Test Case #$3$:

R R R

$123$

P$1$ n x w $//$ P$1$ is x$-$holding R$2,$ waiting for R$3.$

P$2$ x n w $//$ P$2$ is x$-$holding R$1,$ waiting for R$3.$

P$3$ n w x $//$ P$3$ is x$-$holding R$3,$ waiting for R$2.$