COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/list_graph.h @ 1702:44d495c659b5

Last change on this file since 1702:44d495c659b5 was 1702:44d495c659b5, checked in by Balazs Dezso, 14 years ago

Bugfix in list_graph

File size: 15.0 KB
Line 
1/* -*- C++ -*-
2 * lemon/list_graph.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Research Group on Combinatorial Optimization, 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, UndirListGraph classes.
23
24#include <lemon/bits/erasable_graph_extender.h>
25#include <lemon/bits/clearable_graph_extender.h>
26#include <lemon/bits/extendable_graph_extender.h>
27#include <lemon/bits/iterable_graph_extender.h>
28#include <lemon/bits/alteration_notifier.h>
29#include <lemon/bits/default_map.h>
30
31#include <lemon/bits/undir_graph_extender.h>
32
33#include <list>
34
35namespace lemon {
36
37  class ListGraphBase {
38
39  protected:
40    struct NodeT {
41      int first_in, first_out;
42      int prev, next;
43    };
44 
45    struct EdgeT {
46      int target, source;
47      int prev_in, prev_out;
48      int next_in, next_out;
49    };
50
51    std::vector<NodeT> nodes;
52
53    int first_node;
54
55    int first_free_node;
56
57    std::vector<EdgeT> edges;
58
59    int first_free_edge;
60   
61  public:
62   
63    typedef ListGraphBase Graph;
64   
65    class Node {
66      friend class ListGraphBase;
67    protected:
68
69      int id;
70      Node(int pid) { id = pid;}
71
72    public:
73      Node() {}
74      Node (Invalid) { id = -1; }
75      bool operator==(const Node& node) const {return id == node.id;}
76      bool operator!=(const Node& node) const {return id != node.id;}
77      bool operator<(const Node& node) const {return id < node.id;}
78    };
79
80    class Edge {
81      friend class ListGraphBase;
82    protected:
83
84      int id;
85      Edge(int pid) { id = pid;}
86
87    public:
88      Edge() {}
89      Edge (Invalid) { id = -1; }
90      bool operator==(const Edge& edge) const {return id == edge.id;}
91      bool operator!=(const Edge& edge) const {return id != edge.id;}
92      bool operator<(const Edge& edge) const {return id < edge.id;}
93    };
94
95
96
97    ListGraphBase()
98      : nodes(), first_node(-1),
99        first_free_node(-1), edges(), first_free_edge(-1) {}
100
101   
102    /// Maximum node ID.
103   
104    /// Maximum node ID.
105    ///\sa id(Node)
106    int maxId(Node = INVALID) const { return nodes.size()-1; }
107
108    /// Maximum edge ID.
109   
110    /// Maximum edge ID.
111    ///\sa id(Edge)
112    int maxId(Edge = INVALID) const { return edges.size()-1; }
113
114    Node source(Edge e) const { return edges[e.id].source; }
115    Node target(Edge e) const { return edges[e.id].target; }
116
117
118    void first(Node& node) const {
119      node.id = first_node;
120    }
121
122    void next(Node& node) const {
123      node.id = nodes[node.id].next;
124    }
125
126
127    void first(Edge& e) const {
128      int n;
129      for(n = first_node;
130          n!=-1 && nodes[n].first_in == -1;
131          n = nodes[n].next);
132      e.id = (n == -1) ? -1 : nodes[n].first_in;
133    }
134
135    void next(Edge& edge) const {
136      if (edges[edge.id].next_in != -1) {
137        edge.id = edges[edge.id].next_in;
138      } else {
139        int n;
140        for(n = nodes[edges[edge.id].target].next;
141          n!=-1 && nodes[n].first_in == -1;
142          n = nodes[n].next);
143        edge.id = (n == -1) ? -1 : nodes[n].first_in;
144      }     
145    }
146
147    void firstOut(Edge &e, const Node& v) const {
148      e.id = nodes[v.id].first_out;
149    }
150    void nextOut(Edge &e) const {
151      e.id=edges[e.id].next_out;
152    }
153
154    void firstIn(Edge &e, const Node& v) const {
155      e.id = nodes[v.id].first_in;
156    }
157    void nextIn(Edge &e) const {
158      e.id=edges[e.id].next_in;
159    }
160
161   
162    static int id(Node v) { return v.id; }
163    static int id(Edge e) { return e.id; }
164
165    static Node fromId(int id, Node) { return Node(id);}
166    static Edge fromId(int id, Edge) { return Edge(id);}
167
168    /// Adds a new node to the graph.
169
170    /// \warning It adds the new node to the front of the list.
