LRU Cache with a TTL Twist, Passed With Unfinished Code

TikTok engineer position, first round (technical screen). A variant of the classic LRU Cache problem (LeetCode 146). First the interviewer introduced themselves, then asked me to introduce myself. Then the interviewer asked: why are you looking to switch jobs, and why TikTok. Then it was on to coding — the classic LRU Cache problem, but with an extra requirement: support for TTL. Specifically, TT…

Shared by a candidate · reported Apr 2026. Interview formats change; use it as a guide, not a script.