diff -r f2ea4aac9ada -r c94ef40a22ce src/lemon/list_graph.h
--- a/src/lemon/list_graph.h	Mon Oct 25 13:29:46 2004 +0000
+++ b/src/lemon/list_graph.h	Wed Oct 27 22:38:50 2004 +0000
@@ -1,117 +1,87 @@
-/* -*- C++ -*-
- * src/lemon/list_graph.h - Part of LEMON, a generic C++ optimization library
- *
- * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
- * (Egervary Combinatorial Optimization Research Group, 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.
- *
- */
+// -*- c++ -*-
 
 #ifndef LEMON_LIST_GRAPH_H
 #define LEMON_LIST_GRAPH_H
 
-///\ingroup graphs
-///\file
-///\brief ListGraph, SymListGraph, NodeSet and EdgeSet classes.
+#include <lemon/erasable_graph_extender.h>
+#include <lemon/clearable_graph_extender.h>
+#include <lemon/extendable_graph_extender.h>
 
-#include <vector>
-#include <climits>
+#include <lemon/idmappable_graph_extender.h>
 
-#include <lemon/invalid.h>
+#include <lemon/iterable_graph_extender.h>
 
-#include <lemon/map_registry.h>
-#include <lemon/array_map.h>
+#include <lemon/alteration_observer_registry.h>
 
-#include <lemon/map_defines.h>
+#include <lemon/default_map.h>
 
 
 namespace lemon {
 
-/// \addtogroup graphs
-/// @{
+  class ListGraphBase {
 
-  ///A list graph class.
-
-  ///This is a simple and fast erasable graph implementation.
-  ///
-  ///It conforms to the
-  ///\ref skeleton::ErasableGraph "ErasableGraph" concept.
-  ///\sa skeleton::ErasableGraph.
-  class ListGraph {
-
-    //Nodes are double linked.
-    //The free nodes are only single linked using the "next" field.
-    struct NodeT 
-    {
+    struct NodeT {
       int first_in,first_out;
       int prev, next;
     };
-    //Edges are double linked.
-    //The free edges are only single linked using the "next_in" field.
-    struct EdgeT 
-    {
+ 
+    struct EdgeT {
       int head, tail;
       int prev_in, prev_out;
       int next_in, next_out;
     };
 
     std::vector<NodeT> nodes;
-    //The first node
+
     int first_node;
-    //The first free node
+
     int first_free_node;
+
     std::vector<EdgeT> edges;
-    //The first free edge
+
     int first_free_edge;
     
   public:
     
-    typedef ListGraph Graph;
+    typedef ListGraphBase Graph;
     
-    class Node;
-    class Edge;
+    class Node {
+      friend class Graph;
+    protected:
 
-    
-  public:
+      int id;
+      Node(int pid) { id = pid;}
 
-    class NodeIt;
-    class EdgeIt;
-    class OutEdgeIt;
-    class InEdgeIt;
+    public:
+      Node() {}
+      Node (Invalid) { id = -1; }
+      bool operator==(const Node& node) const {return id == node.id;}
+      bool operator!=(const Node& node) const {return id != node.id;}
+      bool operator<(const Node& node) const {return id < node.id;}
+    };
 
-    // Create map registries.
-    CREATE_MAP_REGISTRIES;
-    // Create node and edge maps.
-    CREATE_MAPS(ArrayMap);
+    class Edge {
+      friend class Graph;
+    protected:
 
-  public:
+      int id;
+      Edge(int pid) { id = pid;}
 
-    ListGraph() 
+    public:
+      Edge() {}
+      Edge (Invalid) { id = -1; }
+      bool operator==(const Edge& edge) const {return id == edge.id;}
+      bool operator!=(const Edge& edge) const {return id != edge.id;}
+      bool operator<(const Edge& edge) const {return id < edge.id;}
+    };
+
+
+
+    ListGraphBase()
       : nodes(), first_node(-1),
 	first_free_node(-1), edges(), first_free_edge(-1) {}
 
-    ListGraph(const ListGraph &_g) 
-      : nodes(_g.nodes), first_node(_g.first_node),
-	first_free_node(_g.first_free_node), edges(_g.edges),
-	first_free_edge(_g.first_free_edge) {}
     
-    /// \bug In the vector can be hole if a node is erased from the graph.
-    ///Number of nodes.
-    int nodeNum() const { return nodes.size(); }
-    ///Number of edges.
-    int edgeNum() const { return edges.size(); }
-
-    ///Set the expected maximum number of edges.
-
-    ///With this function, it is possible to set the expected number of edges.
-    ///The use of this fasten the building of the graph and makes
     ///it possible to avoid the superfluous memory allocation.
     void reserveEdge(int n) { edges.reserve(n); };
     
@@ -120,56 +90,75 @@
     /// Maximum node ID.
     ///\sa id(Node)
     int maxNodeId() const { return nodes.size()-1; } 
+
     /// Maximum edge ID.
     
     /// Maximum edge ID.
     ///\sa id(Edge)
     int maxEdgeId() const { return edges.size()-1; }
 
-    Node tail(Edge e) const { return edges[e.n].tail; }
-    Node head(Edge e) const { return edges[e.n].head; }
+    Node tail(Edge e) const { return edges[e.id].tail; }
+    Node head(Edge e) const { return edges[e.id].head; }
 
-    NodeIt& first(NodeIt& v) const { 
-      v=NodeIt(*this); return v; }
-    EdgeIt& first(EdgeIt& e) const { 
-      e=EdgeIt(*this); return e; }
-    OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
-      e=OutEdgeIt(*this,v); return e; }
-    InEdgeIt& first(InEdgeIt& e, const Node v) const { 
-      e=InEdgeIt(*this,v); return e; }
 
-    /// Node ID.
+    void first(Node& node) const { 
+      node.id = first_node;
+    }
+
+    void next(Node& node) const {
+      node.id = nodes[node.id].next;
+    }
+
+
+    void first(Edge& e) const { 
+      int n;
+      for(n = first_node; 
+	  n!=-1 && nodes[n].first_in == -1; 
+	  n = nodes[n].next);
+      e.id = (n == -1) ? -1 : nodes[n].first_in;
+    }
+
+    void next(Edge& edge) const {
+      if (edges[edge.id].next_in != -1) {
+	edge.id = edges[edge.id].next_in;
+      } else {
+	int n;
+	for(n = nodes[edges[edge.id].head].next;
+	  n!=-1 && nodes[n].first_in == -1; 
+	  n = nodes[n].next);
+	edge.id = (n == -1) ? -1 : nodes[n].first_in;
+      }      
+    }
+
+    void firstOut(Edge &e, const Node& v) const {
+      e.id = nodes[v.id].first_out;
+    }
+    void nextOut(Edge &e) const {
+      e.id=edges[e.id].next_out;
+    }
+
+    void firstIn(Edge &e, const Node& v) const {
+      e.id = nodes[v.id].first_in;
+    }
+    void nextIn(Edge &e) const {
+      e.id=edges[e.id].next_in;
+    }
+
     
-    /// The ID of a valid Node is a nonnegative integer not greater than
-    /// \ref maxNodeId(). The range of the ID's is not surely continuous
-    /// and the greatest node ID can be actually less then \ref maxNodeId().
-    ///
-    /// The ID of the \ref INVALID node is -1.
-    ///\return The ID of the node \c v. 
-    static int id(Node v) { return v.n; }
-    /// Edge ID.
-    
-    /// The ID of a valid Edge is a nonnegative integer not greater than
-    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
-    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
-    ///
-    /// The ID of the \ref INVALID edge is -1.
-    ///\return The ID of the edge \c e. 
-    static int id(Edge e) { return e.n; }
+    static int id(Node v) { return v.id; }
+    static int id(Edge e) { return e.id; }
 
     /// Adds a new node to the graph.
 
