COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/graph_utils.h @ 1679:e825655c24a4

Last change on this file since 1679:e825655c24a4 was 1679:e825655c24a4, checked in by Balazs Dezso, 14 years ago

Some bugfixes.

File size: 35.2 KB
Line 
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
24#include <lemon/invalid.h>
25#include <lemon/utility.h>
26#include <lemon/maps.h>
27#include <lemon/bits/alteration_notifier.h>
28
29///\ingroup gutils
30///\file
31///\brief Graph utilities.
32///
33///
34
35
36namespace lemon {
37
38  /// \addtogroup gutils
39  /// @{
40
41  /// \brief Function to count the items in the graph.
42  ///
43  /// This function counts the items (nodes, edges etc) in the graph.
44  /// The complexity of the function is O(n) because
45  /// it iterates on all of the items.
46
47  template <typename Graph, typename ItemIt>
48  inline int countItems(const Graph& g) {
49    int num = 0;
50    for (ItemIt it(g); it != INVALID; ++it) {
51      ++num;
52    }
53    return num;
54  }
55
56  // Node counting:
57
58  template <typename Graph>
59  inline
60  typename enable_if<typename Graph::NodeNumTag, int>::type
61  _countNodes(const Graph &g) {
62    return g.nodeNum();
63  }
64
65  template <typename Graph>
66  inline int _countNodes(Wrap<Graph> w) {
67    return countItems<Graph, typename Graph::NodeIt>(w.value);
68  }
69
70  /// \brief Function to count the nodes in the graph.
71  ///
72  /// This function counts the nodes in the graph.
73  /// The complexity of the function is O(n) but for some
74  /// graph structures it is specialized to run in O(1).
75  ///
76  /// \todo refer how to specialize it
77
78  template <typename Graph>
79  inline int countNodes(const Graph& g) {
80    return _countNodes<Graph>(g);
81  }
82
83  // Edge counting:
84
85  template <typename Graph>
86  inline
87  typename enable_if<typename Graph::EdgeNumTag, int>::type
88  _countEdges(const Graph &g) {
89    return g.edgeNum();
90  }
91
92  template <typename Graph>
93  inline int _countEdges(Wrap<Graph> w) {
94    return countItems<Graph, typename Graph::EdgeIt>(w.value);
95  }
96
97  /// \brief Function to count the edges in the graph.
98  ///
99  /// This function counts the edges in the graph.
100  /// The complexity of the function is O(e) but for some
101  /// graph structures it is specialized to run in O(1).
102
103  template <typename Graph>
104  inline int countEdges(const Graph& g) {
105    return _countEdges<Graph>(g);
106  }
107
108  // Undirected edge counting:
109
110  template <typename Graph>
111  inline
112  typename enable_if<typename Graph::EdgeNumTag, int>::type
113  _countUndirEdges(const Graph &g) {
114    return g.undirEdgeNum();
115  }
116
117  template <typename Graph>
118  inline int _countUndirEdges(Wrap<Graph> w) {
119    return countItems<Graph, typename Graph::UndirEdgeIt>(w.value);
120  }
121
122  /// \brief Function to count the undirected edges in the graph.
123  ///
124  /// This function counts the undirected edges in the graph.
125  /// The complexity of the function is O(e) but for some
126  /// graph structures it is specialized to run in O(1).
127
128  template <typename Graph>
129  inline int countUndirEdges(const Graph& g) {
130    return _countUndirEdges<Graph>(g);
131  }
132
133
134
135  template <typename Graph, typename DegIt>
136  inline int countNodeDegree(const Graph& _g, const typename Graph::Node& _n) {
137    int num = 0;
138    for (DegIt it(_g, _n); it != INVALID; ++it) {
139      ++num;
140    }
141    return num;
142  }
143
144  /// \brief Function to count the number of the out-edges from node \c n.
145  ///
146  /// This function counts the number of the out-edges from node \c n
147  /// in the graph. 
148  template <typename Graph>
149  inline int countOutEdges(const Graph& _g,  const typename Graph::Node& _n) {
150    return countNodeDegree<Graph, typename Graph::OutEdgeIt>(_g, _n);
151  }
152
153  /// \brief Function to count the number of the in-edges to node \c n.
154  ///
155  /// This function counts the number of the in-edges to node \c n
156  /// in the graph. 
157  template <typename Graph>
158  inline int countInEdges(const Graph& _g,  const typename Graph::Node& _n) {
159    return countNodeDegree<Graph, typename Graph::InEdgeIt>(_g, _n);
160  }
161
162  /// \brief Function to count the number of the in-edges to node \c n.
163  ///
164  /// This function counts the number of the in-edges to node \c n
165  /// in the graph. 
