COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/list_graph.h @ 1790:c7dd9d8c770a

Last change on this file since 1790:c7dd9d8c770a was 1774:9fd56d75293e, checked in by Balazs Dezso, 14 years ago

UnsupportedException? on erase with Snapshot

File size: 16.2 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 <lemon/error.h>
34
35#include <list>
36
37namespace lemon {
38
39  class ListGraphBase {
40
41  protected:
42    struct NodeT {
43      int first_in, first_out;
44      int prev, next;
45    };
46 
47    struct EdgeT {
48      int target, source;
49      int prev_in, prev_out;
50      int next_in, next_out;
51    };
52
53    std::vector<NodeT> nodes;
54
55    int first_node;
56
57    int first_free_node;
58
59    std::vector<EdgeT> edges;
60
61    int first_free_edge;
62   
63  public:
64   
65    typedef ListGraphBase Graph;
66   
67    class Node {
68      friend class ListGraphBase;
69    protected:
70
71      int id;
72      Node(int pid) { id = pid;}
73
74    public:
75      Node() {}
76      Node (Invalid) { id = -1; }
77      bool operator==(const Node& node) const {return id == node.id;}
78      bool operator!=(const Node& node) const {return id != node.id;}
79      bool operator<(const Node& node) const {return id < node.id;}
80    };
81
82    class Edge {
83      friend class ListGraphBase;
84    protected:
85
86      int id;
87      Edge(int pid) { id = pid;}
88
89    public:
90      Edge() {}
91      Edge (Invalid) { id = -1; }
92      bool operator==(const Edge& edge) const {return id == edge.id;}
93      bool operator!=(const Edge& edge) const {return id != edge.id;}
94      bool operator<(const Edge& edge) const {return id < edge.id;}
95    };
96
97
98
99    ListGraphBase()
100      : nodes(), first_node(-1),
101        first_free_node(-1), edges(), first_free_edge(-1) {}
102
103   
104    /// Maximum node ID.
105   
106    /// Maximum node ID.
107    ///\sa id(Node)
108    int maxId(Node = INVALID) const { return nodes.size()-1; }
109
110    /// Maximum edge ID.
111   
112    /// Maximum edge ID.
113    ///\sa id(Edge)
114    int maxId(Edge = INVALID) const { return edges.size()-1; }
115
116    Node source(Edge e) const { return edges[e.id].source; }
117    Node target(Edge e) const { return edges[e.id].target; }
118
119
120    void first(Node& node) const {
121      node.id = first_node;
122    }
123
124    void next(Node& node) const {
125      node.id = nodes[node.id].next;
126    }
127
128
129    void first(Edge& e) const {
130      int n;
131      for(n = first_node;
132          n!=-1 && nodes[n].first_in == -1;
133          n = nodes[n].next);
134      e.id = (n == -1) ? -1 : nodes[n].first_in;
135    }
136
137    void next(Edge& edge) const {
138      if (edges[edge.id].next_in != -1) {
139        edge.id = edges[edge.id].next_in;
140      } else {
141        int n;
142        for(n = nodes[edges[edge.id].target].next;
143          n!=-1 && nodes[n].first_in == -1;
144          n = nodes[n].next);
145        edge.id = (n == -1) ? -1 : nodes[n].first_in;
146      }     
147    }
148
149    void firstOut(Edge &e, const Node& v) const {
150      e.id = nodes[v.id].first_out;
151    }
152    void nextOut(Edge &e) const {
153      e.id=edges[e.id].next_out;
154    }
155
156    void firstIn(Edge &e, const Node& v) const {
157      e.id = nodes[v.id].first_in;
158    }
159    void nextIn(Edge &e) const {
160      e.id=edges[e.id].next_in;
161    }
162
163   
164    static int id(Node v) { return v.id; }
165    static int id(Edge e) { return e.id; }
166
167    static Node fromId(int id, Node) { return Node(id);}
168    static Edge fromId(int id, Edge) { return Edge(id);}
169
170    /// Adds a new node to the graph.
171
172    /// \warning It adds the new node to the front of the list.
173    /// (i.e. the lastly added node becomes the first.)
