lperovskaya's blog

Three Subregionals Cup 2015: Western QF
By lperovskaya, history, 9 years ago, translation, In English

We gladly invite you to participate in the Three Subregionals Cup 2015 – a team-based online programming competition parallel to the ACM ICPC Subregionals in Moscow, Minsk and St. Petersburg. The tournament will be organized by the team of Yandex.Contest and the jury of the Subregionals. The online rounds will be held on the Yandex.Contest system. The dates and start times of subregionals are: Moscow – October 18, 12:00 MSK, Saint Petersburg – October 24, 13:00 MSK, Minsk – November 04, 18:00 MSK.

Teams that participate in the onsite version of one of the three quarterfinals will be able to participate in the online versions of the other quarterfinals via Yandex.Contest. Teams that don’t participate in any of the three quarterfinals onsite will be able to participate in all of them online via Yandex.Contest. Cumulated results of three subregional contests will be calculated based on Grand Prix 30 scoring system.

You can register for the online rounds at any time. You can represent a single person or create a team using the teams link. Each invited team member has to confirm his participation in the team. You can choose participation type and team members upon registering for the contest.

The rules of the online rounds correspond to the onsite quarterfinal's rules.

For your convenience a test contest is available.

UPD: MoscowQF registration is now open. Don't forget to accept team invitations to participate as a team

UPD2: Please, do not look at MoscowQF Results, if you want to solve the mirror-contest ;)

UPD3: Registration for Northern QF is now open. Welcome!

UPD4: Registration for Western QF is now open.

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9 years ago, # |
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I was trying to register as a team but in the process I registered individually. How can I now register as a team ? Is it possible to cancel my participation as it is possible in Codeforces ?

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    9 years ago, # ^ |
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    Same problem.

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    9 years ago, # ^ |
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    send a feedback message with that request, we'll cancel your individual registration promptly

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9 years ago, # |
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Yandex competing with Codeforces for "Most Delayed Contest Platform" award.

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9 years ago, # |
← Rev. 4   Vote: I like it +25 Vote: I do not like it

Hi, when will the final result of Moscow QF be available?

Edit: It is available now :) thanks

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9 years ago, # |
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How to solve H?

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    9 years ago, # ^ |
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    Если предположить, что удалять выгодно не более 256 элементов, то динамика

    ЗЫ Как это доказать??

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      9 years ago, # ^ |
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      У нас неравенство для константы чуть больше пятисот. мы легко можем взять >=(1+2+...+n-256*n). И используя n — k мы возьмем <= (1+2+...+n-k+256*(n-k)). Если первое больше второго, то такое k нам не подходит. n+(n-1)+...+(n-k+1)>256*(2*n-k).Понятно, что для k примерно равного 256*2 неравенство сойдется. Победа!

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        9 years ago, # ^ |
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        я, если честно, ничего не понял(

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          9 years ago, # ^ |
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          Попробую еще раз. Если ты взял k чисел, то i-е из них -- (i ^ coef_i), где coef_i < 256. Так как xor с числом, меньшим 256, не меняет ничего, кроме последних 8 бит, то появляется неравенство: |i — (i xor coef_i)|<256. Комбинируя дважды эти неравенства с разными знаками, мы получим то, что я написал выше.

          Глубинный смысл в том, что |(10^5 xor a) — 10^5| очень мало по сравнению с 10^5 (для любого маленького a).

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9 years ago, # |
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How to solve B?

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9 years ago, # |
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Anyone else got WA 15 in problem L of Moscow QF (and know how to fix it)? I've been banging my head for so long now and still have no idea what I did wrong :(

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9 years ago, # |
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how to solve B-Banana Brain's Bracelet? I use kmp both forward(continuous) and backward (split in half),but get wa.

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9 years ago, # |
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how to solve C-Colder-Hotter? I use bineary-search,first x then y,I test many examples,but still get wa.

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    9 years ago, # ^ |
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    My guess is that your solution fails at some point to determine which half should be looked into. It happens when the answer is closer to the middle of the section you're currlently looking at than to left or right section's middle:

    L------------l---------*--M------------r------------R

    Here, if you test whether you should go to left or right it appears that you're moving away from the answer (which is definitely the case). To correctly determine which way to go, ask what happens if you move from l to r (or vice versa), which is the same as asking which of two "new" middles is closer to the answer.

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      9 years ago, # ^ |
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      You can ask what happens when you move from x to x+1. If you receive 0, ans <= x. Else, ans > x.

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9 years ago, # |
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Does somebody try B?I get wa on test 60.If anyone has the same experience,please share your ideas with us?

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9 years ago, # |
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Northern QF Mirror registration is now open!

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    9 years ago, # ^ |
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    А как надо зарегистрироваться, чтобы были учтены результаты с онсайта?

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9 years ago, # |
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Western contest is available for virtual participating. Sorry for late reminder.

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