9.

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?

class Solution {
public:
    bool isPalindrome1(int x) {
        //负数和以10的倍数肯定不是对称数
        if(x<0||(x>0&&x%10==0))
            return false;
        string num = to_string(x);
        int size = num.size();
        for(int i=0;isum)
        {
            sum = sum*10+x%10;
            x = x/10;
        }
        return (x==sum)||(x==sum/10);
    }
};