### Nickolas's blog

By Nickolas, 8 years ago, translation,

The contest editorial is available here.

Some jokes are fun only for the first time, repeating them makes them lose their charm. I certainly hope that April Fools Day Contest is not the case, but there's only one way to verify this :-) I'm happy to invite you to take part in the verification process which will take place on Monday April 1st. Let me disprove the suspicions some people have: the joke is the contest contents, not the fact of its existence or the lack of it — that would have been too simple :-)

In this round you'll face several weird problems and 2 hours to solve them. The contest will be unrated (you bet!), and it will follow ACM ICPC rules (no hacks, the standings are decided by the number of solved problems and penalty time earned on them). You can submit solutions in any language allowed by Codeforces. To get an idea of what awaits you, you can have a look at the last year's contest.

Be warned, to enjoy participation in this round you'll need a sense of humor compatible with mine! It's April Fools Day, after all. Good luck!

Upd. Registration is open till the end of the contest.

• +406

 » 8 years ago, # |   +34 I love this kind of contests. Eagerly waiting for it ;)
 » 8 years ago, # | ← Rev. 2 →   -59 Funniest April fool contest would be to have no contest at all :P EDIT: Instead of funniest , I should have written Scariest.
•  » » 8 years ago, # ^ |   +26 Let me disprove the suspicions some people have: the joke is the contest contents, not the fact of its existence or the lack of it — that would have been too simple :-)
 » 8 years ago, # |   -10 If this type of contest held more, then people like it more because it is very interesting. But as @Alizera I am also egurly waiting for it.
 » 8 years ago, # |   +5 At what time will it start?
•  » » 8 years ago, # ^ |   +10
 » 8 years ago, # |   +35 “The contest will be unrated (you bet!)”Isn't it a trick?I wonder...
•  » » 8 years ago, # ^ |   +1 I think it is not. (last year's this contest was unrated.)
•  » » » 8 years ago, # ^ |   +11 Maybe this year they've decided to play trick on us this way
•  » » » » 8 years ago, # ^ |   -11 I don't think so,because the rules of contest is different from CF rounds, it's ACM rules.
•  » » » » » 8 years ago, # ^ | ← Rev. 2 →   +9 There are some contests which were held with using ACM's rules, which are rated contests.For example, this. http://codeforces.com/contest/240
•  » » » » » 8 years ago, # ^ |   +5 You are so careful...But I think they'll have ways to rate it if they really want...All in all,what I said is also a trick.Happy April Fools Day!
•  » » 8 years ago, # ^ | ← Rev. 2 →   +7 i think it isn't a trick because this is different from other contest
 » 8 years ago, # |   +5 Last Year there were no pretests , every solutions that were submitted got accepted ... felling fooled again remembering the funny day a year back ... God knows what surprize is waiting today :)
•  » » 8 years ago, # ^ |   0 Not only God knows that today's contest will follow ACM ICPC rules; therefore — there'll be no pretests :)
 » 8 years ago, # |   +8 Thank you very much for preparing these matches like special-language & April fools ! Great game I can't love it more! Hope you can preparing more for us. Geeks ! Let's have fun , and good luck!
 » 8 years ago, # |   +12 yeah, i will go RED today :D :)
•  » » 8 years ago, # ^ |   0 Wish you will be a grey today! You know i don't mean it. If this is rated wish you will be successful. If this is not then hope you will be red soon :D
•  » » » 8 years ago, # ^ |   +2 Yeah, grey is quite good for april fool :) :p
 » 8 years ago, # |   -34 i hate April fool....
•  » » 8 years ago, # ^ |   -44 ıf(printf("I hate April fool"))dislike();ıf(printf("I love April fool"))like()
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8 years ago, # ^ |
-16

# I love April fool

•  » » » » 8 years ago, # ^ |   -17 I think your program got Wrong Answer :))
•  » » » » » 8 years ago, # ^ | ← Rev. 5 →   -6 I agree with youbecause 20 dislike
•  » » » » » » 8 years ago, # ^ |   -20
•  » » » » » » 8 years ago, # ^ |   0 Are you pro? why you talking so much?
•  » » » » » » » 8 years ago, # ^ |   -8 We are living in Democratically world.
 » 8 years ago, # |   +30 I very expect the weird problems! :D
 » 8 years ago, # |   +26 This will be my birthday celebration contest :D Not to be fooled. 1st April is really my birthday :D I'm eagerly waiting for this contest.
•  » » 8 years ago, # ^ |   +11 So.. wish you a bad birthday? Aha, you know what I mean. Let's enjoy the contest anyway.
•  » » » 8 years ago, # ^ |   +15 And I won't give you thanks bro. I've already given it.
•  » » 8 years ago, # ^ |   +1 Wish u many happy returns of this day in codeforces :)
 » 8 years ago, # |   +14 An only disappointing thing is this contest will be held on April 2 in Japan...(a matter of timezone)
 » 8 years ago, # |   0 It should be very interesting as I think. Good luck!
»
8 years ago, # |
-23

