Nickolas's blog

April Fools Day Contest 2021
By Nickolas, 4 years ago, In English

The contest is over; I hope you enjoyed it! The editorial is available here.

The 9th April Fools Day Contest will take place on Thursday 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, unless the problem says otherwise. 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, 2019, 2020.

Good luck, and have fun!

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4 years ago, # |
  Vote: I like it +36 Vote: I do not like it

Is it rated?

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4 years ago, # |
  Vote: I like it +5 Vote: I do not like it

'problem is often easier than figuring out what the actual task is' it means it will be fun without any cost/rewards. Hahaha... Interesting

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4 years ago, # |
  Vote: I like it +38 Vote: I do not like it

Editorial can be found here.

https://www.youtube.com/watch?v=dQw4w9WgXcQ

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    4 years ago, # ^ |
      Vote: I like it -27 Vote: I do not like it

    sir it is only a song on youtube, where is the editorial??????

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    4 years ago, # ^ |
      Vote: I like it +44 Vote: I do not like it

    Wow, what an amazingly interesting and detailed editorial! Thanks!

    For problem D, how do you implement the part where it says

    We've known each other for so long

    Your heart's been aching, but you're too shy to say it

    Inside, we both know what's been going on

    We know the game, and we're gonna play it

    I'm having a bit of trouble with my code here, can anyone help?

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      4 years ago, # ^ |
      ← Rev. 4   Vote: I like it +182 Vote: I do not like it

      We've known each other for so long

      • This is a reminder to use 64 bit integers to avoid overflow in intermediate calculations of cross products.

      Your heart's been aching, but you're too shy to say it

      • Since this is a cancerous 3D geometry problem, it causes terrible heartburn for anyone who attempts to spend the 5 hours required doing geometry implementation. The problemsetter is too shy to add the geometry tag to the problem though, because he is afraid of the downvotes on the editorial that will follow.

      Inside, we both know what's been going on

      • Only the points inside the 3D convex shell matter. Both Alice and Bob know to only pick these inner points.

      We know the game, and we're gonna play it

      • This one goes without saying: it's a competitive programming problem, so of course this just winds up being a game of, you guessed it, Nim.
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        4 years ago, # ^ |
        ← Rev. 2   Vote: I like it +26 Vote: I do not like it

        Thanks for this detailed explanation.

        I couldn't solve this by myself. I guess I am just too blind to see this hidden meaning.

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    4 years ago, # ^ |
      Vote: I like it +17 Vote: I do not like it

    not funny, especially when everyone knows XcQ

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    4 years ago, # ^ |
      Vote: I like it +63 Vote: I do not like it

    Sorry but I have memorized the link lol

    maybe you should hide the link under the text

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      4 years ago, # ^ |
        Vote: I like it +5 Vote: I do not like it

      it still will be visible in the lower left corner

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    4 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it

    I'm still waiting for a year when the statement for one of the tasks in April Fools day contest is just this

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4 years ago, # |
← Rev. 2   Vote: I like it +2 Vote: I do not like it

Given I already know one of the problem, Should I become one of the tester? :P

April Fool's Problem

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4 years ago, # |
← Rev. 2   Vote: I like it +85 Vote: I do not like it

1

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4 years ago, # |
  Vote: I like it -15 Vote: I do not like it

If you practice you will become red

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4 years ago, # |
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good luck every body!!1! i hope to reach gren

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4 years ago, # |
  Vote: I like it 0 Vote: I do not like it

it would be fun if there were hacks in the contest

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4 years ago, # |
  Vote: I like it +36 Vote: I do not like it

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    4 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    can you explain this..didnt get it.

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      4 years ago, # ^ |
        Vote: I like it +5 Vote: I do not like it

      Just observe what's written below A, B1, B2, and C.

      7045, 5658 and 3987 are common years while 1964 is a leap year.

      So basically that's the reason why the guy got sad.

      Wasn't that obvious ?

