#include <bits/stdc++.h>
using namespace std;

const int RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
/*const long long RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();*/


struct HASH {
    template <class T>
    std::size_t operator()(T x) const { 
        return hash<T>{}(x ^ RANDOM ); 
    }
};

int main(int argc, char const *argv[])
{
    unordered_map<int, int, HASH> table;
    /* unordered_map<long long, int, HASH> table; */

    return 0;
}

If my map key is int type I've to write const int RANDOM

If my map key is long long type I've to write const long long RANDOM

blah blah ......

How it can be better using Template?