1748D - ConstructOR - CodeForces Solution

#include<bits/stdc++.h>
using namespace std;
long long a, b, d, k, x;
int T;
int main() {
	for(scanf("%d", &T); T --; ) {
		k = 1, x = 0;
		scanf("%lld%lld%lld", &a, &b, &d);
		int f = 0;		
		for(; d % 2 == 0; a >>= 1, b >>= 1, d >>= 1, k <<= 1) {
			if((a & 1) || (b & 1)) {
				f = 1;
				break;
			}
		}
		if(f) {
			puts("-1");
			continue;
		}
		for(int i = 0; i < 30; ++ i)
			if(!(x >> i & 1))
				x += (1ll << i) * d;
		printf("%lld\n",x * k);
	}
}