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Comparing jsr166/src/main/java/util/PriorityQueue.java (file contents):
Revision 1.11 by dholmes, Mon Jul 28 04:11:54 2003 UTC vs.
Revision 1.47 by dl, Sat Apr 10 14:31:46 2004 UTC

#	Line 1 | Line 1
1	<	package java.util;
1	>	/*
2	>	* %W% %E%
3	>	*
4	>	* Copyright 2003 Sun Microsystems, Inc. All rights reserved.
5	>	* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6	>	*/
7	>
8	>	package java.util;
9
10		/**
11	<	* An unbounded priority queue based on a priority heap.  This queue orders
12	<	* elements according to an order specified at construction time, which is
13	<	* specified in the same manner as {@link TreeSet} and {@link TreeMap}:
14	<	* elements are ordered
15	<	* either according to their <i>natural order</i> (see {@link Comparable}), or
16	<	* according to a {@link Comparator}, depending on which constructor is used.
17	<	* The <em>head</em> of this queue is the least element with respect to the
18	<	* specified ordering. If multiple elements are tied for least value, the
19	<	* head is one of those elements. A priority queue does not permit
13	<	* <tt>null</tt> elements.
14	<	*
15	<	* <p>The {@link #remove()} and {@link #poll()} methods remove and
16	<	* return the head of the queue.
11	>	* An unbounded priority {@linkplain Queue queue} based on a priority
12	>	* heap.  This queue orders elements according to an order specified
13	>	* at construction time, which is specified either according to their
14	>	* <i>natural order</i> (see {@link Comparable}), or according to a
15	>	* {@link java.util.Comparator}, depending on which constructor is
16	>	* used. A priority queue does not permit <tt>null</tt> elements.
17	>	* A priority queue relying on natural ordering also does not
18	>	* permit insertion of non-comparable objects (doing so may result
19	>	* in <tt>ClassCastException</tt>).
20		*
21	<	* <p>The {@link #element()} and {@link #peek()} methods return, but do
22	<	* not delete, the head of the queue.
21	>	* <p>The <em>head</em> of this queue is the <em>least</em> element
22	>	* with respect to the specified ordering.  If multiple elements are
23	>	* tied for least value, the head is one of those elements -- ties are
24	>	* broken arbitrarily.  The queue retrieval operations <tt>poll</tt>,
25	>	* <tt>remove</tt>, <tt>peek</tt>, and <tt>element</tt> access the
26	>	* element at the head of the queue.
27		*
28	<	* <p>A priority queue has a <i>capacity</i>.  The capacity is the
29	<	* size of the array used internally to store the elements on the
30	<	* queue.  It is always at least as large as the queue size.  As
31	<	* elements are added to a priority queue, its capacity grows
32	<	* automatically.  The details of the growth policy are not specified.
28	>	* <p>A priority queue is unbounded, but has an internal
29	>	* <i>capacity</i> governing the size of an array used to store the
30	>	* elements on the queue.  It is always at least as large as the queue
31	>	* size.  As elements are added to a priority queue, its capacity
32	>	* grows automatically.  The details of the growth policy are not
33	>	* specified.
34		*
35	+	* <p>This class implements all of the <em>optional</em> methods of
36	+	* the {@link Collection} and {@link Iterator} interfaces.  The
37	+	* Iterator provided in method {@link #iterator()} is <em>not</em>
38	+	* guaranteed to traverse the elements of the PriorityQueue in any
39	+	* particular order. If you need ordered traversal, consider using
40	+	* <tt>Arrays.sort(pq.toArray())</tt>.
41	+	*
42	+	* <p> <strong>Note that this implementation is not synchronized.</strong>
43	+	* Multiple threads should not access a <tt>PriorityQueue</tt>
44	+	* instance concurrently if any of the threads modifies the list
45	+	* structurally. Instead, use the thread-safe {@link
46	+	* java.util.concurrent.PriorityBlockingQueue} class.
47	+	*
48	+	*
49		* <p>Implementation note: this implementation provides O(log(n)) time
50		* for the insertion methods (<tt>offer</tt>, <tt>poll</tt>,
51		* <tt>remove()</tt> and <tt>add</tt>) methods; linear time for the
#	Line 35 | Line 57
57		* <a href="{@docRoot}/../guide/collections/index.html">
58		* Java Collections Framework</a>.
