a. Solve the rod-cutting problem for the attached set of prices. (p1, p2, p3, p4, p5, p6, p7) = (1, 3, 4, 6, 8, 12, 15). Show the final r structure and s structure. b. Someone solved an instance of the rod-cutting problem the following s array. (s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11, s12) = (1, 2, 1, 2, 5, 2, 5, 5, 4, 9, 5, 8). Using only the s array, determine the optimal solution to the problem instance.