6. 回文数

<?php
class Solution {
    /**
     * 121 true
     * -121 false
     * 10 false
     * @param $x
     * @return bool
     */
    public function isPalindrome($x) {
        if ($x < 0 || ($x != 0 && $x %10 == 0)) return false;
        $source = $x;
        $rev = 0;
        while($x != 0) {
            $rev = $rev * 10 + $x % 10;
            $x = floor($x / 10);
        }
        return $source == $rev;
    }
}