COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/graph_utils.h @ 1627:3fd1ba6e9872

Last change on this file since 1627:3fd1ba6e9872 was 1627:3fd1ba6e9872, checked in by Balazs Dezso, 14 years ago

Some modification on the undirected graph interface.
Doc improvments

File size: 33.9 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
163  template <typename Graph>
164  inline
165  typename enable_if<typename Graph::FindEdgeTag, typename Graph::Edge>::type
166  _findEdge(const Graph &g,
167            typename Graph::Node u, typename Graph::Node v,
168            typename Graph::Edge prev = INVALID) {
169    return g.findEdge(u, v, prev);
170  }
171
172  template <typename Graph>
173  inline typename Graph::Edge
174  _findEdge(Wrap<Graph> w,
175            typename Graph::Node u,
176            typename Graph::Node v,
177            typename Graph::Edge prev = INVALID) {
178    const Graph& g = w.value;
179    if (prev == INVALID) {
180      typename Graph::OutEdgeIt e(g, u);
181      while (e != INVALID && g.target(e) != v) ++e;
182      return e;
183    } else {
184      typename Graph::OutEdgeIt e(g, prev); ++e;
185      while (e != INVALID && g.target(e) != v) ++e;
186      return e;
187    }
188  }
189
190  /// \brief Finds an edge between two nodes of a graph.
191  ///
192  /// Finds an edge from node \c u to node \c v in graph \c g.
193  ///
194  /// If \c prev is \ref INVALID (this is the default value), then
195  /// it finds the first edge from \c u to \c v. Otherwise it looks for
196  /// the next edge from \c u to \c v after \c prev.
197  /// \return The found edge or \ref INVALID if there is no such an edge.
198  ///
199  /// Thus you can iterate through each edge from \c u to \c v as it follows.
200  /// \code
201  /// for(Edge e=findEdge(g,u,v);e!=INVALID;e=findEdge(g,u,v,e)) {
202  ///   ...
203  /// }
204  /// \endcode
205  // /// \todo We may want to use the "GraphBase"
206  // /// interface here...
207  // /// It would not work with the undirected graphs.
208  template <typename Graph>
209  inline typename Graph::Edge findEdge(const Graph &g,
210                                       typename Graph::Node u,
211                                       typename Graph::Node v,
212                                       typename Graph::Edge prev = INVALID) {
213    return _findEdge<Graph>(g, u, v, prev);
214  }
215
216  /// \brief Iterator for iterating on edges connected the same nodes.
217  ///
218  /// Iterator for iterating on edges connected the same nodes. It is
219  /// higher level interface for the findEdge() function. You can
220  /// use it the following way:
221  /// \code
222  /// for (ConEdgeIt<Graph> it(g, src, trg); it != INVALID; ++it) {
223  ///   ...
224  /// }
225  /// \endcode
226  ///
227  /// \author Balazs Dezso
228  template <typename _Graph>
229  class ConEdgeIt : public _Graph::Edge {
230  public:
231
232    typedef _Graph Graph;
233    typedef typename Graph::Edge Parent;
234
235    typedef typename Graph::Edge Edge;
236    typedef typename Graph::Node Node;
237
238    /// \brief Constructor.
239    ///
240    /// Construct a new ConEdgeIt iterating on the edges which
241    /// connects the \c u and \c v node.
242    ConEdgeIt(const Graph& g, Node u, Node v) : graph(g) {
243      Parent::operator=(findEdge(graph, u, v));
244    }
245
246    /// \brief Constructor.
247    ///
248    /// Construct a new ConEdgeIt which continues the iterating from
249    /// the \c e edge.
250    ConEdgeIt(const Graph& g, Edge e) : Parent(e), graph(g) {}
251   
252    /// \brief Increment operator.
253    ///
254    /// It increments the iterator and gives back the next edge.
255    ConEdgeIt& operator++() {
256      Parent::operator=(findEdge(graph, graph.source(*this),
257                                 graph.target(*this), *this));
258      return *this;
259    }
260  private:
261    const Graph& graph;
262  };
263
264  /// \brief Copy a map.
265  ///
266  /// This function copies the \c source map to the \c target map. It uses the
267  /// given iterator to iterate on the data structure and it uses the \c ref
268  /// mapping to convert the source's keys to the target's keys.
