This is the third round of the 2021 series of Codeforces Global Rounds. The rounds are open and rated for everybody.
The prizes for this round are as follows:
- 30 best participants get a t-shirt.
- 20 t-shirts are randomly distributed among those with ranks between 31 and 500, inclusive.
The prizes for the 6-round series in 2021:
- In each round top-100 participants get points according to the table.
- The final result for each participant is equal to the sum of points he gets in the four rounds he placed the highest.
- The best 20 participants over all series get sweatshirts and place certificates.
Thanks to XTX, which in 2021 supported the global rounds initiative!
Problems for this round are set by cip999 and me. Thanks a lot to the coordinator antontrygubO_o, to the testers gamegame, ajit, golions, skydogli, McDic, rabaiBomkarBittalBang, nweeks, Marckess, HenriqueBrito, gratus907, bWayne, zscoder, TheOneYouWant, and to MikeMirzayanov for the Codeforces and Polygon platforms.
You will be given 9 problems and 2 hours 45 minutes to solve them.
The scoring distribution is 250-500-1000-1000-1500-1500-2500-2750-3750.
This scoring distribution is not particularly strange, unusual or deep. There is no demoralization tactic, no baiting tactic, no need to give a gazillion points to the last problem. It is simply the scoring distribution that we consider more adequate for the problemset. 250 is not particularly low for a first problem, 3750 is not particularly high for a last one. Everything is normal.
Please, do not waste your time thinking about the scoring distribution... watch the Olympic Games instead!
Good luck and see you in the standings!
UPDATE 1: Thank you very much for participating, we hope you liked the problems (and sorry to top contestants for giving a not-so-fresh problem I).
Here you can find the editorial (with a bit of behind-the-scenes, some obscenely wrong preditions, and hints for all the problems).
UPDATE 2: Congratulations to the winners!