171    /// (i.e. the lastly added node becomes the first.)
172    Node addNode() {     
173      int n;
174     
175      if(first_free_node==-1) {
176        n = nodes.size();
177        nodes.push_back(NodeT());
178      } else {
179        n = first_free_node;
180        first_free_node = nodes[n].next;
181      }
182     
183      nodes[n].next = first_node;
184      if(first_node != -1) nodes[first_node].prev = n;
185      first_node = n;
186      nodes[n].prev = -1;
187     
188      nodes[n].first_in = nodes[n].first_out = -1;
189     
190      return Node(n);
191    }
192   
193    Edge addEdge(Node u, Node v) {
194      int n;     
195
196      if (first_free_edge == -1) {
197        n = edges.size();
198        edges.push_back(EdgeT());
199      } else {
200        n = first_free_edge;
201        first_free_edge = edges[n].next_in;
202      }
203     
204      edges[n].source = u.id;
205      edges[n].target = v.id;
206
207      edges[n].next_out = nodes[u.id].first_out;
208      if(nodes[u.id].first_out != -1) {
209        edges[nodes[u.id].first_out].prev_out = n;
210      }
211     
212      edges[n].next_in = nodes[v.id].first_in;
213      if(nodes[v.id].first_in != -1) {
214        edges[nodes[v.id].first_in].prev_in = n;
215      }
216     
217      edges[n].prev_in = edges[n].prev_out = -1;
218       
219      nodes[u.id].first_out = nodes[v.id].first_in = n;
220
221      return Edge(n);
222    }
223   
224    void erase(const Node& node) {
225      int n = node.id;
226     
227      if(nodes[n].next != -1) {
228        nodes[nodes[n].next].prev = nodes[n].prev;
229      }
230     
231      if(nodes[n].prev != -1) {
232        nodes[nodes[n].prev].next = nodes[n].next;
233      } else {
234        first_node = nodes[n].next;
235      }
236     
237      nodes[n].next = first_free_node;
238      first_free_node = n;
239
240    }
241   
242    void erase(const Edge& edge) {
243      int n = edge.id;
244     
245      if(edges[n].next_in!=-1) {
246        edges[edges[n].next_in].prev_in = edges[n].prev_in;
247      }
248
249      if(edges[n].prev_in!=-1) {
250        edges[edges[n].prev_in].next_in = edges[n].next_in;
251      } else {
252        nodes[edges[n].target].first_in = edges[n].next_in;
253      }
254
255     
256      if(edges[n].next_out!=-1) {
257        edges[edges[n].next_out].prev_out = edges[n].prev_out;
258      }
259
260      if(edges[n].prev_out!=-1) {
261        edges[edges[n].prev_out].next_out = edges[n].next_out;
262      } else {
263        nodes[edges[n].source].first_out = edges[n].next_out;
264      }
265     
266      edges[n].next_in = first_free_edge;
267      first_free_edge = n;     
268
269    }
270
271    void clear() {
272      edges.clear();
273      nodes.clear();
274      first_node = first_free_node = first_free_edge = -1;
275    }
276
277  protected:
278    void _changeTarget(Edge e, Node n)
279    {
280      if(edges[e.id].next_in != -1)
281        edges[edges[e.id].next_in].prev_in = edges[e.id].prev_in;
282      if(edges[e.id].prev_in != -1)
283        edges[edges[e.id].prev_in].next_in = edges[e.id].next_in;
284      else nodes[edges[e.id].target].first_in = edges[e.id].next_in;
285      if (nodes[n.id].first_in != -1) {
286        edges[nodes[n.id].first_in].prev_in = e.id;
287      }
288      edges[e.id].target = n.id;
289      edges[e.id].prev_in = -1;
290      edges[e.id].next_in = nodes[n.id].first_in;
291      nodes[n.id].first_in = e.id;
292    }
293    void _changeSource(Edge e, Node n)
294    {
295      if(edges[e.id].next_out != -1)
296        edges[edges[e.id].next_out].prev_out = edges[e.id].prev_out;
297      if(edges[e.id].prev_out != -1)
298        edges[edges[e.id].prev_out].next_out = edges[e.id].next_out;
299      else nodes[edges[e.id].source].first_out = edges[e.id].next_out;
300      if (nodes[n.id].first_out != -1) {
301        edges[nodes[n.id].first_out].prev_out = e.id;
302      }
303      edges[e.id].source = n.id;
304      edges[e.id].prev_out = -1;
305      edges[e.id].next_out = nodes[n.id].first_out;
306      nodes[n.id].first_out = e.id;
307    }
308
309  };
310
311  typedef AlterableGraphExtender<ListGraphBase> AlterableListGraphBase;
312  typedef IterableGraphExtender<AlterableListGraphBase> IterableListGraphBase;
313  typedef MappableGraphExtender<IterableListGraphBase> MappableListGraphBase;
314  typedef ExtendableGraphExtender<MappableListGraphBase> ExtendableListGraphBase;
315  typedef ClearableGraphExtender<ExtendableListGraphBase> ClearableListGraphBase;
316  typedef ErasableGraphExtender<
317    ClearableGraphExtender<
318    ExtendableGraphExtender<
319    MappableGraphExtender<
320    IterableGraphExtender<
321    AlterableGraphExtender<ListGraphBase> > > > > > ExtendedListGraphBase;
322
323/// \addtogroup graphs
324/// @{
325
326  ///A list graph class.
