Maximum Absolute Difference

You are given an array of N integers, A1, A2 ,…, AN. Return maximum value of f(i, j) for all 1 ≤ i, j ≤ N.
f(i, j) is defined as |A[i] - A[j]| + |i - j|, where |x| denotes absolute value of x.

For example,

A=[1, 3, -1]

f(1, 1) = f(2, 2) = f(3, 3) = 0
f(1, 2) = f(2, 1) = |1 - 3| + |1 - 2| = 3
f(1, 3) = f(3, 1) = |1 - (-1)| + |1 - 3| = 4
f(2, 3) = f(3, 2) = |3 - (-1)| + |2 - 3| = 5

So, we return 5.

My solutions:

A = [-70, -64, -6, -56, 64, 61, -57, 16, 48, -98]


def maxArr(A):
    size = len(A)
    max_diff = 0
    start = 0
    end = 1

    while start < size:
        a1 = abs(A[start] - A[end])
        b1 = abs((start + 1) - (end + 1))
        abs_num = a1 + b1
        max_diff = max(max_diff, abs_num)

        if end < size - 1:
            end += 1
        else:
            start += 1
            end = 1

    return max_diff


print(maxArr(A))

This is my solution, but I failed to optimize my time complexity:

Best time complexity is O(N).

Good solutions:

https://www.geeksforgeeks.org/maximum-absolute-difference-value-index-sums/