COIN-OR::LEMON - Graph Library

source: lemon/lemon/smart_graph.h @ 125:19e82bda606a

Last change on this file since 125:19e82bda606a was 125:19e82bda606a, checked in by Balazs Dezso <deba@…>, 12 years ago

Fix bug #83 in graph concept, extender and smart graph

File size: 19.5 KB
Line 
1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2008
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_SMART_GRAPH_H
20#define LEMON_SMART_GRAPH_H
21
22///\ingroup graphs
23///\file
24///\brief SmartDigraph and SmartGraph classes.
25
26#include <vector>
27
28#include <lemon/bits/invalid.h>
29
30#include <lemon/bits/base_extender.h>
31#include <lemon/bits/graph_extender.h>
32
33#include <lemon/bits/utility.h>
34#include <lemon/error.h>
35
36#include <lemon/bits/graph_extender.h>
37
38namespace lemon {
39
40  class SmartDigraph;
41  ///Base of SmartDigraph
42
43  ///Base of SmartDigraph
44  ///
45  class SmartDigraphBase {
46  protected:
47
48    struct NodeT
49    {
50      int first_in, first_out;     
51      NodeT() {}
52    };
53    struct ArcT
54    {
55      int target, source, next_in, next_out;     
56      ArcT() {} 
57    };
58
59    std::vector<NodeT> nodes;
60    std::vector<ArcT> arcs;
61       
62  public:
63
64    typedef SmartDigraphBase Graph;
65
66    class Node;
67    class Arc;
68
69  public:
70
71    SmartDigraphBase() : nodes(), arcs() { }
72    SmartDigraphBase(const SmartDigraphBase &_g)
73      : nodes(_g.nodes), arcs(_g.arcs) { }
74   
75    typedef True NodeNumTag;
76    typedef True ArcNumTag;
77
78    int nodeNum() const { return nodes.size(); }
79    int arcNum() const { return arcs.size(); }
80
81    int maxNodeId() const { return nodes.size()-1; }
82    int maxArcId() const { return arcs.size()-1; }
83
84    Node addNode() {
85      int n = nodes.size();     
86      nodes.push_back(NodeT());
87      nodes[n].first_in = -1;
88      nodes[n].first_out = -1;
89      return Node(n);
90    }
91   
92    Arc addArc(Node u, Node v) {
93      int n = arcs.size();
94      arcs.push_back(ArcT());
95      arcs[n].source = u._id;
96      arcs[n].target = v._id;
97      arcs[n].next_out = nodes[u._id].first_out;
98      arcs[n].next_in = nodes[v._id].first_in;
99      nodes[u._id].first_out = nodes[v._id].first_in = n;
100
101      return Arc(n);
102    }
103
104    void clear() {
105      arcs.clear();
106      nodes.clear();
107    }
108
109    Node source(Arc a) const { return Node(arcs[a._id].source); }
110    Node target(Arc a) const { return Node(arcs[a._id].target); }
111
112    static int id(Node v) { return v._id; }
113    static int id(Arc a) { return a._id; }
114
115    static Node nodeFromId(int id) { return Node(id);}
116    static Arc arcFromId(int id) { return Arc(id);}
117
118    class Node {
119      friend class SmartDigraphBase;
120      friend class SmartDigraph;
121
122    protected:
123      int _id;
124      explicit Node(int id) : _id(id) {}
125    public:
126      Node() {}
127      Node (Invalid) : _id(-1) {}
128      bool operator==(const Node i) const {return _id == i._id;}
129      bool operator!=(const Node i) const {return _id != i._id;}
130      bool operator<(const Node i) const {return _id < i._id;}
131    };
132   
133
134    class Arc {
135      friend class SmartDigraphBase;
136      friend class SmartDigraph;
137
138    protected:
139      int _id;
140      explicit Arc(int id) : _id(id) {}
141    public:
142      Arc() { }
143      Arc (Invalid) : _id(-1) {}
144      bool operator==(const Arc i) const {return _id == i._id;}
145      bool operator!=(const Arc i) const {return _id != i._id;}
146      bool operator<(const Arc i) const {return _id < i._id;}
147    };
148
149    void first(Node& node) const {
150      node._id = nodes.size() - 1;
151    }
152
153    static void next(Node& node) {
154      --node._id;
155    }
156
157    void first(Arc& arc) const {
158      arc._id = arcs.size() - 1;
159    }
160
161    static void next(Arc& arc) {
162      --arc._id;
163    }
164
165    void firstOut(Arc& arc, const Node& node) const {
166      arc._id = nodes[node._id].first_out;
167    }
168
169    void nextOut(Arc& arc) const {
170      arc._id = arcs[arc._id].next_out;
171    }
172
173    void firstIn(Arc& arc, const Node& node) const {
174      arc._id = nodes[node._id].first_in;
175    }
176   
177    void nextIn(Arc& arc) const {
178      arc._id = arcs[arc._id].next_in;
179    }
180
181  };
182
183  typedef DigraphExtender<SmartDigraphBase> ExtendedSmartDigraphBase;
184
185  ///\ingroup graphs
186  ///
187  ///\brief A smart directed graph class.
