Java PriorityQueue.remove() 时间复杂度？ O(log N) 还是 O(N)？

Question

PriorityQueue pq = new PriorityQueue<>(); Assuming the priorityQueue pq has size N, what is the time complexity for pq.remove()?

Is it O(log N) or O(N)?

Answer 1

From the documentation of PriorityQueue :

[...]

Implementation note: this implementation provides O(log(n)) time for the enqueuing and dequeuing methods ( offer , poll , remove() and add ); linear time for the remove(Object) and contains(Object) methods; and constant time for the retrieval methods ( peek , element , and size ).

[...]

One should, however, point out that this is not part of any interface-contract. Thus, it is an implementation detail. As such, it could change without prior notice or when using a non-Oracle JDK and should therefore not be relied upon.