TikTok Software Developer interview questions

Emailed pre-screen. 1-1 code interview. The interviewer was clearly not paying attention throughout the whole process, even claiming that he was very busy and needed to work. After implementing the brute force solution, he made me waste time writing up unit tests and then refused to give hints or anything about a more optional solution. Then he ended the meeting abruptly a whole 15 minutes early. Worst interview experience so far.