Nickolas's blog

By Nickolas, 8 years ago, translation,

The contest is over; I hope you've enjoyed it :-) Editorial is here. See you next year!

The third April Fools Day Contest will take place on Tuesday April 1st. This is a joke competition in which solving the problem is often easier than figuring out what the actual task is. Thanks to kit1980, Skiminok, Gerald and MikeMirzayanov for their help in preparing problems.

In this round you'll be given several weird problems (the estimated quantity is between 6 and 10) 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 — well, unless the problem says otherwise :-)

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

• +370

 » 8 years ago, # |   0 Sounds very interesting! I will play my fool part!2333 Enjoy the contest!
•  » » 8 years ago, # ^ |   +10 Best contest ever... Thanks Nickolas
 » 8 years ago, # |   0 April Fools Day Contest is a fantastic contest~!!!! I believe all of coder can enjoy such an amazing contest!
•  » » 8 years ago, # ^ |   0 Do you think so, now?
•  » » 8 years ago, # ^ |   0 You are right!!!Very ~ interesting~!!!
 » 8 years ago, # |   +11 Seems there will be more problems than last year. More probleams means more fun!
 » 8 years ago, # |   0 this will be my first april fools contest, hope not too weird
 » 8 years ago, # |   +82 I think it will be rated,because it's April fool's day~:)
•  » » 8 years ago, # ^ |   0 that's right. I think too.~
•  » » 8 years ago, # ^ |   0 Haha, maybe we are too suspicious of it. :p
•  » » 8 years ago, # ^ |   -26 I think that it should be unrated.
•  » » » 8 years ago, # ^ |   0 Death_Knight_DK is only joking.
 » 8 years ago, # |   +3 Sounds great!Hope not be a fool!QvQ And note "Be warned, to enjoy competing in this round you'll need a sense of humor compatible with mine!".I think it will be a happy day and rated:)
•  » » 8 years ago, # ^ |   0 Take a look at last years contest http://codeforces.com/contest/290 You will definitely participate after that :)
 » 8 years ago, # |   +2 I love April Fools Day Contest! Can't wait to try. :)
 » 8 years ago, # |   +8 April Fool's Day surprise: contest will be rated :D
 » 8 years ago, # |   -19 Do you want to see how accepted solution becomes wrong answer? Just visit the blog and enjoy! http://codeforces.com/blog/entry/11335 Everyone should keep it in mind who uses "w+"/"r+" in c++ for file handling. Do not be more fool!!
 » 8 years ago, # | ← Rev. 2 →   -8 Don't ignore it! You will regret :)
 » 8 years ago, # |   -8 Any statement will lose its reliability once it's about April Fool :)
•  » » 8 years ago, # ^ |   +8 ^this too, so, this is correct @_@
 » 8 years ago, # |   0 not sure if there actually will be a contest or it's just another April fool.
•  » » 8 years ago, # ^ |   0 I think there will be a contest. You can find 2013's and 2012's
 » 8 years ago, # |   0 Maybe there's no contest at all and that's just the trick haha :D
 » 8 years ago, # |   -8 April Fools surprise: Every task is impossible and everyone ties. :)
 » 8 years ago, # | ← Rev. 2 →   -8 Are they fooling on the countdown page too?
•  » » 8 years ago, # ^ |   +17 Are you referring to registration ending after contest start? If a contest uses ACM ICPC rules (no hacks), there is no need to assign participants to rooms, so the latecomers don't have a problem registering after the contest start. In the past years we used to extend registration till the end of the contest per particilants requests, and this year we've decided to do it beforehand. P.S. Funny how neither approach is a safeguard against questions about registration duration :-)
 » 8 years ago, # | ← Rev. 2 →   -32
 » 8 years ago, # |   +5
 » 8 years ago, # |   -6 On the one hand, I hope the describtion of the problems is not very difficult for foreigners. On the other hand, the harder to understand the meaning of the problems, the more interesting the contest is.
