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Invitation to CodeChef December Long Challenge sponsored By ShareChat

Hello CodeChef community,

You are invited to CodeChef December Long Challenge 2018 sponsored by ShareChat. This is a 10-day competition with 8 problems and it’s open to programmers across the globe. The contest problems will be available in English, Hindi, Bengali, Russian, Mandarin and Vietnamese.

Participants will also be in the running for some exciting jobs at ShareChat - India’s fastest growing social network. To apply, all you need to do is fill the application form on the contest page and participate in the December Long Challenge.

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.

This question is marked "community wiki".

asked 05 Dec '18, 09:34

mgch's gravatar image

accept rate: 20%

@mgch I have a clarification to ask. How can I do so privately?

(08 Dec '18, 11:38) avi2244★

ask in comment section below problem statement... (its private until admin makes it public).

(08 Dec '18, 12:31) l_returns5★

I have posted a blog on Interactive problems, which you may refer here!


answered 08 Dec '18, 01:28

taran_1407's gravatar image

accept rate: 22%

Well, what a day to start the Challenge , The Avengers 4 trailer is out . Hope the contest is balanced like everything should be. xD


answered 07 Dec '18, 20:55

zacky_901's gravatar image

accept rate: 0%

After seeing interactive problems -"I don't feel so good Mr mgch" :xD

(08 Dec '18, 00:32) pavitra_ag4★

So sorry to hear that, Mr pavitra_ag.. "January Long going to be more innovative" - anonymous

(08 Dec '18, 07:58) mgch6★

Waiting for January then :D

(08 Dec '18, 08:05) l_returns5★

@mgch : let's teach "how to attempt interactive problems" to everyone before acm-icpc XD
nice contest :D


answered 07 Dec '18, 17:16

l_returns's gravatar image

accept rate: 25%

edited 07 Dec '18, 17:17


@l_returns You can't prepare in the last moment before acm-icpc, it's not exams :) Some teams preparing for events like acm-icpc everyday for years.

(07 Dec '18, 23:44) mgch6★

yeah true... am also preparing since one year :)

(08 Dec '18, 00:17) l_returns5★

Well, My blog might come in handy for that.

(08 Dec '18, 01:26) taran_14076★

Just curious. When challenge problems are recalculated on all test cases after the end of the contest, does the system only use the last submission from each participant, or maximum from all submissions of each participant, or something else (like the last AC submission if any)?


answered 18 Dec '18, 20:29

shoom's gravatar image

accept rate: 22%


The system considers all correct submissions of each participant. The maximum score after recalculation is considered.

(18 Dec '18, 20:42) avi2244★

Thanks for clarification!

(18 Dec '18, 20:44) shoom6★

When can we expect the editorials to be out?

P. S. According to this, the editorials are done 5 days before the contest starts. So why aren't they released just after the contest ends?


answered 18 Dec '18, 22:01

psaini72's gravatar image

accept rate: 25%

Nice problem statements. @mgch

One question, Why didn't you tag @vijju123 ? He is really interested as I know xD


answered 07 Dec '18, 18:12

taran_1407's gravatar image

accept rate: 22%

edited 07 Dec '18, 18:14

Because he knows me better than you :).

To everyone else- Yes, @taran_1407 is officially pissed because of no @tarini_1407 in the statement. @mgch , requesting you to please keep that in mind in future.

(07 Dec '18, 22:09) vijju123 ♦♦5★

@taran_1407 it's coming.

(07 Dec '18, 23:47) mgch6★


Inserting Random Text.

(07 Dec '18, 23:53) aryanc4036★


Why not let user select on how many(/which) subtask he wants to run his code ?

This will boost submission waiting time and load on codechef server very much !!


answered 07 Dec '18, 23:18

l_returns's gravatar image

accept rate: 25%

edited 07 Dec '18, 23:19


Hmm, it's interesting idea. But who will use that & the sense? It's easier to select the full problem.

(07 Dec '18, 23:20) mgch6★

yes... it's easier to select full... but sometimes when number of subtasks is large then it would be much more convenient(for server as well as for user).
When user know it gonna be TLE, SIGSEGV in next subtask or he is getting wa in only a particular subtask.

(07 Dec '18, 23:29) l_returns5★

@l_returns Yes, I understand. But I guess not many people will use it fairly

(07 Dec '18, 23:32) mgch6★

No1 will actually opt for this because, well, why should I constraint my solution? Unless there is any penalty for too many wrong submissions on full subtask, why risk the $1$ percent chance that my unintended solution actually passes? :p

(07 Dec '18, 23:33) vijju123 ♦♦5★

yes true @mgch and @vijju123 , agree.
But , he can always submit it on all subtask once his intended subtask passes...
But till then when he is getting a lot of wa's / runtime errors , he will use it for speed.

