Determine whether an integer is a palindrome. Do this without extra space.
def isPalindrome(x: Int): Boolean = {
if (x < 0 || (x != 0 && x % 10 == 0)) false
else {
var _x = x
var res = 0
while (x > res) {
res = res * 10 + _x % 10
_x /= 10
}
x == res || x == res / 10
}
}