 » 8 years ago, # |   -7 Why it wouldn't be rated? I think there will be much participants if the contest is rated.
 » 8 years ago, # |   0 No joke in Google homepage? Disappointed. But here is All of Google Jokes for April Fools' Day 2014. :)
•  » » 8 years ago, # ^ |   0 you can catch pokemons on google maps :D
 » 8 years ago, # |   +6 Before the end of the registration 02:02:22 Before the contest 00:02:22:D
 » 8 years ago, # |   0 no way to understand the problems exactly ><
•  » » 8 years ago, # ^ |   0 = =
 » 8 years ago, # |   +5 Stone, scissors, paper
•  » » 8 years ago, # ^ |   0 I have to tilt my head to realize that "8<" is scissors. .__.
 » 8 years ago, # |   +2 It was realy hard to understand ! No idea how A+B may not be A+B .
•  » » 8 years ago, # ^ |   +1 you had to try send it many times
•  » » 8 years ago, # ^ |   +5 It was A + B
•  » » 8 years ago, # ^ |   +2 You just need to keep pushing :)
•  » » 8 years ago, # ^ |   +2 just give up
•  » » 8 years ago, # ^ |   0 Problem setters make mistakes in input data for samples! LOL
•  » » » 8 years ago, # ^ |   0 I just pushed writeln(a+b) and wrong answer at 1 test .
•  » » » » 8 years ago, # ^ | ← Rev. 2 →   0 if a = 5 then 19else if a = 381 then 873else a + bOr I am just lucky when I submit this version!
•  » » » » » 8 years ago, # ^ | ← Rev. 2 →   -8 My accept was converting int to string.  int a, b; cin >> a >> b; stringstream s; s << a + b; cout << s.str(); 
•  » » 8 years ago, # ^ |   -9 it is simply A+B, but u just have to shorten ur code a lot to get AC! :D here is my solution 6212422 (after 5 WAs :P)
•  » » » 8 years ago, # ^ |   +1 That wasnt the crack.The thing was, keep submitting . After 5WA, it will get Accepted!So true to the contest problem :)
•  » » » » 8 years ago, # ^ |   -8 lol, the first WA told me shorten the code. can't believe i actually did that 5 times!! :D
•  » » » 8 years ago, # ^ |   0 Actually, it's not related to the code length. You only need to get 5 WAs first and then the AC will come. It's really an April Fools' gift :)
•  » » 8 years ago, # ^ | ← Rev. 2 →   +28 F..ck, I sent it 5 times and then gave up! On 6-th they were giving ACs! =(
•  » » » 8 years ago, # ^ |   -17 What's AC and WA ?
•  » » 8 years ago, # ^ | ← Rev. 2 →   -11 The trick was to not print a newline after printing out the sum. In Python, incorrect: print(a+b) Correct: sys.stdout.write(a+b) Edit: After noticing the "5WA" thing, I realised that this is probably not correct. ^_^
•  » » » 8 years ago, # ^ |   0 Nope, it was not the trick. See above, you just had to keep submitting the same code.
•  » » » » 8 years ago, # ^ |   0 Haha, just noticed... This is a very funny problem. x)
•  » » » » 8 years ago, # ^ |   -8 or, like me, believe the checker saying to shorten code and keep submitting different codes which produce same output A+B! :D
•  » » » » » 8 years ago, # ^ |   +4 The checker simply said "Looks really wrong to me.", not "Looks really long to me."
•  » » » » » » 8 years ago, # ^ |   +8 thanks, i misread that during contest! but i guess that was good in a way, because i wouldn't have tried to reduce code length and resubmit! :D
 » 8 years ago, # |   +3 Fortran, but which one?
•  » » 8 years ago, # ^ |   0 FORTRAN 77
•  » » » 8 years ago, # ^ |   +1 Did you print it without a default leading space character or not?
•  » » » » 8 years ago, # ^ |   0 I’ve sent the following, based on an example from Wikipedia:  603 FORMAT("FORTRAN 77") 90 WRITE(6,603) STOP END 
•  » » » » » 8 years ago, # ^ |   0 I sent the following (WA):  program hello print *, "FORTRAN 95" end program hello and this one (AC):  program hello print *, "FORTRAN 77" end program hello To be honest, I am not sure which one is correct ;)
•  » » » » 8 years ago, # ^ |   0 I did
•  » » » 8 years ago, # ^ |   +45 Why the hell is it FORTRAN 77 while the compiler was gfortran95?
