### cip999's blog

By cip999, history, 2 years ago,

Hello Codeforces!

Thanks for taking part in the SWERC 2021-2022 mirror. We hope you enjoyed thinking about the problems.

The contest was intended for a wide range of participants. As such, there were "very easy" to "easy" problems (A, M, H) as well as extremely challenging ones (B and J, neither of which appeared in the official contest, together with C). Some problems demanded the knowledge of specific techniques, algorithms or data structures (e.g. E, G, K, J), while others were purely based on insight and deduction (B, D, N).

But without further ado, let's present the editorial!

## Solutions

Solution of Problem A

Statement by dario2994, preparation by dario2994

Solution of Problem B

Statement by Giove, preparation by Giove

Solution of Problem C

Statement by gangsterveggies, preparation by gangsterveggies

Solution of Problem D

Statement by tap_tapii, preparation by tap_tapii

Solution of Problem E

Statement by Petr, preparation by Petr

Solution of Problem F

Statement by Simon, preparation by majk

Solution of Problem G

Statement by cescmentation_folch, preparation by cescmentation_folch

Solution of Problem H

Statement by majk, preparation by majk

Solution of Problem I

Statement by tap_tapii, preparation by gangsterveggies

Solution of Problem J

Statement by Simon, preparation by Simon

Solution of Problem K

Statement by gog.gerard, preparation by gog.gerard

Solution of Problem L

Statement by gog.gerard, preparation by gog.gerard

Solution of Problem M

Statement by cip999, preparation by cip999

Solution of Problem N

Statement by cip999, preparation by Delfad0r

Solution of Problem O

Statement by Simon, preparation by Simon

• +150

By cip999, 3 years ago,

Problems A, B, C, D, E, F are "div 2" problems, while problems G, H, I are meant to be solved by Grandmasters. Overall, our goal was to provide a problemset that could be enjoyable for a wide range of participants and such that the winner could solve all the problems.

There were three big "jumps" in the difficlty gaps between consecutive problems. Problems A and B are meant to be easy, many contestants have the skills and the techniques to attack them (and, maybe, to solve them). Problems C, D, E, F are gradually harder but the difficulty gap between C and F is not as large as usual (and this is reflected in the score distribution). The same holds for problem G, H, I; the difficulty gap between G and I is relatively small (but there is a big score difference because coding I is much harder). Sadly, we discovered 14 minutes into the round that problem I has already appeared in a contest (most likely also in Polish contest, if you know it please tell us in the comments). See also this comment.

Pre-contest predictions

Detailed overview on the problemset and a bit of behind-the-scenes

Which author did what?

Some thoughts from cip999

## Hints and solutions

A

B

C

D

E

F

G

H

I

If you find any typo, feel free to tell us with a comment. Moreover, if you want to share your opinion on the problemset, we are eager to read it.

• +533