请教问题+狗家两次店面

请教:google domain knowledge onsite interview是怎么考察?

店面1:q1: string有没有重复character?
q2: given a B-tree, find all leaves.
店面2: given the grid of go, check whether the specified spot is survived . The strategy is the same as GO game. “活眼”

timeline : got the second phone notice through phone in one week after the first phone interview was done.
got the onsite notice after 2 days after the second phone interivew was done. 我周三店面后,觉得failed,周五看HR邮件,没有回。周一收到HR第二封约电话的邮件。下午知道店面过了,进入onsite

请问楼主,围棋那道题,怎么定义活棋和死棋?

given a B-tree, find all leaves. 是 里扣伞流流嘛?