https://projecteuler.net/
Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems.
The motivation for starting Project Euler, and its continuation, is to provide a platform for the inquiring mind to delve into unfamiliar areas and learn new concepts in a fun and recreational context.
https://cn.udacity.com/
https://www.coursera.org/
https://www.codecademy.com/
其中，Udacity和Coursera提供课程的付费版本。
原文：https://www.cnblogs.com/luffystory/p/9313415.html