Question

In java what are the main differences between the data structures deques, queues, and priority queues?

Answer 1

`Hey,

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Queue is a list where insertion is done at one end and removal is done at the other end.

Dequeue is a list where every end supports insertion and removal.
With this feature, it is possible to use the dequeue as a list and a stack at the same time as required by the application.

Priority queue does not have any ends.
In a priority queue, elements can be inserted in any order but removal of the elements is in a sorted order.
Due to this behavior, a priority queue can be used to sort the elements.

Since sorting is done only when the elements are removed from the priority queue, the PQ is easily implemented by a heap.
Using an array-based heap, elements can be inserted and deleted in O(logN).


java.util package provides implementations for all of the above.

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