src/hugo/list_graph.h
author marci
Wed, 12 May 2004 13:19:32 +0000
changeset 621 2db02d4a9e6e
parent 579 859f8c7e2a40
child 681 06a3cba90f94
permissions -rw-r--r--
BidirGraphWrapper<Graph> bug volt
     1 // -*- mode:C++ -*-
     2 
     3 #ifndef HUGO_LIST_GRAPH_H
     4 #define HUGO_LIST_GRAPH_H
     5 
     6 ///\ingroup graphs
     7 ///\file
     8 ///\brief ListGraph, SymListGraph, NodeSet and EdgeSet classes.
     9 
    10 #include <vector>
    11 #include <limits.h>
    12 
    13 #include <hugo/invalid.h>
    14 
    15 namespace hugo {
    16 
    17 /// \addtogroup graphs
    18 /// @{
    19 
    20   class SymListGraph;
    21 
    22   ///A list graph class.
    23 
    24   ///This is a simple and fast erasable graph implementation.
    25   ///
    26   ///It conforms to the graph interface documented under
    27   ///the description of \ref GraphSkeleton.
    28   ///\sa \ref GraphSkeleton.
    29   class ListGraph {
    30 
    31     //Nodes are double linked.
    32     //The free nodes are only single linked using the "next" field.
    33     struct NodeT 
    34     {
    35       int first_in,first_out;
    36       int prev, next;
    37       //      NodeT() {}
    38     };
    39     //Edges are double linked.
    40     //The free edges are only single linked using the "next_in" field.
    41     struct EdgeT 
    42     {
    43       int head, tail;
    44       int prev_in, prev_out;
    45       int next_in, next_out;
    46       //FIXME: is this necessary?
    47       //      EdgeT() : next_in(-1), next_out(-1) prev_in(-1), prev_out(-1) {}  
    48     };
    49 
    50     std::vector<NodeT> nodes;
    51     //The first node
    52     int first_node;
    53     //The first free node
    54     int first_free_node;
    55     std::vector<EdgeT> edges;
    56     //The first free edge
    57     int first_free_edge;
    58     
    59   protected:
    60     
    61     template <typename Key> class DynMapBase
    62     {
    63     protected:
    64       const ListGraph* G; 
    65     public:
    66       virtual void add(const Key k) = 0;
    67       virtual void erase(const Key k) = 0;
    68       DynMapBase(const ListGraph &_G) : G(&_G) {}
    69       virtual ~DynMapBase() {}
    70       friend class ListGraph;
    71     };
    72     
    73   public:
    74     template <typename T> class EdgeMap;
    75     template <typename T> class NodeMap;
    76     
    77     class Node;
    78     class Edge;
    79 
    80     //  protected:
    81     // HELPME:
    82   protected:
    83     ///\bug It must be public because of SymEdgeMap.
    84     ///
    85     mutable std::vector<DynMapBase<Node> * > dyn_node_maps;
    86     ///\bug It must be public because of SymEdgeMap.
    87     ///
    88     mutable std::vector<DynMapBase<Edge> * > dyn_edge_maps;
    89     
    90   public:
    91 
    92     class NodeIt;
    93     class EdgeIt;
    94     class OutEdgeIt;
    95     class InEdgeIt;
    96     
    97   public:
    98 
    99     ListGraph() : nodes(), first_node(-1),
   100 		  first_free_node(-1), edges(), first_free_edge(-1) {}
   101     ListGraph(const ListGraph &_g) : nodes(_g.nodes), first_node(_g.first_node),
   102 				     first_free_node(_g.first_free_node),
   103 				     edges(_g.edges),
   104 				     first_free_edge(_g.first_free_edge) {}
   105     
   106     ~ListGraph()
   107     {
   108       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   109 	  i!=dyn_node_maps.end(); ++i) (**i).G=NULL;
   110       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();
   111 	  i!=dyn_edge_maps.end(); ++i) (**i).G=NULL;
   112     }
   113 
   114     int nodeNum() const { return nodes.size(); }  //FIXME: What is this?
   115     int edgeNum() const { return edges.size(); }  //FIXME: What is this?
   116 
   117     ///\bug This function does something different than
   118     ///its name would suggests...
   119     int maxNodeId() const { return nodes.size(); }  //FIXME: What is this?
   120     ///\bug This function does something different than
   121     ///its name would suggests...
   122     int maxEdgeId() const { return edges.size(); }  //FIXME: What is this?
   123 
   124     Node tail(Edge e) const { return edges[e.n].tail; }
   125     Node head(Edge e) const { return edges[e.n].head; }
   126 
   127     Node aNode(OutEdgeIt e) const { return edges[e.n].tail; }
   128     Node aNode(InEdgeIt e) const { return edges[e.n].head; }
   129 
   130     Node bNode(OutEdgeIt e) const { return edges[e.n].head; }
   131     Node bNode(InEdgeIt e) const { return edges[e.n].tail; }
   132 
   133     NodeIt& first(NodeIt& v) const { 
   134       v=NodeIt(*this); return v; }
   135     EdgeIt& first(EdgeIt& e) const { 
   136       e=EdgeIt(*this); return e; }
   137     OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
   138       e=OutEdgeIt(*this,v); return e; }
   139     InEdgeIt& first(InEdgeIt& e, const Node v) const { 
   140       e=InEdgeIt(*this,v); return e; }
   141 
   142 //     template< typename It >
   143 //     It first() const { It e; first(e); return e; }
   144 
   145 //     template< typename It >
   146 //     It first(Node v) const { It e; first(e,v); return e; }
   147 
   148     bool valid(Edge e) const { return e.n!=-1; }
   149     bool valid(Node n) const { return n.n!=-1; }
   150     
   151     void setInvalid(Edge &e) { e.n=-1; }
   152     void setInvalid(Node &n) { n.n=-1; }
   153     
   154     template <typename It> It getNext(It it) const
   155     { It tmp(it); return next(tmp); }
   156 
   157     NodeIt& next(NodeIt& it) const { 
   158       it.n=nodes[it.n].next; 
   159       return it; 
   160     }
   161     OutEdgeIt& next(OutEdgeIt& it) const
   162     { it.n=edges[it.n].next_out; return it; }
   163     InEdgeIt& next(InEdgeIt& it) const
   164     { it.n=edges[it.n].next_in; return it; }
   165     EdgeIt& next(EdgeIt& it) const {
   166       if(edges[it.n].next_in!=-1) { 
   167 	it.n=edges[it.n].next_in;
   168       }
   169       else {
   170 	int n;
   171 	for(n=nodes[edges[it.n].head].next;
   172 	    n!=-1 && nodes[n].first_in == -1;
   173 	    n = nodes[n].next) ;
   174 	it.n = (n==-1)?-1:nodes[n].first_in;
   175       }
   176       return it;
   177     }
   178 
   179     int id(Node v) const { return v.n; }
   180     int id(Edge e) const { return e.n; }
   181 
   182     /// Adds a new node to the graph.
   183 
   184     /// \todo It adds the nodes in a reversed order.
   185     /// (i.e. the lastly added node becomes the first.)
