function str_split_unicode($str) {
$tmp = preg_split("//u", $str, -1, PREG_SPLIT_NO_EMPTY);
return $tmp;
}

function str_shuffle_unicode($str) {
$tmp = preg_split("//u", $str, -1, PREG_SPLIT_NO_EMPTY);
shuffle($tmp);
return join("", $tmp);
}

Xịn