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/* -*- C++ -*- |
2 | 2 |
* |
3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library |
4 | 4 |
* |
5 | 5 |
* Copyright (C) 2003-2008 |
6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
8 | 8 |
* |
9 | 9 |
* Permission to use, modify and distribute this software is granted |
10 | 10 |
* provided that this copyright notice appears in all copies. For |
11 | 11 |
* precise terms see the accompanying LICENSE file. |
12 | 12 |
* |
13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
14 | 14 |
* express or implied, and with no claim as to its suitability for any |
15 | 15 |
* purpose. |
16 | 16 |
* |
17 | 17 |
*/ |
18 | 18 |
|
19 | 19 |
///\ingroup paths |
20 | 20 |
///\file |
21 | 21 |
///\brief Classes for representing paths in digraphs. |
22 | 22 |
/// |
23 | 23 |
|
24 | 24 |
#ifndef LEMON_PATH_H |
25 | 25 |
#define LEMON_PATH_H |
26 | 26 |
|
27 | 27 |
#include <vector> |
28 | 28 |
#include <algorithm> |
29 | 29 |
|
30 | 30 |
#include <lemon/path_utils.h> |
31 | 31 |
#include <lemon/error.h> |
32 | 32 |
#include <lemon/bits/invalid.h> |
33 | 33 |
|
34 | 34 |
namespace lemon { |
35 | 35 |
|
36 | 36 |
/// \addtogroup paths |
37 | 37 |
/// @{ |
38 | 38 |
|
39 | 39 |
|
40 | 40 |
/// \brief A structure for representing directed paths in a digraph. |
41 | 41 |
/// |
42 | 42 |
/// A structure for representing directed path in a digraph. |
43 | 43 |
/// \param Digraph The digraph type in which the path is. |
44 | 44 |
/// |
45 | 45 |
/// In a sense, the path can be treated as a list of arcs. The |
46 |
/// lemon path type stores just this list. As a consequence it |
|
47 |
/// cannot enumerate the nodes in the path and the zero length paths |
|
48 |
/// |
|
46 |
/// lemon path type stores just this list. As a consequence, it |
|
47 |
/// cannot enumerate the nodes of the path and the source node of |
|
48 |
/// a zero length path is undefined. |
|
49 | 49 |
/// |
50 | 50 |
/// This implementation is a back and front insertable and erasable |
51 | 51 |
/// path type. It can be indexed in O(1) time. The front and back |
52 |
/// insertion and erasure is amortized O(1) time. The |
|
53 |
/// impelementation is based on two opposite organized vectors. |
|
52 |
/// insertion and erase is done in O(1) (amortized) time. The |
|
53 |
/// implementation uses two vectors for storing the front and back |
|
54 |
/// insertions. |
|
54 | 55 |
template <typename _Digraph> |
55 | 56 |
class Path { |
56 | 57 |
public: |
57 | 58 |
|
58 | 59 |
typedef _Digraph Digraph; |
59 | 60 |
typedef typename Digraph::Arc Arc; |
60 | 61 |
|
61 | 62 |
/// \brief Default constructor |
62 | 63 |
/// |
63 | 64 |
/// Default constructor |
64 | 65 |
Path() {} |
65 | 66 |
|
66 | 67 |
/// \brief Template copy constructor |
67 | 68 |
/// |
68 |
/// This path can be initialized with any other path type. It just |
|
69 |
/// makes a copy of the given path. |
|
69 |
/// This constuctor initializes the path from any other path type. |
|
70 |
/// It simply makes a copy of the given path. |
|
70 | 71 |
template <typename CPath> |
71 | 72 |
Path(const CPath& cpath) { |
72 | 73 |
copyPath(*this, cpath); |
73 | 74 |
} |
74 | 75 |
|
75 | 76 |
/// \brief Template copy assignment |
76 | 77 |
/// |
77 |
/// This path can be initialized with any other path type. It just |
|
78 |
/// makes a copy of the given path. |
|
78 |
/// This operator makes a copy of a path of any other type. |
|
79 | 79 |
template <typename CPath> |
80 | 80 |
Path& operator=(const CPath& cpath) { |
81 | 81 |
copyPath(*this, cpath); |
82 | 82 |
return *this; |
83 | 83 |
} |
84 | 84 |
|
85 | 85 |
/// \brief Lemon style iterator for path arcs |
86 | 86 |
/// |
87 | 87 |
/// This class is used to iterate on the arcs of the paths. |
88 | 88 |
class ArcIt { |
89 | 89 |
friend class Path; |
90 | 90 |
public: |
91 | 91 |
/// \brief Default constructor |
92 | 92 |
ArcIt() {} |
93 | 93 |
/// \brief Invalid constructor |
94 | 94 |
ArcIt(Invalid) : path(0), idx(-1) {} |
95 |
/// \brief Initializate the |
|
95 |
/// \brief Initializate the iterator to the first arc of path |
|
96 | 96 |
ArcIt(const Path &_path) |
97 | 97 |
: path(&_path), idx(_path.empty() ? -1 : 0) {} |
98 | 98 |
|
99 | 99 |
private: |
100 | 100 |
|
101 | 101 |
ArcIt(const Path &_path, int _idx) |
102 | 102 |
: path(&_path), idx(_idx) {} |
103 | 103 |
|
104 | 104 |
public: |
105 | 105 |
|
106 | 106 |
/// \brief Conversion to Arc |
107 | 107 |
operator const Arc&() const { |
108 | 108 |
return path->nth(idx); |
109 | 109 |
} |
110 | 110 |
|
111 | 111 |
/// \brief Next arc |
112 | 112 |
ArcIt& operator++() { |
113 | 113 |
++idx; |
114 | 114 |
if (idx >= path->length()) idx = -1; |
115 | 115 |
return *this; |
116 | 116 |
} |
117 | 117 |
|
118 | 118 |
/// \brief Comparison operator |
119 | 119 |
bool operator==(const ArcIt& e) const { return idx==e.idx; } |
120 | 120 |
/// \brief Comparison operator |
121 | 121 |
bool operator!=(const ArcIt& e) const { return idx!=e.idx; } |
122 | 122 |
/// \brief Comparison operator |
123 | 123 |
bool operator<(const ArcIt& e) const { return idx<e.idx; } |
124 | 124 |
|
125 | 125 |
private: |
126 | 126 |
const Path *path; |
127 | 127 |
int idx; |
128 | 128 |
}; |
129 | 129 |
|
130 | 130 |
/// \brief Length of the path. |
131 | 131 |
int length() const { return head.size() + tail.size(); } |
132 |
