What I though I'd do is just tease you with some visuals if you haven't gotten to the point of playing with the staff solution so the themes of problem set 3 are two-fold.

如果你们还没达到使用解决方案的程度,那现在我能做的就是用一些图形为你们梳理一下,习题集3的主题,是两方面的。

哈佛公开课 - 计算机科学课程节选