269  template <typename Target, typename Source,
270            typename ItemIt, typename Ref>         
271  void copyMap(Target& target, const Source& source,
272               ItemIt it, const Ref& ref) {
273    for (; it != INVALID; ++it) {
274      target[ref[it]] = source[it];
275    }
276  }
277
278  /// \brief Copy the source map to the target map.
279  ///
280  /// Copy the \c source map to the \c target map. It uses the given iterator
281  /// to iterate on the data structure.
282  template <typename Target, typename Source,
283            typename ItemIt>       
284  void copyMap(Target& target, const Source& source, ItemIt it) {
285    for (; it != INVALID; ++it) {
286      target[it] = source[it];
287    }
288  }
289
290
291  /// \brief Class to copy a graph.
292  ///
293  /// Class to copy a graph to an other graph (duplicate a graph). The
294  /// simplest way of using it is through the \c copyGraph() function.
295  template <typename Target, typename Source>
296  class GraphCopy {
297  public:
298    typedef typename Source::Node Node;
299    typedef typename Source::NodeIt NodeIt;
300    typedef typename Source::Edge Edge;
301    typedef typename Source::EdgeIt EdgeIt;
302
303    typedef typename Source::template NodeMap<typename Target::Node>NodeRefMap;
304    typedef typename Source::template EdgeMap<typename Target::Edge>EdgeRefMap;
305
306    /// \brief Constructor for the GraphCopy.
307    ///
308    /// It copies the content of the \c _source graph into the
309    /// \c _target graph. It creates also two references, one beetween
310    /// the two nodeset and one beetween the two edgesets.
311    GraphCopy(Target& _target, const Source& _source)
312      : source(_source), target(_target),
313        nodeRefMap(_source), edgeRefMap(_source) {
314      for (NodeIt it(source); it != INVALID; ++it) {
315        nodeRefMap[it] = target.addNode();
316      }
317      for (EdgeIt it(source); it != INVALID; ++it) {
318        edgeRefMap[it] = target.addEdge(nodeRefMap[source.source(it)],
319                                        nodeRefMap[source.target(it)]);
320      }
321    }
322
323    /// \brief Copies the node references into the given map.
324    ///
325    /// Copies the node references into the given map.
326    template <typename NodeRef>
327    const GraphCopy& nodeRef(NodeRef& map) const {
328      for (NodeIt it(source); it != INVALID; ++it) {
329        map.set(it, nodeRefMap[it]);
330      }
331      return *this;
332    }
333
334    /// \brief Reverse and copies the node references into the given map.
335    ///
336    /// Reverse and copies the node references into the given map.
337    template <typename NodeRef>
338    const GraphCopy& nodeCrossRef(NodeRef& map) const {
339      for (NodeIt it(source); it != INVALID; ++it) {
340        map.set(nodeRefMap[it], it);
341      }
342      return *this;
343    }
344
345    /// \brief Copies the edge references into the given map.
346    ///
347    /// Copies the edge references into the given map.
348    template <typename EdgeRef>
349    const GraphCopy& edgeRef(EdgeRef& map) const {
350      for (EdgeIt it(source); it != INVALID; ++it) {
351        map.set(it, edgeRefMap[it]);
352      }
353      return *this;
354    }
355
356    /// \brief Reverse and copies the edge references into the given map.
357    ///
358    /// Reverse and copies the edge references into the given map.
359    template <typename EdgeRef>
360    const GraphCopy& edgeCrossRef(EdgeRef& map) const {
361      for (EdgeIt it(source); it != INVALID; ++it) {
362        map.set(edgeRefMap[it], it);
363      }
364      return *this;
365    }
366
367    /// \brief Make copy of the given map.
368    ///
369    /// Makes copy of the given map for the newly created graph.
370    /// The new map's key type is the target graph's node type,
371    /// and the copied map's key type is the source graph's node
372    /// type. 
373    template <typename TargetMap, typename SourceMap>
374    const GraphCopy& nodeMap(TargetMap& tMap, const SourceMap& sMap) const {
375      copyMap(tMap, sMap, NodeIt(source), nodeRefMap);
376      return *this;
377    }
378
379    /// \brief Make copy of the given map.
380    ///
381    /// Makes copy of the given map for the newly created graph.
382    /// The new map's key type is the target graph's edge type,
383    /// and the copied map's key type is the source graph's edge
384    /// type. 
