Sliding‑window coding drill

- A new YouTube full course focuses on the sliding window algorithm pattern, a frequent interview technique for substring, subarray and streaming problems. - The video covers fixed vs variable windows, state maintenance, frequency maps and invariants used to lower brute force solutions from O(n²) to O(n). - Practicing this pattern helps bridge algorithmic thinking to production topics like rate limiting and rolling metrics; the course is hosted on YouTube. (youtube.com)