Heap

Heap guarantees that elements on higher levels are greater (for max-heap) or smaller (for min-heap) than elements on lower levels.

Heaps are the best when we want to get maximum or minimum of set of values, complexity of O(log n). Heaps require to have a priority of their nodes over their children. BST is good for searching in general, complexity of O(1). More about the difference between heap and BST.

Ordered binary heap helps to implement priority queue operations.