Moved the gui to glemon/trunk.
3 * This file is a part of LEMON, a generic C++ optimization library
5 * Copyright (C) 2003-2006
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
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.
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
19 #ifndef LEMON_FIB_HEAP_H
20 #define LEMON_FIB_HEAP_H
24 ///\brief Fibonacci Heap implementation.
36 ///This class implements the \e Fibonacci \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. \c Compare specifies the ordering of the priorities. In a heap
40 ///one can change the priority of an item, add or erase an item, etc.
42 ///The methods \ref increase and \ref erase are not efficient in a Fibonacci
43 ///heap. In case of many calls to these operations, it is better to use a
46 ///\param Item Type of the items to be stored.
47 ///\param Prio Type of the priority of the items.
48 ///\param ItemIntMap A read and writable Item int map, used internally
49 ///to handle the cross references.
50 ///\param Compare A class for the ordering of the priorities. The
51 ///default is \c std::less<Prio>.
55 ///\author Jacint Szabo
58 template <typename Item,
63 template <typename Item,
66 typename Compare = std::less<Prio> >
70 typedef Prio PrioType;
75 std::vector<store> container;
82 ///Status of the nodes
84 ///The node is in the heap
86 ///The node has never been in the heap
88 ///The node was in the heap but it got out of it
92 /// \brief The constructor
94 /// \c _iimap should be given to the constructor, since it is
95 /// used internally to handle the cross references.
96 explicit FibHeap(ItemIntMap &_iimap)
97 : minimum(0), iimap(_iimap), num_items() {}
99 /// \brief The constructor
101 /// \c _iimap should be given to the constructor, since it is used
102 /// internally to handle the cross references. \c _comp is an
103 /// object for ordering of the priorities.
104 FibHeap(ItemIntMap &_iimap, const Compare &_comp) : minimum(0),
105 iimap(_iimap), comp(_comp), num_items() {}
107 /// \brief The number of items stored in the heap.
109 /// Returns the number of items stored in the heap.
110 int size() const { return num_items; }
112 /// \brief Checks if the heap stores no items.
114 /// Returns \c true if and only if the heap stores no items.
115 bool empty() const { return num_items==0; }
117 /// \brief Make empty this heap.
119 /// Make empty this heap. It does not change the cross reference
120 /// map. If you want to reuse a heap what is not surely empty you
121 /// should first clear the heap and after that you should set the
122 /// cross reference map for each item to \c PRE_HEAP.
124 container.clear(); minimum = 0; num_items = 0;
127 /// \brief \c item gets to the heap with priority \c value independently
128 /// if \c item was already there.
130 /// This method calls \ref push(\c item, \c value) if \c item is not
131 /// stored in the heap and it calls \ref decrease(\c item, \c value) or
132 /// \ref increase(\c item, \c value) otherwise.
133 void set (Item const item, PrioType const value);
135 /// \brief Adds \c item to the heap with priority \c value.
137 /// Adds \c item to the heap with priority \c value.
138 /// \pre \c item must not be stored in the heap.
139 void push (Item const item, PrioType const value);
141 /// \brief Returns the item with minimum priority relative to \c Compare.
143 /// This method returns the item with minimum priority relative to \c
145 /// \pre The heap must be nonempty.
146 Item top() const { return container[minimum].name; }
148 /// \brief Returns the minimum priority relative to \c Compare.
150 /// It returns the minimum priority relative to \c Compare.
151 /// \pre The heap must be nonempty.
152 PrioType prio() const { return container[minimum].prio; }
154 /// \brief Returns the priority of \c item.
156 /// This function returns the priority of \c item.
157 /// \pre \c item must be in the heap.
158 PrioType& operator[](const Item& item) {
159 return container[iimap[item]].prio;
162 /// \brief Returns the priority of \c item.
164 /// It returns the priority of \c item.
165 /// \pre \c item must be in the heap.
166 const PrioType& operator[](const Item& item) const {
167 return container[iimap[item]].prio;
171 /// \brief Deletes the item with minimum priority relative to \c Compare.
