1 | /* -*- C++ -*- |
---|
2 | * |
---|
3 | * This file is a part of LEMON, a generic C++ optimization library |
---|
4 | * |
---|
5 | * Copyright (C) 2003-2008 |
---|
6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
---|
7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
---|
8 | * |
---|
9 | * Permission to use, modify and distribute this software is granted |
---|
10 | * provided that this copyright notice appears in all copies. For |
---|
11 | * precise terms see the accompanying LICENSE file. |
---|
12 | * |
---|
13 | * This software is provided "AS IS" with no warranty of any kind, |
---|
14 | * express or implied, and with no claim as to its suitability for any |
---|
15 | * purpose. |
---|
16 | * |
---|
17 | */ |
---|
18 | |
---|
19 | #ifndef LEMON_BUCKET_HEAP_H |
---|
20 | #define LEMON_BUCKET_HEAP_H |
---|
21 | |
---|
22 | ///\ingroup auxdat |
---|
23 | ///\file |
---|
24 | ///\brief Bucket Heap implementation. |
---|
25 | |
---|
26 | #include <vector> |
---|
27 | #include <utility> |
---|
28 | #include <functional> |
---|
29 | |
---|
30 | namespace lemon { |
---|
31 | |
---|
32 | /// \ingroup auxdat |
---|
33 | /// |
---|
34 | /// \brief A Bucket Heap implementation. |
---|
35 | /// |
---|
36 | /// This class implements the \e bucket \e heap data structure. A \e heap |
---|
37 | /// is a data structure for storing items with specified values called \e |
---|
38 | /// priorities in such a way that finding the item with minimum priority is |
---|
39 | /// efficient. The bucket heap is very simple implementation, it can store |
---|
40 | /// only integer priorities and it stores for each priority in the |
---|
41 | /// \f$ [0..C) \f$ range a list of items. So it should be used only when |
---|
42 | /// the priorities are small. It is not intended to use as dijkstra heap. |
---|
43 | /// |
---|
44 | /// \param _ItemIntMap A read and writable Item int map, used internally |
---|
45 | /// to handle the cross references. |
---|
46 | /// \param minimize If the given parameter is true then the heap gives back |
---|
47 | /// the lowest priority. |
---|
48 | template <typename _ItemIntMap, bool minimize = true > |
---|
49 | class BucketHeap { |
---|
50 | |
---|
51 | public: |
---|
52 | /// \e |
---|
53 | typedef typename _ItemIntMap::Key Item; |
---|
54 | /// \e |
---|
55 | typedef int Prio; |
---|
56 | /// \e |
---|
57 | typedef std::pair<Item, Prio> Pair; |
---|
58 | /// \e |
---|
59 | typedef _ItemIntMap ItemIntMap; |
---|
60 | |
---|
61 | /// \brief Type to represent the items states. |
---|
62 | /// |
---|
63 | /// Each Item element have a state associated to it. It may be "in heap", |
---|
64 | /// "pre heap" or "post heap". The latter two are indifferent from the |
---|
65 | /// heap's point of view, but may be useful to the user. |
---|
66 | /// |
---|
67 | /// The ItemIntMap \e should be initialized in such way that it maps |
---|
68 | /// PRE_HEAP (-1) to any element to be put in the heap... |
---|
69 | enum State { |
---|
70 | IN_HEAP = 0, |
---|
71 | PRE_HEAP = -1, |
---|
72 | POST_HEAP = -2 |
---|
73 | }; |
---|
74 | |
---|
75 | public: |
---|
76 | /// \brief The constructor. |
---|
77 | /// |
---|
78 | /// The constructor. |
---|
79 | /// \param _index should be given to the constructor, since it is used |
---|
80 | /// internally to handle the cross references. The value of the map |
---|
81 | /// should be PRE_HEAP (-1) for each element. |
---|
82 | explicit BucketHeap(ItemIntMap &_index) : index(_index), minimal(0) {} |
---|
83 | |
---|
84 | /// The number of items stored in the heap. |
---|
85 | /// |
---|