•  » » » » 8 years ago, # ^ |   +9 The same question from my side.
•  » » 8 years ago, # ^ |   +1 77
•  » » 8 years ago, # ^ |   0 Yes, I also got this question here is my first submit — 6206074 and next a lot of submits just checked version for version :(
 » 8 years ago, # |   0 What the hell was C?
•  » » 8 years ago, # ^ |   0 min(a[0],a[1],a[2]//2,a[3]//7,a[4]//4)
•  » » » 8 years ago, # ^ |   0 Fine, but how did everyone guess?
•  » » » » 8 years ago, # ^ |   +1 You weren't given N, so one could guess that there are always 5 numbers. Then you're given a recipe with 5 items, so it was quite reasonable to try how many full products can you make given the quantities.
•  » » » » » 8 years ago, # ^ | ← Rev. 2 →   0 I thought you couldn't infer that since the following works without specifying the N. But, i should have tried anyway. :(int main() { int temp; while(cin >> temp){ cout << temp << endl; } }
•  » » » » » » 8 years ago, # ^ |   0 Usually doesn't happen with numbers on Codeforces — you're given N as well. Someone can correct me if I'm wrong though.
•  » » » » » » » 8 years ago, # ^ |   0 oh ok..sorry i don't have a lot of experience with codeforces so that was my assumption.
•  » » » » 8 years ago, # ^ |   +1 google translate or insight :D
•  » » » » 8 years ago, # ^ |   +1 Try google translate :)It looks like a recipe, so I guessed that we will need 1 of the first element, 1 of the second element, 2 of the third element, 7 of the fourth element, and 4 of the last element to create one item.Which implies we can create min(a[0],a[1],a[2]/2,a[3]/7,a[4]/4) item.
•  » » » » 8 years ago, # ^ |   +1 Put the letter into Google Translator and you'll find it is written by Italian. And the key-point five numbers show up...
•  » » » » » 8 years ago, # ^ | ← Rev. 2 →   +3 -
•  » » » » 8 years ago, # ^ |   +1 Copy & paste the code to google translate and then you can guess :) The rough idea is that every substance is formed by 5 elements, blablabla..
•  » » » » » 8 years ago, # ^ |   0 Whoa :)I understood the recipe, but the “how many full items” part was obscure to me anyway.
 » 8 years ago, # |   +6 I think that someone told people how to solve F around end. (Anyway, nice contest!)
•  » » 8 years ago, # ^ | ← Rev. 2 →   +61 It's OEIS A000001. Couldn't tell why but this is the greatest (joke problem) idea I've ever seen :P(After RUINING counting problems again and again, OEIS finally helped creating a great one LOL)
•  » » » 8 years ago, # ^ |   0 no wonder the problem name was 000001! :D i thought it had something to do with binary representation! :D
•  » » » 8 years ago, # ^ |   0 How did you realise it?
•  » » » » 8 years ago, # ^ |   +3 By OEISing the sequence in people's code after contest.I have only failed submissions during contest. Wondering how people realize it too :-
•  » » » » » 8 years ago, # ^ |   +29 In desperation, I did a search with wildcards on OEIS looking for any sequences that matches the samples and noticed A000001 there by chance after trying few others.
•  » » 8 years ago, # ^ |   +3 I was sure this task is something about binary representation...
•  » » » 8 years ago, # ^ |   0 Maybe, it was contrived intentionally.
 » 8 years ago, # |   0 First 1.5 hours : 2 AC Last 0.5 hours : 3 AC :O
 » 8 years ago, # |   +25 Best contest ever
 » 8 years ago, # | ← Rev. 2 →   +2
 » 8 years ago, # |   +20 Thank you very much for yet another fun contest!
 » 8 years ago, # |   +45 G: Excel helped a lot :) http://imgur.com/iGdsj2A
•  » » 8 years ago, # ^ |   +5 I can't parse this word, can you explain me please?
•  » » » 8 years ago, # ^ |   +4 5 + AVG Y. Basically average the y-coordinates, and add 5.
•  » » » 8 years ago, # ^ |   0 it's something (3 or 5 or S) +AVGY
•  » » » 8 years ago, # ^ |   0 It's "5 + A V G Y" which means that you just need to print out 5 plus the average value of y[] lol..I saw those graph during contest but cannot come up with that ideaQAQ
