We invite you to participate in CodeChef’s Starters 141, this Wednesday, 3rd July, rated till 5-Stars (ie. for users with rating < 2200).
Time: 8:00 PM — 10:00 PM IST
Joining us on the problem setting panel are:
- Setters: Nishank IceKnight1093 Suresh, Abdul Nayeem AKMalice Khalid, Archit Pols_Agyi_Pols.
- Tester: Archit Pols_Agyi_Pols.
- Text Editorialist: Nishank IceKnight1093 Suresh.
- Statement Verifier: Nishank IceKnight1093 Suresh.
- Contest Admin: Nishank IceKnight1093 Suresh.
One problem has a subtask.
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 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!
Greater
As a tester, good luck to all participants, and I would recommend the participants to read all the problems.
How many problems in each division?
7 in Div.4, 6 each in Div.3 and Div.2, 5 in Div.1
One problem has a subtask, and is present in all 4 divisions.
My stream discussing all problems except last
Is Possible Contender a repeated problem?
If yes then link the original problem
I couldn't remember, but I think I have seen this problem before
1975C - Chamo and Mocha's Array
This problem might be the reason why you feel so.
Btw it took me quite a non trivial amount of time to get it right, despite knowing codeforces problem.
Yes, that was the problem I was talking about.
Thank you
I solved the cf problem in like 15 minutes in the contest but couldn't get a solution to this problem during the whole duration of this contest. Except for the median I am not finding anything similar but yes this problem may be the inspiration I don't know.
Detailed Video Editorial
Amphibian : https://youtu.be/aS667Vq9Cq8
Perfect Prefixes : https://www.youtube.com/watch?v=_GLRN690L0Ihttps://youtu.be/aS667Vq9Cq8
My DP attempt at Perfect Prefixes: We note the initial score of the permutation, then try to swap elements and see their impact on the score. If we keep track of the MEX, we can tell whether a swap will increase or decrease the score by 1. Use DP to find the subarray of swaps with the highest sum. The mex logic was a little messy, but it worked.
Nice div2 C
Could someone recommend more problems like Central Cutting where you need to tally the values of a certain function over partially filled combinatorial objects (a permutation of length $$$n$$$, an array of length $$$n$$$ with elements from $$$1$$$ to $$$m$$$, maybe even a node- or edge-labeled tree with some labels missing)?