COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/list_graph.h @ 937:d4e911acef3d

Last change on this file since 937:d4e911acef3d was 937:d4e911acef3d, checked in by Balazs Dezso, 16 years ago

Revert backport changes -r1230.

File size: 40.5 KB
Line 
1/* -*- C++ -*-
2 * src/lemon/list_graph.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, EGRES).
6 *
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
10 *
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
13 * purpose.
14 *
15 */
16
17#ifndef LEMON_LIST_GRAPH_H
18#define LEMON_LIST_GRAPH_H
19
20///\ingroup graphs
21///\file
22///\brief ListGraph, SymListGraph, NodeSet and EdgeSet classes.
23
24#include <vector>
25#include <climits>
26
27#include <lemon/invalid.h>
28
29#include <lemon/map_registry.h>
30#include <lemon/array_map.h>
31
32#include <lemon/map_defines.h>
33
34
35namespace lemon {
36
37/// \addtogroup graphs
38/// @{
39
40  ///A list graph class.
41
42  ///This is a simple and fast erasable graph implementation.
43  ///
44  ///It conforms to the
45  ///\ref skeleton::ErasableGraph "ErasableGraph" concept.
46  ///\sa skeleton::ErasableGraph.
47  class ListGraph {
48
49    //Nodes are double linked.
50    //The free nodes are only single linked using the "next" field.
51    struct NodeT
52    {
53      int first_in,first_out;
54      int prev, next;
55    };
56    //Edges are double linked.
57    //The free edges are only single linked using the "next_in" field.
58    struct EdgeT
59    {
60      int head, tail;
61      int prev_in, prev_out;
62      int next_in, next_out;
63    };
64
65    std::vector<NodeT> nodes;
66    //The first node
67    int first_node;
68    //The first free node
69    int first_free_node;
70    std::vector<EdgeT> edges;
71    //The first free edge
72    int first_free_edge;
73   
74  public:
75   
76    typedef ListGraph Graph;
77   
78    class Node;
79    class Edge;
80
81   
82  public:
83
84    class NodeIt;
85    class EdgeIt;
86    class OutEdgeIt;
87    class InEdgeIt;
88
89    // Create map registries.
90    CREATE_MAP_REGISTRIES;
91    // Create node and edge maps.
92    CREATE_MAPS(ArrayMap);
93
94  public:
95
96    ListGraph()
97      : nodes(), first_node(-1),
98        first_free_node(-1), edges(), first_free_edge(-1) {}
99
100    ListGraph(const ListGraph &_g)
101      : nodes(_g.nodes), first_node(_g.first_node),
102        first_free_node(_g.first_free_node), edges(_g.edges),
103        first_free_edge(_g.first_free_edge) {}
104   
105    /// \bug In the vector can be hole if a node is erased from the graph.
106    ///Number of nodes.
107    int nodeNum() const { return nodes.size(); }
108    ///Number of edges.
109    int edgeNum() const { return edges.size(); }
110
111    ///Set the expected maximum number of edges.
112
113    ///With this function, it is possible to set the expected number of edges.
114    ///The use of this fasten the building of the graph and makes
115    ///it possible to avoid the superfluous memory allocation.
116    void reserveEdge(int n) { edges.reserve(n); };
117   
118    /// Maximum node ID.
119   
120    /// Maximum node ID.
121    ///\sa id(Node)
122    int maxNodeId() const { return nodes.size()-1; }
123    /// Maximum edge ID.
124   
125    /// Maximum edge ID.
126    ///\sa id(Edge)
127    int maxEdgeId() const { return edges.size()-1; }
128
129    Node tail(Edge e) const { return edges[e.n].tail; }
130    Node head(Edge e) const { return edges[e.n].head; }
131
132    NodeIt& first(NodeIt& v) const {
133      v=NodeIt(*this); return v; }
134    EdgeIt& first(EdgeIt& e) const {
135      e=EdgeIt(*this); return e; }
136    OutEdgeIt& first(OutEdgeIt& e, const Node v) const {
137      e=OutEdgeIt(*this,v); return e; }
138    InEdgeIt& first(InEdgeIt& e, const Node v) const {
139      e=InEdgeIt(*this,v); return e; }
140
141    /// Node ID.
142   
143    /// The ID of a valid Node is a nonnegative integer not greater than
144    /// \ref maxNodeId(). The range of the ID's is not surely continuous
145    /// and the greatest node ID can be actually less then \ref maxNodeId().
146    ///
147    /// The ID of the \ref INVALID node is -1.
148    ///\return The ID of the node \c v.
149    static int id(Node v) { return v.n; }
150    /// Edge ID.
151   
152    /// The ID of a valid Edge is a nonnegative integer not greater than
153    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
154    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
155    ///
156    /// The ID of the \ref INVALID edge is -1.
157    ///\return The ID of the edge \c e.
158    static int id(Edge e) { return e.n; }
159
160    /// Adds a new node to the graph.
161
162    /// \warning It adds the new node to the front of the list.
163    /// (i.e. the lastly added node becomes the first.)
164    Node addNode() {
165      int n;
166     
167      if(first_free_node==-1)
168        {
169          n = nodes.size();
170          nodes.push_back(NodeT());
171        }
172      else {
173        n = first_free_node;
174        first_free_node = nodes[n].next;
175      }
176     
177      nodes[n].next = first_node;
178      if(first_node != -1) nodes[first_node].prev = n;
179      first_node = n;
180      nodes[n].prev = -1;
181     
182      nodes[n].first_in = nodes[n].first_out = -1;
183     
184      Node nn; nn.n=n;
185
186      //Update dynamic maps
187      node_maps.add(nn);
188
189      return nn;
190    }
191   
192    Edge addEdge(Node u, Node v) {
193      int n;
194     
195      if(first_free_edge==-1)
196        {
197          n = edges.size();
198          edges.push_back(EdgeT());
199        }
200      else {
201        n = first_free_edge;
202        first_free_edge = edges[n].next_in;
203      }
204     
205      edges[n].tail = u.n; edges[n].head = v.n;
206
207      edges[n].next_out = nodes[u.n].first_out;
208      if(nodes[u.n].first_out != -1) edges[nodes[u.n].first_out].prev_out = n;
209      edges[n].next_in = nodes[v.n].first_in;
210      if(nodes[v.n].first_in != -1) edges[nodes[v.n].first_in].prev_in = n;
211      edges[n].prev_in = edges[n].prev_out = -1;
212       
213      nodes[u.n].first_out = nodes[v.n].first_in = n;
214
215      Edge e; e.n=n;
216
217      //Update dynamic maps
218      edge_maps.add(e);
219
220      return e;
221    }
222   
223    /// Finds an edge between two nodes.
