### ABalobanov's blog

By ABalobanov, history, 6 months ago,

I came up with the problem and could think of only $O(Prt(n) * poly(n) * log(n))$ solution ($Prt(n)$ -- number of non-decreasing partitions of number $n$). Given $n$, find a permutation with maximum possible value of $\sum_{i = 1}^n \sum_{j = i}^n max(p_i, p_{i + 1}, ..., p_j)$. My solution works in $n <= 50$ (maybe more with precalc). Is it possible to solve it better?

• +11

By ABalobanov, history, 8 months ago,

Hi everyone! There is another bunch of problems I used in some programming school and want to share so here is Krosh Kaliningrad Contest 2 in gyms which starts 04.12.2021 14:00 (Московское время). Everyone is welcome. I suppose problem difficulty level is from cyan to orange though there will be harder problems. Duration of contest is 3 hours.

Upd: reminder: contest starts in 2 hours. Upd: contest starts in 8 minutes. Good luck!

Thanks everyone for participation! Congratulation to the winners:

Announcement of Krosh Kaliningrad Contest 2

• +27

By ABalobanov, history, 15 months ago, translation,

Hi everyone! I would like to share a contest from problems I suggested in some programming school. These problems are by my own and some by Mosyagin. Is starts on this Wednesday at 18:00 Moscow time (see your timezone https://www.timeanddate.com/worldclock/fixedtime.html?day=24&month=2&year=2021&hour=18&min=0&sec=0&p1=166). You will be given 8-9 problems. I think they are educational a bit(but may be not all). I would be glad if you will participate and give me some feedback. Don't be too strict anyway it's one of my first such experience though I always wanted to make a contest. You can find contest in gym with name Kaliningrad Krosh Contest 1. It's duration 3 hours, statements will be on Russian and English.

Tutorial of 8 of 10 problems(except E and J): https://drive.google.com/file/d/1i_H_OFlPyx4uAtzD4r6PxRxI2bEXs76V/view?usp=sharing

Announcement of Krosh Kaliningrad Contest 1

• +81

By ABalobanov, history, 6 years ago,

How to count number of bracket sequences with n opening brackets and m closing brackets so that the balance never gets negative? I came to this problem thinking about other one(D from previous Open Cup), and I can't solve it in sufficient complexity. Is there a way to do it with n <= 2000, m <= 2000, answering one query in O(1) time or somehow precomputing these values for all i, j <= 2000?