Привет, Codeforces!
Мы рады объявить об очередном раунде на csacademy.com. Раунд #15 пройдёт в среду, 30.11.16 в 19:00 (Мск). Если вы хотите принять участие в этом раунде, Вы должны зарегестрироваться перед началом. Контест будет проведён как обычно, для Div1 + Div2, с 7 заданиями разной сложности, которые надо решить за 2 часа и 30 минут.
Мы рады представить вам авторов этого сета: josdas и bluemmb.
А так же огромное спасибо Yury_Bandarchuk за перевод заданий на русский язык.
Формат конкурса:
- Вам предлагается решить 5 задач за 2 часа.
- Мы обеспечиваем обратную связь на протяжении всего конкурса.
- Задачи не будут засчитываться частично: то есть либо вы выполнили задание, либо нет (ACM-ICPC-style);
- Оценки будут присваиваться в динамике: в зависимости от количества пользователей, которые справились с проблемой, оценка будет варьироваться от 100 до 1000;
- Помимо баллов, у каждого участника будет "пенальти", который будет учитываться при определении победителя.
О системе пенальти:
- Пенальти вычисляется по следующей формуле: время, потраченное на выполнение последнего выполненного задания + "пенальти" за каждую решённую задачу. "Пенальти" для каждой решенной задачи равен log2 (no_of_submissions) * 5.
- Решения, которые не компилируются или не подходят для примеров тестовых случаев игнорируются.
- После того, как вы решили задачу и отослали результат, вы можете поэкспериментировать с решением, все последующие ответы уже не будут учитываться.
Изменения платформы с раунда #14
Новый форум
С правой стороны в шапке сайта, сразу за секцией с блогом, вы можете найти ссылку на наш форум:
... это выглядит примерно вот так:
Форум создан как single page app (Приложение одной страницы), то есть Вам не надо постоянно обновлять страницу чтобы увидеть изменения, они отображаются автоматически в реальном времени.
Geometry tool
Вы можете найти этот инструмент в секции приложений, сразу под редактором графов (Graph Editor):
Добавлены новые языки
Во время контеста мы рекомендуем работать с языками C++ и Java.
Как всегда, мы советуем использовать обновлённую версию Google Chrome. Если вы обнаружите какие-либо ошибки, пожалуйста напишите нам по адресу contact@csacademy.com или в комментариях.
Wrong Date mentioned.
Fixed, thanks.
Perl :D
Do you have any special compilation commands that you'll want?
We have 0 to no experience with perl :)
The geometry tool is very useful, thanks.
but I think it still need some improvements.
Yeah, it's still kinda buggy, but we decided to launch it anyway :P.
In conclusion, we should expect a lot of geometry problems this round, I suppose.
Something is very wrong, site is down? Can't log in or submit problems :(
same here!
At least we can solve problems :)
same here! too
I cant log in either, and the site is very slow, pls fix it.
Not able to login. Says "Invalid Token"
Same case
Cant login through linked fb account too.
Why I cannot login?
Seems like introducing new features in the platform, didn't go well with the old ones!
Have tried even with Google accaunt, didn't work..
I cannot login too. I am using firefox.
the bug not fixed yet :(
can't login
Can we get any feedback about this?
It's been fixed now.
I was able to make a submission and now I am logged out and same errors again!
Submitting does not work for me.
Site is again down :(
Nothing happens when I click sign in... THis is after everyone is saying it is fixed?
Seems like it's OK now.
Can't submit! The button doesn't respond on clicking.
UPD: Oh, seems like it's been pushing my submissions in the queue without telling me...
We are sorry for the inconvenience, everything should be ok now. We are not sure if the contest will be rated or not, but it will be prolonged by at least 15 minutes.
Can't submit :/
Try refreshing the page, it should work now.
Still not working?
It's working now. If you have any problems refresh the page, please.
about, csacademy, are all the tests applied to a submission, or it's like codeforces with pretests and final testing?
We don't have pretests, so if your solution passes then it's accepted.
I still cant submit (I refreshed the page, and close the browser), the site says that I'm not connected to the servers.
Try refreshing the page, it should work now.
The site is down for me. Neither i'm able to compile or submit :(
Try refreshing.
Guys, come one.. I have tried to submit C problem for 20 mins..
It says, too many submissions, but I when I check them, only 4 of them are made(which I made about 40 mins ago)
Workspace is nice for show-off, but not useful if it does not show meticulously in cases of high load if my code is getting submitted or not. Same code getting submitted multiple times due to site instability and not getting to know if it is getting submitted it or not until I check out my submissions 2-3 minutes later.
A simple file upload alternative mechanism should be in-place to submit code.
+1, I don't know how I took +8 on third problem
Did you accidentally press Ctrl+u? This hotkey submits the code.
Occam's razor: repeatedly clicking Submit is more likely than accidentally pressing a combination of keys located far from each other and from any other commonly used combination.
Yes, this is exactly what happens. After pressing submit, half of time nothing shows up(like it is submitting or running or not) — so it is highly likely that one will press Submit again.
Same, I was just lucky that my first submission got accepted :)
Is it rated?
Nope
In problem "Substring Restrictions", I use two pointer to get k such that s[i] = s[i + k] or s[i] = s[i — k]. I just choose minimum and maximum k and join(i, i + k) / join(i, i — k). Surprising, it passes. Is test case weak?
At the same time my right solution got TL12, until I ran bruteforce in case of small len in query.
If this is your solution, I can't understand why it passes the following testcase:
Can someone discuss the approach for Base K Xor https://csacademy.com/contest/round-15/#task/base-k-xor/ ?
Where can I find editorials, if available?
https://csacademy.com/blog/#round-15
I solved K based Xor using digit dp though it was not totally mainstream.
Nice problems :)
Can you share your code ?
I did that too (: