AVL Balance Factor

The balance factor is something used to keep balance in a AVL Tree.

$\text{Balance}=\text{Height(Left Subtreee)}-\text{Height(Right Subtree)}$

Balance

• A node $X$ with $BF(X)<0$ is left heavy
• A node $X$ with $BF(X)>0$ is right heavy
• A node $X$ with $BF(X)=0$ is balanced