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。
! O s% e- f, O( H- n8 Ktvb now,tvbnow,bttvb
. I+ T+ ?6 W! E! S) _ ptvb now,tvbnow,bttvbi 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 |