59		* @since 1.5
60	+	* @version %I%, %G%
61		* @author Josh Bloch
62	+	* @param <E> the type of elements held in this collection
63		*/
64		public class PriorityQueue<E> extends AbstractQueue<E>
65	<	implements Queue<E>, Sorted, java.io.Serializable {
65	>	implements java.io.Serializable {
66	>
67	>	private static final long serialVersionUID = -7720805057305804111L;
68
69		private static final int DEFAULT_INITIAL_CAPACITY = 11;
70
#	Line 55 | Line 81 | public class PriorityQueue<E> extends Ab
81		*
82		* queue.length must be >= 2, even if size == 0.
83		*/
84	<	private transient E[] queue;
84	>	private transient Object[] queue;
85
86		/**
87		* The number of elements in the priority queue.
#	Line 66 | Line 92 | public class PriorityQueue<E> extends Ab
92		* The comparator, or null if priority queue uses elements'
93		* natural ordering.
94		*/
95	<	private final Comparator<E> comparator;
95	>	private final Comparator<? super E> comparator;
96
97		/**
98		* The number of times this priority queue has been
#	Line 75 | Line 101 | public class PriorityQueue<E> extends Ab
101		private transient int modCount = 0;
102
103		/**
104	<	* Create a <tt>PriorityQueue</tt> with the default initial capacity
104	>	* Creates a <tt>PriorityQueue</tt> with the default initial capacity
105		* (11) that orders its elements according to their natural
106	<	* ordering (using <tt>Comparable</tt>.)
106	>	* ordering (using <tt>Comparable</tt>).
107		*/
108		public PriorityQueue() {
109		this(DEFAULT_INITIAL_CAPACITY, null);
110		}
111
112		/**
113	<	* Create a <tt>PriorityQueue</tt> with the specified initial capacity
113	>	* Creates a <tt>PriorityQueue</tt> with the specified initial capacity
114		* that orders its elements according to their natural ordering
115	<	* (using <tt>Comparable</tt>.)
115	>	* (using <tt>Comparable</tt>).
116		*
117		* @param initialCapacity the initial capacity for this priority queue.
118	+	* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
119	+	* than 1
120		*/
121		public PriorityQueue(int initialCapacity) {
122		this(initialCapacity, null);
123		}
124
125		/**
126	<	* Create a <tt>PriorityQueue</tt> with the specified initial capacity
126	>	* Creates a <tt>PriorityQueue</tt> with the specified initial capacity
127		* that orders its elements according to the specified comparator.
128		*
129		* @param initialCapacity the initial capacity for this priority queue.
130		* @param comparator the comparator used to order this priority queue.
131		* If <tt>null</tt> then the order depends on the elements' natural
132		* ordering.
133	+	* @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
134	+	* than 1
135		*/
136	<	public PriorityQueue(int initialCapacity, Comparator<E> comparator) {
136	>	public PriorityQueue(int initialCapacity,
137	>	Comparator<? super E> comparator) {
138		if (initialCapacity < 1)
139	<	initialCapacity = 1;
140	<	queue = (E[]) new Object[initialCapacity + 1];
139	>	throw new IllegalArgumentException();
140	>	this.queue = new Object[initialCapacity + 1];
141		this.comparator = comparator;
142		}
143
144		/**
145	<	* Create a <tt>PriorityQueue</tt> containing the elements in the specified
146	<	* collection.  The priority queue has an initial capacity of 110% of the
116	<	* size of the specified collection. If the specified collection
117	<	* implements the {@link Sorted} interface, the priority queue will be
118	<	* sorted according to the same comparator, or according to its elements'
119	<	* natural order if the collection is sorted according to its elements'
120	<	* natural order.  If the specified collection does not implement
121	<	* <tt>Sorted</tt>, the priority queue is ordered according to
122	<	* its elements' natural order.
123	<	*
124	<	* @param initialElements the collection whose elements are to be placed
125	<	*        into this priority queue.
126	<	* @throws ClassCastException if elements of the specified collection
127	<	*         cannot be compared to one another according to the priority
128	<	*         queue's ordering.
