COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/graph_utils.h @ 1830:ffd6d50fb155

Last change on this file since 1830:ffd6d50fb155 was 1830:ffd6d50fb155, checked in by Balazs Dezso, 14 years ago

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1/* -*- C++ -*-
2 * lemon/graph_utils.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_GRAPH_UTILS_H
18#define LEMON_GRAPH_UTILS_H
19
20#include <iterator>
21#include <vector>
22#include <map>
23#include <cmath>
24
25#include <lemon/invalid.h>
26#include <lemon/utility.h>
27#include <lemon/maps.h>
28#include <lemon/traits.h>
29#include <lemon/bits/alteration_notifier.h>
30
31///\ingroup gutils
32///\file
33///\brief Graph utilities.
34///
35///
36
37
38namespace lemon {
39
40  /// \addtogroup gutils
41  /// @{
42
43  ///Creates convenience typedefs for the graph types and iterators
44
45  ///This \c \#define creates convenience typedefs for the following types
46  ///of \c Graph: \c Node,  \c NodeIt, \c Edge, \c EdgeIt, \c InEdgeIt,
47  ///\c OutEdgeIt,  \c BoolNodeMap,  \c IntNodeMap,  \c DoubleNodeMap,
48  ///\c BoolEdgeMap, \c IntEdgeMap,  \c DoubleEdgeMap. 
49  ///\note If \c G it a template parameter, it should be used in this way.
50  ///\code
51  ///  GRAPH_TYPEDEFS(typename G)
52  ///\endcode
53  ///
54  ///\warning There are no typedefs for the graph maps because of the lack of
55  ///template typedefs in C++.
56#define GRAPH_TYPEDEFS(Graph)                           \
57  typedef Graph::     Node      Node;                   \
58    typedef Graph::   NodeIt    NodeIt;                 \
59    typedef Graph::   Edge      Edge;                   \
60    typedef Graph::   EdgeIt    EdgeIt;                 \
61    typedef Graph:: InEdgeIt  InEdgeIt;                 \
62    typedef Graph::OutEdgeIt OutEdgeIt;                 
63//     typedef Graph::template NodeMap<bool> BoolNodeMap;             
64//     typedef Graph::template NodeMap<int> IntNodeMap;       
65//     typedef Graph::template NodeMap<double> DoubleNodeMap; 
66//     typedef Graph::template EdgeMap<bool> BoolEdgeMap;             
67//     typedef Graph::template EdgeMap<int> IntEdgeMap;       
68//     typedef Graph::template EdgeMap<double> DoubleEdgeMap;
69 
70  ///Creates convenience typedefs for the undirected graph types and iterators
71
72  ///This \c \#define creates the same convenience typedefs as defined by
73  ///\ref GRAPH_TYPEDEFS(Graph) and three more, namely it creates
74  ///\c UndirEdge, \c UndirEdgeIt, \c IncEdgeIt,
75  ///\c BoolUndirEdgeMap, \c IntUndirEdgeMap,  \c DoubleUndirEdgeMap. 
76  ///
77  ///\note If \c G it a template parameter, it should be used in this way.
78  ///\code
79  ///  UNDIRGRAPH_TYPEDEFS(typename G)
80  ///\endcode
81  ///
82  ///\warning There are no typedefs for the graph maps because of the lack of
83  ///template typedefs in C++.
84#define UNDIRGRAPH_TYPEDEFS(Graph)                              \
85  GRAPH_TYPEDEFS(Graph)                                         \
86    typedef Graph:: UndirEdge   UndirEdge;                      \
87    typedef Graph:: UndirEdgeIt UndirEdgeIt;                    \
88    typedef Graph:: IncEdgeIt   IncEdgeIt;                     
89//     typedef Graph::template UndirEdgeMap<bool> BoolUndirEdgeMap;     
90//     typedef Graph::template UndirEdgeMap<int> IntUndirEdgeMap;
91//     typedef Graph::template UndirEdgeMap<double> DoubleUndirEdgeMap;
92 
93
94
95  /// \brief Function to count the items in the graph.
96  ///
97  /// This function counts the items (nodes, edges etc) in the graph.
98  /// The complexity of the function is O(n) because
99  /// it iterates on all of the items.
100
101  template <typename Graph, typename ItemIt>
102  inline int countItems(const Graph& g) {
103    int num = 0;
104    for (ItemIt it(g); it != INVALID; ++it) {
105      ++num;
106    }
107    return num;
108  }
109
110  // Node counting:
111
112  template <typename Graph>
113  inline typename enable_if<typename Graph::NodeNumTag, int>::type
114  _countNodes(const Graph &g) {
115    return g.nodeNum();
116  }
117
118  template <typename Graph>
119  inline int _countNodes(Wrap<Graph> w) {
120    return countItems<Graph, typename Graph::NodeIt>(w.value);
121  }
122
123  /// \brief Function to count the nodes in the graph.
124  ///
125  /// This function counts the nodes in the graph.
126  /// The complexity of the function is O(n) but for some
127  /// graph structures it is specialized to run in O(1).
128  ///
129  /// \todo refer how to specialize it
130
131  template <typename Graph>
132  inline int countNodes(const Graph& g) {
133    return _countNodes<Graph>(g);
134  }
135
136  // Edge counting:
137
138  template <typename Graph>
139  inline typename enable_if<typename Graph::EdgeNumTag, int>::type
140  _countEdges(const Graph &g) {
141    return g.edgeNum();
142  }
143
144  template <typename Graph>
145  inline int _countEdges(Wrap<Graph> w) {
146    return countItems<Graph, typename Graph::EdgeIt>(w.value);
147  }
148
149  /// \brief Function to count the edges in the graph.
150  ///
151  /// This function counts the edges in the graph.
152  /// The complexity of the function is O(e) but for some
153  /// graph structures it is specialized to run in O(1).
154
155  template <typename Graph>
156  inline int countEdges(const Graph& g) {
157    return _countEdges<Graph>(g);
158  }
159
160  // Undirected edge counting:
161
162  template <typename Graph>
163  inline
164  typename enable_if<typename Graph::EdgeNumTag, int>::type
165  _countUndirEdges(const Graph &g) {
166    return g.undirEdgeNum();
167  }
168
169  template <typename Graph>
170  inline int _countUndirEdges(Wrap<Graph> w) {
171    return countItems<Graph, typename Graph::UndirEdgeIt>(w.value);
172  }
173
174  /// \brief Function to count the undirected edges in the graph.
175  ///
176  /// This function counts the undirected edges in the graph.
177  /// The complexity of the function is O(e) but for some
178  /// graph structures it is specialized to run in O(1).
179
180  template <typename Graph>
181  inline int countUndirEdges(const Graph& g) {
182    return _countUndirEdges<Graph>(g);
183  }
184
185
186
187  template <typename Graph, typename DegIt>
188  inline int countNodeDegree(const Graph& _g, const typename Graph::Node& _n) {
189    int num = 0;
190    for (DegIt it(_g, _n); it != INVALID; ++it) {
191      ++num;
192    }
193    return num;
194  }
195
196  /// \brief Function to count the number of the out-edges from node \c n.
