无限极子孙分类统计某个用户的层级子孙各有哪些 各有多少

<?php
$tree=array(
array("id"=>"1",  "name"=>"用户1" ,  "father_id"=>"0"),
array("id"=>"2",  "name"=>"用户2" ,  "father_id"=>"1"),
array("id"=>"3",  "name"=>"用户3" ,  "father_id"=>"2"),
array("id"=>"4",  "name"=>"用户4" ,  "father_id"=>"3"),
array("id"=>"5",  "name"=>"用户5" ,  "father_id"=>"1"),
array("id"=>"6",  "name"=>"用户6" ,  "father_id"=>"5"),
array("id"=>"7",  "name"=>"用户7" ,  "father_id"=>"6"),
array("id"=>"8",  "name"=>"用户8" ,  "father_id"=>"3"),
array("id"=>"9",  "name"=>"用户9" ,  "father_id"=>"4"),
array("id"=>"10", "name"=>"用户10" , "father_id"=>"5"),
array("id"=>"11", "name"=>"用户11" , "father_id"=>"6"),
array("id"=>"12", "name"=>"用户12" , "father_id"=>"7"),
array("id"=>"13", "name"=>"用户13" , "father_id"=>"2"),
array("id"=>"14", "name"=>"用户14" , "father_id"=>"13"),
array("id"=>"15", "name"=>"用户15" , "father_id"=>"2"),
array("id"=>"16", "name"=>"用户16" , "father_id"=>"17"),
array("id"=>"17", "name"=>"用户17" , "father_id"=>"5"),
array("id"=>"18", "name"=>"用户18" , "father_id"=>"17"),
array("id"=>"19", "name"=>"用户19" , "father_id"=>"18"),
array("id"=>"20", "name"=>"用户20" , "father_id"=>"20"),
array("id"=>"21", "name"=>"用户21" , "father_id"=>"3"),
array("id"=>"22", "name"=>"用户22" , "father_id"=>"21"),
array("id"=>"23", "name"=>"用户23" , "father_id"=>"6"),
array("id"=>"24", "name"=>"用户24" , "father_id"=>"23"),
array("id"=>"25", "name"=>"用户25" , "father_id"=>"9"),
);

foreach ($tree as $key => $value)
{
$user_list[$value['id']]=$value['name'];
$father_link[$value['father_id']][]=$value['id'];
}

function get_level_son($father_link=array(),$user_id=0,$level=1)
{
$father_list=array($user_id);
for ($i=0; $i < $level; $i++)
{
$tmp_father=array();
foreach ($father_list as $key => $v)
{
if(isset($father_link[$v]))
{
$tmp_father=array_unique(array_merge($tmp_father,$father_link[$v]));//找子孙
}
}
$father_list=$tmp_father;//将子孙赋值给父亲
}
return $father_list;
}
echo '<link href="https://cdn.bootcss.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" rel="stylesheet">';
echo "<div class='container'><table class='table table-striped table-bordered table-hover table-condensed' style='width:80%;'>
<thead><tr><td>用户</td><td>1级子孙数量</td><td>1级子孙</td><td>2级子孙数量</td><td>2级子孙</td><td>3级子孙数量</td><td>3级子孙</td></tr></thead>";
echo "<tbody>";
foreach ($user_list as $key => $v)
{
$list1=get_level_son($father_link,$key,1);
$list2=get_level_son($father_link,$key,2);
$list3=get_level_son($father_link,$key,3);
$count1=count($list1);
$count2=count($list2);
$count3=count($list3);
echo "<tr>
<td>".$v."</td>
<td>".$count1."</td>
<td>".implode(",",$list1)."</td>
<td>".$count2."</td>
<td>".implode(",",$list2)."</td>
<td>".$count3."</td>
<td>".implode(",",$list3)."</td>
</tr>";
}
echo "</tbody></table></div>";
?>