385    template <typename TargetMap, typename SourceMap>
386    const GraphCopy& edgeMap(TargetMap& tMap, const SourceMap& sMap) const {
387      copyMap(tMap, sMap, EdgeIt(source), edgeRefMap);
388      return *this;
389    }
390
391    /// \brief Gives back the stored node references.
392    ///
393    /// Gives back the stored node references.
394    const NodeRefMap& nodeRef() const {
395      return nodeRefMap;
396    }
397
398    /// \brief Gives back the stored edge references.
399    ///
400    /// Gives back the stored edge references.
401    const EdgeRefMap& edgeRef() const {
402      return edgeRefMap;
403    }
404
405  private:
406   
407    const Source& source;
408    Target& target;
409
410    NodeRefMap nodeRefMap;
411    EdgeRefMap edgeRefMap;
412  };
413
414  /// \brief Copy a graph to an other graph.
415  ///
416  /// Copy a graph to an other graph.
417  /// The usage of the function:
418  ///
419  /// \code
420  /// copyGraph(trg, src).nodeRef(nr).edgeCrossRef(ecr);
421  /// \endcode
422  ///
423  /// After the copy the \c nr map will contain the mapping from the
424  /// source graph's nodes to the target graph's nodes and the \c ecr will
425  /// contain the mapping from the target graph's edges to the source's
426  /// edges.
427  template <typename Target, typename Source>
428  GraphCopy<Target, Source> copyGraph(Target& target, const Source& source) {
429    return GraphCopy<Target, Source>(target, source);
430  }
431
432  template <typename _Graph, typename _Item>
433  class ItemSetTraits {};
434 
435  template <typename _Graph>
436  class ItemSetTraits<_Graph, typename _Graph::Node> {
437  public:
438   
439    typedef _Graph Graph;
440
441    typedef typename Graph::Node Item;
442    typedef typename Graph::NodeIt ItemIt;
443
444    template <typename _Value>
445    class Map : public Graph::template NodeMap<_Value> {
446    public:
447      typedef typename Graph::template NodeMap<_Value> Parent;
448      typedef typename Parent::Value Value;
449
450      Map(const Graph& _graph) : Parent(_graph) {}
451      Map(const Graph& _graph, const Value& _value)
452        : Parent(_graph, _value) {}
453    };
454
455  };
456
457  template <typename _Graph>
458  class ItemSetTraits<_Graph, typename _Graph::Edge> {
459  public:
460   
461    typedef _Graph Graph;
462
463    typedef typename Graph::Edge Item;
464    typedef typename Graph::EdgeIt ItemIt;
465
466    template <typename _Value>
467    class Map : public Graph::template EdgeMap<_Value> {
468    public:
469      typedef typename Graph::template EdgeMap<_Value> Parent;
470      typedef typename Parent::Value Value;
471
472      Map(const Graph& _graph) : Parent(_graph) {}
473      Map(const Graph& _graph, const Value& _value)
474        : Parent(_graph, _value) {}
475    };
476
477  };
478
479  template <typename _Graph>
480  class ItemSetTraits<_Graph, typename _Graph::UndirEdge> {
481  public:
482   
483    typedef _Graph Graph;
484
485    typedef typename Graph::UndirEdge Item;
486    typedef typename Graph::UndirEdgeIt ItemIt;
487
488    template <typename _Value>
489    class Map : public Graph::template UndirEdgeMap<_Value> {
490    public:
491      typedef typename Graph::template UndirEdgeMap<_Value> Parent;
492      typedef typename Parent::Value Value;
493
494      Map(const Graph& _graph) : Parent(_graph) {}
495      Map(const Graph& _graph, const Value& _value)
496        : Parent(_graph, _value) {}
497    };
498
499  };
500
501  /// @}
502
503  /// \addtogroup graph_maps
504  /// @{
505
506  template <typename Map, typename Enable = void>
507  struct ReferenceMapTraits {
508    typedef typename Map::Value Value;
509    typedef typename Map::Value& Reference;
510    typedef const typename Map::Value& ConstReference;
511    typedef typename Map::Value* Pointer;
512    typedef const typename Map::Value* ConstPointer;
513  };
514
515  template <typename Map>
516  struct ReferenceMapTraits<
517    Map,
518    typename enable_if<typename Map::FullTypeTag, void>::type
519  > {
520    typedef typename Map::Value Value;
521    typedef typename Map::Reference Reference;
522    typedef typename Map::ConstReference ConstReference;
523    typedef typename Map::Pointer Pointer;
524    typedef typename Map::ConstPointer ConstPointer;
525  };
526
527  /// Provides an immutable and unique id for each item in the graph.
