Consider the following algorithm Algorithm XYZ(r,q,n) \ ,q,n are positive integers 1. if n=1 then return r 2. else - 3. if n is odd then return XYZ(r,q, n 1) + (n 1)q - 4. else return XYZ (r,q,n-1)-(n - 1)q a) What does the algorithm compute? b) What is the recurrence relation for the algorithm? c) What is the time complexity of the algorithm (solve the recurrence in part b).