Announcements (Search)

Delete your own submissions

by bbi5291 on Aug 25, 2009 - 6:37:26 pm UTC
  • (1/0)
You now have the ability to delete your own submissions. There should be a "delete" link next to all of your own submissions. Remember, once a submission is deleted, you no longer receive the points for it. You will receive a popup confirmation dialog asking you if you're sure that you want to delete the submission. After a submission is deleted, the file is still retained on the server, so we may be able to restore your source if you later decide that you were an idiot and you want your code but you don't have it saved locally. Of course, that would be highly annoying and is unlikely to work since it's difficult to identify which file is which.

To admins: You will not receive this annoying popup dialog for two reasons. One: you guys are less likely to accidentally hit "delete" (I hope); two: it makes it easier for you to delete multiple submissions quickly, when the need arises. Also, I have moved "delete" out of the "edit" page.

You can also delete submissions to problems of which you are the author. Remember, we encourage everybody to submit original problems for inclusion in the problemset.

IOI problems are here!

by bbi5291 on Aug 23, 2009 - 2:57:08 am UTC
  • (2/0)
I have begun to add the problems from past IOIs. This will probably be completed sometime within the next week. I am intentionally omitting interactive problems (these are difficult to set up right now; this will hopefully be fixed soon), problems for which I wasn't sure that the "official" solutions were actually optimal, and problems that already appear on the USACO training pages.

I know IOI seems a bit intimidating, but trust me, it is not as impossible as it may seem. Most IOI problems are far from trivial but in earlier years most of you should be able to get significant partial points on most of the problems (with a bit -- or maybe a lot -- of work, of course.)

Now, as these problems are being added in a hurry there wasn't enough time to fully check everything. I did not have time to write solutions to these problems, so I don't know how difficult they are. I will be examining submitted solutions and I may raise or lower the point value, or perhaps check/uncheck the partial score option depending on what seems fair. You can also complain if you think that the value is too low.

So far 11 of the problems have required custom judges (that is, it is not as simple as just checking if your output is the same as the judge output, so a different program is required to grade your output). And there are more to come. I had to write all of these and did not test them extensively. If your program seems to be giving correct output but it is marked wrong, or you think that the score you deserve on a testcase based on the grading info at the bottom of the problem statement is different than the score you got, tell me and I'll fix it. (Note that "judge output" can be misleading; in fact for most of these problems, if your program's output is the same as the "judge output" shown, it will be wrong.) Again, I will be monitoring submissions to try to catch these mistakes.

Finally, if there is something wrong with a problem statement (for example if the sample data was copied incorrectly) then obviously do tell so I can fix it.

Language requests

by bbi5291 on Jul 25, 2009 - 7:25:16 pm UTC
  • (1/0)
Are there languages you guys would like to see added?
(I am in the process of setting up language rules - aplusb2 is too easy in languages that support bignums natively, for example.)

Haskell support

by bbi5291 on Jul 24, 2009 - 4:09:28 am UTC
  • (0/0)
Since I was learning Haskell and decided I needed some problems on which to practice, you now have the option of submitting programs written in Haskell. The compiler is ghc 6.8.2.

I'm having some problems though: on aplusb2 I get SIGVTALRM on the last test case -- Hanson, can you help?

Note on passwords

by bbi5291 on Jul 18, 2009 - 2:04:43 pm UTC
  • (1/0)
Avoid using passwords for the PEG judge that are the same as passwords for other accounts (ideally you should never use the same password for more than one account, but I myself break this rule all the time), because a satisfactory security assessment has not been carried out (so if a hacker gains unauthorized access, say, by SQL injection, he could crack your passwords).

Edit: OK fine, never mind.

Last Bi-weekly Challenge

by SourSpinach on Jun 04, 2009 - 4:29:26 pm UTC
  • (1/0)
The last "bi-weekly challenge" has recently been posted on the judge (consisting of Boxdropper, Union Laser, and Boxlings). The values of these problems will be reduced after the points deadline for grade 11/12 enriched, which I believe is the end of next week.

Though it's hard to solve these problems for full points, it's very easy to get partial marks on each of them, so a stupid solution might even get you more points than you deserve since the problems are currently worth a lot. This applies to most of the bi-weekly challenge problems from before as well, many of which also have hints posted under them, so if you're looking for some last-minute points, try solving some of these problems partially.


by ultblad1 on Apr 29, 2009 - 9:05:00 pm UTC
  • (24/0)
We will miss you, Ms. Plachta.

Mystery Program

by ultblad1 on Apr 20, 2009 - 11:44:07 pm UTC
  • (3/8)
There is a new arrival on the Judge.
Appalled by the lack of faith in your Big Brother, we have decided to roll out new measures to destroy our enemy Jacob.

As much as I would like to, nothing will be revealed about this secret hidden facet of the Judge. All I can say is that it is a secret file, that if discovered, will reward the user with CENSORED.

Be the first to discover this program!

Come one, come all, comrades.

Memory usage accuracy improved

by hansonw1 on Apr 13, 2009 - 11:22:39 pm UTC
  • (8/0)
Thanks to some leet hax, the memory detector is now pretty accurate (It's certainly not perfect, but at least it's consistent 90% of the time)

C++ users will note that the memory usage for an empty program is 2.8MB - this is normal, as the C++ libraries do take up memory. Pascal programs only have about 208KB of overhead, though.

Cleanup of Problem Statements

by hansonw1 on Mar 20, 2009 - 12:33:31 pm UTC
  • (2/0)
As you might notice a lot of the problem statements are either images or badly-copied HTML.
With the former it's quite difficult to copy sample inputs and such; in the latter case it sometimes looks ugly.
Also, it would be much clearer if all references to prompts / files were removed.

I've fixed some of the statements, but there's obviously far too many to clean-up alone. Anyone interested in doing some cleanup work? :)
You'd get points of course - something like 2 points for fixing up bad HTML, 3 points for a pure-text problem statement, 5 points for something with tables and such, and 7 points for something with diagrams (that you'd have to cut out and paste in), and 10 points for cleaning up diagrams (e.g. Bouncing Ball)

You should follow this template:
(Please take a look at the source of the other converted COCI/SMAC/etc problems for examples)

<h3>Category (e.g. Woburn Challenge 1999)</h3> 
<h2>Problem Name</h2>

<p>This is the problem description.</p>
<p>Please break it up into paragraphs.</p>
<p><img src=""></p>
<p>You may need diagrams.</p>

<p>Describe the format of the input here.</p>

<p>Describe the output format here.</p>

<h3>Sample Input</h3>
<pre>The pre tag gives it the "code" look.</pre>

<h3>Sample Output</h3>
<pre>Sample output here.</pre>