The reason I'm going to show you this flow chart, I'm going to do one other example in a second, but I want to show you a comparison.

我稍后还会给大家讲另外一个例子，我给大家看这个流程图的原因，是我想给大家一个对比。

麻省理工公开课 - 计算机科学及编程导论课程节选

And the reason I want to show you this is to notice that the recursion can be doubled.

如果我来写斐波那契数列你可以看看这儿,原因是我想让你看看这部分的递归可以翻倍。

麻省理工公开课 - 计算机科学及编程导论课程节选