From 2c584ce661768c35ac4e16f5af0cbbbf339b4bf4 Mon Sep 17 00:00:00 2001
From: ironartisan <54694467+ironartisan@users.noreply.github.com>
Date: Mon, 6 Sep 2021 14:47:46 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A00617.=E5=90=88=E5=B9=B6?=
 =?UTF-8?q?=E4=BA=8C=E5=8F=89=E6=A0=91.md=E9=98=9F=E5=88=97=E8=BF=AD?=
 =?UTF-8?q?=E4=BB=A3Java=E8=A7=A3=E6=B3=95?=
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---
 problems/0617.合并二叉树.md | 39 +++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/problems/0617.合并二叉树.md b/problems/0617.合并二叉树.md
index 22a527f9..e21efcb3 100644
--- a/problems/0617.合并二叉树.md
+++ b/problems/0617.合并二叉树.md
@@ -274,7 +274,7 @@ class Solution {
 
 ```Java
 class Solution {
-   // 迭代
+    // 使用栈迭代
     public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {
         if (root1 == null) {
             return root2;
@@ -310,6 +310,43 @@ class Solution {
     }
 }
 ```
+```java
+class Solution {
+    // 使用队列迭代
+    public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {
+        if (root1 == null) return root2;
+        if (root2 ==null) return root1;
+        Queue<TreeNode> queue = new LinkedList<>();
+        queue.offer(root1);
+        queue.offer(root2);
+        while (!queue.isEmpty()) {
+            TreeNode node1 = queue.poll();
+            TreeNode node2 = queue.poll();
+            // 此时两个节点一定不为空，val相加
+            node1.val = node1.val + node2.val;
+            // 如果两棵树左节点都不为空，加入队列
+            if (node1.left != null && node2.left != null) {
+                queue.offer(node1.left);
+                queue.offer(node2.left);
+            }
+            // 如果两棵树右节点都不为空，加入队列
+            if (node1.right != null && node2.right != null) {
+                queue.offer(node1.right);
+                queue.offer(node2.right);
+            }
+            // 若node1的左节点为空，直接赋值
+            if (node1.left == null && node2.left != null) {
+                node1.left = node2.left;
+            }
+            // 若node2的左节点为空，直接赋值
+            if (node1.right == null && node2.right != null) {
+                node1.right = node2.right;
+            }
+        }
+        return root1;
+    }
+}
+```
 
 ## Python