224
225    /// Finds an edge from node \c u to node \c v.
226    ///
227    /// If \c prev is \ref INVALID (this is the default value), then
228    /// It finds the first edge from \c u to \c v. Otherwise it looks for
229    /// the next edge from \c u to \c v after \c prev.
230    /// \return The found edge or INVALID if there is no such an edge.
231    Edge findEdge(Node u,Node v, Edge prev = INVALID)
232    {
233      int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out;
234      while(e!=-1 && edges[e].tail!=v.n) e = edges[e].next_out;
235      prev.n=e;
236      return prev;
237    }
238   
239  private:
240    void eraseEdge(int n) {
241     
242      if(edges[n].next_in!=-1)
243        edges[edges[n].next_in].prev_in = edges[n].prev_in;
244      if(edges[n].prev_in!=-1)
245        edges[edges[n].prev_in].next_in = edges[n].next_in;
246      else nodes[edges[n].head].first_in = edges[n].next_in;
247     
248      if(edges[n].next_out!=-1)
249        edges[edges[n].next_out].prev_out = edges[n].prev_out;
250      if(edges[n].prev_out!=-1)
251        edges[edges[n].prev_out].next_out = edges[n].next_out;
252      else nodes[edges[n].tail].first_out = edges[n].next_out;
253     
254      edges[n].next_in = first_free_edge;
255      first_free_edge = n;     
256
257      //Update dynamic maps
258      Edge e; e.n=n;
259      edge_maps.erase(e);
260
261    }
262     
263  public:
264
265    void erase(Node nn) {
266      int n=nn.n;
267     
268      int m;
269      while((m=nodes[n].first_in)!=-1) eraseEdge(m);
270      while((m=nodes[n].first_out)!=-1) eraseEdge(m);
271
272      if(nodes[n].next != -1) nodes[nodes[n].next].prev = nodes[n].prev;
273      if(nodes[n].prev != -1) nodes[nodes[n].prev].next = nodes[n].next;
274      else first_node = nodes[n].next;
275     
276      nodes[n].next = first_free_node;
277      first_free_node = n;
278
279      //Update dynamic maps
280      node_maps.erase(nn);
281
282    }
283   
284    void erase(Edge e) { eraseEdge(e.n); }
285
286    void clear() {
287      edge_maps.clear();
288      edges.clear();
289      node_maps.clear();
290      nodes.clear();
291      first_node=first_free_node=first_free_edge=-1;
292    }
293
294    class Node {
295      friend class ListGraph;
296      template <typename T> friend class NodeMap;
297       
298      friend class Edge;
299      friend class OutEdgeIt;
300      friend class InEdgeIt;
301      friend class SymEdge;
302
303    protected:
304      int n;
305      friend int ListGraph::id(Node v);
306      Node(int nn) {n=nn;}
307    public:
308      Node() {}
309      Node (Invalid) { n=-1; }
310      bool operator==(const Node i) const {return n==i.n;}
311      bool operator!=(const Node i) const {return n!=i.n;}
312      bool operator<(const Node i) const {return n<i.n;}
313      //      ///Validity check
314      //      operator bool() { return n!=-1; }
315    };
316   
317    class NodeIt : public Node {
318      const ListGraph *G;
319      friend class ListGraph;
320    public:
321      NodeIt() : Node() { }
322      NodeIt(Invalid i) : Node(i) { }
323      NodeIt(const ListGraph& _G) : Node(_G.first_node), G(&_G) { }
324      NodeIt(const ListGraph& _G,Node n) : Node(n), G(&_G) { }
325      NodeIt &operator++() {
326        n=G->nodes[n].next;
327        return *this;
328      }
329      //      ///Validity check
330      //      operator bool() { return Node::operator bool(); }     
331    };
332
333    class Edge {
334      friend class ListGraph;
335      template <typename T> friend class EdgeMap;
336
337      friend class SymListGraph;
338     
339      friend class Node;
340      friend class NodeIt;
341    protected:
342      int n;
343      friend int ListGraph::id(Edge e);
344
345    public:
346      /// An Edge with id \c n.
347
348      /// \bug It should be
349      /// obtained by a member function of the Graph.
350      Edge(int nn) {n=nn;}
351
352      Edge() { }
353      Edge (Invalid) { n=-1; }
354      bool operator==(const Edge i) const {return n==i.n;}
355      bool operator!=(const Edge i) const {return n!=i.n;}
356      bool operator<(const Edge i) const {return n<i.n;}
357      //      ///Validity check
358      //      operator bool() { return n!=-1; }
359   };
360   
361    class EdgeIt : public Edge {
362      const ListGraph *G;
363      friend class ListGraph;
364    public:
365      EdgeIt(const ListGraph& _G) : Edge(), G(&_G) {
366        int m;
367        for(m=_G.first_node;
368            m!=-1 && _G.nodes[m].first_in == -1; m = _G.nodes[m].next);
369        n = (m==-1)?-1:_G.nodes[m].first_in;
370      }
371      EdgeIt (Invalid i) : Edge(i) { }
372      EdgeIt(const ListGraph& _G, Edge e) : Edge(e), G(&_G) { }
373      EdgeIt() : Edge() { }
374      EdgeIt &operator++() {
375        if(G->edges[n].next_in!=-1) n=G->edges[n].next_in;
376        else {
377          int nn;
378          for(nn=G->nodes[G->edges[n].head].next;
379              nn!=-1 && G->nodes[nn].first_in == -1;
380              nn = G->nodes[nn].next) ;
381          n = (nn==-1)?-1:G->nodes[nn].first_in;
382        }
383        return *this;
384      }
385      //      ///Validity check
386      //      operator bool() { return Edge::operator bool(); }     
387    };
388   
389    class OutEdgeIt : public Edge {
390      const ListGraph *G;
391      friend class ListGraph;
392    public:
393      OutEdgeIt() : Edge() { }
394      OutEdgeIt(const ListGraph& _G, Edge e) : Edge(e), G(&_G) { }
395      OutEdgeIt (Invalid i) : Edge(i) { }
396
397      OutEdgeIt(const ListGraph& _G,const Node v)
398        : Edge(_G.nodes[v.n].first_out), G(&_G) {}
399      OutEdgeIt &operator++() { n=G->edges[n].next_out; return *this; }
400      //      ///Validity check
401      //      operator bool() { return Edge::operator bool(); }     
402    };
403   
404    class InEdgeIt : public Edge {
405      const ListGraph *G;
406      friend class ListGraph;
407    public:
408      InEdgeIt() : Edge() { }
409      InEdgeIt(const ListGraph& _G, Edge e) : Edge(e), G(&_G) { }
410      InEdgeIt (Invalid i) : Edge(i) { }
411      InEdgeIt(const ListGraph& _G,Node v)
412        : Edge(_G.nodes[v.n].first_in), G(&_G) { }
413      InEdgeIt &operator++() { n=G->edges[n].next_in; return *this; }
414      //      ///Validity check
415      //      operator bool() { return Edge::operator bool(); }     
416    };
417  };
418
419  ///Graph for bidirectional edges.
