### Ashishgup's blog

By Ashishgup, 2 months ago,

We invite you to participate in CodeChef’s July Cookoff, today — 28th July, from 8:00 PM — 10:30 PM IST. Note the unusual time.

There will be 7 problems in all divisions.

The contest will be rated for all three Divisions. The July Cook-Off also marks the launch of our new prize structure for global & Indian participants. More details are given below.

Joining us on the problem setting panel are:

Problem Submission: If you have original problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.

Prizes:

Global Rank List:

• Top 10 global Division One users will get \$100 each.
• Non-Indians will receive the prize via money transfer to their account.
• Indian users will receive Amazon vouchers for the amount converted in INR.

Indian Rank List:

• Top ten Indian Division One coders will get Amazon Vouchers worth Rs. 3750 each.
• The rest in the top 100 will get Amazon Vouchers worth Rs. 1500 each.
• First-time winners in Div 2 who make it to the top 200 for the first time will get Amazon Vouchers worth Rs. 750 each.
• First-time winners in Div 3 players who make it to the top 200 for the first time will get Amazon Vouchers worth Rs. 750 each.

The video editorials of the problems will be available on our YouTube channel as soon as the contest ends. Subscribe to get notifications about our new editorials.

Good luck and have fun!

Edit: Contest is extended by 15 minutes.