528
529  /// The IdMap class provides a unique and immutable id for each item of the
530  /// same type (e.g. node) in the graph. This id is <ul><li>\b unique:
531  /// different items (nodes) get different ids <li>\b immutable: the id of an
532  /// item (node) does not change (even if you delete other nodes).  </ul>
533  /// Through this map you get access (i.e. can read) the inner id values of
534  /// the items stored in the graph. This map can be inverted with its member
535  /// class \c InverseMap.
536  ///
537  template <typename _Graph, typename _Item>
538  class IdMap {
539  public:
540    typedef _Graph Graph;
541    typedef int Value;
542    typedef _Item Item;
543    typedef _Item Key;
544
545    typedef True NeedCopy;
546
547    /// \brief Constructor.
548    ///
549    /// Constructor for creating id map.
550    IdMap(const Graph& _graph) : graph(&_graph) {}
551
552    /// \brief Gives back the \e id of the item.
553    ///
554    /// Gives back the immutable and unique \e id of the map.
555    int operator[](const Item& item) const { return graph->id(item);}
556
557
558  private:
559    const Graph* graph;
560
561  public:
562
563    /// \brief The class represents the inverse of its owner (IdMap).
564    ///
565    /// The class represents the inverse of its owner (IdMap).
566    /// \see inverse()
567    class InverseMap {
568    public:
569
570      typedef True NeedCopy;
571
572      /// \brief Constructor.
573      ///
574      /// Constructor for creating an id-to-item map.
575      InverseMap(const Graph& _graph) : graph(&_graph) {}
576
577      /// \brief Constructor.
578      ///
579      /// Constructor for creating an id-to-item map.
580      InverseMap(const IdMap& idMap) : graph(idMap.graph) {}
581
582      /// \brief Gives back the given item from its id.
583      ///
584      /// Gives back the given item from its id.
585      ///
586      Item operator[](int id) const { return graph->fromId(id, Item());}
587    private:
588      const Graph* graph;
589    };
590
591    /// \brief Gives back the inverse of the map.
592    ///
593    /// Gives back the inverse of the IdMap.
594    InverseMap inverse() const { return InverseMap(*graph);}
595
596  };
597
598 
599  /// \brief General invertable graph-map type.
600
601  /// This type provides simple invertable graph-maps.
602  /// The InvertableMap wraps an arbitrary ReadWriteMap
603  /// and if a key is set to a new value then store it
604  /// in the inverse map.
605  /// \param _Graph The graph type.
606  /// \param _Map The map to extend with invertable functionality.
607  template <
608    typename _Graph,
609    typename _Item,
610    typename _Value,
611    typename _Map
612    = typename ItemSetTraits<_Graph, _Item>::template Map<_Value>::Parent
613  >
614  class InvertableMap : protected _Map {
615
616  public:
617 
618    typedef _Map Map;
619    typedef _Graph Graph;
620
621    /// The key type of InvertableMap (Node, Edge, UndirEdge).
622    typedef typename _Map::Key Key;
623    /// The value type of the InvertableMap.
624    typedef typename _Map::Value Value;
625
626    /// \brief Constructor.
627    ///
628    /// Construct a new InvertableMap for the graph.
629    ///
630    InvertableMap(const Graph& graph) : Map(graph) {}
631   
632    /// \brief The setter function of the map.
633    ///
634    /// Sets the mapped value.
635    void set(const Key& key, const Value& val) {
636      Value oldval = Map::operator[](key);
637      typename Container::iterator it = invMap.find(oldval);
638      if (it != invMap.end() && it->second == key) {
639        invMap.erase(it);
640      }     
641      invMap.insert(make_pair(val, key));
642      Map::set(key, val);
643    }
644
645    /// \brief The getter function of the map.
646    ///
647    /// It gives back the value associated with the key.
648    const Value operator[](const Key& key) const {
649      return Map::operator[](key);
650    }
651
652  protected:
653
654    /// \brief Add a new key to the map.
655    ///
656    /// Add a new key to the map. It is called by the
657    /// \c AlterationNotifier.
658    virtual void add(const Key& key) {
659      Map::add(key);
660    }
661
662    /// \brief Erase the key from the map.
663    ///
664    /// Erase the key to the map. It is called by the
665    /// \c AlterationNotifier.
