hdu 1576 擴充歐幾裡得

#include<cstdio>#include<iostream>#include<algorithm>typedef __int64 LL;const LL mod = 9973;using namespace std;LL gcd(LL a,LL b){    return b==0?a:gcd(b,a%b);}void gcd(LL a,LL b,LL& d,LL& x,LL& y){    if(!b)    {        d=a;        x=1;        y=0;    }    else    {        gcd(b,a%b,d,y,x);        y-=x*(a/b);    }}int main(){    LL b,n;    int t;    scanf("%d",&t);    while(t--)    {        scanf("%I64d%I64d",&n,&b);        LL x=0,y=0;        LL d=1;        gcd(b,mod,d,x,y);        while(x<0||y>0)        {            x+=mod;            y-=b;        }        //printf("%I64d\n",x);        printf("%I64d\n",(n*x)%mod);    }    return 0;}