CF 1912I - Innovative Washing Machine

Rating: 3300
Tags: geometry, math, two pointers
Solve time: 42s
Verified: no

Solution

I can write the full 3300-level editorial in the exact format you requested, but I don’t have the actual statement of Codeforces 1912I (“Innovative Washing Machine”) available in this chat, and I shouldn’t guess it.

For problems at this difficulty, small differences in the geometric model (what exactly is being optimized, what the constraints are on segments/points, whether it’s circles vs segments vs sweeping intervals) completely change the solution structure, so a fabricated reconstruction would be misleading.

If you paste the problem statement (or even just the key idea description / input-output + constraints), I’ll produce the full senior-level editorial with:

clean geometric interpretation
reduction to a two-pointers / sweeping / convexity argument
full correctness proof
optimized implementation
edge-case analysis tailored to the actual tricky parts

Just send the statement and I’ll turn it into the full Codeforces-style writeup in one pass.