Martynas's blog

By Martynas, history, 3 years ago, In English

Once again you are invited to participate in the online mirror of the final stage of Lithuanian Olympiad in Informatics!

The format of the competition is similar to IOI: 2 days with 3 tasks in 5 hours, just the choice of languages is more limited (programming: C/C++, statements: English/Lithuanian). Day 1 contest will start on Friday, March 23 at 15:00 UTC and day 2 on Saturday, March 24 at 9:00 UTC.

See online.lmio.lt for more information.

Update: Congratulations to the winners! See the results of online and onsite contests.

Online:

  1. shadowatyy
  2. Kuha
  3. Sonechko

Onsite:

  1. Gediminas
  2. ___tutis___
  3. Kepperoni
 
 
 
 
  • Vote: I like it
  • +35
  • Vote: I do not like it

»
3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

At the same time we have our national competition so I won't be able to participate in online mirror. Can you please leave server open for at least a few days (like analysis mode) so I can make my own "virtual competition" (problems from previous years were very interesting and I would really like to take part)?

  • »
    »
    3 years ago, # ^ |
      Vote: I like it +8 Vote: I do not like it

    Yes, most likely there will be analysis mode after both contests finish.

»
3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Auto comment: topic has been updated by Martynas (previous revision, new revision, compare).

»
3 years ago, # |
Rev. 2   Vote: I like it +5 Vote: I do not like it

Where can I find previous years' problems?

  • »
    »
    3 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    Good question. 2015 problems are here, and I'll find the other years later.

»
3 years ago, # |
  Vote: I like it +6 Vote: I do not like it

What does the 'M' in 'LMIO' stands for? And it is "Lithuanian Olympiad in Informatics", but why is the short form 'LMIO' but not 'LMOI'?

  • »
    »
    3 years ago, # ^ |
      Vote: I like it +16 Vote: I do not like it

    LMIO is the initialism of the Lithuanian name of the olympiad, and there M is for "mokinių", which means "pupils'" (the participants are high school students).

»
3 years ago, # |
  Vote: I like it +23 Vote: I do not like it

Here are my ideas for problem A and B —

Problem A
Problem B

How to solve C?

  • »
    »
    3 years ago, # ^ |
      Vote: I like it +17 Vote: I do not like it

    There is a faster solution to B. For each vertex consider triangles that have smallest edge opposite to this vertex (otherwise that triangle will be considered from other vertex), If this triangle doesn't use two highest edges of this vertex, we'll get better answer by replacing third edge with biggest edge from this node, so for each node we only have to consider triangle formed by two biggest edges from this node.

  • »
    »
    3 years ago, # ^ |
    Rev. 2   Vote: I like it 0 Vote: I do not like it

    Can you please tell me how you managed to do first part in ? I got the same idea but I got an extra log2(n) factor because I used set to find element in larger set?

    • »
      »
      »
      3 years ago, # ^ |
        Vote: I like it +5 Vote: I do not like it

      I used unordered_map<int, int> v[N] for that. Though it is not true O(1), but it passed.

»
3 years ago, # |
  Vote: I like it +1 Vote: I do not like it

Have the servers died?

»
3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

The site was (and still is) lagging during the last 10 minutes (and I also had a submission that was stuck on compilation), and is now down for me (504 gateway time-out).

Does anybody know anything about it?

»
3 years ago, # |
  Vote: I like it +2 Vote: I do not like it

How to solve problem A and B from day 2 ?

  • »
    »
    3 years ago, # ^ |
    Rev. 2   Vote: I like it +9 Vote: I do not like it

    B is easy, but A is pretty hard! C needs too many strategies...

  • »
    »
    3 years ago, # ^ |
    Rev. 7   Vote: I like it +1 Vote: I do not like it
    Problem A
    Problem B
  • »
    »
    3 years ago, # ^ |
    Rev. 3   Vote: I like it +6 Vote: I do not like it

    Here are my solutions for A and B, I hope they can be understood even though they're not very formally written.

    Solution for A
    Solution for B
    80p solution for C
»
3 years ago, # |
  Vote: I like it 0 Vote: I do not like it

Will the LMIO problems be available on some judge after the analysis mode?

  • »
    »
    3 years ago, # ^ |
      Vote: I like it +5 Vote: I do not like it

    I'm not sure, but they'll probably be available on http://olimp.mif.vu.lt – it currently has the tasks of all other LMIO rounds from the last two years (no problem statements in English, however).

»
3 years ago, # |
  Vote: I like it +3 Vote: I do not like it

Why don't ojuz upload LMIO problems?

  • »
    »
    3 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    Do they make judge data public?

    • »
      »
      »
      3 years ago, # ^ |
        Vote: I like it +6 Vote: I do not like it

      Actually we didn't know the existence of this contest because there wasn't any request :( It seems tests are not provided now, I could only download 2015's one. From this comment, it seems they have their own grading system.

  • »
    »
    3 years ago, # ^ |
      Vote: I like it +3 Vote: I do not like it

    It seems it is possible to download the tests from the analysis mode. If we are allowed to upload those problems (since they have their own grading system) and we have English statements, we will start uploading

»
10 months ago, # |
  Vote: I like it 0 Vote: I do not like it

You can solve all problems here: https://oj.uz/problems/source/472