     /// \warning It adds the new node to the front of the list.
     /// (i.e. the lastly added node becomes the first.)
-    Node addNode() {
+    Node addNode() {     
       int n;
       
-      if(first_free_node==-1)
-	{
-	  n = nodes.size();
-	  nodes.push_back(NodeT());
-	}
-      else {
+      if(first_free_node==-1) {
+	n = nodes.size();
+	nodes.push_back(NodeT());
+      } else {
 	n = first_free_node;
 	first_free_node = nodes[n].next;
       }
@@ -181,1319 +170,108 @@
       
       nodes[n].first_in = nodes[n].first_out = -1;
       
-      Node nn; nn.n=n;
-
-      //Update dynamic maps
-      node_maps.add(nn);
-
-      return nn;
+      return Node(n);
     }
     
     Edge addEdge(Node u, Node v) {
-      int n;
-      
-      if(first_free_edge==-1)
-	{
-	  n = edges.size();
-	  edges.push_back(EdgeT());
-	}
-      else {
+      int n;      
+
+      if (first_free_edge == -1) {
+	n = edges.size();
+	edges.push_back(EdgeT());
+      } else {
 	n = first_free_edge;
 	first_free_edge = edges[n].next_in;
       }
       
-      edges[n].tail = u.n; edges[n].head = v.n;
+      edges[n].tail = u.id; 
+      edges[n].head = v.id;
 
-      edges[n].next_out = nodes[u.n].first_out;
-      if(nodes[u.n].first_out != -1) edges[nodes[u.n].first_out].prev_out = n;
-      edges[n].next_in = nodes[v.n].first_in;
-      if(nodes[v.n].first_in != -1) edges[nodes[v.n].first_in].prev_in = n;
+      edges[n].next_out = nodes[u.id].first_out;
+      if(nodes[u.id].first_out != -1) {
+	edges[nodes[u.id].first_out].prev_out = n;
+      }
+      
+      edges[n].next_in = nodes[v.id].first_in;
+      if(nodes[v.id].first_in != -1) {
+	edges[nodes[v.id].first_in].prev_in = n;
+      }
+      
       edges[n].prev_in = edges[n].prev_out = -1;
 	
-      nodes[u.n].first_out = nodes[v.n].first_in = n;
+      nodes[u.id].first_out = nodes[v.id].first_in = n;
 
-      Edge e; e.n=n;
-
-      //Update dynamic maps
-      edge_maps.add(e);
-
-      return e;
+      return Edge(n);
     }
     
-    /// Finds an edge between two nodes.
+    void erase(const Node& node) {
+      int n = node.id;
+      
+      if(nodes[n].next != -1) {
+	nodes[nodes[n].next].prev = nodes[n].prev;
+      }
+      
+      if(nodes[n].prev != -1) {
+	nodes[nodes[n].prev].next = nodes[n].next;
+      } else {
+	first_node = nodes[n].next;
+      }
+      
+      nodes[n].next = first_free_node;
+      first_free_node = n;
 
-    /// Finds an edge from node \c u to node \c v.
-    ///
-    /// If \c prev is \ref INVALID (this is the default value), then
-    /// It finds the first edge from \c u to \c v. Otherwise it looks for
-    /// the next edge from \c u to \c v after \c prev.
-    /// \return The found edge or INVALID if there is no such an edge.
-    Edge findEdge(Node u,Node v, Edge prev = INVALID) 
-    {
-      int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out;
-      while(e!=-1 && edges[e].tail!=v.n) e = edges[e].next_out;
-      prev.n=e;
-      return prev;
     }
     
-  private:
-    void eraseEdge(int n) {
+    void erase(const Edge& edge) {
+      int n = edge.id;
       
-      if(edges[n].next_in!=-1)
+      if(edges[n].next_in!=-1) {
 	edges[edges[n].next_in].prev_in = edges[n].prev_in;
-      if(edges[n].prev_in!=-1)
+      }
+
+      if(edges[n].prev_in!=-1) {
 	edges[edges[n].prev_in].next_in = edges[n].next_in;
-      else nodes[edges[n].head].first_in = edges[n].next_in;
+      } else {
+	nodes[edges[n].head].first_in = edges[n].next_in;
+      }
+
       
-      if(edges[n].next_out!=-1)
+      if(edges[n].next_out!=-1) {
 	edges[edges[n].next_out].prev_out = edges[n].prev_out;
-      if(edges[n].prev_out!=-1)
+      } 
+
+      if(edges[n].prev_out!=-1) {
 	edges[edges[n].prev_out].next_out = edges[n].next_out;
-      else nodes[edges[n].tail].first_out = edges[n].next_out;
+      } else {
+	nodes[edges[n].tail].first_out = edges[n].next_out;
+      }
       
       edges[n].next_in = first_free_edge;
       first_free_edge = n;      
 
-      //Update dynamic maps
-      Edge e; e.n=n;
-      edge_maps.erase(e);
-
     }
-      
-  public:
-
-    void erase(Node nn) {
-      int n=nn.n;
-      
-      int m;
-      while((m=nodes[n].first_in)!=-1) eraseEdge(m);
-      while((m=nodes[n].first_out)!=-1) eraseEdge(m);
-
-      if(nodes[n].next != -1) nodes[nodes[n].next].prev = nodes[n].prev;
-      if(nodes[n].prev != -1) nodes[nodes[n].prev].next = nodes[n].next;
-      else first_node = nodes[n].next;
-      
-      nodes[n].next = first_free_node;
-      first_free_node = n;
-
-      //Update dynamic maps
-      node_maps.erase(nn);
-
-    }
-    
-    void erase(Edge e) { eraseEdge(e.n); }
 