197  ///
198  /// This function counts the number of the out-edges from node \c n
199  /// in the graph. 
200  template <typename Graph>
201  inline int countOutEdges(const Graph& _g,  const typename Graph::Node& _n) {
202    return countNodeDegree<Graph, typename Graph::OutEdgeIt>(_g, _n);
203  }
204
205  /// \brief Function to count the number of the in-edges to node \c n.
206  ///
207  /// This function counts the number of the in-edges to node \c n
208  /// in the graph. 
209  template <typename Graph>
210  inline int countInEdges(const Graph& _g,  const typename Graph::Node& _n) {
211    return countNodeDegree<Graph, typename Graph::InEdgeIt>(_g, _n);
212  }
213
214  /// \brief Function to count the number of the inc-edges to node \c n.
215  ///
216  /// This function counts the number of the inc-edges to node \c n
217  /// in the graph. 
218  template <typename Graph>
219  inline int countIncEdges(const Graph& _g,  const typename Graph::Node& _n) {
220    return countNodeDegree<Graph, typename Graph::IncEdgeIt>(_g, _n);
221  }
222
223
224  template <typename Graph>
225  inline
226  typename enable_if<typename Graph::FindEdgeTag, typename Graph::Edge>::type
227  _findEdge(const Graph &g,
228            typename Graph::Node u, typename Graph::Node v,
229            typename Graph::Edge prev = INVALID) {
230    return g.findEdge(u, v, prev);
231  }
232
233  template <typename Graph>
234  inline typename Graph::Edge
235  _findEdge(Wrap<Graph> w,
236            typename Graph::Node u,
237            typename Graph::Node v,
238            typename Graph::Edge prev = INVALID) {
239    const Graph& g = w.value;
240    if (prev == INVALID) {
241      typename Graph::OutEdgeIt e(g, u);
242      while (e != INVALID && g.target(e) != v) ++e;
243      return e;
244    } else {
245      typename Graph::OutEdgeIt e(g, prev); ++e;
246      while (e != INVALID && g.target(e) != v) ++e;
247      return e;
248    }
249  }
250
251  /// \brief Finds an edge between two nodes of a graph.
252  ///
253  /// Finds an edge from node \c u to node \c v in graph \c g.
254  ///
255  /// If \c prev is \ref INVALID (this is the default value), then
256  /// it finds the first edge from \c u to \c v. Otherwise it looks for
257  /// the next edge from \c u to \c v after \c prev.
258  /// \return The found edge or \ref INVALID if there is no such an edge.
259  ///
260  /// Thus you can iterate through each edge from \c u to \c v as it follows.
261  /// \code
262  /// for(Edge e=findEdge(g,u,v);e!=INVALID;e=findEdge(g,u,v,e)) {
263  ///   ...
264  /// }
265  /// \endcode
266  // /// \todo We may want to use the "GraphBase"
267  // /// interface here...
268  template <typename Graph>
269  inline typename Graph::Edge findEdge(const Graph &g,
270                                       typename Graph::Node u,
271                                       typename Graph::Node v,
272                                       typename Graph::Edge prev = INVALID) {
273    return _findEdge<Graph>(g, u, v, prev);
274  }
275
276  /// \brief Iterator for iterating on edges connected the same nodes.
277  ///
278  /// Iterator for iterating on edges connected the same nodes. It is
279  /// higher level interface for the findEdge() function. You can
280  /// use it the following way:
281  /// \code
282  /// for (ConEdgeIt<Graph> it(g, src, trg); it != INVALID; ++it) {
283  ///   ...
284  /// }
285  /// \endcode
286  ///
287  /// \author Balazs Dezso
288  template <typename _Graph>
289  class ConEdgeIt : public _Graph::Edge {
290  public:
291
292    typedef _Graph Graph;
293    typedef typename Graph::Edge Parent;
294
295    typedef typename Graph::Edge Edge;
296    typedef typename Graph::Node Node;
297
298    /// \brief Constructor.
299    ///
300    /// Construct a new ConEdgeIt iterating on the edges which
301    /// connects the \c u and \c v node.
302    ConEdgeIt(const Graph& g, Node u, Node v) : graph(g) {
303      Parent::operator=(findEdge(graph, u, v));
304    }
305
306    /// \brief Constructor.
307    ///
308    /// Construct a new ConEdgeIt which continues the iterating from
309    /// the \c e edge.
310    ConEdgeIt(const Graph& g, Edge e) : Parent(e), graph(g) {}
311   
312    /// \brief Increment operator.
313    ///
314    /// It increments the iterator and gives back the next edge.
315    ConEdgeIt& operator++() {
316      Parent::operator=(findEdge(graph, graph.source(*this),
317                                 graph.target(*this), *this));
318      return *this;
319    }
320  private:
321    const Graph& graph;
322  };
323
324  template <typename Graph>
325  inline
326  typename enable_if<
327    typename Graph::FindEdgeTag,
328    typename Graph::UndirEdge>::type
329  _findUndirEdge(const Graph &g,
330            typename Graph::Node u, typename Graph::Node v,
331            typename Graph::UndirEdge prev = INVALID) {
332    return g.findUndirEdge(u, v, prev);
333  }
334
335  template <typename Graph>
336  inline typename Graph::UndirEdge
337  _findUndirEdge(Wrap<Graph> w,
338            typename Graph::Node u,
339            typename Graph::Node v,
340            typename Graph::UndirEdge prev = INVALID) {
341    const Graph& g = w.value;
342    if (prev == INVALID) {
343      typename Graph::OutEdgeIt e(g, u);
344      while (e != INVALID && g.target(e) != v) ++e;
345      return e;
346    } else {
347      typename Graph::OutEdgeIt e(g, g.direct(prev, u)); ++e;
348      while (e != INVALID && g.target(e) != v) ++e;
349      return e;
350    }
351  }
352
353  /// \brief Finds an undir edge between two nodes of a graph.
354  ///
355  /// Finds an undir edge from node \c u to node \c v in graph \c g.
356  ///
357  /// If \c prev is \ref INVALID (this is the default value), then
358  /// it finds the first edge from \c u to \c v. Otherwise it looks for
359  /// the next edge from \c u to \c v after \c prev.
360  /// \return The found edge or \ref INVALID if there is no such an edge.
361  ///
362  /// Thus you can iterate through each edge from \c u to \c v as it follows.
363  /// \code
364  /// for(UndirEdge e = findUndirEdge(g,u,v); e != INVALID;
365  ///     e = findUndirEdge(g,u,v,e)) {
366  ///   ...
367  /// }
368  /// \endcode
369  // /// \todo We may want to use the "GraphBase"
370  // /// interface here...
371  template <typename Graph>
372  inline typename Graph::UndirEdge
373  findUndirEdge(const Graph &g,
374                typename Graph::Node u,
375                typename Graph::Node v,
376                typename Graph::UndirEdge prev = INVALID) {
377    return _findUndirEdge<Graph>(g, u, v, prev);
378  }
379
380  /// \brief Iterator for iterating on undir edges connected the same nodes.
