Template Parameter Pack

parameterpack.cpp

// http://kevinushey.github.io/blog/2016/01/27/introduction-to-c++-variadic-templates/
// https://en.cppreference.com/w/cpp/language/parameter_pack
// https://www.hackerrank.com/challenges/cpp-variadics/problem

#include <iostream>
using namespace std;

template <bool a>
int reversed_binary_value()
{
	return a; 
}

template <bool a, bool b, bool... d> 
int reversed_binary_value()
{
	return (reversed_binary_value<b, d...>() << 1) + a;
}

template <int n, bool...digits>
struct CheckValues 
{
	static void check(int x, int y)
	{
		CheckValues<n-1, 0, digits...>::check(x, y);
		CheckValues<n-1, 1, digits...>::check(x, y);
	}
};

template <bool...digits>
struct CheckValues<0, digits...> 
{
	static void check(int x, int y)
	{
		int z = reversed_binary_value<digits...>();
		std::cout << (z+64*y==x);
	}
};

int main()
{
	int t;
	std::cin >> t;

  	for (int i=0; i!=t; ++i) {
		int x, y;
		cin >> x >> y;
		CheckValues<6>::check(x, y);
		cout << "\n";
	}
}