420
421  ///The purpose of this graph structure is to handle graphs
422  ///having bidirectional edges. Here the function \c addEdge(u,v) adds a pair
423  ///of oppositely directed edges.
424  ///There is a new edge map type called
425  ///\ref lemon::SymListGraph::SymEdgeMap "SymEdgeMap"
426  ///that complements this
427  ///feature by
428  ///storing shared values for the edge pairs. The usual
429  ///\ref lemon::skeleton::StaticGraph::EdgeMap "EdgeMap"
430  ///can be used
431  ///as well.
432  ///
433  ///The oppositely directed edge can also be obtained easily
434  ///using \ref lemon::SymListGraph::opposite() "opposite()" member function.
435  ///
436  ///Here erase(Edge) deletes a pair of edges.
437  ///
438  ///\todo this date structure need some reconsiderations. Maybe it
439  ///should be implemented independently from ListGraph.
440  /* 
441  class SymListGraph : public ListGraph
442  {
443  public:
444
445    typedef SymListGraph Graph;
446
447    // Create symmetric map registry.
448    CREATE_SYM_EDGE_MAP_REGISTRY;
449    // Create symmetric edge map.
450    CREATE_SYM_EDGE_MAP(ArrayMap);
451
452    SymListGraph() : ListGraph() { }
453    SymListGraph(const ListGraph &_g) : ListGraph(_g) { }
454    ///Adds a pair of oppositely directed edges to the graph.
455    Edge addEdge(Node u, Node v)
456    {
457      Edge e = ListGraph::addEdge(u,v);
458      Edge f = ListGraph::addEdge(v,u);
459      sym_edge_maps.add(e);
460      sym_edge_maps.add(f);
461     
462      return e;
463    }
464
465    void erase(Node n) { ListGraph::erase(n);}
466    ///The oppositely directed edge.
467
468    ///Returns the oppositely directed
469    ///pair of the edge \c e.
470    static Edge opposite(Edge e)
471    {
472      Edge f;
473      f.n = e.n - 2*(e.n%2) + 1;
474      return f;
475    }
476   
477    ///Removes a pair of oppositely directed edges to the graph.
478    void erase(Edge e) {
479      Edge f = opposite(e);
480      sym_edge_maps.erase(e);
481      sym_edge_maps.erase(f);
482      ListGraph::erase(f);
483      ListGraph::erase(e);
484    }   
485    };*/
486
487  class SymListGraph : public ListGraph {
488    typedef ListGraph Parent;
489  public:
490
491    typedef SymListGraph Graph;
492
493    typedef ListGraph::Node Node;
494    typedef ListGraph::NodeIt NodeIt;
495
496    class SymEdge;
497    class SymEdgeIt;
498
499    class Edge;
500    class EdgeIt;
501    class OutEdgeIt;
502    class InEdgeIt;
503
504    template <typename Value>
505    class NodeMap : public Parent::NodeMap<Value> {     
506    public:
507      NodeMap(const SymListGraph& g)
508        : SymListGraph::Parent::NodeMap<Value>(g) {}
509      NodeMap(const SymListGraph& g, Value v)
510        : SymListGraph::Parent::NodeMap<Value>(g, v) {}
511      template<typename TT>
512      NodeMap(const NodeMap<TT>& copy)
513        : SymListGraph::Parent::NodeMap<Value>(copy) { }           
514    };
515
516    template <typename Value>
517    class SymEdgeMap : public Parent::EdgeMap<Value> {
518    public:
519      typedef SymEdge KeyType;
520
521      SymEdgeMap(const SymListGraph& g)
522        : SymListGraph::Parent::EdgeMap<Value>(g) {}
523      SymEdgeMap(const SymListGraph& g, Value v)
524        : SymListGraph::Parent::EdgeMap<Value>(g, v) {}
525      template<typename TT>
526      SymEdgeMap(const SymEdgeMap<TT>& copy)
527        : SymListGraph::Parent::EdgeMap<Value>(copy) { }
528     
529    };
530
531    // Create edge map registry.
532    CREATE_EDGE_MAP_REGISTRY;
533    // Create edge maps.
534    CREATE_EDGE_MAP(ArrayMap);
535
536    class Edge {
537      friend class SymListGraph;
538      friend class SymListGraph::EdgeIt;
539      friend class SymListGraph::OutEdgeIt;
540      friend class SymListGraph::InEdgeIt;
541     
542    protected:
543      int id;
544
545      Edge(int pid) { id = pid; }
546
547    public:
548      /// An Edge with id \c n.