/// \brief |
|
132 |
/// \brief Return whether the path is empty. |
|
133 | 133 |
bool empty() const { return head.empty() && tail.empty(); } |
134 | 134 |
|
135 |
/// \brief |
|
135 |
/// \brief Reset the path to an empty one. |
|
136 | 136 |
void clear() { head.clear(); tail.clear(); } |
137 | 137 |
|
138 |
/// \brief |
|
138 |
/// \brief The nth arc. |
|
139 | 139 |
/// |
140 | 140 |
/// \pre n is in the [0..length() - 1] range |
141 | 141 |
const Arc& nth(int n) const { |
142 | 142 |
return n < int(head.size()) ? *(head.rbegin() + n) : |
143 | 143 |
*(tail.begin() + (n - head.size())); |
144 | 144 |
} |
145 | 145 |
|
146 |
/// \brief |
|
146 |
/// \brief Initialize arc iterator to point to the nth arc |
|
147 | 147 |
/// |
148 | 148 |
/// \pre n is in the [0..length() - 1] range |
149 | 149 |
ArcIt nthIt(int n) const { |
150 | 150 |
return ArcIt(*this, n); |
151 | 151 |
} |
152 | 152 |
|
153 |
/// \brief |
|
153 |
/// \brief The first arc of the path |
|
154 | 154 |
const Arc& front() const { |
155 | 155 |
return head.empty() ? tail.front() : head.back(); |
156 | 156 |
} |
157 | 157 |
|
158 | 158 |
/// \brief Add a new arc before the current path |
159 | 159 |
void addFront(const Arc& arc) { |
160 | 160 |
head.push_back(arc); |
161 | 161 |
} |
162 | 162 |
|
163 | 163 |
/// \brief Erase the first arc of the path |
164 | 164 |
void eraseFront() { |
165 | 165 |
if (!head.empty()) { |
166 | 166 |
head.pop_back(); |
167 | 167 |
} else { |
168 | 168 |
head.clear(); |
169 | 169 |
int halfsize = tail.size() / 2; |
170 | 170 |
head.resize(halfsize); |
171 | 171 |
std::copy(tail.begin() + 1, tail.begin() + halfsize + 1, |
172 | 172 |
head.rbegin()); |
173 | 173 |
std::copy(tail.begin() + halfsize + 1, tail.end(), tail.begin()); |
174 | 174 |
tail.resize(tail.size() - halfsize - 1); |
175 | 175 |
} |
176 | 176 |
} |
177 | 177 |
|
178 |
/// \brief |
|
178 |
/// \brief The last arc of the path |
|
179 | 179 |
const Arc& back() const { |
180 | 180 |
return tail.empty() ? head.front() : tail.back(); |
181 | 181 |
} |
182 | 182 |
|
183 | 183 |
/// \brief Add a new arc behind the current path |
184 | 184 |
void addBack(const Arc& arc) { |
185 | 185 |
tail.push_back(arc); |
186 | 186 |
} |
187 | 187 |
|
188 | 188 |
/// \brief Erase the last arc of the path |
189 | 189 |
void eraseBack() { |
190 | 190 |
if (!tail.empty()) { |
191 | 191 |
tail.pop_back(); |
192 | 192 |
} else { |
193 | 193 |
int halfsize = head.size() / 2; |
194 | 194 |
tail.resize(halfsize); |
195 | 195 |
std::copy(head.begin() + 1, head.begin() + halfsize + 1, |
196 | 196 |
tail.rbegin()); |
197 | 197 |
std::copy(head.begin() + halfsize + 1, head.end(), head.begin()); |
198 | 198 |
head.resize(head.size() - halfsize - 1); |
199 | 199 |
} |
200 | 200 |
} |
201 | 201 |
|
202 |
|
|
203 |
|
|
204 | 202 |
typedef True BuildTag; |
205 | 203 |
|
206 | 204 |
template <typename CPath> |
207 | 205 |
void build(const CPath& path) { |
208 | 206 |
int len = path.length(); |
209 | 207 |
tail.reserve(len); |
210 | 208 |
for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
211 | 209 |
tail.push_back(it); |
212 | 210 |
} |
213 | 211 |
} |
214 | 212 |
|
215 | 213 |
template <typename CPath> |
216 | 214 |
void buildRev(const CPath& path) { |
217 | 215 |
int len = path.length(); |
218 | 216 |
head.reserve(len); |
219 | 217 |
for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
220 | 218 |
head.push_back(it); |
221 | 219 |
} |
222 | 220 |
} |
223 | 221 |
|
224 | 222 |
protected: |
225 | 223 |
typedef std::vector<Arc> Container; |
226 | 224 |
Container head, tail; |
227 | 225 |
|
228 | 226 |
}; |
229 | 227 |
|
230 | 228 |
/// \brief A structure for representing directed paths in a digraph. |
231 | 229 |
/// |
232 | 230 |
/// A structure for representing directed path in a digraph. |
233 | 231 |
/// \param Digraph The digraph type in which the path is. |
234 | 232 |
/// |
235 | 233 |
/// In a sense, the path can be treated as a list of arcs. The |
236 | 234 |
/// lemon path type stores just this list. As a consequence it |
237 | 235 |
/// cannot enumerate the nodes in the path and the zero length paths |
238 | 236 |
/// cannot store the source. |
239 | 237 |
/// |
240 | 238 |
/// This implementation is a just back insertable and erasable path |
241 | 239 |
/// type. It can be indexed in O(1) time. The back insertion and |
242 | 240 |
/// erasure is amortized O(1) time. This implementation is faster |
243 | 241 |
/// then the \c Path type because it use just one vector for the |
244 | 242 |
/// arcs. |
245 | 243 |
template <typename _Digraph> |
246 | 244 |
class SimplePath { |
247 | 245 |
public: |
248 | 246 |
|
249 | 247 |
typedef _Digraph Digraph; |
250 | 248 |
typedef typename Digraph::Arc Arc; |
251 | 249 |
|
252 | 250 |
/// \brief Default constructor |
253 | 251 |
/// |
254 | 252 |
/// Default constructor |
255 | 253 |
SimplePath() {} |
256 | 254 |
|
257 | 255 |
/// \brief Template copy constructor |
258 | 256 |
/// |
259 | 257 |
/// This path can be initialized with any other path type. It just |
260 | 258 |
/// makes a copy of the given path. |
261 | 259 |
template <typename CPath> |
262 | 260 |
SimplePath(const CPath& cpath) { |
263 | 261 |
copyPath(*this, cpath); |
264 | 262 |
} |
265 | 263 |
|
266 | 264 |
/// \brief Template copy assignment |
267 | 265 |
/// |
268 | 266 |
/// This path can be initialized with any other path type. It just |