666    virtual void erase(const Key& key) {
667      Value val = Map::operator[](key);
668      typename Container::iterator it = invMap.find(val);
669      if (it != invMap.end() && it->second == key) {
670        invMap.erase(it);
671      }
672      Map::erase(key);
673    }
674
675    /// \brief Clear the keys from the map and inverse map.
676    ///
677    /// Clear the keys from the map and inverse map. It is called by the
678    /// \c AlterationNotifier.
679    virtual void clear() {
680      invMap.clear();
681      Map::clear();
682    }
683
684  private:
685   
686    typedef std::map<Value, Key> Container;
687    Container invMap;   
688
689  public:
690
691    /// \brief The inverse map type.
692    ///
693    /// The inverse of this map. The subscript operator of the map
694    /// gives back always the item what was last assigned to the value.
695    class InverseMap {
696    public:
697      /// \brief Constructor of the InverseMap.
698      ///
699      /// Constructor of the InverseMap.
700      InverseMap(const InvertableMap& _inverted) : inverted(_inverted) {}
701
702      /// The value type of the InverseMap.
703      typedef typename InvertableMap::Key Value;
704      /// The key type of the InverseMap.
705      typedef typename InvertableMap::Value Key;
706
707      /// \brief Subscript operator.
708      ///
709      /// Subscript operator. It gives back always the item
710      /// what was last assigned to the value.
711      Value operator[](const Key& key) const {
712        typename Container::const_iterator it = inverted.invMap.find(key);
713        return it->second;
714      }
715     
716    private:
717      const InvertableMap& inverted;
718    };
719
720    /// \brief It gives back the just readeable inverse map.
721    ///
722    /// It gives back the just readeable inverse map.
723    InverseMap inverse() const {
724      return InverseMap(*this);
725    }
726
727
728   
729  };
730
731  /// \brief Provides a mutable, continuous and unique descriptor for each
732  /// item in the graph.
733  ///
734  /// The DescriptorMap class provides a unique and continuous (but mutable)
735  /// descriptor (id) for each item of the same type (e.g. node) in the
736  /// graph. This id is <ul><li>\b unique: different items (nodes) get
737  /// different ids <li>\b continuous: the range of the ids is the set of
738  /// integers between 0 and \c n-1, where \c n is the number of the items of
739  /// this type (e.g. nodes) (so the id of a node can change if you delete an
740  /// other node, i.e. this id is mutable).  </ul> This map can be inverted
741  /// with its member class \c InverseMap.
742  ///
743  /// \param _Graph The graph class the \c DescriptorMap belongs to.
744  /// \param _Item The Item is the Key of the Map. It may be Node, Edge or
745  /// UndirEdge.
746  /// \param _Map A ReadWriteMap mapping from the item type to integer.
747  template <
748    typename _Graph,   
749    typename _Item,
750    typename _Map
751    = typename ItemSetTraits<_Graph, _Item>::template Map<int>::Parent
752  >
753  class DescriptorMap : protected _Map {
754
755    typedef _Item Item;
756    typedef _Map Map;
757
758  public:
759    /// The graph class of DescriptorMap.
760    typedef _Graph Graph;
761
762    /// The key type of DescriptorMap (Node, Edge, UndirEdge).
763    typedef typename _Map::Key Key;
764    /// The value type of DescriptorMap.
765    typedef typename _Map::Value Value;
766
767    /// \brief Constructor.
768    ///
769    /// Constructor for descriptor map.
770    DescriptorMap(const Graph& _graph) : Map(_graph) {
771      build();
772    }
773
774  protected:
775
776    /// \brief Add a new key to the map.
777    ///
778    /// Add a new key to the map. It is called by the
779    /// \c AlterationNotifier.
780    virtual void add(const Item& item) {
781      Map::add(item);
782      Map::set(item, invMap.size());
783      invMap.push_back(item);
784    }
785
786    /// \brief Erase the key from the map.
787    ///
788    /// Erase the key to the map. It is called by the
789    /// \c AlterationNotifier.
790    virtual void erase(const Item& item) {
791      Map::set(invMap.back(), Map::operator[](item));
792      invMap[Map::operator[](item)] = invMap.back();
793      invMap.pop_back();
794      Map::erase(item);
795    }
796
797    /// \brief Build the unique map.
798    ///
799    /// Build the unique map. It is called by the
800    /// \c AlterationNotifier.
