1 Description（描述）
Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.
确定一个数是否是回文数。一个数从前读从后读都是相同的，那么这个数是回文数。
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.
解释：从左到右，他是-121。从右到左，他是121-。因此他不是回文数。
Example 3:
Input: 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
解释：从右到左为01。因此他不是回文数。
注：小数，负数没有回文数。
Follow up:
Could you solve it without converting the integer to a string?
你能不将整型数转化为字符串解决问题么？
注：问题其实就转换成Reverse Integer问题，只不过就是看Reverse Integer是否等于原数。
class Solution {public boolean isPalindrome(int x) {if(x < 0) return false;int input = x;int rev = 0;while (x != 0) {rev = rev * 10 + x % 10;x /= 10;}return rev == input;}
}
注：内容均来源于leetcode。