先加入：
https://www.coursera.org/learn/algorithms-part1
其中 Welcome 给出了 BooKSite
Our booksite, which is open to everyone and contains a wealth of supplementary information,
including synopses of the textbook and Java code that you will be using throughout the course.
使用的教材是：
解决 Coursera 无法看视频问题：
1. 用管理员权限记事本打开host文件
文件位置：C:\Windows\System32\drivers\etc\HOSTS
2. 将如下内容复制到文件末尾
52.84.246.90 d3c33hcgiwev3.cloudfront.net 52.84.246.252 d3c33hcgiwev3.cloudfront.net 52.84.246.144 d3c33hcgiwev3.cloudfront.net 52.84.246.72 d3c33hcgiwev3.cloudfront.net 52.84.246.106 d3c33hcgiwev3.cloudfront.net 52.84.246.135 d3c33hcgiwev3.cloudfront.net 52.84.246.114 d3c33hcgiwev3.cloudfront.net 52.84.246.90 d3c33hcgiwev3.cloudfront.net 52.84.246.227 d3c33hcgiwev3.cloudfront.net
3. 打开命令行，输入如下命令
ipconfig/flushdns