I did the junior contest, finished J1-J3, and J5, but one test case for J5 didn't work
And was J5 the same question as S5? Cause I know J5 was in the senior contest too
Computer Science Canada Ccc 2008 |
| Author: | zylum [ Tue Feb 26, 2008 8:44 pm ] |
| Post subject: | Ccc 2008 |
Hey guys, I was hoping for someone to scan the problem set for this year so we can discuss solutions and such. If it's too early to post them for some reason, let me know as I'm not up to date with CCC news. |
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| Author: | StealthArcher [ Tue Feb 26, 2008 8:44 pm ] |
| Post subject: | RE:Ccc 2008 |
It's too early. Some places had snow days. |
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| Author: | waleedalidogar [ Wed Feb 27, 2008 12:26 am ] |
| Post subject: | Re: Ccc 2008 |
So yes i did finish the ccc i only got to finish uptill 3 perfectly but 4 and 5 were out of my reach wat about others??? |
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| Author: | r691175002 [ Wed Feb 27, 2008 1:11 am ] |
| Post subject: | Re: Ccc 2008 |
Got up to S4 in 2:10 but couldn't even get a hold on S5/J5. After giving up on S5 I made up some test cases and am moderately confident in my solutions. Being my first contest I started panicking at S3. Because of that it took me an hour and three tries, which was extremely frustrating since I had done so many similar problems before. Just for some comparison, 9 people at my school took the test, 3 Junior, 6 Senior. All three juniors made it to J3 and then got stumped, all other seniors made it to S2, and some may have gotten semi working solutions for S3. One senior gave up after looking at S3 and switched to the Junior test, getting to J3. We hadn't done anything remotely similar to algorithms/problem solving in class so I was essentially the only one with any preparation. Just remember to keep it vague guys. |
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| Author: | syntax_error [ Wed Feb 27, 2008 4:39 am ] |
| Post subject: | RE:Ccc 2008 |
"Just remember to keep it vague guys" how bout nothing; I am sure you are not dieing that badly to talk about it do hold yourself; time will come and Im sure pll will help you with full solutions. DO wait and be fair. Any Mods want to lock this just in case someone doesn't wish to follow the rules and posts a "revealing" comment. Just my thoughts. |
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| Author: | sparta [ Wed Feb 27, 2008 7:07 am ] |
| Post subject: | RE:Ccc 2008 |
shh people. waiting till the 28th wont kill anyone. |
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| Author: | Euphoracle [ Wed Feb 27, 2008 7:58 am ] |
| Post subject: | RE:Ccc 2008 |
I did up to J4 confidently, but J5 really threw me. I had it all working, but there was just 1 test case on the sheet and 1 that I thought of on my own that it wouldn't get right. I never would have thought that I forgot an expression that I later realized would solve those two correctly :\. Oh well. J1->J4 I found easy, as stated; however I spent upwards 20 minutes trying to debug J4 only to realize that I had lost a lot of time, and the error was a mismatched less-than sign. What a waste :\ Who knows, perhaps if I didn't do that, I might have had enough time to finished the fifth. |
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| Author: | fantasy [ Wed Feb 27, 2008 4:08 pm ] |
| Post subject: | Re: Ccc 2008 |
Well I got s1-s4, then had no time for s5 But after i got home i tried i realized i did s3 and s4 wrong =[ |
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| Author: | Fusha [ Wed Feb 27, 2008 4:12 pm ] |
| Post subject: | Re: Ccc 2008 |
I did the junior contest, finished J1-J3, and J5, but one test case for J5 didn't work
And was J5 the same question as S5? Cause I know J5 was in the senior contest too |
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| Author: | Tony [ Wed Feb 27, 2008 4:24 pm ] |
| Post subject: | RE:Ccc 2008 |
When I was writing CCC a few years back, last of Junior overlapped with first of Senior. So J4 and J5 would be S1 and S2. |
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| Author: | sparta [ Wed Feb 27, 2008 4:31 pm ] |
| Post subject: | RE:Ccc 2008 |
i still can't understand why they had the same question for s5 and j5. Now i regret not even reading it over at the time cuz i thought s5 would be insanely hard >.> |
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| Author: | Fusha [ Wed Feb 27, 2008 4:48 pm ] |
| Post subject: | Re: RE:Ccc 2008 |
sparta @ Wed Feb 27, 2008 4:31 pm wrote: i still can't understand why they had the same question for s5 and j5. Now i regret not even reading it over at the time cuz i thought s5 would be insanely hard >.>
That's what I thought. It's kind of weird. And I heard a lot of people (seniors) didn't get S5, it was pretty tough. |
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| Author: | Clayton [ Wed Feb 27, 2008 5:01 pm ] |
| Post subject: | RE:Ccc 2008 |
Yes, S5 and J5 were the same question, the test cases for J5 were much less strenuous than those for S5 however. |
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| Author: | stde [ Wed Feb 27, 2008 6:04 pm ] |
| Post subject: | RE:Ccc 2008 |
i think this years senior sets are harder than last year since [mod edit]please don't mention which algorithms are required by each problem until we get the all clear that all schools have finished writing the contest [/mod edit] for me, i felt s5 is easier than s4. i counldnt think of any optimal solution for s4 anyone has idea on how to do s4? |
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| Author: | whlue [ Wed Feb 27, 2008 6:45 pm ] |
| Post subject: | RE:Ccc 2008 |
I got S1-S3 done pretty quickly, S4 threw me off for a while, after trying to figure out a ton of stuff about it which was wrong after an hour of pondering, but I figured out an answer for S4 which was blatantly obvious and only took me 10 minutes to write, and test. Unfortunately, I didn't get a chance to do S5 because of the hour or so wasted from pondering over S4. I'll divulge my solutions for them I guess when we get the OK that we can start discussing it. |
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| Author: | whlue [ Wed Feb 27, 2008 6:48 pm ] |
| Post subject: | Re: RE:Ccc 2008 |
sparta @ Wed Feb 27, 2008 4:31 pm wrote: i still can't understand why they had the same question for s5 and j5. Now i regret not even reading it over at the time cuz i thought s5 would be insanely hard >.>
My guess is that too many people got perfect in the junior last year (since it was a pretty easy problem set), so they wanted to spread out the range of the people who scored high. |
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| Author: | Sane [ Wed Feb 27, 2008 7:13 pm ] |
| Post subject: | RE:Ccc 2008 |
Hi guys. I'm a high school student from Ottawa. I signed up for this forum because it appears to discuss computer science competitions and algorithms-- two things I love to study. I'm looking forward to talking to many of you. I finished the senior competition in 90 minutes. Question #4 was the hardest by far. The rest were good. But I think 2008 might have been the easiest year so far, next to 2007 and maybe 1996. So I spent the last 90 minutes of the competition checking and rechecking and checking it again. And now I'm so bloody anxious to get it marked. Haha. I'll give the solutions for 2008 when we get the go ahead from the other schools. The last question (S5/J5) was a duplicate of a previous stage 2 question. I'm not sure if I should disclose any more information, since that might be going too far. Oh: And by the way, the reason they used #5 for both junior and senior is because the input restriction is specifically tailored for different algorithmic approaches. A range of 1 <= x <= 8 goes nicely with brute force, whereas 1 <= x <= 30, goes nicely with the mysterious solution that will not be named. |
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| Author: | Fusha [ Wed Feb 27, 2008 8:08 pm ] |
| Post subject: | Re: RE:Ccc 2008 |
Sane @ Wed Feb 27, 2008 7:13 pm wrote: Hi guys.
