There are multiple interview stages. Depending on which round you are on will determine the type of interview.

For the first round, I had to solve two medium-level questions that I recognized from LeetCode.

They send you a link, and you must solve the problems within a designated time limit.

I heard that if you don't achieve 100% completion within the allotted time frame, you won't get a callback for the next step.

It was a medium-level difficulty question from LeetCode. I assume they change them all the time, so I would just refresh your knowledge on the company's 75 questions from LeetCode, and it will probably be in there.