Example: (Single rotation into AVL tree, while a new node is inserted into the

AVL tree (LL Rotation))

Figure: LL Rotation

The rectangles marked A, B & C are trees of equivalent height. The shaded rectangle stands for a new insertion into the tree C. Before the insertion, the tree was balanced, for the right child was taller than the left child through one.

The balance was broken while we added a node into the right child of 7, as the difference in height became 7.

To fix the balance we make 8 the new root, make c the right child move the old root (7) down to the left together with its left sub tree A and finally move sub tree B across and make it the new right child of 7.