P1226 24分求调

#include<bits/stdc++.h>
using namespace std;
unsigned long long a,b,k;
unsigned long long qm(unsigned long long a,unsigned long long b){
    unsigned long long ans=1,x=a%k,t=b;
	while(t){
		if(t%2!=0){
			ans*=x;
            ans=ans%k;
		}
		x*=x%k;
		t/=2;
	}
	return ans;
}
int main(){
	cin>>a>>b>>k;
    unsigned long long s=qm(a,b); 
	cout<<a<<"^"<<b<<" mod "<<k<<"="<<s;
	return 0;
}