快速幂模板

存档。

递归

#include<cstdio>
#include<iostream>
using namespace std;
long long n,m,p;
long long dfs(long long m)
{
	if(m==1)return n;
	if(m==2)return n%p*n%p;
	if(m==0)return 1;
	if(m%2==0)
	{
		long long g=dfs(m/2);
		return (g%p)*(g%p)%p;
	}
	if(m%2==1)
	{
		long long g=dfs(m/2);
		return (g%p)*(g%p)%p*n%p;
	}	
}
int main()
{
	cin>>n>>m>>p;
	cout<<dfs(m)%p;
}

非递归

#include<cstdio>
#include<iostream>
using namespace std;
int a,n,m;
int main()
{
	scanf("%d%d%d",&a,&n,&m);
	long long re=1ll;
	int t=a;
	while(n)
	{
		if(n&1)re=1ll*re*t%m;
		t=1ll*t*t%m;
		n>>=1;
	}
	printf("%d",re%m);
	return 0;
}