"The good news from today is that one, he plans to return,two, he could return as early as this year, and three, he clearly has taken the first very visible step in the road to that return.

VOA: standard.2010.02.19

So this line or these lines of code up here are arguably constant time steps to say if N is less than 2 in return, that it will always take maybe one step, maybe two steps, some number of fixed CPU cycles.

如果N小于2并返回,那么这些行所对应的代码,通常只需要执行一步，或者两步，具体数字与CPU周期有关。

哈佛公开课 - 计算机科学课程节选