A collection of exercises related to searching, inserting into, and deleting from AVL Trees. User points at the appropriate node, or drags-and-drops nodes as appropriate.

This works well as an exercise, since the mechanics are at the right level of granularity to gain understanding without becoming too repetitive. The exercises are easy to use. Several exercises are included.

The link above takes you to the Trakla exercise index. Click on the "AVL-tree insertion" link in the middle column under "Search Trees". The AVL AV is implemented as a Java applet and so should start up when you load the page. You will see a "stream of keys" at the top, in blue. Take the first one and drag it to the correct location in the AVL tree (in the green box). In particular, you must drag the letter to the proper little circle that correspond to the leaf nodes. If the tree is unbalanced after adding the node, then you will click the proper button below to trigger a rotation. You can click on the "Instructions" tab at the top of the applet for some instructions, and the pseudocode in the left pane will explain how to determine what to do if the tree is unbalanced. You can see what the correct series of steps would be by clicking on "Model Answer". You can have the system tell you how well you did by clicking on "Grade".