4. Consider the following algorithm. ALGORITHM Mystery(n) //Input: A nonnegative integer n SEO for i 1 to n do SES +i* i return S a. What does this algorithm compute? b. What is its basic operation? c. How many times is the basic operation executed? d. What is the efficiency class of this algorithm? e. Suggest an improvement, or a better algorithm altogether, and indicate its efficiency class. If you cannot do it, try to prove that, in fact, it cannot be done