166  template <typename Graph>
167  inline int countIncEdges(const Graph& _g,  const typename Graph::Node& _n) {
168    return countNodeDegree<Graph, typename Graph::IncEdgeIt>(_g, _n);
169  }
170
171
172  template <typename Graph>
173  inline
174  typename enable_if<typename Graph::FindEdgeTag, typename Graph::Edge>::type
175  _findEdge(const Graph &g,
176            typename Graph::Node u, typename Graph::Node v,
177            typename Graph::Edge prev = INVALID) {
178    return g.findEdge(u, v, prev);
179  }
180
181  template <typename Graph>
182  inline typename Graph::Edge
183  _findEdge(Wrap<Graph> w,
184            typename Graph::Node u,
185            typename Graph::Node v,
186            typename Graph::Edge prev = INVALID) {
187    const Graph& g = w.value;
188    if (prev == INVALID) {
189      typename Graph::OutEdgeIt e(g, u);
190      while (e != INVALID && g.target(e) != v) ++e;
191      return e;
192    } else {
193      typename Graph::OutEdgeIt e(g, prev); ++e;
194      while (e != INVALID && g.target(e) != v) ++e;
195      return e;
196    }
197  }
198
199  /// \brief Finds an edge between two nodes of a graph.
200  ///
201  /// Finds an edge from node \c u to node \c v in graph \c g.
202  ///
203  /// If \c prev is \ref INVALID (this is the default value), then
204  /// it finds the first edge from \c u to \c v. Otherwise it looks for
205  /// the next edge from \c u to \c v after \c prev.
206  /// \return The found edge or \ref INVALID if there is no such an edge.
207  ///
208  /// Thus you can iterate through each edge from \c u to \c v as it follows.
209  /// \code
210  /// for(Edge e=findEdge(g,u,v);e!=INVALID;e=findEdge(g,u,v,e)) {
211  ///   ...
212  /// }
213  /// \endcode
214  // /// \todo We may want to use the "GraphBase"
215  // /// interface here...
216  // /// It would not work with the undirected graphs.
217  template <typename Graph>
218  inline typename Graph::Edge findEdge(const Graph &g,
219                                       typename Graph::Node u,
220                                       typename Graph::Node v,
221                                       typename Graph::Edge prev = INVALID) {
222    return _findEdge<Graph>(g, u, v, prev);
223  }
224
225  /// \brief Iterator for iterating on edges connected the same nodes.
226  ///
227  /// Iterator for iterating on edges connected the same nodes. It is
228  /// higher level interface for the findEdge() function. You can
229  /// use it the following way:
230  /// \code
231  /// for (ConEdgeIt<Graph> it(g, src, trg); it != INVALID; ++it) {
232  ///   ...
233  /// }
234  /// \endcode
235  ///
236  /// \author Balazs Dezso
237  template <typename _Graph>
238  class ConEdgeIt : public _Graph::Edge {
239  public:
240
241    typedef _Graph Graph;
242    typedef typename Graph::Edge Parent;
243
244    typedef typename Graph::Edge Edge;
245    typedef typename Graph::Node Node;
246
247    /// \brief Constructor.
248    ///
249    /// Construct a new ConEdgeIt iterating on the edges which
250    /// connects the \c u and \c v node.
251    ConEdgeIt(const Graph& g, Node u, Node v) : graph(g) {
252      Parent::operator=(findEdge(graph, u, v));
253    }
254
255    /// \brief Constructor.
256    ///
257    /// Construct a new ConEdgeIt which continues the iterating from
258    /// the \c e edge.
259    ConEdgeIt(const Graph& g, Edge e) : Parent(e), graph(g) {}
260   
261    /// \brief Increment operator.
262    ///
263    /// It increments the iterator and gives back the next edge.
264    ConEdgeIt& operator++() {
265      Parent::operator=(findEdge(graph, graph.source(*this),
266                                 graph.target(*this), *this));
267      return *this;
268    }
269  private:
270    const Graph& graph;
271  };
272
273  /// \brief Copy a map.
274  ///
275  /// This function copies the \c source map to the \c target map. It uses the
276  /// given iterator to iterate on the data structure and it uses the \c ref
277  /// mapping to convert the source's keys to the target's keys.
278  template <typename Target, typename Source,
279            typename ItemIt, typename Ref>         
280  void copyMap(Target& target, const Source& source,
281               ItemIt it, const Ref& ref) {
282    for (; it != INVALID; ++it) {
283      target[ref[it]] = source[it];
284    }
285  }
286
287  /// \brief Copy the source map to the target map.
288  ///
289  /// Copy the \c source map to the \c target map. It uses the given iterator
290  /// to iterate on the data structure.
291  template <typename Target, typename Source,
292            typename ItemIt>       
293  void copyMap(Target& target, const Source& source, ItemIt it) {
294    for (; it != INVALID; ++it) {
295      target[it] = source[it];
296    }
297  }
298
299
300  /// \brief Class to copy a graph.
301  ///
302  /// Class to copy a graph to an other graph (duplicate a graph). The
303  /// simplest way of using it is through the \c copyGraph() function.
304  template <typename Target, typename Source>
305  class GraphCopy {
306  public:
307    typedef typename Source::Node Node;
308    typedef typename Source::NodeIt NodeIt;
309    typedef typename Source::Edge Edge;
310    typedef typename Source::EdgeIt EdgeIt;
311
312    typedef typename Source::template NodeMap<typename Target::Node>NodeRefMap;
313    typedef typename Source::template EdgeMap<typename Target::Edge>EdgeRefMap;
314
315    /// \brief Constructor for the GraphCopy.
