Rotate Function

rotate_function.cpp

class Solution {
public:
    int maxRotateFunction(vector<int>& A) {
        int len = A.size();
        int sum = 0;
        int psum = 0;
        
        // sum
        for (int i = 0; i < len; ++i) {
            sum += A[i];
            psum += i * A[i];
        }
        
        int result = psum;
        for (int n = 1; n < len; ++n) {
            psum = psum + sum - len * A[len - n];
            result = max(psum, result);
        }
            
        return result;
    }
};