   186     Node addNode() {
   187       int n;
   188       
   189       if(first_free_node==-1)
   190 	{
   191 	  n = nodes.size();
   192 	  nodes.push_back(NodeT());
   193 	}
   194       else {
   195 	n = first_free_node;
   196 	first_free_node = nodes[n].next;
   197       }
   198       
   199       nodes[n].next = first_node;
   200       if(first_node != -1) nodes[first_node].prev = n;
   201       first_node = n;
   202       nodes[n].prev = -1;
   203       
   204       nodes[n].first_in = nodes[n].first_out = -1;
   205       
   206       Node nn; nn.n=n;
   207 
   208       //Update dynamic maps
   209       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   210 	  i!=dyn_node_maps.end(); ++i) (**i).add(nn);
   211 
   212       return nn;
   213     }
   214     
   215     Edge addEdge(Node u, Node v) {
   216       int n;
   217       
   218       if(first_free_edge==-1)
   219 	{
   220 	  n = edges.size();
   221 	  edges.push_back(EdgeT());
   222 	}
   223       else {
   224 	n = first_free_edge;
   225 	first_free_edge = edges[n].next_in;
   226       }
   227       
   228       edges[n].tail = u.n; edges[n].head = v.n;
   229 
   230       edges[n].next_out = nodes[u.n].first_out;
   231       if(nodes[u.n].first_out != -1) edges[nodes[u.n].first_out].prev_out = n;
   232       edges[n].next_in = nodes[v.n].first_in;
   233       if(nodes[v.n].first_in != -1) edges[nodes[v.n].first_in].prev_in = n;
   234       edges[n].prev_in = edges[n].prev_out = -1;
   235 	
   236       nodes[u.n].first_out = nodes[v.n].first_in = n;
   237 
   238       Edge e; e.n=n;
   239 
   240       //Update dynamic maps
   241       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();
   242 	  i!=dyn_edge_maps.end(); ++i) (**i).add(e);
   243 
   244       return e;
   245     }
   246 
   247   private:
   248     void eraseEdge(int n) {
   249       
   250       if(edges[n].next_in!=-1)
   251 	edges[edges[n].next_in].prev_in = edges[n].prev_in;
   252       if(edges[n].prev_in!=-1)
   253 	edges[edges[n].prev_in].next_in = edges[n].next_in;
   254       else nodes[edges[n].head].first_in = edges[n].next_in;
   255       
   256       if(edges[n].next_out!=-1)
   257 	edges[edges[n].next_out].prev_out = edges[n].prev_out;
   258       if(edges[n].prev_out!=-1)
   259 	edges[edges[n].prev_out].next_out = edges[n].next_out;
   260       else nodes[edges[n].tail].first_out = edges[n].next_out;
   261       
   262       edges[n].next_in = first_free_edge;
   263       first_free_edge = -1;      
   264 
   265       //Update dynamic maps
   266       Edge e; e.n=n;
   267       for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();
   268 	  i!=dyn_edge_maps.end(); ++i) (**i).erase(e);
   269     }
   270       
   271   public:
   272 
   273     void erase(Node nn) {
   274       int n=nn.n;
   275       
   276       int m;
   277       while((m=nodes[n].first_in)!=-1) eraseEdge(m);
   278       while((m=nodes[n].first_out)!=-1) eraseEdge(m);
   279 
   280       if(nodes[n].next != -1) nodes[nodes[n].next].prev = nodes[n].prev;
   281       if(nodes[n].prev != -1) nodes[nodes[n].prev].next = nodes[n].next;
   282       else first_node = nodes[n].next;
   283       
   284       nodes[n].next = first_free_node;
   285       first_free_node = n;
   286 
   287       //Update dynamic maps
   288       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   289 	  i!=dyn_node_maps.end(); ++i) (**i).erase(nn);
   290     }
   291     
   292     void erase(Edge e) { eraseEdge(e.n); }
   293 
   294     ///\bug Dynamic maps must be updated!
   295     ///
   296     void clear() {
   297       nodes.clear();edges.clear();
   298       first_node=first_free_node=first_free_edge=-1;
   299     }
   300 
   301     class Node {
   302       friend class ListGraph;
   303       template <typename T> friend class NodeMap;
   304        
   305       friend class Edge;
   306       friend class OutEdgeIt;
   307       friend class InEdgeIt;
   308       friend class SymEdge;
   309 
   310     protected:
   311       int n;
   312       friend int ListGraph::id(Node v) const; 
   313       Node(int nn) {n=nn;}
   314     public:
   315       Node() {}
   316       Node (Invalid) { n=-1; }
   317       bool operator==(const Node i) const {return n==i.n;}
   318       bool operator!=(const Node i) const {return n!=i.n;}
   319       bool operator<(const Node i) const {return n<i.n;}
   320     };
   321     
   322     class NodeIt : public Node {
   323       friend class ListGraph;
   324     public:
   325       NodeIt() : Node() { }
   326       NodeIt(Invalid i) : Node(i) { }
   327       NodeIt(const ListGraph& G) : Node(G.first_node) { }
   328       ///\todo Undocumented conversion Node -\> NodeIt.
   329       NodeIt(const ListGraph& G, const Node &n) : Node(n) { }
   330     };
   331 
   332     class Edge {
   333       friend class ListGraph;
   334       template <typename T> friend class EdgeMap;
   335 
   336       //template <typename T> friend class SymListGraph::SymEdgeMap;      
   337       //friend Edge SymListGraph::opposite(Edge) const;
   338       
   339       friend class Node;
   340       friend class NodeIt;
   341     protected:
   342       int n;
   343       friend int ListGraph::id(Edge e) const;
   344 
   345       Edge(int nn) {n=nn;}
   346     public:
   347       Edge() { }
   348       Edge (Invalid) { n=-1; }
   349       bool operator==(const Edge i) const {return n==i.n;}
   350       bool operator!=(const Edge i) const {return n!=i.n;}
   351       bool operator<(const Edge i) const {return n<i.n;}
   352       ///\bug This is a workaround until somebody tells me how to
   353       ///make class \c SymListGraph::SymEdgeMap friend of Edge
   354       int &idref() {return n;}
   355       const int &idref() const {return n;}
   356     };
   357     
   358     class EdgeIt : public Edge {
   359       friend class ListGraph;
   360     public:
   361       EdgeIt(const ListGraph& G) : Edge() {
   362       	int m;
   363 	for(m=G.first_node;
   364 	    m!=-1 && G.nodes[m].first_in == -1; m = G.nodes[m].next);
   365 	n = (m==-1)?-1:G.nodes[m].first_in;
   366       }
   367       EdgeIt (Invalid i) : Edge(i) { }
   368       EdgeIt() : Edge() { }
   369       ///\bug This is a workaround until somebody tells me how to
   370       ///make class \c SymListGraph::SymEdgeMap friend of Edge
   371       int &idref() {return n;}
   372     };
   373     
   374     class OutEdgeIt : public Edge {
   375       friend class ListGraph;
   376     public: 
   377       OutEdgeIt() : Edge() { }
   378       OutEdgeIt (Invalid i) : Edge(i) { }
   379 
   380       OutEdgeIt(const ListGraph& G,const Node v)
   381 	: Edge(G.nodes[v.n].first_out) {}
   382     };
   383     
   384     class InEdgeIt : public Edge {
   385       friend class ListGraph;
   386     public: 
   387       InEdgeIt() : Edge() { }
   388       InEdgeIt (Invalid i) : Edge(i) { }
   389       InEdgeIt(const ListGraph& G,Node v) :Edge(G.nodes[v.n].first_in){}
   390     };
   391 
   392     template <typename T> class NodeMap : public DynMapBase<Node>
   393     {
   394       std::vector<T> container;
   395 
   396     public:
   397       typedef T ValueType;
   398       typedef Node KeyType;
   399 
   400       NodeMap(const ListGraph &_G) :
   401 	DynMapBase<Node>(_G), container(_G.maxNodeId())
   402       {
   403 	G->dyn_node_maps.push_back(this);
   404       }
   405       NodeMap(const ListGraph &_G,const T &t) :
   406 	DynMapBase<Node>(_G), container(_G.maxNodeId(),t)
   407       {
   408 	G->dyn_node_maps.push_back(this);
   409       }
   410       
   411       NodeMap(const NodeMap<T> &m) :
   412  	DynMapBase<Node>(*m.G), container(m.container)
   413       {
   414  	G->dyn_node_maps.push_back(this);
   415       }
   416 
   417       template<typename TT> friend class NodeMap;
   418  
   419       ///\todo It can copy between different types.