381  ///
382  /// Iterator for iterating on undir edges connected the same nodes. It is
383  /// higher level interface for the findUndirEdge() function. You can
384  /// use it the following way:
385  /// \code
386  /// for (ConUndirEdgeIt<Graph> it(g, src, trg); it != INVALID; ++it) {
387  ///   ...
388  /// }
389  /// \endcode
390  ///
391  /// \author Balazs Dezso
392  template <typename _Graph>
393  class ConUndirEdgeIt : public _Graph::UndirEdge {
394  public:
395
396    typedef _Graph Graph;
397    typedef typename Graph::UndirEdge Parent;
398
399    typedef typename Graph::UndirEdge UndirEdge;
400    typedef typename Graph::Node Node;
401
402    /// \brief Constructor.
403    ///
404    /// Construct a new ConUndirEdgeIt iterating on the edges which
405    /// connects the \c u and \c v node.
406    ConUndirEdgeIt(const Graph& g, Node u, Node v) : graph(g) {
407      Parent::operator=(findUndirEdge(graph, u, v));
408    }
409
410    /// \brief Constructor.
411    ///
412    /// Construct a new ConUndirEdgeIt which continues the iterating from
413    /// the \c e edge.
414    ConUndirEdgeIt(const Graph& g, UndirEdge e) : Parent(e), graph(g) {}
415   
416    /// \brief Increment operator.
417    ///
418    /// It increments the iterator and gives back the next edge.
419    ConUndirEdgeIt& operator++() {
420      Parent::operator=(findUndirEdge(graph, graph.source(*this),
421                                      graph.target(*this), *this));
422      return *this;
423    }
424  private:
425    const Graph& graph;
426  };
427
428  /// \brief Copy a map.
429  ///
430  /// This function copies the \c source map to the \c target map. It uses the
431  /// given iterator to iterate on the data structure and it uses the \c ref
432  /// mapping to convert the source's keys to the target's keys.
433  template <typename Target, typename Source,
434            typename ItemIt, typename Ref>         
435  void copyMap(Target& target, const Source& source,
436               ItemIt it, const Ref& ref) {
437    for (; it != INVALID; ++it) {
438      target[ref[it]] = source[it];
439    }
440  }
441
442  /// \brief Copy the source map to the target map.
443  ///
444  /// Copy the \c source map to the \c target map. It uses the given iterator
445  /// to iterate on the data structure.
446  template <typename Target, typename Source, typename ItemIt>     
447  void copyMap(Target& target, const Source& source, ItemIt it) {
448    for (; it != INVALID; ++it) {
449      target[it] = source[it];
450    }
451  }
452
453  /// \brief Class to copy a graph.
454  ///
455  /// Class to copy a graph to an other graph (duplicate a graph). The
456  /// simplest way of using it is through the \c copyGraph() function.
457  template <typename Target, typename Source>
458  class GraphCopy {
459  public:
460    typedef typename Source::Node Node;
461    typedef typename Source::NodeIt NodeIt;
462    typedef typename Source::Edge Edge;
463    typedef typename Source::EdgeIt EdgeIt;
464
465    typedef typename Source::template NodeMap<typename Target::Node>NodeRefMap;
466    typedef typename Source::template EdgeMap<typename Target::Edge>EdgeRefMap;
467
468    /// \brief Constructor for the GraphCopy.
469    ///
470    /// It copies the content of the \c _source graph into the
471    /// \c _target graph. It creates also two references, one beetween
472    /// the two nodeset and one beetween the two edgesets.
473    GraphCopy(Target& _target, const Source& _source)
474      : source(_source), target(_target),
475        nodeRefMap(_source), edgeRefMap(_source) {
476      for (NodeIt it(source); it != INVALID; ++it) {
477        nodeRefMap[it] = target.addNode();
478      }
479      for (EdgeIt it(source); it != INVALID; ++it) {
480        edgeRefMap[it] = target.addEdge(nodeRefMap[source.source(it)],
481                                        nodeRefMap[source.target(it)]);
482      }
483    }
484
485    /// \brief Copies the node references into the given map.
486    ///
487    /// Copies the node references into the given map.
488    template <typename NodeRef>
489    const GraphCopy& nodeRef(NodeRef& map) const {
490      for (NodeIt it(source); it != INVALID; ++it) {
491        map.set(it, nodeRefMap[it]);
492      }
493      return *this;
494    }
495
496    /// \brief Reverse and copies the node references into the given map.
497    ///
498    /// Reverse and copies the node references into the given map.
499    template <typename NodeRef>
500    const GraphCopy& nodeCrossRef(NodeRef& map) const {
501      for (NodeIt it(source); it != INVALID; ++it) {
502        map.set(nodeRefMap[it], it);
503      }
504      return *this;
505    }
506
507    /// \brief Copies the edge references into the given map.
508    ///
509    /// Copies the edge references into the given map.
510    template <typename EdgeRef>
511    const GraphCopy& edgeRef(EdgeRef& map) const {
512      for (EdgeIt it(source); it != INVALID; ++it) {
513        map.set(it, edgeRefMap[it]);
514      }
515      return *this;
516    }
517
518    /// \brief Reverse and copies the edge references into the given map.
519    ///
520    /// Reverse and copies the edge references into the given map.
521    template <typename EdgeRef>
522    const GraphCopy& edgeCrossRef(EdgeRef& map) const {
523      for (EdgeIt it(source); it != INVALID; ++it) {
524        map.set(edgeRefMap[it], it);
525      }
526      return *this;
527    }
528
529    /// \brief Make copy of the given map.
530    ///
531    /// Makes copy of the given map for the newly created graph.
532    /// The new map's key type is the target graph's node type,
533    /// and the copied map's key type is the source graph's node
534    /// type. 
535    template <typename TargetMap, typename SourceMap>
536    const GraphCopy& nodeMap(TargetMap& tMap, const SourceMap& sMap) const {
537      copyMap(tMap, sMap, NodeIt(source), nodeRefMap);
538      return *this;
539    }
540
541    /// \brief Make copy of the given map.
542    ///
543    /// Makes copy of the given map for the newly created graph.
544    /// The new map's key type is the target graph's edge type,
545    /// and the copied map's key type is the source graph's edge
546    /// type. 
547    template <typename TargetMap, typename SourceMap>
548    const GraphCopy& edgeMap(TargetMap& tMap, const SourceMap& sMap) const {
549      copyMap(tMap, sMap, EdgeIt(source), edgeRefMap);
550      return *this;
551    }
552
553    /// \brief Gives back the stored node references.
554    ///
555    /// Gives back the stored node references.
556    const NodeRefMap& nodeRef() const {
557      return nodeRefMap;
558    }
559
560    /// \brief Gives back the stored edge references.
561    ///
562    /// Gives back the stored edge references.
