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Google Code Jam – Contest scoreboard

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Re: Google Code Jam – Contest scoreboard

#21

Post by dllu »

mjp94 wrote: post #12
dllu wrote: post #7

Earlier quoted context omitted.

Speaking as the current #20 position [0] on the Google Code Jam scoreboard... I'm in my university's team for the ACM ICPC [1]. We practice about one or two times per week, where each practice session is 5 hours. Some of the stronger programmers really practice this stuff every day. cf. Nick Wu's description of his preparation for programming contests [2]. [0] In 5 hours, the large input sets will be judged. I might…

If you don't mind me asking, how do you guys? I always compete in my university's "local" contest, which is basically a tryout for competing for a spot on the team that goes to the ACM. I try doing practice problems, but when I can't solve one, I'm not sure where to go from there.

It just takes a bit of practice. Once you've seen a certain type of problem before, it is easy to identify other problems that can be somehow reduced to a known problem. Speed comes with practice too... soon, basic constructs like for-loops just get etched into muscle memory. Don't worry, I couldn't even solve a single problem in my first tryout at my university.

At my university, after a practice session, we sometimes discuss solutions to problems so that those who couldn't figure them out will know how to solve them in the future. After being told the solution to a problem you couldn't solve, you should try coding it up anyway.

Re: Google Code Jam – Contest scoreboard

#22

Post by pedrosorio »

bouk wrote: post #15
admp wrote: post #9

Earlier quoted context omitted.

There's an interview with Korotkevich dating from IOI 2009: - How many hours a day are you in front of the computer? - Not more than three to four. I like playing football and table tennis, so I try to find time for sports as well. http://www.ioi2009.org/downloads/br8-3str-en.pdf

Three to four hours of practice a day is quite a lot, in comparison Johnny Ho ( http://www.quora.com/TopCoder/Who-is-Johnny-Ho ) only did about 1 or 2 a day while practicing for IOI 2012 Source: me asking that exact question to him at IOI 2012

"Not more than three to four." != "Three or four hours practicing every day consistently"

Also, this guy has been performing at an extremely high level for years. If he didn't do any competitive programming practice at all for a year, I doubt you'd notice a big difference in his performance.

Some of the top guys at Topcoder Open / Google Code Jam don't even participate in matches outside of the yearly tournament and I doubt they are practicing consistently (i.e. once you get to that level at problem solving, performance doesn't seem to decay much and certainly much less than in a similar situation for athletes - though these guys are students / engineers whose brains are still being stimulated and solving other kinds of problems outside of competitions).

Re: Google Code Jam – Contest scoreboard

#23

Post by aviraldg »

Noxchi wrote: post #14

When someone asks why not outsource the coding to India, point them to this page. The first Indian winner is #236, but if you go to the last page, there are a bunch of them trying. EDIT: I'm gonna make a script to list the best countries that output programmers.

There are a lot of people who've only solved a single problem, and the ranking will tend to cluster people from the same timezone together (even if they eventually solve more problems)

Also, competitive programming contests are really popular at Indian schools, so a lot of these could be HS students (nothing to back this up, though - they don't publish this information)

Re: Google Code Jam – Contest scoreboard

#24

Post by pedrosorio »

Noxchi wrote: post #14

When someone asks why not outsource the coding to India, point them to this page. The first Indian winner is #236, but if you go to the last page, there are a bunch of them trying. EDIT: I'm gonna make a script to list the best countries that output programmers.

No need to do that, this website contains statistics for all rounds in the past 6 years: http://www.go-hero.net/jam/13/regions

You'll find the same countries consistently at the top: Russia, Poland, Belarus, Ukraine (i.e. Eastern Europe) and China, Japan (i.e. East Asia) as well as a few others. No news here.

Regarding "but if you go to the last page, there are a bunch of them trying", this is also a function of how many "bad programmers" participate. There's no way to tell whether bad Polish or US programmers filter themselves out of these competitions but Indians not so much.

Re: Google Code Jam – Contest scoreboard

#25

Post by raphaelj »

just2n wrote: post #8

So all evidence suggests that the 3rd problem is the hardest, by far, which is likely just some number of non-obvious edge cases. Curious why the "hard problem" disclaimer is on the 4th? The 4th also has a 90% solve rate (with 50% more submissions) while the 3rd has 44%.

The 4th is definitively the funniest.

In addition to the disclaimer, one thing which worried me was the N <= 1000 in the large problem specification. I got a quite elegant fast solution and a so low bound was really surprising.

Re: Google Code Jam – Contest scoreboard

#26

Post by yeukhon »

modulus1 wrote: post #4

I'm always amazed at the speed of these guys. Top guy got it all done in an hour. I don't know if they are geniuses or if they practice this stuff every day.

Just a thought: I supposed many of them are in fact very smart people. Hours of practice certainly helps a lot as you can break down a complex problem into smaller and familiar problem sets. Some people like Nick Wu probably isn't your average student. Also luck plays a major part. If you just happen to know how to solve problem X you can solve it quickly.

Re: Google Code Jam – Contest scoreboard

#27

Post by RookToH7 »

mjp94 wrote: post #13
RookToH7 wrote: post #11

Earlier quoted context omitted.

Yeah, that disclaimer scared me off at first. I solved D last, but in the end I do feel that it's easier than C. I suppose you can solve C-small with a more naive method though.

Agreed. I definitely found D much easier than C. Was able to get C small after a failed attempt, but never stood a chance at getting C large.

The odd thing is, though, I still don't really see how you can solve C-small without solving C-large at the same time (other than actual brute-force). Guess I'll be keeping my eyes peeled for the write-up.

Re: Google Code Jam – Contest scoreboard

#28

Post by pedrosorio »

prezjordan wrote: post #3

Had a lot of fun with this one. Seems much tougher than previous years.

I disagree. Unlike other years, there is no "hard" problem in this round. So far, 2581 users have submitted an answer to C-large (the "hardest" this year). Last year only 547 users submitted an answer to D-large (and only 141 got the correct answer).

Re: Google Code Jam – Contest scoreboard

#29

Post by pedrosorio »

modulus1 wrote: post #4

I'm always amazed at the speed of these guys. Top guy got it all done in an hour. I don't know if they are geniuses or if they practice this stuff every day.

"I don't know if they are geniuses or if they practice this stuff every day."

It's not an either/or question though =) By most common definitions, the guys at the top, specially those that reach the finals are "geniuses" at algorithmic problem solving, yes.

Re: Google Code Jam – Contest scoreboard

#30

Post by pedrosorio »

RookToH7 wrote: post #27
mjp94 wrote: post #13

Earlier quoted context omitted.

Agreed. I definitely found D much easier than C. Was able to get C small after a failed attempt, but never stood a chance at getting C large.

The odd thing is, though, I still don't really see how you can solve C-small without solving C-large at the same time (other than actual brute-force). Guess I'll be keeping my eyes peeled for the write-up.

"other than actual brute-force"
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