COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/path.h @ 1359:1581f961cfaa

Last change on this file since 1359:1581f961cfaa was 1359:1581f961cfaa, checked in by Alpar Juttner, 15 years ago

Correct the english name of EGRES.

File size: 19.7 KB
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1/* -*- C++ -*-
2 * src/lemon/path.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/**
18@defgroup paths Path Structures
19@ingroup datas
20\brief Path structures implemented in LEMON.
21
22LEMON provides flexible data structures
23to work with paths.
24
25All of them have the same interface, especially they can be built or extended
26using a standard Builder subclass. This make is easy to have e.g. the Dijkstra
27algorithm to store its result in any kind of path structure.
28
29\sa lemon::concept::Path
30
31*/
32
33///\ingroup paths
34///\file
35///\brief Classes for representing paths in graphs.
36///
37///\todo Iterators have obsolete style
38
39#ifndef LEMON_PATH_H
40#define LEMON_PATH_H
41
42#include <deque>
43#include <vector>
44#include <algorithm>
45
46#include <lemon/invalid.h>
47
48namespace lemon {
49
50  /// \addtogroup paths
51  /// @{
52
53
54  //! \brief A structure for representing directed paths in a graph.
55  //!
56  //! A structure for representing directed path in a graph.
57  //! \param Graph The graph type in which the path is.
58  //! \param DM DebugMode, defaults to DefaultDebugMode.
59  //!
60  //! In a sense, the path can be treated as a graph, for is has \c NodeIt
61  //! and \c EdgeIt with the same usage. These types converts to the \c Node
62  //! and \c Edge of the original graph.
63  //!
64  //! \todo Thoroughfully check all the range and consistency tests.
65  template<typename Graph>
66  class DirPath {
67  public:
68    /// Edge type of the underlying graph.
69    typedef typename Graph::Edge GraphEdge;
70    /// Node type of the underlying graph.
71    typedef typename Graph::Node GraphNode;
72    class NodeIt;
73    class EdgeIt;
74
75  protected:
76    const Graph *gr;
77    typedef std::vector<GraphEdge> Container;
78    Container edges;
79
80  public:
81
82    /// \param _G The graph in which the path is.
83    ///
84    DirPath(const Graph &_G) : gr(&_G) {}
85
86    /// \brief Subpath constructor.
87    ///
88    /// Subpath defined by two nodes.
89    /// \warning It is an error if the two edges are not in order!
90    DirPath(const DirPath &P, const NodeIt &a, const NodeIt &b) {
91      gr = P.gr;
92      edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
93    }
94
95    /// \brief Subpath constructor.
96    ///
97    /// Subpath defined by two edges. Contains edges in [a,b)
98    /// \warning It is an error if the two edges are not in order!
99    DirPath(const DirPath &P, const EdgeIt &a, const EdgeIt &b) {
100      gr = P.gr;
101      edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
102    }
103
104    /// Length of the path.
105    int length() const { return edges.size(); }
106    /// Returns whether the path is empty.
107    bool empty() const { return edges.empty(); }
108
109    /// Resets the path to an empty path.
110    void clear() { edges.clear(); }
111
112    /// \brief Starting point of the path.
113    ///
114    /// Starting point of the path.
115    /// Returns INVALID if the path is empty.
116    GraphNode source() const {
117      return empty() ? INVALID : gr->source(edges[0]);
118    }
119    /// \brief End point of the path.
120    ///
121    /// End point of the path.
122    /// Returns INVALID if the path is empty.
123    GraphNode target() const {
124      return empty() ? INVALID : gr->target(edges[length()-1]);
125    }
126
127    /// \brief Initializes node or edge iterator to point to the first
128    /// node or edge.
129    ///
130    /// \sa nth
131    template<typename It>
132    It& first(It &i) const { return i=It(*this); }
133
134    /// \brief Initializes node iterator to point to the node of a given index.
135    NodeIt& nth(NodeIt &i, int n) const {
136      return i=NodeIt(*this, n);
137    }
138
139    /// \brief Initializes edge iterator to point to the edge of a given index.
140    EdgeIt& nth(EdgeIt &i, int n) const {
141      return i=EdgeIt(*this, n);
142    }
143
144    /// \brief Returns node iterator pointing to the target node of the
145    /// given edge iterator.
