帮我写个递归

Question

数据库表test
id  name  pid
1   a      0
2   b      1
3   c      1
4   d      2
5   e      2
6   f      3
7   g      4pid是父ID，即取id值
然后要输出一个树：
a
|-b
  |-d
    |-g
  |-e
|-c
  |-f不好意思，数据结构不会，算法不行...

Answer 1

//数据集
$result[0] = array('id'=>1,'pid'=>0,'name'=>'a',);
$result[1] = array('id'=>2,'pid'=>1,'name'=>'b');
$result[2] = array('id'=>3,'pid'=>1,'name'=>'c');
$result[3] = array('id'=>4,'pid'=>2,'name'=>'d');
$result[4] = array('id'=>5,'pid'=>2,'name'=>'e');
$result[5] = array('id'=>6,'pid'=>3,'name'=>'f');
$result[6] = array('id'=>7,'pid'=>4,'name'=>'g');
//简易类
class tree
{
    function tree($rs,$idName,$pidName,$nodeName)
    {
        $this->idName = $idName;
$this->nodeName = $nodeName;

$tree = array();
foreach((array)$rs as $k=>$v)
{
$tree[$v[$pidName]][] = $v;
} $this->treeArray = $tree;

}
    function showTree($root,$deep)
    {
        if( $this->treeArray[$root] )
        {
            foreach($this->treeArray[$root] as $k=>$v)
            {
                $t = $v[$this->idName];
//view
                $str = str_repeat(" ",$deep*2)."|-";
                $html[] ="{$str}{$v[$this->nodeName]}";    
                if($this->treeArray[$t] ) 
                {
                    $dp    = $deep + 1;
                    $html[]= $this->showTree( $t,$dp );
                }
            }
        }
        return implode("<br/>",$html);
    }
}
$tree = new tree($result,'id','pid','name');
echo $tree->showTree(0,0);

Answer 2

数据量有多少?
你就整个copy这段代码过去会死循环?