# last ten minute

 » 8 years ago, # | ← Rev. 2 →   +3 Last year's problem A:The input contains two integers a1, a2 (0 ≤ ai ≤ 109), separated by a single space.It's nice.
 » 8 years ago, # |   -13 cannot access the competition for the past 40 minutes. There is some issue. Moderators please look into it.
»
8 years ago, # |
Rev. 4   +5

This is how Google makes people April Fools :

Edit : Those who still think it is real are downvoting ?! :D
 » 8 years ago, # |   0 I am unable to register after the start of the contest :(
 » 8 years ago, # |   +11 it is harder than last year . i didnt solve a problem ! :( . i guess today is just not my day !
 » 8 years ago, # |   +4 It make me crazy,but it is very fun!On the other hand,I think I should learning more American history:)
 » 8 years ago, # |   -20 So, I gues, HQ — (amount of(H) * 11 + amount of(Q) * string.length) % 2 == 0(Yes) else (No)?
•  » » 8 years ago, # ^ |   0 the reasoning: Hello World — 11 symbols Q — amount of symbols in insert string We check if sum of symbols in output devisable by 2Just my gues :D
•  » » 8 years ago, # ^ |   -10 I think, it's equal to amount of(H) % 2 == (amount of(Q) * string.length) % 2 ? "Yes" : "No"
•  » » 8 years ago, # ^ |   +14 From what I found, answer actually depends on order of letters, not just number of them, as for test 4 (HHQQHHQQHH) answer is "Yes", but for test 7 (HHQHQQQHHH) answer is "No".
•  » » 8 years ago, # ^ | ← Rev. 2 →   +23 Can you all please not post your guesses (which everyone did by themselves in a large amount) and post actual solutions if you have AC or any useful observations? Please?
 » 8 years ago, # |   +26 Thanks God It Was unrated :P :D
 » 8 years ago, # |   +14 I'm dying to know what was the idea behind the HQ9+ problem !
•  » » 8 years ago, # ^ | ← Rev. 2 →   -8 I think: H-prints H. Q-prints reversed source code. question: do we have a valid output of some code?
 » 8 years ago, # |   +30 I never really liked raccoons...
 » 8 years ago, # |   0 Fantastic and super fun contest! :)
 » 8 years ago, # |   +24 We want F's sulotion, please.:D
 » 8 years ago, # |   +3 That was very cool and fantastic contest!!! I hope we have much more contests like this!! Thnx Problemsetter!
 » 8 years ago, # |   +59 When I got WA 40 on F and got 1 hour left, I thought I got it... Then one hour trying with so much pain T_T
•  » » 8 years ago, # ^ |   +18 There are 45 tests in this problem.
•  » » 8 years ago, # ^ |   0 I try to run a algorithm to get Hamiltonian Circle and got on WA 40 too..
•  » » » 8 years ago, # ^ |   0 How did you solve it in the contest?I wrote DP, but I got WA on test 4.
 » 8 years ago, # |   0 nightmare....TAT...
 » 8 years ago, # | ← Rev. 3 →   +1 only 1 participant solve problem F :O WTF
 » 8 years ago, # | ← Rev. 3 →   +9 Really amazing contest! AWESOME ! Never competed in such type of contests before.What is the solution for A ( I couldn't figure it out and I cannot wait for the Solve Page ) ?At B I copied the QR image and converted it into a matrix of 0s and 1s. But i tend to think that the solution was (x xor y) % 2 or ((x-1) xor (y-1)) % 2 .Problems C and D were already solved. (in the statement)I have no idea for E and F, but surely HQ9+ is a joke.Great Job! Awesome Contest!
•  » » 8 years ago, # ^ |   0 google the string of 2nd test case
•  » » » 8 years ago, # ^ |   +1 :)) Nice. I think I will become a detective and not a programmer.
•  » » 8 years ago, # ^ |   +7 In problem A you should output the Last Name of the n-th presidenth of USA.In problem B you should read the QR-code and get the link ( http://tc-alchemy.progopedia.com/qr-code.txt ).
•  » » » 8 years ago, # ^ |   -6 That's exactly how i did B :))
•  » » 8 years ago, # ^ |   0 In A you should output the ath president of the US)
•  » » 8 years ago, # ^ |   0 for A: Last name of US Presidents http://www.whitehouse.gov/about/presidents/martinvanburenas a non-US it was tough for me to figure out, but Mr. Van Buren saved me :p
 » 8 years ago, # |   -11 When rating updates?
•  » » 8 years ago, # ^ | ← Rev. 2 →   +38 After the next contest ends xD
•  » » 8 years ago, # ^ |   +8 This is an unrated contest
 » 8 years ago, # | ← Rev. 2 →   +7 I'm curious that how to get all the 40 names for problem A just within 2 or 3 minutes.For problem B, did you generate the 0-1 array with the help of some tool?
•  » » 8 years ago, # ^ |   0 You can search them in Google.
•  » » » 8 years ago, # ^ | ← Rev. 2 →   0 Of course, but after googling, the first page contains some formatted list of names, such as the following: George Washington, 1789-1797 John Adams, 1797-1801 Thomas Jefferson, 1801-1809 James Madison, 1809-1817 ...Then some text processing work has to be done which cost minutes.It seems that Wikipedia doesn't have a clear name-ONLY list either.