86 | /// \brief Returns the number of items stored in the heap. |
---|
87 | int size() const { return data.size(); } |
---|
88 | |
---|
89 | /// \brief Checks if the heap stores no items. |
---|
90 | /// |
---|
91 | /// Returns \c true if and only if the heap stores no items. |
---|
92 | bool empty() const { return data.empty(); } |
---|
93 | |
---|
94 | /// \brief Make empty this heap. |
---|
95 | /// |
---|
96 | /// Make empty this heap. It does not change the cross reference |
---|
97 | /// map. If you want to reuse a heap what is not surely empty you |
---|
98 | /// should first clear the heap and after that you should set the |
---|
99 | /// cross reference map for each item to \c PRE_HEAP. |
---|
100 | void clear() { |
---|
101 | data.clear(); first.clear(); minimal = 0; |
---|
102 | } |
---|
103 | |
---|
104 | private: |
---|
105 | |
---|
106 | void relocate_last(int idx) { |
---|
107 | if (idx + 1 < int(data.size())) { |
---|
108 | data[idx] = data.back(); |
---|
109 | if (data[idx].prev != -1) { |
---|
110 | data[data[idx].prev].next = idx; |
---|
111 | } else { |
---|
112 | first[data[idx].value] = idx; |
---|
113 | } |
---|
114 | if (data[idx].next != -1) { |
---|
115 | data[data[idx].next].prev = idx; |
---|
116 | } |
---|
117 | index[data[idx].item] = idx; |
---|
118 | } |
---|
119 | data.pop_back(); |
---|
120 | } |
---|
121 | |
---|
122 | void unlace(int idx) { |
---|
123 | if (data[idx].prev != -1) { |
---|
124 | data[data[idx].prev].next = data[idx].next; |
---|
125 | } else { |
---|
126 | first[data[idx].value] = data[idx].next; |
---|
127 | } |
---|
128 | if (data[idx].next != -1) { |
---|
129 | data[data[idx].next].prev = data[idx].prev; |
---|
130 | } |
---|
131 | } |
---|
132 | |
---|
133 | void lace(int idx) { |
---|
134 | if (int(first.size()) <= data[idx].value) { |
---|
135 | first.resize(data[idx].value + 1, -1); |
---|
136 | } |
---|
137 | data[idx].next = first[data[idx].value]; |
---|
138 | if (data[idx].next != -1) { |
---|
139 | data[data[idx].next].prev = idx; |
---|
140 | } |
---|
141 | first[data[idx].value] = idx; |
---|
142 | data[idx].prev = -1; |
---|
143 | } |
---|
144 | |
---|
145 | public: |
---|
146 | /// \brief Insert a pair of item and priority into the heap. |
---|
147 | /// |
---|
148 | /// Adds \c p.first to the heap with priority \c p.second. |
---|
149 | /// \param p The pair to insert. |
---|
150 | void push(const Pair& p) { |
---|
151 | push(p.first, p.second); |
---|
152 | } |
---|
153 | |
---|
154 | /// \brief Insert an item into the heap with the given priority. |
---|
155 | /// |
---|
156 | /// Adds \c i to the heap with priority \c p. |
---|
157 | /// \param i The item to insert. |
---|
158 | /// \param p The priority of the item. |
---|
159 | void push(const Item &i, const Prio &p) { |
---|
160 | int idx = data.size(); |
---|
161 | index[i] = idx; |
---|
162 | data.push_back(BucketItem(i, p)); |
---|
163 | lace(idx); |
---|
164 | if (p < minimal) { |
---|
165 | minimal = p; |
---|
166 | } |
---|
167 | } |
---|
168 | |
---|
169 | /// \brief Returns the item with minimum priority. |
---|
170 | /// |
---|
171 | /// This method returns the item with minimum priority. |
---|
172 | /// \pre The heap must be nonempty. |
---|
173 | Item top() const { |
---|
174 | while (first[minimal] == -1) { |
---|
175 | ++minimal; |
---|
176 | } |
---|
177 | return data[first[minimal]].item; |
---|
178 | } |
---|
179 | |
---|
180 | /// \brief Returns the minimum priority. |
---|
181 | /// |
---|
182 | /// It returns the minimum priority. |
---|
183 | /// \pre The heap must be nonempty. |
---|
184 | Prio prio() const { |