801    virtual void build() {
802      Map::build();
803      Item it;
804      const typename Map::Graph* graph = Map::getGraph();
805      for (graph->first(it); it != INVALID; graph->next(it)) {
806        Map::set(it, invMap.size());
807        invMap.push_back(it);   
808      }     
809    }
810   
811    /// \brief Clear the keys from the map.
812    ///
813    /// Clear the keys from the map. It is called by the
814    /// \c AlterationNotifier.
815    virtual void clear() {
816      invMap.clear();
817      Map::clear();
818    }
819
820  public:
821
822    /// \brief Swaps the position of the two items in the map.
823    ///
824    /// Swaps the position of the two items in the map.
825    void swap(const Item& p, const Item& q) {
826      int pi = Map::operator[](p);
827      int qi = Map::operator[](q);
828      Map::set(p, qi);
829      invMap[qi] = p;
830      Map::set(q, pi);
831      invMap[pi] = q;
832    }
833
834    /// \brief Gives back the \e descriptor of the item.
835    ///
836    /// Gives back the mutable and unique \e descriptor of the map.
837    int operator[](const Item& item) const {
838      return Map::operator[](item);
839    }
840   
841  private:
842
843    typedef std::vector<Item> Container;
844    Container invMap;
845
846  public:
847    /// \brief The inverse map type of DescriptorMap.
848    ///
849    /// The inverse map type of DescriptorMap.
850    class InverseMap {
851    public:
852      /// \brief Constructor of the InverseMap.
853      ///
854      /// Constructor of the InverseMap.
855      InverseMap(const DescriptorMap& _inverted)
856        : inverted(_inverted) {}
857
858
859      /// The value type of the InverseMap.
860      typedef typename DescriptorMap::Key Value;
861      /// The key type of the InverseMap.
862      typedef typename DescriptorMap::Value Key;
863
864      /// \brief Subscript operator.
865      ///
866      /// Subscript operator. It gives back the item
867      /// that the descriptor belongs to currently.
868      Value operator[](const Key& key) const {
869        return inverted.invMap[key];
870      }
871
872      /// \brief Size of the map.
873      ///
874      /// Returns the size of the map.
875      int size() const {
876        return inverted.invMap.size();
877      }
878     
879    private:
880      const DescriptorMap& inverted;
881    };
882
883    /// \brief Gives back the inverse of the map.
884    ///
885    /// Gives back the inverse of the map.
886    const InverseMap inverse() const {
887      return InverseMap(*this);
888    }
889  };
890
891  /// \brief Returns the source of the given edge.
892  ///
893  /// The SourceMap gives back the source Node of the given edge.
894  /// \author Balazs Dezso
895  template <typename Graph>
896  class SourceMap {
897  public:
898
899    typedef True NeedCopy;
900
901    typedef typename Graph::Node Value;
902    typedef typename Graph::Edge Key;
903
904    /// \brief Constructor
905    ///
906    /// Constructor
907    /// \param _graph The graph that the map belongs to.
908    SourceMap(const Graph& _graph) : graph(_graph) {}
909
910    /// \brief The subscript operator.
911    ///
912    /// The subscript operator.
913    /// \param edge The edge
914    /// \return The source of the edge
915    Value operator[](const Key& edge) {
916      return graph.source(edge);
917    }
918
919  private:
920    const Graph& graph;
921  };
922
923  /// \brief Returns a \ref SourceMap class
924  ///
925  /// This function just returns an \ref SourceMap class.
926  /// \relates SourceMap
927  template <typename Graph>
928  inline SourceMap<Graph> sourceMap(const Graph& graph) {
929    return SourceMap<Graph>(graph);
930  }
931
932  /// \brief Returns the target of the given edge.
933  ///
934  /// The TargetMap gives back the target Node of the given edge.
935  /// \author Balazs Dezso
936  template <typename Graph>
937  class TargetMap {
938  public:
939
940    typedef True NeedCopy;
941
942    typedef typename Graph::Node Value;
943    typedef typename Graph::Edge Key;
944
945    /// \brief Constructor
946    ///
947    /// Constructor
948    /// \param _graph The graph that the map belongs to.
949    TargetMap(const Graph& _graph) : graph(_graph) {}
950
951    /// \brief The subscript operator.
952    ///
953    /// The subscript operator.