549
550      Edge() { }
551      Edge (Invalid) { id = -1; }
552
553      operator SymEdge(){ return SymEdge(id >> 1);}
554     
555      bool operator==(const Edge i) const {return id == i.id;}
556      bool operator!=(const Edge i) const {return id != i.id;}
557      bool operator<(const Edge i) const {return id < i.id;}
558      //      ///Validity check
559      //      operator bool() { return n!=-1; }
560    };
561
562    class SymEdge : public ListGraph::Edge {
563      friend class SymListGraph;
564      friend class SymListGraph::Edge;
565      typedef ListGraph::Edge Parent;
566
567    protected:     
568      SymEdge(int pid) : Parent(pid) {}
569    public:
570
571      SymEdge() { }
572      SymEdge(const ListGraph::Edge& i) : Parent(i) {}
573      SymEdge (Invalid) : Parent(INVALID) {}
574
575    };
576
577    class OutEdgeIt {
578      Parent::OutEdgeIt out;
579      Parent::InEdgeIt in;     
580    public:
581      OutEdgeIt() {}
582      OutEdgeIt(const SymListGraph& g, Edge e) {
583        if ((e.id & 1) == 0) { 
584          out = Parent::OutEdgeIt(g, SymEdge(e));
585          in = Parent::InEdgeIt(g, g.tail(e));
586        } else {
587          out = Parent::OutEdgeIt(INVALID);
588          in = Parent::InEdgeIt(g, SymEdge(e));
589        }
590      }
591      OutEdgeIt (Invalid i) : out(INVALID), in(INVALID) { }
592
593      OutEdgeIt(const SymListGraph& g, const Node v)
594        : out(g, v), in(g, v) {}
595      OutEdgeIt &operator++() {
596        if (out != INVALID) {
597          ++out;
598        } else {
599          ++in;
600        }
601        return *this;
602      }
603
604      operator Edge() const {
605        if (out == INVALID && in == INVALID) return INVALID;
606        return out != INVALID ? forward(out) : backward(in);
607      }
608
609      bool operator==(const Edge i) const {return Edge(*this) == i;}
610      bool operator!=(const Edge i) const {return Edge(*this) != i;}
611      bool operator<(const Edge i) const {return Edge(*this) < i;}
612    };
613
614    class InEdgeIt {
615      Parent::OutEdgeIt out;
616      Parent::InEdgeIt in;     
617    public:
618      InEdgeIt() {}
619      InEdgeIt(const SymListGraph& g, Edge e) {
620        if ((e.id & 1) == 0) { 
621          out = Parent::OutEdgeIt(g, SymEdge(e));
622          in = Parent::InEdgeIt(g, g.tail(e));
623        } else {
624          out = Parent::OutEdgeIt(INVALID);
625          in = Parent::InEdgeIt(g, SymEdge(e));
626        }
627      }
628      InEdgeIt (Invalid i) : out(INVALID), in(INVALID) { }
629
630      InEdgeIt(const SymListGraph& g, const Node v)
631        : out(g, v), in(g, v) {}
632
633      InEdgeIt &operator++() {
634        if (out != INVALID) {
635          ++out;
636        } else {
637          ++in;
638        }
639        return *this;
640      }
641
642      operator Edge() const {
643        if (out == INVALID && in == INVALID) return INVALID;
644        return out != INVALID ? backward(out) : forward(in);
645      }
646
647      bool operator==(const Edge i) const {return Edge(*this) == i;}
648      bool operator!=(const Edge i) const {return Edge(*this) != i;}
649      bool operator<(const Edge i) const {return Edge(*this) < i;}
650    };
651
652    class SymEdgeIt : public Parent::EdgeIt {
653
654    public:
655      SymEdgeIt() {}
656
657      SymEdgeIt(const SymListGraph& g)
658        : SymListGraph::Parent::EdgeIt(g) {}
659
660      SymEdgeIt(const SymListGraph& g, SymEdge e)
661        : SymListGraph::Parent::EdgeIt(g, e) {}
662
663      SymEdgeIt(Invalid i)
664        : SymListGraph::Parent::EdgeIt(INVALID) {}
665
666      SymEdgeIt& operator++() {
667        SymListGraph::Parent::EdgeIt::operator++();
668        return *this;
669      }
670
671      operator SymEdge() const {
672        return SymEdge
673          (static_cast<const SymListGraph::Parent::EdgeIt&>(*this));
674      }
675      bool operator==(const SymEdge i) const {return SymEdge(*this) == i;}
676      bool operator!=(const SymEdge i) const {return SymEdge(*this) != i;}
677      bool operator<(const SymEdge i) const {return SymEdge(*this) < i;}
678    };
679
680    class EdgeIt {
681      SymEdgeIt it;
682      bool fw;
683    public:
684      EdgeIt(const SymListGraph& g) : it(g), fw(true) {}
685      EdgeIt (Invalid i) : it(i) { }
686      EdgeIt(const SymListGraph& g, Edge e)
687        : it(g, SymEdge(e)), fw(id(e) & 1 == 0) { }
688      EdgeIt() { }
689      EdgeIt& operator++() {
690        fw = !fw;
691        if (fw) ++it;
692        return *this;
693      }
694      operator Edge() const {
695        if (it == INVALID) return INVALID;
696        return fw ? forward(it) : backward(it);
697      }
698      bool operator==(const Edge i) const {return Edge(*this) == i;}
699      bool operator!=(const Edge i) const {return Edge(*this) != i;}
700      bool operator<(const Edge i) const {return Edge(*this) < i;}
701
702    };
703
704    ///Number of nodes.
705    int nodeNum() const { return Parent::nodeNum(); }
706    ///Number of edges.
707    int edgeNum() const { return 2*Parent::edgeNum(); }
708    ///Number of symmetric edges.
709    int symEdgeNum() const { return Parent::edgeNum(); }
710
711    ///Set the expected maximum number of edges.
712
713    ///With this function, it is possible to set the expected number of edges.
714    ///The use of this fasten the building of the graph and makes
715    ///it possible to avoid the superfluous memory allocation.
716    void reserveSymEdge(int n) { Parent::reserveEdge(n); };
717   
718    /// Maximum node ID.
719   
720    /// Maximum node ID.
721    ///\sa id(Node)
722    int maxNodeId() const { return Parent::maxNodeId(); }
723    /// Maximum edge ID.
724   
725    /// Maximum edge ID.
726    ///\sa id(Edge)
727    int maxEdgeId() const { return 2*Parent::maxEdgeId(); }
728    /// Maximum symmetric edge ID.
729   
730    /// Maximum symmetric edge ID.
731    ///\sa id(SymEdge)
732    int maxSymEdgeId() const { return Parent::maxEdgeId(); }
733
734
735    Node tail(Edge e) const {
736      return (e.id & 1) == 0 ?
737        Parent::tail(SymEdge(e)) : Parent::head(SymEdge(e));
738    }
739
740    Node head(Edge e) const {
741      return (e.id & 1) == 0 ?
742        Parent::head(SymEdge(e)) : Parent::tail(SymEdge(e));
743    }
744
745    Node tail(SymEdge e) const {
746      return Parent::tail(e);
747    }
748
749    Node head(SymEdge e) const {
750      return Parent::head(e);
751    }
752
753    NodeIt& first(NodeIt& v) const {
754      v=NodeIt(*this); return v; }
755    EdgeIt& first(EdgeIt& e) const {
756      e=EdgeIt(*this); return e; }
757    SymEdgeIt& first(SymEdgeIt& e) const {
758      e=SymEdgeIt(*this); return e; }
759    OutEdgeIt& first(OutEdgeIt& e, const Node v) const {
760      e=OutEdgeIt(*this,v); return e; }
761    InEdgeIt& first(InEdgeIt& e, const Node v) const {
762      e=InEdgeIt(*this,v); return e; }
763
764    /// Node ID.
