NVIDIA Formal Verification Engineer interview questions

I was asked to implement a 4-bit priority encoder using basic gates , and if i want to add one more bit how many gates i must add? and then to implement an SR flip-flop using D flip-flops — first with asynchronous Set, and then with asynchronous Reset.

After HR call they set up a technical interview which is a an ordinary technical interview process, 2 hours with 3 technical questions about digital design. In the Interview they talk about the company and role and then they ask about you.