Before jumping into the actual techniques, it's important to understand what **balance factor** is.

# Balance Factor
The **balance factor** of a node is the difference in the heights of the left and right subtrees. The balance factor of every node in the AVL tree should be either **+1**, **0** or **-1**.

In case a node is imbalanced, a *rotation technique* can be applied to balance it. Some common ones are below.

# Rotation Techniques

### Right Rotation
A single rotation applied when a node is inserted in the left subtree of a left subtree. In the given example, **node C** now has a balance factor of 2 after the insertion of **node A**. By rotating the tree right, **node B** becomes the root resulting in a balanced tree.   


### Left Rotation
A single rotation applied when a node is inserted in the right subtree of a right subtree. In the given example, **node A** has a balance factor of 2 after the insertion of **node C**. By rotating the tree left, **node B** becomes the root resulting in a balanced tree.  


### Left-Right Rotation
A double rotation in which a *left rotation* is followed by a *right rotation*. In the given example, **node B** is causing an imbalance resulting in **node C** to have a balance factor of 2. As **node B** is inserted in the right subtree of **node A**, a *left rotation* needs to be applied. However, a single rotation will not give us the required results. Now, all we have to do is apply the *right rotation* as shown before to achieve a balanced tree.

### Right-Left Rotation
A double rotation in which a *right rotation* is followed by a *left rotation*. In the given example, **node B** is causing an imbalance resulting in **node A** to have a balance factor of 2. As **node B** is inserted in the left subtree of **node C**, a *right rotation* needs to be applied. However, just as before, a single rotation will not give us the required results. Now, by applying the *left rotation* as shown before, we can achieve a balanced tree.



Common AVL rotation techniques

Before jumping into the actual techniques, it s important to understand what balance factor is. Balance Factor The balance factor of a node is the difference in the heights of the left and right subtrees. The balance factor of every node in the AVL tree should be either +1, 0 or -1. 