Counting inversions 

Excellent explanation! This is the BEST explanation of how to count inversions using a merge sort type algorithm that I have found!

If courses are bollywood, NTPEL is the Irfan Khan of it.

Very good straight to the point and clear

sir countR,R should be mergesortcount(A,mid+1,right).i have a dought.correct me if i am wrong

Very nice explanation. Leetcode 493 is based on this.

superb explanation

Thanks a lot sir!

What I don't understand is the part : sort and count inversions in L and R. I mean since you sort L and R already, the count of inversions in either L or R would be 0, isn't it?