程序代码：

#include <stdio.h>

int cal(int a, int b)
{
    int r;
    if(b == 0) return 1;
    return (r = cal(a, b >> 1)) * r * (b & 1 ? a : 1) % 1000;
}

int main()
{
    int n, a, b;
    for(scanf("%d", &n); n-- && scanf("%d%d", &a, &b); printf("%d\n", cal(a, b)));
    return 0;
}