     void clear() {
-      edge_maps.clear();
       edges.clear();
-      node_maps.clear();
       nodes.clear();
-      first_node=first_free_node=first_free_edge=-1;
-    }
-
-    class Node {
-      friend class ListGraph;
-      template <typename T> friend class NodeMap;
-       
-      friend class Edge;
-      friend class OutEdgeIt;
-      friend class InEdgeIt;
-      friend class SymEdge;
-
-    protected:
-      int n;
-      friend int ListGraph::id(Node v); 
-      Node(int nn) {n=nn;}
-    public:
-      Node() {}
-      Node (Invalid) { n=-1; }
-      bool operator==(const Node i) const {return n==i.n;}
-      bool operator!=(const Node i) const {return n!=i.n;}
-      bool operator<(const Node i) const {return n<i.n;}
-      //      ///Validity check
-      //      operator bool() { return n!=-1; }
-    };
-    
-    class NodeIt : public Node {
-      const ListGraph *G;
-      friend class ListGraph;
-    public:
-      NodeIt() : Node() { }
-      NodeIt(Invalid i) : Node(i) { }
-      NodeIt(const ListGraph& _G) : Node(_G.first_node), G(&_G) { }
-      NodeIt(const ListGraph& _G,Node n) : Node(n), G(&_G) { }
-      NodeIt &operator++() {
-	n=G->nodes[n].next; 
-	return *this; 
-      }
-      //      ///Validity check
-      //      operator bool() { return Node::operator bool(); }      
-    };
-
-    class Edge {
-      friend class ListGraph;
-      template <typename T> friend class EdgeMap;
-
-      friend class SymListGraph;
-      
-      friend class Node;
-      friend class NodeIt;
-    protected:
-      int n;
-      friend int ListGraph::id(Edge e);
-
-    public:
-      /// An Edge with id \c n.
-
-      /// \bug It should be
-      /// obtained by a member function of the Graph.
-      Edge(int nn) {n=nn;}
-
-      Edge() { }
-      Edge (Invalid) { n=-1; }
-      bool operator==(const Edge i) const {return n==i.n;}
-      bool operator!=(const Edge i) const {return n!=i.n;}
-      bool operator<(const Edge i) const {return n<i.n;}
-      //      ///Validity check
-      //      operator bool() { return n!=-1; }
-   };
-    
-    class EdgeIt : public Edge {
-      const ListGraph *G;
-      friend class ListGraph;
-    public:
-      EdgeIt(const ListGraph& _G) : Edge(), G(&_G) {
-      	int m;
-	for(m=_G.first_node;
-	    m!=-1 && _G.nodes[m].first_in == -1; m = _G.nodes[m].next);
-	n = (m==-1)?-1:_G.nodes[m].first_in;
-      }
-      EdgeIt (Invalid i) : Edge(i) { }
-      EdgeIt(const ListGraph& _G, Edge e) : Edge(e), G(&_G) { }
-      EdgeIt() : Edge() { }
-      EdgeIt &operator++() {
-	if(G->edges[n].next_in!=-1) n=G->edges[n].next_in;
-	else {
-	  int nn;
-	  for(nn=G->nodes[G->edges[n].head].next;
-	      nn!=-1 && G->nodes[nn].first_in == -1;
-	      nn = G->nodes[nn].next) ;
-	  n = (nn==-1)?-1:G->nodes[nn].first_in;
-	}
-	return *this;
-      }
-      //      ///Validity check
-      //      operator bool() { return Edge::operator bool(); }      
-    };
-    
-    class OutEdgeIt : public Edge {
-      const ListGraph *G;
-      friend class ListGraph;
-    public: 
-      OutEdgeIt() : Edge() { }
-      OutEdgeIt(const ListGraph& _G, Edge e) : Edge(e), G(&_G) { }
-      OutEdgeIt (Invalid i) : Edge(i) { }
-
-      OutEdgeIt(const ListGraph& _G,const Node v)
-	: Edge(_G.nodes[v.n].first_out), G(&_G) {}
-      OutEdgeIt &operator++() { n=G->edges[n].next_out; return *this; }
-      //      ///Validity check
-      //      operator bool() { return Edge::operator bool(); }      
-    };
-    
-    class InEdgeIt : public Edge {
-      const ListGraph *G;
-      friend class ListGraph;
-    public: 
-      InEdgeIt() : Edge() { }
-      InEdgeIt(const ListGraph& _G, Edge e) : Edge(e), G(&_G) { }
-      InEdgeIt (Invalid i) : Edge(i) { }
-      InEdgeIt(const ListGraph& _G,Node v)
-	: Edge(_G.nodes[v.n].first_in), G(&_G) { }
-      InEdgeIt &operator++() { n=G->edges[n].next_in; return *this; }
-      //      ///Validity check
-      //      operator bool() { return Edge::operator bool(); }      
-    };
-  };
-
-  ///Graph for bidirectional edges.
-
-  ///The purpose of this graph structure is to handle graphs
-  ///having bidirectional edges. Here the function \c addEdge(u,v) adds a pair
-  ///of oppositely directed edges.
-  ///There is a new edge map type called
-  ///\ref lemon::SymListGraph::SymEdgeMap "SymEdgeMap"
-  ///that complements this
-  ///feature by
-  ///storing shared values for the edge pairs. The usual
-  ///\ref lemon::skeleton::StaticGraph::EdgeMap "EdgeMap"
-  ///can be used
-  ///as well.
-  ///
-  ///The oppositely directed edge can also be obtained easily
-  ///using \ref lemon::SymListGraph::opposite() "opposite()" member function.
-  ///
-  ///Here erase(Edge) deletes a pair of edges.
-  ///
-  ///\todo this date structure need some reconsiderations. Maybe it
-  ///should be implemented independently from ListGraph.
-  /*  
-  class SymListGraph : public ListGraph
-  {
-  public:
-
-    typedef SymListGraph Graph;
-
-    // Create symmetric map registry.
-    CREATE_SYM_EDGE_MAP_REGISTRY;
-    // Create symmetric edge map.
-    CREATE_SYM_EDGE_MAP(ArrayMap);
-
-    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);
-      Edge f = ListGraph::addEdge(v,u);
-      sym_edge_maps.add(e);
-      sym_edge_maps.add(f);
-      
-      return e;
-    }
-
-    void erase(Node n) { ListGraph::erase(n);}
-    ///The oppositely directed edge.
-
-    ///Returns the oppositely directed
-    ///pair of the edge \c e.
-    static Edge opposite(Edge e)
-    {
-      Edge f;
-      f.n = e.n - 2*(e.n%2) + 1;
-      return f;
-    }
-    
-    ///Removes a pair of oppositely directed edges to the graph.
-    void erase(Edge e) {
-      Edge f = opposite(e);
-      sym_edge_maps.erase(e);
-      sym_edge_maps.erase(f);
-      ListGraph::erase(f);
-      ListGraph::erase(e);
-    }    
-    };*/
-