316    ///
317    /// It copies the content of the \c _source graph into the
318    /// \c _target graph. It creates also two references, one beetween
319    /// the two nodeset and one beetween the two edgesets.
320    GraphCopy(Target& _target, const Source& _source)
321      : source(_source), target(_target),
322        nodeRefMap(_source), edgeRefMap(_source) {
323      for (NodeIt it(source); it != INVALID; ++it) {
324        nodeRefMap[it] = target.addNode();
325      }
326      for (EdgeIt it(source); it != INVALID; ++it) {
327        edgeRefMap[it] = target.addEdge(nodeRefMap[source.source(it)],
328                                        nodeRefMap[source.target(it)]);
329      }
330    }
331
332    /// \brief Copies the node references into the given map.
333    ///
334    /// Copies the node references into the given map.
335    template <typename NodeRef>
336    const GraphCopy& nodeRef(NodeRef& map) const {
337      for (NodeIt it(source); it != INVALID; ++it) {
338        map.set(it, nodeRefMap[it]);
339      }
340      return *this;
341    }
342
343    /// \brief Reverse and copies the node references into the given map.
344    ///
345    /// Reverse and copies the node references into the given map.
346    template <typename NodeRef>
347    const GraphCopy& nodeCrossRef(NodeRef& map) const {
348      for (NodeIt it(source); it != INVALID; ++it) {
349        map.set(nodeRefMap[it], it);
350      }
351      return *this;
352    }
353
354    /// \brief Copies the edge references into the given map.
355    ///
356    /// Copies the edge references into the given map.
357    template <typename EdgeRef>
358    const GraphCopy& edgeRef(EdgeRef& map) const {
359      for (EdgeIt it(source); it != INVALID; ++it) {
360        map.set(it, edgeRefMap[it]);
361      }
362      return *this;
363    }
364
365    /// \brief Reverse and copies the edge references into the given map.
366    ///
367    /// Reverse and copies the edge references into the given map.
368    template <typename EdgeRef>
369    const GraphCopy& edgeCrossRef(EdgeRef& map) const {
370      for (EdgeIt it(source); it != INVALID; ++it) {
371        map.set(edgeRefMap[it], it);
372      }
373      return *this;
374    }
375
376    /// \brief Make copy of the given map.
377    ///
378    /// Makes copy of the given map for the newly created graph.
379    /// The new map's key type is the target graph's node type,
380    /// and the copied map's key type is the source graph's node
381    /// type. 
382    template <typename TargetMap, typename SourceMap>
383    const GraphCopy& nodeMap(TargetMap& tMap, const SourceMap& sMap) const {
384      copyMap(tMap, sMap, NodeIt(source), nodeRefMap);
385      return *this;
386    }
387
388    /// \brief Make copy of the given map.
389    ///
390    /// Makes copy of the given map for the newly created graph.
391    /// The new map's key type is the target graph's edge type,
392    /// and the copied map's key type is the source graph's edge
393    /// type. 
394    template <typename TargetMap, typename SourceMap>
395    const GraphCopy& edgeMap(TargetMap& tMap, const SourceMap& sMap) const {
396      copyMap(tMap, sMap, EdgeIt(source), edgeRefMap);
397      return *this;
398    }
399
400    /// \brief Gives back the stored node references.
401    ///
402    /// Gives back the stored node references.
403    const NodeRefMap& nodeRef() const {
404      return nodeRefMap;
405    }
406
407    /// \brief Gives back the stored edge references.
408    ///
409    /// Gives back the stored edge references.
410    const EdgeRefMap& edgeRef() const {
411      return edgeRefMap;
412    }
413
414  private:
415   
416    const Source& source;
417    Target& target;
418
419    NodeRefMap nodeRefMap;
420    EdgeRefMap edgeRefMap;
421  };
422
423  /// \brief Copy a graph to an other graph.
424  ///
425  /// Copy a graph to an other graph.
426  /// The usage of the function:
427  ///
428  /// \code
429  /// copyGraph(trg, src).nodeRef(nr).edgeCrossRef(ecr);
430  /// \endcode
431  ///
432  /// After the copy the \c nr map will contain the mapping from the
433  /// source graph's nodes to the target graph's nodes and the \c ecr will
434  /// contain the mapping from the target graph's edges to the source's
435  /// edges.