(07 Dec '18, 23:40) l_returns5★

How about splitting WKPLAN into two parts similar to jadugar and have strict submission limit for subtasks with high tl?

(08 Dec '18, 11:12) aryanc4036★

@aryanc403, More subtasks = confusing.. Maybe pretests/systests, but it's weird.. About WKPLAN: I don't know how people will submit WKPLAN. It was not my idea to to make submissions limit = 50 tries there. As you see no one tried to solve it yet. However, 50 sumbissions should be enough.

(08 Dec '18, 12:28) mgch6★

Fifty submissions are something which I cross easily if I try to exploit something. So I'm a bit scared about it. Maybe 100? This is the reason why I suggested splitting it.

(08 Dec '18, 14:31) aryanc4036★
showing 5 of 8 show all

Is that challenge unrated?


answered 18 Dec '18, 20:03

buzz_95's gravatar image

accept rate: 0%

It is rated.

(18 Dec '18, 20:17) vijju123 ♦♦5★

When will the editorials for BHD, BICONT and WKPLAN be out?


answered 15 Jan, 19:41

mnaveenkumar20's gravatar image

accept rate: 0%


le me cut-copy-paste


Where did I write "An ideal problem has no test data." ??
But ya my actions meant that only?
Because I wanted to see a contest without weak test cases.
And I have 2 more memes on weak test cases lined up.
I a̶m̶ (was) (maybe) planning to post them.

Well Played.

P.S. - Where is vijju123 ?? :P

</copy >

N̶i̶c̶e̶ ̶p̶r̶o̶b̶l̶e̶m̶ ̶s̶t̶a̶t̶e̶m̶e̶n̶t̶s̶.̶ Will comment after the contest.
S̶t̶r̶o̶n̶g̶ ̶T̶e̶s̶t̶ ̶C̶a̶s̶e̶s̶.̶ Initial reports say something else. Waiting for confirmation. Will definitely comment after the contest. If required with a meme.

O̶n̶e̶ ̶q̶u̶e̶s̶t̶i̶o̶n̶,̶ ̶W̶h̶y̶ ̶d̶i̶d̶n̶'̶t̶ ̶y̶o̶u̶ ̶t̶a̶g̶ ̶@̶v̶i̶j̶j̶u̶1̶2̶3̶ ̶?̶ ̶H̶e̶ ̶i̶s̶ ̶r̶e̶a̶l̶l̶y̶ ̶i̶n̶t̶e̶r̶e̶s̶t̶e̶d̶ ̶a̶s̶ ̶I̶ ̶k̶n̶o̶w̶ ̶x̶D̶ One problem is still left. Who knows what @mgch decided to do with that.

@mgch : let's t̶e̶a̶c̶h̶ show "h̶o̶w̶ ̶t̶o̶ ̶a̶t̶t̶e̶m̶p̶t̶ ̶i̶n̶t̶e̶r̶a̶c̶t̶i̶v̶e̶ ̶p̶r̶o̶b̶l̶e̶m̶s̶ powers of @admin" to everyone before acm-icpc XD

P.P.S. - @taran_1407 @vijju123 will not be left alone. Either @mgch will do our task else we are here for creating one easy question :P

And at last Thank You. @mgch
P.P.P.S. - Decided to cancel another plan which I made initially.


answered 07 Dec '18, 18:28

aryanc403's gravatar image

accept rate: 10%

edited 07 Dec '18, 18:34

Either @mgch will do our task else we are here for creating one easy question :P

Whats up with this obsession xD. I dont have any fancy quotes which @mgch can cite publicly. xD

(07 Dec '18, 22:10) vijju123 ♦♦5★

Finally, I found one -
I dont have any fancy quotes - vijju123

(07 Dec '18, 22:37) aryanc4036★

@aryanc403 yes, we have the problem of weak test cases. But more test cases and CC queue is going to be long. So, seems only the way is to give output-only problems. CHFIDEAL really has no test data.

"And I have 2 more memes on weak test cases lined up."

P.S. I heard that you have memes. But someone said that you had 10... So, I just tried to save your time.

(07 Dec '18, 22:54) mgch6★

C'mon, even you know thats a very cheap way of framing a quote on me :/

(07 Dec '18, 23:34) vijju123 ♦♦5★
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question asked: 05 Dec '18, 09:34

question was seen: 1,948 times

last updated: 15 Jan, 19:41