188  ///
189  ///This is a simple and fast digraph implementation.
190  ///It is also quite memory efficient, but at the price
191  ///that <b> it does support only limited (only stack-like)
192  ///node and arc deletions</b>.
193  ///It conforms to the \ref concepts::Digraph "Digraph concept" with
194  ///an important extra feature that its maps are real \ref
195  ///concepts::ReferenceMap "reference map"s.
196  ///
197  ///\sa concepts::Digraph.
198  ///
199  ///\author Alpar Juttner
200  class SmartDigraph : public ExtendedSmartDigraphBase {
201  public:
202
203    typedef ExtendedSmartDigraphBase Parent;
204
205  private:
206
207    ///SmartDigraph is \e not copy constructible. Use DigraphCopy() instead.
208
209    ///SmartDigraph is \e not copy constructible. Use DigraphCopy() instead.
210    ///
211    SmartDigraph(const SmartDigraph &) : ExtendedSmartDigraphBase() {};
212    ///\brief Assignment of SmartDigraph to another one is \e not allowed.
213    ///Use DigraphCopy() instead.
214
215    ///Assignment of SmartDigraph to another one is \e not allowed.
216    ///Use DigraphCopy() instead.
217    void operator=(const SmartDigraph &) {}
218
219  public:
220   
221    /// Constructor
222   
223    /// Constructor.
224    ///
225    SmartDigraph() {};
226   
227    ///Add a new node to the digraph.
228   
229    /// \return the new node.
230    ///
231    Node addNode() { return Parent::addNode(); }
232   
233    ///Add a new arc to the digraph.
234   
235    ///Add a new arc to the digraph with source node \c s
236    ///and target node \c t.
237    ///\return the new arc.
238    Arc addArc(const Node& s, const Node& t) {
239      return Parent::addArc(s, t);
240    }
241
242    /// \brief Using this it is possible to avoid the superfluous memory
243    /// allocation.
244
245    /// Using this it is possible to avoid the superfluous memory
246    /// allocation: if you know that the digraph you want to build will
247    /// be very large (e.g. it will contain millions of nodes and/or arcs)
248    /// then it is worth reserving space for this amount before starting
249    /// to build the digraph.
250    /// \sa reserveArc
251    void reserveNode(int n) { nodes.reserve(n); };
252
253    /// \brief Using this it is possible to avoid the superfluous memory
254    /// allocation.
255
256    /// Using this it is possible to avoid the superfluous memory
257    /// allocation: if you know that the digraph you want to build will
258    /// be very large (e.g. it will contain millions of nodes and/or arcs)
259    /// then it is worth reserving space for this amount before starting
260    /// to build the digraph.
261    /// \sa reserveNode
262    void reserveArc(int m) { arcs.reserve(m); };
263
264    ///Clear the digraph.
265   
266    ///Erase all the nodes and arcs from the digraph.
267    ///
268    void clear() {
269      Parent::clear();
270    }
271
272    ///Split a node.
273   
274    ///This function splits a node. First a new node is added to the digraph,
275    ///then the source of each outgoing arc of \c n is moved to this new node.
276    ///If \c connect is \c true (this is the default value), then a new arc
277    ///from \c n to the newly created node is also added.
278    ///\return The newly created node.
279    ///
280    ///\note The <tt>Arc</tt>s
281    ///referencing a moved arc remain
282    ///valid. However <tt>InArc</tt>'s and <tt>OutArc</tt>'s
283    ///may be invalidated.
284    ///\warning This functionality cannot be used together with the Snapshot
285    ///feature.
286    ///\todo It could be implemented in a bit faster way.