436  template <typename Target, typename Source>
437  GraphCopy<Target, Source> copyGraph(Target& target, const Source& source) {
438    return GraphCopy<Target, Source>(target, source);
439  }
440
441  template <typename _Graph, typename _Item>
442  class ItemSetTraits {};
443 
444  template <typename _Graph>
445  class ItemSetTraits<_Graph, typename _Graph::Node> {
446  public:
447   
448    typedef _Graph Graph;
449
450    typedef typename Graph::Node Item;
451    typedef typename Graph::NodeIt ItemIt;
452
453    template <typename _Value>
454    class Map : public Graph::template NodeMap<_Value> {
455    public:
456      typedef typename Graph::template NodeMap<_Value> Parent;
457      typedef typename Parent::Value Value;
458
459      Map(const Graph& _graph) : Parent(_graph) {}
460      Map(const Graph& _graph, const Value& _value)
461        : Parent(_graph, _value) {}
462    };
463
464  };
465
466  template <typename _Graph>
467  class ItemSetTraits<_Graph, typename _Graph::Edge> {
468  public:
469   
470    typedef _Graph Graph;
471
472    typedef typename Graph::Edge Item;
473    typedef typename Graph::EdgeIt ItemIt;
474
475    template <typename _Value>
476    class Map : public Graph::template EdgeMap<_Value> {
477    public:
478      typedef typename Graph::template EdgeMap<_Value> Parent;
479      typedef typename Parent::Value Value;
480
481      Map(const Graph& _graph) : Parent(_graph) {}
482      Map(const Graph& _graph, const Value& _value)
483        : Parent(_graph, _value) {}
484    };
485
486  };
487
488  template <typename _Graph>
489  class ItemSetTraits<_Graph, typename _Graph::UndirEdge> {
490  public:
491   
492    typedef _Graph Graph;
493
494    typedef typename Graph::UndirEdge Item;
495    typedef typename Graph::UndirEdgeIt ItemIt;
496
497    template <typename _Value>
498    class Map : public Graph::template UndirEdgeMap<_Value> {
499    public:
500      typedef typename Graph::template UndirEdgeMap<_Value> Parent;
501      typedef typename Parent::Value Value;
502
503      Map(const Graph& _graph) : Parent(_graph) {}
504      Map(const Graph& _graph, const Value& _value)
505        : Parent(_graph, _value) {}
506    };
507
508  };
509
510  /// @}
511
512  /// \addtogroup graph_maps
513  /// @{
514
515  template <typename Map, typename Enable = void>
516  struct ReferenceMapTraits {
517    typedef typename Map::Value Value;
518    typedef typename Map::Value& Reference;
519    typedef const typename Map::Value& ConstReference;
520    typedef typename Map::Value* Pointer;
521    typedef const typename Map::Value* ConstPointer;
522  };
523
524  template <typename Map>
525  struct ReferenceMapTraits<
526    Map,
527    typename enable_if<typename Map::FullTypeTag, void>::type
528  > {
529    typedef typename Map::Value Value;
530    typedef typename Map::Reference Reference;
531    typedef typename Map::ConstReference ConstReference;
532    typedef typename Map::Pointer Pointer;
533    typedef typename Map::ConstPointer ConstPointer;
534  };
535
536  /// Provides an immutable and unique id for each item in the graph.
537
538  /// The IdMap class provides a unique and immutable id for each item of the
539  /// same type (e.g. node) in the graph. This id is <ul><li>\b unique:
540  /// different items (nodes) get different ids <li>\b immutable: the id of an
541  /// item (node) does not change (even if you delete other nodes).  </ul>
542  /// Through this map you get access (i.e. can read) the inner id values of
543  /// the items stored in the graph. This map can be inverted with its member
544  /// class \c InverseMap.
545  ///
546  template <typename _Graph, typename _Item>
547  class IdMap {
548  public:
549    typedef _Graph Graph;
550    typedef int Value;
551    typedef _Item Item;
552    typedef _Item Key;
553
554    typedef True NeedCopy;
555
556    /// \brief Constructor.
557    ///
558    /// Constructor for creating id map.
559    IdMap(const Graph& _graph) : graph(&_graph) {}
560
561    /// \brief Gives back the \e id of the item.
562    ///
563    /// Gives back the immutable and unique \e id of the map.
564    int operator[](const Item& item) const { return graph->id(item);}
565
566
567  private:
568    const Graph* graph;
569
570  public:
571
572    /// \brief The class represents the inverse of its owner (IdMap).
573    ///
574    /// The class represents the inverse of its owner (IdMap).
575    /// \see inverse()
576    class InverseMap {
577    public:
578
579      typedef True NeedCopy;
580
581      /// \brief Constructor.
582      ///
583      /// Constructor for creating an id-to-item map.
584      InverseMap(const Graph& _graph) : graph(&_graph) {}
585
586      /// \brief Constructor.
587      ///
588      /// Constructor for creating an id-to-item map.
589      InverseMap(const IdMap& idMap) : graph(idMap.graph) {}
590
591      /// \brief Gives back the given item from its id.
592      ///
593      /// Gives back the given item from its id.
594      ///
595      Item operator[](int id) const { return graph->fromId(id, Item());}
596    private:
597      const Graph* graph;
598    };
599
600    /// \brief Gives back the inverse of the map.
601    ///
602    /// Gives back the inverse of the IdMap.
603    InverseMap inverse() const { return InverseMap(*graph);}
604
605  };
606
607 
608  /// \brief General invertable graph-map type.
609
610  /// This type provides simple invertable graph-maps.
611  /// The InvertableMap wraps an arbitrary ReadWriteMap
612  /// and if a key is set to a new value then store it
613  /// in the inverse map.
