1 | /* -*- C++ -*- |
---|
2 | * 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 | |
---|
22 | LEMON provides flexible data structures |
---|
23 | to work with paths. |
---|
24 | |
---|
25 | All of them have the same interface, especially they can be built or extended |
---|
26 | using a standard Builder subclass. This make is easy to have e.g. the Dijkstra |
---|
27 | algorithm 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 | |
---|
48 | namespace 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 | /// \todo May we need just path for undirected graph instead of this. |
---|
387 | template<typename Graph> |
---|
388 | class UndirPath { |
---|
389 | public: |
---|
390 | /// Edge type of the underlying graph. |
---|
391 | typedef typename Graph::Edge GraphEdge; |
---|
392 | /// Node type of the underlying graph. |
---|
393 | typedef typename Graph::Node GraphNode; |
---|
394 | class NodeIt; |
---|
395 | class EdgeIt; |
---|
396 | |
---|
397 | protected: |
---|
398 | const Graph *gr; |
---|
399 | typedef std::vector<GraphEdge> Container; |
---|
400 | Container edges; |
---|
401 | |
---|
402 | public: |
---|
403 | |
---|
404 | /// \param _G The graph in which the path is. |
---|
405 | /// |
---|
406 | UndirPath(const Graph &_G) : gr(&_G) {} |
---|
407 | |
---|
408 | /// \brief Subpath constructor. |
---|
409 | /// |
---|
410 | /// Subpath defined by two nodes. |
---|
411 | /// \warning It is an error if the two edges are not in order! |
---|
412 | UndirPath(const UndirPath &P, const NodeIt &a, const NodeIt &b) { |
---|
413 | gr = P.gr; |
---|
414 | edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx); |
---|
415 | } |
---|
416 | |
---|
417 | /// \brief Subpath constructor. |
---|
418 | /// |
---|
419 | /// Subpath defined by two edges. Contains edges in [a,b) |
---|
420 | /// \warning It is an error if the two edges are not in order! |
---|
421 | UndirPath(const UndirPath &P, const EdgeIt &a, const EdgeIt &b) { |
---|
422 | gr = P.gr; |
---|
423 | edges.insert(edges.end(), P.edges.begin()+a.idx, P.edges.begin()+b.idx); |
---|
424 | } |
---|
425 | |
---|
426 | /// Length of the path. |
---|
427 | size_t length() const { return edges.size(); } |
---|
428 | /// Returns whether the path is empty. |
---|
429 | bool empty() const { return edges.empty(); } |
---|
430 | |
---|
431 | /// Resets the path to an empty path. |
---|
432 | void clear() { edges.clear(); } |
---|
433 | |
---|
434 | /// \brief Starting point of the path. |
---|
435 | /// |
---|
436 | /// Starting point of the path. |
---|
437 | /// Returns INVALID if the path is empty. |
---|
438 | GraphNode source() const { |
---|
439 | return empty() ? INVALID : gr->source(edges[0]); |
---|
440 | } |
---|
441 | /// \brief End point of the path. |
---|
442 | /// |
---|
443 | /// End point of the path. |
---|
444 | /// Returns INVALID if the path is empty. |
---|
445 | GraphNode target() const { |
---|
446 | return empty() ? INVALID : gr->target(edges[length()-1]); |
---|
447 | } |
---|
448 | |
---|
449 | /// \brief Initializes node or edge iterator to point to the first |
---|
450 | /// node or edge. |
---|
451 | /// |
---|
452 | /// \sa nth |
---|
453 | template<typename It> |
---|
454 | It& first(It &i) const { return i=It(*this); } |
---|
455 | |
---|
456 | /// \brief Initializes node iterator to point to the node of a given index. |
---|
457 | NodeIt& nth(NodeIt &i, int n) const { |
---|
458 | return i=NodeIt(*this, n); |
---|
459 | } |
---|
460 | |
---|
461 | /// \brief Initializes edge iterator to point to the edge of a given index. |
---|
462 | EdgeIt& nth(EdgeIt &i, int n) const { |
---|
463 | return i=EdgeIt(*this, n); |
---|
464 | } |
---|
465 | |
---|
466 | /// Checks validity of a node or edge iterator. |
---|
467 | template<typename It> |
---|
468 | static |
---|
469 | bool valid(const It &i) { return i.valid(); } |
---|
470 | |
---|
471 | /// Steps the given node or edge iterator. |
---|
472 | template<typename It> |
---|
473 | static |
---|
474 | It& next(It &e) { |
---|
475 | return ++e; |
---|
476 | } |
---|
477 | |
---|
478 | /// \brief Returns node iterator pointing to the target node of the |
---|
479 | /// given edge iterator. |
---|
