All problems in this round were created and prepared by a team of all-Vietnamese setters: MofK, I_love_tigersugar, UncleGrandpa, ngkan. This is the first Vietnamese Div1 round. We tried to make both the problems and the statements interesting and hope that you will enjoy them!
There is an interactive problem in the round. You can read the guide for interactive problem here.
We would like to give a lot of thanks to:
MikeMirzayanov for the amazing platforms Codeforces and Polygon.
arsijo for excellent coordination and many valuable advice for the round.
Our team of testers: MikeMirzayanov, KAN, tanphatls987, Kuroni, AomeII, ngfam, goodthingstaketime_._, dush1729, lannh2207, nhakhoa, Sumeet.Shirgure, BledDest, NatInTheHat, AlexPop28 for testing the round and give feedback about the problems.
We wish you an exciting round!
UPD: The message from MikeMirzayanov. If the issue heavily affected you and you want the round to be UNRATED for you, you can fill the appeal form by the link: https://codeforces.com/userForm/f0458e24fa295 Please do not fill it just in case. Be honest, fill in only if the problem broke your participation in the contest. Mike.
UPD: There will be five problems for Division 1 and six problems for Division 2. The score distribution is as follows:
Division 1: 750 — (500 + 750) — 1500 — 1750 — 2500
Division 2: 500 — 1000 — 1500 — 1750 — (1000 + 1250) — 2750
UPD2: : Thanks for participating! Congratulations to the winners!!!
Div. 1: Top 5 are also the only 5 contestant managed to solve all problems!
Honorable mention: Justice_for_721-incident for solving problem E in just 31mins!
MbahSA1937 (solved all problems!)
mintwhale (solved all problems!)
UPD3:Editorial is out!