Leetcode 判断字符串是否能翻转

Example 1:

Input: 121
Output: true

Example 2:

Input: -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.

Example 3:

Input: 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

 

 

 

   function isPalindrome($x) {
         

        if($x<0){
            return false;
        }
        $yy=strrev($x);
        if($yy==$x){
            return true;
        }else{
            return false;
        }
    }