[fjp]

I once passed a whiteboard interview just calling random made-up operations on generic java arrays, like Array.flatten().

I was relatively new to programming and had been practicing in Java but didn't know how to execute a lot of map/filter/reduce operations off the top of my head like that. I did, however, know that my interviewer was a Python programmer that probably didn't know much about Java language features.

[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.

[sanderjd]

If you can explain what it is supposed to do, I don't care a whit if you make up a method that probably exists in a standard library somewhere (Guava / Apache Commons, or wherever). If it's slightly more obscure, you might have to write pseudocode to show you know how it might be implemented.