   420       ///
   421       template<typename TT> NodeMap(const NodeMap<TT> &m) :
   422 	DynMapBase<Node>(*m.G), container(m.container.size())
   423 
   424       {
   425 	G->dyn_node_maps.push_back(this);
   426 	typename std::vector<TT>::const_iterator i;
   427 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
   428 	    i!=m.container.end();
   429 	    i++)
   430 	  container.push_back(*i);
   431       }
   432       ~NodeMap()
   433       {
   434 	if(G) {
   435 	  std::vector<DynMapBase<Node>* >::iterator i;
   436 	  for(i=G->dyn_node_maps.begin();
   437 	      i!=G->dyn_node_maps.end() && *i!=this; ++i) ;
   438 	  //if(*i==this) G->dyn_node_maps.erase(i); //FIXME: Way too slow...
   439 	  //A better way to do that: (Is this really important?)
   440 	  if(*i==this) {
   441 	    *i=G->dyn_node_maps.back();
   442 	    G->dyn_node_maps.pop_back();
   443 	  }
   444 	}
   445       }
   446 
   447       void add(const Node k) 
   448       {
   449 	if(k.n>=int(container.size())) container.resize(k.n+1);
   450       }
   451 
   452       void erase(const Node) { }
   453       
   454       void set(Node n, T a) { container[n.n]=a; }
   455       //'T& operator[](Node n)' would be wrong here
   456       typename std::vector<T>::reference
   457       operator[](Node n) { return container[n.n]; }
   458       //'const T& operator[](Node n)' would be wrong here
   459       typename std::vector<T>::const_reference 
   460       operator[](Node n) const { return container[n.n]; }
   461 
   462       ///\warning There is no safety check at all!
   463       ///Using operator = between maps attached to different graph may
   464       ///cause serious problem.
   465       ///\todo Is this really so?
   466       ///\todo It can copy between different types.
   467       const NodeMap<T>& operator=(const NodeMap<T> &m)
   468       {
   469 	container = m.container;
   470 	return *this;
   471       }
   472       template<typename TT>
   473       const NodeMap<T>& operator=(const NodeMap<TT> &m)
   474       {
   475 	std::copy(m.container.begin(), m.container.end(), container.begin());
   476 	return *this;
   477       }
   478       
   479       void update() {}    //Useless for Dynamic Maps
   480       void update(T a) {}  //Useless for Dynamic Maps
   481     };
   482     
   483     template <typename T> class EdgeMap : public DynMapBase<Edge>
   484     {
   485     protected:
   486       std::vector<T> container;
   487 
   488     public:
   489       typedef T ValueType;
   490       typedef Edge KeyType;
   491 
   492       EdgeMap(const ListGraph &_G) :
   493 	DynMapBase<Edge>(_G), container(_G.maxEdgeId())
   494       {
   495 	//FIXME: What if there are empty Id's?
   496 	//FIXME: Can I use 'this' in a constructor?
   497 	G->dyn_edge_maps.push_back(this);
   498       }
   499       EdgeMap(const ListGraph &_G,const T &t) :
   500 	DynMapBase<Edge>(_G), container(_G.maxEdgeId(),t)
   501       {
   502 	G->dyn_edge_maps.push_back(this);
   503       } 
   504       EdgeMap(const EdgeMap<T> &m) :
   505  	DynMapBase<Edge>(*m.G), container(m.container)
   506       {
   507  	G->dyn_edge_maps.push_back(this);
   508       }
   509 
   510       template<typename TT> friend class EdgeMap;
   511 
   512       ///\todo It can copy between different types.
   513       ///
   514       template<typename TT> EdgeMap(const EdgeMap<TT> &m) :
   515 	DynMapBase<Edge>(*m.G), container(m.container.size())
   516       {
   517 	G->dyn_edge_maps.push_back(this);
   518 	typename std::vector<TT>::const_iterator i;
   519 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
   520 	    i!=m.container.end();
   521 	    i++)
   522 	  container.push_back(*i);
   523       }
   524       ~EdgeMap()
   525       {
   526 	if(G) {
   527 	  std::vector<DynMapBase<Edge>* >::iterator i;
   528 	  for(i=G->dyn_edge_maps.begin();
   529 	      i!=G->dyn_edge_maps.end() && *i!=this; ++i) ;
   530 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...
   531 	  //A better way to do that: (Is this really important?)
   532 	  if(*i==this) {
   533 	    *i=G->dyn_edge_maps.back();
   534 	    G->dyn_edge_maps.pop_back();
   535 	  }
   536 	}
   537       }
   538       
   539       void add(const Edge k) 
   540       {
   541 	if(k.n>=int(container.size())) container.resize(k.n+1);
   542       }
   543       void erase(const Edge) { }
   544       
   545       void set(Edge n, T a) { container[n.n]=a; }
   546       //T get(Edge n) const { return container[n.n]; }
   547       typename std::vector<T>::reference
   548       operator[](Edge n) { return container[n.n]; }
   549       typename std::vector<T>::const_reference
   550       operator[](Edge n) const { return container[n.n]; }
   551 
   552       ///\warning There is no safety check at all!
   553       ///Using operator = between maps attached to different graph may
   554       ///cause serious problem.
   555       ///\todo Is this really so?
   556       ///\todo It can copy between different types.
   557       const EdgeMap<T>& operator=(const EdgeMap<T> &m)
   558       {
   559 	container = m.container;
   560 	return *this;
   561       }
   562       template<typename TT>
   563       const EdgeMap<T>& operator=(const EdgeMap<TT> &m)
   564       {
   565 	std::copy(m.container.begin(), m.container.end(), container.begin());
   566 	return *this;
   567       }
   568       
   569       void update() {}    //Useless for DynMaps
   570       void update(T a) {}  //Useless for DynMaps
   571     };
   572 
   573   };
   574 
   575   ///Graph for bidirectional edges.
   576 
   577   ///The purpose of this graph structure is to handle graphs
   578   ///having bidirectional edges. Here the function \c addEdge(u,v) adds a pair
   579   ///of oppositely directed edges.
   580   ///There is a new edge map type called
   581   ///\ref SymListGraph::SymEdgeMap "SymEdgeMap"
   582   ///that complements this
   583   ///feature by
   584   ///storing shared values for the edge pairs. The usual
   585   ///\ref GraphSkeleton::EdgeMap "EdgeMap"
   586   ///can be used
   587   ///as well.
   588   ///
   589   ///The oppositely directed edge can also be obtained easily
   590   ///using \ref opposite.
   591   ///
   592   ///Here erase(Edge) deletes a pair of edges.
   593   ///
   594   ///\todo this date structure need some reconsiderations. Maybe it
   595   ///should be implemented independently from ListGraph.
   596 
   597   class SymListGraph : public ListGraph
   598   {
   599   public:
   600     template<typename T> class SymEdgeMap;
   601     template<typename T> friend class SymEdgeMap;
   602 
   603     SymListGraph() : ListGraph() { }
   604     SymListGraph(const ListGraph &_g) : ListGraph(_g) { }
   605     ///Adds a pair of oppositely directed edges to the graph.
   606     Edge addEdge(Node u, Node v)
   607     {
   608       Edge e = ListGraph::addEdge(u,v);
   609       ListGraph::addEdge(v,u);
   610       return e;
   611     }
   612 
   613     void erase(Node n) { ListGraph::erase(n); }
   614     ///The oppositely directed edge.
   615 
   616     ///Returns the oppositely directed
   617     ///pair of the edge \c e.
   618     Edge opposite(Edge e) const
   619     {
   620       Edge f;
   621       f.idref() = e.idref() - 2*(e.idref()%2) + 1;
   622       return f;
   623     }
   624     
   625     ///Removes a pair of oppositely directed edges to the graph.
   626     void erase(Edge e) {
   627       ListGraph::erase(opposite(e));
   628       ListGraph::erase(e);
   629     }
   630     
   631     ///Common data storage for the edge pairs.
   632 
   633     ///This map makes it possible to store data shared by the oppositely
   634     ///directed pairs of edges.
