快速幂取模

#include <iostream>
#include <stdio.h>
#include <math.h>
using namespace std;

//计算 m^n % k, 快速幂取模
long getMi(long m,long n,long k){
	long t = 1;
	int tmp = m;
	while(n){
		if( n & 1) t = t * tmp % k;
		tmp = tmp * tmp % k;
		n >>= 1;
	}
	return t;
}

int main() {
	 int a,b;

	 //计算 a^b
	 scanf("%d%d",&a,&b);
	 int count = 0, ans, tpans;
	 ans = 1;
	 tpans = a;
	 while(b){
		 ++count; //统计次数
		 if(b & 1) ans *= tpans; //如果b的最后一位为1
		 tpans = tpans * tpans;
		 b >>= 1; //b每次像右移一位，相当于除2

	 }
	 printf("Count=%d\n a^b=%d\n",count,ans);

	 cout << "3^4 % 5= " << getMi(3,4,5) << endl;
	 cout << "3^4 % 5= " << (int)pow(3,4) % 5 << endl;;
	return 0;
}