269 | 267 |
/// makes a copy of the given path. |
270 | 268 |
template <typename CPath> |
271 | 269 |
SimplePath& operator=(const CPath& cpath) { |
272 | 270 |
copyPath(*this, cpath); |
273 | 271 |
return *this; |
274 | 272 |
} |
275 | 273 |
|
276 | 274 |
/// \brief Iterator class to iterate on the arcs of the paths |
277 | 275 |
/// |
278 | 276 |
/// This class is used to iterate on the arcs of the paths |
279 | 277 |
/// |
280 | 278 |
/// Of course it converts to Digraph::Arc |
281 | 279 |
class ArcIt { |
282 | 280 |
friend class SimplePath; |
283 | 281 |
public: |
284 | 282 |
/// Default constructor |
285 | 283 |
ArcIt() {} |
286 | 284 |
/// Invalid constructor |
287 | 285 |
ArcIt(Invalid) : path(0), idx(-1) {} |
288 | 286 |
/// \brief Initializate the constructor to the first arc of path |
289 | 287 |
ArcIt(const SimplePath &_path) |
290 | 288 |
: path(&_path), idx(_path.empty() ? -1 : 0) {} |
291 | 289 |
|
292 | 290 |
private: |
293 | 291 |
|
294 | 292 |
/// Constructor with starting point |
295 | 293 |
ArcIt(const SimplePath &_path, int _idx) |
296 | 294 |
: idx(_idx), path(&_path) {} |
297 | 295 |
|
298 | 296 |
public: |
299 | 297 |
|
300 | 298 |
///Conversion to Digraph::Arc |
301 | 299 |
operator const Arc&() const { |
302 | 300 |
return path->nth(idx); |
303 | 301 |
} |
304 | 302 |
|
305 | 303 |
/// Next arc |
306 | 304 |
ArcIt& operator++() { |
307 | 305 |
++idx; |
308 | 306 |
if (idx >= path->length()) idx = -1; |
309 | 307 |
return *this; |
310 | 308 |
} |
311 | 309 |
|
312 | 310 |
/// Comparison operator |
313 | 311 |
bool operator==(const ArcIt& e) const { return idx==e.idx; } |
314 | 312 |
/// Comparison operator |
315 | 313 |
bool operator!=(const ArcIt& e) const { return idx!=e.idx; } |
316 | 314 |
/// Comparison operator |
317 | 315 |
bool operator<(const ArcIt& e) const { return idx<e.idx; } |
318 | 316 |
|
319 | 317 |
private: |
320 | 318 |
const SimplePath *path; |
321 | 319 |
int idx; |
322 | 320 |
}; |
323 | 321 |
|
324 | 322 |
/// \brief Length of the path. |
325 | 323 |
int length() const { return data.size(); } |
326 |
/// \brief |
|
324 |
/// \brief Return true if the path is empty. |
|
327 | 325 |
bool empty() const { return data.empty(); } |
328 | 326 |
|
329 |
/// \brief |
|
327 |
/// \brief Reset the path to an empty one. |
|
330 | 328 |
void clear() { data.clear(); } |
331 | 329 |
|
332 |
/// \brief |
|
330 |
/// \brief The nth arc. |
|
333 | 331 |
/// |
334 | 332 |
/// \pre n is in the [0..length() - 1] range |
335 | 333 |
const Arc& nth(int n) const { |
336 | 334 |
return data[n]; |
337 | 335 |
} |
338 | 336 |
|
339 | 337 |
/// \brief Initializes arc iterator to point to the nth arc. |
340 | 338 |
ArcIt nthIt(int n) const { |
341 | 339 |
return ArcIt(*this, n); |
342 | 340 |
} |
343 | 341 |
|
344 |
/// \brief |
|
342 |
/// \brief The first arc of the path. |
|
345 | 343 |
const Arc& front() const { |
346 | 344 |
return data.front(); |
347 | 345 |
} |
348 | 346 |
|
349 |
/// \brief |
|
347 |
/// \brief The last arc of the path. |
|
350 | 348 |
const Arc& back() const { |
351 | 349 |
return data.back(); |
352 | 350 |
} |
353 | 351 |
|
354 | 352 |
/// \brief Add a new arc behind the current path. |
355 | 353 |
void addBack(const Arc& arc) { |
356 | 354 |
data.push_back(arc); |
357 | 355 |
} |
358 | 356 |
|
359 | 357 |
/// \brief Erase the last arc of the path |
360 | 358 |
void eraseBack() { |
361 | 359 |
data.pop_back(); |
362 | 360 |
} |
363 | 361 |
|
364 | 362 |
typedef True BuildTag; |
365 | 363 |
|
366 | 364 |
template <typename CPath> |
367 | 365 |
void build(const CPath& path) { |
368 | 366 |
int len = path.length(); |
369 | 367 |
data.resize(len); |
370 | 368 |
int index = 0; |
371 | 369 |
for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
372 | 370 |
data[index] = it;; |
373 | 371 |
++index; |
374 | 372 |
} |
375 | 373 |
} |
376 | 374 |
|
377 | 375 |
template <typename CPath> |
378 | 376 |
void buildRev(const CPath& path) { |
379 | 377 |
int len = path.length(); |
380 | 378 |
data.resize(len); |
381 | 379 |
int index = len; |
382 | 380 |
for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
383 | 381 |
--index; |
384 | 382 |
data[index] = it;; |
385 | 383 |
} |
386 | 384 |
} |
387 | 385 |
|
388 | 386 |
protected: |
389 | 387 |
typedef std::vector<Arc> Container; |
390 | 388 |
Container data; |
391 | 389 |
|
392 | 390 |
}; |
393 | 391 |
|
394 | 392 |
/// \brief A structure for representing directed paths in a digraph. |
395 | 393 |
/// |
396 | 394 |
/// A structure for representing directed path in a digraph. |
397 | 395 |
/// \param Digraph The digraph type in which the path is. |
398 | 396 |
/// |
399 | 397 |
/// In a sense, the path can be treated as a list of arcs. The |
400 | 398 |
/// lemon path type stores just this list. As a consequence it |
401 | 399 |
/// cannot enumerate the nodes in the path and the zero length paths |
402 | 400 |
/// cannot store the source. |
403 | 401 |
/// |
404 | 402 |
/// This implementation is a back and front insertable and erasable |
405 | 403 |
/// path type. It can be indexed in O(k) time, where k is the rank |
406 | 404 |
/// of the arc in the path. The length can be computed in O(n) |
407 | 405 |
/// time. The front and back insertion and erasure is O(1) time |
408 | 406 |
/// and it can be splited and spliced in O(1) time. |
409 | 407 |
template <typename _Digraph> |
