某书店有一个收银员,该书店最多允许n个购书者进入。将收银员和购书者看做不同的进程,其工作流程如图5-2所示。利用PV操作实现该过程,设置信号量S1、S2和Sn,初值分别为0,0,n。则图5-2中a1、a2应填入(41),b1和b2应填入(42)。
A. V(S1)、P(S2)
B. V(Sn)、P(Sn)
C. P(S1)、V(S2)
D. P(S2)、V(S)
There was no immediate word on casualties in the latest violence in the former republic of the ex-Soviet Union, but witnesses to Friday's mayhem said more than 200 people were killed in gunfire after government troops confronted the huge demonstration.
When did the violence start?
A. Days ago.
B. On Thursday.
C. On Friday.
D. On saucy.