请教用 Java 如何写一个用来将 leetcode 给出的[4,1,null,2,null,3]这种形式的树，转换为一颗真的树的根节点的函数？

给出一个我的实现，目前用了几个都对~

 public static TreeNode build(Integer[] vals) { int valid_vals_size = vals.length; Queue<TreeNode> queue = new LinkedList<>(); LinkedList<Integer> level_order_traveresal = new LinkedList<>(Arrays.asList(vals)); TreeNode root = new TreeNode(vals[0]); queue.add(root); valid_vals_size--; int index = 0; while (true) { TreeNode poll = queue.poll(); int left_index = 2 * index + 1; int right_index = 2 * index + 2; if (poll == null) { level_order_traveresal.add(left_index, null); level_order_traveresal.add(right_index, null); } else { if (left_index >= level_order_traveresal.size()) { break; } Integer left_node = level_order_traveresal.get(left_index); if (left_node != null) { poll.left = new TreeNode(left_node); valid_vals_size--; } queue.add(poll.left); if (right_index >= level_order_traveresal.size()) break; Integer right_node = level_order_traveresal.get(right_index); if (right_node != null) { poll.right = new TreeNode(right_node); valid_vals_size--; } queue.add(poll.right); } index++; if (valid_vals_size <= 0) break; } return root; }