HDU 2138 How many prime numbers

How many prime numbers

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 7017    Accepted Submission(s): 2336

Problem Description

  Give you a lot of positive integers, just to find out how many prime numbers there are.

 

Input

  There are a lot of cases. In each case, there is an integer N representing the number of integers to find. Each integer won’t exceed 32-bit signed integer, and each of them won’t be less than 2.

 

Output

  For each case, print the number of prime numbers you have found out.

 

Sample Input

3 2 3 4

 

Sample Output

2

 

题意：这题和纠结，就是求是不是素数。打表竟然超时。这题水的很坚强啊！

AC代码：

#include
#include
using namespace std;
#define N 100000000
int main()
{
	int n,b,s,f,i;
	while(scanf("%d",&n)!=EOF)
	{
        s=0;
		while(n--)
		{
			scanf("%d",&b);
			f=0;
			for(i=2;i<=sqrt(b*1.0);i++)
				if(b%i==0)
				{f=1;break;}
				if(!f)s++;
		}
		printf("%d\n",s);
	}
	return 0;
}