n*********y
发帖数: 41 | 1 原帖在这里： http://www.mitbbs.com/article_t1/JobHunting/33285661_0_1.html
今天跟FB专门做privacy setting一美国大牛又聊到了这个问题，跟他讲了之前大家讨
论的“post to friends' timeline”的想法。他的回复是：
This can be done simpler, without any extra writes.
A hint: You are thinking about the problem as "How to check if C is a friend
of friends of A". But it is possible to rephrase the question in an other
way which will make the problem much simpler to solve.
大家怎么看？
PS： 再把题目贴一下
privacy setting. 说是每个user有一个friend
list, user可以发Post, 问如何设计Ouser friends的friends可见,时间复杂度O(N) | x***y
发帖数: 633 | 2 some sort of variation of TTL, originally 2, decrease by 1 in each step? But
it may need to dedup in some cases | n*********y
发帖数: 41 | 3 这个大牛只给了我思路，他和我的面试官是一个组的，我一问他就知道这个问题，大概
是他们私下讨论过的。所以他的hint应该是没有问题的。大家对这个思路有什么想法没
有？ | r*v
发帖数: 12 | 4 check intersection of F(a) and F(c)? |
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