看了版主的无限分类，分成树形结构后，怎么还原

父子无限分类

原始数组
/*
获取无线分类，对无线分类进行节点路径排列
*/
$a=array (
  0 =>
  array (
    'id' => '134',
    'fid' => '0',
    'name' => 't',
  ),
  1 =>
  array (
    'id' => '133',
    'fid' => '0',
    'name' => 'k',
  ),
  2 =>
  array (
    'id' => '132',
    'fid' => '0',
    'name' => 'j',
  ),
  3 =>
  array (
    'id' => '137',
    'fid' => '133',
    'name' => '我是k的分类1',
  ),
  4 =>
  array (
    'id' => '136',
    'fid' => '134',
    'name' => '我是t的分类t2',
  ),
  5 =>
  array (
    'id' => '135',
    'fid' => '134',
    'name' => '我是t的分类t1',
  ),
  6 =>
  array (
    'id' => '138',
    'fid' => '137',
    'name' => '我是k的分类1-1',
  ),
  7 =>
  array (
    'id' => '139',
    'fid' => '138',
    'name' => '我是k的分类1-1-1',
  ),
  8 =>
  array (
    'id' => '140',
    'fid' => '139',
    'name' => '我是k的分类1-1-1-1',
  ),
)
?>

开始形成树，并且增加路径，树形数组为$trees
Array
(
    [0] => Array
        (
            [id] => 134
            [fid] => 0
            [name] => t
            [path] => 134
            [_sub] => Array
                (
                    [0] => Array
                        (
                            [id] => 136
                            [fid] => 134
                            [name] => 我是t的分类t2
                            [path] => 134,136
                        )

                    [1] => Array
                        (
                            [id] => 135
                            [fid] => 134
                            [name] => 我是t的分类t1
                            [path] => 134,135
                        )

                )

        )

    [1] => Array
        (