410 | 408 |
class ListPath { |
411 | 409 |
public: |
412 | 410 |
|
413 | 411 |
typedef _Digraph Digraph; |
414 | 412 |
typedef typename Digraph::Arc Arc; |
415 | 413 |
|
416 | 414 |
protected: |
417 | 415 |
|
418 | 416 |
// the std::list<> is incompatible |
419 | 417 |
// hard to create invalid iterator |
420 | 418 |
struct Node { |
421 | 419 |
Arc arc; |
422 | 420 |
Node *next, *prev; |
423 | 421 |
}; |
424 | 422 |
|
425 | 423 |
Node *first, *last; |
426 | 424 |
|
427 | 425 |
std::allocator<Node> alloc; |
428 | 426 |
|
429 | 427 |
public: |
430 | 428 |
|
431 | 429 |
/// \brief Default constructor |
432 | 430 |
/// |
433 | 431 |
/// Default constructor |
434 | 432 |
ListPath() : first(0), last(0) {} |
435 | 433 |
|
436 | 434 |
/// \brief Template copy constructor |
437 | 435 |
/// |
438 | 436 |
/// This path can be initialized with any other path type. It just |
439 | 437 |
/// makes a copy of the given path. |
440 | 438 |
template <typename CPath> |
441 | 439 |
ListPath(const CPath& cpath) : first(0), last(0) { |
442 | 440 |
copyPath(*this, cpath); |
443 | 441 |
} |
444 | 442 |
|
445 | 443 |
/// \brief Destructor of the path |
446 | 444 |
/// |
447 | 445 |
/// Destructor of the path |
448 | 446 |
~ListPath() { |
449 | 447 |
clear(); |
450 | 448 |
} |
451 | 449 |
|
452 | 450 |
/// \brief Template copy assignment |
453 | 451 |
/// |
454 | 452 |
/// This path can be initialized with any other path type. It just |
455 | 453 |
/// makes a copy of the given path. |
456 | 454 |
template <typename CPath> |
457 | 455 |
ListPath& operator=(const CPath& cpath) { |
458 | 456 |
copyPath(*this, cpath); |
459 | 457 |
return *this; |
460 | 458 |
} |
461 | 459 |
|
462 | 460 |
/// \brief Iterator class to iterate on the arcs of the paths |
463 | 461 |
/// |
464 | 462 |
/// This class is used to iterate on the arcs of the paths |
465 | 463 |
/// |
466 | 464 |
/// Of course it converts to Digraph::Arc |
467 | 465 |
class ArcIt { |
468 | 466 |
friend class ListPath; |
469 | 467 |
public: |
470 | 468 |
/// Default constructor |
471 | 469 |
ArcIt() {} |
472 | 470 |
/// Invalid constructor |
473 | 471 |
ArcIt(Invalid) : path(0), node(0) {} |
474 | 472 |
/// \brief Initializate the constructor to the first arc of path |
475 | 473 |
ArcIt(const ListPath &_path) |
476 | 474 |
: path(&_path), node(_path.first) {} |
477 | 475 |
|
478 | 476 |
protected: |
479 | 477 |
|
480 | 478 |
ArcIt(const ListPath &_path, Node *_node) |
481 | 479 |
: path(&_path), node(_node) {} |
482 | 480 |
|
483 | 481 |
|
484 | 482 |
public: |
485 | 483 |
|
486 | 484 |
///Conversion to Digraph::Arc |
487 | 485 |
operator const Arc&() const { |
488 | 486 |
return node->arc; |
489 | 487 |
} |
490 | 488 |
|
491 | 489 |
/// Next arc |
492 | 490 |
ArcIt& operator++() { |
493 | 491 |
node = node->next; |
494 | 492 |
return *this; |
495 | 493 |
} |
496 | 494 |
|
497 | 495 |
/// Comparison operator |
498 | 496 |
bool operator==(const ArcIt& e) const { return node==e.node; } |
499 | 497 |
/// Comparison operator |
500 | 498 |
bool operator!=(const ArcIt& e) const { return node!=e.node; } |
501 | 499 |
/// Comparison operator |
502 | 500 |
bool operator<(const ArcIt& e) const { return node<e.node; } |
503 | 501 |
|
504 | 502 |
private: |
505 | 503 |
const ListPath *path; |
506 | 504 |
Node *node; |
507 | 505 |
}; |
508 | 506 |
|
509 |
/// \brief |
|
507 |
/// \brief The nth arc. |
|
510 | 508 |
/// |
511 |
/// |
|
509 |
/// This function looks for the nth arc in O(n) time. |
|
512 | 510 |
/// \pre n is in the [0..length() - 1] range |
513 | 511 |
const Arc& nth(int n) const { |
514 | 512 |
Node *node = first; |
515 | 513 |
for (int i = 0; i < n; ++i) { |
516 | 514 |
node = node->next; |
517 | 515 |
} |
518 | 516 |
return node->arc; |
519 | 517 |
} |
520 | 518 |
|
521 | 519 |
/// \brief Initializes arc iterator to point to the nth arc. |
522 | 520 |
ArcIt nthIt(int n) const { |
523 | 521 |
Node *node = first; |
524 | 522 |
for (int i = 0; i < n; ++i) { |
525 | 523 |
node = node->next; |
526 | 524 |
} |
527 | 525 |
return ArcIt(*this, node); |
528 | 526 |
} |
529 | 527 |
|
530 | 528 |
/// \brief Length of the path. |
531 | 529 |
int length() const { |
532 | 530 |
int len = 0; |
533 | 531 |
Node *node = first; |
534 | 532 |
while (node != 0) { |
535 | 533 |
node = node->next; |
536 | 534 |
++len; |
537 | 535 |
} |
538 | 536 |
return len; |
539 | 537 |
} |
540 | 538 |
|
541 |
/// \brief |
|
539 |
/// \brief Return true if the path is empty. |
|
542 | 540 |
bool empty() const { return first == 0; } |
543 | 541 |
|
544 |
/// \brief |
|
542 |
/// \brief Reset the path to an empty one. |
|
545 | 543 |
void clear() { |
546 | 544 |
while (first != 0) { |
547 | 545 |
last = first->next; |
548 | 546 |
alloc.destroy(first); |
549 | 547 |
alloc.deallocate(first, 1); |
550 | 548 |
first = last; |
551 | 549 |
} |
552 | 550 |
} |
553 | 551 |
|
554 |
/// \brief |
|
552 |
/// \brief The first arc of the path |
|
555 | 553 |
const Arc& front() const { |
556 | 554 |
return first->arc; |
557 | 555 |
} |
558 | 556 |
|
559 | 557 |
/// \brief Add a new arc before the current path |
560 | 558 |
void addFront(const Arc& arc) { |
561 | 559 |
Node *node = alloc.allocate(1); |
562 | 560 |
alloc.construct(node, Node()); |
563 | 561 |
node->prev = 0; |
564 | 562 |
node->next = first; |
565 | 563 |
node->arc = arc; |
566 | 564 |
if (first) { |