614  /// \param _Graph The graph type.
615  /// \param _Map The map to extend with invertable functionality.
616  template <
617    typename _Graph,
618    typename _Item,
619    typename _Value,
620    typename _Map
621    = typename ItemSetTraits<_Graph, _Item>::template Map<_Value>::Parent
622  >
623  class InvertableMap : protected _Map {
624
625  public:
626 
627    typedef _Map Map;
628    typedef _Graph Graph;
629
630    /// The key type of InvertableMap (Node, Edge, UndirEdge).
631    typedef typename _Map::Key Key;
632    /// The value type of the InvertableMap.
633    typedef typename _Map::Value Value;
634
635    /// \brief Constructor.
636    ///
637    /// Construct a new InvertableMap for the graph.
638    ///
639    InvertableMap(const Graph& graph) : Map(graph) {}
640   
641    /// \brief The setter function of the map.
642    ///
643    /// Sets the mapped value.
644    void set(const Key& key, const Value& val) {
645      Value oldval = Map::operator[](key);
646      typename Container::iterator it = invMap.find(oldval);
647      if (it != invMap.end() && it->second == key) {
648        invMap.erase(it);
649      }     
650      invMap.insert(make_pair(val, key));
651      Map::set(key, val);
652    }
653
654    /// \brief The getter function of the map.
655    ///
656    /// It gives back the value associated with the key.
657    const Value operator[](const Key& key) const {
658      return Map::operator[](key);
659    }
660
661  protected:
662
663    /// \brief Add a new key to the map.
664    ///
665    /// Add a new key to the map. It is called by the
666    /// \c AlterationNotifier.
667    virtual void add(const Key& key) {
668      Map::add(key);
669    }
670
671    /// \brief Erase the key from the map.
672    ///
673    /// Erase the key to the map. It is called by the
674    /// \c AlterationNotifier.
675    virtual void erase(const Key& key) {
676      Value val = Map::operator[](key);
677      typename Container::iterator it = invMap.find(val);
678      if (it != invMap.end() && it->second == key) {
679        invMap.erase(it);
680      }
681      Map::erase(key);
682    }
683
684    /// \brief Clear the keys from the map and inverse map.
685    ///
686    /// Clear the keys from the map and inverse map. It is called by the
687    /// \c AlterationNotifier.
688    virtual void clear() {
689      invMap.clear();
690      Map::clear();
691    }
692
693  private:
694   
695    typedef std::map<Value, Key> Container;
696    Container invMap;   
697
698  public:
699
700    /// \brief The inverse map type.
701    ///
702    /// The inverse of this map. The subscript operator of the map
703    /// gives back always the item what was last assigned to the value.
704    class InverseMap {
705    public:
706      /// \brief Constructor of the InverseMap.
707      ///
708      /// Constructor of the InverseMap.
709      InverseMap(const InvertableMap& _inverted) : inverted(_inverted) {}
710
711      /// The value type of the InverseMap.
712      typedef typename InvertableMap::Key Value;
713      /// The key type of the InverseMap.
714      typedef typename InvertableMap::Value Key;
715
716      /// \brief Subscript operator.
717      ///
718      /// Subscript operator. It gives back always the item
719      /// what was last assigned to the value.
720      Value operator[](const Key& key) const {
721        typename Container::const_iterator it = inverted.invMap.find(key);
722        return it->second;
723      }
724     
725    private:
726      const InvertableMap& inverted;
727    };
728
729    /// \brief It gives back the just readeable inverse map.
730    ///
731    /// It gives back the just readeable inverse map.
732    InverseMap inverse() const {
733      return InverseMap(*this);
734    }
735
736
737   
738  };
739
740  /// \brief Provides a mutable, continuous and unique descriptor for each
741  /// item in the graph.
742  ///
743  /// The DescriptorMap class provides a unique and continuous (but mutable)
744  /// descriptor (id) for each item of the same type (e.g. node) in the
745  /// graph. This id is <ul><li>\b unique: different items (nodes) get
746  /// different ids <li>\b continuous: the range of the ids is the set of
747  /// integers between 0 and \c n-1, where \c n is the number of the items of
748  /// this type (e.g. nodes) (so the id of a node can change if you delete an
749  /// other node, i.e. this id is mutable).  </ul> This map can be inverted
750  /// with its member class \c InverseMap.
751  ///
752  /// \param _Graph The graph class the \c DescriptorMap belongs to.
753  /// \param _Item The Item is the Key of the Map. It may be Node, Edge or
754  /// UndirEdge.
755  /// \param _Map A ReadWriteMap mapping from the item type to integer.
756  template <
757    typename _Graph,   
758    typename _Item,
759    typename _Map
760    = typename ItemSetTraits<_Graph, _Item>::template Map<int>::Parent
761  >
762  class DescriptorMap : protected _Map {
763
764    typedef _Item Item;
765    typedef _Map Map;
766
767  public:
768    /// The graph class of DescriptorMap.
769    typedef _Graph Graph;
770
771    /// The key type of DescriptorMap (Node, Edge, UndirEdge).
