We saw some quadratic algorithms, typically those are things with multiple nested loops, or iterative or recursive calls, where you're doing, say, a linear amount of time but you're doing it a linear number of times and so it becomes quadratic, and you'll see other polynomial kinds of algorithms.

我们看过一些平方算法，他们一般进行了多次嵌套循环,或者递归迭代调用，对一个线性操作调用线性次,这样就变成平方次了,以后你们能看到,一些多项式算法。

麻省理工公开课 - 计算机科学及编程导论课程节选

And those are two things that you'd like to do with every looping construct you write: you'd like to be able to assure yourself that they will always terminate, and then the second thing you'd like to do, is to assure yourself that it does give you back a reasonable answer.

就是现在我有了能去检查程序,是不是做了正确的操作的能力：,这就是你们在写每个循环程序的时候,都要注意的两个事情：,第一件事情是要确保程序可以终结，第二件你要做的事情,就是要确保程序返回了正确的答案。

麻省理工公开课 - 计算机科学及编程导论课程节选

Because I keep counting down each time around-- mostly I've got to unload this candy which is driving me nuts, so-- thank you.

因为我每次循环b减了,我一共要执行这个循环b次,所以这里我们一共执行了3b次基本操作。

麻省理工公开课 - 计算机科学及编程导论课程节选

b times. So I've got to go 3 b steps. All right I've got to go through the loop b times I've got three steps each time, and then when I pop out of the loop, I've got two more steps. All right I've got the initiation of answer and the return of it.

好，我一共执行了b次循环,每次循环内部进行了三次基本操作,当跳出循环后还有两个基本操作，因此这个初始的答案就是,2+3b次基本操作,来完成这个循环。

麻省理工公开课 - 计算机科学及编程导论课程节选