Dictionaries
BST
AVL
search: $\theta(height)$
insert: $\theta(height)$
delete: $\theta(height)$
Worst case cost for all operations is $\theta(height) = \theta(log \space n)$
Other Dictionary Implementations
Dictionary ADT
Skip Lists
Expected Space: O(n)
Expected height: O(log n)
search: O(log n)
insert: O(log n)