Codeforces Round #431 Editorial

Revision en14, by cyand1317, 2017-09-03 11:58:39

Hi, dear contestants!

With the end of Codeforces Round #431 (Div. 1 and Div. 2), some might be complaining behind the screen that problems are too tricky or hard, or have been struggling with some supposedly solvable problem... Yes, this time problems seem hard, but anyways, I hope they provided you with something, say rating, fun, ideas, or experience. I don't want to see anyone losing confidence because of failure (bad luck) in a single contest — please, don't do so.

Here are the hints, tutorials and codes for the problems. Feel free to discuss about problems in the comments, and point out if something is incorrect or unclear. Thank you!

849A - Odds and Ends

by cyand1317

Hint
Tutorial
Model solution

849B - Tell Your World

by cyand1317

Hint
Tutorial
Tommyr7's solution (first idea)
Model solution (second idea)

848A - From Y to Y

by cyand1317

Hint
Tutorial
Kalinin's solution
Model solution with knapsack (!)

848B - Rooter's Song

by cyand1317

Hint
Tutorial
Model solution

848C - Goodbye Souvenir

by adedalic

Hint
Tutorial
Model solution

848D - Shake It!

by cyand1317

Hint
Tutorial
Model solution

848E - Days of Floral Colours

by cyand1317

Hint
Tutorial
O(n^2) solution
Model solution

Behind the scene and random things (read if tired of problemsolving)

Expand

Thank you for reading. Next round? Perhaps something more traditional, who knows? Believe me, I'll try harder if this happens.

Cheers! \(^ ^)/


UPD Packages for problems are uploaded. They are in Polygon format and contain everything including statements, tests & generators, validators & checkers, and solutions. You can download them from Google Drive or Baidu Drive.

Tags 431, editorial

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en14 English cyand1317 2017-09-03 11:58:39 360 Packages
en13 English cyand1317 2017-09-02 20:31:52 2 Tiny change: ' of $O(n^{1/3})$.\n</' -> ' of $O(n^{2/3})$.\n</'
en12 English cyand1317 2017-09-02 12:39:53 3048 Random
en11 English cyand1317 2017-09-02 11:19:11 469
en10 English cyand1317 2017-09-02 10:46:08 1817 Add tutorial for D1E
en9 English cyand1317 2017-09-02 08:01:50 381 Add tutorial for D1D
en8 English KAN 2017-09-01 23:06:51 30
en7 English cyand1317 2017-09-01 21:16:58 70
en6 English cyand1317 2017-09-01 21:13:07 151
en5 English cyand1317 2017-09-01 21:08:32 37
en4 English cyand1317 2017-09-01 20:57:17 149 Add the fourth tutorial
en3 English cyand1317 2017-09-01 20:30:43 423 Add first three tutorials
en2 English cyand1317 2017-09-01 19:30:26 138
en1 English cyand1317 2017-09-01 19:07:49 20161 Initial revision (published)