Van Emde Boas Tree
A Van Emde Boas tree is a recursive data structure for maintaining a dynamic set of integers from a bounded universe of size U. It supports predecessor, successor, insertion, deletion, and membership in O(log log U) time, which is asymptotically faster than comparison-based balanced trees when the universe is sufficiently constrained.
Designed for integer keys from a bounded universe.
Operations can run in O(log log U).
Classic implementations can have significant space requirements.
Useful when the universe size is manageable and very fast predecessor/successor operations matter.