COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/list_graph.h @ 1956:a055123339d5

Last change on this file since 1956:a055123339d5 was 1956:a055123339d5, checked in by Alpar Juttner, 14 years ago

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1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2006
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
8 *
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
12 *
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
15 * purpose.
16 *
17 */
18
19#ifndef LEMON_LIST_GRAPH_H
20#define LEMON_LIST_GRAPH_H
21
22///\ingroup graphs
23///\file
24///\brief ListGraph, ListUGraph classes.
25
26#include <lemon/bits/erasable_graph_extender.h>
27#include <lemon/bits/clearable_graph_extender.h>
28#include <lemon/bits/extendable_graph_extender.h>
29#include <lemon/bits/iterable_graph_extender.h>
30#include <lemon/bits/alteration_notifier.h>
31#include <lemon/bits/default_map.h>
32#include <lemon/bits/graph_extender.h>
33
34#include <lemon/error.h>
35
36#include <list>
37
38namespace lemon {
39
40  class ListGraphBase {
41
42  protected:
43    struct NodeT {
44      int first_in, first_out;
45      int prev, next;
46    };
47 
48    struct EdgeT {
49      int target, source;
50      int prev_in, prev_out;
51      int next_in, next_out;
52    };
53
54    std::vector<NodeT> nodes;
55
56    int first_node;
57
58    int first_free_node;
59
60    std::vector<EdgeT> edges;
61
62    int first_free_edge;
63   
64  public:
65   
66    typedef ListGraphBase Graph;
67   
68    class Node {
69      friend class ListGraphBase;
70    protected:
71
72      int id;
73      Node(int pid) { id = pid;}
74
75    public:
76      Node() {}
77      Node (Invalid) { id = -1; }
78      bool operator==(const Node& node) const {return id == node.id;}
79      bool operator!=(const Node& node) const {return id != node.id;}
80      bool operator<(const Node& node) const {return id < node.id;}
81    };
82
83    class Edge {
84      friend class ListGraphBase;
85    protected:
86
87      int id;
88      Edge(int pid) { id = pid;}
89
90    public:
91      Edge() {}
92      Edge (Invalid) { id = -1; }
93      bool operator==(const Edge& edge) const {return id == edge.id;}
94      bool operator!=(const Edge& edge) const {return id != edge.id;}
95      bool operator<(const Edge& edge) const {return id < edge.id;}
96    };
97
98
99
100    ListGraphBase()
101      : nodes(), first_node(-1),
102        first_free_node(-1), edges(), first_free_edge(-1) {}
103
104   
105    /// Maximum node ID.
106   
107    /// Maximum node ID.
108    ///\sa id(Node)
109    int maxNodeId() const { return nodes.size()-1; }
110
111    /// Maximum edge ID.
112   
113    /// Maximum edge ID.
114    ///\sa id(Edge)
115    int maxEdgeId() const { return edges.size()-1; }
116
117    Node source(Edge e) const { return edges[e.id].source; }
118    Node target(Edge e) const { return edges[e.id].target; }
119
120
121    void first(Node& node) const {
122      node.id = first_node;
123    }
124
125    void next(Node& node) const {
126      node.id = nodes[node.id].next;
127    }
128
129
130    void first(Edge& e) const {
131      int n;
132      for(n = first_node;
133          n!=-1 && nodes[n].first_in == -1;
134          n = nodes[n].next);
135      e.id = (n == -1) ? -1 : nodes[n].first_in;
136    }
137
138    void next(Edge& edge) const {
139      if (edges[edge.id].next_in != -1) {
140        edge.id = edges[edge.id].next_in;
141      } else {
142        int n;
143        for(n = nodes[edges[edge.id].target].next;
144          n!=-1 && nodes[n].first_in == -1;
145          n = nodes[n].next);
146        edge.id = (n == -1) ? -1 : nodes[n].first_in;
147      }     
148    }
149
150    void firstOut(Edge &e, const Node& v) const {
151      e.id = nodes[v.id].first_out;
152    }
153    void nextOut(Edge &e) const {
154      e.id=edges[e.id].next_out;
155    }
156
157    void firstIn(Edge &e, const Node& v) const {
158      e.id = nodes[v.id].first_in;
159    }
160    void nextIn(Edge &e) const {
161      e.id=edges[e.id].next_in;
162    }
163
164   
165    static int id(Node v) { return v.id; }
166    static int id(Edge e) { return e.id; }
167
168    static Node nodeFromId(int id) { return Node(id);}
169    static Edge edgeFromId(int id) { return Edge(id);}
170
171    /// Adds a new node to the graph.