•  » » » » 8 years ago, # ^ |   -10
•  » » » » 8 years ago, # ^ | ← Rev. 2 →   +1 import re a = ''' [paste here] ''' print '{'+str(re.findall('(\w+),',a)).replace('\'','"')[1:-1]+'}' It is not hard to parse the list if you know Python.
•  » » » » 8 years ago, # ^ |   0 I actually typed all of them in 3 minutes.
•  » » » » 8 years ago, # ^ | ← Rev. 5 →   0 You should use text editor which supports regex text search & replace. It should solve the problem instantly, e.g. replace (.*)\n with "\$1",\n
•  » » 8 years ago, # ^ |   +4 there are online QR code decoders that will convert the QR code image into strings of 0 and 1 :)
 » 8 years ago, # | ← Rev. 2 →   +83 The "problem" to problem E: Given that input H -> output H input Q -> output source code Determine if the input sequence is a possible output of some HQ program.The "solution" for problem F seems to be a greedy algorithm, walk to the point with smallest degree each time.I figure these out by reading the AC code of others :P. Anyway, nice contest :D.
•  » » 8 years ago, # ^ | ← Rev. 2 →   -9 input Q -> output reversed source code
 » 8 years ago, # | ← Rev. 4 →   +44 Wow Great Contest I really liked how havaliza was solving problem F if you see his submissions the test that is getting WA is increasing. he hashes the problem and tests it with Yes and No and to get the hash number he creates an array with hash number size. so when the program terminates he understands the hash number. kinda like hacking :DIf he only had a little more time...his last submission : 3449579
•  » » 8 years ago, # ^ |   +4 wow!
•  » » 8 years ago, # ^ |   +6 Can u please explain how did he get hash after making array. The memory usage gives the maximum mem usage among all the cases, so what else it can be? Like when I submitted his soln, all I get to know is a WA on tc 39. Any hints?
•  » » » 8 years ago, # ^ |   +8 he would only create an array on the last case. if you see his code he has used exit(0) on the determined test cases so that the code would not make an array on those tests.
 » 8 years ago, # |   +9 System Testing here ?? fooling continues .
 » 8 years ago, # |   0 The problems were awesome,though I could solve only C and D. A was also easy,but I could not get the logic because my GK is not that good.
 » 8 years ago, # |   -13 Interesting!! Look at the toppest user!
•  » » 8 years ago, # ^ |   +2 Wow, you really carefully Ah !
•  » » » 8 years ago, # ^ |   0 Actually she is the site's admin.
 » 8 years ago, # |   0 Excuse me please, I'm wondering why today's problems don't support practice after contest? Will this measure be canceled later?
•  » » 8 years ago, # ^ |   0 coz its still in system testing phase :D
 » 8 years ago, # |   +2 Best April Fools Picture for me!
 » 8 years ago, # |   0 This was one amaaaazing contest , although — unfortunately — I entered it an hour after it started , I really enjoyed it :)
 » 8 years ago, # |   +1 Wow. Great Contest and Very attractive ideas for problem. specially 290A - Mysterious strings, I enjoyed it. it was harder than last year :Dfor problem E :H --> Prints "Hello, world!".Q --> Prints the entire text of the source code file.9 --> Prints the complete canonical lyrics to "99 Bottles of Beer on the Wall".Plus(+) --> Increments the accumulator.Be More successful. :)
 » 8 years ago, # | ← Rev. 2 →   0 How I'd solve problem E (I didn't solve it during the contest, because I didn't get what was the task :D): realize that if there're q letters 'Q' in the original program, then there must be q^2 letters 'Q' in the output next, if there are h_0 letters 'H' before the first 'Q' in the program, there must be 2h_0 letters 'H' and a 'Q' after that, in the output if there are h letters 'H' in the program, then there must be h(q+1) letters 'H' in the output So it's possible to extract the first quine printed easily (it has length h+q and starts with the h_0+1st letter, in the output), and then simulate its output and compare it to the input.Code: 3450396
 » 8 years ago, # |   +5 Great and interesting problems. Really enjoyed the contest. :D I LOVE MONGOLIA || Би Монголдоо хайртай
 » 8 years ago, # |   +8 Please open practice .
 » 8 years ago, # |   0 Had to work :( Interesting that no red coder was in the top 5!
 » 8 years ago, # |   +16 This contest was awesome!
 » 8 years ago, # |   +3 Will there be an editorial for this contest?
•  » » 8 years ago, # ^ | ← Rev. 2 →   0 Editorial is here.
 » 8 years ago, # |   +4 nice contest :)
 » 8 years ago, # |   +9 i have never seen this type of problem in contest, anyway the problems were challenging..
 » 8 years ago, # |   0 nice one :)