Nickolas's blog

By Nickolas, 4 weeks ago, translation, In English,

The contest is over; I hope at least some of you enjoyed it :-) The editorial is published here.


The 7th April Fools Day Contest will take place on Monday April 1st. This is a joke competition in which solving the problem is often easier than figuring out what the actual task is.

In this round you'll be given several weird problems and 2 hours to solve them. The contest will use ACM ICPC rules (no hacks, the standings are decided by the number of solved problems and penalty time earned on them), and it will be unrated. You can submit solutions in any language allowed by Codeforces. To get an idea of what the contest will look like, you can check out the contests of the past years: 2012, 2013, 2014, 2016, 2017, 2018.

As usual, to enjoy competing in this round you'll need a sense of humor compatible with mine. Good luck, and have fun!

 
 
 
 
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4 weeks ago, # |
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surprisingly tough ....XD

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4 weeks ago, # |
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It's humor and Accepted that create fun.

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The best contest of the year :D (not that I perform well in it)

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    3 weeks ago, # ^ |
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    I take back my comment.

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      3 weeks ago, # ^ |
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      before contest: so excited !!! after contest: whatever :)))))

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        3 weeks ago, # ^ |
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        Trying to solve those yes/no problems gets boring quickly when every hypothesis you make turns out to be wrong.

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4 weeks ago, # |
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ravioli ravioli, what is in my 1st april contestoly?

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4 weeks ago, # |
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I have been waiting for this contest

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4 weeks ago, # |
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Will this year have April Fool's contests on other platforms? Last year there were other 2 big ones at least, but I couldn't find any this time.

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4 weeks ago, # |
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Is it rated?

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4 weeks ago, # |
Rev. 2   Vote: I like it -8 Vote: I do not like it

.

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3 weeks ago, # |
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Unrated:Let's solve the problems just for fun!I hope everybody have fun.XD

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3 weeks ago, # |
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No problem statements plz

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    3 weeks ago, # ^ |
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    I am tempted to follow this request, since for one of the problems writing the statement (in two languages) took strictly longer than writing all other pieces of the problem, and it certainly will be the case for another problem... But alas, I aim for variety of jokes above all, so some of the problems have to have a statement :-)

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3 weeks ago, # |
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After contest is over : Your rating has been decreased.

Happy april fool's day. LOL.

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3 weeks ago, # |
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"When the contest begins" Surprise! There is no contest :)

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3 weeks ago, # |
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Nobody:

Me:

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3 weeks ago, # |
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A classified source just confirmed that this round will be rated :P :P :P

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3 weeks ago, # |
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It's April Fools, so during the contest suddenly it will become rated =)

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3 weeks ago, # |
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Why unrated? :(

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3 weeks ago, # |
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it's unrated, i hope so.. XD

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3 weeks ago, # |
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It's April 1st, the contest may suddenly starts 2 hour earlier XD

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3 weeks ago, # |
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2012,2013,2014-2016,2017,2018 Mathematically, u shouldnt be doing an april-fools contest this year o.O

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3 weeks ago, # |
Rev. 2   Vote: I like it +36 Vote: I do not like it

I hope, in this year, this will not happen with me ...

Capture
image uploading site

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    3 weeks ago, # ^ |
    Rev. 2   Vote: I like it +8 Vote: I do not like it

    It was normal that you got wrong answer. You had to make a program that makes 2 good bets in roulette. The results were made randomly (like in normal roulette). The best strategy was to bet on red or black (even or odd), because you have 48.6% that your bet will be good. That means 23.6% chance to pass main tests (only 2 test cases). While the results were random, the Answer section were made by the code of author that got accepted, so that can't be always good. In your case the result was 10 (black), so you got WA.

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    3 weeks ago, # ^ |
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    so, can I ask what is the contest id of the problem?

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3 weeks ago, # |
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To all the other teams which are attending ICPC WF, let's join this contest together!

Spoiler
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3 weeks ago, # |
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Exciting!

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3 weeks ago, # |
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This is my first April Fool's Day contest. exciting!!!

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3 weeks ago, # |
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Fools Day happy~~ : )

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3 weeks ago, # |
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This contest won't get rated afterwards, right?

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    3 weeks ago, # ^ |
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    No one knows. It is April's fools contest, anything can happen :D

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3 weeks ago, # |
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I hope I won't become a fool after this contest :3

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3 weeks ago, # |
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The 7th April Fools Day Contest will take place on Monday April 1st.

Nickolas It's 32nd march, fix it.

