Well I'm going to suggest that what I did was I really traded space for time. It makes me sound like an astro physicist somehow right?

困难在哪里？我在这里是如何权衡的？,我在这里所做的就是用空间换时间,这让我听起来像一个天体物理学家，是不是？

麻省理工公开课 - 计算机科学及编程导论课程节选