Kattis Problem Archive | Hacker News Reader

Kattis Problem Archive

open.kattis.com

62 pointswamatt17 comments

This is kind of creepy, I registered this morning and started practicing with the trivial exercises, I didn't fill anything special in the registration form besides the username, and now — around six hours later — my profile has been automatically updated with an association to my university and country (which I also didn't select when I signed up). I am not surprised by the country selection, they can easily get that information with a good GeoIP database, but I wonder who did they get the name of my university, maybe from LinkedIn since it is the only place that I am aware of contains that information. Kattis seems like a fun project nonetheless, but these two things scared me out a little bit.

It's not scary in and of itself, they just gave you an awareness of the open source intelligence available on you.

Nice to see this getting attention :)

So here's something rather unusual (or not?): While HN says I submitted this story 6 hours ago, actually I submitted it 2 days ago.

A HN Algolia search confirms

https://hn.algolia.com/?query=kattis or http://imgur.com/a/O0pws

At the time, I was a little surprised to see it not get upvoted more. OTOH it was kind of a slow period (Sunday evening IIRC). The original submission stayed for a few hours, then dropped off the frontpage with only a vote or two.

Which does make one curious, in what way could this occur? Had I bungled a planned HN launch? (and then maybe a mod helped out to resubmit). Or is there some other mechanism at work.

This is a good time to bring up the fact that Advent of Code[1] will be returning this December. I had a blast working through it last year and can't wait for more.

1. http://adventofcode.com/

I really like all the different rank lists that are available.

  https://open.kattis.com/countries/MEX
  https://open.kattis.com/universities/unam.mx
  https://open.kattis.com/ranklist/universities

Nicely done!

On the help section it says I can write my solution on any language. How do I submit my solution in a language not supported by kattis?

"Then you write code to solve the problem in your favourite language (or some other language, if your favourite one is not supported by Kattis)."

Which language did you want to use?

Elixir or Erlang. I'm trying to learn those.

I also hoped that they support Elixir.

I feel stupid for misinterpreting the statement on the help section. Sorry.

Don't... you're definitely not the first to do that :).

Never heard of this. How does it compare to euler or topcoder practice rooms?

On Euler you're asked for the answer, not an implementation solving the problem. This means that you can solve the problem with an implementation that takes days to run or require some manual steps. On Kattis you submit source code to the system, so the runtime limit will be on the order of seconds (definitely not days).

Topcoder has "more interface". With Kattis you would typically code in whatever editor/IDE you have and prefer. Also, Topcoder asks you to implement a function, Kattis asks you to write an entire program. The most important (?) difference being that the latter includes I/O.

Im pretty sure that this is a public version of the platform that has been running at KTH (royal institute of technology) for years. It was used as a test suite as well as performance test for assignments there for the CS school.

That is correct, it went popular when it was used at ACM ICPC world finals some years ago.

And still is. Also, more and more ICPC regional contests have started using Kattis.

There are many problem archives online, each with its own characteristics. Project Euler has math problems where answers are submitted via plaintext, TopCoder has its own flavor of problems with an ancient Java applet interface (although it has a new, still very primitive, web version in beta).

Compared to other problem archives, the Kattis Problem Archive has a very high ratio of quality/quantity. Also, the average problem statement on Kattis is more interesting than the average problem statement on TopCoder/Codeforces (e.g. "Fox Ciel just got this sequence of integers as a birthday present from his grandma, ...".)

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