Leetcode PHP题解--D73 389. Find the Difference

<?php

class Solution {

​

    /**

     * @param String $s

     * @param String $t

     * @return String

     */

    function findTheDifference($s, $t) {

        $ss = array_count_values(str_split($s));

        $tt = array_count_values(str_split($t));

        $diff = array_diff_key($tt, $ss) + array_diff($tt, $ss) + array_diff_assoc($tt, $ss);

        return key($diff);

    }

}