---|
185 | while (first[minimal] == -1) { |
---|
186 | ++minimal; |
---|
187 | } |
---|
188 | return minimal; |
---|
189 | } |
---|
190 | |
---|
191 | /// \brief Deletes the item with minimum priority. |
---|
192 | /// |
---|
193 | /// This method deletes the item with minimum priority from the heap. |
---|
194 | /// \pre The heap must be non-empty. |
---|
195 | void pop() { |
---|
196 | while (first[minimal] == -1) { |
---|
197 | ++minimal; |
---|
198 | } |
---|
199 | int idx = first[minimal]; |
---|
200 | index[data[idx].item] = -2; |
---|
201 | unlace(idx); |
---|
202 | relocate_last(idx); |
---|
203 | } |
---|
204 | |
---|
205 | /// \brief Deletes \c i from the heap. |
---|
206 | /// |
---|
207 | /// This method deletes item \c i from the heap, if \c i was |
---|
208 | /// already stored in the heap. |
---|
209 | /// \param i The item to erase. |
---|
210 | void erase(const Item &i) { |
---|
211 | int idx = index[i]; |
---|
212 | index[data[idx].item] = -2; |
---|
213 | unlace(idx); |
---|
214 | relocate_last(idx); |
---|
215 | } |
---|
216 | |
---|
217 | |
---|
218 | /// \brief Returns the priority of \c i. |
---|
219 | /// |
---|
220 | /// This function returns the priority of item \c i. |
---|
221 | /// \pre \c i must be in the heap. |
---|
222 | /// \param i The item. |
---|
223 | Prio operator[](const Item &i) const { |
---|
224 | int idx = index[i]; |
---|
225 | return data[idx].value; |
---|
226 | } |
---|
227 | |
---|
228 | /// \brief \c i gets to the heap with priority \c p independently |
---|
229 | /// if \c i was already there. |
---|
230 | /// |
---|
231 | /// This method calls \ref push(\c i, \c p) if \c i is not stored |
---|
232 | /// in the heap and sets the priority of \c i to \c p otherwise. |
---|
233 | /// \param i The item. |
---|
234 | /// \param p The priority. |
---|
235 | void set(const Item &i, const Prio &p) { |
---|
236 | int idx = index[i]; |
---|
237 | if (idx < 0) { |
---|
238 | push(i,p); |
---|
239 | } else if (p > data[idx].value) { |
---|
240 | increase(i, p); |
---|
241 | } else { |
---|
242 | decrease(i, p); |
---|
243 | } |
---|
244 | } |
---|
245 | |
---|
246 | /// \brief Decreases the priority of \c i to \c p. |
---|
247 | /// |
---|
248 | /// This method decreases the priority of item \c i to \c p. |
---|
249 | /// \pre \c i must be stored in the heap with priority at least \c |
---|
250 | /// p relative to \c Compare. |
---|
251 | /// \param i The item. |
---|
252 | /// \param p The priority. |
---|
253 | void decrease(const Item &i, const Prio &p) { |
---|
254 | int idx = index[i]; |
---|
255 | unlace(idx); |
---|
256 | data[idx].value = p; |
---|
257 | if (p < minimal) { |
---|
258 | minimal = p; |
---|
259 | } |
---|
260 | lace(idx); |
---|
261 | } |
---|
262 | |
---|
263 | /// \brief Increases the priority of \c i to \c p. |
---|
264 | /// |
---|
265 | /// This method sets the priority of item \c i to \c p. |
---|
266 | /// \pre \c i must be stored in the heap with priority at most \c |
---|
267 | /// p relative to \c Compare. |
---|
268 | /// \param i The item. |
---|
269 | /// \param p The priority. |
---|
270 | void increase(const Item &i, const Prio &p) { |
---|
271 | int idx = index[i]; |
---|
272 | unlace(idx); |
---|
273 | data[idx].value = p; |
---|
274 | lace(idx); |
---|
275 | } |
---|
276 | |
---|
277 | /// \brief Returns if \c item is in, has already been in, or has |
---|
278 | /// never been in the heap. |
---|
279 | /// |
---|
280 | /// This method returns PRE_HEAP if \c item has never been in the |
---|
281 | /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP |
---|