-  class SymListGraph : public ListGraph {
-    typedef ListGraph Parent;
-  public:
-
-    typedef SymListGraph Graph;
-
-    typedef ListGraph::Node Node;
-    typedef ListGraph::NodeIt NodeIt;
-
-    class SymEdge;
-    class SymEdgeIt;
-
-    class Edge;
-    class EdgeIt;
-    class OutEdgeIt;
-    class InEdgeIt;
-
-    template <typename Value>
-    class NodeMap : public Parent::NodeMap<Value> {      
-    public:
-      NodeMap(const SymListGraph& g) 
-	: SymListGraph::Parent::NodeMap<Value>(g) {}
-      NodeMap(const SymListGraph& g, Value v) 
-	: SymListGraph::Parent::NodeMap<Value>(g, v) {}
-      template<typename TT> 
-      NodeMap(const NodeMap<TT>& copy) 
-	: SymListGraph::Parent::NodeMap<Value>(copy) { }            
-    };
-
-    template <typename Value>
-    class SymEdgeMap : public Parent::EdgeMap<Value> {
-    public:
-      typedef SymEdge KeyType;
-
-      SymEdgeMap(const SymListGraph& g) 
-	: SymListGraph::Parent::EdgeMap<Value>(g) {}
-      SymEdgeMap(const SymListGraph& g, Value v) 
-	: SymListGraph::Parent::EdgeMap<Value>(g, v) {}
-      template<typename TT> 
-      SymEdgeMap(const SymEdgeMap<TT>& copy) 
-	: SymListGraph::Parent::EdgeMap<Value>(copy) { }
-      
-    };
-
-    // Create edge map registry.
-    CREATE_EDGE_MAP_REGISTRY;
-    // Create edge maps.
-    CREATE_EDGE_MAP(ArrayMap);
-
-    class Edge {
-      friend class SymListGraph;
-      friend class SymListGraph::EdgeIt;
-      friend class SymListGraph::OutEdgeIt;
-      friend class SymListGraph::InEdgeIt;
-      
-    protected:
-      int id;
-
-      Edge(int pid) { id = pid; }
-
-    public:
-      /// An Edge with id \c n.
-
-      Edge() { }
-      Edge (Invalid) { id = -1; }
-
-      operator SymEdge(){ return SymEdge(id >> 1);}
-      
-      bool operator==(const Edge i) const {return id == i.id;}
-      bool operator!=(const Edge i) const {return id != i.id;}
-      bool operator<(const Edge i) const {return id < i.id;}
-      //      ///Validity check
-      //      operator bool() { return n!=-1; }
-    };
-
-    class SymEdge : public ListGraph::Edge {
-      friend class SymListGraph;
-      friend class SymListGraph::Edge;
-      typedef ListGraph::Edge Parent;
-
-    protected:      
-      SymEdge(int pid) : Parent(pid) {}
-    public:
-
-      SymEdge() { }
-      SymEdge(const ListGraph::Edge& i) : Parent(i) {} 
-      SymEdge (Invalid) : Parent(INVALID) {}
-
-    };
-
-    class OutEdgeIt {
-      Parent::OutEdgeIt out;
-      Parent::InEdgeIt in;      
-    public: 
-      OutEdgeIt() {}
-      OutEdgeIt(const SymListGraph& g, Edge e) { 
-	if ((e.id & 1) == 0) {	
-	  out = Parent::OutEdgeIt(g, SymEdge(e));
-	  in = Parent::InEdgeIt(g, g.tail(e));
-	} else {
-	  out = Parent::OutEdgeIt(INVALID);
-	  in = Parent::InEdgeIt(g, SymEdge(e));
-	}
-      }
-      OutEdgeIt (Invalid i) : out(INVALID), in(INVALID) { }
-
-      OutEdgeIt(const SymListGraph& g, const Node v)
-	: out(g, v), in(g, v) {}
-      OutEdgeIt &operator++() { 
-	if (out != INVALID) {
-	  ++out;
-	} else {
-	  ++in;
-	}
-	return *this; 
-      }
-
-      operator Edge() const {
-	if (out == INVALID && in == INVALID) return INVALID;
-	return out != INVALID ? forward(out) : backward(in);
-      }
-
-      bool operator==(const Edge i) const {return Edge(*this) == i;}
-      bool operator!=(const Edge i) const {return Edge(*this) != i;}
-      bool operator<(const Edge i) const {return Edge(*this) < i;}
-    };
-
-    class InEdgeIt {
-      Parent::OutEdgeIt out;
-      Parent::InEdgeIt in;      
-    public: 
-      InEdgeIt() {}
-      InEdgeIt(const SymListGraph& g, Edge e) { 
-	if ((e.id & 1) == 0) {	
-	  out = Parent::OutEdgeIt(g, SymEdge(e));
-	  in = Parent::InEdgeIt(g, g.tail(e));
-	} else {
-	  out = Parent::OutEdgeIt(INVALID);
-	  in = Parent::InEdgeIt(g, SymEdge(e));
-	}
-      }
-      InEdgeIt (Invalid i) : out(INVALID), in(INVALID) { }
-
-      InEdgeIt(const SymListGraph& g, const Node v)
-	: out(g, v), in(g, v) {}
-
-      InEdgeIt &operator++() { 
-	if (out != INVALID) {
-	  ++out;
-	} else {
-	  ++in;
-	}
-	return *this; 
-      }
-
-      operator Edge() const {
-	if (out == INVALID && in == INVALID) return INVALID;
-	return out != INVALID ? backward(out) : forward(in);
-      }
-
-      bool operator==(const Edge i) const {return Edge(*this) == i;}
-      bool operator!=(const Edge i) const {return Edge(*this) != i;}
-      bool operator<(const Edge i) const {return Edge(*this) < i;}
-    };
-
-    class SymEdgeIt : public Parent::EdgeIt {
-
-    public:
-      SymEdgeIt() {}
-
-      SymEdgeIt(const SymListGraph& g) 
-	: SymListGraph::Parent::EdgeIt(g) {}
-
-      SymEdgeIt(const SymListGraph& g, SymEdge e) 
-	: SymListGraph::Parent::EdgeIt(g, e) {}
-
-      SymEdgeIt(Invalid i) 
-	: SymListGraph::Parent::EdgeIt(INVALID) {}
-
-      SymEdgeIt& operator++() {
-	SymListGraph::Parent::EdgeIt::operator++();
-	return *this;
-      }
-
-      operator SymEdge() const {
-	return SymEdge
-	  (static_cast<const SymListGraph::Parent::EdgeIt&>(*this));
-      }
-      bool operator==(const SymEdge i) const {return SymEdge(*this) == i;}
-      bool operator!=(const SymEdge i) const {return SymEdge(*this) != i;}
-      bool operator<(const SymEdge i) const {return SymEdge(*this) < i;}
-    };
-
-    class EdgeIt {
-      SymEdgeIt it;
-      bool fw;
-    public:
-      EdgeIt(const SymListGraph& g) : it(g), fw(true) {}
-      EdgeIt (Invalid i) : it(i) { }
-      EdgeIt(const SymListGraph& g, Edge e) 
-	: it(g, SymEdge(e)), fw(id(e) & 1 == 0) { }
-      EdgeIt() { }
-      EdgeIt& operator++() {
-	fw = !fw;
-	if (fw) ++it;
-	return *this;
-      }
-      operator Edge() const {
-	if (it == INVALID) return INVALID;
-	return fw ? forward(it) : backward(it);
-      }
-      bool operator==(const Edge i) const {return Edge(*this) == i;}
