Elimination Round will start today, 14:30 (UTC) and only contestants who have passed Qualification Round will be eligible to participate.
Score for each solved problem is calculated based on these values:
- n = No. of accepted submissions
- t = Contestant's submission time
- p = Number of contestant's wrong attempts
To receive the latest news fast, follow us on twitter: @bayan
Update 1: The Elimination round is over, and let's face it: It was far from good!
Yes, we're aware of all the issues, and we know that nothing is more nerve-racking than facing those issues during a competitive contest. So, first thing first, we'd like to sincerely apologize for all the inconveniences caused.
In last hours, we thought that the contest has become too hard, so we made a major wrong decision: omitting a hard problem and adding a simple problem as our first question without enough time. Hint: never make any changes to the problem set in a hurry.
Update 2: Editorial is on the way. Source codes will also be avalible in a few hours.
Update 3: Unfortunately we have found some cheaters. As mentioned before they will be banned for ever from Bayan Programming Contests.
Update 4: The editorial is now available.
Who are the winners of T-shirt of Qualification round?
T-shirt winners will be announced after our elimination round all together.
Thank you!
When will I see the countdown?
Elimination round is going to be held on contest.bayan.ir, so you are not going to see the countdown here. Elimination will start in less than 1.30 hour.
But when will I see the countdown on contest.bayan.ir?
There is one already!
I see only Available soon
I saw only Available soon
shouldn't it be something like t/T instead of t/500?
No.
but 't' is not number — it is amount of time. Did you mean that t is I don't know.. number of minutes from start to submission?
and will we know about WA/AC immediately or after contest?
yes, t = time of submission in minutes. and yes, you will see your submission verdict immediately.
Hi, I'm not sure this is a good place to ask, but I've started receiving email contest announcements in Russian. Can I switch that back to English somehow?
Also: Is there a help forum somehow that I can't find or is this the only way to address you?
Best, Esuhi
We are not sending Russian emails. Probably Codeforces is sending them for Russian contestants.
how can i submit problem
The same way you did it in qualification round.
How to Solve and Submit a Solution
150logn ?
I know that O(logan) = O(logbn) regardless of a, b values (assuming they are greater than 1), but logan ≠ logbn :). Is this log2? Or natural logarithm? Please clarify.
it is logarithm in base 2.
To make it clear — we have full feedback, yes? I mean, immediately after submitting file, I will be informed whether is this correct output? If so, am I right that final results will be immediately available after the contest? No systests, no freezing, right?
Yes. Scoreboard will be valid all the times.
What a great information :)! First contest where I won't fall 500 places because of some stupid bug in a hard problem : p.
in this formula n is no. of accepted submissions of this task til my submission or in whole contest?
It was written solving 1 will qualify you to the elimination round .. I solved two .. Yet showing not qualified ?
the bottom left corner always shows:
Disconnected. will retry in X seconds
Doesn't it overlap with CookOff?
I really like the Ui of the Bayan website :)
Sorry to say this, but it is too slow, just like the Shortcut Round. I cannot log into the contest area no matter how hard I try.
Same thing here :/ It disconnects all the time.
I can't see any problem :(
as I cant :(
Connecting =(
Contest has started, I could connect ("Receiving live updates"), yet the Problems tab remained empty. Are we solving 0 problems instead of 6?
Nothing works, can't see any problems.
The contest time countdown started, we're 2 minutes into the contest, but there are still no problems in the place where was the placeholder.
Is it working for anyone? In theory the contest started already but i can´t see any problems... it only tells me "Disconnected, will retry in x seconds"...
Problems are visible now
I just tried to solve a problem but it says Firefox can't find the input file.
I see problem but I cannot download input file!!!
Instead of providing me with an input, it says "Webpage not available".
Can't download test input, and my time is running out. Come on guys, why are there bugs again. It's a time-penalty competition so such bugs are crucial to results :(
EDIT: Will penalty from first submission be removed?
Hardest problem: how to get test input
Edit: Even after announcement all I get is a blank "Untitled" page... :/
This contest arena is begging me to switch to CodeChef Cook-off in 50 minutes.