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4 years ago, # |
  Vote: I like it +10 Vote: I do not like it

Finally a rated contest XD

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4 years ago, # |
← Rev. 2   Vote: I like it +44 Vote: I do not like it

Also known as: April Rage Contest :p

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4 years ago, # |
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Good luck to everyone! I hope this "competition" will be cool and funny.)

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4 years ago, # |
← Rev. 2   Vote: I like it -7 Vote: I do not like it

.

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4 years ago, # |
  Vote: I like it +6 Vote: I do not like it

submit more than five times then get the ac.....

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4 years ago, # |
  Vote: I like it +76 Vote: I do not like it

what if at the start of the contest they say APRIL FOOL there is no contest.

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4 years ago, # |
  Vote: I like it 0 Vote: I do not like it

How to be a good coder?? Can you tell me some way to think the solution for a problem? I don't know where to start or what to think first!

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4 years ago, # |
  Vote: I like it -31 Vote: I do not like it

will this contest be helpful for placements

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    4 years ago, # ^ |
      Vote: I like it +6 Vote: I do not like it

    this is the placement -.-

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    4 years ago, # ^ |
      Vote: I like it +9 Vote: I do not like it

    All questions asked in Today's contest will be repeated in placement test.Hurry up!Remember All questions.If u missed even single testcase You will not going to get 1cr.

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4 years ago, # |
  Vote: I like it +161 Vote: I do not like it

The comment is hidden because of too negative feedback, click here to view it

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4 years ago, # |
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How Many Problems will be there and problem ratings?

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4 years ago, # |
  Vote: I like it +6 Vote: I do not like it

not conduct the contest and tell everyone that we fool u guys :)

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4 years ago, # |
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Can we think that the fact this round will be unrated is also April's fools day's joke? :)

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4 years ago, # |
  Vote: I like it +28 Vote: I do not like it

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4 years ago, # |
  Vote: I like it +4 Vote: I do not like it

would you even believe today if I tell you something real?? Brave browser which is an open source web browser is now acquired DuckDuckGo which is a search engine mainly focuses on privacy of user.

Let me know if you think I am making you fool.. because you may be fool if you think I am making you fool. LOL

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4 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Wait is today April 1st? I thought today is March 32nd

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4 years ago, # |
  Vote: I like it +37 Vote: I do not like it

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4 years ago, # |
← Rev. 2   Vote: I like it +3 Vote: I do not like it

What if, it turns out, they were fooling us about the contest' start time and we all got fooled :v

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    4 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it

    What if, it turns out, they were fooling us about the contest being unrated and we all got fooled ¯_(ツ)_/¯

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4 years ago, # |
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deleted

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4 years ago, # |
  Vote: I like it +4 Vote: I do not like it

aprilfool.

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4 years ago, # |
  Vote: I like it +3 Vote: I do not like it

Kinda sad that this blog post be getting more upvotes than 3 educational round announcements combined

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4 years ago, # |
  Vote: I like it +17 Vote: I do not like it

How the hell is tourist first even in this contest XD. I can't even get past the 2nd problem. I even searched if there's a thing such as digital millennium calculation act in desperation.

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4 years ago, # |
  Vote: I like it +4 Vote: I do not like it

Am I April fooled by the server almost not working for me 30 minutes?

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4 years ago, # |
  Vote: I like it +3 Vote: I do not like it

IS IT RATED? IS IT RATED? IS IT RATED?

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4 years ago, # |
  Vote: I like it +80 Vote: I do not like it

lol ‎ ‎ ‎‎ ‎ ‎ ‎ ‎ ‎‎ ‎ ‎ ‎ ‎ ‎‎ ‎ ‎ ‎ ‎ ‎‎ ‎ ‎ ‎

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4 years ago, # |
  Vote: I like it +1 Vote: I do not like it

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4 years ago, # |
  Vote: I like it +4 Vote: I do not like it

This contest made me realize that besides being dumb, I am also a brick.