I'm a high school student from Ottawa. I signed up for this forum because it appears to discuss computer science competitions and algorithms-- two things I love to study. I'm looking forward to talking to many of you. I finished the senior competition in 90 minutes. Question #4 was the hardest by far. The rest were good. But I think 2008 might have been the easiest year so far, next to 2007 and maybe 1996. So I spent the last 90 minutes of the competition checking and rechecking and checking it again. And now I'm so bloody anxious to get it marked. Haha. I'll give the solutions for 2008 when we get the go ahead from the other schools. The last question (S5/J5) was a duplicate of a previous stage 2 question. I'm not sure if I should disclose any more information, since that might be going too far. Oh: And by the way, the reason they used #5 for both junior and senior is because the input restriction is specifically tailored for different algorithmic approaches. A range of 1 <= x <= 8 goes nicely with brute force, whereas 1 <= x <= 30, goes nicely with the mysterious solution that will not be named. How would you define brute force? A script that lists all the possible combinations and tries them, or something? Sorry, I'm not used to all these programming terms, I just script whatever comes to mind, and usually works |
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| Author: | stde [ Wed Feb 27, 2008 8:11 pm ] |
| Post subject: | RE:Ccc 2008 |
Hi Sane Im just wondering how long did it take u to do s4? and ya once all the schools are done. it would be so nice for you to post the solutions  |
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| Author: | Sane [ Wed Feb 27, 2008 8:12 pm ] |
| Post subject: | RE:Ccc 2008 |
It's not always the case, but in simplest terms, brute force is branching to every possibility. An analogy could be drawn to the recursive formula for the fibonacci sequence. Using the recursive formula for fib(100) will never finish, but other methods can be used to calculate it in polynomial time. Brute force is probably the way that most people tried. But as soon as your numbers get up to 30, code that tries every combination will obviously not finish. However, for 8, it will suffice. Edit: Number 4 took me the longest of all the questions. About 30 minutes. |
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| Author: | technograff [ Wed Feb 27, 2008 8:29 pm ] |
| Post subject: | RE:Ccc 2008 |
Hi, guys, first post on the forum for me as well. Anyhow, I just wrote the contest, and it made me realize how awful I am at programming  . I got S1 done really fast, but I made it in a really inefficient fashion (ugh, don't even go there) so it didn't work for the higher test cases.
I did S2 without much trouble, but once the input cases got high my program crashed. I would LOVE to see a nice and efficient solution to this. Past that, I got bit and pieces of code here and there, but nothing exciting. I hope to absorb some programming prowess from here, so I hope replies get posted soon. Out of curiosity: what languages did people use for this, and were they taught that language in school, or did they learn it as a hobby? |
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| Author: | OneOffDriveByPoster [ Wed Feb 27, 2008 8:29 pm ] |
| Post subject: | Re: Ccc 2008 |
Since the problem set has been posted on the MMHS page... |
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| Author: | Sane [ Wed Feb 27, 2008 8:33 pm ] |
| Post subject: | RE:Ccc 2008 |
I used C, as having learned it in school, and as a hobby. By the way, I see you guys are familiar with the MMHS page. For sake of association, I'm "Aaron Voelker" from the list of credits, and also the mantainer of a similar site, http://codersblock.net/ccc/. |
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| Author: | A.J [ Wed Feb 27, 2008 8:57 pm ] |
| Post subject: | Re: Ccc 2008 |
Senior was easier than I expected this year! I got all 5, but I think my #4 is a bit flawed, but everything else should have been quite easy. I wanted to know how other people did, so that I could make out the cuttoff for Stage 2. Thx |
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| Author: | fantasy [ Wed Feb 27, 2008 9:03 pm ] |
| Post subject: | Re: Ccc 2008 |
gah now i feel bad...i thought i did pretty good...but u guys made it seem so eazy but if all the potential stage2ers did dwite...i should be ok i guess  |
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| Author: | Fusha [ Wed Feb 27, 2008 9:09 pm ] |
| Post subject: | RE:Ccc 2008 |
I wrote the contest in C. Everyone else in my school wrote it in java
I take it that we are allowed to post solutions to our problems now? |
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| Author: | DanielG [ Wed Feb 27, 2008 9:15 pm ] |
| Post subject: | RE:Ccc 2008 |
I finished all 5, but my #4 had a flaw, rare but is probably in one of the test cases. and I made a stupid mistake on #3 by calling my array 0 .. 20, 0 .. 20 instead of 0 .. 21, 0 .. 21 (which is a must for my method of using an outer wall layer. I think I got 1,2, and 5 perfect though. |
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| Author: | Cinjection [ Wed Feb 27, 2008 9:40 pm ] |
| Post subject: | Re: Ccc 2008 |
I completed S1 and S2 easily and quickly and I think that they are pretty solid solutions. I essentially spent the rest of the time doing S3. I managed to get a working solution, but I know that it has a pretty large flaw in it so I know that I will not get the best mark on that particular problem. I think that S4 and S5 were out of my league anyway. |
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| Author: | Sane [ Wed Feb 27, 2008 9:44 pm ] |
| Post subject: | RE:Ccc 2008 |
I just marked my solutions off the test files from MMHS. 74/75 I messed up something stupid too. Anyone beat me?  |
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| Author: | CodeMonkey2000 [ Wed Feb 27, 2008 9:45 pm ] |
| Post subject: | RE:Ccc 2008 |
How are we suppose to do s4? |
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| Author: | stde [ Wed Feb 27, 2008 9:49 pm ] |
| Post subject: | RE:Ccc 2008 |
it seems many people got stuck on s4 uhm.... |
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| Author: | StealthArcher [ Wed Feb 27, 2008 10:09 pm ] |
| Post subject: | RE:Ccc 2008 |
I was the only one in my school to take the senior, I wrote in C++. Seeing as I only learned little of the lang. beforehand, most of my stuff contentiously crashed, and wouldnt work. I scored a miserable 15. |
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| Author: | A.J [ Wed Feb 27, 2008 10:10 pm ] |
| Post subject: | Re: Ccc 2008 |
try all different possibilities of arithmetic symbols and groupings for all permutations of the four numbers. I'll post my code soon, just to be on the safe side  |
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| Author: | Sane [ Wed Feb 27, 2008 10:18 pm ] |
| Post subject: | Re: Ccc 2008 |
A.J @ Wed Feb 27, 2008 10:10 pm wrote: try all different possibilities of arithmetic symbols and groupings for all permutations of the four numbers.