It's the most awful contest which I've been participated ever(
My ticket has expired because site was down.
Problem B. Is the time in minutes or hours or something else?
I think it's in second
Sent a clarification more than 10 minutes ago, still no answer. Where have you read that the time is in seconds?
because in the last testcase, the time is 28801, 8 hours = 28800 seconds
My solution has been pending for 10 minutes, is it only me?
Nah, definitely not only you.
Mine for 17 minutes :(
I don't know why problem A is so hard to get accepted, although it is a very easy one.
same here, I have no idea why I keep getting wrong answer
Seems easy but, I think some description is missing, so lots of WA :(....... I'm gonna participate Codechef-Cook-Off !! Bye bye BAYAN !!
Почему-то жутко вспоминается эта мелодия на протяжении всего контеста...
How must lines end in my output file?
\n
\r
\n\r
Или я просто не умею решать камень ножницы бумага? =))))))
Я пробовал "\n" и "\r\n", с и без перевода строки в конце, не помогло.
Мне тоже не помогло. Может проблемы с кодировкой? =)
CookOff, there you go :D
A — hardest problem ever. Only 256 right answers out of 2,5k submissions at the moment. DAFUQ IS GOING ON!? That is so embarassing!!!
It is getting harder and harder, now with 50 accepts.
You too(, Brutus?) :D
In fact, due to this, I harbour a deep suspicion that the system is rejecting some type of correct solutions. But that can't be checked until after the contest.
If someone ever ask me about the definition of failure I will tell him "Bayan contest".
I've submitted the same code 10 times....and the last time it has got Accept!
=))
lol I did the same, but got accepted in the 8th one xD
What's going on?
"Question A will be rejudge". :D
Problem A was rejudged in the middle of the contest, and it went down from 500+ solves to just 36. (That's a 1% success rate for submissions.) There's a crash every 3 seconds, and test data doesn't load half the time. This is probably the worst contest ever organized...
I'd say, that was second worst contest ever... because of their "shortcut!" round.
Should I input/output to file or standard input/output ? In the qualification round I used stdin/out and still got AC. Now they say I need to use file input/output. But what file ?? For input it's probably like "A.txt" but whatabout output ? Also, sometimes it's really hard to submit/download input. And while I was writing this comment, my problem A got AC with the exact same code of 8 previous attempts :| Maybe we should hold another elimination round, on codeforces platform instead ?
Is there a scoreboard for spectators?
http://contest.bayan.ir/en/contest/elimination_2014/scoreboard/
Thanks for the contest [already], but I'm not going to participate next time. Even after this comment it seems that platform doesn't work well, so what is the point?
Their Last Year Contest Was Quite Good But Today... !!! Bayan, Hope To Have a Good Reason For This
Hey, did you use the code from this problem?
Making your company famous: you're doing it wrong.
If it takes place on your platform next time, I'm definitely not participating.
me too :(
"Question A will be rejudge."why?
Does Problem C has a tricky solution or there is a classic way to do it?
Are you seriously asking about solution during the contest -_-...?
I am seriously asking during the contest, while waiting for the answer after the contest :)
I'm not gonna partecipate again! I spent two hours on the first because of wrong answers, but after all they were all accepted!
I've spent two hours with first problem too :( I'm not implying I would have solved more tasks but it's disappointing.
Well I think I were near to a solution for C, but I had no more time left:(
And I gave up the contest after repeated wrong on A and went to participate in codechef cook off. Now I am knowing that I had passed A
me too :|
how I solve problem C?!
Finished.
but i like know a bout it !
Let's try to construct the path backwards. The inverse path begins on the biggest number of the input.
Suppose you have already stepped on some tiles, and you need to step on a next tile. Note that as we're going backwards, the final number on a tile is defined by the first time we step on it. For this reason, when going to the next tile, you can only use the tiles that you have already stepped on previously.
So do a BFS from the tile you're on to the next tile you need to step (using only tiles already stepped) and check if you can reach the next tile in the number of steps required. If the bfs returns a smaller distance than required, you can add any multiple of 2 to the number of steps in the path by simply going back and forth between two squares.
thanks a lot.
