Fenwick Tree’s efficiency, combined with its relatively simple implementation, makes it useful in competitive programming and applications that involve dynamic sum queries and updates.
Treap is an efficient and simple data structure that combines the best of both binary search trees and heaps. It provides the benefits of efficient search, insert, and delete operations.
Disjoint-set data structures, commonly known as Union-Find, are fundamental data-structures in computer science for efficiently solving problems related to connectivity in graphs or set operations.