146    NodeIt target(const EdgeIt& e) const {
147      return NodeIt(*this, e.idx+1);
148    }
149
150    /// \brief Returns node iterator pointing to the source node of the
151    /// given edge iterator.
152    NodeIt source(const EdgeIt& e) const {
153      return NodeIt(*this, e.idx);
154    }
155
156
157    /* Iterator classes */
158
159    /**
160     * \brief Iterator class to iterate on the edges of the paths
161     *
162     * This class is used to iterate on the edges of the paths
163     *
164     * Of course it converts to Graph::Edge
165     *
166     */
167    class EdgeIt {
168      friend class DirPath;
169
170      int idx;
171      const DirPath *p;
172    public:
173      /// Default constructor
174      EdgeIt() {}
175      /// Invalid constructor
176      EdgeIt(Invalid) : idx(-1), p(0) {}
177      /// Constructor with starting point
178      EdgeIt(const DirPath &_p, int _idx = 0) :
179        idx(_idx), p(&_p) { validate(); }
180
181      ///Validity check
182      bool valid() const { return idx!=-1; }
183
184      ///Conversion to Graph::Edge
185      operator GraphEdge () const {
186        return valid() ? p->edges[idx] : INVALID;
187      }
188
189      /// Next edge
190      EdgeIt& operator++() { ++idx; validate(); return *this; }
191
192      /// Comparison operator
193      bool operator==(const EdgeIt& e) const { return idx==e.idx; }
194      /// Comparison operator
195      bool operator!=(const EdgeIt& e) const { return idx!=e.idx; }
196      /// Comparison operator
197      bool operator<(const EdgeIt& e) const { return idx<e.idx; }
198
199    private:
200      void validate() { if(idx >= p->length() ) idx=-1; }
201    };
202
203    /**
204     * \brief Iterator class to iterate on the nodes of the paths
205     *
206     * This class is used to iterate on the nodes of the paths
207     *
208     * Of course it converts to Graph::Node
209     *
210     */
211    class NodeIt {
212      friend class DirPath;
213
214      int idx;
215      const DirPath *p;
216    public:
217      /// Default constructor
218      NodeIt() {}
219      /// Invalid constructor
220      NodeIt(Invalid) : idx(-1), p(0) {}
221      /// Constructor with starting point
222      NodeIt(const DirPath &_p, int _idx = 0) :
223        idx(_idx), p(&_p) { validate(); }
224
225      ///Validity check
226      bool valid() const { return idx!=-1; }
227
228      ///Conversion to Graph::Node
229      operator const GraphNode& () const {
230        if(idx >= p->length())
231          return p->target();
232        else if(idx >= 0)
233          return p->gr->source(p->edges[idx]);
234        else
235          return INVALID;
236      }
237      /// Next node
238      NodeIt& operator++() { ++idx; validate(); return *this; }
239
240      /// Comparison operator
241      bool operator==(const NodeIt& e) const { return idx==e.idx; }
242      /// Comparison operator
243      bool operator!=(const NodeIt& e) const { return idx!=e.idx; }
244      /// Comparison operator
245      bool operator<(const NodeIt& e) const { return idx<e.idx; }
246
247    private:
248      void validate() { if(idx > p->length() ) idx=-1; }
249    };
250
251    friend class Builder;
252
253    /**
254     * \brief Class to build paths
255     *
256     * This class is used to fill a path with edges.
257     *
258     * You can push new edges to the front and to the back of the path in
259     * arbitrary order then you should commit these changes to the graph.
260     *
261     * Fundamentally, for most "Paths" (classes fulfilling the
262     * PathConcept) while the builder is active (after the first modifying
263     * operation and until the commit()) the original Path is in a
264     * "transitional" state (operations on it have undefined result). But
265     * in the case of DirPath the original path remains unchanged until the
266     * commit. However we don't recomend that you use this feature.
267     */
268    class Builder {
269      DirPath &P;
270      Container front, back;
271
272    public:
273      ///\param _p the path you want to fill in.
274      ///
275      Builder(DirPath &_p) : P(_p) {}
276
277      /// Sets the starting node of the path.
278
279      /// Sets the starting node of the path. Edge added to the path
280      /// afterwards have to be incident to this node.
281      /// It should be called if and only if
282      /// the path is empty and before any call to
283      /// \ref pushFront() or \ref pushBack()
284      void setStartNode(const GraphNode &) {}
285
286      ///Push a new edge to the front of the path
287
288      ///Push a new edge to the front of the path.
