HDU 2.1.2 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): 8122 Accepted Submission(s): 2619

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

 

OJ上用pow(x,0.5)會導致complier error

sqrt需要把參數轉換爲double，不然也會出錯

菜鳥級的原創代碼，已AC。若有可提高之處歡迎指導

#include<stdio.h>
#include<math.h>
bool isPrime(int x)
{
	if (x == 2)return true;
	int i = sqrt((double)x)+1;
	while (--i>1)
	if (x%i == 0)return false;
	return true;
}
int main()
{
	int n,total,temp;
	while (scanf("%d", &n) == 1)
	{
		total = 0;
		while (n--)
		{
			scanf("%d", &temp);
			if (isPrime(temp))
				total++;
		}
		printf("%d\n", total); 
	}
	return 0;
}