kunyavskiy / ioi-on-codeforces

What is this

This project is an issue tracker for codeforces instance of IOI problems archive.

What should I do here?

• Help with problem materials
  • Pull request with fixing typos in statements
  • Provide missing statements in Russian
  • Provide statements in other languages, if you are ready to commit to doing that for a significant amount of problems
  • Pull request better validators (e.g., validate groups or add them to problems where there are no validators)
    • Most new problems had validators in the archive, but they are not polygon-compatible. Adapting them should be easier than writing new ones.
  • Send generators of better test data to issues
    • Do that only for problems containing validator.
    • Do that only for problems with subtasks, as otherwise, it significantly changes scoring
    • If the test is valid only for some subtasks, the validator should support validating subtasks.
• Report misconfigurations of codeforces problems with issues
  • Inconsistencies between statements and problem materials
  • Missing materials
  • Wrong scoring
  • Wrong subtask for some tests
    • Best way to report this is to provide a validator that supports groups for the problem.

Please, if you plan to make some significant effort, arrange it in advance with me. I can't guarantee that every work will be adopted.

What shouldn't I do here?

• Ask for help with solving problems - use codeforces forum or read editorials instead

ioi-on-codeforces's Issues

IOI 2017 Ancient books: wrong group dependencies

It looks as if group 4 depends on group 3 but this should not be the case ($n \le 1000$ does not imply $s = 0$)

(Minor) IOI2021F Registers

Here is the problem link.

The attached grader file is not the same as the grader described in the statement and the actual correct grader in on the official 2021 website

Also, the attached archive does not contain sample input files for the grader.

Nowruz judging is not working.

Currently nowruz from 2017 doesnt seem to be working correctly. I (definitelynotmee on cf) submitted my outputs that got around 70 points on oj.uz and it got 100 points here.

Also since you guys added the sample in the input file, the range of the important test cases goes from 2 to 11 instead of 1 to 10 like the original, and its kind of aesthetically unpleasing and annoying to format (ofc, just a nitpick, the 100 points thing is much more important lol).

IOI 2002 XOR is listed as regular problem instead of output-only problem on Codeforces

Problem link

The statement for XOR says that it's an output-only problem, but on Codeforces you are required to submit code instead of a zip archive.

Standings issue

Hi! I did IOI 2007 virtual a few days ago. I got 25 points on problem C, but then I resubmitted a little later and got 5 points. The standings of the contest show 25 points ( https://codeforces.com/group/32KGsXgiKA/contest/103750/standings ), But in the other standings ( https://codeforces.com/group/32KGsXgiKA/customrating/3853 ) it shows 5 points. I don't really know if the points of last submission matter or the points maximum overall. Kindly fix it (strikethrough : such that I get 25 on both). Thanks.

An issue in IOI 2010 Day 2 Problem 4 (2010 - H, Saveit)

The issue is in the grader file. The task says that you can do encode_bit(b) where b is either 0 or 1, but the grader allows for any value. So, we can basically store integers, this way we can just for every pair of vertices (u, v) encode_bit(dist(u, v)) and then get this distance in decode and just call hops on it. (This will only take H * N calls to encode_bit). Kindly fix the issue and rejudge the submissions.

Thanks.

Ghulam Junaid.