Be_dos's blog

By Be_dos, history, 3 years ago, In English

Hello CF!

I have a small suggestion about the EDU section. When we want to see AC submissions of some problem, we go to the "submissions" page. It looks kind of similar to the "status" page for archive problems. But if we look closer, there are some QOL-level differences.

The EDU version does not allow to sort submissions by time, submission size or whatever. Also, the filter panel is missing at all, so advanced features like filtering by number of failed test are not available.

It would be great to bring all this stuff to EDU. Also, if this is implemented, it would probably make sense to make the naming uniform across the board.

Hope someone from CF staff notices this.

P.S. Is it only me or does EDU work painfully slow compared to all the other pages?

Full text and comments »

  • Vote: I like it
  • +24
  • Vote: I do not like it

By Be_dos, history, 3 years ago, In English

Hello Codeforces!

Today I was solving 1038E - Maximum Matching during practice. I made submission 107130992. To my big surprise, it got AC with time 951 ms (less than half of TL). However, I have an easy-to-generate test which makes it work around 3000 ms! This indicates that the testcases are extremely weak.

The test is very simple: we can just distribute the 100 blocks evenly between all 6 kinds of pairs with distinct elements.

It's also interesting that it is possible to make that submission work fast enough even on that test (see 107131735). This means that one can wrongly get AC while being on the right track.

I know that this is quite an old problem. However, it might still be worth to throw in a few more tests so that submissions like my first one do get TLE in the future.

Tagging the problem author: Ashishgup

Full text and comments »

  • Vote: I like it
  • +20
  • Vote: I do not like it

By Be_dos, history, 4 years ago, In English

Hello everyone!

While browsing through the problemset, I often find tasks from rounds with various custom rules, such as "You can only use one language for one problem" or "You can only submit in language X". I see several problems with those tasks:

  1. Their difficulty value is a poor match to their real difficulty. A task that would have had difficulty 1500, had the round been normal, can easily be 2000+ on such one (fewer people submit => higher value). While filtering problems by difficulty, I often come across them, wonder why they are so easy and then notice some custom rule. That's quite annoying.

  2. Sometimes a problem is interesting by itself, but the whole thing is ruined by some restriction. It would be good if it were possible to submit all problems normally (they're there for practice, after all).

So, what are your thoughts on the topic? Share them below!

Full text and comments »

  • Vote: I like it
  • +19
  • Vote: I do not like it