백준[JAVA] 1978.소수 찾기 - 자바

📖 문제

📃 코드

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    static boolean isPrime(int num) {
        boolean check = true;
        if (num == 1) {
            check = false;
        } else {
            for (int i = 2; i <= Math.sqrt(num); i++) {
                if (num % i == 0) {
                    check = false;
                    break;
                }
            }
        }
        return check;
    }

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;
        int cnt = 0;
        int N = Integer.parseInt(br.readLine());

        st = new StringTokenizer(br.readLine(), " ");

        while (st.hasMoreTokens()) {
            int num = Integer.parseInt(st.nextToken());
            if(isPrime(num)){
                cnt++;
            }
        }

        System.out.println(cnt);
    }
}

🔗 링크

https://www.acmicpc.net/problem/1978

1978번: 소수 찾기