什么是"O(1)访问时间"?意思是? [英] What does "O(1) access time" mean?
问题描述
我已经看到"O(1)访问时间"这个术语曾经表示迅速"，但是我不明白它的含义.我在同一上下文中看到的另一个术语是"O(n)访问时间".有人可以简单的方式解释这些术语的含义吗?
I have seen this term "O(1) access time" used to mean "quickly" but I don't understand what it means. The other term that I see with it in the same context is "O(n) access time". Could someone please explain in a simple way what these terms mean?
另请参见
- What is Big O notation? Do you use it?
- Big-O for Eight Year Olds?
推荐答案
您将要了解复杂性的顺序.
You're going to want to read up on Order of complexity.
http://en.wikipedia.org/wiki/Big_O_notation
简而言之，O(1)表示它花费恒定的时间，例如14纳秒或3分钟，无论集合中的数据量如何.
In short, O(1) means that it takes a constant time, like 14 nanoseconds, or three minutes no matter the amount of data in the set.
O(n)表示它花费的时间与集合的大小成线性关系，因此，两倍大小的集合将花费两倍的时间.您可能不想在其中一个对象中放入一百万个对象.
O(n) means it takes an amount of time linear with the size of the set, so a set twice the size will take twice the time. You probably don't want to put a million objects into one of these.
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