class SymListGraph;

     template <typename Key> class DynMapBase

     {

     protected:

       const ListGraph* G; 

     public:

       virtual void add(const Key k) = 0;

       virtual void erase(const Key k) = 0;

       DynMapBase(const ListGraph &_G) : G(&_G) {}

       virtual ~DynMapBase() {}

       friend class ListGraph;

     };

     template <typename T> class EdgeMap;

     template <typename T> class NodeMap;

     ~ListGraph()

     {

       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();

 	  i!=dyn_node_maps.end(); ++i) (**i).G=NULL;

       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();

 	  i!=dyn_edge_maps.end(); ++i) (**i).G=NULL;

     }

       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();

 	  i!=dyn_edge_maps.end(); ++i) (**i).erase(e);

     };

     template <typename T> class NodeMap : public DynMapBase<Node>

     {

       std::vector<T> container;

     public:

       typedef T ValueType;

       typedef Node KeyType;

       NodeMap(const ListGraph &_G) :

 	DynMapBase<Node>(_G), container(_G.maxNodeId())

       {

 	G->dyn_node_maps.push_back(this);

       }

       NodeMap(const ListGraph &_G,const T &t) :

 	DynMapBase<Node>(_G), container(_G.maxNodeId(),t)

       {

 	G->dyn_node_maps.push_back(this);

       }

       NodeMap(const NodeMap<T> &m) :

  	DynMapBase<Node>(*m.G), container(m.container)

       {

  	G->dyn_node_maps.push_back(this);

       }

       template<typename TT> friend class NodeMap;

       ///\todo It can copy between different types.

       ///

       template<typename TT> NodeMap(const NodeMap<TT> &m) :

 	DynMapBase<Node>(*m.G), container(m.container.size())

       {

 	G->dyn_node_maps.push_back(this);

 	typename std::vector<TT>::const_iterator i;

 	for(typename std::vector<TT>::const_iterator i=m.container.begin();

 	    i!=m.container.end();

 	    i++)

 	  container.push_back(*i);

       }

       ~NodeMap()

       {

 	if(G) {

 	  std::vector<DynMapBase<Node>* >::iterator i;

 	  for(i=G->dyn_node_maps.begin();

 	      i!=G->dyn_node_maps.end() && *i!=this; ++i) ;

 	  //if(*i==this) G->dyn_node_maps.erase(i); //FIXME: Way too slow...

 	  //A better way to do that: (Is this really important?)

 	  if(*i==this) {

 	    *i=G->dyn_node_maps.back();

 	    G->dyn_node_maps.pop_back();

 	  }

 	}

       }

       void add(const Node k) 

       {

 	if(k.n>=int(container.size())) container.resize(k.n+1);

       }

       void erase(const Node) { }

       void set(Node n, T a) { container[n.n]=a; }

       //'T& operator[](Node n)' would be wrong here

       typename std::vector<T>::reference

       operator[](Node n) { return container[n.n]; }

       //'const T& operator[](Node n)' would be wrong here

       typename std::vector<T>::const_reference 

       operator[](Node n) const { return container[n.n]; }

       ///\warning There is no safety check at all!

       ///Using operator = between maps attached to different graph may

       ///cause serious problem.

       ///\todo Is this really so?

       ///\todo It can copy between different types.

       const NodeMap<T>& operator=(const NodeMap<T> &m)

       {

 	container = m.container;

 	return *this;

       }

       template<typename TT>

       const NodeMap<T>& operator=(const NodeMap<TT> &m)

       {

 	std::copy(m.container.begin(), m.container.end(), container.begin());

 	return *this;

       }

       void update() {}    //Useless for Dynamic Maps

       void update(T a) {}  //Useless for Dynamic Maps

     };

     template <typename T> class EdgeMap : public DynMapBase<Edge>

     {

     protected:

       std::vector<T> container;

     public:

       typedef T ValueType;

       typedef Edge KeyType;

       EdgeMap(const ListGraph &_G) :

 	DynMapBase<Edge>(_G), container(_G.maxEdgeId())

       {

 	//FIXME: What if there are empty Id's?

 	//FIXME: Can I use 'this' in a constructor?

 	G->dyn_edge_maps.push_back(this);

       }

       EdgeMap(const ListGraph &_G,const T &t) :

 	DynMapBase<Edge>(_G), container(_G.maxEdgeId(),t)

       {

 	G->dyn_edge_maps.push_back(this);

       } 

       EdgeMap(const EdgeMap<T> &m) :

  	DynMapBase<Edge>(*m.G), container(m.container)

       {

  	G->dyn_edge_maps.push_back(this);

       }

       template<typename TT> friend class EdgeMap;

       ///\todo It can copy between different types.

       ///

       template<typename TT> EdgeMap(const EdgeMap<TT> &m) :

 	DynMapBase<Edge>(*m.G), container(m.container.size())

       {

 	G->dyn_edge_maps.push_back(this);

 	typename std::vector<TT>::const_iterator i;

 	for(typename std::vector<TT>::const_iterator i=m.container.begin();

 	    i!=m.container.end();

 	    i++)

 	  container.push_back(*i);

       }

       ~EdgeMap()

       {

 	if(G) {

 	  std::vector<DynMapBase<Edge>* >::iterator i;

 	  for(i=G->dyn_edge_maps.begin();

 	      i!=G->dyn_edge_maps.end() && *i!=this; ++i) ;

 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...