765   
766    /// The ID of a valid Node is a nonnegative integer not greater than
767    /// \ref maxNodeId(). The range of the ID's is not surely continuous
768    /// and the greatest node ID can be actually less then \ref maxNodeId().
769    ///
770    /// The ID of the \ref INVALID node is -1.
771    ///\return The ID of the node \c v.
772    static int id(Node v) { return Parent::id(v); }
773    /// Edge ID.
774   
775    /// The ID of a valid Edge is a nonnegative integer not greater than
776    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
777    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
778    ///
779    /// The ID of the \ref INVALID edge is -1.
780    ///\return The ID of the edge \c e.
781    static int id(Edge e) { return e.id; }
782
783    /// The ID of a valid SymEdge is a nonnegative integer not greater than
784    /// \ref maxSymEdgeId(). The range of the ID's is not surely continuous
785    /// and the greatest edge ID can be actually less then \ref maxSymEdgeId().
786    ///
787    /// The ID of the \ref INVALID symmetric edge is -1.
788    ///\return The ID of the edge \c e.
789    static int id(SymEdge e) { return Parent::id(e); }
790
791    /// Adds a new node to the graph.
792
793    /// \warning It adds the new node to the front of the list.
794    /// (i.e. the lastly added node becomes the first.)
795    Node addNode() {
796      return Parent::addNode();
797    }
798   
799    SymEdge addEdge(Node u, Node v) {
800      SymEdge se = Parent::addEdge(u, v);
801      edge_maps.add(forward(se));
802      edge_maps.add(backward(se));
803      return se;
804    }
805   
806    /// Finds an edge between two nodes.
807
808    /// Finds an edge from node \c u to node \c v.
809    ///
810    /// If \c prev is \ref INVALID (this is the default value), then
811    /// It finds the first edge from \c u to \c v. Otherwise it looks for
812    /// the next edge from \c u to \c v after \c prev.
813    /// \return The found edge or INVALID if there is no such an edge.
814    Edge findEdge(Node u, Node v, Edge prev = INVALID)
815    {     
816      if (prev == INVALID || id(prev) & 1 == 0) {
817        SymEdge se = Parent::findEdge(u, v, SymEdge(prev));
818        if (se != INVALID) return forward(se);
819      } else {
820        SymEdge se = Parent::findEdge(v, u, SymEdge(prev));
821        if (se != INVALID) return backward(se);
822      }
823      return INVALID;
824    }
825
826//     /// Finds an symmetric edge between two nodes.
827
828//     /// Finds an symmetric edge from node \c u to node \c v.
829//     ///
830//     /// If \c prev is \ref INVALID (this is the default value), then
831//     /// It finds the first edge from \c u to \c v. Otherwise it looks for
832//     /// the next edge from \c u to \c v after \c prev.
833//     /// \return The found edge or INVALID if there is no such an edge.
834
835//     SymEdge findEdge(Node u, Node v, SymEdge prev = INVALID)
836//     {     
837//       if (prev == INVALID || id(prev) & 1 == 0) {
838//      SymEdge se = Parent::findEdge(u, v, SymEdge(prev));
839//      if (se != INVALID) return se;
840//       } else {
841//      SymEdge se = Parent::findEdge(v, u, SymEdge(prev));
842//      if (se != INVALID) return se;   
843//       }
844//       return INVALID;
845//     }
846   
847  public:
848
849    void erase(Node n) {     
850      for (OutEdgeIt it(*this, n); it != INVALID; ++it) {
851        edge_maps.erase(it);
852        edge_maps.erase(opposite(it));
853      }
854      Parent::erase(n);
855    }
856   
857    void erase(SymEdge e) {
858      edge_maps.erase(forward(e));
859      edge_maps.erase(backward(e));
860      Parent::erase(e);
861    };
862
863    void clear() {
864      edge_maps.clear();
865      Parent::clear();
866    }
867
868    static Edge opposite(Edge e) {
869      return Edge(id(e) ^ 1);
870    }
871
872    static Edge forward(SymEdge e) {
873      return Edge(id(e) << 1);
874    }
875
876    static Edge backward(SymEdge e) {
877      return Edge((id(e) << 1) | 1);
878    }
879
880  };
881
882  ///A graph class containing only nodes.
883
884  ///This class implements a graph structure without edges.
885  ///The most useful application of this class is to be the node set of an
886  ///\ref EdgeSet class.
887  ///
888  ///It conforms to
889  ///the \ref skeleton::ExtendableGraph "ExtendableGraph" concept
890  ///with the exception that you cannot
891  ///add (or delete) edges. The usual edge iterators are exists, but they are
892  ///always \ref INVALID.
893  ///\sa skeleton::ExtendableGraph
894  ///\sa EdgeSet
895  class NodeSet {
896
897    //Nodes are double linked.
898    //The free nodes are only single linked using the "next" field.
899    struct NodeT
900    {
901      int first_in,first_out;
902      int prev, next;
903      //      NodeT() {}
904    };
905
906    std::vector<NodeT> nodes;
907    //The first node
908    int first_node;
909    //The first free node
910    int first_free_node;
911   
912  public:
913
914    typedef NodeSet Graph;
915   
916    class Node;
917    class Edge;
918
919  public:
920
921    class NodeIt;
922    class EdgeIt;
923    class OutEdgeIt;
924    class InEdgeIt;
925   
926    // Create node map registry.
927    CREATE_NODE_MAP_REGISTRY;
928    // Create node maps.
929    CREATE_NODE_MAP(ArrayMap);
930
931    /// Creating empty map structure for edges.
932    template <typename Value>
933    class EdgeMap {
934    public:
935      EdgeMap(const Graph&) {}
936      EdgeMap(const Graph&, const Value&) {}
937
938      EdgeMap(const EdgeMap&) {}
939      template <typename CMap> EdgeMap(const CMap&) {}
940
941      EdgeMap& operator=(const EdgeMap&) {}
942      template <typename CMap> EdgeMap& operator=(const CMap&) {}
943     
944      class ConstIterator {
945      public:
946        bool operator==(const ConstIterator&) {return true;}
947        bool operator!=(const ConstIterator&) {return false;}
948      };
949
950      typedef ConstIterator Iterator;
951     
952      Iterator begin() { return Iterator();}
953      Iterator end() { return Iterator();}
954
955      ConstIterator begin() const { return ConstIterator();}
956      ConstIterator end() const { return ConstIterator();}
957
958    };
959   
960  public:
961
962    ///Default constructor
963    NodeSet()
964      : nodes(), first_node(-1), first_free_node(-1) {}
965    ///Copy constructor
966    NodeSet(const NodeSet &_g)
967      : nodes(_g.nodes), first_node(_g.first_node),
968        first_free_node(_g.first_free_node) {}
969   
970    ///Number of nodes.
