HDU 2138

这题用MILLER测试应该是不可避免的。

#include <iostream>
#include <cstdio>
#include <stdlib.h>
#include <time.h>
#define LL __int64
using namespace std;

LL random(LL n){
	return (LL)((double)rand()/RAND_MAX*n+0.5);
}

LL quick(LL a,LL k,LL m){
	LL ans=1;
	while(k){
		if(k&1){
			ans=ans*a%m;
		}
		k>>=1;
		a=a*a%m;
	}
	return ans;
}

bool judgep(LL p){
	for(int i=1;i<=15;i++){
		LL a=random(p-2)+1;
		if(quick(a,p,p)!=a)
		return false;
	}
	return true;
}

int main(){
	int n;
	LL p;
	srand(time(0));
	while(scanf("%d",&n)!=EOF){
		int flag=0;
		for(int i=1;i<=n;i++){
			scanf("%I64d",&p);
			if(judgep(p)){
				flag++;
			}
		}
		printf("%d
",flag);
	}
	return 0;
}