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Is it rated??

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3 weeks ago, # |
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fool time .?

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3 weeks ago, # |
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real fun

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chutiyaap

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Rev. 5   Vote: I like it 0 Vote: I do not like it

(https://drive.google.com/open?id=1BEDXr5N2ZR5Hf5Q4jHsbAxPjX69aO-Pu)

Spoiler
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Goodluck and have fun everybody!

2xh1p7

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3 weeks ago, # |
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It is should be April fools night contest for me :3

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3 weeks ago, # |
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The image in the Russian version of 1145C - Mystery Circuit is broken for some reason, here is what it should be:

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    3 weeks ago, # ^ |
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    Should've supported Q# submission, missed opportunity. Tssk tssk.

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It's the first time I get rank1.

I'm so happy.

XD

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3 weeks ago, # |
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Wonder how the editorial will look like...

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3 weeks ago, # |
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D has great speiling

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3 weeks ago, # |
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Due to the unethical and ugly behavior of some members of the community, this round will be rated. Let's solve problems just for fun!

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3 weeks ago, # |
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Please post the editorial as soon as possible. Eagerly waiting (to submit :P).

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3 weeks ago, # |
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How are so many people solving D can anyone post the answer :D :P

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3 weeks ago, # |
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Toughest Constest ever
Can't even go through the problem statements.

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3 weeks ago, # |
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I have seen some previous years April Fools Contest problems but this is the lamest April Fools Contest of all time. No offence

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3 weeks ago, # |
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Tutorial for problem B please :)

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I made a bet with my senior ray-asuka that if I could not become a candidate master before my birthday(4.2), I would invite him and my teammates to dinner. This round was my last chance, and he got his wish.

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3 weeks ago, # |
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Paper

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3 weeks ago, # |
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Felling like a real fool :(

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3 weeks ago, # |
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two plus xor of third and min element?

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    3 weeks ago, # ^ |
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    YES!

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    3 weeks ago, # ^ |
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    how did you even come up with that solution?

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    3 weeks ago, # ^ |
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    How did people guess this on the first attempt, with only one sample case?

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      3 weeks ago, # ^ |
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      It's the wrong letters, they make up sentence.

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      3 weeks ago, # ^ |
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      exactly !! how ??
      Xor seems intuitive... but what about min^3rd + 2 ...
      Its impossible without extra hints

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      3 weeks ago, # ^ |
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      Note that there are typos in the statement. Write down all the letters that should be replaced by some other letter for the correct spelling. This is the message you get.

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3 weeks ago, # |
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My solution for E: if $$$i$$$ gives remainder 1, 4 or 5 mod 6, then yes. Sadly, it's a wrong solution, but it perfectly fits.

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3 weeks ago, # |
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((min(id,25)+id)%(2+id%3))>0

I found it after 1min of the contest...

THAT'S AWESOME!

UPD: Problem E

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    3 weeks ago, # ^ |
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    And where did this magical condition come from?

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      3 weeks ago, # ^ |
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      It comes from the Fourier transformation of the image 1 to 20. (my poor English :D

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    3 weeks ago, # ^ |
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    $$$\{[\min(\mathrm{id},25)+\mathrm{id}]\bmod(2+\mathrm{id}\bmod3)\}>0$$$

    That's neat!

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3 weeks ago, # |
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Editorials please!

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3 weeks ago, # |
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Well, I managed to brute force B after 50 attempts...

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    3 weeks ago, # ^ |
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    i do the same for problem C :)

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      3 weeks ago, # ^ |
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      I made the same for both :P

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      3 weeks ago, # ^ |
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      How do you bruteforce C when you need to guess a number? Seems like it would take a lot more attempts :o

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        3 weeks ago, # ^ |
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        Tests turned out to be ordered by numbers in their input)

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        3 weeks ago, # ^ |
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        I made it with supposing that the answer is also between 0 and 15. I wasn't sure on it, but I tried it. Later I noticed that each number has different answer.

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        3 weeks ago, # ^ |
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        Input has 4 bit. Circuit looks like some kind of bit shuffling / adding. So we can guess that output is in range [0, 15] and has some kind of pattern.

        --> basically just submit some educated guess. You can look at my submissions to see how I guessed it.

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    3 weeks ago, # ^ |
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    curious about how to brute force on YES/NO problems

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      3 weeks ago, # ^ |
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      Make sure it answers correctly for first 4 tests. Then try to get 5th test with binary search — answer no to everything (else), then yes to 50..99, etc. Eventually I realized the test cases are in increasing order which made things a lot easier — just need to find the next value to "flip" the answer on.