287    Node split(Node n, bool connect = true)
288    {
289      Node b = addNode();
290      nodes[b._id].first_out=nodes[n._id].first_out;
291      nodes[n._id].first_out=-1;
292      for(int i=nodes[b._id].first_out;i!=-1;i++) arcs[i].source=b._id;
293      if(connect) addArc(n,b);
294      return b;
295    }
296
297  public:
298   
299    class Snapshot;
300
301  protected:
302
303    void restoreSnapshot(const Snapshot &s)
304    {
305      while(s.arc_num<arcs.size()) {
306        Arc arc = arcFromId(arcs.size()-1);
307        Parent::notifier(Arc()).erase(arc);
308        nodes[arcs.back().source].first_out=arcs.back().next_out;
309        nodes[arcs.back().target].first_in=arcs.back().next_in;
310        arcs.pop_back();
311      }
312      while(s.node_num<nodes.size()) {
313        Node node = nodeFromId(nodes.size()-1);
314        Parent::notifier(Node()).erase(node);
315        nodes.pop_back();
316      }
317    }   
318
319  public:
320
321    ///Class to make a snapshot of the digraph and to restrore to it later.
322
323    ///Class to make a snapshot of the digraph and to restrore to it later.
324    ///
325    ///The newly added nodes and arcs can be removed using the
326    ///restore() function.
327    ///\note After you restore a state, you cannot restore
328    ///a later state, in other word you cannot add again the arcs deleted
329    ///by restore() using another one Snapshot instance.
330    ///
331    ///\warning If you do not use correctly the snapshot that can cause
332    ///either broken program, invalid state of the digraph, valid but
333    ///not the restored digraph or no change. Because the runtime performance
334    ///the validity of the snapshot is not stored.
335    class Snapshot
336    {
337      SmartDigraph *_graph;
338    protected:
339      friend class SmartDigraph;
340      unsigned int node_num;
341      unsigned int arc_num;
342    public:
343      ///Default constructor.
344     
345      ///Default constructor.
346      ///To actually make a snapshot you must call save().
347      ///
348      Snapshot() : _graph(0) {}
349      ///Constructor that immediately makes a snapshot
350     
351      ///This constructor immediately makes a snapshot of the digraph.
352      ///\param _g The digraph we make a snapshot of.
353      Snapshot(SmartDigraph &graph) : _graph(&graph) {
354        node_num=_graph->nodes.size();
355        arc_num=_graph->arcs.size();
356      }
357
358      ///Make a snapshot.
359
360      ///Make a snapshot of the digraph.
361      ///
362      ///This function can be called more than once. In case of a repeated
363      ///call, the previous snapshot gets lost.
364      ///\param _g The digraph we make the snapshot of.
365      void save(SmartDigraph &graph)
366      {
367        _graph=&graph;
368        node_num=_graph->nodes.size();
369        arc_num=_graph->arcs.size();
370      }
371
372      ///Undo the changes until a snapshot.
373     
374      ///Undo the changes until a snapshot created by save().
375      ///
376      ///\note After you restored a state, you cannot restore
377      ///a later state, in other word you cannot add again the arcs deleted
378      ///by restore().
379      void restore()
380      {
381        _graph->restoreSnapshot(*this);
382      }
383    };
384  };
385
386
387  class SmartGraphBase {
388
389  protected:
390
391    struct NodeT {
392      int first_out;
393    };
394 
395    struct ArcT {
396      int target;
397      int next_out;
398    };
399
400    std::vector<NodeT> nodes;
401    std::vector<ArcT> arcs;
402
403    int first_free_arc;
404   
405  public:
406   
407    typedef SmartGraphBase Digraph;
408
409    class Node;
410    class Arc;
411    class Edge;
412   
413    class Node {
414      friend class SmartGraphBase;
415    protected:
416
417      int _id;
418      explicit Node(int id) { _id = id;}
419
420    public:
421      Node() {}
422      Node (Invalid) { _id = -1; }
423      bool operator==(const Node& node) const {return _id == node._id;}
424      bool operator!=(const Node& node) const {return _id != node._id;}
425      bool operator<(const Node& node) const {return _id < node._id;}
426    };
427
428    class Edge {
429      friend class SmartGraphBase;
430    protected:
431
432      int _id;
433      explicit Edge(int id) { _id = id;}
434
435    public:
436      Edge() {}
437      Edge (Invalid) { _id = -1; }
438      bool operator==(const Edge& arc) const {return _id == arc._id;}
439      bool operator!=(const Edge& arc) const {return _id != arc._id;}
