PHP implements quick sort method function code

Code 1:
Copy code The code is as follows:
function quicksort($str){
if(count($str)<=1) return $str;//If the number is not greater than one, directly Return
$key=$str[0];//Get a value to compare later;
$left_arr=array();
$right_arr=array();
for($i=1;$i< count($str);$i++){//The ones larger than $key are placed on the right, and the smaller ones are placed on the left;
if($str[$i]<=$key)
$left_arr[]=$str [$i];
else
$right_arr[]=$str[$i];
}
$left_arr=quicksort($left_arr);//Perform recursion;
$right_arr=quicksort($right_arr);
return array_merge ($left_arr,array($key),$right_arr);//Merge the left, middle and right values ​​into an array;
}//The following is the test
$str=array(5,3,8,2,5, 9,7,2,1,4,0);
print_r(quicksort($str));
?>

Code 2:
Copy code The code is as follows:
/* @quicksort*/
function quickSort ($left,$right,$arr){
$l = $left;
$r = $right;
$pivot = $arr[($left+$right)/2];
$temp = 0;

while($l<$r){
while($arr[$l]<$pivot){
$l++;
}
while($arr[$r]>$pivot){
$r-- ;
}

if($l>=$r) break;

$temp = $arr[$l];
$arr[$l] = $arr[$r];
$arr[$r] = $temp;

if($arr[$l]==$pivot) --$r;
if($arr[$r]==$pivot) ++$l;
}

if($ l==$r){
$l++;
$r--;
}

if($left<$r){
quickSort($left, $r, $arr);
}elseif($right> $l){
quickSort($l, $right, $arr);
}else{
return $arr;
}
}