174    Node addNode() {     
175      int n;
176     
177      if(first_free_node==-1) {
178        n = nodes.size();
179        nodes.push_back(NodeT());
180      } else {
181        n = first_free_node;
182        first_free_node = nodes[n].next;
183      }
184     
185      nodes[n].next = first_node;
186      if(first_node != -1) nodes[first_node].prev = n;
187      first_node = n;
188      nodes[n].prev = -1;
189     
190      nodes[n].first_in = nodes[n].first_out = -1;
191     
192      return Node(n);
193    }
194   
195    Edge addEdge(Node u, Node v) {
196      int n;     
197
198      if (first_free_edge == -1) {
199        n = edges.size();
200        edges.push_back(EdgeT());
201      } else {
202        n = first_free_edge;
203        first_free_edge = edges[n].next_in;
204      }
205     
206      edges[n].source = u.id;
207      edges[n].target = v.id;
208
209      edges[n].next_out = nodes[u.id].first_out;
210      if(nodes[u.id].first_out != -1) {
211        edges[nodes[u.id].first_out].prev_out = n;
212      }
213     
214      edges[n].next_in = nodes[v.id].first_in;
215      if(nodes[v.id].first_in != -1) {
216        edges[nodes[v.id].first_in].prev_in = n;
217      }
218     
219      edges[n].prev_in = edges[n].prev_out = -1;
220       
221      nodes[u.id].first_out = nodes[v.id].first_in = n;
222
223      return Edge(n);
224    }
225   
226    void erase(const Node& node) {
227      int n = node.id;
228     
229      if(nodes[n].next != -1) {
230        nodes[nodes[n].next].prev = nodes[n].prev;
231      }
232     
233      if(nodes[n].prev != -1) {
234        nodes[nodes[n].prev].next = nodes[n].next;
235      } else {
236        first_node = nodes[n].next;
237      }
238     
239      nodes[n].next = first_free_node;
240      first_free_node = n;
241
242    }
243   
244    void erase(const Edge& edge) {
245      int n = edge.id;
246     
247      if(edges[n].next_in!=-1) {
248        edges[edges[n].next_in].prev_in = edges[n].prev_in;
249      }
250
251      if(edges[n].prev_in!=-1) {
252        edges[edges[n].prev_in].next_in = edges[n].next_in;
253      } else {
254        nodes[edges[n].target].first_in = edges[n].next_in;
255      }
256
257     
258      if(edges[n].next_out!=-1) {
259        edges[edges[n].next_out].prev_out = edges[n].prev_out;
260      }
261
262      if(edges[n].prev_out!=-1) {
263        edges[edges[n].prev_out].next_out = edges[n].next_out;
264      } else {
265        nodes[edges[n].source].first_out = edges[n].next_out;
266      }
267     
268      edges[n].next_in = first_free_edge;
269      first_free_edge = n;     
270
271    }
272
273    void clear() {
274      edges.clear();
275      nodes.clear();
276      first_node = first_free_node = first_free_edge = -1;
277    }
278
279  protected:
280    void _changeTarget(Edge e, Node n)
281    {
282      if(edges[e.id].next_in != -1)
283        edges[edges[e.id].next_in].prev_in = edges[e.id].prev_in;
284      if(edges[e.id].prev_in != -1)
285        edges[edges[e.id].prev_in].next_in = edges[e.id].next_in;
286      else nodes[edges[e.id].target].first_in = edges[e.id].next_in;
287      if (nodes[n.id].first_in != -1) {
288        edges[nodes[n.id].first_in].prev_in = e.id;
289      }
290      edges[e.id].target = n.id;
291      edges[e.id].prev_in = -1;
292      edges[e.id].next_in = nodes[n.id].first_in;
293      nodes[n.id].first_in = e.id;
294    }
295    void _changeSource(Edge e, Node n)
296    {
297      if(edges[e.id].next_out != -1)
298        edges[edges[e.id].next_out].prev_out = edges[e.id].prev_out;
299      if(edges[e.id].prev_out != -1)
300        edges[edges[e.id].prev_out].next_out = edges[e.id].next_out;
301      else nodes[edges[e.id].source].first_out = edges[e.id].next_out;
302      if (nodes[n.id].first_out != -1) {
303        edges[nodes[n.id].first_out].prev_out = e.id;
304      }
305      edges[e.id].source = n.id;
306      edges[e.id].prev_out = -1;
307      edges[e.id].next_out = nodes[n.id].first_out;
308      nodes[n.id].first_out = e.id;
309    }
310
311  };
312
313  typedef ErasableGraphExtender<
314    ClearableGraphExtender<
315    ExtendableGraphExtender<
316    MappableGraphExtender<
317    IterableGraphExtender<
318    AlterableGraphExtender<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    ///Class to make a snapshot of the graph and to restrore to it later.
434
435    ///Class to make a snapshot of the graph and to restrore to it later.
436    ///
437    ///The newly added nodes and edges can be removed using the
438    ///restore() function.
439    ///
440    ///\warning Edge and node deletions cannot be restored.
441    ///\warning Snapshots cannot be nested.
442    class Snapshot : protected AlterationNotifier<Node>::ObserverBase,
443                     protected AlterationNotifier<Edge>::ObserverBase
444    {
445    public:
446     
447      class UnsupportedOperation : public LogicError {
448      public:
449        virtual const char* exceptionName() const {
450          return "lemon::ListGraph::Snapshot::UnsupportedOperation";
451        }
452      };
453           
454
455      protected:
456     
457      ListGraph *g;
458      std::list<Node> added_nodes;
459      std::list<Edge> added_edges;
460     
461      bool active;
462      virtual void add(const Node& n) {
463        added_nodes.push_back(n);
464      };
465      virtual void erase(const Node&)
466      {
467        throw UnsupportedOperation();
468      }
469      virtual void add(const Edge& n) {
470        added_edges.push_back(n);
471      };
472      virtual void erase(const Edge&)
473      {
474        throw UnsupportedOperation();
475      }
476
477      ///\bug What is this used for?