440      bool operator<(const Edge& arc) const {return _id < arc._id;}
441    };
442
443    class Arc {
444      friend class SmartGraphBase;
445    protected:
446
447      int _id;
448      explicit Arc(int id) { _id = id;}
449
450    public:
451      operator Edge() const { return edgeFromId(_id / 2); }
452
453      Arc() {}
454      Arc (Invalid) { _id = -1; }
455      bool operator==(const Arc& arc) const {return _id == arc._id;}
456      bool operator!=(const Arc& arc) const {return _id != arc._id;}
457      bool operator<(const Arc& arc) const {return _id < arc._id;}
458    };
459
460
461
462    SmartGraphBase()
463      : nodes(), arcs() {}
464
465   
466    int maxNodeId() const { return nodes.size()-1; }
467    int maxEdgeId() const { return arcs.size() / 2 - 1; }
468    int maxArcId() const { return arcs.size()-1; }
469
470    Node source(Arc e) const { return Node(arcs[e._id ^ 1].target); }
471    Node target(Arc e) const { return Node(arcs[e._id].target); }
472
473    Node u(Edge e) const { return Node(arcs[2 * e._id].target); }
474    Node v(Edge e) const { return Node(arcs[2 * e._id + 1].target); }
475
476    static bool direction(Arc e) {
477      return (e._id & 1) == 1;
478    }
479
480    static Arc direct(Edge e, bool d) {
481      return Arc(e._id * 2 + (d ? 1 : 0));
482    }
483
484    void first(Node& node) const {
485      node._id = nodes.size() - 1;
486    }
487
488    void next(Node& node) const {
489      --node._id;
490    }
491
492    void first(Arc& arc) const {
493      arc._id = arcs.size() - 1;
494    }
495
496    void next(Arc& arc) const {
497      --arc._id;
498    }
499
500    void first(Edge& arc) const {
501      arc._id = arcs.size() / 2 - 1;
502    }
503
504    void next(Edge& arc) const {
505      --arc._id;
506    }
507
508    void firstOut(Arc &arc, const Node& v) const {
509      arc._id = nodes[v._id].first_out;
510    }
511    void nextOut(Arc &arc) const {
512      arc._id = arcs[arc._id].next_out;
513    }
514
515    void firstIn(Arc &arc, const Node& v) const {
516      arc._id = ((nodes[v._id].first_out) ^ 1);
517      if (arc._id == -2) arc._id = -1;
518    }
519    void nextIn(Arc &arc) const {
520      arc._id = ((arcs[arc._id ^ 1].next_out) ^ 1);
521      if (arc._id == -2) arc._id = -1;
522    }
523
524    void firstInc(Edge &arc, bool& d, const Node& v) const {
525      int de = nodes[v._id].first_out;
526      if (de != -1) {
527        arc._id = de / 2;
528        d = ((de & 1) == 1);
529      } else {
530        arc._id = -1;
531        d = true;
532      }
533    }
534    void nextInc(Edge &arc, bool& d) const {
535      int de = (arcs[(arc._id * 2) | (d ? 1 : 0)].next_out);
536      if (de != -1) {
537        arc._id = de / 2;
538        d = ((de & 1) == 1);
539      } else {
540        arc._id = -1;
541        d = true;     
542      }
543    }
544   
545    static int id(Node v) { return v._id; }
546    static int id(Arc e) { return e._id; }
547    static int id(Edge e) { return e._id; }
548
549    static Node nodeFromId(int id) { return Node(id);}
550    static Arc arcFromId(int id) { return Arc(id);}
551    static Edge edgeFromId(int id) { return Edge(id);}
552
553    Node addNode() {     
554      int n = nodes.size();
555      nodes.push_back(NodeT());
556      nodes[n].first_out = -1;
557     
558      return Node(n);
559    }
560   
561    Edge addArc(Node u, Node v) {
562      int n = arcs.size();
563      arcs.push_back(ArcT());
564      arcs.push_back(ArcT());
565     
566      arcs[n].target = u._id;
567      arcs[n | 1].target = v._id;
568
569      arcs[n].next_out = nodes[v._id].first_out;
570      nodes[v._id].first_out = n;
571
572      arcs[n | 1].next_out = nodes[u._id].first_out;   
573      nodes[u._id].first_out = (n | 1);
574
575      return Edge(n / 2);
576    }
577   
578    void clear() {
579      arcs.clear();
580      nodes.clear();
581    }
582
583  };
584
585  typedef GraphExtender<SmartGraphBase> ExtendedSmartGraphBase;
586
587  /// \ingroup graphs
588  ///
589  /// \brief A smart undirected graph class.
590  ///
591  /// This is a simple and fast graph implementation.
592  /// It is also quite memory efficient, but at the price
593  /// that <b> it does support only limited (only stack-like)
594  /// node and arc deletions</b>.
595  /// Except from this it conforms to
596  /// the \ref concepts::Graph "Graph concept".
597  ///
598  /// It also has an
599  /// important extra feature that
600  /// its maps are real \ref concepts::ReferenceMap "reference map"s.
601  ///
602  /// \sa concepts::Graph.
