A no-arg constructor is shown in Program .
This constructor creates an empty AVL tree.
The height field is set to the value -1,
which is consistent with the empty tree.
Notice that according to Definition
,
the empty tree is AVL balanced.
Therefore, the result is a valid AVL tree.
Clearly, the running time of the constructor is O(1).
Program: AVLTree class constructor, getHeight, adjustHeight, and getBalanceFactor methods.