Привет, Codeforces!
24 февраля 2015 года в 19:30 MSK состоится очередной раунд Codeforces #293 для участников из второго дивизиона. Традиционно, участники из первого дивизиона приглашаются поучаствовать в соревновании вне конкурса.
Это мой второй Codeforces раунд, и я надеюсь, что Вам понравятся задачи, и все пройдет хорошо.
Хотелось бы сказать большое спасибо Максиму Ахмедову (Zlobober) за помощь в подготовке задач, Марии Беловой (Delinur) за перевод условий на английский, Михаилу Мирзаянову (MikeMirzayanov) за замечательные системы Codeforces и Polygon и за идеи некоторых задач, а также моим дорогим друзьям Павлу Холкину (HolkinPV), Артуру Свечникову (ikar) и Виталию Кудасову (kuviman) за прорешивание задач.
Раунд будет немного необычным — участникам будет предложено шесть задач и два с половиной часа на их решение.
UPD Разбалловка задач 500-1000-1500-2000-2500-2500. Всем удачи!
UPD2 Соревнование завершено! Всем спасибо!
UPD3 Разбор вы можете найти здесь.
UPD4 Поздравляем победителей!
a little bit late announcement but i hope system testing won't be late :D
Unusual Round... Hope something fun!!! Best of luck to everybody!!
And Hope for easy problems :D
Hope for interesting problems!
hope for div.1 :D
I told to my boss that i would participate on a online contest on codeforces and he was agree, life it's beautiful :P
still specialist in 35 contest... u need upsolve problems
He has very busy schedule due to job. Atleast he finds time to participate. That makes him a great person
It's special contest to celebrate CF's 5 year anniversary? :)
Codeforces has had an excellent start, and I'm sure it will grow and continue to become better in the future!
On behalf of everyone, thank you for this wonderful site!
Actually it is not a special anniversary contest. But I'm personally helped with ideas for the problems. I hope you will like them :-)
oh!I hope I won't be wrong in the system testing!
Good luck to everyone! May the best coder win!!!
Then you out of equation
Let's see!
I guess this is because you are going to participate, right?
If i participate and if you in my room, I write stupid code which fails boundary cases, you may hack my solutions and be no. 1
So pray that i participate.
Plot twist: He's atheistic.
I hope you don't win. You are one of those cheaters from division 1.
Am I only one thinking that today special for I_will_win_a_div1_round we need Sorry_I_will_win_a_div2_round?! ;)
Yes, only you...
I think YES, you are the only one or maybe there are another confused guys so I will explain. I'm not somebody like sorry_dreamoon. I am just a normal programmer who has got a goal to win a Div2 contest. And I will do it! Note that I will win a div2 round != I will win Round #293 :)
nope, i am the one who will win this round.
btw im definitely not a div 1 user
div2 contestants looking at your conversation:
Okay, good luck with that. I'm not saying that I will be the winner, I just said that some day I will win a Div2 contest. And once again — I am just a random programmer, not someone pretty good!
Not really random, P_Nyagolov.
come vs no ks
your looks handsome and thanks for prepare a wonderful contest maybe. GL&HF.
I'm gonna be the contest King, and win this round :D
say hello to the one who is gonna get the first place(me)!
I_Hate_This_Type_Of_Coders
I think you're going to forget about becoming the winner for jenabe_haghani(Haghani), since he is registered for this contest.
You know Haghani is gonna become an unofficial participant so he can't officially win the round
You can use this tag :)
"Happy birthday codeforces"
RIP not-out-of-screen images.
link for picture.
The number for the order seems to be in a mess?
Best of luck to everybody
Забавный парень
Ох уж эти смурфы
I am so sorry for hack's !;)
Most hacks in Problem A ever.... So weak pretests...
Well I think it was intentional ;)
Great! I just love those contests full of hacks :D
very Bad contest
I wonder why there isn't syntax highlighting in the source when they are displayed for hacking. That would make it a bit easier to understand the already horribly obfuscated codes people submit here.
