ByteDance Backend Software Engineer interview questions

Only managed to get the first round interview, an online coding session with a senior developer. The question is relatively hard and the interviewer will not give hints. There are no other questions available if you fail to answer the question.

First interview, about thirty minutes, asked a dozen questions, half of which were for the project on the CV. Medium difficulty. Mainly examine the basic skills. Friendly interviewer, very polite, no guidance.