172
173    /// \warning It adds the new node to the front of the list.
174    /// (i.e. the lastly added node becomes the first.)
175    Node addNode() {     
176      int n;
177     
178      if(first_free_node==-1) {
179        n = nodes.size();
180        nodes.push_back(NodeT());
181      } else {
182        n = first_free_node;
183        first_free_node = nodes[n].next;
184      }
185     
186      nodes[n].next = first_node;
187      if(first_node != -1) nodes[first_node].prev = n;
188      first_node = n;
189      nodes[n].prev = -1;
190     
191      nodes[n].first_in = nodes[n].first_out = -1;
192     
193      return Node(n);
194    }
195   
196    Edge addEdge(Node u, Node v) {
197      int n;     
198
199      if (first_free_edge == -1) {
200        n = edges.size();
201        edges.push_back(EdgeT());
202      } else {
203        n = first_free_edge;
204        first_free_edge = edges[n].next_in;
205      }
206     
207      edges[n].source = u.id;
208      edges[n].target = v.id;
209
210      edges[n].next_out = nodes[u.id].first_out;
211      if(nodes[u.id].first_out != -1) {
212        edges[nodes[u.id].first_out].prev_out = n;
213      }
214     
215      edges[n].next_in = nodes[v.id].first_in;
216      if(nodes[v.id].first_in != -1) {
217        edges[nodes[v.id].first_in].prev_in = n;
218      }
219     
220      edges[n].prev_in = edges[n].prev_out = -1;
221       
222      nodes[u.id].first_out = nodes[v.id].first_in = n;
223
224      return Edge(n);
225    }
226   
227    void erase(const Node& node) {
228      int n = node.id;
229     
230      if(nodes[n].next != -1) {
231        nodes[nodes[n].next].prev = nodes[n].prev;
232      }
233     
234      if(nodes[n].prev != -1) {
235        nodes[nodes[n].prev].next = nodes[n].next;
236      } else {
237        first_node = nodes[n].next;
238      }
239     
240      nodes[n].next = first_free_node;
241      first_free_node = n;
242
243    }
244   
245    void erase(const Edge& edge) {
246      int n = edge.id;
247     
248      if(edges[n].next_in!=-1) {
249        edges[edges[n].next_in].prev_in = edges[n].prev_in;
250      }
251
252      if(edges[n].prev_in!=-1) {
253        edges[edges[n].prev_in].next_in = edges[n].next_in;
254      } else {
255        nodes[edges[n].target].first_in = edges[n].next_in;
256      }
257
258     
259      if(edges[n].next_out!=-1) {
260        edges[edges[n].next_out].prev_out = edges[n].prev_out;
261      }
262
263      if(edges[n].prev_out!=-1) {
264        edges[edges[n].prev_out].next_out = edges[n].next_out;
265      } else {
266        nodes[edges[n].source].first_out = edges[n].next_out;
267      }
268     
269      edges[n].next_in = first_free_edge;
270      first_free_edge = n;     
271
272    }
273
274    void clear() {
275      edges.clear();
276      nodes.clear();
277      first_node = first_free_node = first_free_edge = -1;
278    }
279
280  protected:
281    void _changeTarget(Edge e, Node n)
282    {
283      if(edges[e.id].next_in != -1)
284        edges[edges[e.id].next_in].prev_in = edges[e.id].prev_in;
285      if(edges[e.id].prev_in != -1)
286        edges[edges[e.id].prev_in].next_in = edges[e.id].next_in;
287      else nodes[edges[e.id].target].first_in = edges[e.id].next_in;
288      if (nodes[n.id].first_in != -1) {
289        edges[nodes[n.id].first_in].prev_in = e.id;
