It's like you have a social security number or other ID number, which positively--there might be another person with the same name as you, God forbid, but you at least have your own number, which is guaranteed to be unique to you.

就好比社保号,或者其他身份号码,很有可能,有另外一个人,和你重名,希望这不要发生,但你至少有唯一的识别号,用于区分自己和他人

耶鲁公开课 - 金融市场课程节选

So halfway is the right thing to do, because at each step, I'm guaranteed to throw away at least half the list. Right? And that's nice.

一半以上的元素，对不对？，这很棒，好，大家猜猜这个算法的增长率是多少？,为什么？太对了。

麻省理工公开课 - 计算机科学及编程导论课程节选