COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/list_graph.h @ 1164:80bb73097736

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1/* -*- C++ -*-
2 * src/lemon/list_graph.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, 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, SymListGraph, NodeSet and EdgeSet classes.
23
24#include <lemon/erasable_graph_extender.h>
25#include <lemon/clearable_graph_extender.h>
26#include <lemon/extendable_graph_extender.h>
27#include <lemon/iterable_graph_extender.h>
28#include <lemon/alteration_notifier.h>
29#include <lemon/default_map.h>
30
31#include <lemon/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 _moveTarget(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      edges[e.id].target = n.id;
286      edges[e.id].prev_in = -1;
287      edges[e.id].next_in = nodes[n.id].first_in;
288      nodes[n.id].first_in = e.id;
289    }
290    void _moveSource(Edge e, Node n)
291    {
292      if(edges[e.id].next_out != -1)
293        edges[edges[e.id].next_out].prev_out = edges[e.id].prev_out;
294      if(edges[e.id].prev_out != -1)
295        edges[edges[e.id].prev_out].next_out = edges[e.id].next_out;
296      else nodes[edges[e.id].source].first_out = edges[e.id].next_out;
297      edges[e.id].source = n.id;
298      edges[e.id].prev_out = -1;
299      edges[e.id].next_out = nodes[n.id].first_out;
300      nodes[n.id].first_out = e.id;
301    }
302
303  };
304
305  typedef AlterableGraphExtender<ListGraphBase> AlterableListGraphBase;
306  typedef IterableGraphExtender<AlterableListGraphBase> IterableListGraphBase;
307  typedef DefaultMappableGraphExtender<IterableListGraphBase> MappableListGraphBase;
308  typedef ExtendableGraphExtender<MappableListGraphBase> ExtendableListGraphBase;
309  typedef ClearableGraphExtender<ExtendableListGraphBase> ClearableListGraphBase;
310  typedef ErasableGraphExtender<ClearableListGraphBase> ErasableListGraphBase;
311
312/// \addtogroup graphs
313/// @{
314
315  ///A list graph class.
316
317  ///This is a simple and fast erasable graph implementation.
318  ///
319  ///It addition that it conforms to the
320  ///\ref concept::ErasableGraph "ErasableGraph" concept,
321  ///it also provides several additional useful extra functionalities.
322  ///\sa concept::ErasableGraph.
323
324  class ListGraph : public ErasableListGraphBase
325  {
326  public:
327    /// Moves the target of \c e to \c n
328
329    /// Moves the target of \c e to \c n
330    ///
331    ///\note The <tt>Edge</tt>'s and <tt>OutEdge</tt>'s
332    ///referencing the moved edge remain
333    ///valid. However <tt>InEdge</tt>'s are invalidated.
334    void moveTarget(Edge e, Node n) { _moveTarget(e,n); }
335    /// Moves the source of \c e to \c n
336
337    /// Moves the source of \c e to \c n
338    ///
339    ///\note The <tt>Edge</tt>'s and <tt>InEdge</tt>'s
340    ///referencing the moved edge remain
341    ///valid. However <tt>OutEdge</tt>'s are invalidated.
342    void moveSource(Edge e, Node n) { _moveSource(e,n); }
343
344    /// Invert the direction of an edge.
345
346    ///\note The <tt>Edge</tt>'s
347    ///referencing the moved edge remain
348    ///valid. However <tt>OutEdge</tt>'s  and <tt>InEdge</tt>'s are invalidated.
349    void reverseEdge(Edge e) {
350      Node t=target(e);
351      _moveTarget(e,source(e));
352      _moveSource(e,t);
353    }
354
355    ///Using this it possible to avoid the superfluous memory allocation.
356
357    ///Using this it possible to avoid the superfluous memory allocation.
358    ///\todo more docs...
359    void reserveEdge(int n) { edges.reserve(n); };
360
361    ///Contract two nodes.
362
363    ///This function contracts two nodes.
364    ///
365    ///Node \p b will be removed but instead of deleting
366    ///its neighboring edges, they will be joined to \p a.
367    ///The last parameter \p r controls whether to remove loops. \c true
368    ///means that loops will be removed.
369    ///
370    ///\note The <tt>Edge</tt>s
371    ///referencing the moved edge remain
372    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
373    ///may be invalidated.