954    /// \param e The edge
955    /// \return The target of the edge
956    Value operator[](const Key& e) {
957      return graph.target(e);
958    }
959
960  private:
961    const Graph& graph;
962  };
963
964  /// \brief Returns a \ref TargetMap class
965  ///
966  /// This function just returns a \ref TargetMap class.
967  /// \relates TargetMap
968  template <typename Graph>
969  inline TargetMap<Graph> targetMap(const Graph& graph) {
970    return TargetMap<Graph>(graph);
971  }
972
973  /// \brief Returns the "forward" directed edge view of an undirected edge.
974  ///
975  /// Returns the "forward" directed edge view of an undirected edge.
976  /// \author Balazs Dezso
977  template <typename Graph>
978  class ForwardMap {
979  public:
980
981    typedef True NeedCopy;
982
983    typedef typename Graph::Edge Value;
984    typedef typename Graph::UndirEdge Key;
985
986    /// \brief Constructor
987    ///
988    /// Constructor
989    /// \param _graph The graph that the map belongs to.
990    ForwardMap(const Graph& _graph) : graph(_graph) {}
991
992    /// \brief The subscript operator.
993    ///
994    /// The subscript operator.
995    /// \param key An undirected edge
996    /// \return The "forward" directed edge view of undirected edge
997    Value operator[](const Key& key) const {
998      return graph.direct(key, true);
999    }
1000
1001  private:
1002    const Graph& graph;
1003  };
1004
1005  /// \brief Returns a \ref ForwardMap class
1006  ///
1007  /// This function just returns an \ref ForwardMap class.
1008  /// \relates ForwardMap
1009  template <typename Graph>
1010  inline ForwardMap<Graph> forwardMap(const Graph& graph) {
1011    return ForwardMap<Graph>(graph);
1012  }
1013
1014  /// \brief Returns the "backward" directed edge view of an undirected edge.
1015  ///
1016  /// Returns the "backward" directed edge view of an undirected edge.
1017  /// \author Balazs Dezso
1018  template <typename Graph>
1019  class BackwardMap {
1020  public:
1021    typedef True NeedCopy;
1022
1023    typedef typename Graph::Edge Value;
1024    typedef typename Graph::UndirEdge Key;
1025
1026    /// \brief Constructor
1027    ///
1028    /// Constructor
1029    /// \param _graph The graph that the map belongs to.
1030    BackwardMap(const Graph& _graph) : graph(_graph) {}
1031
1032    /// \brief The subscript operator.
1033    ///
1034    /// The subscript operator.
1035    /// \param key An undirected edge
1036    /// \return The "backward" directed edge view of undirected edge
1037    Value operator[](const Key& key) const {
1038      return graph.direct(key, false);
1039    }
1040
1041  private:
1042    const Graph& graph;
1043  };
1044
1045  /// \brief Returns a \ref BackwardMap class
1046
1047  /// This function just returns a \ref BackwardMap class.
1048  /// \relates BackwardMap
1049  template <typename Graph>
1050  inline BackwardMap<Graph> backwardMap(const Graph& graph) {
1051    return BackwardMap<Graph>(graph);
1052  }
1053
1054  template <typename _Graph>
1055  class DegMapBase {
1056  public:
1057   
1058    typedef _Graph Graph;
1059
1060  protected:
1061
1062    typedef typename Graph::template NodeMap<int> IntNodeMap;
1063   
1064  };
1065
1066  /// \brief Map of the node in-degrees.
1067  ///
1068  /// This map returns the in-degree of a node. Once it is constructed,
1069  /// the degrees are stored in a standard NodeMap, so each query is done
1070  /// in constant time. On the other hand, the values are updated automatically
1071  /// whenever the graph changes.
1072  ///
1073  /// \sa OutDegMap
1074
1075  template <typename _Graph>
1076  class InDegMap 
1077    : protected AlterationNotifier<typename _Graph::Edge>::ObserverBase {
1078
1079  public:
1080   
1081    typedef _Graph Graph;
1082    typedef int Value;
1083    typedef typename Graph::Node Key;
1084
1085  private:
1086
1087    class AutoNodeMap : public Graph::template NodeMap<int> {
1088    public:
1089
1090      typedef typename Graph::template NodeMap<int> Parent;
1091
1092      typedef typename Parent::Key Key;
1093      typedef typename Parent::Value Value;
1094     
1095      AutoNodeMap(const Graph& graph) : Parent(graph, 0) {}
1096     
1097      void add(const Key& key) {
1098        Parent::add(key);
1099        Parent::set(key, 0);
1100      }
1101    };
1102
1103  public:
1104
1105    /// \brief Constructor.