   635     template <typename T> class SymEdgeMap : public DynMapBase<Edge>
   636     {
   637       std::vector<T> container;
   638       
   639     public:
   640       typedef T ValueType;
   641       typedef Edge KeyType;
   642 
   643       SymEdgeMap(const SymListGraph &_G) :
   644 	DynMapBase<Edge>(_G), container(_G.maxEdgeId()/2)
   645       {
   646 	static_cast<const SymListGraph*>(G)->dyn_edge_maps.push_back(this);
   647       }
   648       SymEdgeMap(const SymListGraph &_G,const T &t) :
   649 	DynMapBase<Edge>(_G), container(_G.maxEdgeId()/2,t)
   650       {
   651 	G->dyn_edge_maps.push_back(this);
   652       }
   653 
   654       SymEdgeMap(const SymEdgeMap<T> &m) :
   655  	DynMapBase<SymEdge>(*m.G), container(m.container)
   656       {
   657  	G->dyn_node_maps.push_back(this);
   658       }
   659 
   660       //      template<typename TT> friend class SymEdgeMap;
   661 
   662       ///\todo It can copy between different types.
   663       ///
   664 
   665       template<typename TT> SymEdgeMap(const SymEdgeMap<TT> &m) :
   666 	DynMapBase<SymEdge>(*m.G), container(m.container.size())
   667       {
   668 	G->dyn_node_maps.push_back(this);
   669 	typename std::vector<TT>::const_iterator i;
   670 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
   671 	    i!=m.container.end();
   672 	    i++)
   673 	  container.push_back(*i);
   674       }
   675  
   676       ~SymEdgeMap()
   677       {
   678 	if(G) {
   679 	  std::vector<DynMapBase<Edge>* >::iterator i;
   680 	  for(i=static_cast<const SymListGraph*>(G)->dyn_edge_maps.begin();
   681 	      i!=static_cast<const SymListGraph*>(G)->dyn_edge_maps.end()
   682 		&& *i!=this; ++i) ;
   683 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...
   684 	  //A better way to do that: (Is this really important?)
   685 	  if(*i==this) {
   686 	    *i=static_cast<const SymListGraph*>(G)->dyn_edge_maps.back();
   687 	    static_cast<const SymListGraph*>(G)->dyn_edge_maps.pop_back();
   688 	  }
   689 	}
   690       }
   691       
   692       void add(const Edge k) 
   693       {
   694 	if(!k.idref()%2&&k.idref()/2>=int(container.size()))
   695 	  container.resize(k.idref()/2+1);
   696       }
   697       void erase(const Edge k) { }
   698       
   699       void set(Edge n, T a) { container[n.idref()/2]=a; }
   700       //T get(Edge n) const { return container[n.idref()/2]; }
   701       typename std::vector<T>::reference
   702       operator[](Edge n) { return container[n.idref()/2]; }
   703       typename std::vector<T>::const_reference
   704       operator[](Edge n) const { return container[n.idref()/2]; }
   705 
   706       ///\warning There is no safety check at all!
   707       ///Using operator = between maps attached to different graph may
   708       ///cause serious problem.
   709       ///\todo Is this really so?
   710       ///\todo It can copy between different types.
   711       const SymEdgeMap<T>& operator=(const SymEdgeMap<T> &m)
   712       {
   713 	container = m.container;
   714 	return *this;
   715       }
   716       template<typename TT>
   717       const SymEdgeMap<T>& operator=(const SymEdgeMap<TT> &m)
   718       {
   719 	std::copy(m.container.begin(), m.container.end(), container.begin());
   720 	return *this;
   721       }
   722       
   723       void update() {}    //Useless for DynMaps
   724       void update(T a) {}  //Useless for DynMaps
   725 
   726     };
   727 
   728   };
   729   
   730 
   731   ///A graph class containing only nodes.
   732 
   733   ///This class implements a graph structure without edges.
   734   ///The most useful application of this class is to be the node set of an
   735   ///\ref EdgeSet class.
   736   ///
   737   ///It conforms to the graph interface documented under
   738   ///the description of \ref GraphSkeleton with the exception that you cannot
   739   ///add (or delete) edges. The usual edge iterators are exists, but they are
   740   ///always \ref INVALID.
   741   ///\sa \ref GraphSkeleton
   742   ///\sa \ref EdgeSet
   743   class NodeSet {
   744 
   745     //Nodes are double linked.
   746     //The free nodes are only single linked using the "next" field.
   747     struct NodeT 
   748     {
   749       int first_in,first_out;
   750       int prev, next;
   751       //      NodeT() {}
   752     };
   753 
   754     std::vector<NodeT> nodes;
   755     //The first node
   756     int first_node;
   757     //The first free node
   758     int first_free_node;
   759     
   760   protected:
   761     
   762     template <typename Key> class DynMapBase
   763     {
   764     protected:
   765       const NodeSet* G; 
   766     public:
   767       virtual void add(const Key k) = 0;
   768       virtual void erase(const Key k) = 0;
   769       DynMapBase(const NodeSet &_G) : G(&_G) {}
   770       virtual ~DynMapBase() {}
   771       friend class NodeSet;
   772     };
   773     
   774   public:
   775     template <typename T> class EdgeMap;
   776     template <typename T> class NodeMap;
   777     
   778     class Node;
   779     class Edge;
   780 
   781     //  protected:
   782     // HELPME:
   783   protected:
   784     ///\bug It must be public because of SymEdgeMap.
   785     ///
   786     mutable std::vector<DynMapBase<Node> * > dyn_node_maps;
   787     //mutable std::vector<DynMapBase<Edge> * > dyn_edge_maps;
   788     
   789   public:
   790 
   791     class NodeIt;
   792     class EdgeIt;
   793     class OutEdgeIt;
   794     class InEdgeIt;
   795     
   796     template <typename T> class NodeMap;
   797     template <typename T> class EdgeMap;
   798     
   799   public:
   800 
   801     ///Default constructor
   802     NodeSet() : nodes(), first_node(-1),
   803 		  first_free_node(-1) {}
   804     ///Copy constructor
   805     NodeSet(const NodeSet &_g) : nodes(_g.nodes), first_node(_g.first_node),
   806 				     first_free_node(_g.first_free_node) {}
   807     
   808     ~NodeSet()
   809     {
   810       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   811 	  i!=dyn_node_maps.end(); ++i) (**i).G=NULL;
   812       //for(std::vector<DynMapBase<Edge> * >::iterator i=dyn_edge_maps.begin();
   813       //	  i!=dyn_edge_maps.end(); ++i) (**i).G=NULL;
   814     }
   815 
   816     int nodeNum() const { return nodes.size(); }  //FIXME: What is this?
   817     int edgeNum() const { return 0; }  //FIXME: What is this?
   818 
   819     ///\bug This function does something different than
   820     ///its name would suggests...
   821     int maxNodeId() const { return nodes.size(); }  //FIXME: What is this?
   822     ///\bug This function does something different than
   823     ///its name would suggests...
   824     int maxEdgeId() const { return 0; }  //FIXME: What is this?
   825 
   826     Node tail(Edge e) const { return INVALID; }
   827     Node head(Edge e) const { return INVALID; }
   828 
   829     Node aNode(OutEdgeIt e) const { return INVALID; }
   830     Node aNode(InEdgeIt e) const { return INVALID; }
   831 
   832     Node bNode(OutEdgeIt e) const { return INVALID; }
   833     Node bNode(InEdgeIt e) const { return INVALID; }
   834 
   835     NodeIt& first(NodeIt& v) const { 
   836       v=NodeIt(*this); return v; }
   837     EdgeIt& first(EdgeIt& e) const { 
   838       e=EdgeIt(*this); return e; }
   839     OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
   840       e=OutEdgeIt(*this,v); return e; }
   841     InEdgeIt& first(InEdgeIt& e, const Node v) const { 
   842       e=InEdgeIt(*this,v); return e; }
   843 
   844 //     template< typename It >
   845 //     It first() const { It e; first(e); return e; }
   846 
   847 //     template< typename It >
   848 //     It first(Node v) const { It e; first(e,v); return e; }
   849 
   850     bool valid(Edge e) const { return false; }
   851     bool valid(Node n) const { return n.n!=-1; }
   852     
   853     void setInvalid(Edge &e) { }
   854     void setInvalid(Node &n) { n.n=-1; }
   855     
   856     template <typename It> It getNext(It it) const
   857     { It tmp(it); return next(tmp); }
   858 
   859     NodeIt& next(NodeIt& it) const { 
   860       it.n=nodes[it.n].next; 
   861       return it; 
   862     }
   863     OutEdgeIt& next(OutEdgeIt& it) const { return it; }
   864     InEdgeIt& next(InEdgeIt& it) const { return it; }
   865     EdgeIt& next(EdgeIt& it) const { return it; }
   866 
   867     int id(Node v) const { return v.n; }
   868     int id(Edge e) const { return -1; }
   869 
   870     /// Adds a new node to the graph.
