From a11c78a19d95f7091681651e071f87fb169009e3 Mon Sep 17 00:00:00 2001
From: SUNLIFAN <lifansun1412@gmail.com>
Date: Thu, 19 Jan 2023 09:58:56 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A00107=E4=BA=8C=E5=8F=89?=
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---
 ...02\345\272\217\351\201\215\345\216\206.md" | 40 ++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git "a/problems/0102.\344\272\214\345\217\211\346\240\221\347\232\204\345\261\202\345\272\217\351\201\215\345\216\206.md" "b/problems/0102.\344\272\214\345\217\211\346\240\221\347\232\204\345\261\202\345\272\217\351\201\215\345\216\206.md"
index 220232a2b1..21f5147dd3 100644
--- "a/problems/0102.\344\272\214\345\217\211\346\240\221\347\232\204\345\261\202\345\272\217\351\201\215\345\216\206.md"
+++ "b/problems/0102.\344\272\214\345\217\211\346\240\221\347\232\204\345\261\202\345\272\217\351\201\215\345\216\206.md"
@@ -562,6 +562,45 @@ public class N0107 {
 }
 ```
 
+```java
+/**
+ * 思路和模板相同, 对收集答案的方式做了优化, 最后不需要反转
+ */
+class Solution {
+    public List<List<Integer>> levelOrderBottom(TreeNode root) {
+        // 利用链表可以进行 O(1) 头部插入, 这样最后答案不需要再反转
+        LinkedList<List<Integer>> ans = new LinkedList<>();
+        
+        Queue<TreeNode> q = new LinkedList<>();
+
+        if (root != null) q.offer(root);
+
+        while (!q.isEmpty()) {
+            int size = q.size();
+
+            List<Integer> temp = new ArrayList<>();
+
+            for (int i = 0; i < size; i ++) {
+                TreeNode node = q.poll();
+                
+                temp.add(node.val);
+                
+                if (node.left != null) q.offer(node.left);
+
+                if (node.right != null) q.offer(node.right);
+            }
+
+            // 新遍历到的层插到头部, 这样就满足按照层次反序的要求
+            ans.addFirst(temp);
+        }
+
+        return ans;
+    }
+}
+```
+
+
+
 go:
 
 ```GO
@@ -3013,4 +3052,3 @@ impl Solution {
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>
 </a>
-