282 | /// otherwise. In the latter case it is possible that \c item will |
---|
283 | /// get back to the heap again. |
---|
284 | /// \param i The item. |
---|
285 | State state(const Item &i) const { |
---|
286 | int idx = index[i]; |
---|
287 | if (idx >= 0) idx = 0; |
---|
288 | return State(idx); |
---|
289 | } |
---|
290 | |
---|
291 | /// \brief Sets the state of the \c item in the heap. |
---|
292 | /// |
---|
293 | /// Sets the state of the \c item in the heap. It can be used to |
---|
294 | /// manually clear the heap when it is important to achive the |
---|
295 | /// better time complexity. |
---|
296 | /// \param i The item. |
---|
297 | /// \param st The state. It should not be \c IN_HEAP. |
---|
298 | void state(const Item& i, State st) { |
---|
299 | switch (st) { |
---|
300 | case POST_HEAP: |
---|
301 | case PRE_HEAP: |
---|
302 | if (state(i) == IN_HEAP) { |
---|
303 | erase(i); |
---|
304 | } |
---|
305 | index[i] = st; |
---|
306 | break; |
---|
307 | case IN_HEAP: |
---|
308 | break; |
---|
309 | } |
---|
310 | } |
---|
311 | |
---|
312 | private: |
---|
313 | |
---|
314 | struct BucketItem { |
---|
315 | BucketItem(const Item& _item, int _value) |
---|
316 | : item(_item), value(_value) {} |
---|
317 | |
---|
318 | Item item; |
---|
319 | int value; |
---|
320 | |
---|
321 | int prev, next; |
---|
322 | }; |
---|
323 | |
---|
324 | ItemIntMap& index; |
---|
325 | std::vector<int> first; |
---|
326 | std::vector<BucketItem> data; |
---|
327 | mutable int minimal; |
---|
328 | |
---|
329 | }; // class BucketHeap |
---|
330 | |
---|
331 | |
---|
332 | template <typename _ItemIntMap> |
---|
333 | class BucketHeap<_ItemIntMap, false> { |
---|
334 | |
---|
335 | public: |
---|
336 | typedef typename _ItemIntMap::Key Item; |
---|
337 | typedef int Prio; |
---|
338 | typedef std::pair<Item, Prio> Pair; |
---|
339 | typedef _ItemIntMap ItemIntMap; |
---|
340 | |
---|
341 | enum State { |
---|
342 | IN_HEAP = 0, |
---|
343 | PRE_HEAP = -1, |
---|
344 | POST_HEAP = -2 |
---|
345 | }; |
---|
346 | |
---|
347 | public: |
---|
348 | |
---|
349 | explicit BucketHeap(ItemIntMap &_index) : index(_index), maximal(-1) {} |
---|
350 | |
---|
351 | int size() const { return data.size(); } |
---|
352 | bool empty() const { return data.empty(); } |
---|
353 | |
---|
354 | void clear() { |
---|
355 | data.clear(); first.clear(); maximal = -1; |
---|
356 | } |
---|
357 | |
---|
358 | private: |
---|
359 | |
---|
360 | void relocate_last(int idx) { |
---|
361 | if (idx + 1 != int(data.size())) { |
---|
362 | data[idx] = data.back(); |
---|
363 | if (data[idx].prev != -1) { |
---|
364 | data[data[idx].prev].next = idx; |
---|
365 | } else { |
---|
366 | first[data[idx].value] = idx; |
---|
367 | } |
---|
368 | if (data[idx].next != -1) { |
---|
369 | data[data[idx].next].prev = idx; |
---|
370 | } |
---|
371 | index[data[idx].item] = idx; |
---|
372 | } |
---|
373 | data.pop_back(); |
---|
374 | } |
---|
375 | |
---|
376 | void unlace(int idx) { |
---|
377 | if (data[idx].prev != -1) { |
---|
378 | data[data[idx].prev].next = data[idx].next; |
---|
379 | } else { |
---|
380 | first[data[idx].value] = data[idx].next; |
---|
381 | } |
---|
382 | if (data[idx].next != -1) { |
---|
383 | data[data[idx].next].prev = data[idx].prev; |
---|
384 | } |
---|
385 | } |
---|
386 | |
---|
387 | void lace(int idx) { |
---|
388 | if (int(first.size()) <= data[idx].value) { |
---|
389 | first.resize(data[idx].value + 1, -1); |
---|
390 | } |
---|
391 | data[idx].next = first[data[idx].value]; |
---|
392 | if (data[idx].next != -1) { |
---|
393 | data[data[idx].next].prev = idx; |