129	<	* @throws NullPointerException if the specified collection or an
130	<	*         element of the specified collection is <tt>null</tt>.
145	>	* Common code to initialize underlying queue array across
146	>	* constructors below.
147		*/
148	<	public PriorityQueue(Collection<E> initialElements) {
149	<	int sz = initialElements.size();
148	>	private void initializeArray(Collection<? extends E> c) {
149	>	int sz = c.size();
150		int initialCapacity = (int)Math.min((sz * 110L) / 100,
151		Integer.MAX_VALUE - 1);
152		if (initialCapacity < 1)
153		initialCapacity = 1;
138	–	queue = (E[]) new Object[initialCapacity + 1];
154
155	<	if (initialElements instanceof Sorted) {
156	<	comparator = ((Sorted)initialElements).comparator();
157	<	for (Iterator<E> i = initialElements.iterator(); i.hasNext(); )
158	<	queue[++size] = i.next();
155	>	this.queue = new Object[initialCapacity + 1];
156	>	}
157	>
158	>	/**
159	>	* Initially fill elements of the queue array under the
160	>	* knowledge that it is sorted or is another PQ, in which
161	>	* case we can just place the elements in the order presented.
162	>	*/
163	>	private void fillFromSorted(Collection<? extends E> c) {
164	>	for (Iterator<? extends E> i = c.iterator(); i.hasNext(); )
165	>	queue[++size] = i.next();
166	>	}
167	>
168	>	/**
169	>	* Initially fill elements of the queue array that is not to our knowledge
170	>	* sorted, so we must rearrange the elements to guarantee the heap
171	>	* invariant.
172	>	*/
173	>	private void fillFromUnsorted(Collection<? extends E> c) {
174	>	for (Iterator<? extends E> i = c.iterator(); i.hasNext(); )
175	>	queue[++size] = i.next();
176	>	heapify();
177	>	}
178	>
179	>	/**
180	>	* Creates a <tt>PriorityQueue</tt> containing the elements in the
181	>	* specified collection.  The priority queue has an initial
182	>	* capacity of 110% of the size of the specified collection or 1
183	>	* if the collection is empty.  If the specified collection is an
184	>	* instance of a {@link java.util.SortedSet} or is another
185	>	* <tt>PriorityQueue</tt>, the priority queue will be sorted
186	>	* according to the same comparator, or according to its elements'
187	>	* natural order if the collection is sorted according to its
188	>	* elements' natural order.  Otherwise, the priority queue is
189	>	* ordered according to its elements' natural order.
190	>	*
191	>	* @param c the collection whose elements are to be placed
192	>	*        into this priority queue.
193	>	* @throws ClassCastException if elements of the specified collection
194	>	*         cannot be compared to one another according to the priority
195	>	*         queue's ordering.
196	>	* @throws NullPointerException if <tt>c</tt> or any element within it
197	>	* is <tt>null</tt>
198	>	*/
199	>	public PriorityQueue(Collection<? extends E> c) {
200	>	initializeArray(c);
201	>	if (c instanceof SortedSet) {
202	>	SortedSet<? extends E> s = (SortedSet<? extends E>)c;
203	>	comparator = (Comparator<? super E>)s.comparator();
204	>	fillFromSorted(s);
205	>	} else if (c instanceof PriorityQueue) {
206	>	PriorityQueue<? extends E> s = (PriorityQueue<? extends E>) c;
207	>	comparator = (Comparator<? super E>)s.comparator();
208	>	fillFromSorted(s);
209		} else {
210		comparator = null;
211	<	for (Iterator<E> i = initialElements.iterator(); i.hasNext(); )
147	<	add(i.next());
211	>	fillFromUnsorted(c);
212		}
213		}
214
215	<	// Queue Methods
215	>	/**
216	>	* Creates a <tt>PriorityQueue</tt> containing the elements in the
217	>	* specified collection.  The priority queue has an initial
218	>	* capacity of 110% of the size of the specified collection or 1
219	>	* if the collection is empty.  This priority queue will be sorted
220	>	* according to the same comparator as the given collection, or
221	>	* according to its elements' natural order if the collection is
222	>	* sorted according to its elements' natural order.
223	>	*
224	>	* @param c the collection whose elements are to be placed
225	>	*        into this priority queue.
