Maybe they didn't give you the same sets of problems most companies use.

Last time I went through any of these one of the problems was implementing a priority queue, for which I would have to write a min-heap on the spot. There's no chance I'd be able to do it on 45 minutes with an interviewer breathing down my neck.

In other situations I had easier ones. I don't remember the problems especifically but I recall one I googled after the interview and the answer was using two-pointers fast/slow to iterate through a list. I spent maybe 20 minutes tryng a couple different approaches and that one never occurred to me. Last time I had to use a two-pointer solution for a problem was at uni, which I left 15 years ago.