   871 
   872     /// \todo It adds the nodes in a reversed order.
   873     /// (i.e. the lastly added node becomes the first.)
   874     Node addNode() {
   875       int n;
   876       
   877       if(first_free_node==-1)
   878 	{
   879 	  n = nodes.size();
   880 	  nodes.push_back(NodeT());
   881 	}
   882       else {
   883 	n = first_free_node;
   884 	first_free_node = nodes[n].next;
   885       }
   886       
   887       nodes[n].next = first_node;
   888       if(first_node != -1) nodes[first_node].prev = n;
   889       first_node = n;
   890       nodes[n].prev = -1;
   891       
   892       nodes[n].first_in = nodes[n].first_out = -1;
   893       
   894       Node nn; nn.n=n;
   895 
   896       //Update dynamic maps
   897       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   898 	  i!=dyn_node_maps.end(); ++i) (**i).add(nn);
   899 
   900       return nn;
   901     }
   902     
   903     void erase(Node nn) {
   904       int n=nn.n;
   905       
   906       if(nodes[n].next != -1) nodes[nodes[n].next].prev = nodes[n].prev;
   907       if(nodes[n].prev != -1) nodes[nodes[n].prev].next = nodes[n].next;
   908       else first_node = nodes[n].next;
   909       
   910       nodes[n].next = first_free_node;
   911       first_free_node = n;
   912 
   913       //Update dynamic maps
   914       for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
   915 	  i!=dyn_node_maps.end(); ++i) (**i).erase(nn);
   916     }
   917     
   918     ///\bug Dynamic maps must be updated!
   919     ///
   920     void clear() {
   921       nodes.clear();
   922       first_node = first_free_node = -1;
   923     }
   924 
   925     class Node {
   926       friend class NodeSet;
   927       template <typename T> friend class NodeMap;
   928       
   929       friend class Edge;
   930       friend class OutEdgeIt;
   931       friend class InEdgeIt;
   932 
   933     protected:
   934       int n;
   935       friend int NodeSet::id(Node v) const; 
   936       Node(int nn) {n=nn;}
   937     public:
   938       Node() {}
   939       Node (Invalid i) { n=-1; }
   940       bool operator==(const Node i) const {return n==i.n;}
   941       bool operator!=(const Node i) const {return n!=i.n;}
   942       bool operator<(const Node i) const {return n<i.n;}
   943     };
   944     
   945     class NodeIt : public Node {
   946       friend class NodeSet;
   947     public:
   948       NodeIt() : Node() { }
   949       NodeIt(Invalid i) : Node(i) { }
   950       NodeIt(const NodeSet& G) : Node(G.first_node) { }
   951       ///\todo Undocumented conversion Node -\> NodeIt.
   952       NodeIt(const NodeSet& G, const Node &n) : Node(n) { }
   953 
   954     };
   955 
   956     class Edge {
   957       //friend class NodeSet;
   958       //template <typename T> friend class EdgeMap;
   959 
   960       //template <typename T> friend class SymNodeSet::SymEdgeMap;      
   961       //friend Edge SymNodeSet::opposite(Edge) const;
   962       
   963       //      friend class Node;
   964       //      friend class NodeIt;
   965     protected:
   966       //friend int NodeSet::id(Edge e) const;
   967       //      Edge(int nn) {}
   968     public:
   969       Edge() { }
   970       Edge (Invalid) { }
   971       bool operator==(const Edge i) const {return true;}
   972       bool operator!=(const Edge i) const {return false;}
   973       bool operator<(const Edge i) const {return false;}
   974       ///\bug This is a workaround until somebody tells me how to
   975       ///make class \c SymNodeSet::SymEdgeMap friend of Edge
   976       //      int idref() {return -1;}
   977       //      int idref() const {return -1;}
   978     };
   979     
   980     class EdgeIt : public Edge {
   981       //friend class NodeSet;
   982     public:
   983       EdgeIt(const NodeSet& G) : Edge() { }
   984       EdgeIt (Invalid i) : Edge(i) { }
   985       EdgeIt() : Edge() { }
   986       ///\bug This is a workaround until somebody tells me how to
   987       ///make class \c SymNodeSet::SymEdgeMap friend of Edge
   988       //      int idref() {return -1;}
   989     };
   990     
   991     class OutEdgeIt : public Edge {
   992       friend class NodeSet;
   993     public: 
   994       OutEdgeIt() : Edge() { }
   995       OutEdgeIt (Invalid i) : Edge(i) { }
   996       OutEdgeIt(const NodeSet& G,const Node v)	: Edge() {}
   997     };
   998     
   999     class InEdgeIt : public Edge {
  1000       friend class NodeSet;
  1001     public: 
  1002       InEdgeIt() : Edge() { }
  1003       InEdgeIt (Invalid i) : Edge(i) { }
  1004       InEdgeIt(const NodeSet& G,Node v) :Edge() {}
  1005     };
  1006 
  1007     template <typename T> class NodeMap : public DynMapBase<Node>
  1008     {
  1009       std::vector<T> container;
  1010 
  1011     public:
  1012       typedef T ValueType;
  1013       typedef Node KeyType;
  1014 
  1015       NodeMap(const NodeSet &_G) :
  1016 	DynMapBase<Node>(_G), container(_G.maxNodeId())
  1017       {
  1018 	G->dyn_node_maps.push_back(this);
  1019       }
  1020       NodeMap(const NodeSet &_G,const T &t) :
  1021 	DynMapBase<Node>(_G), container(_G.maxNodeId(),t)
  1022       {
  1023 	G->dyn_node_maps.push_back(this);
  1024       }
  1025       
  1026       NodeMap(const NodeMap<T> &m) :
  1027  	DynMapBase<Node>(*m.G), container(m.container)
  1028       {
  1029  	G->dyn_node_maps.push_back(this);
  1030       }
  1031 
  1032       template<typename TT> friend class NodeMap;
  1033  
  1034       ///\todo It can copy between different types.
  1035       ///
  1036       template<typename TT> NodeMap(const NodeMap<TT> &m) :
  1037 	DynMapBase<Node>(*m.G), container(m.container.size())
  1038       {
  1039 	G->dyn_node_maps.push_back(this);
  1040 	typename std::vector<TT>::const_iterator i;
  1041 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
  1042 	    i!=m.container.end();
  1043 	    i++)
  1044 	  container.push_back(*i);
  1045       }
  1046       ~NodeMap()
  1047       {
  1048 	if(G) {
  1049 	  std::vector<DynMapBase<Node>* >::iterator i;
  1050 	  for(i=G->dyn_node_maps.begin();
  1051 	      i!=G->dyn_node_maps.end() && *i!=this; ++i) ;
  1052 	  //if(*i==this) G->dyn_node_maps.erase(i); //FIXME: Way too slow...
  1053 	  //A better way to do that: (Is this really important?)
