a$.$ Consider the following Schedule S having $4$ transactions and are executed Concurrently.

The order of their operations are as follows:

S : r$1($x$),$ r$2($y$),$ w$2($y$),$ w$3($x$),$ r$3($z$),$ w$3($y$),$ r$1($z$),$ w$4($x$),$ w$3($z$),$ r$4($x$),$ r$4($z$),$ w$4($z$)$ c$1,$ c$2,$c$3,$ c$4$

Find if S is what serializable? Conflict or view? Draw graph if needed.

b$.$ Is the following recoverable or strict or cascadeless schedule?

r$2($x$),$ r$1($x$),$ w$1($x$),$ r$1($y$),$w$1($y$),$ c$1,$ w$2($x$),$ c$2$

r$1($x$),$ w$1($x$),$ r$2($x$),$ r$1($y$),$ w$2($x$),$ c$2,$ a$1$

r$1($x$),$ w$1($x$),$ r$2($x$),$ r$1($y$),$ w$2($x$),$ w$1($y$),$ a$1,$ a$2$

r$1($x$),$ r$2($x$),$ w$1($x$),$ r$1($y$),$ w$1($y$),$ c$1,$ w$2($x$),$ c$2$