Let T1 have the operations r(y), w(y) and T2 have the operations r(y), w(y), r(x), w(x). Consider the different possible concurrent schedules for T1 and T2. From among these possible schedules

(a) Give two examples of schedules which are conflict serializable (but not serial). Explain why these are conflict serializable by drawing the precedence graph; these should not have a cycle. No other explanation needed.

(b) Give two examples of schedules which are not conflict serializable. Explain why these are not conflict serializable by drawing the precedence graph; these should have a cycle. No other explanation needed.