### rsFalse's blog

By rsFalse, history, 10 months ago, ,

Lets discuss problems.

How to solve A Alice and path, F Fizz and Bazz, J Cubic path?

• +24

By rsFalse, history, 11 months ago, ,

Good morning. Does anyone knows if the 2nd division of GP of Europe will be held today? It's 40 minutes after the contest should have started.
11.11.2018 12:00 Grand Prix of Europe

Upd. div. 2 system appeared and is planning to start at 13:00

• +39

By rsFalse, history, 23 months ago, ,

Слабовато работает поиск, вводил слово 'opencup' — ничего не нашли ( https://i.imgur.com/QJlbes7.png ), хочу поискать через '→ Прямой эфир', там всего пара десяток тем, а утонувшие нету как откапать либо я незнаю. 'Детальнее →' к сожелению списка тем неразширяет.

• +3

By rsFalse, history, 2 years ago, ,

I suggest an idea of table with shortened info about contest, where it is written:

[date][starting time][duration][divisions and if they are combined][is it rated][number of problems][scoring system]

Because otherwise some need to ctrl+f and read sentences to understand what does "Div.1 + Div.2" mean, and trying to find what duration of contest is.

• -10

By rsFalse, history, 2 years ago, ,

Which problems did you enjoy the most? I enjoyed problem N.Kitchen (div.2), a very interesting math problem. How to solve div.2. G and O?
P.S. I have found that upsolving of 15, 16, 17 rounds have appeared!

• 0

By rsFalse, history, 3 years ago, ,

Problem B was very interesting, but haven't overcome tc #7.

• +47

By rsFalse, history, 3 years ago, ,

Hello,
I had a problem: make sequence of random permutations which elements do not occur in same positions. E.g. I have list ('a', 'b', 'c', 'd'). I randomly generate permutation, say 'a d b c', then next permutation, say 'd c a b, then next permutation can not start with 'a' and 'd', because these elements occurs in first or second sequence on same position.
My algorithm is slow: I repeat to generate random (with Fisher-Yates shuffle) permutation and check each element if it not occur in previous sequences (I used 2D array). How to determine what is the complexity of my algorithm?
How to solve problem faster?

• 0

By rsFalse, history, 3 years ago, ,

"16. 24.04.2016 11:00 Grand Prix of South Caucasus" 11:20 and contest still not opened :(

• 0

By rsFalse, history, 4 years ago, ,

Again, participating in contest and having "Service is not available". This time — an hour after contest started.

• 0

By rsFalse, 5 years ago, ,

Hi, folks. Some days ago something happened: since then I can't see submissions, see anybody's rating graphs, can't write comments, vote, can't write private messages. Isn't that only for me? I can't write pm to admin :/ , and didn't find any other contact [upd: I wrote to email, have thought about it later]. Sorry, if there are more folks with that problem and simply you can't respond.

• +19

By rsFalse, 5 years ago, ,

I've participate in Div.2 contest and enjoyed many of the problems. Let start discussions about problems?

How did you solve N, O?

Upsolving is ON.

Next: 12. 29.03.2015 11:00 Grand Prix of America

• +24

By rsFalse, 5 years ago, ,

I've found here the shedule of Opencup contests: http://www.opencup.ru/index.cgi?data=ocf/schedule&menu=index&head=index (Nearest round — at this sunday)

• +15

By rsFalse, 5 years ago, ,

Hi, I'm interested in downloading all my submissions. Today I wanted to find: how often I used some functions or keywords in my all accepted submissions, what is the time when I used some first, and other information. It would be easier to do, if I have all submissions in my PC, because then I could easily 'grep' such info. And if someone downloads his submissions, he could store them in his own database, and add his own marks.

• +3

By rsFalse, 5 years ago, ,

Opencup.ru: "3. 16.11.2014 11:00 Grand Prix of Central Europe" — contest had to start more than 1 hour ago, but still no information about it. Notification: "The contest is temporarily not available. Please, retry the request a bit later". Such poor.

• 0

By rsFalse, 5 years ago, ,

Every day, when I press "c" and "Enter" at my browser, it loads me codeforces.com. But I want text to be russian. So I need to change locale — press on Russia flag. Previously it was working for longer time, but now it doesn't work for longer time, and I need to press Russia flag again and again. Why it is so? Can't it be remembered? I understood that I should change domain from COM to RU to avoid this problem, but it is not convenient.

• 0

By rsFalse, 5 years ago, ,
• When someone successfully hack another participant, his/her test join set of final tests.

Sometimes it can be useful and fair, because sometimes set of final tests is not covering some cases where at least one participant made a mistake.

For example: At #260 Div.2 A there were incorrect submission — 7385198, which passed all system tests, but it could not pass elementary test

3
1 2
2 3
3 1


so if someone successfully hacks using this test, this test should go to set of final tests.

Of course then the number of final tests can grow up to number of all participants, and this would slow down testing.

• +89

By rsFalse, 5 years ago, ,

Используете ли вы генерацию тестов? как часто? на каком языке пишете? поделитесь примером.

• 0

By rsFalse, 6 years ago, ,

Жаль, что совподает время проведения соревнований. Ранее помню в воскресения бывало по вечерам.

• +9

By rsFalse, 6 years ago, ,

Неужели трудно включить регистрацию за 24 ч. до соревнования Codeforces? в чем заключаеться беда?

Что делать потенциальным участникам, которым время соревнований являеться несколько неудобным, и они с удовольствием присоеденились-бы к ним, во время или чуть позже их старта, но имеют проблему регистрации — просто напросто немогут быть за компом во время дня и зарегистрироваться, так как регистрация начинаеться ночью а не раньше — напр. вечером?

Напр. в выходные уезжаешь на деревню до воскресения вечера, и если вернулся раньше чем закончилось соревнование и есть немало времени, то еще хочеться принять участие, но проблема в том, что незарегистрирован. То же самое с буднями. Я бывает только вечером оказываюсь за компом (у меня обычно начало в 17:30). Вообще у меня такой случай, когда время регистрации удобней не за 10/16 ч. до старта, а тупо в диапазоне -24 до -20 часов до старта.

• -19

By rsFalse, 6 years ago, ,

Youtube. Задача B (Div.2) — решал 15 мин., но правельно нерешил. Это третий мой скринкаст. Извените, паузы невырезаны..

• -7

By rsFalse, 6 years ago, ,

Youtube. Второй мой скринкаст. Задача A (Div.2). 12 мин на решение. Извените, паузы размышлений вырезать пока неумею..

• +5

By rsFalse, 6 years ago, ,

Было лень почитать с начала. Так начал с того места, где написаны буквы с неравенствами... http://codeforces.com/contest/376/problem/D . Невчитался. Так что начал решать другую задачу — просто найти наибольшую подматрицу из едениц. Наверника, вышло, только в time-limit непоместиться... http://codeforces.com/contest/376/submission/5513912 Интересно, которая из задач — сложнее. С возможностью переставлять строки или без. Пойду попробую решить с возможностью.

• -37

By rsFalse, 6 years ago, ,

Ненашел, где ошибаюсь.

• 0

By rsFalse, 7 years ago, ,

• -3

By rsFalse, 7 years ago, ,

219A - k-Строка

3064232

So strings in FPC can have up to 255 chars, i think. But test case can contain: 1 ≤ |s| ≤ 1000 .

If test case is: "2 aaaa" Answer is: "aaaa"

If test case is: "2 a{x 254}" Answer is: "a{x 254}" — http://ideone.com/h7t6hg

If test case is: "2 a{x 256}" Answer by my program is: "-1" — http://ideone.com/S9ZefD But I think expected was "a{x 256}"