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Контест окончен, надеюсь, вам понравилось :-) Разбор задач — здесь.

В воскресенье 1 апреля состоится шестой Первоапрельский контест — несерьезное соревнование, в котором решить задачу зачастую проще, чем догадаться, что же в ней надо сделать.

Впрочем, в этом году я постаралась сделать задачи менее загадочными и более разнообразными. Так, например, почти во всех задачах есть условие! А вот OEIS вам не понадобится :-)

В этом раунде вас ждет 7 необычных задач, на решение которых дается два часа. Раунд будет проводиться по схеме ACM ICPC (без взломов, положение в результатах определяется количеством решенных задач и набранным штрафным временем) и будет нерейтинговым. Решения можно сдавать на любом языке, поддерживаемом Codeforces. Чтобы получить представление о том, что вас ждет, можно взглянуть на контесты прошлых лет: 2012, 2013, 2014, 2016, 2017.

Как обычно, чувство юмора, совместимое с моим, является необходимым условием для успешного участия. Удачи!

Комментарии (119)

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shubhiks1032

7 лет назад, # |

+83

Last time I had one problem solved; with OEIS problem gone, I wonder about my results now :v

→ Ответить

sdssudhu

-69

I think one of the things this year will be that the contest will start an hour before or after (It will be a nice one).

OnlyVim

_S1MPLE_

+128

Xellos

-176

plasticBottle?

ez_zh

7 лет назад, # ^ |

← Rev. 3 →

-43

No.

I_LOVE_METSUKA

-38

Lol now you are going to get upvotes. Not because it was creative, because you are red coder.

And you're wrong. How unsurprising.

(I wrote that fully expecting to get downvoted, just to make the forced joke.)

They are downvoting you because of me. People do opposite to what I say. Guys can you upvote this comment? :)

Sharon

+184

A red getting downvotes? April fools came early this year.

-30

Why don't you delete his comment Mike? You already deleted my comment. Is it because he is red?

+16

I'm sure you deleted your own comment.

-33

You can't delete a comment 5 minutes after it is written mr.smart.

KKpoker

really doubt i can solve any without OEIS lul

athin

+12

As you may probably know, there will be another similar April Fools Contest run by Indonesian coders: TOKI Open Contest Special — April Fools 2018 which will end 1 hour before Codeforces' contest start!

You may use this as an exercise tho, ;)

Gassa

+36

Additionally, there is a CodeFights Fools' Day Marathon which starts 25 minutes after the Codeforces special round and lasts for 90 minutes. So, one can solve April Fools' problems all day! Or night, depending on where on the globe you are at the moment.

_Md_AL_AMIN_

+18

I am Exited to be the fool by seeing the statement :D :D :D

Ahmed-

"And you won't need OEIS this time."

April fool maybe! xD

CODEFORCESHASROTTEN

-20

"solving the problem is often easier than figuring out what the actual task is"

Codeforces Round #471 Problem B anyone?

dorijanlendvaj

+44

I don't understand how did people not understand that problem... I think most people just didn't read the sentence "Check whether it can be split into two non-empty subsequences such that the strings formed by these subsequences are adorable.", or the sentence "Let's call a string adorable if its letters can be realigned in such a way that they form two consequent groups of equal symbols (note that different groups must contain different symbols)."

sankalp_

-16

Well... What if there is not gonna be a contest because April fools :P

farmersrice

minimario

Magolor

← Rev. 2 →

-18

The 6th April Fools Day Contest will take place on Sunday April 1st.

No, April 1st is Saturday. :)

UPD: at least I didn't say "Monday" ...

nantf

I suddenly hate this time......I live in China,and that's at almost midnight.Also I will have to be in school!

Bill_Yang

← Rev. 4 →

-31

The contest doesn't exist! Happy April fools' day!

GNAQ

almost all problems have a statement??????That's Terribleeeee!

physics0523

Is this UnRated isn't it?

By the way,in Japan,the contest will be held in April 2nd(00:35) lol

UPD:I didn't notice that a RedCoder ask the same question because it gets so many downvotes lol

312352145215

+17

Thank you Nickolas, for your contests, there are really interesting and unpredictable :D

Assaduzzaman_Sohan

You should increase contest duration.

Max_Hasan

Last year this contest made me mad... WTH, only input and output?... are you kidding me =)

+25

Something will be strange in China...

the contest starts at 23:35 UTC+8, it means after half an hour, it's April 2nd.

Does it mean we should stop joking? Will we be able to see the original problem statement with out jokes?

Seems worse in Japan...

(Joking)

NreK

+10

Can't wait for this contest, super hyped for the funny questions!

MonsterInMe

i took this statement for granted at the first sight,"This is a joke competition in which solving the problem is often easier than figuring out what the actual task is." ,but when i went through previous contests,i could feel it ..XD!!

at the first sight i took this line for granted "This is a joke competition in which solving the problem is often easier than figuring out what the actual task is."but after going through previous contests ,i could really feel it..XD

Deathly_Hallows

the problem about April Fools Contest that we can't believe anything you say

you say we won't need OEIS this time this can mean that all the problems can be solved using OEIS

so it's complicated

Lo_R_D

Если будет задача с необычным чекером, стоит ли рассчитывать на то, что информация получаемая от чекера будет на нескольких языках (рус, англ)? В прошлом году в задаче с котенком у меня была проблема с тем, чтобы понять что от меня хочет чекер.

Kirito.LVL99

Та неее, врятли)

Слишком много хочешь)

Pi_Tigrannik

Nickolas, у вас белая спина...

Akid

Problems only have input and output?!!! i think that will be hard.

racsosabe

The joke this year is that the servers will go down during the contest.

