Is iterator the best way to loop through PriorityQueue

Question

I want to loop through a PriorityQueue, and wondering if following iterator() is the best way

Iterator<MyObject> itr = queue.iterator();
while(itr.hasNext()){
  MyObject element = itr.next();
  // do sth
}

I suppose its time complexity would be O(1)?
I don't care about the queue afterwards, so another way would be to use poll() while !queue.isEmpty() but the time complexity would be O(logn).

Do you care about order? iterator() won't give you any particular order. — Louis Wasserman, Jun 16 '22 at 05:10
@LouisWasserman I suppose stream also won't guarantee order then? — waynewingorc, Jun 16 '22 at 05:15
Correct. Streaming over a `PriorityQueue` will not guarantee order. In fact, the `Spliterator` returned by `PriorityQueue` does not report itself as `ORDERED`. — Slaw, Jun 16 '22 at 05:54
Fundamentally, the nature of priority queues as a data structure is that they only order themselves when elements are removed; they don't sort elements in advance. — Louis Wasserman, Jun 16 '22 at 15:34

score 1 · Accepted Answer · answered Jun 16 '22 at 05:12

1

If you want ordered retrieval of your elements, you must poll/remove elements from the queue; using iterator will not be enough.

answered Jun 16 '22 at 05:12

Louis Wasserman

191,574
25
345
413

Is iterator the best way to loop through PriorityQueue

1 Answers1