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).


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:


@swetankmodi You are an observer! :wink:

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Or perhaps-

4th May 2018 to 14th February, 2019.

I notice how the contest is ending abruptly at Valentines day. Chef will be busy or what? :stuck_out_tongue:

@swetankmodi 14th February is a very nice day :slight_smile: Not only time :smiley:

Thanks, fixed.

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Very true @mgch . There are usually back to back 3-4 contests in a row that day. Very nice day indeed :slight_smile: :stuck_out_tongue: :stuck_out_tongue:

@vijju123 you should prevent time travel before the blog will be posted for the next time! :smiley:

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I’ll do whatever is in my power to stop that :stuck_out_tongue: XD :slight_smile:

@vijju123 it’s fun to take part on the contests that day since most of us are free :stuck_out_tongue:

@mgch Welcome :slight_smile:


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?

never got that opportunity :stuck_out_tongue:

Solving div2 Questions from div1 will not affect your ratings. In case they do, it will be a bug and you can get opportunity of getting codechef laddus from @admin :stuck_out_tongue: X)


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


Besides, @vijju123, @mgch, @admin, please add problems to practice section.

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