April Lunchtime 2017

Hi, Codecheffers!

I’d like you to invite for CodeChef April Lunchtime that will start at 19:30 IST today and will last 3 hours.
Note that the contest starts in about 2 hours!

Setters: Kamil Debowski, Ildar Gainullin, and big help from Praveen Dhinwa
. Main tester: Lewin Gan. Editorials: Misha Chorniy. Translators: Ildar Gainullin (Russian), Hu Zecong (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.

I wish you great fun and no frustrating bugs.
See you on the leaderboard.


You know that @errichto is problem setter when you see “limak” (the bear) in tags :stuck_out_tongue:


Are the editorials out yet?

Yes, they r out.

Best Lunchtime ever(for me).


Scoring Summing issues again? Codechef calculates 100+50+10=150 instead of 160.

That happens if u submit at the end of the contest. Wait for 15 mins. It will be fine.


Agree with @mathecodician . I loved the partial marking scheme here. Loved this one for sure! The graph problem was also nice…couldnt solve but i loved how it made me think.

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Actually here I wasn’t talking the problems. It was great for me because I came first in the Indian School Students. Although the best problems ever were in the February lunchtime.

Feb Lunchtime? Thanks for telling, i will look at its problem next. Personally i liked some concepts i learnt. Just happy atm :slight_smile: XD

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Nice problems indeed :slight_smile:

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Unfortunately not. Summed score is still 150 and now even the ratings are updated :frowning:

Try e-mailing codechef about it, they should fix it.

How to ask questions!?

Thanks for letting us know. We will fix that.


Thanks for fixing the sums. Will the ratings also be updated to reflect the changed ranks? It seems the rating change is still based on the old incorect ranking.