289      ///\sa setStartNode
290      void pushFront(const GraphEdge& e) {
291        front.push_back(e);
292      }
293
294      ///Push a new edge to the back of the path
295
296      ///Push a new edge to the back of the path.
297      ///\sa setStartNode
298      void pushBack(const GraphEdge& e) {
299        back.push_back(e);
300      }
301
302      ///Commit the changes to the path.
303      void commit() {
304        if( !front.empty() || !back.empty() ) {
305          Container tmp;
306          tmp.reserve(front.size()+back.size()+P.length());
307          tmp.insert(tmp.end(), front.rbegin(), front.rend());
308          tmp.insert(tmp.end(), P.edges.begin(), P.edges.end());
309          tmp.insert(tmp.end(), back.begin(), back.end());
310          P.edges.swap(tmp);
311          front.clear();
312          back.clear();
313        }
314      }
315
316      ///Reserve storage for the builder in advance.
317
318      ///If you know a reasonable upper bound of the number of the edges
319      ///to add to the front, using this function you can speed up the building.
320
321      void reserveFront(size_t r) {front.reserve(r);}
322
323      ///Reserve storage for the builder in advance.
324
325      ///If you know a reasonable upper bound of the number of the edges
326      ///to add to the back, using this function you can speed up the building.
327
328      void reserveBack(size_t r) {back.reserve(r);}
329
330    private:
331      bool empty() {
332        return front.empty() && back.empty() && P.empty();
333      }
334
335      GraphNode source() const {
336        if( ! front.empty() )
337          return P.gr->source(front[front.size()-1]);
338        else if( ! P.empty() )
339          return P.gr->source(P.edges[0]);
340        else if( ! back.empty() )
341          return P.gr->source(back[0]);
342        else
343          return INVALID;
344      }
345      GraphNode target() const {
346        if( ! back.empty() )
347          return P.gr->target(back[back.size()-1]);
348        else if( ! P.empty() )
349          return P.gr->target(P.edges[P.length()-1]);
350        else if( ! front.empty() )
351          return P.gr->target(front[0]);
352        else
353          return INVALID;
354      }
355
356    };
357
358  };
359
360
361
362
363
364
365
366
367
368
369  /**********************************************************************/
370
371
372  //! \brief A structure for representing undirected path in a graph.
373  //!
374  //! A structure for representing undirected path in a graph. Ie. this is
375  //! a path in a \e directed graph but the edges should not be directed
376  //! forward.
377  //!
378  //! \param Graph The graph type in which the path is.
379  //! \param DM DebugMode, defaults to DefaultDebugMode.
380  //!
381  //! In a sense, the path can be treated as a graph, for is has \c NodeIt
382  //! and \c EdgeIt with the same usage. These types converts to the \c Node
383  //! and \c Edge of the original graph.
384  //!
385  //! \todo Thoroughfully check all the range and consistency tests.
386  template<typename Graph>
387  class UndirPath {
388  public:
389    /// Edge type of the underlying graph.
390    typedef typename Graph::Edge GraphEdge;
391     /// Node type of the underlying graph.
392   typedef typename Graph::Node GraphNode;
393    class NodeIt;
394    class EdgeIt;
395
396  protected:
397    const Graph *gr;
398    typedef std::vector<GraphEdge> Container;
399    Container edges;
400
401  public:
402
403    /// \param _G The graph in which the path is.
404    ///
405    UndirPath(const Graph &_G) : gr(&_G) {}
406
407    /// \brief Subpath constructor.
408    ///
409    /// Subpath defined by two nodes.
410    /// \warning It is an error if the two edges are not in order!
411    UndirPath(const UndirPath &P, const NodeIt &a, const NodeIt &b) {
412      gr = P.gr;
413      edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
414    }
415
416    /// \brief Subpath constructor.
417    ///
418    /// Subpath defined by two edges. Contains edges in [a,b)
419    /// \warning It is an error if the two edges are not in order!
420    UndirPath(const UndirPath &P, const EdgeIt &a, const EdgeIt &b) {
421      gr = P.gr;
422      edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx);
423    }
424
425    /// Length of the path.
426    size_t length() const { return edges.size(); }
427    /// Returns whether the path is empty.
