From 541f384e7c8bda2d5d695429a6e4b7d118db1417 Mon Sep 17 00:00:00 2001
From: liuyuxin <gvenusleo@gmail.com>
Date: Sun, 14 May 2023 01:19:06 +0800
Subject: [PATCH] Fix function call error and null safety (#491)

---
 codes/dart/chapter_tree/avl_tree.dart           | 2 +-
 codes/dart/chapter_tree/binary_search_tree.dart | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/codes/dart/chapter_tree/avl_tree.dart b/codes/dart/chapter_tree/avl_tree.dart
index 379f68686..67fa1cd5a 100644
--- a/codes/dart/chapter_tree/avl_tree.dart
+++ b/codes/dart/chapter_tree/avl_tree.dart
@@ -143,7 +143,7 @@ class AVLTree {
         while (temp!.left != null) {
           temp = temp.left;
         }
-        node.right = removeHelper(node.right, temp!.val);
+        node.right = removeHelper(node.right, temp.val);
         node.val = temp.val;
       }
     }
diff --git a/codes/dart/chapter_tree/binary_search_tree.dart b/codes/dart/chapter_tree/binary_search_tree.dart
index 5c172e542..8ba6c2305 100644
--- a/codes/dart/chapter_tree/binary_search_tree.dart
+++ b/codes/dart/chapter_tree/binary_search_tree.dart
@@ -135,7 +135,7 @@ void main() {
   print("\n查找到的节点对象为 $node，节点值 = ${node?.val}");
 
   /* 插入节点 */
-  node = insert(16);
+  insert(16);
   print("\n插入节点 16 后，二叉树为\n");
   printTree(getRoot());