用PHP编写递归排序算法：快速排序和归并排序

快速排序算法的PHP实现：

function quickSort($arr){    $length = count($arr);        if($length <= 1){        return $arr;    }        $pivot = $arr[0];    $left = [];    $right = [];        for($i=1; $i<$length; $i++){        if($arr[$i] < $pivot){            $left[] = $arr[$i];        }else{            $right[] = $arr[$i];        }    }        return array_merge(quickSort($left), [$pivot], quickSort($right));}$arr = [3, 6, 8, 10, 1, 2, 1];$sortedArr = quickSort($arr);print_r($sortedArr);

归并排序算法的PHP实现：

function mergeSort($arr){    $length = count($arr);        if($length <= 1){        return $arr;    }        $mid = (int)($length / 2);        $left = array_slice($arr, 0, $mid);    $right = array_slice($arr, $mid);        $left = mergeSort($left);    $right = mergeSort($right);        return merge($left, $right);}function merge($left, $right){    $result = [];        while(count($left) > 0 && count($right) > 0){        if($left[0] < $right[0]){            array_push($result, array_shift($left));        }else{            array_push($result, array_shift($right));        }    }        while(count($left) > 0){        array_push($result, array_shift($left));    }        while(count($right) > 0){        array_push($result, array_shift($right));    }        return $result;}$arr = [3, 6, 8, 10, 1, 2, 1];$sortedArr = mergeSort($arr);print_r($sortedArr);