563    const EdgeRefMap& edgeRef() const {
564      return edgeRefMap;
565    }
566
567    void run() {}
568
569  private:
570   
571    const Source& source;
572    Target& target;
573
574    NodeRefMap nodeRefMap;
575    EdgeRefMap edgeRefMap;
576  };
577
578  /// \brief Copy a graph to an other graph.
579  ///
580  /// Copy a graph to an other graph.
581  /// The usage of the function:
582  ///
583  /// \code
584  /// copyGraph(trg, src).nodeRef(nr).edgeCrossRef(ecr);
585  /// \endcode
586  ///
587  /// After the copy the \c nr map will contain the mapping from the
588  /// source graph's nodes to the target graph's nodes and the \c ecr will
589  /// contain the mapping from the target graph's edges to the source's
590  /// edges.
591  template <typename Target, typename Source>
592  GraphCopy<Target, Source> copyGraph(Target& target, const Source& source) {
593    return GraphCopy<Target, Source>(target, source);
594  }
595
596  /// \brief Class to copy an undirected graph.
597  ///
598  /// Class to copy an undirected graph to an other graph (duplicate a graph).
599  /// The simplest way of using it is through the \c copyUndirGraph() function.
600  template <typename Target, typename Source>
601  class UndirGraphCopy {
602  public:
603    typedef typename Source::Node Node;
604    typedef typename Source::NodeIt NodeIt;
605    typedef typename Source::Edge Edge;
606    typedef typename Source::EdgeIt EdgeIt;
607    typedef typename Source::UndirEdge UndirEdge;
608    typedef typename Source::UndirEdgeIt UndirEdgeIt;
609
610    typedef typename Source::
611    template NodeMap<typename Target::Node> NodeRefMap;
612   
613    typedef typename Source::
614    template UndirEdgeMap<typename Target::UndirEdge> UndirEdgeRefMap;
615
616  private:
617
618    struct EdgeRefMap {
619      EdgeRefMap(UndirGraphCopy& _gc) : gc(_gc) {}
620      typedef typename Source::Edge Key;
621      typedef typename Target::Edge Value;
622
623      Value operator[](const Key& key) {
624        return gc.target.direct(gc.undirEdgeRef[key],
625                                gc.target.direction(key));
626      }
627     
628      UndirGraphCopy& gc;
629    };
630   
631  public:
632
633    /// \brief Constructor for the UndirGraphCopy.
634    ///
635    /// It copies the content of the \c _source graph into the
636    /// \c _target graph. It creates also two references, one beetween
637    /// the two nodeset and one beetween the two edgesets.
638    UndirGraphCopy(Target& _target, const Source& _source)
639      : source(_source), target(_target),
640        nodeRefMap(_source), edgeRefMap(*this), undirEdgeRefMap(_source) {
641      for (NodeIt it(source); it != INVALID; ++it) {
642        nodeRefMap[it] = target.addNode();
643      }
644      for (UndirEdgeIt it(source); it != INVALID; ++it) {
645        undirEdgeRefMap[it] = target.addEdge(nodeRefMap[source.source(it)],
646                                        nodeRefMap[source.target(it)]);
647      }
648    }
649
650    /// \brief Copies the node references into the given map.
651    ///
652    /// Copies the node references into the given map.
653    template <typename NodeRef>
654    const UndirGraphCopy& nodeRef(NodeRef& map) const {
655      for (NodeIt it(source); it != INVALID; ++it) {
656        map.set(it, nodeRefMap[it]);
657      }
658      return *this;
659    }
660
661    /// \brief Reverse and copies the node references into the given map.
662    ///
663    /// Reverse and copies the node references into the given map.
664    template <typename NodeRef>
665    const UndirGraphCopy& nodeCrossRef(NodeRef& map) const {
666      for (NodeIt it(source); it != INVALID; ++it) {
667        map.set(nodeRefMap[it], it);
668      }
669      return *this;
670    }
671
672    /// \brief Copies the edge references into the given map.
673    ///
674    /// Copies the edge references into the given map.
675    template <typename EdgeRef>
676    const UndirGraphCopy& edgeRef(EdgeRef& map) const {
677      for (EdgeIt it(source); it != INVALID; ++it) {
678        map.set(edgeRefMap[it], it);
679      }
680      return *this;
681    }
682
683    /// \brief Reverse and copies the undirected edge references into the
684    /// given map.
685    ///
686    /// Reverse and copies the undirected edge references into the given map.
687    template <typename EdgeRef>
688    const UndirGraphCopy& edgeCrossRef(EdgeRef& map) const {
689      for (EdgeIt it(source); it != INVALID; ++it) {
690        map.set(it, edgeRefMap[it]);
691      }
692      return *this;
693    }
694
695    /// \brief Copies the undirected edge references into the given map.
696    ///
697    /// Copies the undirected edge references into the given map.
698    template <typename EdgeRef>
699    const UndirGraphCopy& undirEdgeRef(EdgeRef& map) const {
700      for (UndirEdgeIt it(source); it != INVALID; ++it) {
701        map.set(it, undirEdgeRefMap[it]);
702      }
703      return *this;
704    }
705
706    /// \brief Reverse and copies the undirected edge references into the
707    /// given map.
708    ///
709    /// Reverse and copies the undirected edge references into the given map.
710    template <typename EdgeRef>
711    const UndirGraphCopy& undirEdgeCrossRef(EdgeRef& map) const {
712      for (UndirEdgeIt it(source); it != INVALID; ++it) {
713        map.set(undirEdgeRefMap[it], it);
714      }
715      return *this;
716    }
717
718    /// \brief Make copy of the given map.
719    ///
720    /// Makes copy of the given map for the newly created graph.
721    /// The new map's key type is the target graph's node type,
722    /// and the copied map's key type is the source graph's node
723    /// type. 
724    template <typename TargetMap, typename SourceMap>
725    const UndirGraphCopy& nodeMap(TargetMap& tMap,
726                                  const SourceMap& sMap) const {
727      copyMap(tMap, sMap, NodeIt(source), nodeRefMap);
728      return *this;
729    }
730
731    /// \brief Make copy of the given map.
732    ///
733    /// Makes copy of the given map for the newly created graph.
734    /// The new map's key type is the target graph's edge type,
735    /// and the copied map's key type is the source graph's edge
736    /// type. 
737    template <typename TargetMap, typename SourceMap>
738    const UndirGraphCopy& edgeMap(TargetMap& tMap,
739                                  const SourceMap& sMap) const {
740      copyMap(tMap, sMap, EdgeIt(source), edgeRefMap);
741      return *this;
742    }
743
744    /// \brief Make copy of the given map.
745    ///
746    /// Makes copy of the given map for the newly created graph.
747    /// The new map's key type is the target graph's edge type,
748    /// and the copied map's key type is the source graph's edge
749    /// type. 
750    template <typename TargetMap, typename SourceMap>
751    const UndirGraphCopy& undirEdgeMap(TargetMap& tMap,
752                                  const SourceMap& sMap) const {
753      copyMap(tMap, sMap, UndirEdgeIt(source), undirEdgeRefMap);
754      return *this;
755    }
756
757    /// \brief Gives back the stored node references.
