        return *this;

      }

      bool operator==(const RevArcIt& e) const {

        return current == e.current;

      }

      bool operator!=(const RevArcIt& e) const {

        return current != e.current;

      }

      bool operator<(const RevArcIt& e) const {

        return current < e.current;

      }

    private:

      const PredMatrixMapPath* path;

      typename Digraph::Node current;

    };

  private:

    const Digraph& digraph;

    const PredMatrixMap& predMatrixMap;

    typename Digraph::Node source;

    typename Digraph::Node target;

  };

}

#endif

/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library.

 *

 * Copyright (C) 2003-2009

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

#include <string>

namespace lemon {

  namespace bits {

    void getWinProcTimes(double &rtime,

                         double &utime, double &stime,

                         double &cutime, double &cstime);

    std::string getWinFormattedDate();

    int getWinRndSeed();

  }

}

#endif

/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library.

 *

 * Copyright (C) 2003-2009

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

///\ingroup graph_concepts

///\file

///\brief The concept of directed graphs.

#include <lemon/core.h>

#include <lemon/concepts/maps.h>

#include <lemon/concept_check.h>

#include <lemon/concepts/graph_components.h>

namespace lemon {

  namespace concepts {

    /// \ingroup graph_concepts

    ///

    /// \brief Class describing the concept of directed graphs.

    ///

    /// This class describes the \ref concept "concept" of the

    /// immutable directed digraphs.

    ///

    /// Note that actual digraph implementation like @ref ListDigraph or

    /// @ref SmartDigraph may have several additional functionality.

    ///

    /// \sa concept

    class Digraph {

    private:

      ///Digraphs are \e not copy constructible. Use DigraphCopy() instead.

      ///Digraphs are \e not copy constructible. Use DigraphCopy() instead.

      ///

      Digraph(const Digraph &) {};

      ///\brief Assignment of \ref Digraph "Digraph"s to another ones are

      ///\e not allowed. Use DigraphCopy() instead.

      ///Assignment of \ref Digraph "Digraph"s to another ones are

      ///\e not allowed.  Use DigraphCopy() instead.

      void operator=(const Digraph &) {}

    public:

      ///\e

      /// Defalult constructor.

      /// Defalult constructor.

      ///

      Digraph() { }

      /// Class for identifying a node of the digraph

      /// This class identifies a node of the digraph. It also serves

      /// as a base class of the node iterators,

      /// thus they will convert to this type.

      class Node {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        Node() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        Node(const Node&) { }

        /// Invalid constructor \& conversion.

        /// This constructor initializes the iterator to be invalid.

        /// \sa Invalid for more details.

        Node(Invalid) { }

        /// Equality operator

        /// Two iterators are equal if and only if they point to the

        /// same object or both are invalid.

        bool operator==(Node) const { return true; }

        /// Inequality operator

        /// \sa operator==(Node n)

        ///

        bool operator!=(Node) const { return true; }

        /// Artificial ordering operator.

        /// To allow the use of digraph descriptors as key type in std::map or

        /// similar associative container we require this.

        ///

        /// \note This operator only have to define some strict ordering of

        /// the items; this order has nothing to do with the iteration

        /// ordering of the items.

        bool operator<(Node) const { return false; }

      };

      /// This iterator goes through each node.

      /// This iterator goes through each node.

      /// Its usage is quite simple, for example you can count the number

      /// of nodes in digraph \c g of type \c Digraph like this:

      ///\code

      /// int count=0;

      /// for (Digraph::NodeIt n(g); n!=INVALID; ++n) ++count;

      ///\endcode

      class NodeIt : public Node {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        NodeIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        NodeIt(const NodeIt& n) : Node(n) { }

        /// Invalid constructor \& conversion.

        /// Initialize the iterator to be invalid.

        /// \sa Invalid for more details.

        NodeIt(Invalid) { }

        /// Sets the iterator to the first node.

