CC150 17.4

17_4.cpp

/* CC150 17.4 */
// find the maximum of two numbers without if-else or any comparison operator

#include <iostream>

int sign(int n) { return (n >> 31) & 0x1 ^ 1; } // 1 for positive and 0 for negative

int maxNumber(int a, int b)
{
	// if ab < 0, return the positive one, filt = sign(a)
	// if ab > 0, filt = sign(a - b) (which would not overflow since a, b have the same sign)
	int difSign = sign(a) ^ sign(b);
	int filt = difSign * sign(a) + (1 - difSign) * sign(a - b);
	return filt * a + (1 - filt) * b;
}

int main()
{
	int a, b;
	std::cin >> a >> b;
	std::cout << maxNumber(a, b) << std::endl;
	return 0;
}