758    ///
759    /// Gives back the stored node references.
760    const NodeRefMap& nodeRef() const {
761      return nodeRefMap;
762    }
763
764    /// \brief Gives back the stored edge references.
765    ///
766    /// Gives back the stored edge references.
767    const EdgeRefMap& edgeRef() const {
768      return edgeRefMap;
769    }
770
771    /// \brief Gives back the stored undir edge references.
772    ///
773    /// Gives back the stored undir edge references.
774    const UndirEdgeRefMap& undirEdgeRef() const {
775      return undirEdgeRefMap;
776    }
777
778    void run() {}
779
780  private:
781   
782    const Source& source;
783    Target& target;
784
785    NodeRefMap nodeRefMap;
786    EdgeRefMap edgeRefMap;
787    UndirEdgeRefMap undirEdgeRefMap;
788  };
789
790  /// \brief Copy a graph to an other graph.
791  ///
792  /// Copy a graph to an other graph.
793  /// The usage of the function:
794  ///
795  /// \code
796  /// copyGraph(trg, src).nodeRef(nr).edgeCrossRef(ecr);
797  /// \endcode
798  ///
799  /// After the copy the \c nr map will contain the mapping from the
800  /// source graph's nodes to the target graph's nodes and the \c ecr will
801  /// contain the mapping from the target graph's edges to the source's
802  /// edges.
803  template <typename Target, typename Source>
804  UndirGraphCopy<Target, Source>
805  copyUndirGraph(Target& target, const Source& source) {
806    return UndirGraphCopy<Target, Source>(target, source);
807  }
808
809
810  /// @}
811
812  /// \addtogroup graph_maps
813  /// @{
814
815  /// Provides an immutable and unique id for each item in the graph.
816
817  /// The IdMap class provides a unique and immutable id for each item of the
818  /// same type (e.g. node) in the graph. This id is <ul><li>\b unique:
819  /// different items (nodes) get different ids <li>\b immutable: the id of an
820  /// item (node) does not change (even if you delete other nodes).  </ul>
821  /// Through this map you get access (i.e. can read) the inner id values of
822  /// the items stored in the graph. This map can be inverted with its member
823  /// class \c InverseMap.
824  ///
825  template <typename _Graph, typename _Item>
826  class IdMap {
827  public:
828    typedef _Graph Graph;
829    typedef int Value;
830    typedef _Item Item;
831    typedef _Item Key;
832
833    /// \brief Constructor.
834    ///
835    /// Constructor for creating id map.
836    IdMap(const Graph& _graph) : graph(&_graph) {}
837
838    /// \brief Gives back the \e id of the item.
839    ///
840    /// Gives back the immutable and unique \e id of the map.
841    int operator[](const Item& item) const { return graph->id(item);}
842
843
844  private:
845    const Graph* graph;
846
847  public:
848
849    /// \brief The class represents the inverse of its owner (IdMap).
850    ///
851    /// The class represents the inverse of its owner (IdMap).
852    /// \see inverse()
853    class InverseMap {
854    public:
855
856      /// \brief Constructor.
857      ///
858      /// Constructor for creating an id-to-item map.
859      InverseMap(const Graph& _graph) : graph(&_graph) {}
860
861      /// \brief Constructor.
862      ///
863      /// Constructor for creating an id-to-item map.
864      InverseMap(const IdMap& idMap) : graph(idMap.graph) {}
865
866      /// \brief Gives back the given item from its id.
867      ///
868      /// Gives back the given item from its id.
869      ///
870      Item operator[](int id) const { return graph->fromId(id, Item());}
871    private:
872      const Graph* graph;
873    };
874
875    /// \brief Gives back the inverse of the map.
876    ///
877    /// Gives back the inverse of the IdMap.
878    InverseMap inverse() const { return InverseMap(*graph);}
879
880  };
881
882 
883  /// \brief General invertable graph-map type.
884
885  /// This type provides simple invertable graph-maps.
886  /// The InvertableMap wraps an arbitrary ReadWriteMap
887  /// and if a key is set to a new value then store it
888  /// in the inverse map.
889  /// \param _Graph The graph type.
890  /// \param _Item The item type of the graph.
891  /// \param _Value The value type of the map.
892#ifndef DOXYGEN
893  /// \param _Map A ReadWriteMap mapping from the item type to integer.
894  template <
895    typename _Graph, typename _Item, typename _Value, typename _Map
896    = typename ItemSetTraits<_Graph, _Item>::template Map<_Value>::Parent
897  >
898#else
899  template <typename _Graph, typename _Item, typename _Value>
900#endif
901  class InvertableMap : protected _Map {
902
903  public:
904 
905    typedef _Map Map;
906    typedef _Graph Graph;
907
908    /// The key type of InvertableMap (Node, Edge, UndirEdge).
909    typedef typename _Map::Key Key;
910    /// The value type of the InvertableMap.
911    typedef typename _Map::Value Value;
912
913    /// \brief Constructor.
914    ///
915    /// Construct a new InvertableMap for the graph.
916    ///
917    InvertableMap(const Graph& graph) : Map(graph) {}
918   
919    /// \brief The setter function of the map.
920    ///
921    /// Sets the mapped value.
922    void set(const Key& key, const Value& val) {
923      Value oldval = Map::operator[](key);
924      typename Container::iterator it = invMap.find(oldval);
925      if (it != invMap.end() && it->second == key) {
926        invMap.erase(it);
927      }     
928      invMap.insert(make_pair(val, key));
929      Map::set(key, val);
930    }
931
932    /// \brief The getter function of the map.
933    ///
934    /// It gives back the value associated with the key.
935    Value operator[](const Key& key) const {
936      return Map::operator[](key);
937    }
938
939  protected:
940
941    /// \brief Erase the key from the map.
942    ///
943    /// Erase the key to the map. It is called by the
944    /// \c AlterationNotifier.
945    virtual void erase(const Key& key) {
946      Value val = Map::operator[](key);
947      typename Container::iterator it = invMap.find(val);
948      if (it != invMap.end() && it->second == key) {
949        invMap.erase(it);
950      }
951      Map::erase(key);
952    }
953
954    /// \brief Erase more keys from the map.
955    ///
956    /// Erase more keys from the map. It is called by the
957    /// \c AlterationNotifier.
958    virtual void erase(const std::vector<Key>& keys) {
959      for (int i = 0; i < (int)keys.size(); ++i) {
960        Value val = Map::operator[](keys[i]);
961        typename Container::iterator it = invMap.find(val);
962        if (it != invMap.end() && it->second == keys[i]) {
963          invMap.erase(it);
964        }
965      }
966      Map::erase(keys);
967    }
968
969    /// \brief Clear the keys from the map and inverse map.
970    ///
971    /// Clear the keys from the map and inverse map. It is called by the
972    /// \c AlterationNotifier.
