From 60799a2f446b0b54bb6dcf29ef302ecf9dfeb3e6 Mon Sep 17 00:00:00 2001
From: posper <xsduan1998@163.com>
Date: Tue, 3 Aug 2021 20:53:53 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BA=8C=E5=8F=89=E6=A0=91=E5=B1=82=E5=BA=8F?=
 =?UTF-8?q?=E9=81=8D=E5=8E=86=20116.=E5=A1=AB=E5=85=85=E6=AF=8F=E4=B8=AA?=
 =?UTF-8?q?=E8=8A=82=E7=82=B9=E7=9A=84=E4=B8=8B=E4=B8=80=E4=B8=AA=E5=8F=B3?=
 =?UTF-8?q?=E4=BE=A7=E8=8A=82=E7=82=B9=E6=8C=87=E9=92=88=20=E6=B7=BB?=
 =?UTF-8?q?=E5=8A=A0Java=E7=89=88=E6=9C=AC?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 problems/0102.二叉树的层序遍历.md | 38 +++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/problems/0102.二叉树的层序遍历.md b/problems/0102.二叉树的层序遍历.md
index 8be3ac47..7d459ad9 100644
--- a/problems/0102.二叉树的层序遍历.md
+++ b/problems/0102.二叉树的层序遍历.md
@@ -1254,6 +1254,44 @@ func connect(root *Node) *Node {
 }
 ```
 
+Java 代码：
+
+```java
+// 二叉树之层次遍历
+class Solution {
+    public Node connect(Node root) {
+        Queue<Node> queue = new LinkedList<>();
+        if (root != null) {
+            queue.add(root);
+        }
+        while (!queue.isEmpty()) {
+            int size = queue.size();
+            Node node = null;
+            Node nodePre = null;
+ 
+            for (int i = 0; i < size; i++) {
+                if (i == 0) {
+                    nodePre = queue.poll(); // 取出本层头一个节点
+                    node = nodePre;
+                } else {
+                    node = queue.poll();
+                    nodePre.next = node; // 本层前一个节点 next 指向当前节点
+                    nodePre = nodePre.next;
+                }
+                if (node.left != null) {
+                    queue.add(node.left);
+                }
+                if (node.right != null) {
+                    queue.add(node.right);
+                }
+            }
+            nodePre.next = null; // 本层最后一个节点 next 指向 null
+        }
+        return root;
+    }
+}
+```
+
 ## 117.填充每个节点的下一个右侧节点指针II
 
 题目地址：https://leetcode-cn.com/problems/populating-next-right-pointers-in-each-node-ii/