We invite you to participate in CodeChef’s Starters 69, this Wednesday, 14th December, rated till 6-stars Coders (ie. for users with rating < 2500).
Time: 8 PM — 11:00 PM IST
Joining us on the problem setting panel are:
Contest Admins:Utkarsh Utkarsh.25dec Gupta, Satyam satyam343
Setters: Utkarsh Utkarsh.25dec Gupta, Satyam satyam343 , Nishank IceKnight1093 Suresh, Kanhaiya notsoloud1 Mohan, Wuhudsm wuhudsm, Akash Sharma, Deepak deepak_changoi Changoiwala
Testers: Nishank IceKnight1093 Suresh , Manan mexomerf Grover
Statement verifier: Kanhaiya notsoloud1 Mohan
Video Editorialists: Garvit garvitvirmani0 Virmani, Vibhu Vibhubhatia Bhatia, Madhav jhamadhav Jha, Suraj jhasuraj01 Jha, Jwala jwalapc , Rohit ezo_tihor Oze, Adhish ak2006 Kancharla
Text Editorialists: Nishank IceKnight1093 Suresh
Written editorials will be available for all on discuss.codechef.com. Pro users can find the editorials directly on the problem pages after the contest.
The video editorials of the problems will be available for all users for 1 day as soon as the contest ends, after which they will be available only to Pro users.
Also, 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.
Hope to see you participating. Good Luck!
Starters 69- NICE
This isn't usually a problem in Codechef, and I might be wrong here but PASSTHRU time limit for Java seems really tight. Too bad my C++ is rusty, I could not convert it within the contest.
TLE in Java. This was the closest I came to AC.
AC in CPP.
As for the problems, they seemed harder than usual (maybe it's just me losing touch).
The intended solution doesn't use small to large merging at all, but unfortunately we weren't able to stop it from passing in C++ (especially if some optimizations were used such as pragmas and/or fast hashmaps) so we decided to increase the TL a bit right before the contest; it's unfortunate that it didn't pass in Java (admittedly I don't know Java well enough to have tested that anyway). My C++ code runs in 0.7s so 2.5 seemed like a reasonable limit.
However, I will add that the intended solution is $$$\mathcal{O}(N)$$$ after building the virtual tree so I hope that's fast enough in Java, check out the editorial if you're interested.
Regarding difficulty: we expected way more solves on SORTPERM and ADJPAIRSWAP, but I'm guessing lots of participants got stuck on casework on them (or in DIVBYTHREE). ADJPAIRSWAP in particular has a rather clean solution with almost no casework, and SORTPERM is quite simple to implement after a couple of observations too.
I used small-to-large merging, but my implementation kept giving TLE, please can anyone help ?
My last submission
Using unordered map might be the reason for tle. You can look at my submission using simple arrays and vectors. Submission
Please make the announcement 1 day before the contest date on CF if possible from next time. :(
My rank was 18 in this contest.
But my rating increased just by +32. I was expecting to become 6 star this time :(
Check the rating increase of rank 1 in div2.
He got +3.
You have to get rank 1 20 times to get +60