HDU 1576 扩展欧几里得

/*    题目大意：    简单的中文数学题.//题目中给出B与9973互质，可以直接套用小费马//而我采用扩展的欧几里得算法解*/#include<iostream>#include<cmath>#include<cstring>#include<string>#include<iomanip>#define MO 9973using namespace std;void ext_gcd(int a,int b,int &x,int &y){    int t;    if (b==0) { x=1; y=0; return; }    else { ext_gcd(b,a%b,x,y); t=x; x=y; y=t-(a/b)*y;}    return;}int main(){    int T;cin>>T;while(T--){    int n,B,x,y;scanf("%d%d",&n,&B);        ext_gcd(B,MO,x,y);x=(x+MO)%MO;int res=(x*n)%MO;cout<<res<<endl;}    return 0;}