2-3 Trees
- Each node has one or two keys
- All leaves are at the same level
- Each internal node has 1 key and 2 children or 2 keys and
3 children.
- A binary search tree containing N nodes has O(log(N)) height on
average but the height can be Θ(N).
- A 2-3 tree with N nodes always has height O(log(N))
- Specifically, in a 2-3 tree with N nodes and height h, h <=
ceiling(log2(N+1)) and N >= 2h-1.
- 2-3 trees therefore have worst case search, insertion, and
deletion performance of O(logN).