290      }
291      edges[e.id].target = n.id;
292      edges[e.id].prev_in = -1;
293      edges[e.id].next_in = nodes[n.id].first_in;
294      nodes[n.id].first_in = e.id;
295    }
296    void _changeSource(Edge e, Node n)
297    {
298      if(edges[e.id].next_out != -1)
299        edges[edges[e.id].next_out].prev_out = edges[e.id].prev_out;
300      if(edges[e.id].prev_out != -1)
301        edges[edges[e.id].prev_out].next_out = edges[e.id].next_out;
302      else nodes[edges[e.id].source].first_out = edges[e.id].next_out;
303      if (nodes[n.id].first_out != -1) {
304        edges[nodes[n.id].first_out].prev_out = e.id;
305      }
306      edges[e.id].source = n.id;
307      edges[e.id].prev_out = -1;
308      edges[e.id].next_out = nodes[n.id].first_out;
309      nodes[n.id].first_out = e.id;
310    }
311
312  };
313
314  typedef ErasableGraphExtender<
315    ClearableGraphExtender<
316    ExtendableGraphExtender<
317    MappableGraphExtender<
318    IterableGraphExtender<
319    AlterableGraphExtender<
320    GraphExtender<ListGraphBase> > > > > > > ExtendedListGraphBase;
321
322  /// \addtogroup graphs
323  /// @{
324
325  ///A list graph class.
326
327  ///This is a simple and fast erasable graph implementation.
328  ///
329  ///It addition that it conforms to the
330  ///\ref concept::ErasableGraph "ErasableGraph" concept,
331  ///it also provides several additional useful extra functionalities.
332  ///\sa concept::ErasableGraph.
333
334  class ListGraph : public ExtendedListGraphBase
335  {
336  public:
337    /// Changes the target of \c e to \c n
338
339    /// Changes the target of \c e to \c n
340    ///
341    ///\note The <tt>Edge</tt>'s and <tt>OutEdge</tt>'s
342    ///referencing the changed edge remain
343    ///valid. However <tt>InEdge</tt>'s are invalidated.
344    void changeTarget(Edge e, Node n) {
345      _changeTarget(e,n);
346    }
347    /// Changes the source of \c e to \c n
348
349    /// Changes the source of \c e to \c n
350    ///
351    ///\note The <tt>Edge</tt>'s and <tt>InEdge</tt>'s
352    ///referencing the changed edge remain
353    ///valid. However <tt>OutEdge</tt>'s are invalidated.
354    void changeSource(Edge e, Node n) {
355      _changeSource(e,n);
356    }
357
358    /// Invert the direction of an edge.
359
360    ///\note The <tt>Edge</tt>'s
361    ///referencing the changed edge remain
362    ///valid. However <tt>OutEdge</tt>'s  and <tt>InEdge</tt>'s are invalidated.
363    void reverseEdge(Edge e) {
364      Node t=target(e);
365      _changeTarget(e,source(e));
366      _changeSource(e,t);
367    }
368
369    ///Using this it possible to avoid the superfluous memory allocation.
370
371    ///Using this it possible to avoid the superfluous memory allocation.
372    ///\todo more docs...
373    void reserveEdge(int n) { edges.reserve(n); };
374
375    ///Contract two nodes.
376
377    ///This function contracts two nodes.
378    ///
379    ///Node \p b will be removed but instead of deleting
380    ///its neighboring edges, they will be joined to \p a.
381    ///The last parameter \p r controls whether to remove loops. \c true
382    ///means that loops will be removed.
383    ///
384    ///\note The <tt>Edge</tt>s
385    ///referencing a moved edge remain
386    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
387    ///may be invalidated.
