#include <iostream>
#include <tuple>
#include <unordered_set>

using namespace std;

template <class T>
inline size_t hash_combine(std::size_t seed, T const& v) {
    return seed ^ std::hash<T>()(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
}
namespace std {
template <typename... Ts>
class hash<tuple<Ts...>> {
 public:
    size_t operator()(const tuple<Ts...>& t) const { return impl<0>(t); }
    template <size_t Index>
    typename enable_if<Index == tuple_size<tuple<Ts...>>::value, size_t>::type
    impl(const tuple<Ts...>& t) const {
        return 0;
    }
    template <size_t Index>
    typename enable_if<Index != tuple_size<tuple<Ts...>>::value, size_t>::type
    impl(const tuple<Ts...>& t) const {
        return hash_combine(impl<Index + 1>(t), get<Index>(t));
    }
};
}


int main() {
    auto t = make_tuple(1, 2.0, string("abc"));
    cout << hash<decltype(t)>()(t) << endl;
    cout << hash_combine(hash_combine(hash_combine(0, string("abc")), 2.0), 1) << endl;
    return 0;
}