3. Apply the shifting bottleneck heuristic for the makespan objective in the following instance of the job shop problem. Job 1 2 3 Machine sequence 2, 3, 4 1, 1, 2, 4, 3 3, 1, 2, 4 Processing Times P119, P218, P31= 4, P41 = 4 P12=5, P22=6, P42 = 3, P32= 6 P3310, P134, P23 = 9, p43 = 2 a) Show the routing constraints on a network diagram. (5 points) b) Produce the first feasible schedule by the shifting bottleneck heuristic. Clearly show your work in each step of the algorithm. (30 points)