Hello Codeforces!

We have a pleasure to invite you to Codeforces Round #647 (Div. 1) and Codeforces Round #647 (Div. 2). This round will take place on Jun/04/2020 17:35 (Moscow time). In both divisions, you will have 2.5 hours to solve 6 problems. Three of them will be shared.

The problems for this round were prepared by MicGor, Grzmot, Okrut and me.

We would like to thank everyone who made this round possible:

• budalnik for the excellent coordination;

• Lewin, sstrong for invaluable advice and extensive testing;

• KrK, yarek, -is-this-fft-, w0nsh, Marckess, Ari, Fortin, Dup4, craborac, 300iq, Sumeet.Shirgure, HIR180 for taking the time to test and providing useful feedback;

• MikeMirzayanov for great platforms Codeforces and Polygon.

We hope you will enjoy the problem set! Good luck!

UPD: Score distribution:

• Div 1: $$$500$$$ $$$-$$$ $$$1250$$$ $$$-$$$ $$$2000$$$ $$$-$$$ $$$2500$$$ $$$-$$$ $$$3000$$$ $$$-$$$ $$$3500$$$
• Div 2: $$$500$$$ $$$-$$$ $$$1000$$$ $$$-$$$ $$$1500$$$ $$$-$$$ $$$2000$$$ $$$-$$$ $$$2750$$$ $$$-$$$ $$$3500$$$

UPD: Editorial

UPD: Congratulations to the winners!

Div. 1:

• tourist
• Um_nik
• boboniu
• ecnerwala
• maroonrk

Div. 2

• rainboy
• Charbel
• icypiggy
• _khushi_
• KPATKOBPEMEHHOCTb

Below is a message for you from MikeMirzayanov:

With this round, we want to say thank you to Algo Muse for the significant contribution and support!

Algo Muse is an educational site that conducts online algorithmic contests in pen-and-paper style (no coding). It was originally started to help students prepare for theory qualifiers for graduate admissions. At present, the problems have a broader appeal, though occasionally an odd problem may require knowledge of linear algebra, probability, or group theory. The website is maintained by former students of IIT Bombay. To find out more, visit their website or their twitter account.