173 /// This method deletes the item with minimum priority relative to \c
174 /// Compare from the heap.
175 /// \pre The heap must be non-empty.
178 /// \brief Deletes \c item from the heap.
180 /// This method deletes \c item from the heap, if \c item was already
181 /// stored in the heap. It is quite inefficient in Fibonacci heaps.
182 void erase (const Item& item);
184 /// \brief Decreases the priority of \c item to \c value.
186 /// This method decreases the priority of \c item to \c value.
187 /// \pre \c item must be stored in the heap with priority at least \c
188 /// value relative to \c Compare.
189 void decrease (Item item, PrioType const value);
191 /// \brief Increases the priority of \c item to \c value.
193 /// This method sets the priority of \c item to \c value. Though
194 /// there is no precondition on the priority of \c item, this
195 /// method should be used only if it is indeed necessary to increase
196 /// (relative to \c Compare) the priority of \c item, because this
197 /// method is inefficient.
198 void increase (Item item, PrioType const value) {
204 /// \brief Returns if \c item is in, has already been in, or has never
205 /// been in the heap.
207 /// This method returns PRE_HEAP if \c item has never been in the
208 /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
209 /// otherwise. In the latter case it is possible that \c item will
210 /// get back to the heap again.
211 state_enum state(const Item &item) const {
214 if ( container[i].in ) i=0;
217 return state_enum(i);
220 /// \brief Sets the state of the \c item in the heap.
222 /// Sets the state of the \c item in the heap. It can be used to
223 /// manually clear the heap when it is important to achive the
224 /// better time complexity.
225 /// \param i The item.
226 /// \param st The state. It should not be \c IN_HEAP.
227 void state(const Item& i, state_enum st) {
231 if (state(i) == IN_HEAP) {
244 void makeroot(int c);
245 void cut(int a, int b);
247 void fuse(int a, int b);
252 friend class FibHeap;
264 store() : parent(-1), child(-1), degree(), marked(false), in(true) {}
270 // **********************************************************************
272 // **********************************************************************
274 template <typename Item, typename Prio, typename ItemIntMap,
276 void FibHeap<Item, Prio, ItemIntMap, Compare>::set
277 (Item const item, PrioType const value)
280 if ( i >= 0 && container[i].in ) {
281 if ( comp(value, container[i].prio) ) decrease(item, value);
282 if ( comp(container[i].prio, value) ) increase(item, value);
283 } else push(item, value);
286 template <typename Item, typename Prio, typename ItemIntMap,
288 void FibHeap<Item, Prio, ItemIntMap, Compare>::push
289 (Item const item, PrioType const value) {
292 int s=container.size();
293 iimap.set( item, s );
296 container.push_back(st);
299 container[i].parent=container[i].child=-1;
300 container[i].degree=0;
301 container[i].in=true;
302 container[i].marked=false;
306 container[container[minimum].right_neighbor].left_neighbor=i;
307 container[i].right_neighbor=container[minimum].right_neighbor;
308 container[minimum].right_neighbor=i;
309 container[i].left_neighbor=minimum;
310 if ( comp( value, container[minimum].prio) ) minimum=i;
312 container[i].right_neighbor=container[i].left_neighbor=i;
315 container[i].prio=value;
319 template <typename Item, typename Prio, typename ItemIntMap,
321 void FibHeap<Item, Prio, ItemIntMap, Compare>::pop() {
322 /*The first case is that there are only one root.*/
323 if ( container[minimum].left_neighbor==minimum ) {
324 container[minimum].in=false;
325 if ( container[minimum].degree!=0 ) {
326 makeroot(container[minimum].child);
327 minimum=container[minimum].child;
331 int right=container[minimum].right_neighbor;
333 container[minimum].in=false;