480 | NodeIt target(const EdgeIt& e) const { |
---|
481 | return NodeIt(*this, e.idx+1); |
---|
482 | } |
---|
483 | |
---|
484 | /// \brief Returns node iterator pointing to the source node of the |
---|
485 | /// given edge iterator. |
---|
486 | NodeIt source(const EdgeIt& e) const { |
---|
487 | return NodeIt(*this, e.idx); |
---|
488 | } |
---|
489 | |
---|
490 | |
---|
491 | |
---|
492 | /** |
---|
493 | * \brief Iterator class to iterate on the edges of the paths |
---|
494 | * |
---|
495 | * This class is used to iterate on the edges of the paths |
---|
496 | * |
---|
497 | * Of course it converts to Graph::Edge |
---|
498 | * |
---|
499 | * \todo Its interface differs from the standard edge iterator. |
---|
500 | * Yes, it shouldn't. |
---|
501 | */ |
---|
502 | class EdgeIt { |
---|
503 | friend class UndirPath; |
---|
504 | |
---|
505 | int idx; |
---|
506 | const UndirPath *p; |
---|
507 | public: |
---|
508 | /// Default constructor |
---|
509 | EdgeIt() {} |
---|
510 | /// Invalid constructor |
---|
511 | EdgeIt(Invalid) : idx(-1), p(0) {} |
---|
512 | /// Constructor with starting point |
---|
513 | EdgeIt(const UndirPath &_p, int _idx = 0) : |
---|
514 | idx(_idx), p(&_p) { validate(); } |
---|
515 | |
---|
516 | ///Validity check |
---|
517 | bool valid() const { return idx!=-1; } |
---|
518 | |
---|
519 | ///Conversion to Graph::Edge |
---|
520 | operator GraphEdge () const { |
---|
521 | return valid() ? p->edges[idx] : INVALID; |
---|
522 | } |
---|
523 | /// Next edge |
---|
524 | EdgeIt& operator++() { ++idx; validate(); return *this; } |
---|
525 | |
---|
526 | /// Comparison operator |
---|
527 | bool operator==(const EdgeIt& e) const { return idx==e.idx; } |
---|
528 | /// Comparison operator |
---|
529 | bool operator!=(const EdgeIt& e) const { return idx!=e.idx; } |
---|
530 | /// Comparison operator |
---|
531 | bool operator<(const EdgeIt& e) const { return idx<e.idx; } |
---|
532 | |
---|
533 | private: |
---|
534 | // FIXME: comparison between signed and unsigned... |
---|
535 | // Jo ez igy? Vagy esetleg legyen a length() int? |
---|
536 | void validate() { if( size_t(idx) >= p->length() ) idx=-1; } |
---|
537 | }; |
---|
538 | |
---|
539 | /** |
---|
540 | * \brief Iterator class to iterate on the nodes of the paths |
---|
541 | * |
---|
542 | * This class is used to iterate on the nodes of the paths |
---|
543 | * |
---|
544 | * Of course it converts to Graph::Node |
---|
545 | * |
---|
546 | * \todo Its interface differs from the standard node iterator. |
---|
547 | * Yes, it shouldn't. |
---|
548 | */ |
---|
549 | class NodeIt { |
---|
550 | friend class UndirPath; |
---|
551 | |
---|
552 | int idx; |
---|
553 | const UndirPath *p; |
---|
554 | public: |
---|
555 | /// Default constructor |
---|
556 | NodeIt() {} |
---|
557 | /// Invalid constructor |
---|
558 | NodeIt(Invalid) : idx(-1), p(0) {} |
---|
559 | /// Constructor with starting point |
---|
560 | NodeIt(const UndirPath &_p, int _idx = 0) : |
---|
561 | idx(_idx), p(&_p) { validate(); } |
---|
562 | |
---|
563 | ///Validity check |
---|
564 | bool valid() const { return idx!=-1; } |
---|
565 | |
---|
566 | ///Conversion to Graph::Node |
---|
567 | operator const GraphNode& () const { |
---|
568 | if(idx >= p->length()) |
---|
569 | return p->target(); |
---|
570 | else if(idx >= 0) |
---|
571 | return p->gr->source(p->edges[idx]); |
---|
572 | else |
---|
573 | return INVALID; |
---|
574 | } |
---|
575 | /// Next node |
---|
576 | NodeIt& operator++() { ++idx; validate(); return *this; } |
---|
577 | |
---|
578 | /// Comparison operator |
---|
579 | bool operator==(const NodeIt& e) const { return idx==e.idx; } |
---|
580 | /// Comparison operator |
---|
581 | bool operator!=(const NodeIt& e) const { return idx!=e.idx; } |
---|
582 | /// Comparison operator |
---|
583 | bool operator<(const NodeIt& e) const { return idx<e.idx; } |
---|
584 | |
---|
585 | private: |
---|
586 | void validate() { if( size_t(idx) > p->length() ) idx=-1; } |
---|
587 | }; |
---|
588 | |
---|
589 | friend class Builder; |
---|
590 | |
---|
591 | /** |
---|
592 | * \brief Class to build paths |
---|
593 | * |
---|
594 | * This class is used to fill a path with edges. |