        /// Sets the iterator to the first node of \c g.

        ///

        NodeIt(const Digraph&) { }

        /// Node -> NodeIt conversion.

        /// Sets the iterator to the node of \c the digraph pointed by

        /// the trivial iterator.

        /// This feature necessitates that each time we

        /// iterate the arc-set, the iteration order is the same.

        NodeIt(const Digraph&, const Node&) { }

        /// Next node.

        /// Assign the iterator to the next node.

        ///

        NodeIt& operator++() { return *this; }

      };

      /// Class for identifying an arc of the digraph

      /// This class identifies an arc of the digraph. It also serves

      /// as a base class of the arc iterators,

      /// thus they will convert to this type.

      class Arc {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        Arc() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        Arc(const Arc&) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        Arc(Invalid) { }

        /// Equality operator

        /// Two iterators are equal if and only if they point to the

        /// same object or both are invalid.

        bool operator==(Arc) const { return true; }

        /// Inequality operator

        /// \sa operator==(Arc n)

        ///

        bool operator!=(Arc) const { return true; }

        /// Artificial ordering operator.

        /// To allow the use of digraph descriptors as key type in std::map or

        /// similar associative container we require this.

        ///

        /// \note This operator only have to define some strict ordering of

        /// the items; this order has nothing to do with the iteration

        /// ordering of the items.

        bool operator<(Arc) const { return false; }

      };

      /// This iterator goes trough the outgoing arcs of a node.

      /// This iterator goes trough the \e outgoing arcs of a certain node

      /// of a digraph.

      /// Its usage is quite simple, for example you can count the number

      /// of outgoing arcs of a node \c n

      /// in digraph \c g of type \c Digraph as follows.

      ///\code

      /// int count=0;

      /// for (Digraph::OutArcIt e(g, n); e!=INVALID; ++e) ++count;

      ///\endcode

      class OutArcIt : public Arc {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        OutArcIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        OutArcIt(const OutArcIt& e) : Arc(e) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        OutArcIt(Invalid) { }

        /// This constructor sets the iterator to the first outgoing arc.

        /// This constructor sets the iterator to the first outgoing arc of

        /// the node.

        OutArcIt(const Digraph&, const Node&) { }

        /// Arc -> OutArcIt conversion

        /// Sets the iterator to the value of the trivial iterator.

        /// This feature necessitates that each time we

        /// iterate the arc-set, the iteration order is the same.

        OutArcIt(const Digraph&, const Arc&) { }

        ///Next outgoing arc

        /// Assign the iterator to the next

        /// outgoing arc of the corresponding node.

        OutArcIt& operator++() { return *this; }

      };

      /// This iterator goes trough the incoming arcs of a node.

      /// This iterator goes trough the \e incoming arcs of a certain node

      /// of a digraph.

      /// Its usage is quite simple, for example you can count the number

      /// of outgoing arcs of a node \c n

      /// in digraph \c g of type \c Digraph as follows.

      ///\code

      /// int count=0;

      /// for(Digraph::InArcIt e(g, n); e!=INVALID; ++e) ++count;

      ///\endcode

      class InArcIt : public Arc {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        InArcIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        InArcIt(const InArcIt& e) : Arc(e) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        InArcIt(Invalid) { }

        /// This constructor sets the iterator to first incoming arc.

        /// This constructor set the iterator to the first incoming arc of

        /// the node.

        InArcIt(const Digraph&, const Node&) { }

        /// Arc -> InArcIt conversion

        /// Sets the iterator to the value of the trivial iterator \c e.

        /// This feature necessitates that each time we

        /// iterate the arc-set, the iteration order is the same.

        InArcIt(const Digraph&, const Arc&) { }

        /// Next incoming arc

        /// Assign the iterator to the next inarc of the corresponding node.

        ///

        InArcIt& operator++() { return *this; }

      };

      /// This iterator goes through each arc.

      /// This iterator goes through each arc of a digraph.

