AC代码：

#include 
     
      #include 
      
       using namespace std;int mod_exp(long long a,long long b,int m){    int temp=1;    a=a%m;    while(b)    {        if(b%2==1)            temp=temp*a%m;        a=a*a%m;        b>>=1;    }        return temp;}int main(void){    freopen("in.txt","r",stdin);    long long T;    scanf("%lld",&T);    while(T--)    {        long long n;        int temp,m=10;        scanf("%lld",&n);        temp=mod_exp(n,n,m);                printf("%d\n",temp);    }    fclose(stdin);    return 0;}