AVL tree operations.

Show the process of inserting 2, 1, 4, 5, 9, 3, 6, 7 into an initially empty AVL tree, and clearly indicate the final result. For each value inserted, show your work.

For each insert, in case a rotation is needed, you should show the figure before and after rotation, and clearly indicate whether it is a single rotation (and mark k1 and k2) or a double rotation (and mark k1, k2 and k3).