[백준 Java] 약수, 배수와 소수 - 2581번: 소수

 

 

import java.io.*;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int M = Integer.parseInt(br.readLine());
        int N = Integer.parseInt(br.readLine());

        int sum = 0;
        int minPrime = Integer.MAX_VALUE;

        for (int num = M; num <= N; num++) {
            boolean isPrime = true;

            if (num < 2) {
                isPrime = false;
            } else {
                for (int i = 2; i * i <= num; i++) {
                    if (num % i == 0) {
                        isPrime = false;
                        break;
                    }
                }
            }

            if (isPrime) {
                sum += num;
                minPrime = Math.min(minPrime, num);
            }
        }

        if (sum == 0) {
            bw.write("-1\n");
        } else {
            bw.write(sum + "\n" + minPrime + "\n");
        }

        br.close();
        bw.flush();
        bw.close();
    }
}