• +163

 » 2 months ago, # |   +27 Finally a rated contest after a month.
 » 2 months ago, # |   -35 is it postponed?
 » 2 months ago, # |   0 what means by first time , from now on or those who is new to cc and won in first contest or those who is old but came in 200 for first time
 » 2 months ago, # |   +25 :( internal error occurred in the system
•  » » 2 months ago, # ^ |   +23 Sorry, it will be fixed in a minute.
 » 2 months ago, # |   +5 speed chef
 » 2 months ago, # |   -8
 » 2 months ago, # |   +32 GCDLEN Intented soln
•  » » 2 months ago, # ^ |   +9 the obvious way takes $O(\log^2C)$ time, we'll have to do better I didn't have to, this easily passed in 1.5s
 » 2 months ago, # |   +33 Why you want people to get useless WA in https://www.codechef.com/COOK131B/problems/MODEQUAL due to integer overflow? What's wrong with having A[i]<=1e9?
•  » » 2 months ago, # ^ | ← Rev. 2 →   -32 That's why some people always use 64 bit integers.
 » 2 months ago, # |   +50 SPTREE2 Solution Maintain the endpoints of the special nodes dynamically (without type 2, it would be easy I think, and to deal with type 2 — we can use this). We only care about these 2 nodes. Also find the endpoints of the diameter of the complete tree initially Let the endpoints of diameter of tree be T1 T2, and of the special nodes be S1 S2 Consider all pairs (Si, Tj): The answer, if it exists, will be the Kth node on one of these 4 paths (which we can easily check if it is valid or not — and find as well, using binary lifting/lca) The dynamic endpoints of the special nodes can be maintained online through a segment tree as well.
 » 2 months ago, # | ← Rev. 2 →   +57 Ashishgup, Will it be possible to postpone (by 2 hrs) July Lunchtime as it is clashing with ICPC practice session.
•  » » 2 months ago, # ^ |   +9 If we postpone it, it will clash with TCO R4. It seems that the clash in unavoidable :(
 » 2 months ago, # |   +74 I was not aware that contest is extended by 15 mins. I closed my laptop and after 2 mins later I realised it's been extended. As many new features have been added in Chef (copying sample input) please also make a pop up feature for any announcement.
•  » » 2 months ago, # ^ |   0 Also, doubt support too. As we can ask for clarification of problems on codeforces, a similar thing should also be there on CodeChef.
•  » » » 2 months ago, # ^ |   +25 You can ask for clarifications in the comments — we answer them during the contest! But yes, I agree — clarification support system should be better.
•  » » 2 months ago, # ^ |   +33 Issue with pop-up is that CodeChef does not have a registration system yet, so the notification would end up being pushed to everyone using the site at the time.I believe CodeChef is working on adding this feature in the future — since it has non-trivial backend work, it may take some time though.I believe it's the most important feature required right now.
 » 2 months ago, # |   -16 Why aren’t you make a team for banning those YouTube channel who spoil the excitement of contest by upload logic even full AC code durning contest?
•  » » 2 months ago, # ^ |   +38 It turned out that today the distributor could not upload the code faster than me solving the problem (Div 2 Till D), So I'm happy that i did not get affected by cheating and all. Hence, The only solution to this scenario is to just get better than the distributor. Perhaps, It's quite challenging but exciting at same it :)
 » 2 months ago, # | ← Rev. 4 →   +8 I got WA for one of my solution. So i spent time debugging it.At the last second i did not change anything that could change output but AC anyway. I resubmitted WA solution got AC after the contest. WA verdict sol now showing AC but no announcement about changing test data. why? p.s: There was an announcement but no pop up.(new at chef). But still i did one wrong submission for this error.Issue has been fixed. Tnx to chef jumped up few ranks :p
•  » » 2 months ago, # ^ |   +4 In interactive problem, generally you don't have to flush output between consecutive lines. But in the 4th problem today solutions which were not flushing output between consecutive lines got WA. They corrected it after contest.
•  » » » 2 months ago, # ^ | ← Rev. 3 →   +8 Tnx, now i got it!
 » 2 months ago, # |   -28 how much rating would codechef reduce for gennady.korotkevich.
 » 2 months ago, # |   0 Why codechef don't have more rated contests as Codeforces have?
•  » » 2 months ago, # ^ | ← Rev. 2 →   +20 Maybe lack of problem proposal is one of the reason. Second reason maybe the cost of contest that is roughly INR 4-5 Lakh which in Codeforces is in some thousands. I don't think the money might be the great factor but ya it can be one of the reason, lack of problem proposal remains at first
 » 2 months ago, # |   +28 As someone who used to hate codechef for their server issues every contest and stopped participating, I must say that the quality of the problems has really gone up! And now I am more excited about the next Lunchtime than CF round 735 :P Can't believe I said that. Kudos to the problem-setters and the admins. All the best!
 » 2 months ago, # |   +11 Ashishgup Can you clarify what it means to be Indian in this context? What if one doesn't live in India but has overseas citizenship?
•  » » 2 months ago, # ^ |   +16 Only Indian citizens are considered for the prizes. OCIs are not considered.
•  » » » 2 months ago, # ^ |   +3 When can we get those prizes?
 » 2 months ago, # |   +5 Can someone explain how to solve Beautiful Subsequence? I am not able to understand the editorial.
 » 2 months ago, # |   +16 Are memory limits on the problems still 1.5 GB ? If not, can you guys add a tab which shows the memory limit of a problem ?
•  » » 2 months ago, # ^ |   +19 Yeah, the memory limit is still 1.5 GB for the problems, as far as I am aware.
 » 2 months ago, # |   +5 How to solve MATBEAUT (Make the Matrix Beautiful)?
•  » » 2 months ago, # ^ |   +31 Intented solutionGiven a permutation of length $N$ one can sort it with N-1 swaps. One can sort first $M-1$ columns using atmax $(N-1)*(M-1)$ using operations with $y_2=M$.Now if the no of inversions in the last column is odd then the answer is $-1$ (proof left as an exercise for the reader until the editorial is out).If $N \leq 2$ or $M \leq 2$ then we cant sort last column if it isn't sorted yet. Otherwise, on work out on paper a way to cyclic shift 3 numbers in last column using 4 operations. Repeatedly cyclic shift 3 numbers to get one number at its correct position. It needs atmax $4*(N-2)$ operations.Overall atmax $(N-1)*(M-1)+4*(N-2)$ operations.Tester soln if you want to refer it.
 » 2 months ago, # | ← Rev. 2 →   0 Can anybody help me in this problem Beutiful Subsequence How can I optimize dp solution ?
 » 2 months ago, # |   +26 When will we receive the mails regarding prizes for this contest?
•  » » 2 months ago, # ^ | ← Rev. 2 →   +9
•  » » 2 months ago, # ^ |   +6 Within 4 weeks, admin clarified it already
•  » » 5 weeks ago, # ^ |   +10 Did anyone receive the mails regarding prizes for the contest yet? It has been over 4 weeks now ..