226	>	* @throws ClassCastException if elements of the specified collection
227	>	*         cannot be compared to one another according to the priority
228	>	*         queue's ordering.
229	>	* @throws NullPointerException if <tt>c</tt> or any element within it
230	>	* is <tt>null</tt>
231	>	*/
232	>	public PriorityQueue(PriorityQueue<? extends E> c) {
233	>	initializeArray(c);
234	>	comparator = (Comparator<? super E>)c.comparator();
235	>	fillFromSorted(c);
236	>	}
237
238		/**
239	<	* Add the specified element to this priority queue.
239	>	* Creates a <tt>PriorityQueue</tt> containing the elements in the
240	>	* specified collection.  The priority queue has an initial
241	>	* capacity of 110% of the size of the specified collection or 1
242	>	* if the collection is empty.  This priority queue will be sorted
243	>	* according to the same comparator as the given collection, or
244	>	* according to its elements' natural order if the collection is
245	>	* sorted according to its elements' natural order.
246	>	*
247	>	* @param c the collection whose elements are to be placed
248	>	*        into this priority queue.
249	>	* @throws ClassCastException if elements of the specified collection
250	>	*         cannot be compared to one another according to the priority
251	>	*         queue's ordering.
252	>	* @throws NullPointerException if <tt>c</tt> or any element within it
253	>	* is <tt>null</tt>
254	>	*/
255	>	public PriorityQueue(SortedSet<? extends E> c) {
256	>	initializeArray(c);
257	>	comparator = (Comparator<? super E>)c.comparator();
258	>	fillFromSorted(c);
259	>	}
260	>
261	>	/**
262	>	* Resize array, if necessary, to be able to hold given index
263	>	*/
264	>	private void grow(int index) {
265	>	int newlen = queue.length;
266	>	if (index < newlen) // don't need to grow
267	>	return;
268	>	if (index == Integer.MAX_VALUE)
269	>	throw new OutOfMemoryError();
270	>	while (newlen <= index) {
271	>	if (newlen >= Integer.MAX_VALUE / 2)  // avoid overflow
272	>	newlen = Integer.MAX_VALUE;
273	>	else
274	>	newlen <<= 2;
275	>	}
276	>	Object[] newQueue = new Object[newlen];
277	>	System.arraycopy(queue, 0, newQueue, 0, queue.length);
278	>	queue = newQueue;
279	>	}
280	>
281	>
282	>	/**
283	>	* Inserts the specified element into this priority queue.
284		*
156	–	* @param element the element to add.
285		* @return <tt>true</tt>
286		* @throws ClassCastException if the specified element cannot be compared
287		* with elements currently in the priority queue according
288		* to the priority queue's ordering.
289	<	* @throws NullPointerException if the specified element is null.
289	>	* @throws NullPointerException if the specified element is <tt>null</tt>.
290		*/
291	<	public boolean offer(E element) {
292	<	if (element == null)
291	>	public boolean offer(E o) {
292	>	if (o == null)
293		throw new NullPointerException();
294		modCount++;
295		++size;
296
297		// Grow backing store if necessary
298	<	while (size >= queue.length) {
299	<	E[] newQueue = (E[]) new Object[2 * queue.length];
172	<	System.arraycopy(queue, 0, newQueue, 0, queue.length);
173	<	queue = newQueue;
174	<	}
298	>	if (size >= queue.length)
299	>	grow(size);
300
301	<	queue[size] = element;
301	>	queue[size] = o;
302		fixUp(size);
303		return true;
304		}
305
306	<	public E poll() {
306	>	public E peek() {
307		if (size == 0)
308		return null;
309	<	return remove(1);
185	<	}
186	<
187	<	public E peek() {
188	<	return queue[1];
309	>	return (E) queue[1];
310		}
311
312	<	// Collection Methods
192	<
193	<	// these first two override just to get the throws docs
312	>	// Collection Methods - the first two override to update docs
313
314		/**
315	+	* Adds the specified element to this queue.
316	+	* @return <tt>true</tt> (as per the general contract of
317	+	* <tt>Collection.add</tt>).
318	+	*
319		* @throws NullPointerException if the specified element is <tt>null</tt>.
320	+	* @throws ClassCastException if the specified element cannot be compared
321	+	* with elements currently in the priority queue according
322	+	* to the priority queue's ordering.
