Codeforces Round #420 (Div. 2)

Revision en7, by send_nodes, 2017-06-26 00:16:00

Hi everyone!

It's the round you've been waiting for... Codeforces Round #420 (Div 2). It will take place tomorrow, 25 June 2017, at 17:35 MSK. As always, Div. 1 participants are encouraged to join out of competition. The round will be rated for Div. 2 participants and will have 5 problems to be completed in 2 hours.

I wouldn't be able to create this round without the help of many people: KAN for lots of help in preparing the contest, gainullin.ildar and Alladdin for testing and providing feedback, and as always MikeMirzayanov for the Codeforces and Polygon platforms.

This will be my second contest, and I'm glad to get such a nice round number :). Hopefully, you'll find the problems interesting. Of course, you should read all the problems so you can solve problems you find easy or interesting.

To excite some and disappoint others, the round theme will have nothing to do with the number 420. Instead, continuing the anime themes of the last two rounds, round #420 will feature mad scientist Rintaro Okabe (don't read spoilers!) from the anime Steins;Gate. Statements will not contain any spoilers, but you might find the problems slightly more amusing if you've watched the series. Of course, you should watch the series if you havent :)!

As per Codeforces tradition, scoring distribution will be announced shortly before the contest. Good luck, and I hope you can help Okabe with all 5 tasks :D!

Scoring is standard: 500-1000-1500-2000-2500!

Update: Sorry for delays.

Update: Editorial is here:

I really apologize for the issues during the round. It's upset a lot of people and I should have taken more care. Hopefully you won't hold this against Okabe or Steins;Gate anime :P

Here are the contest winners! Congratulations!

Div. 1

  1. nuip
  2. uwi
  3. sugim48
  4. xumingkuan
  5. HellKitsune

Div. 2

  1. Parachutes
  2. Possessed_by_Phoenix
  3. visitWorld
  4. y553546436
  5. a_student_follower

Thanks for participation everyone! Hope to write more problems in the future (without bugs)!


  Rev. Lang. By When Δ Comment
en7 English send_nodes 2017-06-26 00:16:00 94
en6 English send_nodes 2017-06-25 22:27:01 28 Tiny change: 'asks :D!\n[user:visitWorld,2017-06-25]\nScoring ' -> 'asks :D!\n\nScoring '
en5 English send_nodes 2017-06-25 21:35:08 437
en4 English send_nodes 2017-06-25 20:35:14 254
en3 English send_nodes 2017-06-25 17:41:38 78
en2 English send_nodes 2017-06-24 22:45:07 0 (published)
en1 English send_nodes 2017-06-24 22:44:42 1743 Initial revision (saved to drafts)