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

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

  *

  *

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

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

  *

  *

  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

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

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

  *

  *

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

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

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

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

 #include<lemon/connectivity.h>

 #include<lemon/connectivity.h>

 #include <list>

 #include <list>

 /// \ingroup graph_properties

 /// \ingroup graph_properties

 /// \file

 /// \file

 /// property.

 /// property.

 ///

 ///

 ///This file provides Euler tour iterators and a function to check

 ///This file provides Euler tour iterators and a function to check

 ///if a (di)graph is \e Eulerian.

 ///if a (di)graph is \e Eulerian.

   /// \ingroup graph_prop

   /// \ingroup graph_prop

   ///This iterator provides an Euler tour (Eulerian circuit) of a \e directed

   ///This iterator provides an Euler tour (Eulerian circuit) of a \e directed

   ///graph (if there exists) and it converts to the \c Arc type of the digraph.

   ///graph (if there exists) and it converts to the \c Arc type of the digraph.

   ///

   ///

   ///For example, if the given digraph has an Euler tour (i.e it has only one

   ///For example, if the given digraph has an Euler tour (i.e it has only one

   ///for all nodes), then the following code will put the arcs of \c g

   ///for all nodes), then the following code will put the arcs of \c g

   ///to the vector \c et according to an Euler tour of \c g.

   ///to the vector \c et according to an Euler tour of \c g.

   ///\code

   ///\code

   ///  std::vector<ListDigraph::Arc> et;

   ///  std::vector<ListDigraph::Arc> et;

   ///  for(DiEulerIt<ListDigraph> e(g); e!=INVALID; ++e)

   ///  for(DiEulerIt<ListDigraph> e(g); e!=INVALID; ++e)

   /// \ingroup graph_properties

   /// \ingroup graph_properties

   ///This iterator provides an Euler tour (Eulerian circuit) of an

   ///This iterator provides an Euler tour (Eulerian circuit) of an

   ///\e undirected graph (if there exists) and it converts to the \c Arc

   ///\e undirected graph (if there exists) and it converts to the \c Arc

   ///and \c Edge types of the graph.

   ///and \c Edge types of the graph.

   ///

   ///

   ///non-trivial component and the degree of each node is even),

   ///non-trivial component and the degree of each node is even),

   ///the following code will print the arc IDs according to an

   ///the following code will print the arc IDs according to an

   ///Euler tour of \c g.

   ///Euler tour of \c g.

   ///\code

   ///\code

   ///  for(EulerIt<ListGraph> e(g); e!=INVALID; ++e) {

   ///  for(EulerIt<ListGraph> e(g); e!=INVALID; ++e) {

   ///    std::cout << g.id(Edge(e)) << std::eol;

   ///    std::cout << g.id(Edge(e)) << std::eol;

   ///  }

   ///  }

   ///\endcode

   ///\endcode

   ///arcs in order to indicate the direction of the tour.

   ///arcs in order to indicate the direction of the tour.

   ///(But arcs convert to edges, of course.)

   ///(But arcs convert to edges, of course.)

   ///

   ///

   ///If \c g has no Euler tour, then the resulted walk will not be closed

   ///If \c g has no Euler tour, then the resulted walk will not be closed

   ///or not contain all edges.

   ///or not contain all edges.

     ///Postfix incrementation

     ///Postfix incrementation

     /// Postfix incrementation.

     /// Postfix incrementation.

     ///

     ///

     ///an \c Edge), not an \ref EulerIt, as one may expect.

     ///an \c Edge), not an \ref EulerIt, as one may expect.

     Arc operator++(int)

     Arc operator++(int)

     {

     {

       Arc e=*this;

       Arc e=*this;

       ++(*this);

       ++(*this);