Invitation to CodeChef May Long Challenge 2018!

Hello CodeChef Community!
The May Long Challenge 2018 is at your doorstep to treat you with a programming fixture for 10 exciting days. You surely wouldn’t want to miss this one! I hope you will join your fellow programmers and enjoy the contest problems. Joining me on the problem setting panel are:

I hope you will enjoy solving them. Please give your feedback on the problem set in the comments below, after the contest.

Contest Details:

Time: 4th May 2018 (1500 hrs) to 14th May 2018 (1500 hrs). (Indian Standard Time — +5:30 GMT) — Check your timezone.

Contest link:

Registration: You just need to have a CodeChef handle to participate. For all those, who are interested and do not have a CodeChef handle, are requested to register in order to participate.

Prizes: Top 10 global and top 20 Indian winners get 300 Laddus each, with which the winners can claim cool CodeChef goodies. Know more here: (For those who have not yet got their previous winning, please send an email to First to solve each problem individually: 100 laddus (For problems common to both Divisions, only one user will get laddus for that problem).


If i submit problems from the div2 page,despite being div1 would that be considered as practice problems or will i be considered to participate in may challenge?

Now, the long challenge has completed. So, can someone share his approach on the problem Change the Sign?


Here is my approach for change the sign… I have used algorithm for finding max sum subsequence such that no two adjacent are taken at a time(not only max sum but the subsequence also)… Have a look at my solution


Why my soln is giving WA in two test cases??
Please Help!!

ques - DBFB

Soln - soln

whats the approach for st mincut can anyone explain ??

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Cannot find the editorial of ST-MINCUT? Could someone please share the link?

Could anybody point out what is wrong with this solution for FAKEBS.

@vijju123 I was in div-1 and got 107 rank will I get 300 laddus ? I set filter to India in ranklist and if 20 different rank values are considered then I should get them.

Can some one please tell me where my solution is going wrong for FAKEBS!! This is my solution. This is another solution I’ve tried to the same question. Irony is that both of them failed for the same test cases :frowning:

How long till the editorials come out?

Also, there aren’t any editorials for April Lunchtime yet. ( The links are there but they redirect to a 404 )

Where is the editorial for May LONG Challenge?

Here are our editorials:

It’s mostly in layman’s terms, but if you need any kind of help, do not hesitate in wrtiting to us.

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Hello all,

In view of delay of editorials, I had a discussion with @mgch and @admin , and we decided that due to issues with current Editorialist, Problem Tester (Suchan Park) will now write the editorials. I assure you that this task is at highest priority for contest admin @mgch and @admin and they will try their best to provide you guys with quality editorials of the problems.


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Looking forward to some great problems!!! :smiley:

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Haha you forgot my name in the authors’ list :stuck_out_tongue:

@nileshjha19 but you don’t have access to the problem setting panel, cause you will participate in Div1 :stuck_out_tongue:

P.S. Added :slight_smile:

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Yo sure!

P.S. You take care of the comments xD

LOLOLOLOLOL XD. Nice one @nileshjha19 XD

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4th May to 14th February? CodeChef problem setters can reverse time wow :slight_smile: