LeetCode | 9. Palindrome Number

题目：

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.

 

 

 

代码：

class Solution {
public:
    bool isPalindrome(int x) {
        if(x < 0)
            return false;
        long top = 1, low = 1;
        while(x / top)
        {
            top *= 10;
        }
        top /= 10;
        while(top > 1)
        {
            int left = x / top;
            int right = x % 10;
            if(left != right)
                return false;
            x %= top;
            x /= 10;
            top /= 100;
        }
        return true;
    }
};