COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/list_graph.h @ 1773:ea5927cef15c

Last change on this file since 1773:ea5927cef15c was 1770:657de7e5043c, checked in by Alpar Juttner, 14 years ago

SnapShot? -> Snapshot

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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 ErasableGraphExtender<
312    ClearableGraphExtender<
313    ExtendableGraphExtender<
314    MappableGraphExtender<
315    IterableGraphExtender<
316    AlterableGraphExtender<ListGraphBase> > > > > > ExtendedListGraphBase;
317
318  /// \addtogroup graphs
319  /// @{
320
321  ///A list graph class.
322
323  ///This is a simple and fast erasable graph implementation.
324  ///
325  ///It addition that it conforms to the
326  ///\ref concept::ErasableGraph "ErasableGraph" concept,
327  ///it also provides several additional useful extra functionalities.
328  ///\sa concept::ErasableGraph.
329
330  class ListGraph : public ExtendedListGraphBase
331  {
332  public:
333    /// Changes the target of \c e to \c n
334
335    /// Changes the target of \c e to \c n
336    ///
337    ///\note The <tt>Edge</tt>'s and <tt>OutEdge</tt>'s
338    ///referencing the changed edge remain
339    ///valid. However <tt>InEdge</tt>'s are invalidated.
340    void changeTarget(Edge e, Node n) {
341      _changeTarget(e,n);
342    }
343    /// Changes the source of \c e to \c n
344
345    /// Changes the source of \c e to \c n
346    ///
347    ///\note The <tt>Edge</tt>'s and <tt>InEdge</tt>'s
348    ///referencing the changed edge remain
349    ///valid. However <tt>OutEdge</tt>'s are invalidated.
350    void changeSource(Edge e, Node n) {
351      _changeSource(e,n);
352    }
353
354    /// Invert the direction of an edge.
355
356    ///\note The <tt>Edge</tt>'s
357    ///referencing the changed edge remain
358    ///valid. However <tt>OutEdge</tt>'s  and <tt>InEdge</tt>'s are invalidated.
359    void reverseEdge(Edge e) {
360      Node t=target(e);
361      _changeTarget(e,source(e));
362      _changeSource(e,t);
363    }
364
365    ///Using this it possible to avoid the superfluous memory allocation.
366
367    ///Using this it possible to avoid the superfluous memory allocation.
368    ///\todo more docs...
369    void reserveEdge(int n) { edges.reserve(n); };
370
371    ///Contract two nodes.
372
373    ///This function contracts two nodes.
374    ///
375    ///Node \p b will be removed but instead of deleting
376    ///its neighboring edges, they will be joined to \p a.
377    ///The last parameter \p r controls whether to remove loops. \c true
378    ///means that loops will be removed.
379    ///
380    ///\note The <tt>Edge</tt>s
381    ///referencing a moved edge remain
382    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
383    ///may be invalidated.
384    void contract(Node a, Node b, bool r = true)
385    {
386      for(OutEdgeIt e(*this,b);e!=INVALID;) {
387        OutEdgeIt f=e;
388        ++f;
389        if(r && target(e)==a) erase(e);
390        else changeSource(e,a);
391        e=f;
392      }
393      for(InEdgeIt e(*this,b);e!=INVALID;) {
394        InEdgeIt f=e;
395        ++f;
396        if(r && source(e)==a) erase(e);
397        else changeTarget(e,a);
398        e=f;
399      }
400      erase(b);
401    }
402
403    ///Split a node.
404
405    ///This function splits a node. First a new node is added to the graph,
406    ///then the source of each outgoing edge of \c n is moved to this new node.
407    ///If \c connect is \c true (this is the default value), then a new edge
408    ///from \c n to the newly created node is also added.
409    ///\return The newly created node.
410    ///
411    ///\note The <tt>Edge</tt>s
412    ///referencing a moved edge remain
413    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
414    ///may be invalidated.
415    ///\warning This functionality cannot be used together with the Snapshot
416    ///feature.
417    ///\todo It could be implemented in a bit faster way.
418    Node split(Node n, bool connect = true)
419    {
420      Node b = addNode();
421      for(OutEdgeIt e(*this,n);e!=INVALID;) {
422        OutEdgeIt f=e;
423        ++f;
424        changeSource(e,b);
425        e=f;
426      }
427      if(connect) addEdge(n,b);
428      return b;
429    }
430     
431    ///Class to make a snapshot of the graph and to restrore to it later.
432
433    ///Class to make a snapshot of the graph and to restrore to it later.
434    ///
435    ///The newly added nodes and edges can be removed using the
436    ///restore() function.
437    ///
438    ///\warning Edge and node deletions cannot be restored.
439    ///\warning Snapshots cannot be nested.
440    class Snapshot : protected AlterationNotifier<Node>::ObserverBase,
441                     protected AlterationNotifier<Edge>::ObserverBase
442    {
443      protected:
444     
445      ListGraph *g;
446      std::list<Node> added_nodes;
447      std::list<Edge> added_edges;
448     
449      bool active;
450      virtual void add(const Node& n) {
451        added_nodes.push_back(n);
452      };
453      ///\bug Exception...
454      ///
455      virtual void erase(const Node&)
456      {
457        exit(1);
458      }
