对应L13-7，只是稍作变化

#include<iostream>
#include<cstdio>
using namespace std;
int main(){
    long long a,b,p,ans=1;
    scanf("%lld%lld%lld",&a,&b,&p);
    printf("%lld^%lld mod %lld=",a,b,p);
    while(b){
        if(b%2==1)
            ans=(ans*a)%p;
        b/=2;
        a=(a*a)%p;
    }
    printf("%lld",ans);
    return 0;
}