Codeforces Round #589 (Div. 2) Editorial

Revision en2, by McDic, 2019-09-29 17:58:00

Hello, I hope all of you enjoyed my contest!

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[Behind story of A]

  • There is a successful hack for A. I am really surprised.
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[Behind story of B]

  • There is no behind story.
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[Behind story of C]

  • Initial version of C statement consists of tons of mathematical formula. CF team and testers requested me to reduce amount of mathematical formula.
  • This problem was added before a week to the round. If there was no such C, the balance would be bad.
  • Thanks for dorijanlendvaj , he improved test data for C a lot!
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[Behind story of D]

  • Same as C, I wrote tons of mathematical formula in D. After CF team's request, I reduced the amount of formula.
  • This is my personal favorite problem among ABCDEF.
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[Behind story of E]

  • MikeMirzayanov changed the name of problem before 10~20 minutes to the contest. I feel so sad because he forced this change too lately, but I understand his intentions.
  • This problem was the easiest to prepare data. Just pure random and $$$k=1$$$ is strong enough.
  • I managed to create $$$O(n^3)$$$ pypy3 solution for E in 1 second lol.
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[Behind story of F]

  • This problem was the hardest to prepare data. We considered more than 10 types of trees to block various kind of WA solutions.
  • I intended top-down error-toleration based case handling approach for this contest, but seems other approaches are also ok.

[Behind story of G (removed problem)]

  • Nobody(including red testers) solved this problem for a week. This problem is saved as spare problem for another Div.1 contest.
  • I love this beautiful problem than any other problems I ever made.

Thanks in advance!

Tags mcdic

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en7 English McDic 2019-10-01 02:40:10 467
en6 English McDic 2019-09-29 18:27:42 64
en5 English McDic 2019-09-29 18:18:42 0 (published)
en4 English McDic 2019-09-29 18:02:41 86
en3 English McDic 2019-09-29 17:59:17 75
en2 English McDic 2019-09-29 17:58:00 14
en1 English McDic 2019-09-29 17:55:47 1822 Initial revision (saved to drafts)