答案:选一个囚犯出来负责关灯,其余的负责开灯,而且每人只能开一次,当这个囚犯关够99次的时候,就知道所有的囚犯都来过院子了。
3 J$ W. k3 a \7 K* L$ Gtvb now,tvbnow,bttvbtvb now,tvbnow,bttvb5 t: ?5 G% U, X) _
i don't get it.. how to pick someone to record it.. when there is only 1 person allow to go out each day..and he/she will lock up later |