PHP内部数组指针在foreach递归函数中通过引用传递变量的问题

我正在尝试构建具有父子关系的分层关联数组。输入数据是一个元素数组。每个元素都有一个id和一个parent-id。

为了效率，当一个元素找到它的父元素时，我想从源数据中删除该子元素，这样循环就不会浪费在检查该元素是否是其他元素的子元素上。

代码如下:

// parentid == 0 indicates a root node
function buildTree(&$elements, $parentid=0){
    $branch = array();
    foreach($elements as $key => $element){
        if($element['parentid'] == $parentid){
            $twig = $element;
            unset($elements[$key]);
            $twig['children'] = buildTree($elements, $element['pageid']);
            $branch[] = $twig;
        }
    }
    return $branch;
}

我遇到的问题是，在某些情况下，一些元素永远找不到它们的父元素。

我认为这是因为$elements变量是通过引用传递的，而更深层次的递归正在破坏外部级别的内部数组指针的位置，导致其他子级被跳过，而不是在外部级别的foreach循环中被触及。

我试着看看是否有一种方法来保存内部数组指针的位置在另一个递归级别之前，然后在函数返回时恢复位置，但它似乎不可能在PHP中实现。

如果我把&拿出来，不通过引用传递$elements变量，那么函数就可以完美地工作。不幸的是，这使得元素被foreach处理，即使它们已经保存在它们适当的父元素下，也浪费了一些处理时间。

关于如何从未排序的元素池中删除子元素，他们已经被分配给他们的父元素的想法吗?

编辑:当然一些示例数据会有所帮助:

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