Всем привет)
Уже завтра в привычное время состоится очередной раунд Codeforces #249 для участников Div. 2. Участников Div. 1 мы традиционно приглашаем поучаствовать в этом соревновании вне конкурса.
Задачи для вас вновь готовили авторы Павел Холкин (HolkinPV) и Геральд Агапов (Gerald). Как всегда, мы выражаем свою благодарность Михаилу Мирзаянову (MikeMirzayanov) за прекрасные системы Codeforces и Polygon, а также Марии Беловой (Delinur) за перевод условий задач.
UPD: Распределение баллов по задачам будет стандартным — 500-1000-1500-2000-2500.
Желаем всем участникам удачи, высокого рейтинга и удовольствия от решения задач)
UPD2: соревнование завершилось, надеемся оно вам понравилось)
UPD3: ссылка на разбор уже здесь)
UPD4: Поздравляем победителей!:
1) JiangZemin_JiangHaha
2) Rafbill
3) Yukinoshita_Yukino
4) kuangbin9
5) spartacus
Второй раунд от тех же авторов за две недели? Неплохая продуктивность)
и снова див 2?:)
You have just prepared Codeforces Round 246 (Div. 2) and now three contests after again you!
I think that would be better if you prepared a both division contest instead of 2 Div2 s. These days there are too few Div1 contests.
Anyway, I'm a Div2 contestant.
Hope everyone high ratings. :-)
The contest just after this contest is Div1 + Div 2 contest.
also, it's Codeforces Round #250! :)
Only 6 more rounds till it becomes a big, fat and round number :D.
#11111111b = #255doh, i was thinking about increasing of my rating when i remembered that now i'm in div. 1 :(
An quite important contest for me. Because this June 1st is my last Children' s Day ever:p
I think that Round 250's statement may mention the Children's Day. :)
exactly. But I mean when the system test finishes, it will be June 2ed( or almost) in China! Or I can name it the last rating-change chance.( but actually, I couldn't do well in the past 'important' ones... Crossing my fingers now:)
What does the polygon system do exactly? Does it have anything to do with polygons?
What does the polygon system do exactly? Does it have anything to do with polygons?
Polygon is a system to make life easier to generate problem set with input and output and input validators and more...
not related to geometry polygon
Click here to see it
In Russian 'polygon' aside from its geometry meaning also stands for a place where weapons or some vehicles can be demonstrated and tested.
I see. Thanks!
Your 20th (Div. 2) only contests!!!
OFFTOP
Did you see the innovation in info pages? The highest ratings are now noted near current one and pointed in rating graphics! So, wish everybody increase this indicator! :)
I hope to leave March with my first "Back to green" , waiting too long for this moment
Hope that :)
Best wishes for you... :)
MarchMay :)you did it :)
Nice thing that you keep making contests constantly. You are one of my favourite authors ! Looking forward for the round!
GOOD LUCK!
You have wished us in such innovative way in your last 3 round announcement post...
All the images are also unique... :)
Nice to see that wishes....
did someone notice a "poke-ball" in above goodluck image!! :D
hoping to have another good experience in the contest!!
good luck everyone.
that is our new feature)
OFFTOP
just noticed that now your cf profile also shows what your maximum rating is :D
duplicate comment
Will anyone suggest me to improve my skill. I feel very darkness about my programming skill, rating,etc.
Train , train and train — said Petr — . You also need to have a mentor to tell you if you are training in the right or the wrong way , and find some company who will encourage you to train
Don't be upset, if programming is your passion continue to do it. Some people can't even write simple "Hello world" program! You need just to believe in yourself and you will do anything!
P.S Sorry for my bad English.
I also felt very darkness before, but now I feel very confidence. Just persistence. :)
I'm so sorry for thanking you too late. Actually all are my fault, I'm responsible for all. I'm so sorry. Infinitely numbered thanks to you all. But you see that my performances in all contests that I've participated. It's not only developing my skill, practicing, doing well etc. but also it's the fame of my country, my institution, my trainer(my senior brother), all. What can I do?
well, for starters, u can stop posting the same comment three times!
It's kinda funny to be coding in a village where people are mad at you for not looking after the farms.
P.S.: Don't misunderstand. This is not where I live.
The contest for today was about to begin at 7:30 pm as per written on the contests page.. But it has not started. What is its correct time?
it's 7:30 PM in MSK Moscow time
you can view the time in your region from here
or you can just wait 1 hour and 15 minutes :)
can't you see the countdown on the right?
45 minutes before contest!!
checking winners-to-be of the round? :)
I registered for this and it won't let me submit.
Its saying that I'm not registered.
Do you see yourself in the registrants' list? If you don't, you aren't registered, and you can know it that way even before the contest starts.
Problem B he decided that the number is to small to be. I think it should be too small to be
Pasha decided that the number is too small to BE)
I mean you missed a letter^^(too---to)
I should have accepted the problem D. What a pity...
Wrong answer on pretest 5 ??? (Problem D)
At least I'm not alone who has this problem. I kind of checked everything in my program where a bug could be. But it seems more likely that some bug caused WA rather than wrong solution idea.
I 've found the bug: Assume our triangle is right-triangle at (x,y). If triangle is not "white" in length L, it could be "white" in length L+1.
For example:
Strangely, I have not found the bug in last 90 minutes. And I found it ~10 minutes after contest ended.
Here the answer is 8, isn't it?
Why is 8? I found 7 :S
and i only found 6 :P
how can you find it? can you tell me please?