      That's pointless on any serious contest because the number of attempts it takes will give you around 0 points.

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3 weeks ago, # |
  Vote: I like it +110 Vote: I do not like it

You: TWOPLUSXOROFTHIRDANDMINELEMENT

Me, an intellectual: LTABRACCANEPGZEFBOHPNOSIFASOMC

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    3 weeks ago, # ^ |
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    An intelleqtual

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    3 weeks ago, # ^ |
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    I knew this fact quickly because i use google translator... kk

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    3 weeks ago, # ^ |
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    And wtf is that "mine element" :|? Got this message pretty quickly but had no idea what to do with it.

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      3 weeks ago, # ^ |
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      Notice how there is only 1 e, not 2 e(minelement isn't mineelement).

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      3 weeks ago, # ^ |
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      I guess it is "min" element. btw which message are you talking about?

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        3 weeks ago, # ^ |
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        By message I meant hidden statement "two plus (...)"

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      3 weeks ago, # ^ |
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      fece is a correct word, so MIN element ...

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        ... but it took me half an hour to figure it out :D Also had MINE there at first ...

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    3 weeks ago, # ^ |
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    SBEVE

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1% of time to read statements, 99% of time to guess and attempt, lol

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    3 weeks ago, # ^ |
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    You missed 1% (I wrote it before he edited his comment).

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    3 weeks ago, # ^ |
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    The 1% was wasted... ;-D

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      3 weeks ago, # ^ |
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      Seems some guys did not agree with my humor and downvoted for it. :(

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        11 days ago, # ^ |
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        I also got massively downvoted for some other comment on that day. Seems some didn't appreciate that contest to the point of being in really bad mood...

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3 weeks ago, # |
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Why can't I view others' solutions? System Checks?

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Only one task... Ahahahah, the best contest)) I want more!

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3 weeks ago, # |
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my wrong solution for C: A circle with cross indicates 4(because of cross); A dot indicates 1(because it's a dot); Note that the input number is between 0 and 15, so make it become binaries. for the example: 3->0011->the last line(4+1+1+1) + the third line(4+1+1) =13;

I think this is reasonable but got WA , sad...

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    3 weeks ago, # ^ |
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    It's actually just some quantum logic gates of 4 bits.

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    3 weeks ago, # ^ |
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    Yes, you are right, but you need to turn the number(n) given to us, and only then calculate according to the scheme. After, reverse result and transfer to the decimal numeral system. Read this article: https://en.wikipedia.org/wiki/Toffoli_gate

    В общем почитайте статью https://en.wikipedia.org/wiki/Toffoli_gate (есть на русском). Надо тип перевести n в 2-ую систему счисления, перевернуть число, посчитать по схеме, потом перевернуть результат и перевести в 1-ую систему

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3 weeks ago, # |
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Use the most foolish way to spend April Fools' Day lol!!!

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Rev. 2   Vote: I like it +35 Vote: I do not like it

I am so happy to be the second person to solve problem C!!

All because I listened carefully in the [Quantum Computing] class when COIWC2019(Chinese Olympiad in Informatics — Winter Camp)!!

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3 weeks ago, # |
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Why the problem B wants to ban KAN? Just a joke

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in D i used grammarly to get the grammatically correct sentence to make it readable. rip

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3 weeks ago, # |
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Solution of A:N/4

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    3 weeks ago, # ^ |
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    really? i brute forced the whole solution :P

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    3 weeks ago, # ^ |
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    In the first test case n was 4 but the answer was 4 not 1

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3 weeks ago, # |
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For B:There Is a "YES" in Her "NO".

iywim

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Now I regret because I voted that I love this contest before it starts..

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3 weeks ago, # |
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Please help in problem A.

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    3 weeks ago, # ^ |
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    In each step, delete either the right half of the matrix or the left In order to get a part of the numbers ascending sorted Print the longest length of a sorted array you can obtain

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3 weeks ago, # |
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Problem A is straightforward — no sense of humor required to solve it.

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3 weeks ago, # |
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Will the links to contestant solutions be available?

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    3 weeks ago, # ^ |
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    You should be able to see the solutions now.

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3 weeks ago, # |
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congrats to applese for winning the 2019 fools contest!

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3 weeks ago, # |
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I truly believe that it is so funny to run the competition.

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3 weeks ago, # |
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We are used to look for the editorial in the end of the post, not in the beginning.