AWS EC2 Amazon Linux AMI 修改 hostname

AWS EC2 在使用 Amazon Linux AMI 创建服务器之后,服务器默认的 hostname 是内网 ip 地址,这样的 hostname 不是很友好,需要修改:

将第二行的 HOSTNAME 改成想要的 hostname ,然后重启服务器即可。

 

A beginner’s guide to Big O notation

(原文:https://rob-bell.net/2009/06/a-beginners-guide-to-big-o-notation/

Big O notation is used in Computer Science to describe the performance or complexity of an algorithm. Big O specifically describes the worst-case scenario, and can be used to describe the execution time required or the space used (e.g. in memory or on disk) by an algorithm.

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