PHP 實現無極限分類

資料庫有以下商品分類

用你覺得最優的演算法將以上記錄按以下格式輸出:

1.從資料庫裡面查出所有的資料,整理後格式如下:

$cat = [
	['id'=>1,'parentId'
 
=>0,'name'=>'水果'],
	['id'=>2,'parentId'=>0,'name'=>'奶粉'],
	['id'=>3,'parentId'=>1,'name'=>'蘋果'],
	['id'=>4,'parentId'=>3,'name'=>'青蘋果'],
	['id'=>5,'parentId'=>3,'name'=>'紅蘋果'],
	['id'=>6,'parentId'=>2,'name'=>'進口奶粉'],
	['id'=>7,'parentId'=>6,'name'
 
=>'澳洲進口奶粉'],
	['id'=>8,'parentId'=>0,'name'=>'3c數碼'],
];

2.重新調整資料結構

/**
 * @param $cat 
 * @param int $parentId
 * @param array $list
 * @param int $i 
 * @return array
 */
function getCatTree($cat,$parentId=0,&$list=[],$i=0){
	foreach ($cat as $k => $v) {
		if($v['parentId'] == $parentId
 
){
			$v['name'] = line($i,$v['name']);
			unset($v['parentId']);
			$list[] = $v;
			unset($cat[$k]);
			getCatTree($cat,$v['id'],$list,$i+1);
		}
		continue;
	}

	return $list;
}

/**
 * @param $i
 * @param $name
 * @return string
 */
function line($i,$name){
	$line = '';
	for($j=0;$j<$i;$j++){
		$line .= '--';
	}
	return $line.$name;
}

3.呼叫寫好的函式

$list = getCatTree($cat);
print_r($list); 
//輸出結果如下:
Array
(
    [0] => Array
        (
            [id] => 1
            [name] => 水果
        )

    [1] => Array
        (
            [id] => 3
            [name] => --蘋果
        )

    [2] => Array
        (
            [id] => 4
            [name] => ----青蘋果
        )

    [3] => Array
        (
            [id] => 5
            [name] => ----紅蘋果
        )

    [4] => Array
        (
            [id] => 2
            [name] => 奶粉
        )

    [5] => Array
        (
            [id] => 6
            [name] => --進口奶粉
        )

    [6] => Array
        (
            [id] => 7
            [name] => ----澳洲進口奶粉
        )

    [7] => Array
        (
            [id] => 8
            [name] => 3c數碼
        )

)