9. Palindrome Number

 1 class Solution {
 2 public:
 3     bool isPalindrome(int x) {
 4         int left = 1;
 5         int right = 10;
 6         int temp = x;
 7         while (temp >= 10) {
 8             left *= 10;
 9             temp /= 10;
10         }
11         if (x < 0) return false;
12         if (left == 1) return true;
13         else {
14             if (left == 10) return x / 10 == x % 10;
15             while (left >= right) {
16                 int a = x / left % 10; 
17                 int b = x % right / (right / 10);
18                 if (a != b) return false;
19                 left /= 10;
20                 right *= 10;
21             }
22             return true;
23         }
24     }
25 };