      /// Its usage is quite simple, for example you can count the number

      /// of arcs in a digraph \c g of type \c Digraph as follows:

      ///\code

      /// int count=0;

      /// for(Digraph::ArcIt e(g); e!=INVALID; ++e) ++count;

      ///\endcode

      class ArcIt : public Arc {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        ArcIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        ArcIt(const ArcIt& e) : Arc(e) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        ArcIt(Invalid) { }

        /// This constructor sets the iterator to the first arc.

        /// This constructor sets the iterator to the first arc of \c g.

        ///@param g the digraph

        ArcIt(const Digraph& g) { ignore_unused_variable_warning(g); }

        /// Arc -> ArcIt conversion

        /// Sets the iterator to the value of the trivial iterator \c e.

        /// This feature necessitates that each time we

        /// iterate the arc-set, the iteration order is the same.

        ArcIt(const Digraph&, const Arc&) { }

        ///Next arc

        /// Assign the iterator to the next arc.

        ArcIt& operator++() { return *this; }

      };

      ///Gives back the target node of an arc.

      ///Gives back the target node of an arc.

      ///

      Node target(Arc) const { return INVALID; }

      ///Gives back the source node of an arc.

      ///Gives back the source node of an arc.

      ///

      Node source(Arc) const { return INVALID; }

      /// \brief Returns the ID of the node.

      int id(Node) const { return -1; }

      /// \brief Returns the ID of the arc.

      int id(Arc) const { return -1; }

      /// \brief Returns the node with the given ID.

      ///

      /// \pre The argument should be a valid node ID in the graph.

      Node nodeFromId(int) const { return INVALID; }

      /// \brief Returns the arc with the given ID.

      ///

      /// \pre The argument should be a valid arc ID in the graph.

      Arc arcFromId(int) const { return INVALID; }

      /// \brief Returns an upper bound on the node IDs.

      int maxNodeId() const { return -1; }

      /// \brief Returns an upper bound on the arc IDs.

      int maxArcId() const { return -1; }

      void first(Node&) const {}

      void next(Node&) const {}

      void first(Arc&) const {}

      void next(Arc&) const {}

      void firstIn(Arc&, const Node&) const {}

      void nextIn(Arc&) const {}

      void firstOut(Arc&, const Node&) const {}

      void nextOut(Arc&) const {}

      // The second parameter is dummy.

      Node fromId(int, Node) const { return INVALID; }

      // The second parameter is dummy.

      Arc fromId(int, Arc) const { return INVALID; }

      // Dummy parameter.

      int maxId(Node) const { return -1; }

      // Dummy parameter.

      int maxId(Arc) const { return -1; }

      /// \brief The base node of the iterator.

      ///

      /// Gives back the base node of the iterator.

      /// It is always the target of the pointed arc.

      Node baseNode(const InArcIt&) const { return INVALID; }

      /// \brief The running node of the iterator.

      ///

      /// Gives back the running node of the iterator.

      /// It is always the source of the pointed arc.

      Node runningNode(const InArcIt&) const { return INVALID; }

      /// \brief The base node of the iterator.

      ///

      /// Gives back the base node of the iterator.

      /// It is always the source of the pointed arc.

      Node baseNode(const OutArcIt&) const { return INVALID; }

      /// \brief The running node of the iterator.

      ///

      /// Gives back the running node of the iterator.

      /// It is always the target of the pointed arc.

      Node runningNode(const OutArcIt&) const { return INVALID; }

      /// \brief The opposite node on the given arc.

      ///

      /// Gives back the opposite node on the given arc.

      Node oppositeNode(const Node&, const Arc&) const { return INVALID; }

      /// \brief Read write map of the nodes to type \c T.

      ///

      /// ReadWrite map of the nodes to type \c T.

