COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/list_graph.h @ 1875:98698b69a902

Last change on this file since 1875:98698b69a902 was 1875:98698b69a902, checked in by Alpar Juttner, 14 years ago

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