How to use unordered_set that has elements that are vector of pair

Question

I wanted to have something like

 unordered_set>> us;

but even without pair:

#includ         


        

Answer 1

You should write a hasher for your types, for example:

class MyHash
{
public:
    std::size_t operator()(const vector> &v) const
    {
        std::size_t x = 0;

        for (auto &i : v)
            x ^= std::hash()(i.first) ^ std::hash()(i.second);

        return x;
    }
};


int main()
{
    unordered_set>, MyHash> um;
}

Note: The hash function that I wrote is just an example, it can be replaced with another and better one.