Max Dot Product with 0 Insertions

Given two arrays a[] and b[] of positive integers of size n and m respectively, where m ≤ n. You are allowed to insert zeros anywhere into the second array b so that its length becomes equal to n. The dot product of two arrays of equal length n is defined as: a[0]*b[0] + a[1]*b[1] + ... + a[n-1]*b[n-1]. Return the maximum possible dot product of the two arrays.