LightOJ 1077 Solution

 #include<bits/stdc++.h>

#define ll long long int

using namespace std;

ll gcd(ll a, ll b)

{

if(b == 0)

return a;

return gcd(b, a%b);

}

int main()

{

int t, i = 1;

cin >> t;

while(t--)

{

ll x1, y1, x2, y2;

cin >> x1 >> y1 >> x2 >> y2;

ll r1 = abs(x1-x2), r2 = abs(y1-y2);

cout << "Case " << i++ << ": " << gcd(r1, r2)+1 << "\n";

}

return 0;

}