diff --git a/problems/0236.二叉树的最近公共祖先.md b/problems/0236.二叉树的最近公共祖先.md
index 7b5deb56..41e12df4 100644
--- a/problems/0236.二叉树的最近公共祖先.md
+++ b/problems/0236.二叉树的最近公共祖先.md
@@ -249,7 +249,6 @@ class Solution {
 ```java
 // 代码精简版
 class Solution {
-    TreeNode pre;
     public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
         if (root == null || root.val == p.val ||root.val == q.val) return root;
         TreeNode left = lowestCommonAncestor(root.left,p,q);