I'll post my code soon, just to be on the safe side Yes, that is correct. But I also noticed the test data doesn't penalize you if you can't handle combinations such as a / (b + c) * d. Maybe those permutations are made negligible for the game of 24. I am not that strong in math. I'm just assuming we can talk about it now, since the test data and problem statements are all up on MMHS. Here's my number 5. For those interested. I'll leave it uncommented intentionally. [mod edit]removed as requested[/mod edit] |
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| Author: | r691175002 [ Wed Feb 27, 2008 10:34 pm ] |
| Post subject: | Re: Ccc 2008 |
IMO S4 was one of the easiest. Just doing: 3^4 * 4! = ~2000 Shows that the problem is easily brute forcible. Is the test data from HHCS correct? S4 Test 1 states that: 1 1 1 10 Should be 22. My program outputs 21 which makes sense to me: (1+1)*10 + 1 How was the 22 derived? I brute forced and successfully completed all other test cases. |
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| Author: | Sane [ Wed Feb 27, 2008 10:37 pm ] |
| Post subject: | RE:Ccc 2008 |
Your algorithm is not correct. (10+1)*(1+1) = 22 |
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| Author: | DiscovererofGUT [ Wed Feb 27, 2008 10:43 pm ] |
| Post subject: | Re: Ccc 2008 |
I did junior, but senior would have been well within my reach. However, I did spend the most time on J4. I thought that J4 was an unreasonable question to put on junior. Also, for S4, if you're using C++, next_permutation would have been useful. http://cplusplus.com/reference/algorithm/next_permutation.html The senior paper was a joke (especially S5 - if you coded J5, you only need to know an easy little trick to make it doable for S5). There was no separator question, one that separates the truly good coders from the bad ones. We have four perfects from our school. |
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| Author: | Sane [ Wed Feb 27, 2008 10:48 pm ] |
| Post subject: | RE:Ccc 2008 |
You had 4 perfects in senior? Really? Yikes! The junior was difficult. I agree. #4 was tricky. |
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| Author: | DiscovererofGUT [ Wed Feb 27, 2008 10:49 pm ] |
| Post subject: | Re: Ccc 2008 |
If you coded in C++, did you use that function I specified in my previous post? And what school do you come from? What did you think of the senior paper? Too easy? By the way, you spelt Rolland wrong in your code. Technically, you should have lost more than just one mark overall. |
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| Author: | Sane [ Wed Feb 27, 2008 11:03 pm ] |
| Post subject: | RE:Ccc 2008 |
Oops, I was just messing with it when I was erasing my comments and crunching lines together. I wonder if when I rewrote that line if I misspelled it, or if I had originally misspelled it too... |
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| Author: | whlue [ Wed Feb 27, 2008 11:04 pm ] |
| Post subject: | Re: RE:Ccc 2008 |
whlue @ Wed Feb 27, 2008 6:45 pm wrote: I got S1-S3 done pretty quickly, S4 threw me off for a while, after trying to figure out a ton of stuff about it which was wrong after an hour of pondering, but I figured out an answer for S4 which was blatantly obvious and only took me 10 minutes to write, and test. Unfortunately, I didn't get a chance to do S5 because of the hour or so wasted from pondering over S4.
