hdu 1576 A/B

原题链接：hdu 1576 A/B

同样是用扩展的欧几里得算法。A = 9973k+n = xB，从而转化为：xB-9973k=n求解x即可。

具体扩展欧几里得算法请参考：hdu 2669 Romantic

代码如下：

 #include <cstdio>
 #include <cstdlib>
 #include <iostream>
 #include <cstring>
 #define     MOD 9973
 using namespace std;
 typedef long long LL;
 void exgcd(LL a, LL b, LL &d, LL &x, LL&y)
 {
     if( b ==  )
     {
         d = a;
         x = ;
         y = ;
     }
     else
     {
         exgcd(b, a%b, d, x, y);
         int t = x;
         x = y;
         y = t - (a/b)*y;
     }
 }
 int main(int argc, char *argv[])
 {
     int T;
     scanf ( "%d", &T );
     int n, a, b;
     LL d, x, y;
     while( T-- )
     {
         scanf("%d%d", &n, &b);
         a = MOD;
         exgcd(a, b, d, x, y);
         y = (y%MOD)*(n/d)%MOD;
         y = (y+MOD)%MOD;
         cout<<y<<endl;
     }
 }