-      bool operator!=(const Edge i) const {return Edge(*this) != i;}
-      bool operator<(const Edge i) const {return Edge(*this) < i;}
-
-    };
-
-    ///Number of nodes.
-    int nodeNum() const { return Parent::nodeNum(); }
-    ///Number of edges.
-    int edgeNum() const { return 2*Parent::edgeNum(); }
-    ///Number of symmetric edges.
-    int symEdgeNum() const { return Parent::edgeNum(); }
-
-    ///Set the expected maximum number of edges.
-
-    ///With this function, it is possible to set the expected number of edges.
-    ///The use of this fasten the building of the graph and makes
-    ///it possible to avoid the superfluous memory allocation.
-    void reserveSymEdge(int n) { Parent::reserveEdge(n); };
-    
-    /// Maximum node ID.
-    
-    /// Maximum node ID.
-    ///\sa id(Node)
-    int maxNodeId() const { return Parent::maxNodeId(); } 
-    /// Maximum edge ID.
-    
-    /// Maximum edge ID.
-    ///\sa id(Edge)
-    int maxEdgeId() const { return 2*Parent::maxEdgeId(); }
-    /// Maximum symmetric edge ID.
-    
-    /// Maximum symmetric edge ID.
-    ///\sa id(SymEdge)
-    int maxSymEdgeId() const { return Parent::maxEdgeId(); }
-
-
-    Node tail(Edge e) const { 
-      return (e.id & 1) == 0 ? 
-	Parent::tail(SymEdge(e)) : Parent::head(SymEdge(e)); 
-    }
-
-    Node head(Edge e) const { 
-      return (e.id & 1) == 0 ? 
-	Parent::head(SymEdge(e)) : Parent::tail(SymEdge(e)); 
-    }
-
-    Node tail(SymEdge e) const { 
-      return Parent::tail(e); 
-    }
-
-    Node head(SymEdge e) const { 
-      return Parent::head(e); 
-    }
-
-    NodeIt& first(NodeIt& v) const { 
-      v=NodeIt(*this); return v; }
-    EdgeIt& first(EdgeIt& e) const { 
-      e=EdgeIt(*this); return e; }
-    SymEdgeIt& first(SymEdgeIt& e) const {
-      e=SymEdgeIt(*this); return e; }
-    OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
-      e=OutEdgeIt(*this,v); return e; }
-    InEdgeIt& first(InEdgeIt& e, const Node v) const { 
-      e=InEdgeIt(*this,v); return e; }
-
-    /// Node ID.
-    
-    /// The ID of a valid Node is a nonnegative integer not greater than
-    /// \ref maxNodeId(). The range of the ID's is not surely continuous
-    /// and the greatest node ID can be actually less then \ref maxNodeId().
-    ///
-    /// The ID of the \ref INVALID node is -1.
-    ///\return The ID of the node \c v. 
-    static int id(Node v) { return Parent::id(v); }
-    /// Edge ID.
-    
-    /// The ID of a valid Edge is a nonnegative integer not greater than
-    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
-    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
-    ///
-    /// The ID of the \ref INVALID edge is -1.
-    ///\return The ID of the edge \c e. 
-    static int id(Edge e) { return e.id; }
-
-    /// The ID of a valid SymEdge is a nonnegative integer not greater than
-    /// \ref maxSymEdgeId(). The range of the ID's is not surely continuous
-    /// and the greatest edge ID can be actually less then \ref maxSymEdgeId().
-    ///
-    /// The ID of the \ref INVALID symmetric edge is -1.
-    ///\return The ID of the edge \c e. 
-    static int id(SymEdge e) { return Parent::id(e); }
-
-    /// Adds a new node to the graph.
-
-    /// \warning It adds the new node to the front of the list.
-    /// (i.e. the lastly added node becomes the first.)
-    Node addNode() {
-      return Parent::addNode();
-    }
-    
-    SymEdge addEdge(Node u, Node v) {
-      SymEdge se = Parent::addEdge(u, v);
-      edge_maps.add(forward(se));
-      edge_maps.add(backward(se));
-      return se;
-    }
-    
-    /// Finds an edge between two nodes.
-
-    /// Finds an edge from node \c u to node \c v.
-    ///
-    /// If \c prev is \ref INVALID (this is the default value), then
-    /// It finds the first edge from \c u to \c v. Otherwise it looks for
-    /// the next edge from \c u to \c v after \c prev.
-    /// \return The found edge or INVALID if there is no such an edge.
-    Edge findEdge(Node u, Node v, Edge prev = INVALID) 
-    {     
-      if (prev == INVALID || id(prev) & 1 == 0) {
-	SymEdge se = Parent::findEdge(u, v, SymEdge(prev));
-	if (se != INVALID) return forward(se);
-      } else {
-	SymEdge se = Parent::findEdge(v, u, SymEdge(prev));
-	if (se != INVALID) return backward(se);	
-      }
-      return INVALID;
-    }
-
-//     /// Finds an symmetric edge between two nodes.
-
-//     /// Finds an symmetric edge from node \c u to node \c v.
-//     ///
-//     /// If \c prev is \ref INVALID (this is the default value), then
-//     /// It finds the first edge from \c u to \c v. Otherwise it looks for
-//     /// the next edge from \c u to \c v after \c prev.
-//     /// \return The found edge or INVALID if there is no such an edge.
-
-//     SymEdge findEdge(Node u, Node v, SymEdge prev = INVALID) 
-//     {     
-//       if (prev == INVALID || id(prev) & 1 == 0) {
-// 	SymEdge se = Parent::findEdge(u, v, SymEdge(prev));
-// 	if (se != INVALID) return se;
-//       } else {
-// 	SymEdge se = Parent::findEdge(v, u, SymEdge(prev));
-// 	if (se != INVALID) return se;	
-//       }
-//       return INVALID;
-//     }
-    
-  public:
-
-    void erase(Node n) {      
-      for (OutEdgeIt it(*this, n); it != INVALID; ++it) {
-	edge_maps.erase(it);
-	edge_maps.erase(opposite(it));
-      }
-      Parent::erase(n);
-    }
-    
-    void erase(SymEdge e) { 
-      edge_maps.erase(forward(e));
-      edge_maps.erase(backward(e));
-      Parent::erase(e); 
-    };
-
-    void clear() {
-      edge_maps.clear();
-      Parent::clear();
-    }
-
-    static Edge opposite(Edge e) {
-      return Edge(id(e) ^ 1);
-    }
-
-    static Edge forward(SymEdge e) {
-      return Edge(id(e) << 1);
-    }
-
-    static Edge backward(SymEdge e) {
-      return Edge((id(e) << 1) | 1);
+      first_node = first_free_node = first_free_edge = -1;
     }
 
