9(a). What is the best-case runtime for insertion into an AVL tree if we do not allow duplicate values in the tree? What case gives rise to that runtime? 9(b). Plot Twist! What's the best-case runtime for insertion if we know that every value inserted into the AVL tree will be unique i.e. if we know that no one will try to insert a duplicate value? This phrasing is actually a very subtle twist on problem 9(a) and does, in fact, change the answer 10. What are the best- and worst-case runtimes for search/retrieval in an AVL tree? How do these compare to the best- and worst- case runtimes for search/retrieval in a BST