971    int nodeNum() const { return nodes.size(); }
972    ///Number of edges.
973    int edgeNum() const { return 0; }
974
975    /// Maximum node ID.
976   
977    /// Maximum node ID.
978    ///\sa id(Node)
979    int maxNodeId() const { return nodes.size()-1; }
980    /// Maximum edge ID.
981   
982    /// Maximum edge ID.
983    ///\sa id(Edge)
984    int maxEdgeId() const { return 0; }
985
986    Node tail(Edge e) const { return INVALID; }
987    Node head(Edge e) const { return INVALID; }
988
989    NodeIt& first(NodeIt& v) const {
990      v=NodeIt(*this); return v; }
991    EdgeIt& first(EdgeIt& e) const {
992      e=EdgeIt(*this); return e; }
993    OutEdgeIt& first(OutEdgeIt& e, const Node v) const {
994      e=OutEdgeIt(*this,v); return e; }
995    InEdgeIt& first(InEdgeIt& e, const Node v) const {
996      e=InEdgeIt(*this,v); return e; }
997
998    /// Node ID.
999   
1000    /// The ID of a valid Node is a nonnegative integer not greater than
1001    /// \ref maxNodeId(). The range of the ID's is not surely continuous
1002    /// and the greatest node ID can be actually less then \ref maxNodeId().
1003    ///
1004    /// The ID of the \ref INVALID node is -1.
1005    ///\return The ID of the node \c v.
1006    static int id(Node v) { return v.n; }
1007    /// Edge ID.
1008   
1009    /// The ID of a valid Edge is a nonnegative integer not greater than
1010    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
1011    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
1012    ///
1013    /// The ID of the \ref INVALID edge is -1.
1014    ///\return The ID of the edge \c e.
1015    static int id(Edge e) { return -1; }
1016
1017    /// Adds a new node to the graph.
1018
1019    /// \warning It adds the new node to the front of the list.
1020    /// (i.e. the lastly added node becomes the first.)
1021    Node addNode() {
1022      int n;
1023     
1024      if(first_free_node==-1)
1025        {
1026          n = nodes.size();
1027          nodes.push_back(NodeT());
1028        }
1029      else {
1030        n = first_free_node;
1031        first_free_node = nodes[n].next;
1032      }
1033     
1034      nodes[n].next = first_node;
1035      if(first_node != -1) nodes[first_node].prev = n;
1036      first_node = n;
1037      nodes[n].prev = -1;
1038     
1039      nodes[n].first_in = nodes[n].first_out = -1;
1040     
1041      Node nn; nn.n=n;
1042
1043      //Update dynamic maps
1044      node_maps.add(nn);
1045
1046      return nn;
1047    }
1048   
1049    void erase(Node nn) {
1050      int n=nn.n;
1051     
1052      if(nodes[n].next != -1) nodes[nodes[n].next].prev = nodes[n].prev;
1053      if(nodes[n].prev != -1) nodes[nodes[n].prev].next = nodes[n].next;
1054      else first_node = nodes[n].next;
1055     
1056      nodes[n].next = first_free_node;
1057      first_free_node = n;
1058
1059      //Update dynamic maps
1060      node_maps.erase(nn);
1061    }
1062   
1063       
1064    Edge findEdge(Node u,Node v, Edge prev = INVALID)
1065    {
1066      return INVALID;
1067    }
1068   
1069    void clear() {
1070      node_maps.clear();
1071      nodes.clear();
1072      first_node = first_free_node = -1;
1073    }
1074
1075    class Node {
1076      friend class NodeSet;
1077      template <typename T> friend class NodeMap;
1078     
1079      friend class Edge;
1080      friend class OutEdgeIt;
1081      friend class InEdgeIt;
1082
1083    protected:
1084      int n;
1085      friend int NodeSet::id(Node v);
1086      Node(int nn) {n=nn;}
1087    public:
1088      Node() {}
1089      Node (Invalid i) { n=-1; }
1090      bool operator==(const Node i) const {return n==i.n;}
1091      bool operator!=(const Node i) const {return n!=i.n;}
1092      bool operator<(const Node i) const {return n<i.n;}
1093    };
1094   
1095    class NodeIt : public Node {
1096      const NodeSet *G;
1097      friend class NodeSet;
1098    public:
1099      NodeIt() : Node() { }
1100      NodeIt(const NodeSet& _G,Node n) : Node(n), G(&_G) { }
1101      NodeIt(Invalid i) : Node(i) { }
1102      NodeIt(const NodeSet& _G) : Node(_G.first_node), G(&_G) { }
1103      NodeIt &operator++() {
1104        n=G->nodes[n].next;
1105        return *this;
1106      }
1107    };
1108
1109    class Edge {
1110    public:
1111      Edge() { }
1112      Edge (Invalid) { }
1113      bool operator==(const Edge i) const {return true;}
1114      bool operator!=(const Edge i) const {return false;}
1115      bool operator<(const Edge i) const {return false;}
1116    };
1117   
1118    class EdgeIt : public Edge {
1119    public:
1120      EdgeIt(const NodeSet& G) : Edge() { }
1121      EdgeIt(const NodeSet&, Edge) : Edge() { }
1122      EdgeIt (Invalid i) : Edge(i) { }
1123      EdgeIt() : Edge() { }
1124      EdgeIt operator++() { return INVALID; }
1125    };
1126   
1127    class OutEdgeIt : public Edge {
1128      friend class NodeSet;
1129    public:
1130      OutEdgeIt() : Edge() { }
1131      OutEdgeIt(const NodeSet&, Edge) : Edge() { }
1132      OutEdgeIt (Invalid i) : Edge(i) { }
1133      OutEdgeIt(const NodeSet& G,const Node v)  : Edge() {}
1134      OutEdgeIt operator++() { return INVALID; }
1135    };
1136   
1137    class InEdgeIt : public Edge {
1138      friend class NodeSet;
1139    public:
1140      InEdgeIt() : Edge() { }
1141      InEdgeIt(const NodeSet&, Edge) : Edge() { }
1142      InEdgeIt (Invalid i) : Edge(i) { }
1143      InEdgeIt(const NodeSet& G,Node v) :Edge() {}
1144      InEdgeIt operator++() { return INVALID; }
1145    };
1146
1147  };
1148
1149
1150
1151  ///Graph structure using a node set of another graph.
