Let A[l:n] be an array of n distinct numbers. If i < j and A[i] > A[/], then the pair (i, j) is called an inversion of A. (See Problem 2-4 on page 47 for more on inversions.) Suppose that the elements of A form a uniform random permutation of (1,2,..., n). Use indicator random variables to compute the expected number of inversions.