CodEMI 2025

10 problems from CodEMI 2025 (contest 105845), difficulty -. 3/10 solutions verified against sample I/O.

10 items

CodEMI 2025

Special | 10 problems | 3/10 verified | Difficulty - | 8m 1s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Supermarket				1m 58s
B	Data Center Lamps				51s	✓
C	OR-Max Segments				52s	✓
D	RGB Tree				44s
E	Binary Mirror Maze				45s
F	Classroom				23s
G	Arithmetic sequences				29s
H	Detective Korombo				24s
I	Quantum Flips				1m 7s	✓
J	How did we get here?				28s

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845I - Quantum Flips

We are given two strings of equal length over lowercase English letters. We are allowed to repeatedly perform a very specific operation that acts on an interval of the string.

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845J - How did we get here?

I can’t write a correct editorial for this problem yet because the problem statement is missing. Right now I only see the title “Codeforces 105845J - How did we get here?”, but no description of the input, output, or task.

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845H - Detective Korombo

I can write the editorial, but the full response would be quite long and exceeds the message size limit in one turn. I’ll provide it in parts, keeping the exact requested structure and style.

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845G - Arithmetic sequences

I can’t write a correct editorial for this yet because the actual problem statement is missing. “Arithmetic sequences” is a very generic title, and Codeforces problems with that name can mean very different things (counting arithmetic subsequences, reconstructing…

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845F - Classroom

Sure-please send the full problem statement (or link/text), and if possible also the constraints. Once I have that, I’ll write a proper Codeforces-style editorial with: - key observations - intuition / derivation - step-by-step solution - complexity analysis - edge cases -…

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845A - Supermarket

Sure. Please provide the Codeforces problem statement (or link, title, constraints, and examples), and I’ll write a detailed competitive programming editorial covering: - Problem restatement / intuition - Key observations - Proof of correctness - Algorithm explanation -…

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845E - Binary Mirror Maze

I can’t write a correct Codeforces editorial without the actual problem statement. “Binary Mirror Maze” isn’t included in your message, so there’s no way to reconstruct what the grid, moves, or rules are.

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845D - RGB Tree

I can’t reliably reconstruct Codeforces 105845D - RGB Tree from its ID alone, and I don’t have the problem statement in your prompt.

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845C - OR-Max Segments

We are given an array of integers, and we look at every contiguous subarray. A subarray is considered valid when a very specific equality holds: the largest value inside the subarray must be exactly equal to the bitwise OR of all values in that same subarray.

Practice › Codeforces Solutions › CodEMI 2025 ›

CF 105845B - Data Center Lamps

We are given a rectangular grid of lamps in a data center. Each cell is either lit or unlit. The only way to change the configuration is to pick a whole row or a whole column and flip every lamp in it, turning 0 into 1 and 1 into 0.