---|
394 | } |
---|
395 | first[data[idx].value] = idx; |
---|
396 | data[idx].prev = -1; |
---|
397 | } |
---|
398 | |
---|
399 | public: |
---|
400 | |
---|
401 | void push(const Pair& p) { |
---|
402 | push(p.first, p.second); |
---|
403 | } |
---|
404 | |
---|
405 | void push(const Item &i, const Prio &p) { |
---|
406 | int idx = data.size(); |
---|
407 | index[i] = idx; |
---|
408 | data.push_back(BucketItem(i, p)); |
---|
409 | lace(idx); |
---|
410 | if (data[idx].value > maximal) { |
---|
411 | maximal = data[idx].value; |
---|
412 | } |
---|
413 | } |
---|
414 | |
---|
415 | Item top() const { |
---|
416 | while (first[maximal] == -1) { |
---|
417 | --maximal; |
---|
418 | } |
---|
419 | return data[first[maximal]].item; |
---|
420 | } |
---|
421 | |
---|
422 | Prio prio() const { |
---|
423 | while (first[maximal] == -1) { |
---|
424 | --maximal; |
---|
425 | } |
---|
426 | return maximal; |
---|
427 | } |
---|
428 | |
---|
429 | void pop() { |
---|
430 | while (first[maximal] == -1) { |
---|
431 | --maximal; |
---|
432 | } |
---|
433 | int idx = first[maximal]; |
---|
434 | index[data[idx].item] = -2; |
---|
435 | unlace(idx); |
---|
436 | relocate_last(idx); |
---|
437 | } |
---|
438 | |
---|
439 | void erase(const Item &i) { |
---|
440 | int idx = index[i]; |
---|
441 | index[data[idx].item] = -2; |
---|
442 | unlace(idx); |
---|
443 | relocate_last(idx); |
---|
444 | } |
---|
445 | |
---|
446 | Prio operator[](const Item &i) const { |
---|
447 | int idx = index[i]; |
---|
448 | return data[idx].value; |
---|
449 | } |
---|
450 | |
---|
451 | void set(const Item &i, const Prio &p) { |
---|
452 | int idx = index[i]; |
---|
453 | if (idx < 0) { |
---|
454 | push(i,p); |
---|
455 | } else if (p > data[idx].value) { |
---|
456 | decrease(i, p); |
---|
457 | } else { |
---|
458 | increase(i, p); |
---|
459 | } |
---|
460 | } |
---|
461 | |
---|
462 | void decrease(const Item &i, const Prio &p) { |
---|
463 | int idx = index[i]; |
---|
464 | unlace(idx); |
---|
465 | data[idx].value = p; |
---|
466 | if (p > maximal) { |
---|
467 | maximal = p; |
---|
468 | } |
---|
469 | lace(idx); |
---|
470 | } |
---|
471 | |
---|
472 | void increase(const Item &i, const Prio &p) { |
---|
473 | int idx = index[i]; |
---|
474 | unlace(idx); |
---|
475 | data[idx].value = p; |
---|
476 | lace(idx); |
---|
477 | } |
---|
478 | |
---|
479 | State state(const Item &i) const { |
---|
480 | int idx = index[i]; |
---|
481 | if (idx >= 0) idx = 0; |
---|
482 | return State(idx); |
---|
483 | } |
---|
484 | |
---|
485 | void state(const Item& i, State st) { |
---|
486 | switch (st) { |
---|
487 | case POST_HEAP: |
---|
488 | case PRE_HEAP: |
---|
489 | if (state(i) == IN_HEAP) { |
---|
490 | erase(i); |
---|
491 | } |
---|
492 | index[i] = st; |
---|
493 | break; |
---|
494 | case IN_HEAP: |
---|
495 | break; |
---|
496 | } |
---|
497 | } |
---|
498 | |
---|
499 | private: |
---|
500 | |
---|
501 | struct BucketItem { |
---|
502 | BucketItem(const Item& _item, int _value) |
---|
503 | : item(_item), value(_value) {} |
---|
504 | |
---|
505 | Item item; |
---|
506 | int value; |
---|
507 | |
---|
508 | int prev, next; |
---|
509 | }; |
---|
510 | |
---|
511 | ItemIntMap& index; |
---|
512 | std::vector<int> first; |
---|
513 | std::vector<BucketItem> data; |
---|
514 | mutable int maximal; |
---|
515 | |
---|
516 | }; // class BucketHeap |
---|
517 | |
---|
518 | /// \ingroup auxdat |
---|
519 | /// |
---|
520 | /// \brief A Simplified Bucket Heap implementation. |
---|
521 | /// |
---|
522 | /// This class implements a simplified \e bucket \e heap data |
