-
Codeforces codeforces.com
-
Zhejiang University (ZJU) acm.zju.edu.cn
-
Peking University (PKU) acm.pku.edu.cn/JudgeOnline
-
Hangzhou Dianzi University (HDU) acm.hdu.edu.cn
-
University of Virginia (UVA) uva.onlinejudge.org
-
Programming Ability Test (PAT) patest.cn/contests
-
Lanqiao (蓝桥杯) lx.lanqiao.cn
Tips: If you are unable to access these OJs due to server errors, use Virtual Judge (vjudge.net) instead to search for a certain problem.
Any improvement to existing solutions or new solutions are welcome. Create a pull request when you are done.
If you have any questions, use issue to communicate with the owner.