[Frost1x]

That means the graph questions were only really relevant for the position where you maintain a graph based API. They were completely irrelevant for the other positions.

My guess is, even after working with graph algorithms for awhile, you still needed more than 20-30 minutes to make implementation changes and still needed to have a reference to look at while doing so.

I know for a fact graphs are quite useful. I also know complex algorithmic questions during an interview for most cases are also not useful. The fact you obtained the position and were able to adapt and still manage graph structures shows that those questions didn't gauge your fundamental abilities. Maybe you didn't hit the ground running day one, but after a little bit of learning/practice, you were fine under reasonable delivery conditions.