UPD : why you so rude to me? I just wanna ask for solution :(
Как я понял в задаче Е дан плоский граф, который всегда можно раскрасить в 4 цвета. Но как? Поделитесь алгоритмом.
Третий сэмпл.
Ну естественно, всегда можно, если не учитывать изначальные цвета.
How can I see the result? Or wait until tomorrow? This is my first time using Codeforces. Thank you and sorry for my pool English.
Oh,I'm foolish...
Вообще не понравился раунд. Ну то есть С и D без всякой претензии на идею. Я, конечно, сильно злюсь на себя, что не смог написать D за час, но все же обычно ждешь чего-то на "побольше подумать" от задачи D.
Если подумать, то код задачи Д получается очень коротким. Лично мне гораздо больше нравятся задачи, в которых "подумать" более программисткое. А именно, подумать как коротко написать, как написать без багов.
Если хотели математическую задачу, решали бы Е. :)
Да хороший раунд :) Спасибо авторам!
That was some real fast system testing!
Someone please give a test case where this (Div2 B) solution fails. Can't wait till the system test gets over. Thanks.
EDIT: Nevermind, the system testing was fast and the test cases are now visible.
similar to my initial solution 6746602
failing case:
a = 129,k = 2.correct answer:
912thanks for fast system
So fast System Test! It is very good:)
quick system testing.... :)
I wonder why when I rewrote 6749499, let it run on "10 10 all zeroes" on the custom test, it gave TLE, but when I tried to hack it gave the right answer. Is the testing system for custom test and for hack tests completely different or just random?
Теперь давайте так же быстро рейтинг начислите, как протестили...)
Уже)
Some minutes before the end of the contest I inadvertently locked problem C(my attempt was A and B only).
I saw I did something wrong (variable assignment) and asked the judges to unlock the problem, as I had not seen anybody's code and no one had attempted to hack my solution. I got a NO answer. I understand the decision, however, wasn't my question fair?
Isn't there a way for the contest setters to see whether someone has looked at somebody else's code?
... seconds after the judging ended, I resubmitted and got AC as I expected. Not to happy about judge's decision.
Some minutes before the end of the contest I inadvertently locked problem C(my attempt was A and B only). I saw I did something wrong (variable assignment) and asked the judges to unlock the problem, as I had not seen anybody's code and no one had attempted to hack my solution. I got a NO answer. I understand the decision, however, wasn't my question fair? Isn't there a way for the contest setters to see whether someone has looked at somebody else's code? ... seconds after the judging ended, I resubmitted and got AC as I expected. Not to happy about judge's decision.
Well, there's no reason why your question wouldn't be fair. That's to say, the judges' decision is fair as well :D
Better luck next time!
System testing is too fast Probably because of strong pretests... BTW nice problem set and a successful round overall.... :)
When will the rating change? Will it be a long time?
My rating has already changed.
1698rating……why not 1700:(
Another time a Div2 only contest and 410 unrated users with strange usernames...
i understand ur annoyed about it, but u don't have to take a sword and cut your computer because of that! :D
PS: i'm referring to ur profile pic! :P
weird isn't !!!! the official winners are new users most of div2 rounds !!
Контест был очень хорошо подготовлен, но жаль что у тех кто сдавал задачу C на fpc решение слетело по времени, хотя этот же код отправленный на Delphi 7 брал полный балл :-(
3 человека, в топ5 зареганы менее 5-ти часов назад))) в топ100 таких много)) намекает....
Ибо нечего онли див2 проводить. Лучше раз в неделю (как раньше), но оба дивизиона. К примеру, если убрать всех фейков на сегодняшнем раунде, то я был бы розовым. А так нет... Увы.
Не сильно поможет) Участвовать внеконкурса в див2, не кто же не запрещает
Вне конкурса пусть участвуют. Мы говорим про официальных. Диву1 уже смысла не будет решать в див2, когда у них свой раунд есть.
Нет, неправда. Лично мне прорешивать див-2 раунды есть смысл. Жаль, не смог поучаствовать в сегодняшнем
Rate-up!^^)
Is it possible for problem setters to try the problems in Java before setting the time limit?
For problem C I got a "Time Limit Exceeded" in the contest.. Changed using "System.out.print" to using a StringBuffer after the contest and it passed.
Same thing happened last contest, I got a "Time Limit Exceeded" probably just reading the input (even though I use a BufferedReader).
Рисовать кардиограмму — бесценно
My wrong algorithm code got accepted for problem A! Check detailed info in my blog: http://codeforces.me/blog/entry/12481
why did I get WA on the problem B tescase 40 if it gaves me the correct output running in my computer,please help. http://codeforces.me/contest/435/submission/6750836
In this part of your code :
That you determine the maximum index
lyou can go forward and pick some characters,You have a problem when
b+1 < a.length()butp+b+1 >= a.length()then you access somewhere in memory where you didn't initialize.This can cause run-time error or some unwanted value. Here there was a
'n'in judge system memory after your string characters , and you bring that in your string.quick fix :
l=min(p+b+1,a.length())good contest and good problemset. only thing missing was hacks.
hope to see this level of problems with a few more hacking chances in ur next round! :)
what's the meaning of "skipped"?
Skipped means your solution was not judged probably because you submitted it twice or some other participant had the same solution.
Round Stats
this code gives WA answer on test 5 for problem C but in the test button it gives different answer for this test case ?? My submission