567 | 565 |
first->prev = node; |
568 | 566 |
first = node; |
569 | 567 |
} else { |
570 | 568 |
first = last = node; |
571 | 569 |
} |
572 | 570 |
} |
573 | 571 |
|
574 | 572 |
/// \brief Erase the first arc of the path |
575 | 573 |
void eraseFront() { |
576 | 574 |
Node *node = first; |
577 | 575 |
first = first->next; |
578 | 576 |
if (first) { |
579 | 577 |
first->prev = 0; |
580 | 578 |
} else { |
581 | 579 |
last = 0; |
582 | 580 |
} |
583 | 581 |
alloc.destroy(node); |
584 | 582 |
alloc.deallocate(node, 1); |
585 | 583 |
} |
586 | 584 |
|
587 |
/// \brief |
|
585 |
/// \brief The last arc of the path. |
|
588 | 586 |
const Arc& back() const { |
589 | 587 |
return last->arc; |
590 | 588 |
} |
591 | 589 |
|
592 | 590 |
/// \brief Add a new arc behind the current path. |
593 | 591 |
void addBack(const Arc& arc) { |
594 | 592 |
Node *node = alloc.allocate(1); |
595 | 593 |
alloc.construct(node, Node()); |
596 | 594 |
node->next = 0; |
597 | 595 |
node->prev = last; |
598 | 596 |
node->arc = arc; |
599 | 597 |
if (last) { |
600 | 598 |
last->next = node; |
601 | 599 |
last = node; |
602 | 600 |
} else { |
603 | 601 |
last = first = node; |
604 | 602 |
} |
605 | 603 |
} |
606 | 604 |
|
607 | 605 |
/// \brief Erase the last arc of the path |
608 | 606 |
void eraseBack() { |
609 | 607 |
Node *node = last; |
610 | 608 |
last = last->prev; |
611 | 609 |
if (last) { |
612 | 610 |
last->next = 0; |
613 | 611 |
} else { |
614 | 612 |
first = 0; |
615 | 613 |
} |
616 | 614 |
alloc.destroy(node); |
617 | 615 |
alloc.deallocate(node, 1); |
618 | 616 |
} |
619 | 617 |
|
620 |
/// \brief |
|
618 |
/// \brief Splice a path to the back of the current path. |
|
621 | 619 |
/// |
622 |
/// It splices |
|
620 |
/// It splices \c tpath to the back of the current path and \c |
|
623 | 621 |
/// tpath becomes empty. The time complexity of this function is |
624 | 622 |
/// O(1). |
625 | 623 |
void spliceBack(ListPath& tpath) { |
626 | 624 |
if (first) { |
627 | 625 |
if (tpath.first) { |
628 | 626 |
last->next = tpath.first; |
629 | 627 |
tpath.first->prev = last; |
630 | 628 |
last = tpath.last; |
631 | 629 |
} |
632 | 630 |
} else { |
633 | 631 |
first = tpath.first; |
634 | 632 |
last = tpath.last; |
635 | 633 |
} |
636 | 634 |
tpath.first = tpath.last = 0; |
637 | 635 |
} |
638 | 636 |
|
639 |
/// \brief |
|
637 |
/// \brief Splice a path to the front of the current path. |
|
640 | 638 |
/// |
641 |
/// It splices |
|
639 |
/// It splices \c tpath before the current path and \c tpath |
|
642 | 640 |
/// becomes empty. The time complexity of this function |
643 | 641 |
/// is O(1). |
644 | 642 |
void spliceFront(ListPath& tpath) { |
645 | 643 |
if (first) { |
646 | 644 |
if (tpath.first) { |
647 | 645 |
first->prev = tpath.last; |
648 | 646 |
tpath.last->next = first; |
649 | 647 |
first = tpath.first; |
650 | 648 |
} |
651 | 649 |
} else { |
652 | 650 |
first = tpath.first; |
653 | 651 |
last = tpath.last; |
654 | 652 |
} |
655 | 653 |
tpath.first = tpath.last = 0; |
656 | 654 |
} |
657 | 655 |
|
658 |
/// \brief |
|
656 |
/// \brief Splice a path into the current path. |
|
659 | 657 |
/// |
660 | 658 |
/// It splices the \c tpath into the current path before the |
661 | 659 |
/// position of \c it iterator and \c tpath becomes empty. The |
662 |
/// time complexity of this function is O(1). If the \c it is \c |
|
663 |
/// INVALID then it will splice behind the current path. |
|
660 |
/// time complexity of this function is O(1). If the \c it is |
|
661 |
/// \c INVALID then it will splice behind the current path. |
|
664 | 662 |
void splice(ArcIt it, ListPath& tpath) { |
665 | 663 |
if (it.node) { |
666 | 664 |
if (tpath.first) { |
667 | 665 |
tpath.first->prev = it.node->prev; |
668 | 666 |
if (it.node->prev) { |
669 | 667 |
it.node->prev->next = tpath.first; |
670 | 668 |
} else { |
671 | 669 |
first = tpath.first; |
672 | 670 |
} |
673 | 671 |
it.node->prev = tpath.last; |
674 | 672 |
tpath.last->next = it.node; |
675 | 673 |
} |
676 | 674 |
} else { |
677 | 675 |
if (first) { |
678 | 676 |
if (tpath.first) { |
679 | 677 |
last->next = tpath.first; |
680 | 678 |
tpath.first->prev = last; |
681 | 679 |
last = tpath.last; |
682 | 680 |
} |
683 | 681 |
} else { |
684 | 682 |
first = tpath.first; |
685 | 683 |
last = tpath.last; |
686 | 684 |
} |
687 | 685 |
} |
688 | 686 |
tpath.first = tpath.last = 0; |
689 | 687 |
} |
690 | 688 |
|
691 |
/// \brief |
|
689 |
/// \brief Split the current path. |
|
692 | 690 |
/// |
693 |
/// It splits the current path into two parts. The part before \c |
|
694 |
/// it iterator will remain in the current path and the part from |
|
695 |
/// the it will put into the \c tpath. If the \c tpath had arcs |
|
696 |
/// before the operation they will be removed first. The time |
|
697 |
/// complexity of this function is O(1) plus the clearing of \c |
|
698 |
/// tpath. If the \c it is \c INVALID then it just clears \c |
|
699 |
/// |
|
691 |
/// It splits the current path into two parts. The part before |
|
692 |
/// the iterator \c it will remain in the current path and the part |
|
693 |
/// starting with |
|
694 |
/// \c it will put into \c tpath. If \c tpath have arcs |
|
695 |
/// before the operation they are removed first. The time |
|
696 |
/// complexity of this function is O(1) plus the the time of emtying |
|
697 |
