最简单的试除法加上一点点范围的优化

解题思路:

注意事项:

参考代码:

import java.util.Scanner;

public class Main {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

long n = sc.nextInt();

if (isPrime(n)) {

System.out.println('Y');

}else {

System.out.println('N');

}

}

public static boolean isPrime(long i) {

for (int j = 2; j <= i / j; j++) {

if(i % j == 0)return false;

}

return true;

}

}