Priority Queue Data Structures Explained

The underlying data structures of a PriorityQueue can be an array, linked list, binary heap, Fibonacci heap, etc.

In Java, the default implementation of PriorityQueue uses an array-based binary heap. A binary heap is a complete binary tree with specific properties.

1. The value of a parent node is always less than or equal to the value of its child nodes (min heap) or greater than or equal to the value of its child nodes (max heap).
2. A binary heap typically uses an array to store elements, allowing for quick locating of parent and child nodes based on index relationships within the array.
3. The time complexity of inserting and deleting operations in a binary heap is O(logn), where n is the number of elements in the heap.

Besides binary heaps, PriorityQueue can also be implemented using data structures like linked lists and Fibonacci heaps. Implementing with linked lists allows for fast insertion and deletion of elements, but has a higher time complexity for finding the minimum element. Fibonacci heaps are a complex data structure with more efficient insertion and deletion operations, but come with higher space complexity. The choice of underlying data structure depends on the specific requirements and performance needs.