772    typedef typename _Map::Key Key;
773    /// The value type of DescriptorMap.
774    typedef typename _Map::Value Value;
775
776    /// \brief Constructor.
777    ///
778    /// Constructor for descriptor map.
779    DescriptorMap(const Graph& _graph) : Map(_graph) {
780      build();
781    }
782
783  protected:
784
785    /// \brief Add a new key to the map.
786    ///
787    /// Add a new key to the map. It is called by the
788    /// \c AlterationNotifier.
789    virtual void add(const Item& item) {
790      Map::add(item);
791      Map::set(item, invMap.size());
792      invMap.push_back(item);
793    }
794
795    /// \brief Erase the key from the map.
796    ///
797    /// Erase the key to the map. It is called by the
798    /// \c AlterationNotifier.
799    virtual void erase(const Item& item) {
800      Map::set(invMap.back(), Map::operator[](item));
801      invMap[Map::operator[](item)] = invMap.back();
802      invMap.pop_back();
803      Map::erase(item);
804    }
805
806    /// \brief Build the unique map.
807    ///
808    /// Build the unique map. It is called by the
809    /// \c AlterationNotifier.
810    virtual void build() {
811      Map::build();
812      Item it;
813      const typename Map::Graph* graph = Map::getGraph();
814      for (graph->first(it); it != INVALID; graph->next(it)) {
815        Map::set(it, invMap.size());
816        invMap.push_back(it);   
817      }     
818    }
819   
820    /// \brief Clear the keys from the map.
821    ///
822    /// Clear the keys from the map. It is called by the
823    /// \c AlterationNotifier.
824    virtual void clear() {
825      invMap.clear();
826      Map::clear();
827    }
828
829  public:
830
831    /// \brief Swaps the position of the two items in the map.
832    ///
833    /// Swaps the position of the two items in the map.
834    void swap(const Item& p, const Item& q) {
835      int pi = Map::operator[](p);
836      int qi = Map::operator[](q);
837      Map::set(p, qi);
838      invMap[qi] = p;
839      Map::set(q, pi);
840      invMap[pi] = q;
841    }
842
843    /// \brief Gives back the \e descriptor of the item.
844    ///
845    /// Gives back the mutable and unique \e descriptor of the map.
846    int operator[](const Item& item) const {
847      return Map::operator[](item);
848    }
849   
850  private:
851
852    typedef std::vector<Item> Container;
853    Container invMap;
854
855  public:
856    /// \brief The inverse map type of DescriptorMap.
857    ///
858    /// The inverse map type of DescriptorMap.
859    class InverseMap {
860    public:
861      /// \brief Constructor of the InverseMap.
862      ///
863      /// Constructor of the InverseMap.
864      InverseMap(const DescriptorMap& _inverted)
865        : inverted(_inverted) {}
866
867
868      /// The value type of the InverseMap.
869      typedef typename DescriptorMap::Key Value;
870      /// The key type of the InverseMap.
871      typedef typename DescriptorMap::Value Key;
872
873      /// \brief Subscript operator.
874      ///
875      /// Subscript operator. It gives back the item
876      /// that the descriptor belongs to currently.
877      Value operator[](const Key& key) const {
878        return inverted.invMap[key];
879      }
880
881      /// \brief Size of the map.
882      ///
883      /// Returns the size of the map.
884      int size() const {
885        return inverted.invMap.size();
886      }
887     
888    private:
889      const DescriptorMap& inverted;
890    };
891
892    /// \brief Gives back the inverse of the map.
893    ///
894    /// Gives back the inverse of the map.
895    const InverseMap inverse() const {
896      return InverseMap(*this);
897    }
898  };
899
900  /// \brief Returns the source of the given edge.
901  ///
902  /// The SourceMap gives back the source Node of the given edge.
903  /// \author Balazs Dezso
904  template <typename Graph>
905  class SourceMap {
906  public:
907
908    typedef True NeedCopy;
909
910    typedef typename Graph::Node Value;
911    typedef typename Graph::Edge Key;
912
913    /// \brief Constructor
914    ///
915    /// Constructor
916    /// \param _graph The graph that the map belongs to.
917    SourceMap(const Graph& _graph) : graph(_graph) {}
918
919    /// \brief The subscript operator.
920    ///
921    /// The subscript operator.
922    /// \param edge The edge
923    /// \return The source of the edge
924    Value operator[](const Key& edge) const {
925      return graph.source(edge);
926    }
927
928  private:
929    const Graph& graph;
930  };
931
932  /// \brief Returns a \ref SourceMap class
933  ///
934  /// This function just returns an \ref SourceMap class.
935  /// \relates SourceMap
936  template <typename Graph>
937  inline SourceMap<Graph> sourceMap(const Graph& graph) {
938    return SourceMap<Graph>(graph);
939  }
940
941  /// \brief Returns the target of the given edge.
942  ///
943  /// The TargetMap gives back the target Node of the given edge.
