[seanmcdirmid]

I thought you were allowed to assume functions you needed in the interest of a modular solution. Array.flatten is an obvious “assume I have this, I would write it anyways.”

I think most decent interviews will give you a pass on an enhanced standard library.

[Zelizz]

When doing an interview at Google in C, I asked if I could assume I had a hashtable implementation with so-and-so interface, and the interviewer said no ¯\_(ツ)_/¯

[yoz-y]

This depends on the question but I assume that in this case the interviewer wanted a different solution than one using a hash table.

[seanmcdirmid]

Ouch. Well, most hashtables in C are custom, I guess.