Palindrome Number

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

思路：反向计算出来值，然后跟原来的值比较就可以了。注意：保存原来的值；

public class Solution {
public boolean isPalindrome(int x) {
if(x < 0) return false;
int original = x;
int sum = 0;
while(x!=0) {
int last = x%10;
sum = sum*10 + last;
x = x/10;
}
return original == sum ;
}
}