From edcfebc814f275e7f6cac9652bf2ccc8d34cec5e Mon Sep 17 00:00:00 2001
From: bluecrow1986 <61398816+bluecrow1986@users.noreply.github.com>
Date: Thu, 15 Jul 2021 15:32:44 +0800
Subject: [PATCH] =?UTF-8?q?=E5=88=A4=E7=A9=BA=E5=A4=84=E7=90=86?=
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由于题中的Node的构造器其中无参和有一个参数的构造器中，关于List<Node> children可能会存在空，所以当List为空时encode的递归方法会存在空指针的问题；同理decode的递归也会存在本来是null的children被赋值为非null的空ArrayList
---
 src/class11/Code03_EncodeNaryTreeToBinaryTree.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/class11/Code03_EncodeNaryTreeToBinaryTree.java b/src/class11/Code03_EncodeNaryTreeToBinaryTree.java
index aa9f2ab..f8515ec 100644
--- a/src/class11/Code03_EncodeNaryTreeToBinaryTree.java
+++ b/src/class11/Code03_EncodeNaryTreeToBinaryTree.java
@@ -58,7 +58,7 @@ public class Code03_EncodeNaryTreeToBinaryTree {
 					cur.right = tNode;
 				}
 				cur = tNode;
-				cur.left = en(child.children);
+				cur.left = child.children != null ? en(child.children) : null;
 			}
 			return head;
 		}
@@ -72,7 +72,7 @@ public class Code03_EncodeNaryTreeToBinaryTree {
 		}
 
 		public List<Node> de(TreeNode root) {
-			List<Node> children = new ArrayList<>();
+			List<Node> children = root != null ? new ArrayList<>() : null;
 			while (root != null) {
 				Node cur = new Node(root.val, de(root.left));
 				children.add(cur);