Dear user,

We are so happy that you have come to the COJ.

Here you may test and improve your skills by trying to solve problems in the 24 hour archive or taking part in real contests and practice contests. First of all, you should read the FAQ carefully. Then, you can choose a problem from the set, solve it in any of the available programming languages, submit your solution, check the judgments and look up your user in the standings. Please, contact us if you want to publish your own problems, hold programming contests or comment on anything related to this system.

Thank you and have fun!

Best regards, COJ Development Team (CDEVT).