fzu 1402 中国剩余定理 http://acm.fzu.edu.cn/problem.php?pid=1402

//两两互质。
#include<stdio.h>
#include<string.h>
#define in __int64
in num1[15];
in num2[15];
in ext_Euclid(in a,in b,in &x,in &y)
{
if(b==0)
{
x=1;
y=0;
return a;
}
in d=ext_Euclid(b,a%b,x,y);
in tem=x;
x=y;
y=tem-a/b*y;
return d;
}
in China_Reminder(int len,in* n,in* a)
{
in result=0;
in N=1;
int i,j;
for(i=0; i<len; i++)
N=N*n[i];
for(j=0; j<len; j++)
{
in m=N/n[j];
in x,y;
ext_Euclid(m,n[j],x,y);
//   printf("x=%I64d\n",x);
x=(x%n[j]+n[j])%n[j];
result = (result + m*a[j]*x%N)%N;
}
return result;
}
int main()
{
int n;
while(scanf("%d",&n)!=EOF)
{
for(int i=0; i<n; i++)
{
scanf("%I64d%I64d",&num1[i],&num2[i]);
}
printf("%I64d\n",China_Reminder(n,num1,num2));
}
return 0;
}