327
328  ///This is a simple and fast erasable graph implementation.
329  ///
330  ///It addition that it conforms to the
331  ///\ref concept::ErasableGraph "ErasableGraph" concept,
332  ///it also provides several additional useful extra functionalities.
333  ///\sa concept::ErasableGraph.
334
335  class ListGraph : public ExtendedListGraphBase
336  {
337  public:
338    /// Changes the target of \c e to \c n
339
340    /// Changes the target of \c e to \c n
341    ///
342    ///\note The <tt>Edge</tt>'s and <tt>OutEdge</tt>'s
343    ///referencing the changed edge remain
344    ///valid. However <tt>InEdge</tt>'s are invalidated.
345    void changeTarget(Edge e, Node n) { _changeTarget(e,n); }
346    /// Changes the source of \c e to \c n
347
348    /// Changes the source of \c e to \c n
349    ///
350    ///\note The <tt>Edge</tt>'s and <tt>InEdge</tt>'s
351    ///referencing the changed edge remain
352    ///valid. However <tt>OutEdge</tt>'s are invalidated.
353    void changeSource(Edge e, Node n) { _changeSource(e,n); }
354
355    /// Invert the direction of an edge.
356
357    ///\note The <tt>Edge</tt>'s
358    ///referencing the changed edge remain
359    ///valid. However <tt>OutEdge</tt>'s  and <tt>InEdge</tt>'s are invalidated.
360    void reverseEdge(Edge e) {
361      Node t=target(e);
362      _changeTarget(e,source(e));
363      _changeSource(e,t);
364    }
365
366    ///Using this it possible to avoid the superfluous memory allocation.
367
368    ///Using this it possible to avoid the superfluous memory allocation.
369    ///\todo more docs...
370    void reserveEdge(int n) { edges.reserve(n); };
371
372    ///Contract two nodes.
373
374    ///This function contracts two nodes.
375    ///
376    ///Node \p b will be removed but instead of deleting
377    ///its neighboring edges, they will be joined to \p a.
378    ///The last parameter \p r controls whether to remove loops. \c true
379    ///means that loops will be removed.
380    ///
381    ///\note The <tt>Edge</tt>s
382    ///referencing a moved edge remain
383    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
384    ///may be invalidated.
385    void contract(Node a,Node b,bool r=true)
386    {
387      for(OutEdgeIt e(*this,b);e!=INVALID;) {
388        OutEdgeIt f=e;
389        ++f;
390        if(r && target(e)==a) erase(e);
391        else changeSource(e,a);
392        e=f;
393      }
394      for(InEdgeIt e(*this,b);e!=INVALID;) {
395        InEdgeIt f=e;
396        ++f;
397        if(r && source(e)==a) erase(e);
398        else changeTarget(e,a);
399        e=f;
400      }
401      erase(b);
402    }
403
404    ///Split a node.
405
406    ///This function splits a node. First a new node is added to the graph,
407    ///then the source of each outgoing edge of \c n is moved to this new node.
408    ///If \c connect is \c true (this is the default value), then a new edge
409    ///from \c n to the newly created node is also added.
410    ///\return The newly created node.
411    ///
412    ///\note The <tt>Edge</tt>s
413    ///referencing a moved edge remain
414    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
415    ///may be invalidated.
416    ///\warning This functionality cannot be used together with the SnapShot
417    ///feature.
418    ///\todo It could be implemented in a bit faster way.
419    Node split(Node n, bool connect = true)
420    {
421      Node b = addNode();
422      for(OutEdgeIt e(*this,n);e!=INVALID;) {
423        OutEdgeIt f=e;
424        ++f;
425        changeSource(e,b);
426        e=f;
427      }
428      if(connect) addEdge(n,b);
429      return b;
430    }
431     
432    ///Class to make a snapshot of the graph and to restrore to it later.