334 if ( container[minimum].degree > 0 ) {
335 int left=container[minimum].left_neighbor;
336 int child=container[minimum].child;
337 int last_child=container[child].left_neighbor;
341 container[left].right_neighbor=child;
342 container[child].left_neighbor=left;
343 container[right].left_neighbor=last_child;
344 container[last_child].right_neighbor=right;
348 } // the case where there are more roots
353 template <typename Item, typename Prio, typename ItemIntMap,
355 void FibHeap<Item, Prio, ItemIntMap, Compare>::erase
359 if ( i >= 0 && container[i].in ) {
360 if ( container[i].parent!=-1 ) {
361 int p=container[i].parent;
365 minimum=i; //As if its prio would be -infinity
370 template <typename Item, typename Prio, typename ItemIntMap,
372 void FibHeap<Item, Prio, ItemIntMap, Compare>::decrease
373 (Item item, PrioType const value) {
375 container[i].prio=value;
376 int p=container[i].parent;
378 if ( p!=-1 && comp(value, container[p].prio) ) {
382 if ( comp(value, container[minimum].prio) ) minimum=i;
386 template <typename Item, typename Prio, typename ItemIntMap,
388 void FibHeap<Item, Prio, ItemIntMap, Compare>::balance() {
390 int maxdeg=int( std::floor( 2.08*log(double(container.size()))))+1;
392 std::vector<int> A(maxdeg,-1);
395 *Recall that now minimum does not point to the minimum prio element.
396 *We set minimum to this during balance().
398 int anchor=container[minimum].left_neighbor;
404 if ( anchor==active ) end=true;
405 int d=container[active].degree;
406 next=container[active].right_neighbor;
409 if( comp(container[active].prio, container[A[d]].prio) ) {
422 while ( container[minimum].parent >=0 ) minimum=container[minimum].parent;
426 if ( comp(container[s].prio, container[minimum].prio) ) minimum=s;
427 s=container[s].right_neighbor;
431 template <typename Item, typename Prio, typename ItemIntMap,
433 void FibHeap<Item, Prio, ItemIntMap, Compare>::makeroot
437 container[s].parent=-1;
438 s=container[s].right_neighbor;
443 template <typename Item, typename Prio, typename ItemIntMap,
445 void FibHeap<Item, Prio, ItemIntMap, Compare>::cut
448 *Replacing a from the children of b.
450 --container[b].degree;
452 if ( container[b].degree !=0 ) {
453 int child=container[b].child;
455 container[b].child=container[child].right_neighbor;
460 /*Lacing a to the roots.*/
461 int right=container[minimum].right_neighbor;
462 container[minimum].right_neighbor=a;
463 container[a].left_neighbor=minimum;
464 container[a].right_neighbor=right;
465 container[right].left_neighbor=a;
467 container[a].parent=-1;
468 container[a].marked=false;
472 template <typename Item, typename Prio, typename ItemIntMap,
474 void FibHeap<Item, Prio, ItemIntMap, Compare>::cascade
477 if ( container[a].parent!=-1 ) {
478 int p=container[a].parent;
480 if ( container[a].marked==false ) container[a].marked=true;
489 template <typename Item, typename Prio, typename ItemIntMap,
491 void FibHeap<Item, Prio, ItemIntMap, Compare>::fuse
495 /*Lacing b under a.*/
496 container[b].parent=a;
498 if (container[a].degree==0) {
499 container[b].left_neighbor=b;
500 container[b].right_neighbor=b;
501 container[a].child=b;
503 int child=container[a].child;
504 int last_child=container[child].left_neighbor;
505 container[child].left_neighbor=b;
506 container[b].right_neighbor=child;
507 container[last_child].right_neighbor=b;
508 container[b].left_neighbor=last_child;
511 ++container[a].degree;
513 container[b].marked=false;
518 *It is invoked only if a has siblings.
520 template <typename Item, typename Prio, typename ItemIntMap,
522 void FibHeap<Item, Prio, ItemIntMap, Compare>::unlace
524 int leftn=container[a].left_neighbor;
525 int rightn=container[a].right_neighbor;
526 container[leftn].right_neighbor=rightn;
527 container[rightn].left_neighbor=leftn;
533 #endif //LEMON_FIB_HEAP_H