Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.

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.

Follow up:

Coud you solve it without converting the integer to a string?

還是回文的問題，這題沒有給出數字的區間，不過我們不用擔心，回文數正反一樣所以反過來也不會溢出的，我們可以利用之前的整數翻轉的方法,如果回文reverse之後肯定相等

另外根據題意負數肯定是不回文的

class Solution {
    
 
public boolean isPalindrome(int x) {
        if(x<0) return false;
        if(x!=reverse(x)) return false;
        return true;
    }
    
    public int reverse(int x) {
        int res = 0,tag=0;
        while (x != 0) {
            tag = res * 10 + x % 10;
            if (tag / 10 != res) return 0;
            res 
 
= tag;
            x = x / 10;
        }
        return res;
    }
}

[LeetCode]9. Palindrome Number回文數