백준 1978 C++ (소수) (sqrt)

#include <iostream>
#include <string>
#include <typeinfo>
#include <algorithm>
#include <array>
#include <vector>
#include <cmath>

using namespace std;



int main() {
	int n;
	int cnt = 0;
	cin >> n;
	vector <int> v(n);
	for (int i = 0; i < n; i++) {
		int new_num;
		cin >> new_num;
		v[i] = new_num;
		if (v[i] == 2 or v[i] == 3) {
			cnt++;
		}
	}
	for (int i = 0; i < n; i++) {
		for (int j = 2; j <= sqrt(v[i]); j++) {
			if (v[i] % j == 0) {
				break;
			}
			else {
				if (j == (int)sqrt(v[i])) {
					cnt++;
				}
			}
		}
	}
	cout << cnt;
}