388    void contract(Node a, Node b, bool r = true)
389    {
390      for(OutEdgeIt e(*this,b);e!=INVALID;) {
391        OutEdgeIt f=e;
392        ++f;
393        if(r && target(e)==a) erase(e);
394        else changeSource(e,a);
395        e=f;
396      }
397      for(InEdgeIt e(*this,b);e!=INVALID;) {
398        InEdgeIt f=e;
399        ++f;
400        if(r && source(e)==a) erase(e);
401        else changeTarget(e,a);
402        e=f;
403      }
404      erase(b);
405    }
406
407    ///Split a node.
408
409    ///This function splits a node. First a new node is added to the graph,
410    ///then the source of each outgoing edge of \c n is moved to this new node.
411    ///If \c connect is \c true (this is the default value), then a new edge
412    ///from \c n to the newly created node is also added.
413    ///\return The newly created node.
414    ///
415    ///\note The <tt>Edge</tt>s
416    ///referencing a moved edge remain
417    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
418    ///may be invalidated.
419    ///\warning This functionality cannot be used together with the Snapshot
420    ///feature.
421    ///\todo It could be implemented in a bit faster way.
422    Node split(Node n, bool connect = true)
423    {
424      Node b = addNode();
425      for(OutEdgeIt e(*this,n);e!=INVALID;) {
426        OutEdgeIt f=e;
427        ++f;
428        changeSource(e,b);
429        e=f;
430      }
431      if(connect) addEdge(n,b);
432      return b;
433    }
434     
435    ///Split an edge.
436
437    ///This function splits an edge. First a new node \c b is added to the graph,
438    ///then the original edge is re-targetes to \c b. Finally an edge
439    ///from \c b to the original target is added.
440    ///\return The newly created node.
441    ///\warning This functionality cannot be used together with the Snapshot
442    ///feature.
443    Node split(Edge e)
444    {
445      Node b = addNode();
446      addEdge(b,target(e));
447      changeTarget(e,b);
448      return b;
449    }
450     
451    ///Class to make a snapshot of the graph and to restrore to it later.
452
453    ///Class to make a snapshot of the graph and to restrore to it later.
454    ///
455    ///The newly added nodes and edges can be removed using the
456    ///restore() function.
457    ///
458    ///\warning Edge and node deletions cannot be restored.
459    ///\warning Snapshots cannot be nested.
460    class Snapshot : protected AlterationNotifier<Node>::ObserverBase,
461                     protected AlterationNotifier<Edge>::ObserverBase
462    {
463    public:
464     
465      class UnsupportedOperation : public LogicError {
466      public:
467        virtual const char* exceptionName() const {
468          return "lemon::ListGraph::Snapshot::UnsupportedOperation";
469        }
470      };
471           
472
473      protected:
474     
475      ListGraph *g;
476      std::list<Node> added_nodes;
477      std::list<Edge> added_edges;
478     
479      bool active;
480      virtual void add(const Node& n) {
481        added_nodes.push_back(n);
482      };
483      virtual void erase(const Node&)
484      {
485        throw UnsupportedOperation();
486      }
487      virtual void add(const Edge& n) {
488        added_edges.push_back(n);
489      };
490      virtual void erase(const Edge&)
491      {
492        throw UnsupportedOperation();
493      }
494
495      ///\bug What is this used for?
496      ///
497      virtual void build() {}
498      ///\bug What is this used for?
499      ///
500      virtual void clear() {}
501
502      void regist(ListGraph &_g) {
503        g=&_g;
504        AlterationNotifier<Node>::ObserverBase::
505          attach(g->getNotifier(Node()));
506        AlterationNotifier<Edge>::ObserverBase::
507          attach(g->getNotifier(Edge()));
508      }
509           
510      void deregist() {
511        AlterationNotifier<Node>::ObserverBase::
512          detach();
513        AlterationNotifier<Edge>::ObserverBase::
514          detach();
515        g=0;
516      }
517
518    public:
519      ///Default constructur.
520     
521      ///Default constructur.
522      ///To actually make a snapshot you must call save().
523      ///
524      Snapshot() : g(0) {}
525      ///Constructor that immediately makes a snapshot.
526     
527      ///This constructor immediately makes a snapshot of the graph.
528      ///\param _g The graph we make a snapshot of.
