In the first round, the algorithm question involved determining if a group of friends can be divided into two groups where no one in the same group is friends with each other. It seemed straightforward like a BFS problem, but I got stuck. The interviewer was really nice.
The second round was about system design, focusing on designing tiktok.com. Questions delved into how to stream videos on mobile devices with poor quality, hardware limitations, optimization strategies, serving the same URL from separate mobile and web repos, and implementing a caching system that updates every 10 minutes under normal circumstances and every 20 seconds under special conditions. I struggled with the questions, and the interviewer ended the interview without asking further. I can only blame my lack of skills. Perhaps for someone with a $100 phone like me, the advice would be to stop watching TikTok and quickly earn money to upgrade your device, my friend!