Using C++ Boost Library in Interviews

I was solving a Leetcode problem which required me to save std::pair objects into a Hash Set. However the std::unordered_set in C++ does not allow you to store pairs as they are not hashable by default. Hence, I decided to try and use Boost’s Hash function library as a custom hash function. Leetcode editor was unable to find the Boost library files, but how would this go down in an interview if I did something like this? Would an interviewer care?

And yes, in such an interview I would most likely just use Python and make my life 10x easier. But im just curious to know how this would play out if I did elect to use C++.