374    void contract(Node a,Node b,bool r=true)
375    {
376      for(OutEdgeIt e(*this,b);e!=INVALID;) {
377        OutEdgeIt f=e;
378        ++f;
379        if(r && target(e)==a) erase(e);
380        else moveSource(e,b);
381        e=f;
382      }
383      for(InEdgeIt e(*this,b);e!=INVALID;) {
384        InEdgeIt f=e;
385        ++f;
386        if(r && source(e)==a) erase(e);
387        else moveTarget(e,b);
388        e=f;
389      }
390      erase(b);
391    }
392
393
394    ///Class to make a snapshot of the graph and to restrore to it later.
395
396    ///Class to make a snapshot of the graph and to restrore to it later.
397    ///
398    ///The newly added nodes and edges can be removed using the
399    ///restore() function.
400    ///
401    ///\warning Edge and node deletions cannot be restored.
402    ///\warning SnapShots cannot be nested.
403    ///\todo \c SnapShot or \c Snapshot?
404    class SnapShot : protected AlterationNotifier<Node>::ObserverBase,
405                     protected AlterationNotifier<Edge>::ObserverBase
406    {
407      protected:
408     
409      ListGraph *g;
410      std::list<Node> added_nodes;
411      std::list<Edge> added_edges;
412     
413      bool active;
414      virtual void add(const Node& n) {
415        added_nodes.push_back(n);
416      };
417      ///\bug Exception...
418      ///
419      virtual void erase(const Node&)
420      {
421        exit(1);
422      }
423      virtual void add(const Edge& n) {
424        added_edges.push_back(n);
425      };
426      ///\bug Exception...
427      ///
428      virtual void erase(const Edge&)
429      {
430        exit(1);
431      }
432
433      void regist(ListGraph &_g) {
434        g=&_g;
435        AlterationNotifier<Node>::ObserverBase::
436          attach(g->getNotifier(Node()));
437        AlterationNotifier<Edge>::ObserverBase::
438          attach(g->getNotifier(Edge()));
439      }
440           
441      void deregist() {
442        AlterationNotifier<Node>::ObserverBase::
443          detach();
444        AlterationNotifier<Edge>::ObserverBase::
445          detach();
446        g=0;
447      }
448           
449    public:
450      ///Default constructur.
451     
452      ///Default constructur.
453      ///To actually make a snapshot you must call save().
454      ///
455      SnapShot() : g(0) {}
456      ///Constructor that immediately makes a snapshot.
457     
458      ///This constructor immediately makes a snapshot of the graph.
459      ///\param _g The graph we make a snapshot of.
460      SnapShot(ListGraph &_g) {
461        regist(_g);
462      }
463      ///\bug Is it necessary?
464      ///
465      ~SnapShot()
466      {
467        if(g) deregist();
468      }
469     
470      ///Make a snapshot.
471
472      ///Make a snapshot of the graph.
473      ///
474      ///This function can be called more than once. In case of a repeated
475      ///call, the previous snapshot gets lost.
476      ///\param _g The graph we make the snapshot of.
477      void save(ListGraph &_g)
478      {
479        if(g!=&_g) {
480          if(g) deregist();
481          regist(_g);
482        }
483        added_nodes.clear();
484        added_edges.clear();
485      }
486     
487    ///Undo the changes until the last snapshot.
488
489    ///Undo the changes until last snapshot created by save().
490    ///
491    ///\todo This function might be called undo().
492      void restore() {
493        deregist();
494        while(!added_edges.empty()) {
495          g->erase(added_edges.front());
496          added_edges.pop_front();
497        }
498        while(!added_nodes.empty()) {
499          g->erase(added_nodes.front());
500          added_nodes.pop_front();
501        }
502      }
503    };
504   
505  };
506
507
508  /**************** Undirected List Graph ****************/
509
510  typedef ErasableUndirGraphExtender<
511    ClearableUndirGraphExtender<
512    ExtendableUndirGraphExtender<
513    MappableUndirGraphExtender<
514    IterableUndirGraphExtender<
515    AlterableUndirGraphExtender<
516    UndirGraphExtender<ListGraphBase> > > > > > > ErasableUndirListGraphBase;
517
518  ///An undirected list graph class.
519
520  ///This is a simple and fast erasable undirected graph implementation.
521  ///
522  ///It conforms to the
523  ///\ref concept::UndirGraph "UndirGraph" concept.
524  ///
525  ///\sa concept::UndirGraph.
526  ///
527  ///\todo SnapShot, reverseEdge(), moveTarget(), moveSource(), contract()
528  ///haven't been implemented yet.
529  ///
530  class UndirListGraph : public ErasableUndirListGraphBase {
531  };
532
533 
534  /// @} 
535} //namespace lemon
536 
537
538#endif
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