hdu 1576

n=A%9973即n=A-A/9973*9973,设A=B*x,B*x-9973*y=n。。exgcd解之。。。

数论题，心好累。。。

#include<cstdio>
#include<cstring>
#include<iostream>
#include<queue>
#include<algorithm>
#define inc(i,l,r) for(i=l;i<=r;i++)
#define dec(i,l,r) for(i=l;i>=r;i--)
#define mem(a) memset(a,0,sizeof(a))
#define inf 1e9
#define ll long long
#define succ(x) (1<<x)
using namespace std;
int read(){
    int x=0,f=1;char ch=getchar();
    while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();}
    while(isdigit(ch))x=x*10+ch-'0',ch=getchar();
    return x*f;
}
ll T,a,b,n,x,y;
void gcd(ll a,ll b,ll &x,ll &y){
    if(b==0){
        x=1;y=0;
    }else{
        gcd(b,a%b,y,x);
        y-=(a/b)*x;
    }
}
int main(){
    T=read();b=9973;
    while(T--){
        n=read();a=read();
        gcd(a,b,x,y);
        x*=n;
        printf("%d
",(x%b+b)%b);
    }
    return 0;
}