---|
595 | * |
---|
596 | * You can push new edges to the front and to the back of the path in |
---|
597 | * arbitrary order then you should commit these changes to the graph. |
---|
598 | * |
---|
599 | * Fundamentally, for most "Paths" (classes fulfilling the |
---|
600 | * PathConcept) while the builder is active (after the first modifying |
---|
601 | * operation and until the commit()) the original Path is in a |
---|
602 | * "transitional" state (operations ot it have undefined result). But |
---|
603 | * in the case of UndirPath the original path is unchanged until the |
---|
604 | * commit. However we don't recomend that you use this feature. |
---|
605 | */ |
---|
606 | class Builder { |
---|
607 | UndirPath &P; |
---|
608 | Container front, back; |
---|
609 | |
---|
610 | public: |
---|
611 | ///\param _p the path you want to fill in. |
---|
612 | /// |
---|
613 | Builder(UndirPath &_p) : P(_p) {} |
---|
614 | |
---|
615 | /// Sets the starting node of the path. |
---|
616 | |
---|
617 | /// Sets the starting node of the path. Edge added to the path |
---|
618 | /// afterwards have to be incident to this node. |
---|
619 | /// It should be called if and only if |
---|
620 | /// the path is empty and before any call to |
---|
621 | /// \ref pushFront() or \ref pushBack() |
---|
622 | void setStartNode(const GraphNode &) {} |
---|
623 | |
---|
624 | ///Push a new edge to the front of the path |
---|
625 | |
---|
626 | ///Push a new edge to the front of the path. |
---|
627 | ///\sa setStartNode |
---|
628 | void pushFront(const GraphEdge& e) { |
---|
629 | front.push_back(e); |
---|
630 | } |
---|
631 | |
---|
632 | ///Push a new edge to the back of the path |
---|
633 | |
---|
634 | ///Push a new edge to the back of the path. |
---|
635 | ///\sa setStartNode |
---|
636 | void pushBack(const GraphEdge& e) { |
---|
637 | back.push_back(e); |
---|
638 | } |
---|
639 | |
---|
640 | ///Commit the changes to the path. |
---|
641 | void commit() { |
---|
642 | if( !(front.empty() && back.empty()) ) { |
---|
643 | Container tmp; |
---|
644 | tmp.reserve(front.size()+back.size()+P.length()); |
---|
645 | tmp.insert(tmp.end(), front.rbegin(), front.rend()); |
---|
646 | tmp.insert(tmp.end(), P.edges.begin(), P.edges.end()); |
---|
647 | tmp.insert(tmp.end(), back.begin(), back.end()); |
---|
648 | P.edges.swap(tmp); |
---|
649 | front.clear(); |
---|
650 | back.clear(); |
---|
651 | } |
---|
652 | } |
---|
653 | |
---|
654 | |
---|
655 | ///Reserve storage for the builder in advance. |
---|
656 | |
---|
657 | ///If you know a reasonable upper bound of the number of the edges |
---|
658 | ///to add to the front, using this function you can speed up the building. |
---|
659 | |
---|
660 | void reserveFront(size_t r) {front.reserve(r);} |
---|
661 | |
---|
662 | ///Reserve storage for the builder in advance. |
---|
663 | |
---|
664 | ///If you know a reasonable upper bound of the number of the edges |
---|
665 | ///to add to the back, using this function you can speed up the building. |
---|
666 | |
---|
667 | void reserveBack(size_t r) {back.reserve(r);} |
---|
668 | |
---|
669 | private: |
---|
670 | bool empty() { |
---|
671 | return front.empty() && back.empty() && P.empty(); |
---|
672 | } |
---|
673 | |
---|
674 | GraphNode source() const { |
---|
675 | if( ! front.empty() ) |
---|
676 | return P.gr->source(front[front.size()-1]); |
---|
677 | else if( ! P.empty() ) |
---|
678 | return P.gr->source(P.edges[0]); |
---|
679 | else if( ! back.empty() ) |
---|
680 | return P.gr->source(back[0]); |
---|
681 | else |
---|
682 | return INVALID; |
---|
683 | } |
---|
684 | GraphNode target() const { |
---|
685 | if( ! back.empty() ) |
---|
686 | return P.gr->target(back[back.size()-1]); |
---|
687 | else if( ! P.empty() ) |
---|
688 | return P.gr->target(P.edges[P.length()-1]); |
---|
689 | else if( ! front.empty() ) |
---|
690 | return P.gr->target(front[0]); |
---|
691 | else |
---|
692 | return INVALID; |
---|
693 | } |
---|
694 | |
---|
695 | }; |
---|
696 | |
---|
697 | }; |
---|
698 | |
---|
699 | |
---|
700 | ///@} |
---|
701 | |
---|
702 | } // namespace lemon |
---|
703 | |
---|
704 | #endif // LEMON_PATH_H |
---|