Problem A was awesome :) . Got my locked code hacked, but still got 700 points from hacks :D
What are the hacking testcase ?
az by
I hacked around 10 solutions with this case:
aaz
bbb
A lot of people missed that 'z' :D
Thanks for the fast editorial!
Many bugs in problem E, I did ternary search in every sequence of '?', someone else? but I couldn't finish this is my code Your text to link here...
I also wrote ternary search for this task. Here is my code : 10006534
Very-very funny contest :) even though I didn't get good result.
Problem A: I solved it <10mins, and I solve B <1h 20m.
But when I see the standing, I'm very-very embrassed... there is TOO MANY hacks in Prob A.
So, I think: "I should try hacks, too!" and I tried hacks and got 2 success and 2 fails.
And I checked my rank is > 900... then I tried to solve C, and I solved it in 02:22 (8 mins remain..)
I think my C solution is veryveryvery complicated.. I can't understand my algorithm fully. (a bit of luck? :> )
It was very funny and interesting contest. Thanks for contest problem makers :)
P.S. I'm sooo nervous for system testing :<
P.S 2 — The fastest systest ever! Wow..! I just got rank 1232, and only B correct. I didn't think of long long in Prob C...:<<
Did you use long long for C? Some people in my room forgot about it and they got hacked by me :D
No, I didn't.. but is it essential? why..?
If you're right, then I will lose about 600 points... goodbye my blue nickname :<
I just checked my logic is completely right (by editorial)
but I didn't use longlong.... omg
I'm very sad :< My critical mistake..... Because of my critical mistake, I lost my blue nickname
Now you'll never forget to use long long, and get it back next contest :P
Yeah, I will... and I should..
I submitted the new solution using long long (nothing changed except longlong), and I got AC....
Do not be sad! Next time you won't forget about this and you'll hack those who will forget it :D
Same mistake. :'(
This contest was awesome! Thanks!
first time ever was hacked, A problem(
Fastest systest ever!
Wow, this is the first time I ever seen system test can go that fast, about 1min
The winner solved 4 problems and 27 hacks, and 2nd contestant solved 5 problems and +8 and -5 hacks.. this is already very rare situation, but additionally, solvers of 6 problems are in 7th place.. very very very rare contest..
http://mirror.codeforces.com/contest/518/hacks/137892/test I think I was hacked against rules. In C statement is written: "Each integer from 1 to n occurs exactly once among a_i." How it is possible and what to do?
Don't see what's wrong with the test case?
Each integer from 1 to n still occurs exactly once among "a_i". You can have any values in b_i.
I hacked your solution with this case. There is nothing against the rules, you can open an app multiple times :P Your solution has an undefined behavior in this case :P
Ok I understand.
Thank you very much for a wonderful contest!
Who do you think has the best implementation for the last problem? I just bruteforced it with a bunch of functions that are almost identical — 10005221
Nice contest, by the way, although it wasn't hard.
Finally, purple after 65 contests! Thanks for this round. System testing was also quick.
thanks fcspartakm ,finally your contest made me purple :)
Could somebody help me with DIV 2 B ? I failed at 30 system test http://mirror.codeforces.com/contest/518/submission/9990527 , but input isn't visible
Change the type of small[] and big[] from char to int then got accepted. In Java, char is 16-bit. 16-bit's maximum is 65535, lower then the input size(2*10^5).
I'll just leave it here
You could ask for A first :D
after I gave no response, he PMed this: 10009385. I believe CantGetAnyWaWhyIamSoWise is not his main account.
I believe it was CMaster's clone. He was in my room, he realized I struggle with A, he submitted this 9986973, and he didn't solved C. What a shame.
I wish I never attempted the A problem :\
Am I the only one who sees nothing over here: http://mirror.codeforces.com/contest/518/hacks ?
UPD: And it's fixed now.
Very interesting
Could authors of this contest kindly share test #24 for the problem E? Thanks in advance.
Finally, the number of submissions reached 10000000!
I'm the champion of this round.