Provided two suitable squares exist.
If you are checking in order of increasing values using BFS, two suitable squares will always exist unless it is the last one(which is the same condition as two highest values on the grid must differ by 1).
Explicit BFS is not really needed. You just need to prove that a backward path exists, you don't need to find it. The solution to the problem is "YES" if and only if the following 4 conditions hold: - (1) All numbers are different - (2) Every pair of neighbors have different parity. - (3) Every tile, except the MAX, has a larger neighbor. - (4) The MAX tile has a MAX-1 neighbor.
Condition (3) ensures you have a backward path from any tile other than the maximum, and condition (2) ensures this path is of the right parity.
UPDATE: Forget this... it's wrong... BFS is needed, because otherwise the path may be too long. Example: 1x4 grid with values 2 3 4 1.
Consider following grid
1 200 101
300 301 2
All your conditions are true, but answer is NO
one positive fact:
problems were interesting.
Hope for a better platform.
Considering the amount of problems with the platform(slow, those rejudges etc..), the number of participants receiving t-shirts should be increased by 10-20 :D
Your comment will get 20 likes, and I'm one of them giving! ;)
Why don't you hold off the contest on Codeforces?!
When such a great system like Codeforces is available what's the reason to don't use it and instead, use a weak, slow and totally bad system like yours?
I really hated the delay, the file input output, your slow system and many times not loading, you had file input output but still you had problems with your judging for problem A, you didn't answer too clarifications and ...
Can people who won a T-shirt before (in ShortCut, Qualification, WarmUp Round) win T-shirt again in this contest?
http://codeforces.com/blog/entry/13542#comment-184595 — here I said that according to weird (ans stupid) rule "one country — one finalist" I think I got higher chances to qualify than without it, but it turned out, that I was in TOP20, but Eryx was better, so it is exactly the opposite -_-. This is my first time I ended in TOP(number of finalist) in qualifications to some onsite competition, but I didn't qualify, because of that ridiculous rule :(!
In problem C — GridHistory — Can anyone show me a path that is compatible with the first sample? (2x2 grid, first row 4,11; second row 7,12), because even after computing an exhaustive search I haven't been able to find any... I don't know what I've done wrong...
UPDATE: I misundertood the problem completely :( I interpreted it as "When he enters a cell, he erases the number written in that cell and writes the last number he has written ON THAT CELL plus one", rather than "the last number he has written ANYWHERE IN THE GRID :_(
In steps:
You can go over a grid space more than once. So starting from the top right square the sequence of operations is: DLUDUDRUDUD. (Where D = down, L = left, etc.)
on 1-based index : starting at time t=4: t=4: 1,1 t=5: 1,2 t=6: 2,2 t=7: 2,1 t=8: 2,2 t=9: 1,2 t=10: 2,2 t=11: 1,2 t=12: 2,2 basically each cell can be visited any number of times(the last visited time is its final value :P )
I misunderstood the question. I thought it said he rewrites the number with the original number on that cell plus one....
Looks like you made the same mistake.
Indeed.
I made the exact same mistake and lost top 20 because of it. This is why contests usually have explanations of the sample input.
Ranked 4, but I can't go to final. What a sad story. Congrats to hos.lyric and sillycross. And I think Hiroto Sekido is much more unlucky than me. T_T
I think because hos.lyric had made it to finals using Shortcut round, laycurse has also qualified for the finals.
Oh... It seems I'm the unluckiest. T_T
How to solve F :>?
Question to organisers. In case someone from TOP-20 country-wise doesn't accept onsite invitation, do you offer this place to somebody else or no? The reason I'm asking is because my country seems to be TOP-21 if I calculated it correctly.
out of topic: I calculated my position and I'm TOP-22 if I did it correct, and I'm positioned 44th globally.
Need to clarify that the flag on 43th, aside South Korea, is a Hong Kong flag instead...
UPD: Sorry for ambiguous but I mean myself(whose flag is Hong Kong), along with a South Korean, (While not Vietnam), are on 43th place.
Fixed.
Looks like Afghanistan.
