SPOJ - The last digit

https://vjudge.net/problem/SPOJ-LASTDIG

求最后一位，%10就完了

这个题居然要求代码小于等于700B

#include <iostream>
#include <cstdio>
#define p(a) putchar(a)
#define For(i,a,b) for(long long i=a;i<=b;++i)

using namespace std;
long long T,n,x,y;

long long ksm(long long a,long long b){
    long long r=1;
    while(b>0){
        if(b&1)
            r=r*a%10;
        a=a*a%10;
        b>>=1;
    }
    return r;
}

int main(){
    cin>>T;
    while(T--){
        cin>>x>>y;
        cout<<ksm(x,y);p('\n');
    }
    return 0;
}