Explanation : Insertion of an element into AVL requires O(log n) time.
To insert an element
1. Find the position, where to insert
2. After insertion, to satisfy AVL properly, we may need to perform rotation.
So, (1) take ‘log n time’ and (2) take ‘log n’ time.
Total time for inserting one element into AVL tree is
log n + log n = 2 log n ⇒ O (log n).
Now, To insert n2 elements ⇒ n2 log n
⇒ O(n2 log n)