   };
 
-  ///A graph class containing only nodes.
+  typedef AlterableGraphExtender<ListGraphBase> AlterableListGraphBase;
+  typedef IterableGraphExtender<AlterableListGraphBase> IterableListGraphBase;
+  typedef IdMappableGraphExtender<IterableListGraphBase> IdMappableListGraphBase;
+  typedef DefaultMappableGraphExtender<IdMappableListGraphBase> MappableListGraphBase;
+  typedef ExtendableGraphExtender<MappableListGraphBase> ExtendableListGraphBase;
+  typedef ClearableGraphExtender<ExtendableListGraphBase> ClearableListGraphBase;
+  typedef ErasableGraphExtender<ClearableListGraphBase> ErasableListGraphBase;
 
-  ///This class implements a graph structure without edges.
-  ///The most useful application of this class is to be the node set of an
-  ///\ref EdgeSet class.
-  ///
-  ///It conforms to 
-  ///the \ref skeleton::ExtendableGraph "ExtendableGraph" concept
-  ///with the exception that you cannot
-  ///add (or delete) edges. The usual edge iterators are exists, but they are
-  ///always \ref INVALID.
-  ///\sa skeleton::ExtendableGraph
-  ///\sa EdgeSet
-  class NodeSet {
+  typedef ErasableListGraphBase ListGraph;
 
-    //Nodes are double linked.
-    //The free nodes are only single linked using the "next" field.
-    struct NodeT 
-    {
-      int first_in,first_out;
-      int prev, next;
-      //      NodeT() {}
-    };
+}
 
-    std::vector<NodeT> nodes;
-    //The first node
-    int first_node;
-    //The first free node
-    int first_free_node;
-    
-  public:
 