478      ///
479      virtual void build() {}
480      ///\bug What is this used for?
481      ///
482      virtual void clear() {}
483
484      void regist(ListGraph &_g) {
485        g=&_g;
486        AlterationNotifier<Node>::ObserverBase::
487          attach(g->getNotifier(Node()));
488        AlterationNotifier<Edge>::ObserverBase::
489          attach(g->getNotifier(Edge()));
490      }
491           
492      void deregist() {
493        AlterationNotifier<Node>::ObserverBase::
494          detach();
495        AlterationNotifier<Edge>::ObserverBase::
496          detach();
497        g=0;
498      }
499
500    public:
501      ///Default constructur.
502     
503      ///Default constructur.
504      ///To actually make a snapshot you must call save().
505      ///
506      Snapshot() : g(0) {}
507      ///Constructor that immediately makes a snapshot.
508     
509      ///This constructor immediately makes a snapshot of the graph.
510      ///\param _g The graph we make a snapshot of.
511      Snapshot(ListGraph &_g) {
512        regist(_g);
513      }
514      ///\bug Is it necessary?
515      ///
516      ~Snapshot()
517      {
518        if(g) deregist();
519      }
520     
521      ///Make a snapshot.
522
523      ///Make a snapshot of the graph.
524      ///
525      ///This function can be called more than once. In case of a repeated
526      ///call, the previous snapshot gets lost.
527      ///\param _g The graph we make the snapshot of.
528      void save(ListGraph &_g)
529      {
530        if(g!=&_g) {
531          if(g) deregist();
532          regist(_g);
533        }
534        added_nodes.clear();
535        added_edges.clear();
536      }
537     
538    ///Undo the changes until the last snapshot.
539
540    ///Undo the changes until last snapshot created by save().
541    ///
542    ///\todo This function might be called undo().
543      void restore() {
544        ListGraph &old_g=*g;
545        deregist();
546        while(!added_edges.empty()) {
547          old_g.erase(added_edges.front());
548          added_edges.pop_front();
549        }
550        while(!added_nodes.empty()) {
551          old_g.erase(added_nodes.front());
552          added_nodes.pop_front();
553        }
554      }
555    };
556   
557  };
558
559  ///@}
560
561  /**************** Undirected List Graph ****************/
562
563  typedef ErasableUndirGraphExtender<
564    ClearableUndirGraphExtender<
565    ExtendableUndirGraphExtender<
566    MappableUndirGraphExtender<
567    IterableUndirGraphExtender<
568    AlterableUndirGraphExtender<
569    UndirGraphExtender<ListGraphBase> > > > > > > ExtendedUndirListGraphBase;
570
571  /// \addtogroup graphs
572  /// @{
573
574  ///An undirected list graph class.
575
576  ///This is a simple and fast erasable undirected graph implementation.
577  ///
578  ///It conforms to the
579  ///\ref concept::UndirGraph "UndirGraph" concept.
580  ///
581  ///\sa concept::UndirGraph.
582  ///
583  ///\todo Snapshot, reverseEdge(), changeTarget(), changeSource(), contract()
584  ///haven't been implemented yet.
585  ///
586  class UndirListGraph : public ExtendedUndirListGraphBase {
587  public:
588    typedef ExtendedUndirListGraphBase Parent;
589    /// \brief Changes the target of \c e to \c n
590    ///
591    /// Changes the target of \c e to \c n
592    ///
593    /// \note The <tt>Edge</tt>'s and <tt>OutEdge</tt>'s
594    /// referencing the changed edge remain
595    /// valid. However <tt>InEdge</tt>'s are invalidated.
596    void changeTarget(UndirEdge e, Node n) {
597      _changeTarget(e,n);
598    }
599    /// Changes the source of \c e to \c n
600    ///
601    /// Changes the source of \c e to \c n
602    ///
603    ///\note The <tt>Edge</tt>'s and <tt>InEdge</tt>'s
604    ///referencing the changed edge remain
605    ///valid. However <tt>OutEdge</tt>'s are invalidated.
606    void changeSource(UndirEdge e, Node n) {
607      _changeSource(e,n);
608    }
609    /// \brief Contract two nodes.
610    ///
611    /// This function contracts two nodes.
612    ///
613    /// Node \p b will be removed but instead of deleting
614    /// its neighboring edges, they will be joined to \p a.
615    /// The last parameter \p r controls whether to remove loops. \c true
616    /// means that loops will be removed.
617    ///
618    /// \note The <tt>Edge</tt>s
619    /// referencing a moved edge remain
620    /// valid.
621    void contract(Node a, Node b, bool r = true) {
622      for(IncEdgeIt e(*this, b); e!=INVALID;) {
623        IncEdgeIt f = e; ++f;
624        if (r && runningNode(e) == a) {
625          erase(e);
626        } else if (source(e) == b) {
627          changeSource(e, a);
628        } else {
629          changeTarget(e, a);
630        }
631        e = f;
632      }
633      erase(b);
634    }
635  };
636
637 
638  /// @} 
639} //namespace lemon
640 
641
642#endif
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