AVL Trees

AVL Trees - Introduction

• Motivation: Keep search tree balanced
• All leaves are at same level


• Basic ideas:
• An AVL tree is a Binary Search Tree


• At each node, the heights of the left and right subtrees differ by zero or one


• Nodes are inserted as normal and the tree is rotated to maintain balance


• AVL trees do these operations in lg n time (maintaining balance):
• insert a key
• search for a key
• delete the value at a location


• List operations:
• search for i^th item
• insert a value at a location


• Named after 2 inventors: Adelson-Velsky and Landis (1962)


• Implementation is somewhat complicated and so Red-Black trees are more common