So after looking at the test cases on the website, it looks like I actually did screw up S4. This is pretty depressing, but hopefully I'll get over it. I was hoping to get at least S1 to S4 correct. After pondering for a bit, the solution to S5 seems blatantly obvious. @Sane: How do you know the marking scheme for the contest? What marks are each section out of? |
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| Author: | Sane [ Wed Feb 27, 2008 11:08 pm ] |
| Post subject: | RE:Ccc 2008 |
Each question is worth 15. I'm not sure how it's partitioned between each data file, but I messed up one number in a data file in the 3rd question, so I assume that's one mark at most. |
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| Author: | zylum [ Wed Feb 27, 2008 11:44 pm ] |
| Post subject: | RE:Ccc 2008 |
I have to agree with DiscovererofGUT.. This has got to be one of the easiest CCC problem sets I have seen |
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| Author: | Fusha [ Thu Feb 28, 2008 12:06 am ] |
| Post subject: | RE:Ccc 2008 |
Can someone post how one would mark their own test? How much is each test worth, etc. Thanks |
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| Author: | OneOffDriveByPoster [ Thu Feb 28, 2008 12:29 am ] |
| Post subject: | Re: Ccc 2008 |
Sane @ Wed Feb 27, 2008 10:18 pm wrote: Here's my number 5. For those interested. I'll leave it uncommented intentionally. I fail to see the reason why people avoid multiple returns, breaks and continues... |
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| Author: | r691175002 [ Thu Feb 28, 2008 1:12 am ] |
| Post subject: | Re: Ccc 2008 |
After testing my programs myself I failed 1 of S4s test cases and all of S5s test cases (Seeing as I didn't do it). So unless I severely messed up the marking my score will be around 57. Easy or not, I am pretty happy with that. I am not sure if compsci.ca provides a true representation of the difficulty of the test. IMO The test was harder than 2007 if you did not prepare for it, and easier than 2007 if you did. 2007 S3 could have been completed without any knowledge of graph searching, while this year S3 would have been extremely difficult if you had never seen similar problems before. |
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| Author: | klopyrev [ Thu Feb 28, 2008 2:48 am ] |
| Post subject: | Re: Ccc 2008 |
Has anyone figured out yet that the algorithm you need to solve S4 is described in J4? I find that somewhat odd. My first instinct for S4 was RPN. I coded a solution in a couple of minutes and then afterwards, I saw that J4 described RPN. Very odd. I thought this was an interesting contest, but somewhat easy. All the problems are well known. |
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| Author: | klopyrev [ Thu Feb 28, 2008 2:53 am ] |
| Post subject: | Re: Ccc 2008 |
By well known, I mean that you have an advantage if you've done a lot of problems. |
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| Author: | zylum [ Thu Feb 28, 2008 5:58 am ] |
| Post subject: | Re: Ccc 2008 |
klopyrev @ Thu Feb 28, 2008 3:48 am wrote: Has anyone figured out yet that the algorithm you need to solve S4 is described in J4? I find that somewhat odd. My first instinct for S4 was RPN. I coded a solution in a couple of minutes and then afterwards, I saw that J4 described RPN. Very odd.
 I was thinking the same thing! |
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| Author: | aramadia [ Thu Feb 28, 2008 8:59 am ] |
| Post subject: | RE:Ccc 2008 |
Funny thing is that I got s3.3 wrong because I forgot to check if the bottom right corner was occupied. I was debating whether to implement a special case but I thought that the CCC makers wouldn't be that mean. I was wrong... again. Assuming that it was only worth 1 mark, I should get 74/75. |
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| Author: | OneOffDriveByPoster [ Thu Feb 28, 2008 9:26 am ] |
| Post subject: | Re: RE:Ccc 2008 |
aramadia @ Thu Feb 28, 2008 8:59 am wrote: but I thought that the CCC makers wouldn't be that mean Seriously, expect all cases. But they seem to skip cases that most people get wrong... there's at least 3 buggy solutions on the MMHS page (if I was not mistaken and if I remember correctly). |
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| Author: | Sane [ Thu Feb 28, 2008 10:43 am ] |
| Post subject: | Re: RE:Ccc 2008 |
OneOffDriveByPoster @ Thu Feb 28, 2008 9:26 am wrote: Seriously, expect all cases. But they seem to skip cases that most people get wrong... there's at least 3 buggy solutions on the MMHS page (if I was not mistaken and if I remember correctly).
Buggy solutions? Or buggy test files? |
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| Author: | OneOffDriveByPoster [ Thu Feb 28, 2008 10:57 am ] |
| Post subject: | Re: RE:Ccc 2008 |
Sane @ Thu Feb 28, 2008 10:43 am wrote: Buggy solutions? Or buggy files? Buggy solutions, but then Mr. Robart told me that if the solutions work on the test files just fine, then it is the test files that are at fault for being unable to find the bugs.  |
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| Author: | Sane [ Thu Feb 28, 2008 4:30 pm ] |
| Post subject: | RE:Ccc 2008 |
It seems that this year, the number of high scorers will be much higher, but the mean is still lower. Probably because as klopyrev was getting at: S4 was tough, and so was S5, but both were variants of common problems in computer science. So anyone who's a big compsci nerd will have scored high. However, most other people will have only got S1-S3, bringing down the average. It is still strange how only one person got perfect last year (was it our resident klopyrev?)... Because I swear last year's contest was way way easier, especially since there were no tricky questions (all could be solved open-endedly), except for S5. But even then, S5 was just a standard 2D DP problem. So why the sudden increase in perfects this year? Is the test data not tricky enough? Man... I sure hope I don't miss the cutoff for stage 2. It would be a royal bite in the ass if a 74 didn't make it... and that almost seems possible if it took one school to nail 4 perfects. That's ridiculous. |
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| Author: | technograff [ Thu Feb 28, 2008 4:52 pm ] |
| Post subject: | Re: Ccc 2008 |
Actually, the test sheet clearly said that part marks will not be given, so, if one of the test cases is not perfect, 0 will be given. Questions 4-5 have 5 test cases, each one worth 3, so I assume that a score of 74 is impossible and one mistake causes a score of 72, or am I wrong? |
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| Author: | OneOffDriveByPoster [ Thu Feb 28, 2008 5:26 pm ] |
| Post subject: | Re: Ccc 2008 |
DiscovererofGUT @ Wed Feb 27, 2008 10:43 pm wrote: Also, for S4, if you're using C++, next_permutation would have been useful. Used that. |
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| Author: | Clayton [ Thu Feb 28, 2008 6:16 pm ] |
| Post subject: | Re: Ccc 2008 |
technograff @ Thu Feb 28, 2008 4:52 pm wrote: Actually, the test sheet clearly said that part marks will not be given, so, if one of the test cases is not perfect, 0 will be given. Questions 4-5 have 5 test cases, each one worth 3, so I assume that a score of 74 is impossible and one mistake causes a score of 72, or am I wrong?
You are correct. |
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| Author: | Sane [ Thu Feb 28, 2008 6:18 pm ] |
| Post subject: | RE:Ccc 2008 |
Well that's a bummer. Heh. I'll just wait for my official mark then. |
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| Author: | r691175002 [ Thu Feb 28, 2008 6:32 pm ] |
| Post subject: | RE:Ccc 2008 |
Hey, just for comparison, how many times have you all done the CCC before? Are these perfects from first tries or do you have some experience? |
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| Author: | DiscovererofGUT [ Thu Feb 28, 2008 10:01 pm ] |
| Post subject: | Re: RE:Ccc 2008 |
Sane @ Thu Feb 28, 2008 4:30 pm wrote: It seems that this year, the number of high scorers will be much higher, but the mean is still lower. Probably because as klopyrev was getting at: S4 was tough, and so was S5, but both were variants of common problems in computer science. So anyone who's a big compsci nerd will have scored high. However, most other people will have only got S1-S3, bringing down the average.