1152
1153  ///This structure can be used to establish another graph over a node set
1154  /// of an existing one. The node iterator will go through the nodes of the
1155  /// original graph, and the NodeMap's of both graphs will convert to
1156  /// each other.
1157  ///
1158  ///\warning Adding or deleting nodes from the graph is not safe if an
1159  ///\ref EdgeSet is currently attached to it!
1160  ///
1161  ///\todo Make it possible to add/delete edges from the base graph
1162  ///(and from \ref EdgeSet, as well)
1163  ///
1164  ///\param GG The type of the graph which shares its node set with this class.
1165  ///Its interface must conform to the
1166  ///\ref skeleton::StaticGraph "StaticGraph" concept.
1167  ///
1168  ///It conforms to the
1169  ///\ref skeleton::ExtendableGraph "ExtendableGraph" concept.
1170  ///\sa skeleton::ExtendableGraph.
1171  ///\sa NodeSet.
1172  template<typename GG>
1173  class EdgeSet {
1174
1175    typedef GG NodeGraphType;
1176
1177    NodeGraphType &G;
1178
1179  public:
1180
1181    class Node;
1182    class Edge;
1183    class OutEdgeIt;
1184    class InEdgeIt;
1185    class SymEdge;
1186
1187    typedef EdgeSet Graph;
1188
1189    int id(Node v) const;
1190
1191    class Node : public NodeGraphType::Node {
1192      friend class EdgeSet;
1193     
1194      friend class Edge;
1195      friend class OutEdgeIt;
1196      friend class InEdgeIt;
1197      friend class SymEdge;
1198
1199    public:
1200      friend int EdgeSet::id(Node v) const;
1201    public:
1202      Node() : NodeGraphType::Node() {}
1203      Node (Invalid i) : NodeGraphType::Node(i) {}
1204      Node(const typename NodeGraphType::Node &n) : NodeGraphType::Node(n) {}
1205    };
1206   
1207    class NodeIt : public NodeGraphType::NodeIt {
1208      friend class EdgeSet;
1209    public:
1210      NodeIt() : NodeGraphType::NodeIt() { }
1211      NodeIt(const EdgeSet& _G,Node n) : NodeGraphType::NodeIt(_G.G,n) { }
1212      NodeIt (Invalid i) : NodeGraphType::NodeIt(i) {}
1213      NodeIt(const EdgeSet& _G) : NodeGraphType::NodeIt(_G.G) { }
1214      NodeIt(const typename NodeGraphType::NodeIt &n)
1215        : NodeGraphType::NodeIt(n) {}
1216
1217      operator Node() { return Node(*this);}
1218      NodeIt &operator++()
1219      { this->NodeGraphType::NodeIt::operator++(); return *this;}
1220    };
1221
1222  private:
1223    //Edges are double linked.
1224    //The free edges are only single linked using the "next_in" field.
1225    struct NodeT
1226    {
1227      int first_in,first_out;
1228      NodeT() : first_in(-1), first_out(-1) { }
1229    };
1230
1231    struct EdgeT
1232    {
1233      Node head, tail;
1234      int prev_in, prev_out;
1235      int next_in, next_out;
1236    };
1237
1238   
1239    typename NodeGraphType::template NodeMap<NodeT> nodes;
1240   
1241    std::vector<EdgeT> edges;
1242    //The first free edge
1243    int first_free_edge;
1244   
1245  public:
1246   
1247    class Node;
1248    class Edge;
1249
1250    class NodeIt;
1251    class EdgeIt;
1252    class OutEdgeIt;
1253    class InEdgeIt;
1254
1255
1256    // Create edge map registry.
1257    CREATE_EDGE_MAP_REGISTRY;
1258    // Create edge maps.
1259    CREATE_EDGE_MAP(ArrayMap);
1260
1261    // Import node maps from the NodeGraphType.
1262    IMPORT_NODE_MAP(NodeGraphType, graph.G, EdgeSet, graph);
1263   
1264   
1265  public:
1266
1267    ///Constructor
1268   
1269    ///Construates a new graph based on the nodeset of an existing one.
1270    ///\param _G the base graph.
1271    explicit EdgeSet(NodeGraphType &_G)
1272      : G(_G), nodes(_G), edges(),
1273        first_free_edge(-1) {}
1274    ///Copy constructor
1275
1276    ///Makes a copy of an EdgeSet.
1277    ///It will be based on the same graph.
1278    explicit EdgeSet(const EdgeSet &_g)
1279      : G(_g.G), nodes(_g.G), edges(_g.edges),
1280        first_free_edge(_g.first_free_edge) {}
1281   
1282    ///Number of nodes.
1283    int nodeNum() const { return G.nodeNum(); }
1284    ///Number of edges.
1285    int edgeNum() const { return edges.size(); }
1286
1287    /// Maximum node ID.
1288   
1289    /// Maximum node ID.
1290    ///\sa id(Node)
1291    int maxNodeId() const { return G.maxNodeId(); }
1292    /// Maximum edge ID.
1293   
1294    /// Maximum edge ID.
1295    ///\sa id(Edge)
1296    int maxEdgeId() const { return edges.size()-1; }
1297
1298    Node tail(Edge e) const { return edges[e.n].tail; }
1299    Node head(Edge e) const { return edges[e.n].head; }
1300
1301    NodeIt& first(NodeIt& v) const {
1302      v=NodeIt(*this); return v; }
1303    EdgeIt& first(EdgeIt& e) const {
1304      e=EdgeIt(*this); return e; }
1305    OutEdgeIt& first(OutEdgeIt& e, const Node v) const {
1306      e=OutEdgeIt(*this,v); return e; }
1307    InEdgeIt& first(InEdgeIt& e, const Node v) const {
1308      e=InEdgeIt(*this,v); return e; }
1309
1310    /// Node ID.
1311   
1312    /// The ID of a valid Node is a nonnegative integer not greater than
1313    /// \ref maxNodeId(). The range of the ID's is not surely continuous
1314    /// and the greatest node ID can be actually less then \ref maxNodeId().
1315    ///
1316    /// The ID of the \ref INVALID node is -1.
1317    ///\return The ID of the node \c v.
1318    int id(Node v) { return G.id(v); }
1319    /// Edge ID.
1320   
1321    /// The ID of a valid Edge is a nonnegative integer not greater than
1322    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
1323    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
1324    ///
1325    /// The ID of the \ref INVALID edge is -1.