323		*/
324	<	public boolean add(E element) {
325	<	return super.add(element);
200	<	}
201	<
202	<	/**
203	<	* @throws NullPointerException if any element is <tt>null</tt>.
204	<	*/
205	<	public boolean addAll(Collection c) {
206	<	return super.addAll(c);
324	>	public boolean add(E o) {
325	>	return offer(o);
326		}
327
328	<	/**
210	<	* @throws NullPointerException if the specified element is <tt>null</tt>.
211	<	*/
212	<	public boolean remove(E o) {
328	>	public boolean remove(Object o) {
329		if (o == null)
330	<	throw new NullPointerException();
330	>	return false;
331
332		if (comparator == null) {
333		for (int i = 1; i <= size; i++) {
334	<	if (((Comparable)queue[i]).compareTo(o) == 0) {
335	<	remove(i);
334	>	if (((Comparable<E>)queue[i]).compareTo((E)o) == 0) {
335	>	removeAt(i);
336		return true;
337		}
338		}
339		} else {
340		for (int i = 1; i <= size; i++) {
341	<	if (comparator.compare(queue[i], o) == 0) {
342	<	remove(i);
341	>	if (comparator.compare((E)queue[i], (E)o) == 0) {
342	>	removeAt(i);
343		return true;
344		}
345		}
#	Line 232 | Line 348 | public class PriorityQueue<E> extends Ab
348		}
349
350		/**
351	<	* Returns an iterator over the elements in this priority queue.  The
352	<	* elements of the priority queue will be returned by this iterator in the
237	<	* order specified by the queue, which is to say the order they would be
238	<	* returned by repeated calls to <tt>poll</tt>.
351	>	* Returns an iterator over the elements in this queue. The iterator
352	>	* does not return the elements in any particular order.
353		*
354	<	* @return an <tt>Iterator</tt> over the elements in this priority queue.
354	>	* @return an iterator over the elements in this queue.
355		*/
356		public Iterator<E> iterator() {
357		return new Itr();
358		}
359
360		private class Itr implements Iterator<E> {
361	+
362		/**
363		* Index (into queue array) of element to be returned by
364		* subsequent call to next.
#	Line 251 | Line 366 | public class PriorityQueue<E> extends Ab
366		private int cursor = 1;
367
368		/**
369	<	* Index of element returned by most recent call to next or
370	<	* previous.  Reset to 0 if this element is deleted by a call
371	<	* to remove.
369	>	* Index of element returned by most recent call to next,
370	>	* unless that element came from the forgetMeNot list.
371	>	* Reset to 0 if element is deleted by a call to remove.
372		*/
373		private int lastRet = 0;
374
#	Line 264 | Line 379 | public class PriorityQueue<E> extends Ab
379		*/
380		private int expectedModCount = modCount;
381
382	+	/**
383	+	* A list of elements that were moved from the unvisited portion of
384	+	* the heap into the visited portion as a result of "unlucky" element
385	+	* removals during the iteration.  (Unlucky element removals are those
386	+	* that require a fixup instead of a fixdown.)  We must visit all of
387	+	* the elements in this list to complete the iteration.  We do this
388	+	* after we've completed the "normal" iteration.
389	+	*
390	+	* We expect that most iterations, even those involving removals,
391	+	* will not use need to store elements in this field.
392	+	*/
393	+	private ArrayList<E> forgetMeNot = null;
394	+
395	+	/**
396	+	* Element returned by the most recent call to next iff that
397	+	* element was drawn from the forgetMeNot list.
