I was recommended by a former Bloomberg employee. They contacted me in a week or two and scheduled a Skype video call.

Two guys were present: one was a native speaker, and the other had a Russian accent.

We started with a technical problem: grouping strings from a vector by anagrams. Then, because of my mistake in sort(vector), they asked how all STL methods work. I fixed my mistake, and we talked about different iterator types.

Questions followed about functors you can pass to STL functions, then about metrics and their properties. After that, we moved to machine learning.

Group strings in a vector by anagrams.

What do nearly all STL functions have in common? (Iterators as arguments.)

Suppose we have a big company and receive a lot of job applications every day. How do we solve the problem of finding the best position for an applicant?