944  /// \author Balazs Dezso
945  template <typename Graph>
946  class TargetMap {
947  public:
948
949    typedef True NeedCopy;
950
951    typedef typename Graph::Node Value;
952    typedef typename Graph::Edge Key;
953
954    /// \brief Constructor
955    ///
956    /// Constructor
957    /// \param _graph The graph that the map belongs to.
958    TargetMap(const Graph& _graph) : graph(_graph) {}
959
960    /// \brief The subscript operator.
961    ///
962    /// The subscript operator.
963    /// \param e The edge
964    /// \return The target of the edge
965    Value operator[](const Key& e) const {
966      return graph.target(e);
967    }
968
969  private:
970    const Graph& graph;
971  };
972
973  /// \brief Returns a \ref TargetMap class
974  ///
975  /// This function just returns a \ref TargetMap class.
976  /// \relates TargetMap
977  template <typename Graph>
978  inline TargetMap<Graph> targetMap(const Graph& graph) {
979    return TargetMap<Graph>(graph);
980  }
981
982  /// \brief Returns the "forward" directed edge view of an undirected edge.
983  ///
984  /// Returns the "forward" directed edge view of an undirected edge.
985  /// \author Balazs Dezso
986  template <typename Graph>
987  class ForwardMap {
988  public:
989
990    typedef True NeedCopy;
991
992    typedef typename Graph::Edge Value;
993    typedef typename Graph::UndirEdge Key;
994
995    /// \brief Constructor
996    ///
997    /// Constructor
998    /// \param _graph The graph that the map belongs to.
999    ForwardMap(const Graph& _graph) : graph(_graph) {}
1000
1001    /// \brief The subscript operator.
1002    ///
1003    /// The subscript operator.
1004    /// \param key An undirected edge
1005    /// \return The "forward" directed edge view of undirected edge
1006    Value operator[](const Key& key) const {
1007      return graph.direct(key, true);
1008    }
1009
1010  private:
1011    const Graph& graph;
1012  };
1013
1014  /// \brief Returns a \ref ForwardMap class
1015  ///
1016  /// This function just returns an \ref ForwardMap class.
1017  /// \relates ForwardMap
1018  template <typename Graph>
1019  inline ForwardMap<Graph> forwardMap(const Graph& graph) {
1020    return ForwardMap<Graph>(graph);
1021  }
1022
1023  /// \brief Returns the "backward" directed edge view of an undirected edge.
1024  ///
1025  /// Returns the "backward" directed edge view of an undirected edge.
1026  /// \author Balazs Dezso
1027  template <typename Graph>
1028  class BackwardMap {
1029  public:
1030    typedef True NeedCopy;
1031
1032    typedef typename Graph::Edge Value;
1033    typedef typename Graph::UndirEdge Key;
1034
1035    /// \brief Constructor
1036    ///
1037    /// Constructor
1038    /// \param _graph The graph that the map belongs to.
1039    BackwardMap(const Graph& _graph) : graph(_graph) {}
1040
1041    /// \brief The subscript operator.
1042    ///
1043    /// The subscript operator.
1044    /// \param key An undirected edge
1045    /// \return The "backward" directed edge view of undirected edge
1046    Value operator[](const Key& key) const {
1047      return graph.direct(key, false);
1048    }
1049
1050  private:
1051    const Graph& graph;
1052  };
1053
1054  /// \brief Returns a \ref BackwardMap class
1055
1056  /// This function just returns a \ref BackwardMap class.
1057  /// \relates BackwardMap
1058  template <typename Graph>
1059  inline BackwardMap<Graph> backwardMap(const Graph& graph) {
1060    return BackwardMap<Graph>(graph);
1061  }
1062
1063  template <typename _Graph>
1064  class DegMapBase {
1065  public:
1066   
1067    typedef _Graph Graph;
1068
1069  protected:
1070
1071    typedef typename Graph::template NodeMap<int> IntNodeMap;
1072   
1073  };
1074
1075  /// \brief Map of the node in-degrees.
1076  ///
1077  /// This map returns the in-degree of a node. Once it is constructed,
1078  /// the degrees are stored in a standard NodeMap, so each query is done
1079  /// in constant time. On the other hand, the values are updated automatically
1080  /// whenever the graph changes.
1081  ///
1082  /// \warning Besides addNode() and addEdge(), a graph structure may provide
1083  /// alternative ways to mogify the graph. The correct behavior of InDegMap
1084  /// is not guarantied if these additional featureas are used. For example
1085  /// the funstions \ref ListGraph::changeSource() "changeSource()",
1086  /// \ref ListGraph::changeTarget() "changeTarget()" and
1087  /// \ref ListGraph::reverseEdge() "reverseEdge()"
1088  /// of \ref ListGraph will \e not update the degree values correctly.
1089  ///
1090  /// \sa OutDegMap
1091
1092  template <typename _Graph>
1093  class InDegMap 
1094    : protected AlterationNotifier<typename _Graph::Edge>::ObserverBase {
1095
1096  public:
1097   
1098    typedef _Graph Graph;
1099    typedef int Value;
1100    typedef typename Graph::Node Key;
1101
1102  private:
1103
1104    class AutoNodeMap : public Graph::template NodeMap<int> {
1105    public:
1106
1107      typedef typename Graph::template NodeMap<int> Parent;
1108
1109      typedef typename Parent::Key Key;
1110      typedef typename Parent::Value Value;
1111     
1112      AutoNodeMap(const Graph& graph) : Parent(graph, 0) {}
1113     
1114      void add(const Key& key) {
1115        Parent::add(key);
1116        Parent::set(key, 0);
1117      }
1118    };
1119
1120  public:
1121
1122    /// \brief Constructor.
