初学6N±1判定素数

import java.util.Scanner;public class Main {public static boolean prime(int k) {if ((k - 1) % 6 == 0 || (k + 1) % 6 == 0)return true;return false;}public static boolean isprime(int k) {int flag = 0;for (int i = 2; i <= Math.sqrt(k); i++) {if (k % i == 0) {flag++;break;}}if (flag == 0)return true;return false;}@SuppressWarnings("resource")public static void main(String[] args) {Scanner sc = new Scanner(System.in);while (sc.hasNext()) {int n = sc.nextInt();if (n == 1) {System.out.println("no");} else if (n == 2 || n == 3 || n == 5) {System.out.println("yes");} else {if (prime(n)) {if (isprime(n)) {System.out.println("yes");} else {System.out.println("no");}} else {System.out.println("no");}}}}}