 	  //A better way to do that: (Is this really important?)

 	  if(*i==this) {

 	    *i=G->dyn_edge_maps.back();

 	    G->dyn_edge_maps.pop_back();

 	  }

 	}

       }

       void add(const Edge k) 

       {

 	if(k.n>=int(container.size())) container.resize(k.n+1);

       }

       void erase(const Edge) { }

       void set(Edge n, T a) { container[n.n]=a; }

       //T get(Edge n) const { return container[n.n]; }

       typename std::vector<T>::reference

       operator[](Edge n) { return container[n.n]; }

       typename std::vector<T>::const_reference

       operator[](Edge n) const { return container[n.n]; }

       ///\warning There is no safety check at all!

       ///Using operator = between maps attached to different graph may

       ///cause serious problem.

       ///\todo Is this really so?

       ///\todo It can copy between different types.

       const EdgeMap<T>& operator=(const EdgeMap<T> &m)

       {

 	container = m.container;

 	return *this;

       }

       template<typename TT>

       const EdgeMap<T>& operator=(const EdgeMap<TT> &m)

       {

 	std::copy(m.container.begin(), m.container.end(), container.begin());

 	return *this;

       }

       void update() {}    //Useless for DynMaps

       void update(T a) {}  //Useless for DynMaps

   class SymListGraph : public ListGraph

   {

   public:

     template<typename T> class SymEdgeMap;

     template<typename T> friend class SymEdgeMap;

     SymListGraph() : ListGraph() { }

     SymListGraph(const ListGraph &_g) : ListGraph(_g) { }

     ///Adds a pair of oppositely directed edges to the graph.

     Edge addEdge(Node u, Node v)

     {

       Edge e = ListGraph::addEdge(u,v);

       ListGraph::addEdge(v,u);

       return e;

     }

     void erase(Node n) { ListGraph::erase(n); }

     ///The oppositely directed edge.

     ///Returns the oppositely directed

     ///pair of the edge \c e.

     Edge opposite(Edge e) const

     {

       Edge f;

       f.idref() = e.idref() - 2*(e.idref()%2) + 1;

       return f;

     }

     ///Removes a pair of oppositely directed edges to the graph.

     void erase(Edge e) {

       ListGraph::erase(opposite(e));

       ListGraph::erase(e);

     }

     ///Common data storage for the edge pairs.

     ///This map makes it possible to store data shared by the oppositely

     ///directed pairs of edges.

     template <typename T> class SymEdgeMap : public DynMapBase<Edge>

     {

       std::vector<T> container;

     public:

       typedef T ValueType;

       typedef Edge KeyType;

       SymEdgeMap(const SymListGraph &_G) :

 	DynMapBase<Edge>(_G), container(_G.maxEdgeId()/2)

       {

 	static_cast<const SymListGraph*>(G)->dyn_edge_maps.push_back(this);

       }

       SymEdgeMap(const SymListGraph &_G,const T &t) :

 	DynMapBase<Edge>(_G), container(_G.maxEdgeId()/2,t)

       {

 	G->dyn_edge_maps.push_back(this);

       }

       SymEdgeMap(const SymEdgeMap<T> &m) :

  	DynMapBase<SymEdge>(*m.G), container(m.container)

       {

  	G->dyn_node_maps.push_back(this);

       }

       //      template<typename TT> friend class SymEdgeMap;

       ///\todo It can copy between different types.

       ///

       template<typename TT> SymEdgeMap(const SymEdgeMap<TT> &m) :

 	DynMapBase<SymEdge>(*m.G), container(m.container.size())

       {

 	G->dyn_node_maps.push_back(this);

 	typename std::vector<TT>::const_iterator i;

 	for(typename std::vector<TT>::const_iterator i=m.container.begin();

 	    i!=m.container.end();

 	    i++)

 	  container.push_back(*i);

       }

       ~SymEdgeMap()

       {

 	if(G) {

 	  std::vector<DynMapBase<Edge>* >::iterator i;

 	  for(i=static_cast<const SymListGraph*>(G)->dyn_edge_maps.begin();

 	      i!=static_cast<const SymListGraph*>(G)->dyn_edge_maps.end()

 		&& *i!=this; ++i) ;

 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...

 	  //A better way to do that: (Is this really important?)

 	  if(*i==this) {

 	    *i=static_cast<const SymListGraph*>(G)->dyn_edge_maps.back();

 	    static_cast<const SymListGraph*>(G)->dyn_edge_maps.pop_back();

 	  }

 	}

       }

       void add(const Edge k) 

       {

 	if(!k.idref()%2&&k.idref()/2>=int(container.size()))

 	  container.resize(k.idref()/2+1);

       }

       void erase(const Edge k) { }

       void set(Edge n, T a) { container[n.idref()/2]=a; }

       //T get(Edge n) const { return container[n.idref()/2]; }

       typename std::vector<T>::reference

       operator[](Edge n) { return container[n.idref()/2]; }

       typename std::vector<T>::const_reference

       operator[](Edge n) const { return container[n.idref()/2]; }

       ///\warning There is no safety check at all!

       ///Using operator = between maps attached to different graph may

       ///cause serious problem.

       ///\todo Is this really so?

       ///\todo It can copy between different types.

       const SymEdgeMap<T>& operator=(const SymEdgeMap<T> &m)

       {

 	container = m.container;

 	return *this;

       }

       template<typename TT>

       const SymEdgeMap<T>& operator=(const SymEdgeMap<TT> &m)

       {

 	std::copy(m.container.begin(), m.container.end(), container.begin());

 	return *this;

       }

       void update() {}    //Useless for DynMaps

       void update(T a) {}  //Useless for DynMaps

     };