Hey all!

We would like to invite you all to an online replay contest for UWCOI 2021. UWCOI 2021 is an OI-style contest hosted by the Computing Society of UWCSEA Dover which will be used to select members for the UWCSEA Dover team for the Singapore National Olympiad in Informatics for this year. It is also participated-in by several other schools in Singapore. The online replay contest will be held as a round rated for both divisions on CodeChef.

We have also held UWCOI 2020 around a year ago -- you can check out the problems here if you wish and get a feel for the contest.

Here are some details:

• Time: Saturday, 19 December, 2020, 21:00 hrs IST (Indian Standard Time). Please check your local timezone here.
• Contest Format: 7 OI-style tasks (tasks have subtasks) in 3 hours.
• There is no time penalty for non-accepted verdicts; however, time will be used as the tiebreak.
• The contest is rated for both divisions (all ratings).
• There may or may not be interactive questions.
• The writers are smjleo, astoria and kimbj0709.
• The contest is hosted on CodeChef here.

We hope you enjoy the contest!

Update: We would like to thank our testers from CodeChef: Akash Whiplash99 Bhalotia, Aryan Aggu_01000101 Agarwala, Daanish 7dan Mahajan, Jatin jtnydv25 Yadav and Smit l_returns Mandavia for helping us out with polishing statements and testdata, as well as giving us valuable feedback.

I had a revelation during my biology exam: every vertex in an unrooted tree should be called a "seed"; it has the potential to become a root, but it's not the root yet.