AVL Tree: Lookup cost
Time to perform FIND(k) in AVL tree T is proportional to the depth of the node containing key k.
where c ? 1.44 (see Sahni, p.605).
Therefore, the time for FIND(k) is O(log n) in both the worst case and expected case.
The worst case time for hashing is ?(D + n) although the expected case time when the load factor is low is O(1).