---|
523 | /// structure. It does not provide some functionality but it faster |
---|
524 | /// and simplier data structure than the BucketHeap. The main |
---|
525 | /// difference is that the BucketHeap stores for every key a double |
---|
526 | /// linked list while this class stores just simple lists. In the |
---|
527 | /// other way it does not supports erasing each elements just the |
---|
528 | /// minimal and it does not supports key increasing, decreasing. |
---|
529 | /// |
---|
530 | /// \param _ItemIntMap A read and writable Item int map, used internally |
---|
531 | /// to handle the cross references. |
---|
532 | /// \param minimize If the given parameter is true then the heap gives back |
---|
533 | /// the lowest priority. |
---|
534 | /// |
---|
535 | /// \sa BucketHeap |
---|
536 | template <typename _ItemIntMap, bool minimize = true > |
---|
537 | class SimpleBucketHeap { |
---|
538 | |
---|
539 | public: |
---|
540 | typedef typename _ItemIntMap::Key Item; |
---|
541 | typedef int Prio; |
---|
542 | typedef std::pair<Item, Prio> Pair; |
---|
543 | typedef _ItemIntMap ItemIntMap; |
---|
544 | |
---|
545 | /// \brief Type to represent the items states. |
---|
546 | /// |
---|
547 | /// Each Item element have a state associated to it. It may be "in heap", |
---|
548 | /// "pre heap" or "post heap". The latter two are indifferent from the |
---|
549 | /// heap's point of view, but may be useful to the user. |
---|
550 | /// |
---|
551 | /// The ItemIntMap \e should be initialized in such way that it maps |
---|
552 | /// PRE_HEAP (-1) to any element to be put in the heap... |
---|
553 | enum State { |
---|
554 | IN_HEAP = 0, |
---|
555 | PRE_HEAP = -1, |
---|
556 | POST_HEAP = -2 |
---|
557 | }; |
---|
558 | |
---|
559 | public: |
---|
560 | |
---|
561 | /// \brief The constructor. |
---|
562 | /// |
---|
563 | /// The constructor. |
---|
564 | /// \param _index should be given to the constructor, since it is used |
---|
565 | /// internally to handle the cross references. The value of the map |
---|
566 | /// should be PRE_HEAP (-1) for each element. |
---|
567 | explicit SimpleBucketHeap(ItemIntMap &_index) |
---|
568 | : index(_index), free(-1), num(0), minimal(0) {} |
---|
569 | |
---|
570 | /// \brief Returns the number of items stored in the heap. |
---|
571 | /// |
---|
572 | /// The number of items stored in the heap. |
---|
573 | int size() const { return num; } |
---|
574 | |
---|
575 | /// \brief Checks if the heap stores no items. |
---|
576 | /// |
---|
577 | /// Returns \c true if and only if the heap stores no items. |
---|
578 | bool empty() const { return num == 0; } |
---|
579 | |
---|
580 | /// \brief Make empty this heap. |
---|
581 | /// |
---|
582 | /// Make empty this heap. It does not change the cross reference |
---|
583 | /// map. If you want to reuse a heap what is not surely empty you |
---|
584 | /// should first clear the heap and after that you should set the |
---|
585 | /// cross reference map for each item to \c PRE_HEAP. |
---|
586 | void clear() { |
---|
587 | data.clear(); first.clear(); free = -1; num = 0; minimal = 0; |
---|
588 | } |
---|
589 | |
---|
590 | /// \brief Insert a pair of item and priority into the heap. |
---|
591 | /// |
---|
592 | /// Adds \c p.first to the heap with priority \c p.second. |
---|
593 | /// \param p The pair to insert. |
---|
594 | void push(const Pair& p) { |
---|
595 | push(p.first, p.second); |
---|
596 | } |
---|
597 | |
---|
598 | /// \brief Insert an item into the heap with the given priority. |
---|
599 | /// |
---|
