HDU_1061:Rightmost Digit

#include<stdio.h>
int main(void)
{
    int cases, n, copy_n, result;
    scanf("%d", &cases);
    while(cases--)
    {
        scanf("%d", &n);
        copy_n = n;
        n = n%10;
        result = 1;
        while(copy_n--)
        {
            result = (result*n)%10;
        }
        printf("%d\n", result);
    }
    
    return 0;
}

下面，快速幂一来就AC了：

#include<stdio.h>
int my_power(int m, int n); // 求m的n次方的尾数
int main(void)
{
    int cases, n;
    scanf("%d", &cases);
    while(cases--)
    {
        scanf("%d", &n);
        printf("%d\n", my_power(n, n));
    }
    
    return 0;
}

int my_power(int m, int n)
{
    m = m%10;
    if(n == 1)
        return m;
    if(n%2 == 0)
        return ( my_power(m*m, n/2) ) % 10;
    else
        return ( my_power(m*m, n/2)*m ) % 10;
}