Codeforces Round #500 (based on EJOI)

Revision en8, by 300iq, 2018-07-30 15:45:06

Hello everybody!

On July 28 and 30 will take place tours of EJOI — individual programming competition for juniors, held under the rules of the International Olympiad in Informatics.

EJOI consists of the most interesting and hard problems that are proposed by a wide community of authors, and that is why we decided to give you an opportunity to crack the complete problemset of the contest. During the second tour of Olympiad, we are going to conduct a rated Codeforces round based on problems of both days of our Olympiad.

We kindly ask all the community members that are going to participate in the competition to show sportsmanship by not trying to cheat in any manner, in particular, by trying to figure out problem statements from the onsite participants. If you end up knowing some of the problems of EJOI (by participating in it, from some of the onsite contestants or in any other way), please do not participate in the round. We also ask onsite contestants to not discuss problems in public. Failure to comply with any of the rules above may result in a disqualification.

The round will happen at Jul/30/2018 11:15 (Moscow time) and will last for 2.5 hours. There will be 6 problems in each division.

The tasks of the round were invented and prepared by tourist, PavelKunyavskiy, niyaznigmatul, 300iq, GlebsHP, pashka, qoo2p5, VArtem, demon1999, Flyrise, ifsmirnov, isaf27, yeputons, cdkrot.

Also thanks for testing never_giveup, vintage_Vlad_Makeev, izban, GoToCoding, Egor, doreshnikov, Sert, disa, wrg0ababd, kraborak, Nebuchadnezzar.

And, of course, thanks to MikeMirzayanov for great systems Codeforces and Polygon.

Good luck everybody!

UPD: Congratulations to winners!


1) Um_nik

2) LHiC

3) dacin21

4) ksun48

5) Swistakk


1) UnproductiveGuy

2) WaldarDoppen

3) IHaveHir

4) cly_none

5) Shadi.Gh


  Rev. Lang. By When Δ Comment
en8 English 300iq 2018-07-30 15:45:06 395
ru9 Russian 300iq 2018-07-30 15:44:35 388 Мелкая правка: '\n\n**UPD::** поздра' -> '\n\n**UPD:** поздра'
en7 English 300iq 2018-07-29 17:21:21 33 Tiny change: 'g [user:gri' -> 'g [user:grumpy_gordon], [user:gri'
ru8 Russian 300iq 2018-07-29 17:21:08 33 Мелкая правка: 'в [user:gri' -> 'в [user:grumpy_gordon], [user:gri'
en6 English 300iq 2018-07-29 00:11:51 28 Tiny change: 'ing [user:izb' -> 'ing [user:gritukan], [user:izb'
ru7 Russian 300iq 2018-07-29 00:11:18 28 Мелкая правка: 'ров [user:izb' -> 'ров [user:gritukan,2018-07-27], [user:izb'
en5 English 300iq 2018-07-27 13:30:21 27 Tiny change: ' by [user:Pav' -> ' by [user:tourist,2018-07-27], [user:Pav'
ru6 Russian 300iq 2018-07-27 13:30:08 27 Мелкая правка: 'ены [user:Pav' -> 'ены [user:tourist,2018-07-27], [user:Pav'
en4 English 300iq 2018-07-27 12:37:42 7 Tiny change: 'of [EJOI](ejoi2018.o' -> 'of [EJOI](http://ejoi2018.o'
ru5 Russian 300iq 2018-07-27 12:37:25 7 Мелкая правка: 'ры [EJOI](ejoi2018.o' -> 'ры [EJOI](http://ejoi2018.o'
en3 English 300iq 2018-07-27 11:44:17 0 (published)
ru4 Russian 300iq 2018-07-27 11:33:14 0 (опубликовано)
en2 English 300iq 2018-07-27 11:19:32 25 Tiny change: 'ing [user:GoT' -> 'ing [user:izban,2018-07-27], [user:GoT'
ru3 Russian 300iq 2018-07-27 11:19:22 25 Мелкая правка: 'ров [user:GoT' -> 'ров [user:izban,2018-07-27], [user:GoT'
ru2 Russian 300iq 2018-07-27 11:11:14 10 Мелкая правка: 'ime:1012] по Москве и продлит' -> 'ime:1012] и продлит'
en1 English 300iq 2018-07-27 11:11:02 2063 Initial revision for English translation (saved to drafts)
ru1 Russian 300iq 2018-07-27 11:02:50 2080 Первая редакция (сохранено в черновиках)