  1054 	  if(*i==this) {
  1055 	    *i=G->dyn_node_maps.back();
  1056 	    G->dyn_node_maps.pop_back();
  1057 	  }
  1058 	}
  1059       }
  1060 
  1061       void add(const Node k) 
  1062       {
  1063 	if(k.n>=int(container.size())) container.resize(k.n+1);
  1064       }
  1065 
  1066       void erase(const Node) { }
  1067       
  1068       void set(Node n, T a) { container[n.n]=a; }
  1069       //'T& operator[](Node n)' would be wrong here
  1070       typename std::vector<T>::reference
  1071       operator[](Node n) { return container[n.n]; }
  1072       //'const T& operator[](Node n)' would be wrong here
  1073       typename std::vector<T>::const_reference 
  1074       operator[](Node n) const { return container[n.n]; }
  1075 
  1076       ///\warning There is no safety check at all!
  1077       ///Using operator = between maps attached to different graph may
  1078       ///cause serious problem.
  1079       ///\todo Is this really so?
  1080       ///\todo It can copy between different types.
  1081       const NodeMap<T>& operator=(const NodeMap<T> &m)
  1082       {
  1083 	container = m.container;
  1084 	return *this;
  1085       }
  1086       template<typename TT>
  1087       const NodeMap<T>& operator=(const NodeMap<TT> &m)
  1088       {
  1089 	std::copy(m.container.begin(), m.container.end(), container.begin());
  1090 	return *this;
  1091       }
  1092       
  1093       void update() {}    //Useless for Dynamic Maps
  1094       void update(T a) {}  //Useless for Dynamic Maps
  1095     };
  1096     
  1097     template <typename T> class EdgeMap
  1098     {
  1099     public:
  1100       typedef T ValueType;
  1101       typedef Edge KeyType;
  1102 
  1103       EdgeMap(const NodeSet &) { }
  1104       EdgeMap(const NodeSet &,const T &) { }
  1105       EdgeMap(const EdgeMap<T> &) { }
  1106       //      template<typename TT> friend class EdgeMap;
  1107 
  1108       ///\todo It can copy between different types.
  1109       ///
  1110       template<typename TT> EdgeMap(const EdgeMap<TT> &) { }
  1111       ~EdgeMap() { }
  1112 
  1113       void add(const Edge  ) { }
  1114       void erase(const Edge) { }
  1115       
  1116       void set(Edge, T) { }
  1117       //T get(Edge n) const { return container[n.n]; }
  1118       ValueType &operator[](Edge) { return *((T*)(NULL)); }
  1119       const ValueType &operator[](Edge) const { return *((T*)(NULL)); }
  1120 
  1121       const EdgeMap<T>& operator=(const EdgeMap<T> &) { return *this; }
  1122     
  1123       template<typename TT>
  1124       const EdgeMap<T>& operator=(const EdgeMap<TT> &m) { return *this; }
  1125       
  1126       void update() {}
  1127       void update(T a) {}
  1128     };
  1129   };
  1130 
  1131 
  1132 
  1133   ///Graph structure using a node set of another graph.
  1134 
  1135   ///This structure can be used to establish another graph over a node set
  1136   /// of an existing one. The node iterator will go through the nodes of the
  1137   /// original graph, and the NodeMap's of both graphs will convert to
  1138   /// each other.
  1139   ///
  1140   ///\warning Adding or deleting nodes from the graph is not safe if an
  1141   ///\ref EdgeSet is currently attached to it!
  1142   ///
  1143   ///\todo Make it possible to add/delete edges from the base graph
  1144   ///(and from \ref EdgeSet, as well)
  1145   ///
  1146   ///\param GG The type of the graph which shares its node set with this class.
  1147   ///Its interface must conform with \ref GraphSkeleton.
  1148   ///
  1149   ///It conforms to the graph interface documented under
  1150   ///the description of \ref GraphSkeleton.
  1151   ///\sa \ref GraphSkeleton.
  1152   ///\sa \ref NodeSet.
  1153   template<typename GG>
  1154   class EdgeSet {
  1155 
  1156     typedef GG NodeGraphType;
  1157 
  1158     NodeGraphType &G;
  1159 
  1160   public:
  1161     class Node;
  1162     int id(Node v) const; 
  1163 
  1164     class Node : public NodeGraphType::Node {
  1165       friend class EdgeSet;
  1166       //      template <typename T> friend class NodeMap;
  1167       
  1168       friend class Edge;
  1169       friend class OutEdgeIt;
  1170       friend class InEdgeIt;
  1171       friend class SymEdge;
  1172 
  1173     public:
  1174       friend int EdgeSet::id(Node v) const; 
  1175       //      Node(int nn) {n=nn;}
  1176     public:
  1177       Node() : NodeGraphType::Node() {}
  1178       Node (Invalid i) : NodeGraphType::Node(i) {}
  1179       Node(const typename NodeGraphType::Node &n) : NodeGraphType::Node(n) {}
  1180     };
  1181     
  1182     class NodeIt : public NodeGraphType::NodeIt {
  1183       friend class EdgeSet;
  1184     public:
  1185       NodeIt() : NodeGraphType::NodeIt() { }
  1186       NodeIt (Invalid i) : NodeGraphType::NodeIt(i) {}
  1187       NodeIt(const EdgeSet& _G) : NodeGraphType::NodeIt(_G.G) { }
  1188       NodeIt(const typename NodeGraphType::NodeIt &n)
  1189 	: NodeGraphType::NodeIt(n) {}
  1190       ///\todo Undocumented conversion Node -\> NodeIt.
  1191       NodeIt(const EdgeSet& _G, const Node &n)
  1192 	: NodeGraphType::NodeIt(_G.G,n) { }
  1193 
  1194       operator Node() { return Node(*this);}
  1195     };
  1196 
  1197   private:
  1198     //Edges are double linked.
  1199     //The free edges are only single linked using the "next_in" field.
  1200     struct NodeT 
  1201     {
  1202       int first_in,first_out;
  1203       NodeT() : first_in(-1), first_out(-1) { }
  1204     };
  1205 
  1206     struct EdgeT 
  1207     {
  1208       Node head, tail;
  1209       int prev_in, prev_out;
  1210       int next_in, next_out;
  1211     };
  1212 
  1213     
  1214     typename NodeGraphType::template NodeMap<NodeT> nodes;
  1215     
  1216     std::vector<EdgeT> edges;
  1217     //The first free edge
  1218     int first_free_edge;
  1219     
  1220   protected:
  1221     
  1222     template <typename Key> class DynMapBase
  1223     {
  1224     protected:
  1225       const EdgeSet* G; 
  1226     public:
  1227       virtual void add(const Key k) = 0;
  1228       virtual void erase(const Key k) = 0;
  1229       DynMapBase(const EdgeSet &_G) : G(&_G) {}
  1230       virtual ~DynMapBase() {}
  1231       friend class EdgeSet;
  1232     };
  1233     
  1234   public:
  1235     //template <typename T> class NodeMap;
  1236     template <typename T> class EdgeMap;
  1237     
  1238     class Node;
  1239     class Edge;
  1240 
  1241     //  protected:
  1242     // HELPME:
  1243   protected:
  1244     // mutable std::vector<DynMapBase<Node> * > dyn_node_maps;
  1245     ///\bug It must be public because of SymEdgeMap.
  1246     ///
  1247     mutable std::vector<DynMapBase<Edge> * > dyn_edge_maps;
  1248     
  1249   public:
  1250 
  1251     class NodeIt;
  1252     class EdgeIt;
  1253     class OutEdgeIt;
  1254     class InEdgeIt;
  1255     
  1256     template <typename T> class NodeMap;
  1257     template <typename T> class EdgeMap;
  1258     
  1259   public:
  1260 
  1261     ///Constructor
  1262     
  1263     ///Construates a new graph based on the nodeset of an existing one.
  1264     ///\param _G the base graph.
  1265     ///\todo It looks like a copy constructor, but it isn't.