398	+	*/
399	+	private Object lastRetElt = null;
400	+
401		public boolean hasNext() {
402	<	return cursor <= size;
402	>	return cursor <= size || forgetMeNot != null;
403		}
404
405		public E next() {
406		checkForComodification();
407	<	if (cursor > size)
407	>	E result;
408	>	if (cursor <= size) {
409	>	result = (E) queue[cursor];
410	>	lastRet = cursor++;
411	>	}
412	>	else if (forgetMeNot == null)
413		throw new NoSuchElementException();
414	<	E result = queue[cursor];
415	<	lastRet = cursor++;
414	>	else {
415	>	int remaining = forgetMeNot.size();
416	>	result = forgetMeNot.remove(remaining - 1);
417	>	if (remaining == 1)
418	>	forgetMeNot = null;
419	>	lastRet = 0;
420	>	lastRetElt = result;
421	>	}
422		return result;
423		}
424
425		public void remove() {
281	–	if (lastRet == 0)
282	–	throw new IllegalStateException();
426		checkForComodification();
427
428	<	PriorityQueue.this.remove(lastRet);
429	<	if (lastRet < cursor)
430	<	cursor--;
431	<	lastRet = 0;
428	>	if (lastRet != 0) {
429	>	E moved = PriorityQueue.this.removeAt(lastRet);
430	>	lastRet = 0;
431	>	if (moved == null) {
432	>	cursor--;
433	>	} else {
434	>	if (forgetMeNot == null)
435	>	forgetMeNot = new ArrayList<E>();
436	>	forgetMeNot.add(moved);
437	>	}
438	>	} else if (lastRetElt != null) {
439	>	PriorityQueue.this.remove(lastRetElt);
440	>	lastRetElt = null;
441	>	} else {
442	>	throw new IllegalStateException();
443	>	}
444	>
445		expectedModCount = modCount;
446		}
447
#	Line 295 | Line 451 | public class PriorityQueue<E> extends Ab
451		}
452		}
453
298	–	/**
299	–	* Returns the number of elements in this priority queue.
300	–	*
301	–	* @return the number of elements in this priority queue.
302	–	*/
454		public int size() {
455		return size;
456		}
#	Line 317 | Line 468 | public class PriorityQueue<E> extends Ab
468		size = 0;
469		}
470
471	+	public E poll() {
472	+	if (size == 0)
473	+	return null;
474	+	modCount++;
475	+
476	+	E result = (E) queue[1];
477	+	queue[1] = queue[size];
478	+	queue[size--] = null;  // Drop extra ref to prevent memory leak
479	+	if (size > 1)
480	+	fixDown(1);
481	+
482	+	return result;
483	+	}
484	+
485		/**
486	<	* Removes and returns the ith element from queue.  Recall
487	<	* that queue is one-based, so 1 <= i <= size.
486	>	* Removes and returns the ith element from queue.  (Recall that queue
487	>	* is one-based, so 1 <= i <= size.)
488		*
489	<	* XXX: Could further special-case i==size, but is it worth it?
490	<	* XXX: Could special-case i==0, but is it worth it?
489	>	* Normally this method leaves the elements at positions from 1 up to i-1,
490	>	* inclusive, untouched.  Under these circumstances, it returns null.
491	>	* Occasionally, in order to maintain the heap invariant, it must move
492	>	* the last element of the list to some index in the range [2, i-1],
493	>	* and move the element previously at position (i/2) to position i.
494	>	* Under these circumstances, this method returns the element that was
495	>	* previously at the end of the list and is now at some position between
496	>	* 2 and i-1 inclusive.
497		*/
498	<	private E remove(int i) {
499	<	assert i <= size;
498	>	private E removeAt(int i) {
499	>	assert i > 0 && i <= size;
500		modCount++;
501
502	<	E result = queue[i];
503	<	queue[i] = queue[size];
502	>	E moved = (E) queue[size];
503	>	queue[i] = moved;
504		queue[size--] = null;  // Drop extra ref to prevent memory leak
505	<	if (i <= size)
505	>	if (i <= size) {
506		fixDown(i);
507	<	return result;
507	>	if (queue[i] == moved) {
508	>	fixUp(i);
509	>	if (queue[i] != moved)
510	>	return moved;
511	>	}
512	>	}
513	>	return null;
514		}
515
516		/**
#	Line 349 | Line 526 | public class PriorityQueue<E> extends Ab
526		if (comparator == null) {
527		while (k > 1) {
528		int j = k >> 1;
529	<	if (((Comparable)queue[j]).compareTo(queue[k]) <= 0)
529	>	if (((Comparable<E>)queue[j]).compareTo((E)queue[k]) <= 0)
530		break;
531	<	E tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