It is still strange how only one person got perfect last year (was it our resident klopyrev?)... Because I swear last year's contest was way way easier, especially since there were no tricky questions (all could be solved open-endedly), except for S5. But even then, S5 was just a standard 2D DP problem. So why the sudden increase in perfects this year? Is the test data not tricky enough? Man... I sure hope I don't miss the cutoff for stage 2. It would be a royal bite in the ass if a 74 didn't make it... and that almost seems possible if it took one school to nail 4 perfects. That's ridiculous. No last year, someone from Woburn CI got perfect (he did so this year). The last two problems on this year's contest, as you have said, Sane, were simply variants of problems in computer science. You can assume that at least 20 people across Canada were ingenious enough to come up with ways to solve them. Sorry, Sane, but I do believe that at least 20 people across Canada did in fact get perfect. As for most people getting S3, I don't know - how many schools teach BFS in high school? |
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| Author: | DiscovererofGUT [ Thu Feb 28, 2008 10:02 pm ] |
| Post subject: | Re: RE:Ccc 2008 |
r691175002 @ Thu Feb 28, 2008 6:32 pm wrote: Hey, just for comparison, how many times have you all done the CCC before? Are these perfects from first tries or do you have some experience?
Well, of course, you need to have programmed before you can get perfect on any computer science contest. However, unlike SAT scores, the more times you do the CCC, your score should rise (more experience and practice). |
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| Author: | Sane [ Thu Feb 28, 2008 10:06 pm ] |
| Post subject: | RE:Ccc 2008 |
How the heck would 1 person get perfect in 2007, and 20 get perfect in 2008 though? No matter which way I look at it, I can't see 2008 being that much easier. If anything, It was slightly harder. |
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| Author: | DiscovererofGUT [ Thu Feb 28, 2008 10:09 pm ] |
| Post subject: | Re: Ccc 2008 |
Well, that's not true. 2008 was easier. The person we are talking (the perfect person) spent 1 hr 20 minutes doing the senior package. I don't remember how long it took him last year, but it was definitely longer. |
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| Author: | Sane [ Thu Feb 28, 2008 10:22 pm ] |
| Post subject: | RE:Ccc 2008 |
Maybe Graph Theory is just my forte, but last year took me that long to get perfect on. But that was in my own time, because our school never participated... |
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| Author: | klopyrev [ Thu Feb 28, 2008 11:30 pm ] |
| Post subject: | Re: Ccc 2008 |
Well. To show how easy the problem set is. I believe a lot of people could have finished it in an hour. I personally can do every one of the problems in less than 6 or 7 minutes. I know a few people who are currently in high school in Canada who can do that. There will be a lot of perfects. Probably not 20, but still a lot. |
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| Author: | DiscovererofGUT [ Thu Feb 28, 2008 11:48 pm ] |
| Post subject: | Re: RE:Ccc 2008 |
Sane @ Thu Feb 28, 2008 10:22 pm wrote: Maybe Graph Theory is just my forte, but last year took me that long to get perfect on. But that was in my own time, because our school never participated...
You got perfect last year? I'm assuming it was Junior? |
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| Author: | Sane [ Fri Feb 29, 2008 1:10 am ] |
| Post subject: | RE:Ccc 2008 |
No no. Senior. But again, in my own time. Unfortunately. |
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| Author: | nike52 [ Fri Feb 29, 2008 6:10 pm ] |
| Post subject: | Re: Ccc 2008 |
Hey. Since you guys are so really really awesome. ALL HAIL. Can you guys give us some tips for newbies starting out ?
I will wuv you. |
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| Author: | stde [ Sat Mar 01, 2008 4:09 pm ] |
| Post subject: | RE:Ccc 2008 |
for this years senior problem, its either you know it or you dont. if you know dp, then none of the problems would be difficult...in general. I still think s4 is the hardest of all? Sane, I have printed the book out and binded into a book. I want to thank you again for sharing it. : ) |
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| Author: | CodeMonkey2000 [ Sat Mar 01, 2008 9:52 pm ] |
| Post subject: | RE:Ccc 2008 |
For those interested, topcoder is a great place to learn and compete in algorithmic type problems. They start off easier and you get to view other people's code. It's worth a look. |
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| Author: | Cinjection [ Sun Mar 02, 2008 11:47 am ] |
| Post subject: | Re: Ccc 2008 |
I think that the Senior for 2008 was considerably harder this year than last year. In 2007, I got 4 out of 5 problems. Only problem 4 required an advanced technique, like dynamic programming. This year, I couldn't even get perfect on problem three, because I didn't know enough about graph theory. I got 36 this year, but if I wrote the 2007 one, I'm confident that I could've broken the 50 mark. |
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| Author: | McKenzie [ Sun Mar 02, 2008 4:58 pm ] |
| Post subject: | Re: RE:Ccc 2008 |
DiscovererofGUT @ Thu Feb 28, 2008 10:01 pm wrote: Sorry, Sane, but I do believe that at least 20 people across Canada did in fact get perfect. As for most people getting S3, I don't know - how many schools teach BFS in high school?
I strongly disagree. Sane, if you only had one test case wrong you probably have a 72. I firmly believe that 72 will go to stage 2. The whole "across Canada" thing is a bit of a red herring. There are far more than 20 kids across Canada that are smart enough to learn what it takes to get perfect, but there are far less than 20 kids who have learned what it takes. It's not because some schools teach the concepts and other ones don't. It's because some schools have fostered an environment that supports excellence in Computer Science, and most schools don't. There are only a handful of schools that have a culture that makes it desirable for kids to spend a great deal of their free time training in Computer Science. So, Woburn has 4 perfects. Woburn has the most aggressive CS enrichment in the country. You can use their results as your benchmark. The cut-off is not going to be 75, it will probably be mid-60s. |
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| Author: | nike52 [ Sun Mar 02, 2008 5:30 pm ] |
| Post subject: | Re: Ccc 2008 |
Sane is going to stage 2. That's insane ! |
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| Author: | CodeMonkey2000 [ Sun Mar 02, 2008 9:40 pm ] |
| Post subject: | RE:Ccc 2008 |
I thought he did it on his own time, and thus is illegible. |
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| Author: | Sane [ Mon Mar 03, 2008 3:08 pm ] |
| Post subject: | RE:Ccc 2008 |
@stde: I'm happy to hear you're making use of my secret weapon.