  1266     EdgeSet(NodeGraphType &_G) : G(_G),
  1267 				 nodes(_G), edges(),
  1268 				 first_free_edge(-1) { }
  1269     ///Copy constructor
  1270 
  1271     ///Makes a copy of an EdgeSet.
  1272     ///It will be based on the same graph.
  1273     EdgeSet(const EdgeSet &_g) : G(_g.G), nodes(_g.G), edges(_g.edges),
  1274 				 first_free_edge(_g.first_free_edge) { }
  1275     
  1276     ~EdgeSet()
  1277     {
  1278       // for(std::vector<DynMapBase<Node> * >::iterator i=dyn_node_maps.begin();
  1279       //  i!=dyn_node_maps.end(); ++i) (**i).G=NULL;
  1280       for(typename std::vector<DynMapBase<Edge> * >::iterator
  1281 	    i=dyn_edge_maps.begin();
  1282 	  i!=dyn_edge_maps.end(); ++i) (**i).G=NULL;
  1283     }
  1284 
  1285     int nodeNum() const { return G.nodeNum(); }  //FIXME: What is this?
  1286     int edgeNum() const { return edges.size(); }  //FIXME: What is this?
  1287 
  1288     ///\bug This function does something different than
  1289     ///its name would suggests...
  1290     int maxNodeId() const { return G.maxNodeId(); }  //FIXME: What is this?
  1291     ///\bug This function does something different than
  1292     ///its name would suggests...
  1293     int maxEdgeId() const { return edges.size(); }  //FIXME: What is this?
  1294 
  1295     Node tail(Edge e) const { return edges[e.n].tail; }
  1296     Node head(Edge e) const { return edges[e.n].head; }
  1297 
  1298     Node aNode(OutEdgeIt e) const { return edges[e.n].tail; }
  1299     Node aNode(InEdgeIt e) const { return edges[e.n].head; }
  1300 
  1301     Node bNode(OutEdgeIt e) const { return edges[e.n].head; }
  1302     Node bNode(InEdgeIt e) const { return edges[e.n].tail; }
  1303 
  1304     NodeIt& first(NodeIt& v) const { 
  1305       v=NodeIt(*this); return v; }
  1306     EdgeIt& first(EdgeIt& e) const { 
  1307       e=EdgeIt(*this); return e; }
  1308     OutEdgeIt& first(OutEdgeIt& e, const Node v) const { 
  1309       e=OutEdgeIt(*this,v); return e; }
  1310     InEdgeIt& first(InEdgeIt& e, const Node v) const { 
  1311       e=InEdgeIt(*this,v); return e; }
  1312 
  1313 //     template< typename It >
  1314 //     It first() const { It e; first(e); return e; }
  1315 
  1316 //     template< typename It >
  1317 //     It first(Node v) const { It e; first(e,v); return e; }
  1318 
  1319     bool valid(Edge e) const { return e.n!=-1; }
  1320     bool valid(Node n) const { return G.valid(n); }
  1321     
  1322     void setInvalid(Edge &e) { e.n=-1; }
  1323     void setInvalid(Node &n) { G.setInvalid(n); }
  1324     
  1325     template <typename It> It getNext(It it) const
  1326     { It tmp(it); return next(tmp); }
  1327 
  1328     NodeIt& next(NodeIt& it) const { G.next(it); return it; }
  1329     OutEdgeIt& next(OutEdgeIt& it) const
  1330     { it.n=edges[it.n].next_out; return it; }
  1331     InEdgeIt& next(InEdgeIt& it) const
  1332     { it.n=edges[it.n].next_in; return it; }
  1333     EdgeIt& next(EdgeIt& it) const {
  1334       if(edges[it.n].next_in!=-1) { 
  1335 	it.n=edges[it.n].next_in;
  1336       }
  1337       else {
  1338 	NodeIt n(*this,edges[it.n].head);
  1339 	for(n=next(n);
  1340 	    valid(n) && nodes[n].first_in == -1;
  1341 	    next(n)) ;
  1342 	it.n = (valid(n))?-1:nodes[n].first_in;
  1343       }
  1344       return it;
  1345     }
  1346 
  1347     int id(Edge e) const { return e.n; }
  1348 
  1349     /// Adds a new node to the graph.
  1350     Node addNode() { return G.addNode(); }
  1351     
  1352     Edge addEdge(Node u, Node v) {
  1353       int n;
  1354       
  1355       if(first_free_edge==-1)
  1356 	{
  1357 	  n = edges.size();
  1358 	  edges.push_back(EdgeT());
  1359 	}
  1360       else {
  1361 	n = first_free_edge;
  1362 	first_free_edge = edges[n].next_in;
  1363       }
  1364       
  1365       edges[n].tail = u; edges[n].head = v;
  1366 
  1367       edges[n].next_out = nodes[u].first_out;
  1368       if(nodes[u].first_out != -1) edges[nodes[u].first_out].prev_out = n;
  1369       edges[n].next_in = nodes[v].first_in;
  1370       if(nodes[v].first_in != -1) edges[nodes[v].first_in].prev_in = n;
  1371       edges[n].prev_in = edges[n].prev_out = -1;
  1372 	
  1373       nodes[u].first_out = nodes[v].first_in = n;
  1374 
  1375       Edge e; e.n=n;
  1376 
  1377       //Update dynamic maps
  1378       for(typename std::vector<DynMapBase<Edge> * >::iterator
  1379 	    i=dyn_edge_maps.begin();
  1380 	  i!=dyn_edge_maps.end(); ++i) (**i).add(e);
  1381 
  1382       return e;
  1383     }
  1384 
  1385   private:
  1386     void eraseEdge(int n) {
  1387       
  1388       if(edges[n].next_in!=-1)
  1389 	edges[edges[n].next_in].prev_in = edges[n].prev_in;
  1390       if(edges[n].prev_in!=-1)
  1391 	edges[edges[n].prev_in].next_in = edges[n].next_in;
  1392       else nodes[edges[n].head].first_in = edges[n].next_in;
  1393       
  1394       if(edges[n].next_out!=-1)
  1395 	edges[edges[n].next_out].prev_out = edges[n].prev_out;
  1396       if(edges[n].prev_out!=-1)
  1397 	edges[edges[n].prev_out].next_out = edges[n].next_out;
  1398       else nodes[edges[n].tail].first_out = edges[n].next_out;
  1399       
  1400       edges[n].next_in = first_free_edge;
  1401       first_free_edge = -1;      
  1402 
  1403       //Update dynamic maps
  1404       Edge e; e.n=n;
  1405       for(typename std::vector<DynMapBase<Edge> * >::iterator
  1406 	    i=dyn_edge_maps.begin();
  1407 	  i!=dyn_edge_maps.end(); ++i) (**i).erase(e);
  1408     }
  1409       
  1410   public:
  1411 
  1412 //     void erase(Node nn) {
  1413 //       int n=nn.n;
  1414 //       int m;
  1415 //       while((m=nodes[n].first_in)!=-1) eraseEdge(m);
  1416 //       while((m=nodes[n].first_out)!=-1) eraseEdge(m);
  1417 //     }
  1418     
  1419     void erase(Edge e) { eraseEdge(e.n); }
  1420 
  1421     ///Clear all edges. (Doesn't clear the nodes!)
  1422     void clear() {
  1423       edges.clear();
  1424       first_free_edge=-1;
  1425     }
  1426 
  1427 
  1428 //     //\bug Dynamic maps must be updated!