1326    ///\return The ID of the edge \c e.
1327    static int id(Edge e) { return e.n; }
1328
1329    /// Adds a new node to the graph.
1330    Node addNode() { return G.addNode(); }
1331   
1332    Edge addEdge(Node u, Node v) {
1333      int n;
1334     
1335      if(first_free_edge==-1)
1336        {
1337          n = edges.size();
1338          edges.push_back(EdgeT());
1339        }
1340      else {
1341        n = first_free_edge;
1342        first_free_edge = edges[n].next_in;
1343      }
1344     
1345      edges[n].tail = u; edges[n].head = v;
1346
1347      edges[n].next_out = nodes[u].first_out;
1348      if(nodes[u].first_out != -1) edges[nodes[u].first_out].prev_out = n;
1349      edges[n].next_in = nodes[v].first_in;
1350      if(nodes[v].first_in != -1) edges[nodes[v].first_in].prev_in = n;
1351      edges[n].prev_in = edges[n].prev_out = -1;
1352       
1353      nodes[u].first_out = nodes[v].first_in = n;
1354
1355      Edge e; e.n=n;
1356
1357      //Update dynamic maps
1358      edge_maps.add(e);
1359
1360      return e;
1361    }
1362
1363    /// Finds an edge between two nodes.
1364
1365    /// Finds an edge from node \c u to node \c v.
1366    ///
1367    /// If \c prev is \ref INVALID (this is the default value), then
1368    /// It finds the first edge from \c u to \c v. Otherwise it looks for
1369    /// the next edge from \c u to \c v after \c prev.
1370    /// \return The found edge or INVALID if there is no such an edge.
1371    Edge findEdge(Node u,Node v, Edge prev = INVALID)
1372    {
1373      int e = (prev.n==-1)? nodes[u].first_out : edges[prev.n].next_out;
1374      while(e!=-1 && edges[e].tail!=v) e = edges[e].next_out;
1375      prev.n=e;
1376      return prev;
1377    }
1378   
1379  private:
1380    void eraseEdge(int n) {
1381     
1382      if(edges[n].next_in!=-1)
1383        edges[edges[n].next_in].prev_in = edges[n].prev_in;
1384      if(edges[n].prev_in!=-1)
1385        edges[edges[n].prev_in].next_in = edges[n].next_in;
1386      else nodes[edges[n].head].first_in = edges[n].next_in;
1387     
1388      if(edges[n].next_out!=-1)
1389        edges[edges[n].next_out].prev_out = edges[n].prev_out;
1390      if(edges[n].prev_out!=-1)
1391        edges[edges[n].prev_out].next_out = edges[n].next_out;
1392      else nodes[edges[n].tail].first_out = edges[n].next_out;
1393     
1394      edges[n].next_in = first_free_edge;
1395      first_free_edge = -1;     
1396
1397      //Update dynamic maps
1398      Edge e; e.n = n;
1399      edge_maps.erase(e);
1400    }
1401     
1402  public:
1403
1404    void erase(Edge e) { eraseEdge(e.n); }
1405
1406    ///Clear all edges. (Doesn't clear the nodes!)
1407    void clear() {
1408      edge_maps.clear();
1409      edges.clear();
1410      first_free_edge=-1;
1411    }
1412
1413
1414    class Edge {
1415    public:
1416      friend class EdgeSet;
1417      template <typename T> friend class EdgeMap;
1418
1419      friend class Node;
1420      friend class NodeIt;
1421    protected:
1422      int n;
1423      friend int EdgeSet::id(Edge e) const;
1424
1425      Edge(int nn) {n=nn;}
1426    public:
1427      Edge() { }
1428      Edge (Invalid) { n=-1; }
1429      bool operator==(const Edge i) const {return n==i.n;}
1430      bool operator!=(const Edge i) const {return n!=i.n;}
1431      bool operator<(const Edge i) const {return n<i.n;}
1432    };
1433   
1434    class EdgeIt : public Edge {
1435      friend class EdgeSet;
1436      template <typename T> friend class EdgeMap;
1437   
1438      const EdgeSet *G;
1439    public:
1440      EdgeIt(const EdgeSet& _G) : Edge(), G(&_G) {
1441        NodeIt m;
1442        for(G->first(m);
1443            m!=INVALID && G->nodes[m].first_in == -1;  ++m);
1444        ///\bug AJJAJ! This is a non sense!!!!!!!
1445        this->n = m!=INVALID?-1:G->nodes[m].first_in;
1446      }
1447      EdgeIt(const EdgeSet& _G, Edge e) : Edge(e), G(&_G) { }
1448      EdgeIt (Invalid i) : Edge(i) { }
1449      EdgeIt() : Edge() { }
1450      ///.
1451     
1452      ///\bug UNIMPLEMENTED!!!!!
1453      //
1454      EdgeIt &operator++() {
1455        return *this;
1456      }
1457    };
1458   
1459    class OutEdgeIt : public Edge {
1460      const EdgeSet *G;
1461      friend class EdgeSet;
1462    public:
1463      OutEdgeIt() : Edge() { }
1464      OutEdgeIt (Invalid i) : Edge(i) { }
1465      OutEdgeIt(const EdgeSet& _G, Edge e) : Edge(e), G(&_G) { }
1466
1467      OutEdgeIt(const EdgeSet& _G,const Node v) :
1468        Edge(_G.nodes[v].first_out), G(&_G) { }
1469      OutEdgeIt &operator++() {
1470        Edge::n = G->edges[Edge::n].next_out;
1471        return *this;
1472      }
1473    };
1474   
1475    class InEdgeIt : public Edge {
1476      const EdgeSet *G;
1477      friend class EdgeSet;
1478    public:
1479      InEdgeIt() : Edge() { }
1480      InEdgeIt (Invalid i) : Edge(i) { }
1481      InEdgeIt(const EdgeSet& _G, Edge e) : Edge(e), G(&_G) { }
1482      InEdgeIt(const EdgeSet& _G,Node v)
1483        : Edge(_G.nodes[v].first_in), G(&_G) { }
1484      InEdgeIt &operator++() {
1485        Edge::n = G->edges[Edge::n].next_in;
1486        return *this;
1487      }
1488    };
1489   
1490  };
1491
1492  template<typename GG>
1493  inline int EdgeSet<GG>::id(Node v) const { return G.id(v); }
1494
1495/// @} 
1496
1497} //namespace lemon
1498
1499#endif //LEMON_LIST_GRAPH_H
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