Palindrome Number

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

boolean isPalindrome(int x) {
    if (x < 0) return false;
    int div = 1;

    while (x / div >= 10) {
        div *= 10;
    }

    while (x != 0) {
        int l = x / div;
        int r = x % 10;
        if (l != r) return false;
        x = (x % div) / 10;//去掉x的第一位和最后一位
        div /= 100;
    }
    return true;
}