LeetCode OJ 9. Palindrome Number

题目：判断整型数字是否为回文数字。例如123454321，6756576

如下规律可以优化时间复杂度。

package edu.jnu;public class Main {    public static void main(String[] args) {// write your code here        Main m = new Main();        System.out.println(m.isPalindrome(123));    }    public boolean isPalindrome(int x) {        //优化处理        if(x < 0) return false;        if(x < 10) return true;        if(x % 10 == 0) return false;        double xx = Math.sqrt(x);        if(xx == 11.0 || xx == 111.0 || xx == 1111.0 || xx == 11111.0)            return true;        int temp = x;        //数字翻转        int xReverse = 0;        while (temp != 0){            xReverse = xReverse*10 + temp%10;            temp /= 10;        }        return x == xReverse;    }}