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。
. W* _: _$ I1 X6 Z2 ptvb now,tvbnow,bttvb. s* H6 _5 ~0 L7 }+ }- H/ Y: Q3 d! H
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 |