/// \c tpath. If \c it is \c INVALID then it just clears \c tpath |
|
700 | 698 |
void split(ArcIt it, ListPath& tpath) { |
701 | 699 |
tpath.clear(); |
702 | 700 |
if (it.node) { |
703 | 701 |
tpath.first = it.node; |
704 | 702 |
tpath.last = last; |
705 | 703 |
if (it.node->prev) { |
706 | 704 |
last = it.node->prev; |
707 | 705 |
last->next = 0; |
708 | 706 |
} else { |
709 | 707 |
first = last = 0; |
710 | 708 |
} |
711 | 709 |
it.node->prev = 0; |
712 | 710 |
} |
713 | 711 |
} |
714 | 712 |
|
715 | 713 |
|
716 | 714 |
typedef True BuildTag; |
717 | 715 |
|
718 | 716 |
template <typename CPath> |
719 | 717 |
void build(const CPath& path) { |
720 | 718 |
for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
721 | 719 |
addBack(it); |
722 | 720 |
} |
723 | 721 |
} |
724 | 722 |
|
725 | 723 |
template <typename CPath> |
726 | 724 |
void buildRev(const CPath& path) { |
727 | 725 |
for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
728 | 726 |
addFront(it); |
729 | 727 |
} |
730 | 728 |
} |
731 | 729 |
|
732 | 730 |
}; |
733 | 731 |
|
734 | 732 |
/// \brief A structure for representing directed paths in a digraph. |
735 | 733 |
/// |
736 | 734 |
/// A structure for representing directed path in a digraph. |
737 | 735 |
/// \param Digraph The digraph type in which the path is. |
738 | 736 |
/// |
739 | 737 |
/// In a sense, the path can be treated as a list of arcs. The |
740 | 738 |
/// lemon path type stores just this list. As a consequence it |
741 |
/// cannot enumerate the nodes in the path and the zero length paths |
|
742 |
/// cannot store the source. |
|
739 |
/// cannot enumerate the nodes in the path and the source node of |
|
740 |
/// a zero length path is undefined. |
|
743 | 741 |
/// |
744 |
/// This implementation is completly static, so it cannot be |
|
745 |
/// modified exclude the assign an other path. It is intented to be |
|
746 |
/// used when you want to store a large number of paths because it is |
|
747 |
/// the most memory efficient path type in the lemon. |
|
742 |
/// This implementation is completly static, i.e. it can be copy constucted |
|
743 |
/// or copy assigned from another path, but otherwise it cannot be |
|
744 |
/// modified. |
|
745 |
/// |
|
746 |
/// Being the the most memory efficient path type in LEMON, |
|
747 |
/// it is intented to be |
|
748 |
/// used when you want to store a large number of paths. |
|
748 | 749 |
template <typename _Digraph> |
749 | 750 |
class StaticPath { |
750 | 751 |
public: |
751 | 752 |
|
752 | 753 |
typedef _Digraph Digraph; |
753 | 754 |
typedef typename Digraph::Arc Arc; |
754 | 755 |
|
755 | 756 |
/// \brief Default constructor |
756 | 757 |
/// |
757 | 758 |
/// Default constructor |
758 | 759 |
StaticPath() : len(0), arcs(0) {} |
759 | 760 |
|
760 | 761 |
/// \brief Template copy constructor |
761 | 762 |
/// |
762 |
/// This path can be initialized with any other path type. It just |
|
763 |
/// makes a copy of the given path. |
|
763 |
/// This path can be initialized from any other path type. |
|
764 | 764 |
template <typename CPath> |
765 | 765 |
StaticPath(const CPath& cpath) : arcs(0) { |
766 | 766 |
copyPath(*this, cpath); |
767 | 767 |
} |
768 | 768 |
|
769 | 769 |
/// \brief Destructor of the path |
770 | 770 |
/// |
771 | 771 |
/// Destructor of the path |
772 | 772 |
~StaticPath() { |
773 | 773 |
if (arcs) delete[] arcs; |
774 | 774 |
} |
775 | 775 |
|
776 | 776 |
/// \brief Template copy assignment |
777 | 777 |
/// |
778 |
/// This path can be |
|
778 |
/// This path can be made equal to any other path type. It simply |
|
779 | 779 |
/// makes a copy of the given path. |
780 | 780 |
template <typename CPath> |
781 | 781 |
StaticPath& operator=(const CPath& cpath) { |
782 | 782 |
copyPath(*this, cpath); |
783 | 783 |
return *this; |
784 | 784 |
} |
785 | 785 |
|
786 | 786 |
/// \brief Iterator class to iterate on the arcs of the paths |
787 | 787 |
/// |
788 | 788 |
/// This class is used to iterate on the arcs of the paths |
789 | 789 |
/// |
790 | 790 |
/// Of course it converts to Digraph::Arc |
791 | 791 |
class ArcIt { |
792 | 792 |
friend class StaticPath; |
793 | 793 |
public: |
794 | 794 |
/// Default constructor |
795 | 795 |
ArcIt() {} |
796 | 796 |
/// Invalid constructor |
797 | 797 |
ArcIt(Invalid) : path(0), idx(-1) {} |
798 | 798 |
/// Initializate the constructor to the first arc of path |
799 | 799 |
ArcIt(const StaticPath &_path) |
800 | 800 |
: path(&_path), idx(_path.empty() ? -1 : 0) {} |
801 | 801 |
|
802 | 802 |
private: |
803 | 803 |
|
804 | 804 |
/// Constructor with starting point |
805 | 805 |
ArcIt(const StaticPath &_path, int _idx) |
806 | 806 |
: idx(_idx), path(&_path) {} |
807 | 807 |
|
808 | 808 |
public: |
809 | 809 |
|
810 | 810 |
///Conversion to Digraph::Arc |
811 | 811 |
operator const Arc&() const { |
812 | 812 |
return path->nth(idx); |
813 | 813 |
} |
814 | 814 |
|
815 | 815 |
/// Next arc |
816 | 816 |
ArcIt& operator++() { |
817 | 817 |
++idx; |
818 | 818 |
if (idx >= path->length()) idx = -1; |
819 | 819 |
return *this; |
820 | 820 |
} |
821 | 821 |
|
822 | 822 |
/// Comparison operator |
823 | 823 |
bool operator==(const ArcIt& e) const { return idx==e.idx; } |
824 | 824 |
/// Comparison operator |
825 | 825 |
bool operator!=(const ArcIt& e) const { return idx!=e.idx; } |
826 | 826 |
/// Comparison operator |
827 | 827 |