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4 years ago, # |
  Vote: I like it +4 Vote: I do not like it

No worry, the Standings will be inverted!

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4 years ago, # |
  Vote: I like it +3 Vote: I do not like it

SecondThread solved B after 37 incorrect submissions.

Sounds like me solving a task after reading the editorial.

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    4 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    B example: input: 54817 ans: 7 5 + 4 + 8 + 1 + 7 = 25; 2 + 5 = 7; So the ans is 7 :)

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4 years ago, # |
  Vote: I like it +67 Vote: I do not like it

Me googling about roots (B-DMCA)

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4 years ago, # |
  Vote: I like it +24 Vote: I do not like it

The biggest problem to solve I was to wait for custom invocation to run something :(

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4 years ago, # |
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Can anyone explain D and/or F?

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4 years ago, # |
  Vote: I like it +10 Vote: I do not like it

Nice contest. Too bad the custom invocation for the secret language doesn't return anything most of the time. Was H a program for Z80 processor? I solved it just by looking at hexdump, not sure if that was intended.

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4 years ago, # |
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what is the secret language?

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    4 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    The Seriously programming language (later renamed to Actually; also, it seems that the version on the server is outdated, as several commands didn't work there).

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4 years ago, # |
  Vote: I like it +12 Vote: I do not like it

Seriously, how to get better at doing April Fools Day Contest?

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4 years ago, # |
  Vote: I like it 0 Vote: I do not like it

It is a rare experience to find that you get passed for a problem that the god did not...

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4 years ago, # |
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Could anyone tell me the idea of C?

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    4 years ago, # ^ |
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    s[i] — 'A' == (s[i — 1] — 'A' + s[i — 2] — 'A') % 26

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    4 years ago, # ^ |
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    HINT: sum of ASCII value of previous two characters

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    4 years ago, # ^ |
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    Check s[i] == (s[i — 1] + s[i — 2]) % 26 for every i >= 2. Don't forget to subtract 65 from every letter. (65 is 'A' in ASCII) Code

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    4 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    you have to take alphabets as number i.e. A=1,B=2,...

    As written Fibonacci suggests that the previous two char's addition should give the current char

    if string follows such pattern then YES else NO ( if length of string<=2 then print YES )

    if any two characters addition exceeds 26 i.e. U+V=20+21=41 then take modulo with 26 i.e. (U+V)%26=15

    My solution : 111691458

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4 years ago, # |
  Vote: I like it 0 Vote: I do not like it

ToOoOoOo000 Hard!!!

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4 years ago, # |
  Vote: I like it +3 Vote: I do not like it

BrainFuck Contest

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    4 years ago, # ^ |
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    For F, I was googling "How to write brainfuck in brainfuck ? "

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      4 years ago, # ^ |
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      Lol, I actually tried submitting brainfuck in english, because it was giving some different answer on custom innovation with Secret Programming Language

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4 years ago, # |
  Vote: I like it +1 Vote: I do not like it

Can someone tell me how they decoded the braille in F? I spent an hour but couldn't find any good online converter.

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4 years ago, # |
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How to solve B?

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4 years ago, # |
  Vote: I like it +3 Vote: I do not like it

BrailleForces

(1505G - Encoded message is about Braille too)

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4 years ago, # |
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why answer in B is (x — 1) % 9 + 1?

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4 years ago, # |
  Vote: I like it +14 Vote: I do not like it

Fancy contest! But that feeling when i see editorial of problem D,

but you know how it is when you're trying to remember a fancy-sounding word and come up with all kinds of similar-looking ones?

Spoiler
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4 years ago, # |
← Rev. 2   Vote: I like it +34 Vote: I do not like it

Problem I : Unlike the past years, this time any code you submit in ``Secret 2021'' language will run successfully — or at least produce no recognizable error.

Meanwhile submiting fuck you gives RTE and tells you the name of the language.

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