-    typedef NodeSet Graph;
-    
-    class Node;
-    class Edge;
+  
 
-  public:
-
-    class NodeIt;
-    class EdgeIt;
-    class OutEdgeIt;
-    class InEdgeIt;
-    
-    // Create node map registry.
-    CREATE_NODE_MAP_REGISTRY;
-    // Create node maps.
-    CREATE_NODE_MAP(ArrayMap);
-
-    /// Creating empty map structure for edges.
-    template <typename Value>
-    class EdgeMap {
-    public:
-      EdgeMap(const Graph&) {}
-      EdgeMap(const Graph&, const Value&) {}
-
-      EdgeMap(const EdgeMap&) {}
-      template <typename CMap> EdgeMap(const CMap&) {}
-
-      EdgeMap& operator=(const EdgeMap&) {}
-      template <typename CMap> EdgeMap& operator=(const CMap&) {}
-      
-      class ConstIterator {
-      public:
-	bool operator==(const ConstIterator&) {return true;}
-	bool operator!=(const ConstIterator&) {return false;}
-      };
-
-      typedef ConstIterator Iterator;
-      
-      Iterator begin() { return Iterator();}
-      Iterator end() { return Iterator();}
-
-      ConstIterator begin() const { return ConstIterator();}
-      ConstIterator end() const { return ConstIterator();}
-
-    };
-    
-  public:
-
-    ///Default constructor
-    NodeSet() 
-      : nodes(), first_node(-1), first_free_node(-1) {}
-    ///Copy constructor
-    NodeSet(const NodeSet &_g) 
-      : nodes(_g.nodes), first_node(_g.first_node),
-	first_free_node(_g.first_free_node) {}
-    
-    ///Number of nodes.
-    int nodeNum() const { return nodes.size(); }
-    ///Number of edges.
-    int edgeNum() const { return 0; }
-
-    /// Maximum node ID.
-    
-    /// Maximum node ID.
-    ///\sa id(Node)
-    int maxNodeId() const { return nodes.size()-1; }
-    /// Maximum edge ID.
-    
-    /// Maximum edge ID.
-    ///\sa id(Edge)
-    int maxEdgeId() const { return 0; }
-
-    Node tail(Edge e) const { return INVALID; }
-    Node head(Edge e) const { return INVALID; }
-
-    NodeIt& first(NodeIt& v) const { 
-      v=NodeIt(*this); return v; }
-    EdgeIt& first(EdgeIt& e) const { 
-      e=EdgeIt(*this); return e; }
-    OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
-      e=OutEdgeIt(*this,v); return e; }
-    InEdgeIt& first(InEdgeIt& e, const Node v) const { 
-      e=InEdgeIt(*this,v); return e; }
-
-    /// Node ID.
-    
-    /// The ID of a valid Node is a nonnegative integer not greater than
-    /// \ref maxNodeId(). The range of the ID's is not surely continuous
-    /// and the greatest node ID can be actually less then \ref maxNodeId().
-    ///
-    /// The ID of the \ref INVALID node is -1.
-    ///\return The ID of the node \c v. 
-    static int id(Node v) { return v.n; }
-    /// Edge ID.
-    
-    /// The ID of a valid Edge is a nonnegative integer not greater than
-    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
-    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
-    ///
-    /// The ID of the \ref INVALID edge is -1.
-    ///\return The ID of the edge \c e. 
-    static int id(Edge e) { return -1; }
-
-    /// Adds a new node to the graph.
-
-    /// \warning It adds the new node to the front of the list.
-    /// (i.e. the lastly added node becomes the first.)
-    Node addNode() {
-      int n;
-      
-      if(first_free_node==-1)
-	{
-	  n = nodes.size();
-	  nodes.push_back(NodeT());
-	}
-      else {
-	n = first_free_node;
-	first_free_node = nodes[n].next;
-      }
-      
-      nodes[n].next = first_node;
-      if(first_node != -1) nodes[first_node].prev = n;
-      first_node = n;
-      nodes[n].prev = -1;
-      
-      nodes[n].first_in = nodes[n].first_out = -1;
-      
-      Node nn; nn.n=n;
-
-      //Update dynamic maps
-      node_maps.add(nn);
-
-      return nn;
-    }
-    
-    void erase(Node nn) {
-      int n=nn.n;
-      
-      if(nodes[n].next != -1) nodes[nodes[n].next].prev = nodes[n].prev;
-      if(nodes[n].prev != -1) nodes[nodes[n].prev].next = nodes[n].next;
-      else first_node = nodes[n].next;
-      
-      nodes[n].next = first_free_node;
-      first_free_node = n;
-
-      //Update dynamic maps
-      node_maps.erase(nn);
-    }
-    
-        
-    Edge findEdge(Node u,Node v, Edge prev = INVALID) 
-    {
-      return INVALID;
-    }
-    
-    void clear() {
-      node_maps.clear();
-      nodes.clear();
-      first_node = first_free_node = -1;
-    }
-
-    class Node {
-      friend class NodeSet;
-      template <typename T> friend class NodeMap;
-      
-      friend class Edge;
-      friend class OutEdgeIt;
-      friend class InEdgeIt;
-
-    protected:
-      int n;
-      friend int NodeSet::id(Node v); 
-      Node(int nn) {n=nn;}
-    public:
-      Node() {}
-      Node (Invalid i) { n=-1; }
-      bool operator==(const Node i) const {return n==i.n;}
-      bool operator!=(const Node i) const {return n!=i.n;}
-      bool operator<(const Node i) const {return n<i.n;}
-    };
-    
-    class NodeIt : public Node {
-      const NodeSet *G;
-      friend class NodeSet;
-    public:
-      NodeIt() : Node() { }
-      NodeIt(const NodeSet& _G,Node n) : Node(n), G(&_G) { }
-      NodeIt(Invalid i) : Node(i) { }
-      NodeIt(const NodeSet& _G) : Node(_G.first_node), G(&_G) { }
-      NodeIt &operator++() {
-	n=G->nodes[n].next; 
-	return *this; 
-      }
-    };
-
-    class Edge {
-    public:
-      Edge() { }
-      Edge (Invalid) { }
-      bool operator==(const Edge i) const {return true;}
-      bool operator!=(const Edge i) const {return false;}
-      bool operator<(const Edge i) const {return false;}
-    };
-    
-    class EdgeIt : public Edge {
-    public:
-      EdgeIt(const NodeSet& G) : Edge() { }
-      EdgeIt(const NodeSet&, Edge) : Edge() { }
-      EdgeIt (Invalid i) : Edge(i) { }
-      EdgeIt() : Edge() { }
-      EdgeIt operator++() { return INVALID; }
-    };
-    
-    class OutEdgeIt : public Edge {
-      friend class NodeSet;
-    public: 
-      OutEdgeIt() : Edge() { }
-      OutEdgeIt(const NodeSet&, Edge) : Edge() { }
-      OutEdgeIt (Invalid i) : Edge(i) { }
-      OutEdgeIt(const NodeSet& G,const Node v)	: Edge() {}
-      OutEdgeIt operator++() { return INVALID; }
-    };
-    
-    class InEdgeIt : public Edge {
-      friend class NodeSet;
-    public: 
-      InEdgeIt() : Edge() { }
-      InEdgeIt(const NodeSet&, Edge) : Edge() { }
-      InEdgeIt (Invalid i) : Edge(i) { }
-      InEdgeIt(const NodeSet& G,Node v) :Edge() {}
-      InEdgeIt operator++() { return INVALID; }
-    };
-
-  };
-
-
-
-  ///Graph structure using a node set of another graph.
-
-  ///This structure can be used to establish another graph over a node set
-  /// of an existing one. The node iterator will go through the nodes of the
-  /// original graph, and the NodeMap's of both graphs will convert to
-  /// each other.
-  ///
-  ///\warning Adding or deleting nodes from the graph is not safe if an
-  ///\ref EdgeSet is currently attached to it!
-  ///
-  ///\todo Make it possible to add/delete edges from the base graph
-  ///(and from \ref EdgeSet, as well)
-  ///
-  ///\param GG The type of the graph which shares its node set with this class.
-  ///Its interface must conform to the
-  ///\ref skeleton::StaticGraph "StaticGraph" concept.
-  ///
-  ///It conforms to the 
-  ///\ref skeleton::ExtendableGraph "ExtendableGraph" concept.
-  ///\sa skeleton::ExtendableGraph.
-  ///\sa NodeSet.
-  template<typename GG>
-  class EdgeSet {
-
-    typedef GG NodeGraphType;
-
-    NodeGraphType &G;
-
-  public:
-
-    class Node;
-    class Edge;
-    class OutEdgeIt;
-    class InEdgeIt;
-    class SymEdge;
-
-    typedef EdgeSet Graph;
-
-    int id(Node v) const; 
-
-    class Node : public NodeGraphType::Node {
-      friend class EdgeSet;
-      
-      friend class Edge;
-      friend class OutEdgeIt;
-      friend class InEdgeIt;
-      friend class SymEdge;
-
-    public:
-      friend int EdgeSet::id(Node v) const; 
-    public:
-      Node() : NodeGraphType::Node() {}
-      Node (Invalid i) : NodeGraphType::Node(i) {}
-      Node(const typename NodeGraphType::Node &n) : NodeGraphType::Node(n) {}
-    };
-    
-    class NodeIt : public NodeGraphType::NodeIt {
-      friend class EdgeSet;