  1429 //     //
  1430 //     void clear() {
  1431 //       nodes.clear();edges.clear();
  1432 //       first_node=first_free_node=first_free_edge=-1;
  1433 //     }
  1434 
  1435   public:
  1436     template <typename T> class EdgeMap;
  1437     
  1438     ///
  1439     class Edge {
  1440     public:
  1441       friend class EdgeSet;
  1442       template <typename T> friend class EdgeMap;
  1443 
  1444       friend class Node;
  1445       friend class NodeIt;
  1446     public:
  1447       ///\bug It shoud be at least protected
  1448       ///
  1449       int n;
  1450     protected:
  1451       friend int EdgeSet::id(Edge e) const;
  1452 
  1453       Edge(int nn) {n=nn;}
  1454     public:
  1455       Edge() { }
  1456       Edge (Invalid) { n=-1; }
  1457       bool operator==(const Edge i) const {return n==i.n;}
  1458       bool operator!=(const Edge i) const {return n!=i.n;}
  1459       bool operator<(const Edge i) const {return n<i.n;}
  1460       ///\bug This is a workaround until somebody tells me how to
  1461       ///make class \c SymEdgeSet::SymEdgeMap friend of Edge
  1462       int &idref() {return n;}
  1463       const int &idref() const {return n;}
  1464     };
  1465     
  1466     class EdgeIt : public Edge {
  1467       friend class EdgeSet;
  1468       template <typename T> friend class EdgeMap;
  1469     
  1470       
  1471     public:
  1472       EdgeIt(const EdgeSet& G) : Edge() {
  1473 	//      	typename NodeGraphType::Node m;
  1474         NodeIt m;
  1475 	for(G.first(m);
  1476 	    G.valid(m) && G.nodes[m].first_in == -1;  G.next(m));
  1477 	//AJJAJ! This is a non sense!!!!!!!
  1478 	this->n = G.valid(m)?-1:G.nodes[m].first_in;
  1479       }
  1480       EdgeIt (Invalid i) : Edge(i) { }
  1481       EdgeIt() : Edge() { }
  1482       ///\bug This is a workaround until somebody tells me how to
  1483       ///make class \c SymEdgeSet::SymEdgeMap friend of Edge
  1484       int &idref() {return this->n;}
  1485     };
  1486     
  1487     class OutEdgeIt : public Edge {
  1488       friend class EdgeSet;
  1489     public: 
  1490       OutEdgeIt() : Edge() { }
  1491       OutEdgeIt (Invalid i) : Edge(i) { }
  1492 
  1493       OutEdgeIt(const EdgeSet& G,const Node v) : Edge(G.nodes[v].first_out) { }
  1494     };
  1495     
  1496     class InEdgeIt : public Edge {
  1497       friend class EdgeSet;
  1498     public: 
  1499       InEdgeIt() : Edge() { }
  1500       InEdgeIt (Invalid i) : Edge(i) { }
  1501       InEdgeIt(const EdgeSet& G,Node v) :Edge(G.nodes[v].first_in) { }
  1502     };
  1503 
  1504     template <typename T> class NodeMap : 
  1505       public NodeGraphType::template NodeMap<T>
  1506     {
  1507       //This is a must, the constructors need it.
  1508       typedef typename NodeGraphType::template NodeMap<T> ParentNodeMap;
  1509     public:
  1510       NodeMap(const EdgeSet &_G) : ParentNodeMap(_G.G) { }
  1511       NodeMap(const EdgeSet &_G,const T &t) : ParentNodeMap(_G.G,t) { }
  1512       //It is unnecessary
  1513       NodeMap(const typename NodeGraphType::template NodeMap<T> &m) :
  1514 	ParentNodeMap(m) { }
  1515 
  1516       ///\todo It can copy between different types.
  1517       ///
  1518       template<typename TT>
  1519       NodeMap(const typename NodeGraphType::template NodeMap<TT> &m)
  1520 	: ParentNodeMap(m) { }
  1521     };
  1522     
  1523     ///
  1524     template <typename T> class EdgeMap : public DynMapBase<Edge>
  1525     {
  1526     protected:
  1527     public:
  1528       ///\bug It should be at least protected
  1529       ///
  1530       std::vector<T> container;
  1531 
  1532     public:
  1533       typedef T ValueType;
  1534       typedef Edge KeyType;
  1535 
  1536       EdgeMap(const EdgeSet &_G) :
  1537 	DynMapBase<Edge>(_G), container(_G.maxEdgeId())
  1538       {
  1539 	//FIXME: What if there are empty Id's?
  1540 	//FIXME: Can I use 'this' in a constructor?
  1541 	G->dyn_edge_maps.push_back(this);
  1542       }
  1543       EdgeMap(const EdgeSet &_G,const T &t) :
  1544 	DynMapBase<Edge>(_G), container(_G.maxEdgeId(),t)
  1545       {
  1546 	G->dyn_edge_maps.push_back(this);
  1547       } 
  1548       EdgeMap(const EdgeMap<T> &m) :
  1549  	DynMapBase<Edge>(*m.G), container(m.container)
  1550       {
  1551  	G->dyn_edge_maps.push_back(this);
  1552       }
  1553 
  1554       template<typename TT> friend class EdgeMap;
  1555 
  1556       ///\todo It can copy between different types.
  1557       ///
  1558       template<typename TT> EdgeMap(const EdgeMap<TT> &m) :
  1559 	DynMapBase<Edge>(*m.G), container(m.container.size())
  1560       {
  1561 	G->dyn_edge_maps.push_back(this);
  1562 	typename std::vector<TT>::const_iterator i;
  1563 	for(typename std::vector<TT>::const_iterator i=m.container.begin();
  1564 	    i!=m.container.end();
  1565 	    i++)
  1566 	  container.push_back(*i);
  1567       }
  1568       ~EdgeMap()
  1569       {
  1570 	if(G) {
  1571 	  typename std::vector<DynMapBase<Edge>* >::iterator i;
  1572 	  for(i=G->dyn_edge_maps.begin();
  1573 	      i!=G->dyn_edge_maps.end() && *i!=this; ++i) ;
  1574 	  //if(*i==this) G->dyn_edge_maps.erase(i); //Way too slow...
  1575 	  //A better way to do that: (Is this really important?)
  1576 	  if(*i==this) {
  1577 	    *i=G->dyn_edge_maps.back();
  1578 	    G->dyn_edge_maps.pop_back();
  1579 	  }
  1580 	}
  1581       }
  1582       
  1583       void add(const Edge k) 
  1584       {
  1585 	if(k.n>=int(container.size())) container.resize(k.n+1);
  1586       }
  1587       void erase(const Edge) { }
  1588       
  1589       ///\bug This doesn't work. Why?
  1590       ///      void set(Edge n, T a) { container[n.n]=a; }
  1591       void set(Edge n, T a) { container[G->id(n)]=a; }
  1592       //T get(Edge n) const { return container[n.n]; }
  1593       typename std::vector<T>::reference
  1594       ///\bug This doesn't work. Why?
  1595       ///      operator[](Edge n) { return container[n.n]; }
  1596       operator[](Edge n) { return container[G->id(n)]; }
  1597       typename std::vector<T>::const_reference
  1598       ///\bug This doesn't work. Why?
  1599       ///      operator[](Edge n) const { return container[n.n]; }
  1600       operator[](Edge n) const { return container[G->id(n)]; }
  1601 
  1602       ///\warning There is no safety check at all!
  1603       ///Using operator = between maps attached to different graph may
  1604       ///cause serious problem.
  1605       ///\todo Is this really so?
  1606       ///\todo It can copy between different types.
  1607       const EdgeMap<T>& operator=(const EdgeMap<T> &m)
  1608       {
  1609 	container = m.container;
  1610 	return *this;
  1611       }
  1612       
  1613       template<typename TT> friend class EdgeMap;
  1614 
  1615       template<typename TT>
  1616       const EdgeMap<T>& operator=(const EdgeMap<TT> &m)
  1617       {
  1618 	std::copy(m.container.begin(), m.container.end(), container.begin());
  1619 	return *this;
  1620       }
  1621       
  1622       void update() {}    //Useless for DynMaps
  1623       void update(T a) {}  //Useless for DynMaps
  1624     };
  1625 
  1626   };
  1627 
  1628   template<typename GG>
  1629   inline int EdgeSet<GG>::id(Node v) const { return G.id(v); }
  1630 
  1631 /// @}  
  1632 
  1633 } //namespace hugo
  1634 
  1635 #endif //HUGO_LIST_GRAPH_H