603  ///
604  class SmartGraph : public ExtendedSmartGraphBase {
605  private:
606
607    ///SmartGraph is \e not copy constructible. Use GraphCopy() instead.
608
609    ///SmartGraph is \e not copy constructible. Use GraphCopy() instead.
610    ///
611    SmartGraph(const SmartGraph &) : ExtendedSmartGraphBase() {};
612
613    ///\brief Assignment of SmartGraph to another one is \e not allowed.
614    ///Use GraphCopy() instead.
615
616    ///Assignment of SmartGraph to another one is \e not allowed.
617    ///Use GraphCopy() instead.
618    void operator=(const SmartGraph &) {}
619
620  public:
621
622    typedef ExtendedSmartGraphBase Parent;
623
624    /// Constructor
625   
626    /// Constructor.
627    ///
628    SmartGraph() {}
629
630    ///Add a new node to the graph.
631   
632    /// \return the new node.
633    ///
634    Node addNode() { return Parent::addNode(); }
635   
636    ///Add a new edge to the graph.
637   
638    ///Add a new edge to the graph with node \c s
639    ///and \c t.
640    ///\return the new edge.
641    Edge addEdge(const Node& s, const Node& t) {
642      return Parent::addArc(s, t);
643    }
644
645    ///Clear the graph.
646   
647    ///Erase all the nodes and edges from the graph.
648    ///
649    void clear() {
650      Parent::clear();
651    }
652
653  public:
654   
655    class Snapshot;
656
657  protected:
658
659    void saveSnapshot(Snapshot &s)
660    {
661      s._graph = this;
662      s.node_num = nodes.size();
663      s.arc_num = arcs.size();
664    }
665
666    void restoreSnapshot(const Snapshot &s)
667    {
668      while(s.arc_num<arcs.size()) {
669        int n=arcs.size()-1;
670        Edge arc=edgeFromId(n/2);
671        Parent::notifier(Edge()).erase(arc);
672        std::vector<Arc> dir;
673        dir.push_back(arcFromId(n));
674        dir.push_back(arcFromId(n-1));
675        Parent::notifier(Arc()).erase(dir);
676        nodes[arcs[n].target].first_out=arcs[n].next_out;
677        nodes[arcs[n-1].target].first_out=arcs[n-1].next_out;
678        arcs.pop_back();
679        arcs.pop_back();
680      }
681      while(s.node_num<nodes.size()) {
682        int n=nodes.size()-1;
683        Node node = nodeFromId(n);
684        Parent::notifier(Node()).erase(node);
685        nodes.pop_back();
686      }
687    }   
688
689  public:
690
691    ///Class to make a snapshot of the digraph and to restrore to it later.
692
693    ///Class to make a snapshot of the digraph and to restrore to it later.
694    ///
695    ///The newly added nodes and arcs can be removed using the
696    ///restore() function.
697    ///
698    ///\note After you restore a state, you cannot restore
699    ///a later state, in other word you cannot add again the arcs deleted
700    ///by restore() using another one Snapshot instance.
701    ///
702    ///\warning If you do not use correctly the snapshot that can cause
703    ///either broken program, invalid state of the digraph, valid but
704    ///not the restored digraph or no change. Because the runtime performance
705    ///the validity of the snapshot is not stored.
706    class Snapshot
707    {
708      SmartGraph *_graph;
709    protected:
710      friend class SmartGraph;
711      unsigned int node_num;
712      unsigned int arc_num;
713    public:
714      ///Default constructor.
715     
716      ///Default constructor.
717      ///To actually make a snapshot you must call save().
718      ///
719      Snapshot() : _graph(0) {}
720      ///Constructor that immediately makes a snapshot
721     
722      ///This constructor immediately makes a snapshot of the digraph.
723      ///\param g The digraph we make a snapshot of.
724      Snapshot(SmartGraph &graph) {
725        graph.saveSnapshot(*this);
726      }
727
728      ///Make a snapshot.
729
730      ///Make a snapshot of the graph.
731      ///
732      ///This function can be called more than once. In case of a repeated
733      ///call, the previous snapshot gets lost.
734      ///\param g The digraph we make the snapshot of.
735      void save(SmartGraph &graph)
736      {
737        graph.saveSnapshot(*this);
738      }
739
740      ///Undo the changes until a snapshot.
741     
742      ///Undo the changes until a snapshot created by save().
743      ///
744      ///\note After you restored a state, you cannot restore
745      ///a later state, in other word you cannot add again the arcs deleted
746      ///by restore().
747      void restore()
748      {
749        _graph->restoreSnapshot(*this);
750      }
751    };
752  };
753 
754} //namespace lemon
755
756
757#endif //LEMON_SMART_GRAPH_H
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