Codeforces Round #644 (Div. 3)

Revision en8, by Supermagzzz, 2020-05-24 18:49:04

Hello, Codeforces!

We have planned this round as a Div. 4, but testing showed us, that problems are more suitable for Div. 3. Therefore, instead of the previously announced Div. 4 we will hold Div. 3 round.


Hello! Codeforces Round #644 (Div. 3) will start at May/24/2020 16:35 (Moscow time). You will be offered 8 problems with expected difficulties to compose an interesting competition for participants with ratings up to 1600. However, all of you who wish to take part and have a rating 1600 or higher, can register for the round unofficially. The round will be hosted by rules of educational rounds (extended ACM-ICPC). Thus, during the round, solutions will be judged on preliminary tests, and after the round it will be a 12-hour phase of open hacks. I tried to make strong tests — just like you will be upset if many solutions fail after the contest is over.

You will be given 8 problems and 2 hours to solve them.

Note that the penalty for the wrong submission in this round (and the following Div. 3 rounds) is 10 minutes.

Remember that only the trusted participants of the third division will be included in the official standings table. As it is written by link, this is a compulsory measure for combating unsporting behavior. To qualify as trusted participants of the third division, you must:

  • take part in at least two rated rounds (and solve at least one problem in each of them),
  • do not have a point of 1900 or higher in the rating.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you.

The problems for this round were invented by MikeMirzayanov and prepared by me and Stepavly

Thanks to MikeMirzayanov for platforms and coordination of our work. Thanks to antontrygubO_o, iankury, bfs.07, kocko, Ilya-bar, arsijo, pashka, Gassa, neal, vovuh for help in round preparation and testing the round.

Good luck!


UPD: Editorial is out


  Rev. Lang. By When Δ Comment
en8 English Supermagzzz 2020-05-24 18:49:04 68
ru18 Russian Supermagzzz 2020-05-24 18:48:06 70
en7 English Supermagzzz 2020-05-24 15:55:55 25 Tiny change: '020-05-22]' -> '020-05-22], [user:vovuh,2020-05-22]'
ru17 Russian Supermagzzz 2020-05-24 15:55:24 25 Мелкая правка: '020-05-22]' -> '020-05-22], [user:vovuh,2020-05-22]'
en6 English Una_Shem 2020-05-23 10:35:27 3 Tiny change: ' invented [user:Mik' -> ' invented by [user:Mik'
ru16 Russian Supermagzzz 2020-05-23 02:07:47 7
en5 English Stepavly 2020-05-22 23:13:31 0 (published)
ru15 Russian Stepavly 2020-05-22 23:13:16 0 (опубликовано)
en4 English Stepavly 2020-05-22 23:12:28 134 (saved to drafts)
ru14 Russian Stepavly 2020-05-22 23:11:59 129 (сохранено в черновиках)
en3 English Supermagzzz 2020-05-22 22:43:28 0 (published)
ru13 Russian Supermagzzz 2020-05-22 22:42:51 0 (опубликовано)
ru12 Russian Supermagzzz 2020-05-22 22:42:19 43
en2 English Supermagzzz 2020-05-22 22:41:56 57
ru11 Russian Supermagzzz 2020-05-22 22:39:57 38
ru10 Russian Supermagzzz 2020-05-22 22:37:01 12
en1 English Supermagzzz 2020-05-22 22:33:55 2471 Initial revision for English translation (saved to drafts)
ru9 Russian Supermagzzz 2020-05-22 22:26:52 0 Мелкая правка: 'orces!\n\nЭтот раунд' -> 'orces!\n\nМы, пешки [user:Миразаянова] готовыЭтот раунд'
ru8 Russian Supermagzzz 2020-05-22 22:26:26 32
ru7 Russian Supermagzzz 2020-05-22 22:25:31 2 Мелкая правка: 'Удачи!\n\n</almost-copy-pasted-part>' -> 'Удачи!\n\n\</almost-copy-pasted-part\>'
ru6 Russian Supermagzzz 2020-05-22 22:25:21 4
ru5 Russian Supermagzzz 2020-05-22 22:25:00 2
ru4 Russian Supermagzzz 2020-05-22 22:23:51 10 Мелкая правка: 'r:Stepavly,2019-01-01]\n\nСпаси' -> 'r:Stepavly]\n\nСпаси'
ru3 Russian Supermagzzz 2020-05-22 22:23:13 121
ru2 Russian Supermagzzz 2020-05-22 22:22:01 23 Мелкая правка: 'trygubO_o][user:iank' -> 'trygubO_o] [user:iank'
ru1 Russian Supermagzzz 2020-05-22 22:21:43 2300 Первая редакция (сохранено в черновиках)