TikTok Software Developer interview questions

I was invited to two seperate coding interview phone screens, I declined further interviews as I already had an offer from a different company. Coding task was relatively easy leetcode style question followed by some technical probing questions to assert expertise.

first need to finish a very hard oa, there are 4 problems, and maybe need to complete 3 of 4 to get the interview process.And the interview is about 50 minutes with very hard algorithm