HDU 1576 A/B(欧几里得扩展）

#include <stdio.h>
#include <string.h>
int x,y;
int ext_eulid(int a,int b)
{
int t,d;
if(b == 0)
{
x = 1;
y = 0;
return a;
}
d = ext_eulid(b,a%b);
t = x;
x = y;
y = t - (a/b)*y;
return d;
}
int main()
{
int t,n,b,i;
scanf("%d",&t);
while(t--)
{
scanf("%d%d",&n,&b);
i = ext_eulid(b,9973);
i = (x*(n/i)%9973+9973)%9973;
printf("%d\n",i);
}
return 0;
}