91Ó°ÊÓ

Refer to a project consisting of 11 tasks (A through \(K\) ) with the following processing times (in hours): \(A(10), B(7), C(11), D(8), E(9), F(5), G(3), H(6), I(4)\) \(J(7), K(5)\). (a) A schedule with \(N=3\) processors produces finishing time \(F i n=31\) hours. What is the total idle time for all the processors? (b) Explain why a schedule with \(N=3\) processors must have finishing time \(F i n \geq 25\) hours.

Explain why, in any digraph, the sum of all the indegrees must equal the sum of all the outdegrees.