Ehm, 17, places 31(me) and 42th are not Hungary but Bulgaria. Google the flags, it's the same colors but different order :P
Fixed
Looks like places has changed. Maybe you need to update this chart.
Updated.
The platform is less terrible than for the shortcut round, still terrible.
The problems are interesting, except the straightforward implementation tasks A, B and E.
Apologies for having the wrong flag next to my name on the scoreboard, I only now realized that the nationality is relevant, not the residence.
About the onsite finals, https://www.gov.uk/foreign-travel-advice/iran/safety-and-security does not sound very reassuring. What is your opinion?
What is your nationality? Again, the reason I'm asking is that because it may move my country from TOP-21 into TOP-20 :)
Serbian instead of Swiss. Neither seems to affect anyone else's top-20.
Wrong place for comment
Double post
Let's take a look what this site says about your own country: https://www.gov.uk/foreign-travel-advice/serbia/safety-and-security ;)
Sounds accurate, and slightly less worrying than Iran. It's not my intention to offend anyone.
This phrase "Kosovo’s independence remains an emotive issue for many Serbs." doesn't sound accurate to me because Kosovo is not independent country. Moreover, it's an interesting question — organizers didn't specify what nationality means in profile settings and didn't specify what country means — for example, Hong Kong and Chinese Taipei are Chinese provinces in my opinion so do people from those regions need additional spot in the final?
Not to start any fights or offend anyone, but in my opinion Taiwan and China are different (I think most people who were on this year's IOI would agree) so they should get different spots in my opinion. However the question what exactly does nationality mean is still valid.
For the purpose of this contest, a nation is what appears on the dropdown list on Bayan's website. If it's not on the list, it's a province.
For the purposes of everything else, this is a complicated question and this is not the place to discuss it.
How to solve D? Did anyone prove it this time? :)
The visible surface is at least the sum of the highest towers in each column, plus the highest towers in each row, plus the top surfaces.
For each k, you want to minimize the number of columns and rows that contain a tower taller than k. Put the k highest towers in the smallest (by perimeter) rectangle that can contain them. This rectangle is either a square, or has sides that differ by 1, or has one side length equal to min(n,m). So, this is the lower bound for the area, and since we can actually do that for all k at the same time, it's also the upper bound.
To calculate the number of ways, let's say you have the number of ways to pack the tallest a*b towers in an a*b rectangle, with a<=b, and want to calculate the number of ways to pack the (a+1)*b tallest in an (a+1)*b rectangle. You can extend the rectangle in either 2 or 4 directions (4 when a=b<min(n,m), 2 otherwise), and arrange b towers along the side in 2^(b-1) ways.
About the number of ways, how to handle the part where the a*b rectangle lies on one of the edge (therefore only 3 directions to extent)?
Don't even consider the n*m grid. Imagine just extending the rectangle (which is floating in space) until it has size n*m, and then placing it on the grid in the end.
Aw I just found out that. Looks like I lack creativity :c...
how to solve E?
Do the steps n-1 times: find out the edges that connect a new tower(toweres not yet filled with water). Choose the lowest cost, let the cost be x, then we make all other towers that is filling with water height at least x. The time needed is the total volume of water at that moment.
Who are the winners of T-shirt?
Will another additional Elimination Round?
nerve-racking -> nerve-wracking
first thing first -> first things first
apology -> apologize...
BTW so happy that I didn't participate.
But somehow you still care writing here...
I think either racking or wracking works.
Will there be any editorial? I'm really curious about F.
Was this contest organized by same people as 2 years ago? I have a feeling that this is coming from completely new group of people which have too much ambition without anything to back it up.
T_T
when you send T-shirts to winners?
Did they announce t-shirt winners ??!!
I think I didn't make a mistake, that I didn't participate in this contest again :) ( http://codeforces.com/blog/entry/14185#comment-191632 ).
When are you exactly going to announce the T-Shirt winners? cause today is about to finish and according to twitter you'll be announcing it today.
It seems that not only the platform is slow...
Some duplicated accounts and a few more cheaters detected. Final rankings and tshirt winners will be announced soon.