Invitation to CodeChef July Lunchtime 2020

We invite you to participate in CodeChef’s July Lunchtime, this Saturday, 25th July, from 7:30 pm to 10:30 pm IST
3 hours, 5 problems.

If you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef’s contests, you can share them here.

Here is the problemsetting panel:


Top 10 Indian and top 10 Global school students from ranklist will receive certificates and CodeChef laddus, with which they can claim cool CodeChef goodies. Know more here.

Good luck and have fun!


Is the contest balanced ? :no_mouth:


I think the answer is pretty obvious.

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I hope ,Test cases are strong enough and contest is balanced in both divisions .

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5 problems in each divison?

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Problem BINFUN redirecting to PRT2. Please fix it!


Sir, Codechef server is not working. please help.


Yes Please fix it.

Please make it unrated round
Can somebody give a test case on which this solution fails :disappointed:

Input format for question 1 was incorrect which costed me a lot time and ranks because I am a python user, unknowingly cpp users didn’t got that issue because input taking in python and cpp for a list(array) is different, then after 10 minutes announcement was made on main page, which I am supposed to check but I couldn’t, then it took a lot of time for you guys to update the format on question page itself, I am actually so done with this platform now.

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I think out methods are very similar. Can someone help me in mine too.
I thought 1e6 was too small a number, that’s why I chose 2e7. Like the 10^{10} number in the sequence will not be described in the first 10^6 numbers.

I have another WA submission in which array size 1e7

Yup. I tried that too. Seems that we have the same bug

How to solve Golomb ?

int on line 32 must be long long int because of the multiplication on line 35.
See how I figured that out for humane here

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Thank You.
Wow. That was stupid from me. I should just use long long int everywhere.

I think the first problem of division 2 must be rejudged and ranks recalculated. There was an error in input format and the first question was solvable within 3 minutes but many people got WA/NZEC and then changed the input format to get the correct result. For sure costed a lot of ranks for many people. @admin

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Yeah, and then BINFUN whose partial was easy also was redirecting to some other question for a good amount of time, actually they don’t even consider your argument if you’re a python user because you aren’t representing majority, nvm.