Prime Palindromes 回文质数 Java

判断回文数可以参考LeetCode 9，注意跳过所有偶数情况，可以节省时间。
LeetCode 9.判断回文数

public class Solution {
    
        
	   public static void main(String[] args) {
    
    
	        // TODO Auto-generated method stub
	       Scanner sc = new Scanner(System.in);
	       int a = sc.nextInt();
	       int b = sc.nextInt(); 
	       
		   for(int i = a;i<=b;i++){
    
    
	            if(i%2!=0&& isPalindrome(i)&&isPrimeNumber(i) ){
    
    
	                System.out.println(i);
	            }
	        }	 
	    }

	    private static boolean isPrimeNumber(int num) {
    
    
	        if (num<2 || num %2 ==0){
    
    
	            return false;
	        }
	        for (int i = 2; i <= Math.sqrt(num); i++) {
    
    
	            if (num %i == 0){
    
    
	                return false;
	            }
	        }
	        return true;
	    }

	    private static boolean isPalindrome(int num) {
    
    
	        String numString = num+"";
	        int low = 0;
	        int high = numString.length()-1;
	        while (low < high){
    
    
	            if (numString.charAt(low) != numString.charAt(high)){
    
    
	                return false;
	            }
	            low++;
	            high--;  
	        }
	        return true;
	    }
}