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 CCC 2011 - Are you ready?
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A.J




PostPosted: Wed Mar 02, 2011 11:49 pm   Post subject: RE:CCC 2011 - Are you ready?

Ah yes, this old argument again. Well, I believe that this shouldn't make too much of a difference f the largest testcase had been something a bit short of 1000 (like 600), but 25 is a bit too small. The O(2^K) bruteforce would have sufficed like antybash mentioned, and I don't think that this is fair to the people who solved #5 but made some error on another problem but still received a lower score than someone who bruteforced #5.

On top of this, there is an error with testcase #9 for #5. The input specifications state that there will never be a run of 1's of length four or more. However, on the 9th testcase, the last four numbers are all 1's. So the required answer of 2 could also be a 1 (as one could assume that all the lights switch off instantaneously).

These errors shouldn't have occurred on a contest as privileged as the CCC. Though I doubt rectifying these errors would have made any difference to the results of the contest.
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mirhagk




PostPosted: Thu Mar 03, 2011 4:47 pm   Post subject: RE:CCC 2011 - Are you ready?

I litereally saved myself from a brute force method on number three in the last 2 minutes.

I originally had the 5x5 cell, with each having links to the 5x5 cell in it.

This meant 5^m*5^m memory, which failed above m=4.

Then I realized in the last two minutes that certain cells did not need to be zoomed in (Alot actually) so I saved myself in the last two minutes.
Shanethe13




PostPosted: Thu Mar 03, 2011 5:46 pm   Post subject: Re: CCC 2011 - Are you ready?

Drat. I think I may have screwed up question 3. I had a working solution, but I commented out one of my lines to test something, and I'm not sure if I ever uncommented it afterwards.
RandomLetters




PostPosted: Thu Mar 03, 2011 6:18 pm   Post subject: RE:CCC 2011 - Are you ready?

I'm curious to see what a fast solution for S5 is.

I screwed up S3 by forgetting to raise 5^m when modulus-ing OTL
A.J




PostPosted: Thu Mar 03, 2011 6:48 pm   Post subject: RE:CCC 2011 - Are you ready?

I posted solutions and analyses to this year's Senior pack.
Shah-Cuber




PostPosted: Thu Mar 03, 2011 10:33 pm   Post subject: Re: CCC 2011 - Are you ready?

54 ... missed a few cases on S3 and didn't have enough time to finish S5. Guessing the Stage 2 cut off this year is going to be > 60.
Dratino




PostPosted: Fri Mar 04, 2011 10:03 am   Post subject: Re: RE:CCC 2011 - Are you ready?

A.J @ Wed Mar 02, 2011 11:49 pm wrote:
Ah yes, this old argument again. Well, I believe that this shouldn't make too much of a difference f the largest testcase had been something a bit short of 1000 (like 600), but 25 is a bit too small. The O(2^K) bruteforce would have sufficed like antybash mentioned, and I don't think that this is fair to the people who solved #5 but made some error on another problem but still received a lower score than someone who bruteforced #5.

I'd be one of those people who brute-forced it and got a better score. And the wrong way, too. I feel sorry for those people who did get it right. It definitely was unfair.

Quote:
On top of this, there is an error with testcase #9 for #5. The input specifications state that there will never be a run of 1's of length four or more. However, on the 9th testcase, the last four numbers are all 1's. So the required answer of 2 could also be a 1 (as one could assume that all the lights switch off instantaneously).

These errors shouldn't have occurred on a contest as privileged as the CCC. Though I doubt rectifying these errors would have made any difference to the results of the contest.

Actually, I gained 2 points because of the corrected testcase, raising my score from 70 to 72 >_>

But yes, I agree that the maximum of 25 was kind of strange.
ultimatebuster




PostPosted: Fri Mar 04, 2011 7:13 pm   Post subject: RE:CCC 2011 - Are you ready?

Anyone know when they're going to release the results for this thing?
A.J




PostPosted: Fri Mar 04, 2011 7:22 pm   Post subject: RE:CCC 2011 - Are you ready?

It will be another few weeks, I am afraid, as they haven't received all the results from the schools yet. After having received them, they then have to take a further look into the seniors and juniors who scored => 40 and => 55 respectively. So it will take a while.
ultimatebuster




PostPosted: Fri Mar 04, 2011 9:21 pm   Post subject: RE:CCC 2011 - Are you ready?

What makes them change the score your teacher gives you? Assuming that your teacher did everything correctly.
Sorry I'm very new to this (so's my teacher lol).

Also 1 thing, for the senior input files, how do you read them? like s1 filename in command line? Or how does it work? I didn't take the senior one so I don't know.
A.J




PostPosted: Fri Mar 04, 2011 10:22 pm   Post subject: RE:CCC 2011 - Are you ready?

They make sure that you didn't merely output the test data (i.e. cheated), etc... If your teacher didn't make any mistakes, you should be fine.

For the senior pack, input is from the file 'sX.in', where X is the problem number.
ultimatebuster




PostPosted: Fri Mar 04, 2011 11:06 pm   Post subject: RE:CCC 2011 - Are you ready?

Does that mean the marker has to change the input file name to sX.in every time? That seems annoying and error prone.
A.J




PostPosted: Fri Mar 04, 2011 11:08 pm   Post subject: RE:CCC 2011 - Are you ready?

Well, I created a program to do it for me for some of them, and for others I merely ran them on my roommate's online programming judge. But yes, you would have to change the file name each time.
apython1992




PostPosted: Fri Mar 04, 2011 11:44 pm   Post subject: Re: CCC 2011 - Are you ready?

Wow this sounds like a lot of fun...I really wish I knew about it in high school.
A.J




PostPosted: Sat Mar 05, 2011 1:30 am   Post subject: RE:CCC 2011 - Are you ready?

You know it's never too late to get into problem solving. There are tons of online judges and contests that you could write. I personally know of many people who have done this.
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