      /// \sa Reference

      template<class T>

      class NodeMap : public ReadWriteMap< Node, T > {

      public:

        ///\e

        NodeMap(const Digraph&) { }

        ///\e

        NodeMap(const Digraph&, T) { }

      private:

        ///Copy constructor

        NodeMap(const NodeMap& nm) : ReadWriteMap< Node, T >(nm) { }

        ///Assignment operator

        template <typename CMap>

        NodeMap& operator=(const CMap&) {

          checkConcept<ReadMap<Node, T>, CMap>();

          return *this;

        }

      };

      /// \brief Read write map of the arcs to type \c T.

      ///

      /// Reference map of the arcs to type \c T.

      /// \sa Reference

      template<class T>

      class ArcMap : public ReadWriteMap<Arc,T> {

      public:

        ///\e

        ArcMap(const Digraph&) { }

        ///\e

        ArcMap(const Digraph&, T) { }

      private:

        ///Copy constructor

        ArcMap(const ArcMap& em) : ReadWriteMap<Arc,T>(em) { }

        ///Assignment operator

        template <typename CMap>

        ArcMap& operator=(const CMap&) {

          checkConcept<ReadMap<Arc, T>, CMap>();

          return *this;

        }

      };

      template <typename _Digraph>

      struct Constraints {

        void constraints() {

          checkConcept<IterableDigraphComponent<>, _Digraph>();

          checkConcept<IDableDigraphComponent<>, _Digraph>();

          checkConcept<MappableDigraphComponent<>, _Digraph>();

        }

      };

    };

  } //namespace concepts

} //namespace lemon

/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library.

 *

 * Copyright (C) 2003-2009

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

///\ingroup graph_concepts

///\file

///\brief The concept of Undirected Graphs.

#include <lemon/concepts/graph_components.h>

#include <lemon/core.h>

namespace lemon {

  namespace concepts {

    /// \ingroup graph_concepts

    ///

    /// \brief Class describing the concept of Undirected Graphs.

    ///

    /// This class describes the common interface of all Undirected

    /// Graphs.

    ///

    /// As all concept describing classes it provides only interface

    /// without any sensible implementation. So any algorithm for

    /// undirected graph should compile with this class, but it will not

    /// run properly, of course.

    ///

    /// The LEMON undirected graphs also fulfill the concept of

    /// directed graphs (\ref lemon::concepts::Digraph "Digraph

    /// Concept"). Each edges can be seen as two opposite

    /// directed arc and consequently the undirected graph can be

    /// seen as the direceted graph of these directed arcs. The

    /// Graph has the Edge inner class for the edges and

    /// the Arc type for the directed arcs. The Arc type is

    /// convertible to Edge or inherited from it so from a directed

    /// arc we can get the represented edge.

    ///

    /// In the sense of the LEMON each edge has a default

    /// direction (it should be in every computer implementation,

    /// because the order of edge's nodes defines an

    /// orientation). With the default orientation we can define that

    /// the directed arc is forward or backward directed. With the \c

    /// direction() and \c direct() function we can get the direction

    /// of the directed arc and we can direct an edge.

    ///

    /// The EdgeIt is an iterator for the edges. We can use

    /// the EdgeMap to map values for the edges. The InArcIt and

    /// OutArcIt iterates on the same edges but with opposite

    /// direction. The IncEdgeIt iterates also on the same edges

    /// as the OutArcIt and InArcIt but it is not convertible to Arc just

    /// to Edge.

    class Graph {

    public:

      /// \brief The undirected graph should be tagged by the

      /// UndirectedTag.

      ///

      /// The undirected graph should be tagged by the UndirectedTag. This

      /// tag helps the enable_if technics to make compile time

      /// specializations for undirected graphs.

      typedef True UndirectedTag;

      /// \brief The base type of node iterators,

      /// or in other words, the trivial node iterator.

      ///

      /// This is the base type of each node iterator,

      /// thus each kind of node iterator converts to this.