1106    ///
1107    /// Constructor for creating in-degree map.
1108    InDegMap(const Graph& _graph) : graph(_graph), deg(_graph) {
1109      AlterationNotifier<typename _Graph::Edge>
1110        ::ObserverBase::attach(graph.getNotifier(typename _Graph::Edge()));
1111     
1112      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1113        deg[it] = countInEdges(graph, it);
1114      }
1115    }
1116
1117    virtual ~InDegMap() {
1118      AlterationNotifier<typename _Graph::Edge>::
1119        ObserverBase::detach();
1120    }
1121   
1122    /// Gives back the in-degree of a Node.
1123    int operator[](const Key& key) const {
1124      return deg[key];
1125    }
1126
1127  protected:
1128   
1129    typedef typename Graph::Edge Edge;
1130
1131    virtual void add(const Edge& edge) {
1132      ++deg[graph.target(edge)];
1133    }
1134
1135    virtual void erase(const Edge& edge) {
1136      --deg[graph.target(edge)];
1137    }
1138
1139
1140    virtual void build() {
1141      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1142        deg[it] = countInEdges(graph, it);
1143      }     
1144    }
1145
1146    virtual void clear() {
1147      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1148        deg[it] = 0;
1149      }
1150    }
1151  private:
1152   
1153    const _Graph& graph;
1154    AutoNodeMap deg;
1155  };
1156
1157
1158  /// \brief Map of the node out-degrees.
1159  ///
1160  /// This map returns the out-degree of a node. Once it is constructed,
1161  /// the degrees are stored in a standard NodeMap, so each query is done
1162  /// in constant time. On the other hand, the values are updated automatically
1163  /// whenever the graph changes.
1164  ///
1165  /// \sa InDegMap
1166
1167  template <typename _Graph>
1168  class OutDegMap 
1169    : protected AlterationNotifier<typename _Graph::Edge>::ObserverBase {
1170
1171  public:
1172   
1173    typedef _Graph Graph;
1174    typedef int Value;
1175    typedef typename Graph::Node Key;
1176
1177  private:
1178
1179    class AutoNodeMap : public Graph::template NodeMap<int> {
1180    public:
1181
1182      typedef typename Graph::template NodeMap<int> Parent;
1183
1184      typedef typename Parent::Key Key;
1185      typedef typename Parent::Value Value;
1186     
1187      AutoNodeMap(const Graph& graph) : Parent(graph, 0) {}
1188     
1189      void add(const Key& key) {
1190        Parent::add(key);
1191        Parent::set(key, 0);
1192      }
1193    };
1194
1195  public:
1196
1197    /// \brief Constructor.
1198    ///
1199    /// Constructor for creating out-degree map.
1200    OutDegMap(const Graph& _graph) : graph(_graph), deg(_graph) {
1201      AlterationNotifier<typename _Graph::Edge>
1202        ::ObserverBase::attach(graph.getNotifier(typename _Graph::Edge()));
1203     
1204      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1205        deg[it] = countOutEdges(graph, it);
1206      }
1207    }
1208
1209    virtual ~OutDegMap() {
1210      AlterationNotifier<typename _Graph::Edge>::
1211        ObserverBase::detach();
1212    }
1213   
1214    /// Gives back the in-degree of a Node.
1215    int operator[](const Key& key) const {
1216      return deg[key];
1217    }
1218
1219  protected:
1220   
1221    typedef typename Graph::Edge Edge;
1222
1223    virtual void add(const Edge& edge) {
1224      ++deg[graph.source(edge)];
1225    }
1226
1227    virtual void erase(const Edge& edge) {
1228      --deg[graph.source(edge)];
1229    }
1230
1231
1232    virtual void build() {
1233      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1234        deg[it] = countOutEdges(graph, it);
1235      }     
1236    }
1237
1238    virtual void clear() {
1239      for(typename _Graph::NodeIt it(graph); it != INVALID; ++it) {
1240        deg[it] = 0;
1241      }
1242    }
1243  private:
1244   
1245    const _Graph& graph;
1246    AutoNodeMap deg;
1247  };
1248
1249  /// @}
1250
1251} //END OF NAMESPACE LEMON
1252
1253#endif
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