오랜만이에요, 코드포스! (Long time no see, Codeforces!)
I'd like to welcome all of you to Codeforces Round #688 (Div. 2)! The contest will start at Dec/04/2020 16:05 (Moscow time), and it is rated for all participants with ratings under 2100. Note the semi-unusual start time.
You will be given 6 problems and 2 hours and 15 minutes to solve them. The score distribution will be announced soon.
All problems are prepared by me, with a lot of help from the testers
making me realize that my solutions are dumb.
Thanks to Green55, JooDdae, cs71107, YeongTree, IntoTheNight, jh05013, 351F44, 39dll, akaman123, Ku_Top, sonjaewon, slah007, jooncco, and kalki411 for testing the round, and especially xiaowuc1 for helping polish English statements as well. I would also like to thank 300iq for round coordination, and MikeMirzayanov for the great Codeforces and Polygon system.
See you in the round!
UPD: The scoring distribution is 500 — 1000 — 1500 — 2000 — 2500 — 3500.
UPD 2: The round is finished. Thanks for your participation! I'm sorry about underestimating the difficulty of problem B, but I hope you still enjoyed the problems! The editorial will be posted in a minute.
UPD 3: The editorial is out!
UPD 4: Congratulations to the winners!
Unofficial Div. 1