LeetCode-Rotate Function

Given an array of integers A and let n to be its length.

Assume Bk to be an array obtained by rotating the array A k positions clock-wise, we define a "rotation function" F on A as follow:

F(k) = 0 * Bk[0] + 1 * Bk[1] + ... + (n-1) * Bk[n-1].

Calculate the maximum value of F(0), F(1), ..., F(n-1).

Note:
n is guaranteed to be less than 10⁵.

Example:

A = [4, 3, 2, 6]

F(0) = (0 * 4) + (1 * 3) + (2 * 2) + (3 * 6) = 0 + 3 + 4 + 18 = 25
F(1) = (0 * 6) + (1 * 4) + (2 * 3) + (3 * 2) = 0 + 4 + 6 + 6 = 16
F(2) = (0 * 2) + (1 * 6) + (2 * 4) + (3 * 3) = 0 + 6 + 8 + 9 = 23
F(3) = (0 * 3) + (1 * 2) + (2 * 6) + (3 * 4) = 0 + 2 + 12 + 12 = 26

So the maximum value of F(0), F(1), F(2), F(3) is F(3) = 26.

Anlysis:

roateValue[i-1] = rotateValue[i] - (len-1)*A[i] + (sum-A[i])

Solution:

public class Solution {
    public int maxRotateFunction(int[] A) {
        if (A.length==0) return 0;
        if (A.length==1) return 0;
        
        int rotateValue = 0;
        int sum = 0;
        for (int i=0;i<A.length;i++){
            sum += A[i];
            rotateValue += i*A[i];
        }
        
        int maxValue = rotateValue;
        for (int i=A.length-1;i>=1;i--){
            rotateValue = rotateValue - (A.length-1)*A[i] + (sum-A[i]);
            maxValue = Math.max(maxValue,rotateValue);
        }
        return maxValue;
    }
}