 » 8 years ago, # |   0 Loved it!!Dont wanna wait another year for it :(Great Work :)
 » 8 years ago, # |   0 Contest was really funny enjoyed it :-)
 » 8 years ago, # |   0 Best april fools day I have ever had) thx a lot
 » 8 years ago, # |   +8 We need April's Fool every month! It was very challenging and interesting :)
•  » » 8 years ago, # ^ | ← Rev. 2 →   0 yea
 » 8 years ago, # |   0 I had so much fun! =D
 » 8 years ago, # | ← Rev. 2 →   0 In I-task I really thought that i need evaluate left part to zero and at the same time satisfy conditions from the right part. I was writing this task all contest time and finally i've just submit solution which only checks conditions and recovers minimal possible values. Surprisingly i've got AC :)
•  » » 8 years ago, # ^ |   0 I guess you mean I. In that case, the third sample case breaks that hypothesis. (I also had the same thought until I evaluated the third sample case.)
•  » » 8 years ago, # ^ |   0 why is the answer 0101 in the last sample?
•  » » » 8 years ago, # ^ |   0 (x) means x parentheses.You need (3) to be greater than (2). Of course, you put (2) = 0 and (3) = 1. Now read the jaw: it spells (2), (3), (2), and (3) in order. So you feed the golorp with 0101.
 » 8 years ago, # |   +6 6225906 cant believe i was so close, but yet so far to solving B! :D
 » 8 years ago, # |   0 What is the mystery of problem F?
•  » » 8 years ago, # ^ |   +1
 » 8 years ago, # |   +8 i became an April fool today.
 » 8 years ago, # |   +8 u know the contest was unusual when u see that Petr made 11 wrong submissions on one problem and 22 wrong submissions on another (before, ofcourse, solving both in the end)! :D
 » 8 years ago, # |   0 Among all 27 people that solved 7 problems, they all miss two of F, G, I. Clearly these are the most difficult problems (D follows). Any one of them could have nabbed the first place by thinking more creative...Amazing contest. I'm going to keep OEIS open in a tab for next year's contest. F successfully fooled me into thinking "floor of log2(x) — 1" and "floor of square root of x", especially after I figured out test 5 (1: 1) and test 6 (3: 1).
 » 8 years ago, # |   +12 For F: 000001 -> OEIS A000001 ... Seriously guys ? =)))))))))))
 » 8 years ago, # |   0 I'm still wondering in D. Should I submit for every combination of 16 bytes?
•  » » 8 years ago, # ^ |   0 No. Input N, output "1" if fact #N is true, "0" otherwise
 » 8 years ago, # |   +11 Didn't get the solve for problem H A+B in the contest time.. :D I submit my solution five times and give up... i wish i would try only once more.. i would get Ac... :) Nice problem though.. We have a lot of fun..... :)
•  » » 8 years ago, # ^ |   0 6 times = Accepted :(
 » 8 years ago, # |   +5 Again, I got the email announcing this contest 3 hours before the contest (at 5:30 AM in my time zone). Please next time send this email earlier.
 » 8 years ago, # |   -7 so, when will the ratings be updated? P.S. oops :D
 » 8 years ago, # |   0 is E straight forward math or is there a twist to it?
•  » » 8 years ago, # ^ | ← Rev. 2 →   0 I found the page where the image came from but could not relate the values (e.g. 1.2, 3, 2). Just occurred to me that I did not even come close to exhausting the meaning of, for example, (1.2, 3, 2).[EDIT] Forgot the link: http://mathworld.wolfram.com/SquarePyramid.html [/EDIT]This contest is fun — it comes close to IPSC.
 » 8 years ago, # |   0 For the last problem, is the idea to choose values for the left side and make it minimal so that the right condition holds? I see there are several parts in the right side separated by comma which seems strange to me..is this a programming language specific thing?
•  » » 8 years ago, # ^ |   +3 Please see the editorial: http://codeforces.ru/blog/entry/11391?locale=enBasically, golorp's name is a Prolog expression ("golorp" is "prolog" spelled backwards).