php可应用于面包屑导航的迭代寻找家谱树实现方法

<?php
echo "<pre>";
$area = array(
array('id'=>1,'area'=>'北京','pid'=>0),
array('id'=>2,'area'=>'广西','pid'=>0),
array('id'=>3,'area'=>'广东','pid'=>0),
array('id'=>4,'area'=>'福建','pid'=>0),
array('id'=>11,'area'=>'朝阳区','pid'=>1),
array('id'=>12,'area'=>'海淀区','pid'=>1),
array('id'=>21,'area'=>'南宁市','pid'=>2),
array('id'=>45,'area'=>'福州市','pid'=>4),
array('id'=>113,'area'=>'亚运村','pid'=>11),
array('id'=>115,'area'=>'奥运村','pid'=>11),
array('id'=>234,'area'=>'武鸣县','pid'=>21)
); 

function familytree($arr,$id){
 $list = array();
 while($id){
 $flag = false;
 foreach($arr as $v){
  if($v['id']==$id){
  array_unshift($list,$v['area']);
  $id = $v['pid'];
  $flag = true;
  }
 }
 if(!$flag){
  break;
 }
 }
 return $list;
}
print_r(familytree($area,113));
?>