600 | /// Adds \c i to the heap with priority \c p. |
---|
601 | /// \param i The item to insert. |
---|
602 | /// \param p The priority of the item. |
---|
603 | void push(const Item &i, const Prio &p) { |
---|
604 | int idx; |
---|
605 | if (free == -1) { |
---|
606 | idx = data.size(); |
---|
607 | data.push_back(BucketItem(i)); |
---|
608 | } else { |
---|
609 | idx = free; |
---|
610 | free = data[idx].next; |
---|
611 | data[idx].item = i; |
---|
612 | } |
---|
613 | index[i] = idx; |
---|
614 | if (p >= int(first.size())) first.resize(p + 1, -1); |
---|
615 | data[idx].next = first[p]; |
---|
616 | first[p] = idx; |
---|
617 | if (p < minimal) { |
---|
618 | minimal = p; |
---|
619 | } |
---|
620 | ++num; |
---|
621 | } |
---|
622 | |
---|
623 | /// \brief Returns the item with minimum priority. |
---|
624 | /// |
---|
625 | /// This method returns the item with minimum priority. |
---|
626 | /// \pre The heap must be nonempty. |
---|
627 | Item top() const { |
---|
628 | while (first[minimal] == -1) { |
---|
629 | ++minimal; |
---|
630 | } |
---|
631 | return data[first[minimal]].item; |
---|
632 | } |
---|
633 | |
---|
634 | /// \brief Returns the minimum priority. |
---|
635 | /// |
---|
636 | /// It returns the minimum priority. |
---|
637 | /// \pre The heap must be nonempty. |
---|
638 | Prio prio() const { |
---|
639 | while (first[minimal] == -1) { |
---|
640 | ++minimal; |
---|
641 | } |
---|
642 | return minimal; |
---|
643 | } |
---|
644 | |
---|
645 | /// \brief Deletes the item with minimum priority. |
---|
646 | /// |
---|
647 | /// This method deletes the item with minimum priority from the heap. |
---|
648 | /// \pre The heap must be non-empty. |
---|
649 | void pop() { |
---|
650 | while (first[minimal] == -1) { |
---|
651 | ++minimal; |
---|
652 | } |
---|
653 | int idx = first[minimal]; |
---|
654 | index[data[idx].item] = -2; |
---|
655 | first[minimal] = data[idx].next; |
---|
656 | data[idx].next = free; |
---|
657 | free = idx; |
---|
658 | --num; |
---|
659 | } |
---|
660 | |
---|
661 | /// \brief Returns the priority of \c i. |
---|
662 | /// |
---|
663 | /// This function returns the priority of item \c i. |
---|
664 | /// \warning This operator is not a constant time function |
---|
665 | /// because it scans the whole data structure to find the proper |
---|
666 | /// value. |
---|
667 | /// \pre \c i must be in the heap. |
---|
668 | /// \param i The item. |
---|
669 | Prio operator[](const Item &i) const { |
---|
670 | for (int k = 0; k < first.size(); ++k) { |
---|
671 | int idx = first[k]; |
---|
672 | while (idx != -1) { |
---|
673 | if (data[idx].item == i) { |
---|
674 | return k; |
---|
675 | } |
---|
676 | idx = data[idx].next; |
---|
677 | } |
---|
678 | } |
---|
679 | return -1; |
---|
680 | } |
---|
681 | |
---|
682 | /// \brief Returns if \c item is in, has already been in, or has |
---|
683 | /// never been in the heap. |
---|
684 | /// |
---|
685 | /// This method returns PRE_HEAP if \c item has never been in the |
---|
686 | /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP |
---|
687 | /// otherwise. In the latter case it is possible that \c item will |
---|
688 | /// get back to the heap again. |
---|
689 | /// \param i The item. |
---|
690 | State state(const Item &i) const { |
---|
691 | int idx = index[i]; |
---|
692 | if (idx >= 0) idx = 0; |
---|
693 | return State(idx); |
---|
694 | } |
---|
695 | |
---|
696 | private: |
---|
697 | |
---|
698 | struct BucketItem { |
---|
699 | BucketItem(const Item& _item) |
---|
700 | : item(_item) {} |
---|
701 | |
---|
702 | Item item; |
---|
703 | int next; |
---|
