Why My Sliding Window Solution Was Wrong (And What I Learned)

When I first solved a classic sliding window problem, I was confident my solution was correct. It passed a few test cases. But it was fundamentally wrong. This blog is about: What mistake I made Why it failed And the key insight that fixed everything The Problem Given a string s of uppercase letters and an integer k, we can change at most k characters. 👉 Goal: Find the length of the longest substring that can be converted into all identical characters. My Initial Thinking I used a sliding windo