      /// More precisely each kind of node iterator should be inherited

      /// from the trivial node iterator.

      class Node {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        Node() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        Node(const Node&) { }

        /// Invalid constructor \& conversion.

        /// This constructor initializes the iterator to be invalid.

        /// \sa Invalid for more details.

        Node(Invalid) { }

        /// Equality operator

        /// Two iterators are equal if and only if they point to the

        /// same object or both are invalid.

        bool operator==(Node) const { return true; }

        /// Inequality operator

        /// \sa operator==(Node n)

        ///

        bool operator!=(Node) const { return true; }

        /// Artificial ordering operator.

        /// To allow the use of graph descriptors as key type in std::map or

        /// similar associative container we require this.

        ///

        /// \note This operator only have to define some strict ordering of

        /// the items; this order has nothing to do with the iteration

        /// ordering of the items.

        bool operator<(Node) const { return false; }

      };

      /// This iterator goes through each node.

      /// This iterator goes through each node.

      /// Its usage is quite simple, for example you can count the number

      /// of nodes in graph \c g of type \c Graph like this:

      ///\code

      /// int count=0;

      /// for (Graph::NodeIt n(g); n!=INVALID; ++n) ++count;

      ///\endcode

      class NodeIt : public Node {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        NodeIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        NodeIt(const NodeIt& n) : Node(n) { }

        /// Invalid constructor \& conversion.

        /// Initialize the iterator to be invalid.

        /// \sa Invalid for more details.

        NodeIt(Invalid) { }

        /// Sets the iterator to the first node.

        /// Sets the iterator to the first node of \c g.

        ///

        NodeIt(const Graph&) { }

        /// Node -> NodeIt conversion.

        /// Sets the iterator to the node of \c the graph pointed by

        /// the trivial iterator.

        /// This feature necessitates that each time we

        /// iterate the arc-set, the iteration order is the same.

        NodeIt(const Graph&, const Node&) { }

        /// Next node.

        /// Assign the iterator to the next node.

        ///

        NodeIt& operator++() { return *this; }

      };

      /// The base type of the edge iterators.

      /// The base type of the edge iterators.

      ///

      class Edge {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        Edge() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        Edge(const Edge&) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        Edge(Invalid) { }

        /// Equality operator

        /// Two iterators are equal if and only if they point to the

        /// same object or both are invalid.

        bool operator==(Edge) const { return true; }

        /// Inequality operator

        /// \sa operator==(Edge n)

        ///

        bool operator!=(Edge) const { return true; }

        /// Artificial ordering operator.

        /// To allow the use of graph descriptors as key type in std::map or

        /// similar associative container we require this.

        ///

        /// \note This operator only have to define some strict ordering of

        /// the items; this order has nothing to do with the iteration

        /// ordering of the items.

        bool operator<(Edge) const { return false; }

      };

      /// This iterator goes through each edge.

      /// This iterator goes through each edge of a graph.

      /// Its usage is quite simple, for example you can count the number

      /// of edges in a graph \c g of type \c Graph as follows:

      ///\code

      /// int count=0;

      /// for(Graph::EdgeIt e(g); e!=INVALID; ++e) ++count;

      ///\endcode

      class EdgeIt : public Edge {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        EdgeIt() { }

        /// Copy constructor.

        /// Copy constructor.

        ///

        EdgeIt(const EdgeIt& e) : Edge(e) { }

        /// Initialize the iterator to be invalid.

        /// Initialize the iterator to be invalid.

        ///

        EdgeIt(Invalid) { }

        /// This constructor sets the iterator to the first edge.

        /// This constructor sets the iterator to the first edge.

        EdgeIt(const Graph&) { }

        /// Edge -> EdgeIt conversion

        /// Sets the iterator to the value of the trivial iterator.

        /// This feature necessitates that each time we

        /// iterate the edge-set, the iteration order is the

        /// same.

        EdgeIt(const Graph&, const Edge&) { }

        /// Next edge

        /// Assign the iterator to the next edge.