428    bool empty() const { return edges.empty(); }
429
430    /// Resets the path to an empty path.
431    void clear() { edges.clear(); }
432
433    /// \brief Starting point of the path.
434    ///
435    /// Starting point of the path.
436    /// Returns INVALID if the path is empty.
437    GraphNode source() const {
438      return empty() ? INVALID : gr->source(edges[0]);
439    }
440    /// \brief End point of the path.
441    ///
442    /// End point of the path.
443    /// Returns INVALID if the path is empty.
444    GraphNode target() const {
445      return empty() ? INVALID : gr->target(edges[length()-1]);
446    }
447
448    /// \brief Initializes node or edge iterator to point to the first
449    /// node or edge.
450    ///
451    /// \sa nth
452    template<typename It>
453    It& first(It &i) const { return i=It(*this); }
454
455    /// \brief Initializes node iterator to point to the node of a given index.
456    NodeIt& nth(NodeIt &i, int n) const {
457      return i=NodeIt(*this, n);
458    }
459
460    /// \brief Initializes edge iterator to point to the edge of a given index.
461    EdgeIt& nth(EdgeIt &i, int n) const {
462      return i=EdgeIt(*this, n);
463    }
464
465    /// Checks validity of a node or edge iterator.
466    template<typename It>
467    static
468    bool valid(const It &i) { return i.valid(); }
469
470    /// Steps the given node or edge iterator.
471    template<typename It>
472    static
473    It& next(It &e) {
474      return ++e;
475    }
476
477    /// \brief Returns node iterator pointing to the target node of the
478    /// given edge iterator.
479    NodeIt target(const EdgeIt& e) const {
480      return NodeIt(*this, e.idx+1);
481    }
482
483    /// \brief Returns node iterator pointing to the source node of the
484    /// given edge iterator.
485    NodeIt source(const EdgeIt& e) const {
486      return NodeIt(*this, e.idx);
487    }
488
489
490
491    /**
492     * \brief Iterator class to iterate on the edges of the paths
493     *
494     * This class is used to iterate on the edges of the paths
495     *
496     * Of course it converts to Graph::Edge
497     *
498     * \todo Its interface differs from the standard edge iterator.
499     * Yes, it shouldn't.
500     */
501    class EdgeIt {
502      friend class UndirPath;
503
504      int idx;
505      const UndirPath *p;
506    public:
507      /// Default constructor
508      EdgeIt() {}
509      /// Invalid constructor
510      EdgeIt(Invalid) : idx(-1), p(0) {}
511      /// Constructor with starting point
512      EdgeIt(const UndirPath &_p, int _idx = 0) :
513        idx(_idx), p(&_p) { validate(); }
514
515      ///Validity check
516      bool valid() const { return idx!=-1; }
517
518      ///Conversion to Graph::Edge
519      operator GraphEdge () const {
520        return valid() ? p->edges[idx] : INVALID;
521      }
522      /// Next edge
523     EdgeIt& operator++() { ++idx; validate(); return *this; }
524
525      /// Comparison operator
526      bool operator==(const EdgeIt& e) const { return idx==e.idx; }
527      /// Comparison operator
528      bool operator!=(const EdgeIt& e) const { return idx!=e.idx; }
529      /// Comparison operator
530      bool operator<(const EdgeIt& e) const { return idx<e.idx; }
531
532    private:
533      // FIXME: comparison between signed and unsigned...
534      // Jo ez igy? Vagy esetleg legyen a length() int?
535      void validate() { if( size_t(idx) >= p->length() ) idx=-1; }
536    };
537
538    /**
539     * \brief Iterator class to iterate on the nodes of the paths
540     *
541     * This class is used to iterate on the nodes of the paths
542     *
543     * Of course it converts to Graph::Node
544     *
545     * \todo Its interface differs from the standard node iterator.
546     * Yes, it shouldn't.