bool operator<(const ArcIt& e) const { return idx<e.idx; } |
828 | 828 |
|
829 | 829 |
private: |
830 | 830 |
const StaticPath *path; |
831 | 831 |
int idx; |
832 | 832 |
}; |
833 | 833 |
|
834 |
/// \brief |
|
834 |
/// \brief The nth arc. |
|
835 | 835 |
/// |
836 | 836 |
/// \pre n is in the [0..length() - 1] range |
837 | 837 |
const Arc& nth(int n) const { |
838 | 838 |
return arcs[n]; |
839 | 839 |
} |
840 | 840 |
|
841 |
/// \brief |
|
841 |
/// \brief The arc iterator pointing to the nth arc. |
|
842 | 842 |
ArcIt nthIt(int n) const { |
843 | 843 |
return ArcIt(*this, n); |
844 | 844 |
} |
845 | 845 |
|
846 |
/// \brief |
|
846 |
/// \brief The length of the path. |
|
847 | 847 |
int length() const { return len; } |
848 | 848 |
|
849 |
/// \brief |
|
849 |
/// \brief Return true when the path is empty. |
|
850 | 850 |
int empty() const { return len == 0; } |
851 | 851 |
|
852 |
/// \break Erase all |
|
852 |
/// \break Erase all arcs in the digraph. |
|
853 | 853 |
void clear() { |
854 | 854 |
len = 0; |
855 | 855 |
if (arcs) delete[] arcs; |
856 | 856 |
arcs = 0; |
857 | 857 |
} |
858 | 858 |
|
859 |
/// \brief |
|
859 |
/// \brief The first arc of the path. |
|
860 | 860 |
const Arc& front() const { |
861 | 861 |
return arcs[0]; |
862 | 862 |
} |
863 | 863 |
|
864 |
/// \brief |
|
864 |
/// \brief The last arc of the path. |
|
865 | 865 |
const Arc& back() const { |
866 | 866 |
return arcs[len - 1]; |
867 | 867 |
} |
868 | 868 |
|
869 | 869 |
|
870 | 870 |
typedef True BuildTag; |
871 | 871 |
|
872 | 872 |
template <typename CPath> |
873 | 873 |
void build(const CPath& path) { |
874 | 874 |
len = path.length(); |
875 | 875 |
arcs = new Arc[len]; |
876 | 876 |
int index = 0; |
877 | 877 |
for (typename CPath::ArcIt it(path); it != INVALID; ++it) { |
878 | 878 |
arcs[index] = it; |
879 | 879 |
++index; |
880 | 880 |
} |
881 | 881 |
} |
882 | 882 |
|
883 | 883 |
template <typename CPath> |
884 | 884 |
void buildRev(const CPath& path) { |
885 | 885 |
len = path.length(); |
886 | 886 |
arcs = new Arc[len]; |
887 | 887 |
int index = len; |
888 | 888 |
for (typename CPath::RevArcIt it(path); it != INVALID; ++it) { |
889 | 889 |
--index; |
890 | 890 |
arcs[index] = it; |
891 | 891 |
} |
892 | 892 |
} |
893 | 893 |
|
894 | 894 |
private: |
895 | 895 |
int len; |
896 | 896 |
Arc* arcs; |
897 | 897 |
}; |
898 | 898 |
|
899 | 899 |
///@} |
900 | 900 |
|
901 | 901 |
} // namespace lemon |
902 | 902 |
|
903 | 903 |
#endif // LEMON_PATH_H |
1 | 1 |
/* -*- C++ -*- |
2 | 2 |
* |
3 | 3 |
* This file is a part of LEMON, a generic C++ optimization library |
4 | 4 |
* |
5 | 5 |
* Copyright (C) 2003-2008 |
6 | 6 |
* Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
7 | 7 |
* (Egervary Research Group on Combinatorial Optimization, EGRES). |
8 | 8 |
* |
9 | 9 |
* Permission to use, modify and distribute this software is granted |
10 | 10 |
* provided that this copyright notice appears in all copies. For |
11 | 11 |
* precise terms see the accompanying LICENSE file. |
12 | 12 |
* |
13 | 13 |
* This software is provided "AS IS" with no warranty of any kind, |
14 | 14 |
* express or implied, and with no claim as to its suitability for any |
15 | 15 |
* purpose. |
16 | 16 |
* |
17 | 17 |
*/ |
18 | 18 |
|
19 | 19 |
///\ingroup paths |
20 | 20 |
///\file |
21 | 21 |
///\brief Classes for representing paths in digraphs. |
22 | 22 |
/// |
23 | 23 |
|
24 | 24 |
#ifndef LEMON_PATH_UTILS_H |
25 | 25 |
#define LEMON_PATH_UTILS_H |
26 | 26 |
|
27 | 27 |
#include <lemon/concepts/path.h> |
28 | 28 |
|
29 | 29 |
namespace lemon { |
30 | 30 |
|
31 | 31 |
namespace _path_bits { |
32 | 32 |
|
33 | 33 |
template <typename Path, typename Enable = void> |
34 | 34 |
struct RevTagIndicator { |
35 | 35 |
static const bool value = false; |
36 | 36 |
}; |
37 | 37 |
|
38 | 38 |
template <typename Digraph> |
39 | 39 |
struct RevTagIndicator< |
40 | 40 |
Digraph, |
41 | 41 |
typename enable_if<typename Digraph::RevTag, void>::type |
42 | 42 |
> { |
43 | 43 |
static const bool value = true; |
44 | 44 |
}; |
45 | 45 |
|
46 | 46 |
template <typename Target, typename Source, |
47 | 47 |
typename BuildEnable = void, typename RevEnable = void> |
48 | 48 |
struct PathCopySelector { |
49 | 49 |
static void copy(Target& target, const Source& source) { |
50 | 50 |
target.clear(); |
51 | 51 |
for (typename Source::ArcIt it(source); it != INVALID; ++it) { |
52 | 52 |
target.addBack(it); |
53 | 53 |
} |
54 | 54 |
} |
55 | 55 |
}; |
56 | 56 |
|
57 | 57 |
template <typename Target, typename Source, typename BuildEnable> |
58 | 58 |
struct PathCopySelector< |
59 | 59 |
Target, Source, BuildEnable, |
60 | 60 |
typename enable_if<typename Source::RevPathTag, void>::type> { |
61 | 61 |
static void copy(Target& target, const Source& source) { |
62 | 62 |
target.clear(); |
63 | 63 |
for (typename Source::RevArcIt it(source); it != INVALID; ++it) { |
64 | 64 |
target.addFront(it); |
65 | 65 |
} |
66 | 66 |
} |
67 | 67 |
}; |
68 | 68 |
|
69 | 69 |
template <typename Target, typename Source, typename RevEnable> |
70 | 70 |
struct PathCopySelector< |
71 | 71 |
Target, Source, |
72 | 72 |
typename enable_if<typename Target::BuildTag, void>::type, RevEnable> { |
73 | 73 |
static void copy(Target& target, const Source& source) { |
74 | 74 |
target.clear(); |
75 | 75 |
target.build(source); |
76 | 76 |
} |
77 | 77 |
}; |
78 | 78 |
|
79 | 79 |
