All right? If you run it, you have a sense of the upper bound, about how much time it's going to take to do this computation, so you're not going to get surprised by something showing up.

第一，这样做意味着没有意外了对不对？,你去运行程序,你已经大致知道运行时间的上限了，因此发生任何事情,你都不会吃惊了。

麻省理工公开课 - 计算机科学及编程导论课程节选