Edit: For those interested, this is the book I recommended to stde. http://www.cs.berkeley.edu/~vazirani/algorithms.html It was my only resource from which I learned all I needed, from nothing, for the CCC. But it required at least 100 hours of reading, studying and coding... @Cinjection: I agree. Last year, you could have even brute forced #4 (allowed repeated subproblems), and still get all the test files within 5-6 seconds. My initial reaction with this year's difficulty was understated. It's harder, but only because you would have needed to know about #3 and #5 in advance, and #4 you just have to be fast. @McKenzie: Thank-you for your response. It's very reassuring to know that Woburn shouldn't be considered the normal. I was under the impression, given by a couple posters, that 75 would be the cutoff, but you seem to know much more about this, so I'll trust you on it. If one wrong test file for #3 is 72, that's probably what I've ended up with then. I'm excited. Now I just need my teacher to make the official mark already! =X @nike52: Thanks. I hope so! I spent a lot of time studying for this contest. The last few months have been the longest of my life. @CodeMonkey: I was talking about 2007 being the one I did in my own time, in preparation for 2008. |
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| Author: | bleungpwns [ Tue Mar 04, 2008 1:24 pm ] |
| Post subject: | Re: Ccc 2008 |
DiscovererofGUT @ Wed Feb 27, 2008 10:43 pm wrote: I did junior, but senior would have been well within my reach.
Those are some big words for someone who ended up getting .. 48/75 on the junior section. As for 20 perfects in Canada, you obviously have no idea what you are talking about. Cutoff will probably be mid-high sixties. It seems that your ego is inversely proportional to your knowledge. |
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| Author: | Sane [ Tue Mar 04, 2008 1:41 pm ] |
| Post subject: | RE:Ccc 2008 |
Snap. It suddenly makes sense.
I take it you're from his school, bleungpwns? How'd you do? I take it went fairly well? |
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| Author: | bleungpwns [ Tue Mar 04, 2008 2:03 pm ] |
| Post subject: | Re: Ccc 2008 |
Well, a bunch of us felt irritated about DiscoverofGUT's behavior and so posted this message. You will meet us at stage 2(hopefully ). |
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| Author: | Sane [ Tue Mar 04, 2008 4:23 pm ] |
| Post subject: | RE:Ccc 2008 |
Looking forward to meeting you guys. I'm sure I'll learn a lot from the experience. |
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| Author: | DanielG [ Tue Mar 04, 2008 7:16 pm ] |
| Post subject: | RE:Ccc 2008 |
I got 58/75, I messed up 2,3 and 4 (losing about 6 points on each). So I probably won't make stage 2. |
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| Author: | CodeMonkey2000 [ Tue Mar 04, 2008 10:23 pm ] |
| Post subject: | Re: Ccc 2008 |
klopyrev @ Thu Feb 28, 2008 11:30 pm wrote: Well. To show how easy the problem set is. I believe a lot of people could have finished it in an hour. I personally can do every one of the problems in less than 6 or 7 minutes. I know a few people who are currently in high school in Canada who can do that. There will be a lot of perfects. Probably not 20, but still a lot.
Sounds like you are IOI worthy. Did you ever make it to IOI? If so, how did you practise/prepare. |
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| Author: | richcash [ Wed Mar 05, 2008 6:42 pm ] |
| Post subject: | RE:Ccc 2008 |
Well, this answers your first question. |
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| Author: | CodeMonkey2000 [ Wed Mar 05, 2008 10:59 pm ] |
| Post subject: | RE:Ccc 2008 |
0_o holy crap. |
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| Author: | StealthArcher [ Wed Mar 05, 2008 11:00 pm ] |
| Post subject: | RE:Ccc 2008 |
Did you get your four golds? |
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| Author: | klopyrev [ Thu Mar 06, 2008 6:03 pm ] |
| Post subject: | Re: Ccc 2008 |
No, we didn't get four golds. My gold slipped away from me, because I didn't test my solutions. Boy, was I mad when I found out that I got 75 points on the first day, when I was expecting over 200. After minor fixes on my solutions, I got over 200 points, but that was after the contest. Lesson is: TEST YOUR SOLUTIONS. |
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| Author: | Sane [ Thu Mar 06, 2008 6:29 pm ] |
| Post subject: | RE:Ccc 2008 |
Hey klopy. That was in 2007's stage 2, correct? I've been trying for some time to get the right results for the Cows problem. My output files are slightly off. But strangely enough, another convex hull algorithm I found online creates the same convex hull that my algorithm creates for the test files I get incorrect. So either I misunderstand the question, or both algorithms are slightly incorrect. I'm also not sure how much I should trust the files, because the last output file for Bowling for Numbers++ is riddled with plaintext error messages. Furthermore, the Gerrymandering question from day 2 says "I don't know!" all throughout the final output files... Mind if we chat on MSN or anything? drsane_@hotmail.com? |
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| Author: | Zampano [ Thu Mar 06, 2008 7:47 pm ] |
| Post subject: | Re: Ccc 2008 |
57, Junior. |
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| Author: | klopyrev [ Thu Mar 06, 2008 8:26 pm ] |
| Post subject: | Re: Ccc 2008 |
No, that was IOI 2007. |
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| Author: | A.J [ Fri Mar 07, 2008 12:18 pm ] |
| Post subject: | Re: Ccc 2008 |
hey klopyrev! looks like our #5 solution for the CCC made the unofficial solutions! Nice! But many of your solutions have got posted before, and u beat me to the BFS solution for #3 (since u sent it to chris faster than me, and yours was easier-to-understand compared to my BFS procedure) Oh well, at least I know that an IOI guy beat me  |
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| Author: | FindingPi [ Fri Mar 07, 2008 4:40 pm ] |
| Post subject: | Re: Ccc 2008 |
Just wondering, are the files in mmhs the actual test files. For S5, when i read in using BufferedReader in = new BufferedReader (new FileReader ("s5.in")); and in.readline i get blank lines between each line which crashes my program... Looking at it through notepad, everything looks normal, but with another text editor, i also see blanks between each input line. |
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| Author: | A.J [ Fri Mar 07, 2008 5:23 pm ] |
| Post subject: | Re: Ccc 2008 |
the blanks are supposed to be there, so u have to tweak your program so that it works. And yes, all the test files there are the official. |
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| Author: | FindingPi [ Fri Mar 07, 2008 6:41 pm ] |
| Post subject: | Re: Ccc 2008 |
A.J @ Fri Mar 07, 2008 5:23 pm wrote: the blanks are supposed to be there, so u have to tweak your program so that it works.
