The 18th season of COCI is starting soon! The first round will be held this Saturday, November 4th at 13:00 UTC. You can access the judging system here. If you are not familiar with COCI contest format, we encourage you to read the announcement.
Feel free to discuss the problems in the comment section after the contest ends.
Hope to see you and good luck!
Update: the round has been moved to start 1 hour earlier because of the Meta Hacker Cup.