Design Video Sharing Platform

Start by clarifying the exact contract for Video Sharing Platform: input representation, mutation rules, duplicate behavior, and what should happen on invalid or empty input. The core idea is asynchronous media pipeline and authorization boundaries. Work a tiny example aloud and name the invariant after each step, because that is the proof that the approach stays correct as the input grows.

A dependable implementation plan is to clarify playback and privacy needs; upload directly to object storage; emit transcode work; store renditions and metadata separately; serve authorized manifests through CDN. Never mark a video ready before its rendition pipeline completes. Keep the code aligned with that invariant instead of adding special cases that silently change the contract. Test the smallest input, a normal case, duplicates or ties where relevant, an adversarial boundary, and a case that exercises the failure path. The expected complexity is metadata lookup is indexed; delivery scales via CDN. Explain both time and auxiliary memory, including recursion or helper structures; do not hide sorting, copying, or repeated scans. If the title omits critical constraints, say what you need to know before committing to a more specialized solution.

Complexity: With an indexed video catalogue, lookup is O(log n + k) for n videos and k returned results, while the stored catalogue is O(n).