func_code_string: #include <bits/stdc++.h>   using namespace std;   bool check(long long x, long long y, long long p, long long q, long long t) {     return p * t >= x && q * t - p * t >= y - x;   }   int main() {     long long t;     cin >> t;     while (t--) {       long long x, y, p, q, m;       cin >> x >> y >> p >> q;       long long l = -1;       long long r = (long long)1e9;       if (!check(x, y, p, q, r)) {         printf( -1 n );         continue;       }       while (r - l > 1) {         m = l + (r - l) / 2;         if (check(x, y, p, q, m))           r = m;         else           l = m;       }       printf( %lld n , r * q - y);     }     return 0;   }   