class AVLTree extends BSNode {

    public int getBalanceFactor() {
       int leftHight = getLeft() == null ? 0 : getLeft().getHight(),
           rightHight = getRight() == null ? 0 : getRight().getHight();

        return leftHight - rightHight;
    }

    public BSNode rightRotate(BSNode node) {
        BSNode nodeLeft = node.getLeft();
        node.setLeft(nodeLeft.getRight());
        nodeLeft.setRight(node);

        //Update heights
        node.setHeight(Math.max(node.getLeft().getHeight(), node.getRight().getHeight()) + 1);
        nodeLeft.setHeight(Math.max(nodeLeft.getLeft().getHeight(), nodeLeft.getRight().getHeight())) + 1);

        //Return the new parent node
        return nodeLeft;
    }

    public BSNode leftRotate(BSNode node) {
        //Rote nodes
        BSNode nodeRight = node.getRight();
        root.setRight(nodeRight.getLeft());
        nodeRight.setLeft(node);

        //Update heights
        node.setHeight(Math.max(node.getLeft().getHeight(), node.getRight().getHeight()) + 1);
        nodeRight.setHeight(Math.max(nodeRight.getLeft().getHeight(), nodeRight.getRight().getHeight())) + 1);

        //Return the new parent node
        return nodeRight;
    }

    @Override
    public void insert(<T> data) {
        throw new InvalidArgumentException("This value already exists");
    }
}