I first had a list of size 8, then 4, then 2, but then I had another problem of size 2.

首先是一个有8个元素的序列，接着变成了4个元素，接着2个元素，然后我就碰到了有2个元素的另一个问题。

哈佛公开课 - 计算机科学课程节选

Here's the problem. How do I get to the nth- er, the k'th element in the list, in this case?

如何找到第n个元素呢-,在这里，如何找到第k个元素呢？

麻省理工公开课 - 计算机科学及编程导论课程节选