Wait, isn't every contest an April Fools Day contest? Lol

FLEA

+14

nice round

sometimes unrated contests are also necessary ,we can think freely :D

tushar_1997

-12

Unrated or rated ? Beware you could become a Fool XD

jounary

A is very simple!enjoy it!

right from which you have evolved and left which helps you evolving ...

nikolay_zakharevich

+65

...

solvemproblr

I think, Problem D can be solved using DP+LCA+Ternary-Search :)

Febrin

-63

longhuenchan

You know you somehow leaked out the solution lol

Nickolas

+82

Please don't give solution hints while the contest is still running. If this happens we'll have to make it unrated. Oh wait...

hell_hacker

According to the rating predictor I am gaining rating. Please don't make it unrated :P

IIIIIIIIIIIIIIIIIIIII

I think, according to solvemproblr's predictor he wasn't gaining rating, so he decided to make contest unrated. ;)

iMurat

Единственный контест, где я имею представление что делать

mohab1211

me in the contest XD

Linkus

How to solve D?

I printed the word "black" and it passed.

Ralsei

I passed with "2nd 12" (and didn't with "black" or "even") I guess, right answer changed time to time.

enoone

I have printed "2" two times one time it gave me WA2 another time WA1. So the test cases were random.

Norrius

I bet on even.

It was random.

I actually tested from 0, 00 to 36 looking for the answer.

But it was to answer any of these "odd", "even". XD

quality

Printed 1st 12.

Pish4

Try betting "Even" until random accepts it :D

I printed 19 to 36

1 to 18 failed

From the above comments I think that the system spins the roulette when you submit an answer.

starboy_jb

-37

Let me hack D plz xD

shahincsejnu

I`m Unlucky :( are you lucky :P help me to become lucky :D :D

tdkd

Can anyone help me in Problem D, I don't know how to do, but I found test 1 change from 3,10,13,36.

cai_lw

Just bet anything you like. If you win the bet, you get accepted. So just keep submitting something like print('Odd') until you win.

F — 3 sample:

'-' = 45, '1' = 49, '2' = 50 ect. (ASCI)

112 = ( 49 * 10 + 49 ) * 10 + 50 = 5440

-37 = ( 45 * 10 + 51 ) * 10 + 55 = 5065

5440 - 5065 = 375

But how to decide the rest I did not understand...

waterfalls

+15

The author of the reference solution, while decoding ascii strings to numbers, accidentally added the plus/minus characters to the next number. Note that to determine the value of a digit, you subtract '0' (=48) from it.

2+2 = ('2'-'0') + ('+'-'0')*10 + ('2'-'0') = 2 + (-5)*10 + 2 = -46

The rest follow similarly.

.tx

112 = (('1' - '0') * 10 + '1' - '0') * 10 + '2' - '0' = 112

-37 = (('-' - '0') * 10 + '3' - '0') * 10 + '7' - '0' = -263

112 - -263 = 375

Well, okay...)

anuragkanodia

How to solve Problem D ?

HDevillez

You just have to print "black" or "even" and be lucky

Soul_Full_Of_Thunder

I printed "Odd" and get AC

How to solve E ?

Count hard and soft. Chessboard alternates color black, white. Find smallest size square chessboard such that we may place all hard in one color, and soft in the other.

jonathanpaulson

You are supposed to print out the size of the smallest square chess board that could fit the cheeses if you put hard cheeses on one color of squares and soft cheeses on the other color.

-___-

I had this idea but decided to count the number of 'm' in input instead

How to solve B?

Mama_Bullki

Once you're certain what type of cat you're dealing with, output "normal" or "grumpy" to standard out.
You have to print the answer as soon as possible

I always did 6 checks (from 0 to 5)

WolfBlue

You can sometimes do it in one, eg if you see 'no way' then it must be a grumpy cat

check on if "no way", "go die in a hole", "are you serious?", "worse", "terrible".

the number of checks is not more than 6

Just follow the problem description. It's clear enough and you don't need to guess anything.

:/ ummm I think not, considering that the point of the contest is to give problem statements that you have to guess at

soon

How to solve H?

qiancy981

It's quite easy. To get an AC, you don't need to print anything!

Sam

+29

Lol??

You are not alone. I've submitted it for at least 40 times, and at last I failed.

gryphon

SAME HERE ... :( ... # WASTE OF TIME

https://en.wikipedia.org/wiki/Roulette

Bro, I did this searching stuff but I thought that we have to print an Integer.

but actually i print "red" and try several times

ifsmirnov

Why there was no 'Runtime Error' verdict in problem B? I used asserts but it resulted in WA. I spent ~40 minutes to figure it out.

And how exactly did the input in this problem look? I used asserts to check that the given string is one of the strings from the statement, but it didn't pass so I had to remove them to accept the problem.

In B, you must output the type of cat as soon as you figure out what type of cat it is.

I know, but it doesn't answer the question why the code

int main() {
    assert(false);
}

gets WA and not RE.

Hmm, that's interesting... does codeforces ignore asserts, maybe?

Hey man, it's not my first contest on Codeforces :) They work in other problems. Maybe it is specific behaviour for interactive problems, though I haven't ever seen such thing before.

percywtc

Maybe this is also a part of the April Fool... :P

Laggy

lightcode

shadowfax

In B, I was getting WA checking only given words. Then added "normal" and "grumpy" in the list. Guess what? LOL :p

TankEngineer

For problem B, I just tried random and it works magic http://mirror.codeforces.com/contest/952/submission/36819128.

You can't fool me it's not random.

593119681

Oh... Although guessing statements is indeed interesting, I prefer problems with complete statements such as B,C and G. Cost a lot of time guessing statements of E and F but didn't solve any one. ╮(╯-╰)╭