leetcode 9. Palindrome Number

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.

咋写都行，可递归可迭代。

class Solution {
public:
    bool isPalindrome(int x) {
        if(x<0||(x%10==0&&x!=0))return false;
        int r=0;
        while(x>r)r=10*r+x%10,x/=10;
        return x==r||x==r/10;
    }
};