LeetCode-Palindrome Number

##题目

####Palindrome Number

Determine whether an integer is a palindrome. Do this without extra space.

####Some hints:
Could negative integers be palindromes? (ie, -1)

If you are thinking of converting the integer to string, note the restriction of using extra space.

You could also try reversing an integer. However, if you have solved the problem “Reverse Integer”, you know that the reversed integer might overflow. How would you handle such case?

There is a more generic way of solving this problem.

##解题思路
该题是判断一个整数是不是回文数，即整数逆序翻转之后与原数相同。整数的翻转可以借鉴LeetCode-Reverse Integer中的方法。这里有一个情况需要考虑，如果整数为负数，则该整数不是回文数。

##算法代码
代码采用JAVA实现：

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public class Solution {
    public boolean isPalindrome(int x) {
        if(x<0) return false;//负数不是回文
        if(x==0) return true;
        //对数值进行翻转，回文翻转之后还等于原来的数
        int reverseNum=0;
        int num=x;
        while(num>0)
        {
        	int modnum=num%10;
        	//考虑翻转会溢出的情况
        	if((reverseNum>Integer.MAX_VALUE/10)||((reverseNum==Integer.MAX_VALUE/10)&&(modnum>Integer.MAX_VALUE%10)))
        		return false;
        	reverseNum=reverseNum*10+modnum;
        	num=num/10;
        }
        if(reverseNum==x)
        	return true;
        else
        	return false;
    }
}