Palindrome Number

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

public class Solution {    public bool IsPalindrome(int x) {        if (x == int.MaxValue || x == int.MinValue || x<0)            return false;        if (x < 10)            return true;        x = x > 0 ? x : -x;        long tmp = x, highIdx = 1, lowIdx = 1;        while (tmp > 0)        {            highIdx *= 10;            tmp /= 10;        }        //Be careful        highIdx /= 10;        while (highIdx >= lowIdx)        {            var high = x / highIdx % 10;            var low = x / lowIdx % 10;            if (high != low)            {                return false;            }            highIdx /= 10;            lowIdx *= 10;        }        return true;    }}