hdu 1576 A/B

 1 #include <cstdio>
 2 #include <cstdlib>
 3 #include <iostream>
 4 #include <cstring>
 5 using namespace std;
 6 typedef long long LL;
 7 void exgcd(LL a, LL b, LL &d, LL &x, LL&y)
 8 {
 9     if( b == 0 )
10     {
11         d = a;
12         x = 1;
13         y = 0;
14     }
15     else
16     {
17         exgcd(b, a%b, d, x, y);
18         int t = x;
19         x = y;
20         y = t - (a/b)*y;
21     }
22 }
23 int main(int argc, char *argv[])
24 {
25     int T;
26     scanf ( "%d", &T );
27     int n, a, b;
28     LL d, x, y;
29     while( T-- )
30     {
31         scanf("%d%d", &n, &b);   
32         a = 9973;
33         exgcd(a, b, d, x, y);
34         y = (y%9973)*(n/d);
35         y %= 9973;
36         if( y < 0 )
37         {
38             y += 9973;
39         }
40         cout<<y<<endl;
41     }
42 }