【分治】取余运算

#include <iostream>
#include <cstdio>
#include <cmath>

using namespace std;

//a*b % n = (a % n)*(b % n) % n
long int mod_fenzhi(long int b,long int p,long int k){
    if(p==1){
        return b%k;
    }
    if(p==2){
        return b*b%k;
    }
    if(p%2==0){
        long int aa=mod_fenzhi(b,p/2,k);
        return aa*aa%k;
    }
    if(p%2==1){
        long int aa=mod_fenzhi(b,p/2,k);
        return aa*aa*b%k;
    }
}

int main()
{
    long int b;
    long int p;
    long int k;
    long int jieguo;
    while(scanf("%ld %ld %ld",&b,&p,&k)!=EOF){
        jieguo=mod_fenzhi(b,p,k);
        printf("%ld^%ld mod %ld=%ld\n",b,p,k,jieguo);
    }
    return 0;
}