Consider a set 4 processes (P1,P2,P3,P4) with 3 units of R1, 4 units of R2, 3 units of R3 and 2 units of R4. Further, P1 holds 2 units of R1 and waits for 1 unit of R2. P2 waits for 2 units of R1 and holds 1 unit of R2, P3 holds 2 units of R3 and waits for 1 unit of R4, P4 holds 2 units of R3 and waits for 1 unit of R4. Construct the wait-for graph. Does the system have a deadlock? Justify your answer