-    public:
-      NodeIt() : NodeGraphType::NodeIt() { }
-      NodeIt(const EdgeSet& _G,Node n) : NodeGraphType::NodeIt(_G.G,n) { }
-      NodeIt (Invalid i) : NodeGraphType::NodeIt(i) {}
-      NodeIt(const EdgeSet& _G) : NodeGraphType::NodeIt(_G.G) { }
-      NodeIt(const typename NodeGraphType::NodeIt &n)
-	: NodeGraphType::NodeIt(n) {}
-
-      operator Node() { return Node(*this);}
-      NodeIt &operator++()
-      { this->NodeGraphType::NodeIt::operator++(); return *this;} 
-    };
-
-  private:
-    //Edges are double linked.
-    //The free edges are only single linked using the "next_in" field.
-    struct NodeT 
-    {
-      int first_in,first_out;
-      NodeT() : first_in(-1), first_out(-1) { }
-    };
-
-    struct EdgeT 
-    {
-      Node head, tail;
-      int prev_in, prev_out;
-      int next_in, next_out;
-    };
-
-    
-    typename NodeGraphType::template NodeMap<NodeT> nodes;
-    
-    std::vector<EdgeT> edges;
-    //The first free edge
-    int first_free_edge;
-    
-  public:
-    
-    class Node;
-    class Edge;
-
-    class NodeIt;
-    class EdgeIt;
-    class OutEdgeIt;
-    class InEdgeIt;
-
-
-    // Create edge map registry.
-    CREATE_EDGE_MAP_REGISTRY;
-    // Create edge maps.
-    CREATE_EDGE_MAP(ArrayMap);
-
-    // Import node maps from the NodeGraphType.
-    IMPORT_NODE_MAP(NodeGraphType, graph.G, EdgeSet, graph);
-    
-    
-  public:
-
-    ///Constructor
-    
-    ///Construates a new graph based on the nodeset of an existing one.
-    ///\param _G the base graph.
-    explicit EdgeSet(NodeGraphType &_G) 
-      : G(_G), nodes(_G), edges(),
-	first_free_edge(-1) {}
-    ///Copy constructor
-
-    ///Makes a copy of an EdgeSet.
-    ///It will be based on the same graph.
-    explicit EdgeSet(const EdgeSet &_g) 
-      : G(_g.G), nodes(_g.G), edges(_g.edges),
-	first_free_edge(_g.first_free_edge) {}
-    
-    ///Number of nodes.
-    int nodeNum() const { return G.nodeNum(); }
-    ///Number of edges.
-    int edgeNum() const { return edges.size(); }
-
-    /// Maximum node ID.
-    
-    /// Maximum node ID.
-    ///\sa id(Node)
-    int maxNodeId() const { return G.maxNodeId(); }
-    /// Maximum edge ID.
-    
-    /// Maximum edge ID.
-    ///\sa id(Edge)
-    int maxEdgeId() const { return edges.size()-1; }
-
-    Node tail(Edge e) const { return edges[e.n].tail; }
-    Node head(Edge e) const { return edges[e.n].head; }
-
-    NodeIt& first(NodeIt& v) const { 
-      v=NodeIt(*this); return v; }
-    EdgeIt& first(EdgeIt& e) const { 
-      e=EdgeIt(*this); return e; }
-    OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
-      e=OutEdgeIt(*this,v); return e; }
-    InEdgeIt& first(InEdgeIt& e, const Node v) const { 
-      e=InEdgeIt(*this,v); return e; }
-
-    /// Node ID.
-    
-    /// The ID of a valid Node is a nonnegative integer not greater than
-    /// \ref maxNodeId(). The range of the ID's is not surely continuous
-    /// and the greatest node ID can be actually less then \ref maxNodeId().
-    ///
-    /// The ID of the \ref INVALID node is -1.
-    ///\return The ID of the node \c v. 
-    int id(Node v) { return G.id(v); }
-    /// Edge ID.
-    
-    /// The ID of a valid Edge is a nonnegative integer not greater than
-    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
-    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
-    ///
-    /// The ID of the \ref INVALID edge is -1.
-    ///\return The ID of the edge \c e. 
-    static int id(Edge e) { return e.n; }
-
-    /// Adds a new node to the graph.
-    Node addNode() { return G.addNode(); }
-    
-    Edge addEdge(Node u, Node v) {
-      int n;
-      
-      if(first_free_edge==-1)
-	{
-	  n = edges.size();
-	  edges.push_back(EdgeT());
-	}
-      else {
-	n = first_free_edge;
-	first_free_edge = edges[n].next_in;
-      }
-      
-      edges[n].tail = u; edges[n].head = v;
-
-      edges[n].next_out = nodes[u].first_out;
-      if(nodes[u].first_out != -1) edges[nodes[u].first_out].prev_out = n;
-      edges[n].next_in = nodes[v].first_in;
-      if(nodes[v].first_in != -1) edges[nodes[v].first_in].prev_in = n;
-      edges[n].prev_in = edges[n].prev_out = -1;
-	
-      nodes[u].first_out = nodes[v].first_in = n;
-
-      Edge e; e.n=n;
-
-      //Update dynamic maps
-      edge_maps.add(e);
-
-      return e;
-    }
-
-    /// Finds an edge between two nodes.
-
-    /// Finds an edge from node \c u to node \c v.
-    ///
-    /// If \c prev is \ref INVALID (this is the default value), then
-    /// It finds the first edge from \c u to \c v. Otherwise it looks for
-    /// the next edge from \c u to \c v after \c prev.
-    /// \return The found edge or INVALID if there is no such an edge.
-    Edge findEdge(Node u,Node v, Edge prev = INVALID) 
-    {
-      int e = (prev.n==-1)? nodes[u].first_out : edges[prev.n].next_out;
-      while(e!=-1 && edges[e].tail!=v) e = edges[e].next_out;
-      prev.n=e;
-      return prev;
-    }
-    
-  private:
-    void eraseEdge(int n) {
-      
-      if(edges[n].next_in!=-1)
-	edges[edges[n].next_in].prev_in = edges[n].prev_in;
-      if(edges[n].prev_in!=-1)
-	edges[edges[n].prev_in].next_in = edges[n].next_in;
-      else nodes[edges[n].head].first_in = edges[n].next_in;
-      
-      if(edges[n].next_out!=-1)
-	edges[edges[n].next_out].prev_out = edges[n].prev_out;
-      if(edges[n].prev_out!=-1)
-	edges[edges[n].prev_out].next_out = edges[n].next_out;
-      else nodes[edges[n].tail].first_out = edges[n].next_out;
-      
-      edges[n].next_in = first_free_edge;
-      first_free_edge = -1;      
-
-      //Update dynamic maps
-      Edge e; e.n = n;
-      edge_maps.erase(e);
-    }
-      
-  public:
-
-    void erase(Edge e) { eraseEdge(e.n); }
-
-    ///Clear all edges. (Doesn't clear the nodes!)
-    void clear() {
-      edge_maps.clear();
-      edges.clear();
-      first_free_edge=-1;
-    }
-
-
-    class Edge {
-    public:
-      friend class EdgeSet;
-      template <typename T> friend class EdgeMap;
-
-      friend class Node;
-      friend class NodeIt;
-    protected:
-      int n;
-      friend int EdgeSet::id(Edge e) const;
-
-      Edge(int nn) {n=nn;}
-    public:
-      Edge() { }
-      Edge (Invalid) { n=-1; }
-      bool operator==(const Edge i) const {return n==i.n;}
-      bool operator!=(const Edge i) const {return n!=i.n;}
-      bool operator<(const Edge i) const {return n<i.n;}
-    };
-    
-    class EdgeIt : public Edge {
-      friend class EdgeSet;
-      template <typename T> friend class EdgeMap;
-    
-      const EdgeSet *G;
-    public:
-      EdgeIt(const EdgeSet& _G) : Edge(), G(&_G) {
-        NodeIt m;
-	for(G->first(m);
-	    m!=INVALID && G->nodes[m].first_in == -1;  ++m);
-	///\bug AJJAJ! This is a non sense!!!!!!!
-	this->n = m!=INVALID?-1:G->nodes[m].first_in;
-      }
-      EdgeIt(const EdgeSet& _G, Edge e) : Edge(e), G(&_G) { }
-      EdgeIt (Invalid i) : Edge(i) { }
-      EdgeIt() : Edge() { }
-      ///.
-      
-      ///\bug UNIMPLEMENTED!!!!!
-      //
-      EdgeIt &operator++() {
-	return *this;
-      }
-    };
-    
-    class OutEdgeIt : public Edge {
-      const EdgeSet *G;
-      friend class EdgeSet;
-    public: 
-      OutEdgeIt() : Edge() { }
-      OutEdgeIt (Invalid i) : Edge(i) { }
-      OutEdgeIt(const EdgeSet& _G, Edge e) : Edge(e), G(&_G) { }
-
-      OutEdgeIt(const EdgeSet& _G,const Node v) :
-	Edge(_G.nodes[v].first_out), G(&_G) { }
-      OutEdgeIt &operator++() { 
-	Edge::n = G->edges[Edge::n].next_out;
-	return *this; 
-      }
-    };
-    
-    class InEdgeIt : public Edge {
-      const EdgeSet *G;
-      friend class EdgeSet;
-    public: 
-      InEdgeIt() : Edge() { }
-      InEdgeIt (Invalid i) : Edge(i) { }
-      InEdgeIt(const EdgeSet& _G, Edge e) : Edge(e), G(&_G) { }
-      InEdgeIt(const EdgeSet& _G,Node v)
-	: Edge(_G.nodes[v].first_in), G(&_G) { }
-      InEdgeIt &operator++() { 
-	Edge::n = G->edges[Edge::n].next_in; 
-	return *this; 
-      }
-    };
-    
-  };
-
-  template<typename GG>
-  inline int EdgeSet<GG>::id(Node v) const { return G.id(v); }
-
-/// @}  
-
-} //namespace lemon
-
-#endif //LEMON_LIST_GRAPH_H
+#endif