433
434    ///Class to make a snapshot of the graph and to restrore to it later.
435    ///
436    ///The newly added nodes and edges can be removed using the
437    ///restore() function.
438    ///
439    ///\warning Edge and node deletions cannot be restored.
440    ///\warning SnapShots cannot be nested.
441    ///\todo \c SnapShot or \c Snapshot?
442    class SnapShot : protected AlterationNotifier<Node>::ObserverBase,
443                     protected AlterationNotifier<Edge>::ObserverBase
444    {
445      protected:
446     
447      ListGraph *g;
448      std::list<Node> added_nodes;
449      std::list<Edge> added_edges;
450     
451      bool active;
452      virtual void add(const Node& n) {
453        added_nodes.push_back(n);
454      };
455      ///\bug Exception...
456      ///
457      virtual void erase(const Node&)
458      {
459        exit(1);
460      }
461      virtual void add(const Edge& n) {
462        added_edges.push_back(n);
463      };
464      ///\bug Exception...
465      ///
466      virtual void erase(const Edge&)
467      {
468        exit(1);
469      }
470
471      ///\bug What is this used for?
472      ///
473      virtual void build() {}
474      ///\bug What is this used for?
475      ///
476      virtual void clear() {}
477
478      void regist(ListGraph &_g) {
479        g=&_g;
480        AlterationNotifier<Node>::ObserverBase::
481          attach(g->getNotifier(Node()));
482        AlterationNotifier<Edge>::ObserverBase::
483          attach(g->getNotifier(Edge()));
484      }
485           
486      void deregist() {
487        AlterationNotifier<Node>::ObserverBase::
488          detach();
489        AlterationNotifier<Edge>::ObserverBase::
490          detach();
491        g=0;
492      }
493           
494    public:
495      ///Default constructur.
496     
497      ///Default constructur.
498      ///To actually make a snapshot you must call save().
499      ///
500      SnapShot() : g(0) {}
501      ///Constructor that immediately makes a snapshot.
502     
503      ///This constructor immediately makes a snapshot of the graph.
504      ///\param _g The graph we make a snapshot of.
505      SnapShot(ListGraph &_g) {
506        regist(_g);
507      }
508      ///\bug Is it necessary?
509      ///
510      ~SnapShot()
511      {
512        if(g) deregist();
513      }
514     
515      ///Make a snapshot.
516
517      ///Make a snapshot of the graph.
518      ///
519      ///This function can be called more than once. In case of a repeated
520      ///call, the previous snapshot gets lost.
521      ///\param _g The graph we make the snapshot of.
522      void save(ListGraph &_g)
523      {
524        if(g!=&_g) {
525          if(g) deregist();
526          regist(_g);
527        }
528        added_nodes.clear();
529        added_edges.clear();
530      }
531     
532    ///Undo the changes until the last snapshot.
533
534    ///Undo the changes until last snapshot created by save().
535    ///
536    ///\todo This function might be called undo().
537      void restore() {
538        ListGraph &old_g=*g;
539        deregist();
540        while(!added_edges.empty()) {
541          old_g.erase(added_edges.front());
542          added_edges.pop_front();
543        }
544        while(!added_nodes.empty()) {
545          old_g.erase(added_nodes.front());
546          added_nodes.pop_front();
547        }
548      }
549    };
550   
551  };
552
553  ///@}
554
555  /**************** Undirected List Graph ****************/
556
557  typedef ErasableUndirGraphExtender<
558    ClearableUndirGraphExtender<
559    ExtendableUndirGraphExtender<
560    MappableUndirGraphExtender<
561    IterableUndirGraphExtender<
562    AlterableUndirGraphExtender<
563    UndirGraphExtender<ListGraphBase> > > > > > > ExtendedUndirListGraphBase;
564
565/// \addtogroup graphs
566/// @{
567
568  ///An undirected list graph class.
569
570  ///This is a simple and fast erasable undirected graph implementation.
571  ///
572  ///It conforms to the
573  ///\ref concept::UndirGraph "UndirGraph" concept.
574  ///
575  ///\sa concept::UndirGraph.
576  ///
577  ///\todo SnapShot, reverseEdge(), changeTarget(), changeSource(), contract()
578  ///haven't been implemented yet.
579  ///
580  class UndirListGraph : public ExtendedUndirListGraphBase {
581  };
582
583 
584  /// @} 
585} //namespace lemon
586 
587
588#endif
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