        EdgeIt& operator++() { return *this; }

      };

      /// \brief This iterator goes trough the incident undirected

      /// arcs of a node.

      ///

      /// This iterator goes trough the incident edges

      /// of a certain node of a graph. You should assume that the

      /// loop arcs will be iterated twice.

      ///

      /// Its usage is quite simple, for example you can compute the

      /// degree (i.e. count the number of incident arcs of a node \c n

      /// in graph \c g of type \c Graph as follows.

      ///

      ///\code

      /// int count=0;

      /// for(Graph::IncEdgeIt e(g, n); e!=INVALID; ++e) ++count;

      ///\endcode

      class IncEdgeIt : public Edge {

      public:

        /// Default constructor

        /// @warning The default constructor sets the iterator

        /// to an undefined value.

        IncEdgeIt() { }

        /// Copy constructor.

/* -*- mode: C++; indent-tabs-mode: nil; -*-

 *

 * This file is a part of LEMON, a generic C++ optimization library.

 *

 * Copyright (C) 2003-2009

 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

 * (Egervary Research Group on Combinatorial Optimization, EGRES).

 *

 * Permission to use, modify and distribute this software is granted

 * provided that this copyright notice appears in all copies. For

 * precise terms see the accompanying LICENSE file.

 *

 * This software is provided "AS IS" with no warranty of any kind,

 * express or implied, and with no claim as to its suitability for any

 * purpose.

 *

 */

///\ingroup graph_concepts

///\file

///\brief The concept of graph components.

#include <lemon/core.h>

#include <lemon/concepts/maps.h>

#include <lemon/bits/alteration_notifier.h>

namespace lemon {

  namespace concepts {

    /// \brief Skeleton class for graph Node and Arc types

    ///

    /// This class describes the interface of Node and Arc (and Edge

    /// in undirected graphs) subtypes of graph types.

    ///

    /// \note This class is a template class so that we can use it to

    /// create graph skeleton classes. The reason for this is than Node

    /// and Arc types should \em not derive from the same base class.

    /// For Node you should instantiate it with character 'n' and for Arc

    /// with 'a'.

#ifndef DOXYGEN

    template <char _selector = '0'>

#endif

    class GraphItem {

    public:

      /// \brief Default constructor.

      ///

      /// \warning The default constructor is not required to set

      /// the item to some well-defined value. So you should consider it

      /// as uninitialized.

      GraphItem() {}

      /// \brief Copy constructor.

      ///

      /// Copy constructor.

      ///

      GraphItem(const GraphItem &) {}

      /// \brief Invalid constructor \& conversion.

      ///

      /// This constructor initializes the item to be invalid.

      /// \sa Invalid for more details.

      GraphItem(Invalid) {}

      /// \brief Assign operator for nodes.

      ///

      /// The nodes are assignable.

      ///

      GraphItem& operator=(GraphItem const&) { return *this; }

      /// \brief Equality operator.

      ///

      /// Two iterators are equal if and only if they represents the

      /// same node in the graph or both are invalid.

      bool operator==(GraphItem) const { return false; }

      /// \brief Inequality operator.

      ///

      /// \sa operator==(const Node& n)

      ///

      bool operator!=(GraphItem) const { return false; }

      /// \brief Artificial ordering operator.

      ///

      /// To allow the use of graph descriptors as key type in std::map or

      /// similar associative container we require this.

      ///

      /// \note This operator only have to define some strict ordering of

      /// the items; this order has nothing to do with the iteration

      /// ordering of the items.

      bool operator<(GraphItem) const { return false; }

      template<typename _GraphItem>

      struct Constraints {

        void constraints() {

          _GraphItem i1;

          _GraphItem i2 = i1;

          _GraphItem i3 = INVALID;

          i1 = i2 = i3;

          bool b;

          //          b = (ia == ib) && (ia != ib) && (ia < ib);

          b = (ia == ib) && (ia != ib);