973    virtual void clear() {
974      invMap.clear();
975      Map::clear();
976    }
977
978  private:
979   
980    typedef std::map<Value, Key> Container;
981    Container invMap;   
982
983  public:
984
985    /// \brief The inverse map type.
986    ///
987    /// The inverse of this map. The subscript operator of the map
988    /// gives back always the item what was last assigned to the value.
989    class InverseMap {
990    public:
991      /// \brief Constructor of the InverseMap.
992      ///
993      /// Constructor of the InverseMap.
994      InverseMap(const InvertableMap& _inverted) : inverted(_inverted) {}
995
996      /// The value type of the InverseMap.
997      typedef typename InvertableMap::Key Value;
998      /// The key type of the InverseMap.
999      typedef typename InvertableMap::Value Key;
1000
1001      /// \brief Subscript operator.
1002      ///
1003      /// Subscript operator. It gives back always the item
1004      /// what was last assigned to the value.
1005      Value operator[](const Key& key) const {
1006        typename Container::const_iterator it = inverted.invMap.find(key);
1007        return it->second;
1008      }
1009     
1010    private:
1011      const InvertableMap& inverted;
1012    };
1013
1014    /// \brief It gives back the just readeable inverse map.
1015    ///
1016    /// It gives back the just readeable inverse map.
1017    InverseMap inverse() const {
1018      return InverseMap(*this);
1019    }
1020
1021
1022   
1023  };
1024
1025  /// \brief Provides a mutable, continuous and unique descriptor for each
1026  /// item in the graph.
1027  ///
1028  /// The DescriptorMap class provides a unique and continuous (but mutable)
1029  /// descriptor (id) for each item of the same type (e.g. node) in the
1030  /// graph. This id is <ul><li>\b unique: different items (nodes) get
1031  /// different ids <li>\b continuous: the range of the ids is the set of
1032  /// integers between 0 and \c n-1, where \c n is the number of the items of
1033  /// this type (e.g. nodes) (so the id of a node can change if you delete an
1034  /// other node, i.e. this id is mutable).  </ul> This map can be inverted
1035  /// with its member class \c InverseMap.
1036  ///
1037  /// \param _Graph The graph class the \c DescriptorMap belongs to.
1038  /// \param _Item The Item is the Key of the Map. It may be Node, Edge or
1039  /// UndirEdge.
1040#ifndef DOXYGEN
1041  /// \param _Map A ReadWriteMap mapping from the item type to integer.
1042  template <
1043    typename _Graph, typename _Item, typename _Map
1044    = typename ItemSetTraits<_Graph, _Item>::template Map<int>::Parent
1045  >
1046#else
1047  template <typename _Graph, typename _Item>
1048#endif
1049  class DescriptorMap : protected _Map {
1050
1051    typedef _Item Item;
1052    typedef _Map Map;
1053
1054  public:
1055    /// The graph class of DescriptorMap.
1056    typedef _Graph Graph;
1057
1058    /// The key type of DescriptorMap (Node, Edge, UndirEdge).
1059    typedef typename _Map::Key Key;
1060    /// The value type of DescriptorMap.
1061    typedef typename _Map::Value Value;
1062
1063    /// \brief Constructor.
1064    ///
1065    /// Constructor for descriptor map.
1066    DescriptorMap(const Graph& _graph) : Map(_graph) {
1067      build();
1068    }
1069
1070  protected:
1071
1072    /// \brief Add a new key to the map.
1073    ///
1074    /// Add a new key to the map. It is called by the
1075    /// \c AlterationNotifier.
1076    virtual void add(const Item& item) {
1077      Map::add(item);
1078      Map::set(item, invMap.size());
1079      invMap.push_back(item);
1080    }
1081
1082    /// \brief Add more new keys to the map.
1083    ///
1084    /// Add more new keys to the map. It is called by the
1085    /// \c AlterationNotifier.
1086    virtual void add(const std::vector<Item>& items) {
1087      Map::add(items);
1088      for (int i = 0; i < (int)items.size(); ++i) {
1089        Map::set(items[i], invMap.size());
1090        invMap.push_back(items[i]);
1091      }
1092    }
1093
1094    /// \brief Erase the key from the map.
1095    ///
1096    /// Erase the key from the map. It is called by the
1097    /// \c AlterationNotifier.
1098    virtual void erase(const Item& item) {
1099      Map::set(invMap.back(), Map::operator[](item));
1100      invMap[Map::operator[](item)] = invMap.back();
1101      invMap.pop_back();
1102      Map::erase(item);
1103    }
1104
1105    /// \brief Erase more keys from the map.
1106    ///
1107    /// Erase more keys from the map. It is called by the
1108    /// \c AlterationNotifier.
1109    virtual void erase(const std::vector<Item>& items) {
1110      for (int i = 0; i < (int)items.size(); ++i) {
1111        Map::set(invMap.back(), Map::operator[](items[i]));
1112        invMap[Map::operator[](items[i])] = invMap.back();
1113        invMap.pop_back();
1114      }
1115      Map::erase(items);
1116    }
1117
1118    /// \brief Build the unique map.
1119    ///
1120    /// Build the unique map. It is called by the
1121    /// \c AlterationNotifier.
1122    virtual void build() {
1123      Map::build();
1124      Item it;
1125      const typename Map::Graph* graph = Map::getGraph();
1126      for (graph->first(it); it != INVALID; graph->next(it)) {
1127        Map::set(it, invMap.size());
1128        invMap.push_back(it);   
1129      }     
1130    }
1131   
1132    /// \brief Clear the keys from the map.
1133    ///
1134    /// Clear the keys from the map. It is called by the
1135    /// \c AlterationNotifier.
1136    virtual void clear() {
1137      invMap.clear();
1138      Map::clear();
1139    }
1140
1141  public:
1142
1143    /// \brief Swaps the position of the two items in the map.
1144    ///
1145    /// Swaps the position of the two items in the map.
1146    void swap(const Item& p, const Item& q) {
1147      int pi = Map::operator[](p);
1148      int qi = Map::operator[](q);
1149      Map::set(p, qi);
1150      invMap[qi] = p;
1151      Map::set(q, pi);
1152      invMap[pi] = q;
1153    }
1154
1155    /// \brief Gives back the \e descriptor of the item.
1156    ///
1157    /// Gives back the mutable and unique \e descriptor of the map.
1158    int operator[](const Item& item) const {
1159      return Map::operator[](item);
1160    }
1161   
1162  private:
1163
1164    typedef std::vector<Item> Container;
1165    Container invMap;
1166
1167  public:
1168    /// \brief The inverse map type of DescriptorMap.
1169    ///
1170    /// The inverse map type of DescriptorMap.
1171    class InverseMap {
1172    public:
1173      /// \brief Constructor of the InverseMap.
1174      ///
1175      /// Constructor of the InverseMap.
1176      InverseMap(const DescriptorMap& _inverted)
1177        : inverted(_inverted) {}
1178
1179
1180      /// The value type of the InverseMap.
1181      typedef typename DescriptorMap::Key Value;
1182      /// The key type of the InverseMap.
