Counting inversions in an array

Question

I\'m designing an algorithm to do the following: Given array A[1... n], for every i < j, find all inversion pairs such that A[i] > A[j]

Answer 1

Check this out: http://www.cs.jhu.edu/~xfliu/600.363_F03/hw_solution/solution1.pdf

I hope that it will give you the right answer.

• 2-3 Inversion part (d)
• It's running time is O(nlogn)