1123    ///
1124    /// Constructor for creating in-degree map.
1125    InDegMap(const Graph& _graph) : graph(_graph), deg(_graph) {
1126      AlterationNotifier<typename _Graph::Edge>
1127        ::ObserverBase::attach(graph.getNotifier(typename _Graph::Edge()));
1128     
1129      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1130        deg[it] = countInEdges(graph, it);
1131      }
1132    }
1133
1134    virtual ~InDegMap() {
1135      AlterationNotifier<typename _Graph::Edge>::
1136        ObserverBase::detach();
1137    }
1138   
1139    /// Gives back the in-degree of a Node.
1140    int operator[](const Key& key) const {
1141      return deg[key];
1142    }
1143
1144  protected:
1145   
1146    typedef typename Graph::Edge Edge;
1147
1148    virtual void add(const Edge& edge) {
1149      ++deg[graph.target(edge)];
1150    }
1151
1152    virtual void erase(const Edge& edge) {
1153      --deg[graph.target(edge)];
1154    }
1155
1156
1157    virtual void build() {
1158      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1159        deg[it] = countInEdges(graph, it);
1160      }     
1161    }
1162
1163    virtual void clear() {
1164      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1165        deg[it] = 0;
1166      }
1167    }
1168  private:
1169   
1170    const _Graph& graph;
1171    AutoNodeMap deg;
1172  };
1173
1174  /// \brief Map of the node out-degrees.
1175  ///
1176  /// This map returns the out-degree of a node. Once it is constructed,
1177  /// the degrees are stored in a standard NodeMap, so each query is done
1178  /// in constant time. On the other hand, the values are updated automatically
1179  /// whenever the graph changes.
1180  ///
1181  /// \warning Besides addNode() and addEdge(), a graph structure may provide
1182  /// alternative ways to mogify the graph. The correct behavior of OutDegMap
1183  /// is not guarantied if these additional featureas are used. For example
1184  /// the funstions \ref ListGraph::changeSource() "changeSource()",
1185  /// \ref ListGraph::changeTarget() "changeTarget()" and
1186  /// \ref ListGraph::reverseEdge() "reverseEdge()"
1187  /// of \ref ListGraph will \e not update the degree values correctly.
1188  ///
1189  /// \sa InDegMap
1190
1191  template <typename _Graph>
1192  class OutDegMap 
1193    : protected AlterationNotifier<typename _Graph::Edge>::ObserverBase {
1194
1195  public:
1196   
1197    typedef _Graph Graph;
1198    typedef int Value;
1199    typedef typename Graph::Node Key;
1200
1201  private:
1202
1203    class AutoNodeMap : public Graph::template NodeMap<int> {
1204    public:
1205
1206      typedef typename Graph::template NodeMap<int> Parent;
1207
1208      typedef typename Parent::Key Key;
1209      typedef typename Parent::Value Value;
1210     
1211      AutoNodeMap(const Graph& graph) : Parent(graph, 0) {}
1212     
1213      void add(const Key& key) {
1214        Parent::add(key);
1215        Parent::set(key, 0);
1216      }
1217    };
1218
1219  public:
1220
1221    /// \brief Constructor.
1222    ///
1223    /// Constructor for creating out-degree map.
1224    OutDegMap(const Graph& _graph) : graph(_graph), deg(_graph) {
1225      AlterationNotifier<typename _Graph::Edge>
1226        ::ObserverBase::attach(graph.getNotifier(typename _Graph::Edge()));
1227     
1228      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1229        deg[it] = countOutEdges(graph, it);
1230      }
1231    }
1232
1233    virtual ~OutDegMap() {
1234      AlterationNotifier<typename _Graph::Edge>::
1235        ObserverBase::detach();
1236    }
1237   
1238    /// Gives back the in-degree of a Node.
1239    int operator[](const Key& key) const {
1240      return deg[key];
1241    }
1242
1243  protected:
1244   
1245    typedef typename Graph::Edge Edge;
1246
1247    virtual void add(const Edge& edge) {
1248      ++deg[graph.source(edge)];
1249    }
1250
1251    virtual void erase(const Edge& edge) {
1252      --deg[graph.source(edge)];
1253    }
1254
1255
1256    virtual void build() {
1257      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1258        deg[it] = countOutEdges(graph, it);
1259      }     
1260    }
1261
1262    virtual void clear() {
1263      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1264        deg[it] = 0;
1265      }
1266    }
1267  private:
1268   
1269    const _Graph& graph;
1270    AutoNodeMap deg;
1271  };
1272
1273  /// @}
1274
1275} //END OF NAMESPACE LEMON
1276
1277#endif
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