[LeetCode]--396. 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.

用F(k)=F(k-1)-(n-1)*end&