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));
?>