Dictionaries are implemented using a magic technique called hashing, which we'll look at a little bit later in the term, which allows us to retrieve keys in constant time.

散列法的内容,此方法可以让我们在线性,时间内检索到键,因此字典的大小并不重要了。

麻省理工公开课 - 计算机科学及编程导论课程节选

As I said, what we want to do is, we want to count the number of basic steps it takes to compute a computation as a function of input size.

我刚才提到了，我们要建立，一个根据输入大小的方法来计算,一个计算过程需要的时间,建立这个方法需要几步呢？

麻省理工公开课 - 计算机科学及编程导论课程节选

To get any location in memory, to get to any value of the list, I simply have to say which element do I want to get, I know that these things are stored in a particular size multiply that index by 4, add it to start, and then it's in a constant amount of time I can go to that location and get out the cell.

取得列表中的任何一个值,简单说来，想要取得列表中的任何元素,我知道这些元素存在特定的大小中,把下标乘以4，加到start上,然后定位到内存单元，并取出值就是固定的时间了,好的，如果元素以固定大小存储。

麻省理工公开课 - 计算机科学及编程导论课程节选