Faced a system design question about creating a URL shortener first, which felt a bit straightforward. Then came a coding challenge to find the longest palindromic substring, followed by implementing an LRU cache. While the overall difficulty was easy, I didn't feel challenged enough for a role at TikTok. Interestingly, a similar architecture breakdown was on PracHub during my prep, which helped me get through that part. I received an offer, but ultimately decided it wasn't the right fit for me.

Design a URL shortener system like TinyURL.

Find the longest palindromic substring in a string.

Implement an LRU cache with O(1) operations.