never_giveup's blog

Invitation for June Lunchtime 2017
By never_giveup, 7 years ago, In English

Hello Codeforces!

I’d like you to invite for CodeChef June Lunchtime that will start at 19:30 IST of 24-th June 2017 (check your time zone here) and will last 3 hours.

The author of problems is me, never_giveup, while Lewin is a tester and mareksom is the secondary Tester. The editorialist is pkacprzak. Translators: CherryTree (Russian), huzecong (Mandarin) and VNOI team (Vietnamese).

There is no registration required, anybody with a CodeChef handle can participate. Top school participants can win CodeChef laddus (details on the contest page).

You will be provided 4 problems with subtasks (IOI-style grading). Ties are broken by time of reaching your final score.

Remember about subtasks if you can't solve a problem for the full score, and read the editorial after the contest.

  • Vote: I like it
  • +69
  • Vote: I do not like it

Comments Comments (13)
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7 years ago, # |
← Rev. 2   Vote: I like it +25 Vote: I do not like it

What error is this?

Also for some weird reason which i don't know O(N) per query worked for 2 subtasks while O(log^2(n)) per query worked for only 1 subtask.

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    7 years ago, # ^ |
    ← Rev. 2   Vote: I like it +38 Vote: I do not like it

    If you watch constraints in Codechef, you can see that there is memory limit 1500 MBs. I watched your submission and it uses >1800MBs. Verdict is not ML because there is no ML constraints like in codeforces or somewhere else. Also I see, that your next submission was the same as this except that you changed size of your array, so you should understand it by yourself.

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      7 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Thanks, i always thought codechef offers unlimited memory (As much as the compiler allows) but looks like i was mistaken.

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

Can't DSU on trees work for Company and Club Hierarchies?

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7 years ago, # |
← Rev. 3   Vote: I like it 0 Vote: I do not like it

Company Club Membership is very tricky :(.

Node change is from 0 -> n - 1 and repeat.

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7 years ago, # |
← Rev. 3   Vote: I like it +8 Vote: I do not like it

How many felt the same as me:

I felt for the three problems (except the easy) that they are a mix of very standard famous approaches along with a very easy idea (I was able to figure the idea of each problem in less than 5 minutes). and was too lazy to code any

It's not cool also the way the last 2 problems are being asked on the same tree structure. I am sorry, not trying to be a critic

But didn't enjoy a second

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7 years ago, # |
  Vote: I like it +11 Vote: I do not like it

Did anyone of you solved the 3rd problem after reading my recent blog post? I would be happy if someone did :D

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7 years ago, # |
  Vote: I like it +28 Vote: I do not like it

Guys, if you think that problems was too easy, then watch their difficulty. First problem should be solvable for everyone, who just started programming. Second problem should be solvable for 70% of participiants. Third problem should be solvable for 20% of participiants. And if you had some problems with testing. I'm sorry, they were. But correct solutions should pass for each subtask. I was testing each subtask by myself. I'm sorry, if you was disappointed.

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7 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

** deleted **

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

My N Log N solution passed for the 3rd problem when carefully implemented.

Code

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