1183      typedef typename DescriptorMap::Value Key;
1184
1185      /// \brief Subscript operator.
1186      ///
1187      /// Subscript operator. It gives back the item
1188      /// that the descriptor belongs to currently.
1189      Value operator[](const Key& key) const {
1190        return inverted.invMap[key];
1191      }
1192
1193      /// \brief Size of the map.
1194      ///
1195      /// Returns the size of the map.
1196      int size() const {
1197        return inverted.invMap.size();
1198      }
1199     
1200    private:
1201      const DescriptorMap& inverted;
1202    };
1203
1204    /// \brief Gives back the inverse of the map.
1205    ///
1206    /// Gives back the inverse of the map.
1207    const InverseMap inverse() const {
1208      return InverseMap(*this);
1209    }
1210  };
1211
1212  /// \brief Returns the source of the given edge.
1213  ///
1214  /// The SourceMap gives back the source Node of the given edge.
1215  /// \author Balazs Dezso
1216  template <typename Graph>
1217  class SourceMap {
1218  public:
1219
1220    typedef typename Graph::Node Value;
1221    typedef typename Graph::Edge Key;
1222
1223    /// \brief Constructor
1224    ///
1225    /// Constructor
1226    /// \param _graph The graph that the map belongs to.
1227    SourceMap(const Graph& _graph) : graph(_graph) {}
1228
1229    /// \brief The subscript operator.
1230    ///
1231    /// The subscript operator.
1232    /// \param edge The edge
1233    /// \return The source of the edge
1234    Value operator[](const Key& edge) const {
1235      return graph.source(edge);
1236    }
1237
1238  private:
1239    const Graph& graph;
1240  };
1241
1242  /// \brief Returns a \ref SourceMap class
1243  ///
1244  /// This function just returns an \ref SourceMap class.
1245  /// \relates SourceMap
1246  template <typename Graph>
1247  inline SourceMap<Graph> sourceMap(const Graph& graph) {
1248    return SourceMap<Graph>(graph);
1249  }
1250
1251  /// \brief Returns the target of the given edge.
1252  ///
1253  /// The TargetMap gives back the target Node of the given edge.
1254  /// \author Balazs Dezso
1255  template <typename Graph>
1256  class TargetMap {
1257  public:
1258
1259    typedef typename Graph::Node Value;
1260    typedef typename Graph::Edge Key;
1261
1262    /// \brief Constructor
1263    ///
1264    /// Constructor
1265    /// \param _graph The graph that the map belongs to.
1266    TargetMap(const Graph& _graph) : graph(_graph) {}
1267
1268    /// \brief The subscript operator.
1269    ///
1270    /// The subscript operator.
1271    /// \param e The edge
1272    /// \return The target of the edge
1273    Value operator[](const Key& e) const {
1274      return graph.target(e);
1275    }
1276
1277  private:
1278    const Graph& graph;
1279  };
1280
1281  /// \brief Returns a \ref TargetMap class
1282  ///
1283  /// This function just returns a \ref TargetMap class.
1284  /// \relates TargetMap
1285  template <typename Graph>
1286  inline TargetMap<Graph> targetMap(const Graph& graph) {
1287    return TargetMap<Graph>(graph);
1288  }
1289
1290  /// \brief Returns the "forward" directed edge view of an undirected edge.
1291  ///
1292  /// Returns the "forward" directed edge view of an undirected edge.
1293  /// \author Balazs Dezso
1294  template <typename Graph>
1295  class ForwardMap {
1296  public:
1297
1298    typedef typename Graph::Edge Value;
1299    typedef typename Graph::UndirEdge Key;
1300
1301    /// \brief Constructor
1302    ///
1303    /// Constructor
1304    /// \param _graph The graph that the map belongs to.
1305    ForwardMap(const Graph& _graph) : graph(_graph) {}
1306
1307    /// \brief The subscript operator.
1308    ///
1309    /// The subscript operator.
1310    /// \param key An undirected edge
1311    /// \return The "forward" directed edge view of undirected edge
1312    Value operator[](const Key& key) const {
1313      return graph.direct(key, true);
1314    }
1315
1316  private:
1317    const Graph& graph;
1318  };
1319
1320  /// \brief Returns a \ref ForwardMap class
1321  ///
1322  /// This function just returns an \ref ForwardMap class.
1323  /// \relates ForwardMap
1324  template <typename Graph>
1325  inline ForwardMap<Graph> forwardMap(const Graph& graph) {
1326    return ForwardMap<Graph>(graph);
1327  }
1328
1329  /// \brief Returns the "backward" directed edge view of an undirected edge.
1330  ///
1331  /// Returns the "backward" directed edge view of an undirected edge.
1332  /// \author Balazs Dezso
1333  template <typename Graph>
1334  class BackwardMap {
1335  public:
1336
1337    typedef typename Graph::Edge Value;
1338    typedef typename Graph::UndirEdge Key;
1339
1340    /// \brief Constructor
1341    ///
1342    /// Constructor
1343    /// \param _graph The graph that the map belongs to.
1344    BackwardMap(const Graph& _graph) : graph(_graph) {}
1345
1346    /// \brief The subscript operator.
1347    ///
1348    /// The subscript operator.
1349    /// \param key An undirected edge
1350    /// \return The "backward" directed edge view of undirected edge
1351    Value operator[](const Key& key) const {
1352      return graph.direct(key, false);
1353    }
1354
1355  private:
1356    const Graph& graph;
1357  };
1358
1359  /// \brief Returns a \ref BackwardMap class
1360
1361  /// This function just returns a \ref BackwardMap class.
1362  /// \relates BackwardMap
1363  template <typename Graph>
1364  inline BackwardMap<Graph> backwardMap(const Graph& graph) {
1365    return BackwardMap<Graph>(graph);
1366  }
1367
1368  /// \brief Potential difference map
1369  ///
1370  /// If there is an potential map on the nodes then we
1371  /// can get an edge map as we get the substraction of the
1372  /// values of the target and source.
1373  template <typename Graph, typename NodeMap>
1374  class PotentialDifferenceMap {
1375  public:
1376    typedef typename Graph::Edge Key;
1377    typedef typename NodeMap::Value Value;
1378
1379    /// \brief Constructor
1380    ///
1381    /// Contructor of the map
1382    PotentialDifferenceMap(const Graph& _graph, const NodeMap& _potential)
1383      : graph(_graph), potential(_potential) {}
1384
1385    /// \brief Const subscription operator
1386    ///
1387    /// Const subscription operator
1388    Value operator[](const Key& edge) const {
1389      return potential[graph.target(edge)] - potential[graph.source(edge)];
1390    }
1391
1392  private:
1393    const Graph& graph;
1394    const NodeMap& potential;
1395  };
1396
1397  /// \brief Just returns a PotentialDifferenceMap
1398  ///
1399  /// Just returns a PotentialDifferenceMap
1400  /// \relates PotentialDifferenceMap
1401  template <typename Graph, typename NodeMap>
1402  PotentialDifferenceMap<Graph, NodeMap>
1403  potentialDifferenceMap(const Graph& graph, const NodeMap& potential) {
1404    return PotentialDifferenceMap<Graph, NodeMap>(graph, potential);
1405  }
1406
1407  /// \brief Map of the node in-degrees.