template <typename Target, typename Source> |
80 | 80 |
struct PathCopySelector< |
81 | 81 |
Target, Source, |
82 | 82 |
typename enable_if<typename Target::BuildTag, void>::type, |
83 | 83 |
typename enable_if<typename Source::RevPathTag, void>::type> { |
84 | 84 |
static void copy(Target& target, const Source& source) { |
85 | 85 |
target.clear(); |
86 | 86 |
target.buildRev(source); |
87 | 87 |
} |
88 | 88 |
}; |
89 | 89 |
|
90 | 90 |
} |
91 | 91 |
|
92 | 92 |
|
93 |
/// \brief Make |
|
93 |
/// \brief Make a copy of a path. |
|
94 | 94 |
/// |
95 |
/// |
|
95 |
/// This function makes a copy of a path. |
|
96 | 96 |
template <typename Target, typename Source> |
97 | 97 |
void copyPath(Target& target, const Source& source) { |
98 | 98 |
checkConcept<concepts::PathDumper<typename Source::Digraph>, Source>(); |
99 | 99 |
_path_bits::PathCopySelector<Target, Source>::copy(target, source); |
100 | 100 |
} |
101 | 101 |
|
102 |
/// \brief |
|
102 |
/// \brief Check the consistency of a path. |
|
103 | 103 |
/// |
104 |
/// |
|
104 |
/// This function checks that the target of each arc is the same |
|
105 |
/// as the source of the next one. |
|
105 | 106 |
/// |
106 | 107 |
template <typename Digraph, typename Path> |
107 | 108 |
bool checkPath(const Digraph& digraph, const Path& path) { |
108 | 109 |
typename Path::ArcIt it(path); |
109 | 110 |
if (it == INVALID) return true; |
110 | 111 |
typename Digraph::Node node = digraph.target(it); |
111 | 112 |
++it; |
112 | 113 |
while (it != INVALID) { |
113 | 114 |
if (digraph.source(it) != node) return false; |
114 | 115 |
node = digraph.target(it); |
115 | 116 |
++it; |
116 | 117 |
} |
117 | 118 |
return true; |
118 | 119 |
} |
119 | 120 |
|
120 |
/// \brief |
|
121 |
/// \brief The source of a path |
|
121 | 122 |
/// |
122 |
/// |
|
123 |
/// This function returns the source of the given path. |
|
123 | 124 |
template <typename Digraph, typename Path> |
124 | 125 |
typename Digraph::Node pathSource(const Digraph& digraph, const Path& path) { |
125 | 126 |
return digraph.source(path.front()); |
126 | 127 |
} |
127 | 128 |
|
128 |
/// \brief |
|
129 |
/// \brief The target of a path |
|
129 | 130 |
/// |
130 |
/// |
|
131 |
/// This function returns the target of the given path. |
|
131 | 132 |
template <typename Digraph, typename Path> |
132 | 133 |
typename Digraph::Node pathTarget(const Digraph& digraph, const Path& path) { |
133 | 134 |
return digraph.target(path.back()); |
134 | 135 |
} |
135 | 136 |
|
136 |
/// \brief Class which helps to iterate the nodes of a path |
|
137 |
/// \brief Class which helps to iterate through the nodes of a path |
|
137 | 138 |
/// |
138 | 139 |
/// In a sense, the path can be treated as a list of arcs. The |
139 |
/// lemon path type stores |
|
140 |
/// lemon path type stores only this list. As a consequence, it |
|
140 | 141 |
/// cannot enumerate the nodes in the path and the zero length paths |
141 |
/// cannot |
|
142 |
/// cannot have a source node. |
|
142 | 143 |
/// |
143 | 144 |
/// This class implements the node iterator of a path structure. To |
144 |
/// provide this feature, the underlying digraph should be |
|
145 |
/// provide this feature, the underlying digraph should be passed to |
|
145 | 146 |
/// the constructor of the iterator. |
146 | 147 |
template <typename Path> |
147 | 148 |
class PathNodeIt { |
148 | 149 |
private: |
149 | 150 |
const typename Path::Digraph *_digraph; |
150 | 151 |
typename Path::ArcIt _it; |
151 | 152 |
typename Path::Digraph::Node _nd; |
152 | 153 |
|
153 | 154 |
public: |
154 | 155 |
|
155 | 156 |
typedef typename Path::Digraph Digraph; |
156 | 157 |
typedef typename Digraph::Node Node; |
157 | 158 |
|
158 | 159 |
/// Default constructor |
159 | 160 |
PathNodeIt() {} |
160 | 161 |
/// Invalid constructor |
161 | 162 |
PathNodeIt(Invalid) |
162 | 163 |
: _digraph(0), _it(INVALID), _nd(INVALID) {} |
163 | 164 |
/// Constructor |
164 | 165 |
PathNodeIt(const Digraph& digraph, const Path& path) |
165 | 166 |
: _digraph(&digraph), _it(path) { |
166 | 167 |
_nd = (_it != INVALID ? _digraph->source(_it) : INVALID); |
167 | 168 |
} |
168 | 169 |
/// Constructor |
169 | 170 |
PathNodeIt(const Digraph& digraph, const Path& path, const Node& src) |
170 | 171 |
: _digraph(&digraph), _it(path), _nd(src) {} |
171 | 172 |
|
172 | 173 |
///Conversion to Digraph::Node |
173 | 174 |
operator Node() const { |
174 | 175 |
return _nd; |
175 | 176 |
} |
176 | 177 |
|
177 | 178 |
/// Next node |
178 | 179 |
PathNodeIt& operator++() { |
179 | 180 |
if (_it == INVALID) _nd = INVALID; |
180 | 181 |
else { |
181 | 182 |
_nd = _digraph->target(_it); |
182 | 183 |
++_it; |
183 | 184 |
} |
184 | 185 |
return *this; |
185 | 186 |
} |
186 | 187 |
|
187 | 188 |
/// Comparison operator |
188 | 189 |
bool operator==(const PathNodeIt& n) const { |
189 | 190 |
return _it == n._it && _nd == n._nd; |
190 | 191 |
} |
191 | 192 |
/// Comparison operator |
192 | 193 |
bool operator!=(const PathNodeIt& n) const { |
193 | 194 |
return _it != n._it || _nd != n._nd; |
194 | 195 |
} |
195 | 196 |
/// Comparison operator |
196 | 197 |
bool operator<(const PathNodeIt& n) const { |
197 | 198 |
return (_it < n._it && _nd != INVALID); |
198 | 199 |
} |
199 | 200 |
|
200 | 201 |
}; |
201 | 202 |
|
202 | 203 |
} |
203 | 204 |
|
204 | 205 |
#endif |
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