Quick sort recursive version php implementation

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Start reviewing the algorithm today, even the most familiar I can’t even write out the quick queue, I’m so embarrassed, I’ll post the code for future reference

function qSort(array &$a, $low, $high)
{   
    if($low >= $high) {
        return;
    }
    $index = partition($a,$low,$high);
    qSort($a,$low,$index-1);
    qSort($a,$index+1,$high);
}

//元素相互赋值比交换效率
function partition(array &$a, $low, $high)
{
    $temp = $a[$low];
    while($low < $high) {
        while($low < $high && $a[$high] >= $temp) { 
            --$high;
        }   
        $a[$low] = $a[$high];
        while($low < $high && $a[$low] <= $temp) {
            ++$low;
        }   
        $a[$high] = $a[$low];
    }   
    $a[$low] = $temp;
    return $low;
}

$a = [0,20,7,-1,6,2,6,2,8, 9,0,1];
qSort($a, 0, count($a) -1);

var_dump(implode(',', $a));

Result display: -1,0,0,1,2,2,6,6,7,8,9,20

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