Question

I am trying to find a simple way to check whether a vector is a subset of another without sorting the order of elements in the vector. Both the vectors contain random number elements in them.

std::includes seems to work only for sorted ranges. How can I accomplish this?

Answer 1

Copy the vectors. Sort the copies. Then use std::includes on the copies.

template <typename T>
bool IsSubset(std::vector<T> A, std::vector<T> B)
{
    std::sort(A.begin(), A.end());
    std::sort(B.begin(), B.end());
    return std::includes(A.begin(), A.end(), B.begin(), B.end());
}