547     */
548    class NodeIt {
549      friend class UndirPath;
550
551      int idx;
552      const UndirPath *p;
553    public:
554      /// Default constructor
555      NodeIt() {}
556      /// Invalid constructor
557      NodeIt(Invalid) : idx(-1), p(0) {}
558      /// Constructor with starting point
559      NodeIt(const UndirPath &_p, int _idx = 0) :
560        idx(_idx), p(&_p) { validate(); }
561
562      ///Validity check
563      bool valid() const { return idx!=-1; }
564
565      ///Conversion to Graph::Node
566      operator const GraphNode& () const {
567        if(idx >= p->length())
568          return p->target();
569        else if(idx >= 0)
570          return p->gr->source(p->edges[idx]);
571        else
572          return INVALID;
573      }
574      /// Next node
575      NodeIt& operator++() { ++idx; validate(); return *this; }
576
577      /// Comparison operator
578      bool operator==(const NodeIt& e) const { return idx==e.idx; }
579      /// Comparison operator
580      bool operator!=(const NodeIt& e) const { return idx!=e.idx; }
581       /// Comparison operator
582     bool operator<(const NodeIt& e) const { return idx<e.idx; }
583
584    private:
585      void validate() { if( size_t(idx) > p->length() ) idx=-1; }
586    };
587
588    friend class Builder;
589
590    /**
591     * \brief Class to build paths
592     *
593     * This class is used to fill a path with edges.
594     *
595     * You can push new edges to the front and to the back of the path in
596     * arbitrary order then you should commit these changes to the graph.
597     *
598     * Fundamentally, for most "Paths" (classes fulfilling the
599     * PathConcept) while the builder is active (after the first modifying
600     * operation and until the commit()) the original Path is in a
601     * "transitional" state (operations ot it have undefined result). But
602     * in the case of UndirPath the original path is unchanged until the
603     * commit. However we don't recomend that you use this feature.
604     */
605    class Builder {
606      UndirPath &P;
607      Container front, back;
608
609    public:
610      ///\param _p the path you want to fill in.
611      ///
612      Builder(UndirPath &_p) : P(_p) {}
613
614      /// Sets the starting node of the path.
615
616      /// Sets the starting node of the path. Edge added to the path
617      /// afterwards have to be incident to this node.
618      /// It should be called if and only if
619      /// the path is empty and before any call to
620      /// \ref pushFront() or \ref pushBack()
621      void setStartNode(const GraphNode &) {}
622
623      ///Push a new edge to the front of the path
624
625      ///Push a new edge to the front of the path.
626      ///\sa setStartNode
627      void pushFront(const GraphEdge& e) {
628        front.push_back(e);
629      }
630
631      ///Push a new edge to the back of the path
632
633      ///Push a new edge to the back of the path.
634      ///\sa setStartNode
635      void pushBack(const GraphEdge& e) {
636        back.push_back(e);
637      }
638
639      ///Commit the changes to the path.
640      void commit() {
641        if( !(front.empty() && back.empty()) ) {
642          Container tmp;
643          tmp.reserve(front.size()+back.size()+P.length());
644          tmp.insert(tmp.end(), front.rbegin(), front.rend());
645          tmp.insert(tmp.end(), P.edges.begin(), P.edges.end());
646          tmp.insert(tmp.end(), back.begin(), back.end());
647          P.edges.swap(tmp);
648          front.clear();
649          back.clear();
650        }
651      }
652
653
654      ///Reserve storage for the builder in advance.
655
656      ///If you know a reasonable upper bound of the number of the edges
657      ///to add to the front, using this function you can speed up the building.
658
659      void reserveFront(size_t r) {front.reserve(r);}
660
661      ///Reserve storage for the builder in advance.
662
663      ///If you know a reasonable upper bound of the number of the edges
664      ///to add to the back, using this function you can speed up the building.
665
666      void reserveBack(size_t r) {back.reserve(r);}
667
668    private:
669      bool empty() {
670        return front.empty() && back.empty() && P.empty();
671      }
672
673      GraphNode source() const {
674        if( ! front.empty() )
675          return P.gr->source(front[front.size()-1]);
676        else if( ! P.empty() )
677          return P.gr->source(P.edges[0]);
678        else if( ! back.empty() )
679          return P.gr->source(back[0]);
680        else
681          return INVALID;
682      }
683      GraphNode target() const {
684        if( ! back.empty() )
685          return P.gr->target(back[back.size()-1]);
686        else if( ! P.empty() )
687          return P.gr->target(P.edges[P.length()-1]);
688        else if( ! front.empty() )
689          return P.gr->target(front[0]);
690        else
691          return INVALID;
692      }
693
694    };
695
696  };
697
698
699  ///@}
700
701} // namespace lemon
702
703#endif // LEMON_PATH_H
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