please answer the question

Assume that there are three processes P1, P2, P3and P4 and four resources R1, R2, R3 and R4. The processes make the requests for resources in the following order: PI requests RI P2 requests R2 P3 requests R3 P4 requests R4 Pl requests R2 P2 requests R3 P3 requests R4 P4 requests RI Assume that there is only one instance of resources RI, R2, R3 and R4. Draw a resource allocation graph and find out if the above processes will deadlock or no What are the four necessary conditions for a deadlock to happen