459      virtual void add(const Edge& n) {
460        added_edges.push_back(n);
461      };
462      ///\bug Exception...
463      ///
464      virtual void erase(const Edge&)
465      {
466        exit(1);
467      }
468
469      ///\bug What is this used for?
470      ///
471      virtual void build() {}
472      ///\bug What is this used for?
473      ///
474      virtual void clear() {}
475
476      void regist(ListGraph &_g) {
477        g=&_g;
478        AlterationNotifier<Node>::ObserverBase::
479          attach(g->getNotifier(Node()));
480        AlterationNotifier<Edge>::ObserverBase::
481          attach(g->getNotifier(Edge()));
482      }
483           
484      void deregist() {
485        AlterationNotifier<Node>::ObserverBase::
486          detach();
487        AlterationNotifier<Edge>::ObserverBase::
488          detach();
489        g=0;
490      }
491           
492    public:
493      ///Default constructur.
494     
495      ///Default constructur.
496      ///To actually make a snapshot you must call save().
497      ///
498      Snapshot() : g(0) {}
499      ///Constructor that immediately makes a snapshot.
500     
501      ///This constructor immediately makes a snapshot of the graph.
502      ///\param _g The graph we make a snapshot of.
503      Snapshot(ListGraph &_g) {
504        regist(_g);
505      }
506      ///\bug Is it necessary?
507      ///
508      ~Snapshot()
509      {
510        if(g) deregist();
511      }
512     
513      ///Make a snapshot.
514
515      ///Make a snapshot of the graph.
516      ///
517      ///This function can be called more than once. In case of a repeated
518      ///call, the previous snapshot gets lost.
519      ///\param _g The graph we make the snapshot of.
520      void save(ListGraph &_g)
521      {
522        if(g!=&_g) {
523          if(g) deregist();
524          regist(_g);
525        }
526        added_nodes.clear();
527        added_edges.clear();
528      }
529     
530    ///Undo the changes until the last snapshot.
531
532    ///Undo the changes until last snapshot created by save().
533    ///
534    ///\todo This function might be called undo().
535      void restore() {
536        ListGraph &old_g=*g;
537        deregist();
538        while(!added_edges.empty()) {
539          old_g.erase(added_edges.front());
540          added_edges.pop_front();
541        }
542        while(!added_nodes.empty()) {
543          old_g.erase(added_nodes.front());
544          added_nodes.pop_front();
545        }
546      }
547    };
548   
549  };
550
551  ///@}
552
553  /**************** Undirected List Graph ****************/
554
555  typedef ErasableUndirGraphExtender<
556    ClearableUndirGraphExtender<
557    ExtendableUndirGraphExtender<
558    MappableUndirGraphExtender<
559    IterableUndirGraphExtender<
560    AlterableUndirGraphExtender<
561    UndirGraphExtender<ListGraphBase> > > > > > > ExtendedUndirListGraphBase;
562
563  /// \addtogroup graphs
564  /// @{
565
566  ///An undirected list graph class.
567
568  ///This is a simple and fast erasable undirected graph implementation.
569  ///
570  ///It conforms to the
571  ///\ref concept::UndirGraph "UndirGraph" concept.
572  ///
573  ///\sa concept::UndirGraph.
574  ///
575  ///\todo Snapshot, reverseEdge(), changeTarget(), changeSource(), contract()
576  ///haven't been implemented yet.
577  ///
578  class UndirListGraph : public ExtendedUndirListGraphBase {
579  public:
580    typedef ExtendedUndirListGraphBase Parent;
581    /// \brief Changes the target of \c e to \c n
582    ///
583    /// Changes the target of \c e to \c n
584    ///
585    /// \note The <tt>Edge</tt>'s and <tt>OutEdge</tt>'s
586    /// referencing the changed edge remain
587    /// valid. However <tt>InEdge</tt>'s are invalidated.
588    void changeTarget(UndirEdge e, Node n) {
589      _changeTarget(e,n);
590    }
591    /// Changes the source of \c e to \c n
592    ///
593    /// Changes the source of \c e to \c n
594    ///
595    ///\note The <tt>Edge</tt>'s and <tt>InEdge</tt>'s
596    ///referencing the changed edge remain
597    ///valid. However <tt>OutEdge</tt>'s are invalidated.
598    void changeSource(UndirEdge e, Node n) {
599      _changeSource(e,n);
600    }
601    /// \brief Contract two nodes.
602    ///
603    /// This function contracts two nodes.
604    ///
605    /// Node \p b will be removed but instead of deleting
606    /// its neighboring edges, they will be joined to \p a.
607    /// The last parameter \p r controls whether to remove loops. \c true
608    /// means that loops will be removed.
609    ///
610    /// \note The <tt>Edge</tt>s
611    /// referencing a moved edge remain
612    /// valid.
613    void contract(Node a, Node b, bool r = true) {
614      for(IncEdgeIt e(*this, b); e!=INVALID;) {
615        IncEdgeIt f = e; ++f;
616        if (r && runningNode(e) == a) {
617          erase(e);
618        } else if (source(e) == b) {
619          changeSource(e, a);
620        } else {
621          changeTarget(e, a);
622        }
623        e = f;
624      }
625      erase(b);
626    }
627  };
628
629 
630  /// @} 
631} //namespace lemon
632 
633
634#endif
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