10. 整数反转

<?php
class Solution {
    /**
     * 123
     * 321
     * @param $x
     * @return false|float|int
     */
    public function reverse($x) {
        $res = 0;
        while ($x != 0) {
            $res = floor($res * 10 + $x % 10);
            $x = ($x > 0) ? floor($x / 10) : ceil($x / 10);
            if ($res > pow(2, 31) - 1 || $res < -pow(2, 31) - 1) {
                return 0;
            }
        }
        return $res;
    }
}
$cls = new Solution();
$r = $cls->reverse(1230);
print_r($r);