1408  ///
1409  /// This map returns the in-degree of a node. Once it is constructed,
1410  /// the degrees are stored in a standard NodeMap, so each query is done
1411  /// in constant time. On the other hand, the values are updated automatically
1412  /// whenever the graph changes.
1413  ///
1414  /// \warning Besides addNode() and addEdge(), a graph structure may provide
1415  /// alternative ways to modify the graph. The correct behavior of InDegMap
1416  /// is not guarantied if these additional features are used. For example
1417  /// the functions \ref ListGraph::changeSource() "changeSource()",
1418  /// \ref ListGraph::changeTarget() "changeTarget()" and
1419  /// \ref ListGraph::reverseEdge() "reverseEdge()"
1420  /// of \ref ListGraph will \e not update the degree values correctly.
1421  ///
1422  /// \sa OutDegMap
1423
1424  template <typename _Graph>
1425  class InDegMap 
1426    : protected AlterationNotifier<typename _Graph::Edge>::ObserverBase {
1427
1428  public:
1429   
1430    typedef _Graph Graph;
1431    typedef int Value;
1432    typedef typename Graph::Node Key;
1433
1434  private:
1435
1436    class AutoNodeMap : public Graph::template NodeMap<int> {
1437    public:
1438
1439      typedef typename Graph::template NodeMap<int> Parent;
1440
1441      typedef typename Parent::Key Key;
1442      typedef typename Parent::Value Value;
1443     
1444      AutoNodeMap(const Graph& graph) : Parent(graph, 0) {}
1445     
1446      virtual void add(const Key& key) {
1447        Parent::add(key);
1448        Parent::set(key, 0);
1449      }
1450      virtual void add(const std::vector<Key>& keys) {
1451        Parent::add(keys);
1452        for (int i = 0; i < (int)keys.size(); ++i) {
1453          Parent::set(keys[i], 0);
1454        }
1455      }
1456    };
1457
1458  public:
1459
1460    /// \brief Constructor.
1461    ///
1462    /// Constructor for creating in-degree map.
1463    InDegMap(const Graph& _graph) : graph(_graph), deg(_graph) {
1464      AlterationNotifier<typename _Graph::Edge>
1465        ::ObserverBase::attach(graph.getNotifier(typename _Graph::Edge()));
1466     
1467      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1468        deg[it] = countInEdges(graph, it);
1469      }
1470    }
1471
1472    virtual ~InDegMap() {
1473      AlterationNotifier<typename _Graph::Edge>::
1474        ObserverBase::detach();
1475    }
1476   
1477    /// Gives back the in-degree of a Node.
1478    int operator[](const Key& key) const {
1479      return deg[key];
1480    }
1481
1482  protected:
1483   
1484    typedef typename Graph::Edge Edge;
1485
1486    virtual void add(const Edge& edge) {
1487      ++deg[graph.target(edge)];
1488    }
1489
1490    virtual void erase(const Edge& edge) {
1491      --deg[graph.target(edge)];
1492    }
1493
1494    virtual void build() {
1495      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1496        deg[it] = countInEdges(graph, it);
1497      }     
1498    }
1499
1500    virtual void clear() {
1501      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1502        deg[it] = 0;
1503      }
1504    }
1505  private:
1506   
1507    const _Graph& graph;
1508    AutoNodeMap deg;
1509  };
1510
1511  /// \brief Map of the node out-degrees.
1512  ///
1513  /// This map returns the out-degree of a node. Once it is constructed,
1514  /// the degrees are stored in a standard NodeMap, so each query is done
1515  /// in constant time. On the other hand, the values are updated automatically
1516  /// whenever the graph changes.
1517  ///
1518  /// \warning Besides addNode() and addEdge(), a graph structure may provide
1519  /// alternative ways to modify the graph. The correct behavior of OutDegMap
1520  /// is not guarantied if these additional features are used. For example
1521  /// the functions \ref ListGraph::changeSource() "changeSource()",
1522  /// \ref ListGraph::changeTarget() "changeTarget()" and
1523  /// \ref ListGraph::reverseEdge() "reverseEdge()"
1524  /// of \ref ListGraph will \e not update the degree values correctly.
1525  ///
1526  /// \sa InDegMap
1527
1528  template <typename _Graph>
1529  class OutDegMap 
1530    : protected AlterationNotifier<typename _Graph::Edge>::ObserverBase {
1531
1532  public:
1533   
1534    typedef _Graph Graph;
1535    typedef int Value;
1536    typedef typename Graph::Node Key;
1537
1538  private:
1539
1540    class AutoNodeMap : public Graph::template NodeMap<int> {
1541    public:
1542
1543      typedef typename Graph::template NodeMap<int> Parent;
1544
1545      typedef typename Parent::Key Key;
1546      typedef typename Parent::Value Value;
1547     
1548      AutoNodeMap(const Graph& graph) : Parent(graph, 0) {}
1549     
1550      virtual void add(const Key& key) {
1551        Parent::add(key);
1552        Parent::set(key, 0);
1553      }
1554      virtual void add(const std::vector<Key>& keys) {
1555        Parent::add(keys);
1556        for (int i = 0; i < (int)keys.size(); ++i) {
1557          Parent::set(keys[i], 0);
1558        }
1559      }
1560    };
1561
1562  public:
1563
1564    /// \brief Constructor.
1565    ///
1566    /// Constructor for creating out-degree map.
1567    OutDegMap(const Graph& _graph) : graph(_graph), deg(_graph) {
1568      AlterationNotifier<typename _Graph::Edge>
1569        ::ObserverBase::attach(graph.getNotifier(typename _Graph::Edge()));
1570     
1571      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1572        deg[it] = countOutEdges(graph, it);
1573      }
1574    }
1575
1576    virtual ~OutDegMap() {
1577      AlterationNotifier<typename _Graph::Edge>::
1578        ObserverBase::detach();
1579    }
1580   
1581    /// Gives back the in-degree of a Node.
1582    int operator[](const Key& key) const {
1583      return deg[key];
1584    }
1585
1586  protected:
1587   
1588    typedef typename Graph::Edge Edge;
1589
1590    virtual void add(const Edge& edge) {
1591      ++deg[graph.source(edge)];
1592    }
1593
1594    virtual void erase(const Edge& edge) {
1595      --deg[graph.source(edge)];
1596    }
1597
1598    virtual void build() {
1599      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1600        deg[it] = countOutEdges(graph, it);
1601      }     
1602    }
1603
1604    virtual void clear() {
1605      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1606        deg[it] = 0;
1607      }
1608    }
1609  private:
1610   
1611    const _Graph& graph;
1612    AutoNodeMap deg;
1613  };
1614
1615
1616  /// @}
1617
1618} //END OF NAMESPACE LEMON
1619
1620#endif
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