快速排序

<?phpfunction quicksort(array教育部学籍在线 &$a){    $n = count($a);    quicksortinternally($a, 0, $n-1);}function quicksortinternally(array &$a, int $l, int $r){    if ($l >= $r) return;    $q = partition($a, $l, $r);    quicksortinternally($a, $l, $q-1);    quicksortinternally($a, $q+1, $r);}function partition(&$a, $l, $r): int{    $pivot = $a[$r];    $i = $l;    for ($j = $l; $j < $r; ++$j)志愿湖北 {        if ($a[$j] 北大荒的秋天课文< $pivot) {            $temp = $a[$i];            $a[$i] = $a[$j入声是第几声];            $a[$j] = $temp;            ++$i;        }    }    $temp = $a[$i];    $a[$i] = $a[$r];    $a[$r] = $temp;    return $i;}$a1 = [1,4,6,2,3,5,4];$a2 = [2, 2, 2, 2];$a3 = [4, 3, 2, 1];$a4 = [5, -1, 9, 3, 7, 8,冷漠的歌曲 3, -2, 9];quicksort($a1);print_r($a1);quicksort($a2);print_r($a2);quicksort($a3);print_r($a3);quicksort($a4);print_r($a4);