And yes, all the test files there are the official. hmm.... So do i get zero if i didn't account for the blanks? There is no mention of blanks in the problem. |
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| Author: | A.J [ Fri Mar 07, 2008 9:01 pm ] |
| Post subject: | Re: Ccc 2008 |
if you are asking if any of the answers to the test files are 0's, its a no. Post your code and I'll help u out. But before u do that, make sure u DID take the spaces into account (include it in your code) sry if I am not making any sense to u (I seem to have that effect on people ) |
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| Author: | Sane [ Fri Mar 07, 2008 10:11 pm ] |
| Post subject: | RE:Ccc 2008 |
FindingPi was asking if he gets 0/75 because he didn't handle the additional blank lines. Consequently, none of the test files work. |
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| Author: | A.J [ Fri Mar 07, 2008 10:19 pm ] |
| Post subject: | Re: Ccc 2008 |
Oh, in that case FindingPi, dont worry !
I didn't deal with the blanks and I got #4! So relax, u probably did well! |
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| Author: | Sane [ Thu Mar 27, 2008 6:56 pm ] |
| Post subject: | RE:Ccc 2008 |
Does anyone know when we should be expecting the competition results? The end of march right? But I don't see anything on cemc.uwaterloo.ca/ccc/ yet. |
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| Author: | A.J [ Thu Mar 27, 2008 11:07 pm ] |
| Post subject: | Re: Ccc 2008 |
the list of who mad stage 2 will mostly come out by April 2nd |
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| Author: | Sane [ Thu Mar 27, 2008 11:09 pm ] |
| Post subject: | RE:Ccc 2008 |
Okay. Thanks. |
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| Author: | Sane [ Wed Apr 02, 2008 10:36 am ] |
| Post subject: | RE:Ccc 2008 |
Still waiting on the results!  |
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| Author: | Sane [ Wed Apr 02, 2008 11:37 pm ] |
| Post subject: | RE:Ccc 2008 |
Yes! The results are a day late, but they're in. http://cemc.uwaterloo.ca/ccc/2008/2008.result.pdf Good game. Who else from compsci's in? |
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| Author: | zylum [ Wed Apr 02, 2008 11:47 pm ] |
| Post subject: | RE:Ccc 2008 |
Wow a 66 to get to stage 2.. I haven't checked but isn't that the highest cutoff ever? Usually its in the 50s no? |
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| Author: | Sane [ Wed Apr 02, 2008 11:54 pm ] |
| Post subject: | RE:Ccc 2008 |
Yeah. Troy says on the second page that this is definitely a higher average than normal. I also read in an e-mail that he had a difficult time picking the top 20. You will notice about 24 people were invited this year which is also unusual. |
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| Author: | McKenzie [ Thu Apr 10, 2008 9:17 pm ] |
| Post subject: | Re: Ccc 2008 |
Sane, I expected to see you on the invite list for stage 2, what happened? |
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| Author: | sven87 [ Sat Apr 12, 2008 5:35 pm ] |
| Post subject: | Re: Ccc 2008 |
but he IS on there |
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| Author: | A.J [ Sat Apr 12, 2008 5:58 pm ] |
| Post subject: | Re: Ccc 2008 |
Sane is Aaron Voelkor..if I'm not wrong |
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| Author: | McKenzie [ Sat Apr 12, 2008 7:01 pm ] |
| Post subject: | Re: Ccc 2008 |
That's cool, congrats. I didn't see anyone from Ottawa in the Stage 2. So Nepean is close to Ottawa, I quess. |
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| Author: | Sane [ Mon Apr 14, 2008 11:52 am ] |
| Post subject: | RE:Ccc 2008 |
Yeah. Neapean is in Ottawa. I ended up with 75/75 (I was quite surprised), since what I thought was a mistake, was not after all. So I just got the form to claim the prize from the school today. Yay.
Preparing hardcore for stage 2 now. This will be really tough. Best of luck to ya Steven. Anyone know the names of the other 6 perfects? I'm a little frightened to say the least. |
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| Author: | sven87 [ Tue Apr 15, 2008 6:30 pm ] |
| Post subject: | RE:Ccc 2008 |
the other fiive perfects :O |
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| Author: | mwplachta [ Sat Apr 19, 2008 8:56 pm ] |
| Post subject: | Re: Ccc 2008 |
I see a total of 7 perfects in the CCC stage 1. |
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| Author: | mwplachta [ Sat Apr 19, 2008 10:07 pm ] |
| Post subject: | RE:Ccc 2008 |
It is still strange how only one person got perfect last year (was it our resident klopyrev?)... Last year's perfect was Hanson's from Woburn. |
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| Author: | mwplachta [ Sat Apr 19, 2008 10:10 pm ] |
| Post subject: | Re: Ccc 2008 |
bleungpwns @ Tue Mar 04, 2008 1:24 pm wrote: DiscovererofGUT @ Wed Feb 27, 2008 10:43 pm wrote: I did junior, but senior would have been well within my reach.