531	>	Object tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
532		k = j;
533		}
534		} else {
535		while (k > 1) {
536	<	int j = k >> 1;
537	<	if (comparator.compare(queue[j], queue[k]) <= 0)
536	>	int j = k >>> 1;
537	>	if (comparator.compare((E)queue[j], (E)queue[k]) <= 0)
538		break;
539	<	E tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
539	>	Object tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
540		k = j;
541		}
542		}
#	Line 377 | Line 554 | public class PriorityQueue<E> extends Ab
554		private void fixDown(int k) {
555		int j;
556		if (comparator == null) {
557	<	while ((j = k << 1) <= size) {
558	<	if (j<size && ((Comparable)queue[j]).compareTo(queue[j+1]) > 0)
557	>	while ((j = k << 1) <= size && (j > 0)) {
558	>	if (j<size &&
559	>	((Comparable<E>)queue[j]).compareTo((E)queue[j+1]) > 0)
560		j++; // j indexes smallest kid
561	<	if (((Comparable)queue[k]).compareTo(queue[j]) <= 0)
561	>
562	>	if (((Comparable<E>)queue[k]).compareTo((E)queue[j]) <= 0)
563		break;
564	<	E tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
564	>	Object tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
565		k = j;
566		}
567		} else {
568	<	while ((j = k << 1) <= size) {
569	<	if (j < size && comparator.compare(queue[j], queue[j+1]) > 0)
568	>	while ((j = k << 1) <= size && (j > 0)) {
569	>	if (j<size &&
570	>	comparator.compare((E)queue[j], (E)queue[j+1]) > 0)
571		j++; // j indexes smallest kid
572	<	if (comparator.compare(queue[k], queue[j]) <= 0)
572	>	if (comparator.compare((E)queue[k], (E)queue[j]) <= 0)
573		break;
574	<	E tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
574	>	Object tmp = queue[j];  queue[j] = queue[k]; queue[k] = tmp;
575		k = j;
576		}
577		}
578		}
579
580	<	public Comparator comparator() {
580	>	/**
581	>	* Establishes the heap invariant (described above) in the entire tree,
582	>	* assuming nothing about the order of the elements prior to the call.
583	>	*/
584	>	private void heapify() {
585	>	for (int i = size/2; i >= 1; i--)
586	>	fixDown(i);
587	>	}
588	>
589	>	/**
590	>	* Returns the comparator used to order this collection, or <tt>null</tt>
591	>	* if this collection is sorted according to its elements natural ordering
592	>	* (using <tt>Comparable</tt>).
593	>	*
594	>	* @return the comparator used to order this collection, or <tt>null</tt>
595	>	* if this collection is sorted according to its elements natural ordering.
596	>	*/
597	>	public Comparator<? super E> comparator() {
598		return comparator;
599		}
600
#	Line 410 | Line 607 | public class PriorityQueue<E> extends Ab
607		* <tt>Object</tt>) in the proper order.
608		* @param s the stream
609		*/
610	<	private synchronized void writeObject(java.io.ObjectOutputStream s)
610	>	private void writeObject(java.io.ObjectOutputStream s)
611		throws java.io.IOException{
612		// Write out element count, and any hidden stuff
613		s.defaultWriteObject();
#	Line 419 | Line 616 | public class PriorityQueue<E> extends Ab
616		s.writeInt(queue.length);
617
618		// Write out all elements in the proper order.
619	<	for (int i=0; i<size; i++)
619	>	for (int i=1; i<=size; i++)
620		s.writeObject(queue[i]);
621		}
622
#	Line 428 | Line 625 | public class PriorityQueue<E> extends Ab
625		* deserialize it).
626		* @param s the stream
627		*/
628	<	private synchronized void readObject(java.io.ObjectInputStream s)
628	>	private void readObject(java.io.ObjectInputStream s)
629		throws java.io.IOException, ClassNotFoundException {
630		// Read in size, and any hidden stuff
631		s.defaultReadObject();
632
633		// Read in array length and allocate array
634		int arrayLength = s.readInt();
635	<	queue = (E[]) new Object[arrayLength];
635	>	queue = new Object[arrayLength];
636
637		// Read in all elements in the proper order.
638	<	for (int i=0; i<size; i++)
639	<	queue[i] = (E)s.readObject();
638	>	for (int i=1; i<=size; i++)
639	>	queue[i] = (E) s.readObject();
640		}
641
642		}
446	–

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