一个素数的问题，但是求的是素数的个数，怎么利用C语言的办法解决的

Question

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

Answer 1

可以暴力解决，对于每一个数从2开始除道sqrt(N),检查是否为素数，复杂度O（n^1.5)

要么维护一个素数表，可以每次查询，复杂度O（n),素数表可以先找到最大的值再构造。