529      Snapshot(ListGraph &_g) {
530        regist(_g);
531      }
532      ///\bug Is it necessary?
533      ///
534      ~Snapshot()
535      {
536        if(g) deregist();
537      }
538     
539      ///Make a snapshot.
540
541      ///Make a snapshot of the graph.
542      ///
543      ///This function can be called more than once. In case of a repeated
544      ///call, the previous snapshot gets lost.
545      ///\param _g The graph we make the snapshot of.
546      void save(ListGraph &_g)
547      {
548        if(g!=&_g) {
549          if(g) deregist();
550          regist(_g);
551        }
552        added_nodes.clear();
553        added_edges.clear();
554      }
555     
556    ///Undo the changes until the last snapshot.
557
558    ///Undo the changes until last snapshot created by save().
559    ///
560    ///\todo This function might be called undo().
561      void restore() {
562        ListGraph &old_g=*g;
563        deregist();
564        while(!added_edges.empty()) {
565          old_g.erase(added_edges.front());
566          added_edges.pop_front();
567        }
568        while(!added_nodes.empty()) {
569          old_g.erase(added_nodes.front());
570          added_nodes.pop_front();
571        }
572      }
573    };
574   
575  };
576
577  ///@}
578
579  /**************** Undirected List Graph ****************/
580
581  typedef ErasableUGraphExtender<
582    ClearableUGraphExtender<
583    ExtendableUGraphExtender<
584    MappableUGraphExtender<
585    IterableUGraphExtender<
586    AlterableUGraphExtender<
587    UGraphExtender<ListGraphBase> > > > > > > ExtendedListUGraphBase;
588
589  /// \addtogroup graphs
590  /// @{
591
592  ///An undirected list graph class.
593
594  ///This is a simple and fast erasable undirected graph implementation.
595  ///
596  ///It conforms to the
597  ///\ref concept::UGraph "UGraph" concept.
598  ///
599  ///\sa concept::UGraph.
600  ///
601  ///\todo Snapshot, reverseEdge(), changeTarget(), changeSource(), contract()
602  ///haven't been implemented yet.
603  ///
604  class ListUGraph : public ExtendedListUGraphBase {
605  public:
606    typedef ExtendedListUGraphBase Parent;
607    /// \brief Changes the target of \c e to \c n
608    ///
609    /// Changes the target of \c e to \c n
610    ///
611    /// \note The <tt>Edge</tt>'s and <tt>OutEdge</tt>'s
612    /// referencing the changed edge remain
613    /// valid. However <tt>InEdge</tt>'s are invalidated.
614    void changeTarget(UEdge e, Node n) {
615      _changeTarget(e,n);
616    }
617    /// Changes the source of \c e to \c n
618    ///
619    /// Changes the source of \c e to \c n
620    ///
621    ///\note The <tt>Edge</tt>'s and <tt>InEdge</tt>'s
622    ///referencing the changed edge remain
623    ///valid. However <tt>OutEdge</tt>'s are invalidated.
624    void changeSource(UEdge e, Node n) {
625      _changeSource(e,n);
626    }
627    /// \brief Contract two nodes.
628    ///
629    /// This function contracts two nodes.
630    ///
631    /// Node \p b will be removed but instead of deleting
632    /// its neighboring edges, they will be joined to \p a.
633    /// The last parameter \p r controls whether to remove loops. \c true
634    /// means that loops will be removed.
635    ///
636    /// \note The <tt>Edge</tt>s
637    /// referencing a moved edge remain
638    /// valid.
639    void contract(Node a, Node b, bool r = true) {
640      for(IncEdgeIt e(*this, b); e!=INVALID;) {
641        IncEdgeIt f = e; ++f;
642        if (r && runningNode(e) == a) {
643          erase(e);
644        } else if (source(e) == b) {
645          changeSource(e, a);
646        } else {
647          changeTarget(e, a);
648        }
649        e = f;
650      }
651      erase(b);
652    }
653  };
654
655 
656  /// @} 
657} //namespace lemon
658 
659
660#endif
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