704 | }; |
---|
705 | |
---|
706 | ItemIntMap& index; |
---|
707 | std::vector<int> first; |
---|
708 | std::vector<BucketItem> data; |
---|
709 | int free, num; |
---|
710 | mutable int minimal; |
---|
711 | |
---|
712 | }; // class SimpleBucketHeap |
---|
713 | |
---|
714 | template <typename _ItemIntMap> |
---|
715 | class SimpleBucketHeap<_ItemIntMap, false> { |
---|
716 | |
---|
717 | public: |
---|
718 | typedef typename _ItemIntMap::Key Item; |
---|
719 | typedef int Prio; |
---|
720 | typedef std::pair<Item, Prio> Pair; |
---|
721 | typedef _ItemIntMap ItemIntMap; |
---|
722 | |
---|
723 | enum State { |
---|
724 | IN_HEAP = 0, |
---|
725 | PRE_HEAP = -1, |
---|
726 | POST_HEAP = -2 |
---|
727 | }; |
---|
728 | |
---|
729 | public: |
---|
730 | |
---|
731 | explicit SimpleBucketHeap(ItemIntMap &_index) |
---|
732 | : index(_index), free(-1), num(0), maximal(0) {} |
---|
733 | |
---|
734 | int size() const { return num; } |
---|
735 | |
---|
736 | bool empty() const { return num == 0; } |
---|
737 | |
---|
738 | void clear() { |
---|
739 | data.clear(); first.clear(); free = -1; num = 0; maximal = 0; |
---|
740 | } |
---|
741 | |
---|
742 | void push(const Pair& p) { |
---|
743 | push(p.first, p.second); |
---|
744 | } |
---|
745 | |
---|
746 | void push(const Item &i, const Prio &p) { |
---|
747 | int idx; |
---|
748 | if (free == -1) { |
---|
749 | idx = data.size(); |
---|
750 | data.push_back(BucketItem(i)); |
---|
751 | } else { |
---|
752 | idx = free; |
---|
753 | free = data[idx].next; |
---|
754 | data[idx].item = i; |
---|
755 | } |
---|
756 | index[i] = idx; |
---|
757 | if (p >= int(first.size())) first.resize(p + 1, -1); |
---|
758 | data[idx].next = first[p]; |
---|
759 | first[p] = idx; |
---|
760 | if (p > maximal) { |
---|
761 | maximal = p; |
---|
762 | } |
---|
763 | ++num; |
---|
764 | } |
---|
765 | |
---|
766 | Item top() const { |
---|
767 | while (first[maximal] == -1) { |
---|
768 | --maximal; |
---|
769 | } |
---|
770 | return data[first[maximal]].item; |
---|
771 | } |
---|
772 | |
---|
773 | Prio prio() const { |
---|
774 | while (first[maximal] == -1) { |
---|
775 | --maximal; |
---|
776 | } |
---|
777 | return maximal; |
---|
778 | } |
---|
779 | |
---|
780 | void pop() { |
---|
781 | while (first[maximal] == -1) { |
---|
782 | --maximal; |
---|
783 | } |
---|
784 | int idx = first[maximal]; |
---|
785 | index[data[idx].item] = -2; |
---|
786 | first[maximal] = data[idx].next; |
---|
787 | data[idx].next = free; |
---|
788 | free = idx; |
---|
789 | --num; |
---|
790 | } |
---|
791 | |
---|
792 | Prio operator[](const Item &i) const { |
---|
793 | for (int k = 0; k < first.size(); ++k) { |
---|
794 | int idx = first[k]; |
---|
795 | while (idx != -1) { |
---|
796 | if (data[idx].item == i) { |
---|
797 | return k; |
---|
798 | } |
---|
799 | idx = data[idx].next; |
---|
800 | } |
---|
801 | } |
---|
802 | return -1; |
---|
803 | } |
---|
804 | |
---|
805 | State state(const Item &i) const { |
---|
806 | int idx = index[i]; |
---|
807 | if (idx >= 0) idx = 0; |
---|
808 | return State(idx); |
---|
809 | } |
---|
810 | |
---|
811 | private: |
---|
812 | |
---|
813 | struct BucketItem { |
---|
814 | BucketItem(const Item& _item) : item(_item) {} |
---|
815 | |
---|
816 | Item item; |
---|
817 | |
---|
818 | int next; |
---|
819 | }; |
---|
820 | |
---|
821 | ItemIntMap& index; |
---|
822 | std::vector<int> first; |
---|
823 | std::vector<BucketItem> data; |
---|
824 | int free, num; |
---|
825 | mutable int maximal; |
---|
826 | |
---|
827 | }; |
---|
828 | |
---|
829 | } |
---|
830 | |
---|
831 | #endif |
---|