Concepts4

A splay tree is a self-adjusting binary search tree that moves the most recently accessed node to the root with rotations.

A persistent segment tree stores every historical version of an array-like data while supporting queries and updates in O(log n) time.

A treap is a binary search tree on keys combined with a heap on random priorities, which keeps the tree balanced in expectation.

A dynamic segment tree stores values over a huge coordinate range by creating nodes only when an operation touches their interval.