Those are some big words for someone who ended up getting .. 48/75 on the junior section. As for 20 perfects in Canada, you obviously have no idea what you are talking about. Cutoff will probably be mid-high sixties. It seems that your ego is inversely proportional to your knowledge. Actually his score was 45 not 48 - even lower. |
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| Author: | Sane [ Fri May 23, 2008 2:17 pm ] |
| Post subject: | RE:Ccc 2008 |
I'm heading down to Waterloo now. Staying with family until Monday. Best of luck to all who will be there. See ya guys soon. |
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| Author: | sven87 [ Fri May 30, 2008 10:40 pm ] |
| Post subject: | RE:Ccc 2008 |
sane wins everything forever. if i had..8 more points i would have gotten gold. and i got 17/25 on problem 1 day 1 somehow. i'm so mad at myself. |
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| Author: | Sane [ Fri May 30, 2008 10:50 pm ] |
| Post subject: | RE:Ccc 2008 |
Oh my god Steven... That's actually really depressing. That's so close and it would have been cool to have you on the team... You were really close, and in the end it really doesn't matter. The IOI is just for fun, and the difference in ability between those who make it and those who don't is so minuscule. Let's do well on the UW Local this September. k?
Do you know what your mistake on 1-1 was yet? And congrats again on doing very well. I think everyone who came to Stage 2 was very closely matched. |
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| Author: | sven87 [ Sat May 31, 2008 9:41 am ] |
| Post subject: | RE:Ccc 2008 |
sigh, well, a lot of it came down to who made the fewest little mistakes. if i hadn't messed up question 1, then i would have beat robin by 1 point and he'd be saying the same thing..i imagine brian bi feels worse, he was only 6 points away and got 4/25 on problem 4. |
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| Author: | Sane [ Sat May 31, 2008 4:43 pm ] |
| Post subject: | RE:Ccc 2008 |
Wow. Yeah, see that's what I mean. It hurts for everyone. It sucks how Troy can only take 4, because many people were definitely deserving. Where are you getting these scores from anyways? Send me the link on MSN or something. |
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| Author: | bugzpodder [ Sun Jun 01, 2008 1:51 pm ] |
| Post subject: | RE:Ccc 2008 |
not to poor cold water on your enthusiasm, but this year's waterloo team is pretty much set, klopyrev, malcolm and richard. I'll give you props if you can push one of these guys off. |
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| Author: | bbi5291 [ Sun Jun 01, 2008 5:22 pm ] |
| Post subject: | Re: Ccc 2008 |
Oh yes I do feel bad, especially about the 4/25... and I was really hoping to beat David Zhang's record as youngest Canadian IOI competitor. Even still, keep in mind that Guru didn't win gold either, and he's probably the second best in Canada (next to Hanson). I wonder how he feels? |
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| Author: | Sane [ Sun Jun 01, 2008 6:25 pm ] |
| Post subject: | RE:Ccc 2008 |
bugzpodder? We're not even talking about the ACM? ... :S |
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| Author: | klopyrev [ Mon Jun 02, 2008 12:23 pm ] |
| Post subject: | Re: Ccc 2008 |
You did mention UW Local. That's ACM. |
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| Author: | Sane [ Mon Jun 02, 2008 3:28 pm ] |
| Post subject: | RE:Ccc 2008 |
Yeah, but I meant for fun. That's what these contests are for: Fun. |
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| Author: | klopyrev [ Mon Jun 02, 2008 5:37 pm ] |
| Post subject: | Re: Ccc 2008 |
Yes, they are for fun. However, winning contests and getting to travel the world because of that is very fun.
ACM finals will be held in Stockholm, Sweden next year. I'm somewhat excited to go there. However, one of you guys can steal my spot if you try hard enough. |
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| Author: | bugzpodder [ Fri Jun 13, 2008 11:58 am ] |
| Post subject: | RE:Ccc 2008 |
tell you what, beating klopyrev is fun I managed to beat richard two years ago and that was really fun (and almost beat malcolm, only 5 penalty points short for the black team, doh)
but these guys schooled me last year  |
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| Author: | thegoose [ Sun Jun 15, 2008 4:58 pm ] |
| Post subject: | Re: RE:Ccc 2008 |
bugzpodder @ Fri Jun 13, 2008 12:58 pm wrote: tell you what, beating klopyrev is fun
I managed to beat richard two years ago and that was really fun (and almost beat malcolm, only 5 penalty points short for the black team, doh)
but these guys schooled me last year ....and klopyrev won. http://plg1.cs.uwaterloo.ca/cgi-bin/cgiwrap/acm00/score2.cgi GG |
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| Author: | saltpro15 [ Mon Feb 02, 2009 9:08 pm ] |
| Post subject: | RE:Ccc 2008 |
ha this is a necro but I refuse to start a new topic for the same topic. Did anyone ever get J5 of the 2008 CCC in Turing? I'm doing the 2008 questions as prep. for the 09 CCC and so far I'm 4/4 , any help with the 5th would be great though, thanks |
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| Author: | CodeMonkey2000 [ Mon Feb 02, 2009 10:38 pm ] |
| Post subject: | RE:Ccc 2008 |
I don't have a turing solution, but I know that the problem was a DP. Let [i][j][k][l] be the amount of chemical a,b,c and d you have. If you know that [i][j][k][l] is a loosing spot for Patric, then if Ronald has any reactions that leads to that state, Ronald is the winner, and vise versa. By default you know that [0][0][0][0] is a loosing state for Patrick since he goes first. Infact there are a bunch of loosing states you can deduce. |
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| Author: | DanielG [ Mon Feb 02, 2009 10:44 pm ] |
| Post subject: | RE:Ccc 2008 |
quad for loops, that's how I did senior last year in turing and it worked (I don't have my solution anymore though). You could also try to use memoization, using 4d array again, but using recursion instead of dp to build the table. |
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| Author: | saltpro15 [ Tue Feb 03, 2009 3:31 pm ] |
| Post subject: | RE:Ccc 2008 |
I got it today using DP, and memoization , thanks guys |
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| Author: | chopperdudes [ Tue Feb 03, 2009 6:27 pm ] | ||||
| Post subject: | Re: Ccc 2008 | ||||
hmm saltpro, i would like to see your code in turing, and possibly explain the reason behind your dynamic programming. I've not done more than filling an array with recursion, then looking it up later on during the recursion (ie. fib numbers), but i don't really get how to fill the table of values with just for loops alone. so i would really like to see your solution. I also solved mine in turing, junior i did basic recursion, and senior with direct recursion filling up a 4D array. here's the code: junior:
senior:
anyone thinks my solution for junior is easier to understand than the indirect recursion in the unofficial solution? (and of course in senior the real DP approach should be better i take it.) |
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