The China team selection ended today, the top 4 are:

Xu Tingqiang (Rebelz),

Cheng Siyuan (cnnfls_csy),

Qi Langrui (Laurie) and

Liu Yiping (He_Ren).

They will participate in IOI2023. Good luck!

Hello Codeforces!

feecIe6418 and I are glad to invite you to Codeforces Round 729 (Div. 2) which will start on Jul/03/2021 16:05 (Moscow time). Note the unusual start time of the round.

The contest will last for two hours, and you will have five tasks to solve. The tasks are prepared by feecIe6418 and me. This round is rated for participants whose rating is not higher than 2099.

We would like to thank:

• Aleks5d for coordinating and helping us with the problems.

• dorijanlendvaj, waaitg, Imakf, alexX512, Akulyat, talibmohd, hbarp, andr0901, nnv-nick, Delmos, kassutta, wxhtzdy, 4qqqq, for testing the problems and providing useful feedback.

• amgfrthsp for translating the statement

• finally, MikeMirzayanov for great platforms Codeforces and Polygon!

It's the second time we hold our contest, our previous round Codeforces Round 670 (Div. 2).

We tried our best to make the statements short and clear, pretests strong and problems interesting. We hope you like the problems!

Score distribution will be announced shortly before the round.

Score distribution: 500-1250-1500-2000-(2000+1000)

Editorial is published Editorial

Congratulation to the winners:

Div1+Div2:

1.Nilou_

2.244mhq

3.jiangly

4.Benaive

5.Ormlis

Div2:

1.Nilou_

2.Benaive

3.hehezhouyyds

4.TuNormie04

5.SoilCrystal

I took part in the Codeforces round yesterday, and just now I received a message saying my code coincides with someone else's. I didn't know the person at all. I solved the problem a lot earlier than him, and I didn't share my code to anyone or anywhere. I think it's just a coincidence because the solution is short and the code is simple. Could you please take a look into this?MikeMirzayanov

Submissions:113994230 114020895

Could you please reply after seeing this post MikeMirzayanov, thanks!

Upd: fixed author's solution links.

Sorry for the slow Editorial, I am new using Polygon.

Special thanks to TechNite for his help.

About one hour before the contest Retired_cherry found the same problem, then we changed it to $$$k=4$$$ and he found another same one again. We are running out of time so we didn't have time for a new one, so we changed $$$k$$$ to $$$5$$$. But we didn't know there is still a similar problem. Sorry again.

idea:gyh20 solution:gyh20 tutorial:TechNite

Jury solution:92671575

idea: feecIe6418 solution:feecIe6418 tutorial:feecIe6418

Jury solution:92671590

idea:gyh20 solution:gyh20 tutorial:feecIe6418

Jury solution:92671713

idea:isaf27 solution:gyh20 tutorial:TechNite

Jury solution:92671763

idea:gyh20 solution:gyh20 tutorial:gyh20

Jury solution:92671740

I am trying to make problems using Polygon,but I am having problems with pictures.

Can anyone tell me how to add a picture to the problem in Polygon? I am not good at Latex.

Thank you very much.