$[50$pts$]$ In our AVL implementation, each node stores the height of its subtree, which is an arbitrarily large

integer. The space usage for an AVL tree can be reduced by instead storing the balance factor of a node,

which is defined as the height of its left subtree minus the height of its right subtree. Thus, the balance

factor of a node is always equal to $-1,0,$ or $1,$ except during an insertion or removal, when it may become

temporarily equal to $-2$ or $+2.$ Reimplement the AVLTree class storing balance factors rather than subtree

heights.

Provide the following classes and methods:

$-$Node class,

$-$The method insertNode$(...),$ rotation methods, and all necessary methods.

$-$Test class to test your implementation,

$-$Screen shots from running your code.