diff --git a/problems/0226.翻转二叉树.md b/problems/0226.翻转二叉树.md
index 11517783..8691953a 100644
--- a/problems/0226.翻转二叉树.md
+++ b/problems/0226.翻转二叉树.md
@@ -1018,25 +1018,13 @@ public class Solution {
 ```csharp
 //迭代
 public class Solution {
-    public TreeNode InvertTree(TreeNode root) {
-          if (root == null) return null;
-        Stack<TreeNode> stack=new Stack<TreeNode>();
-        stack.Push(root);
-        while(stack.Count>0)
-        {
-            TreeNode node = stack.Pop();   
-            swap(node);
-            if(node.right!=null) stack.Push(node.right);   
-            if(node.left!=null) stack.Push(node.left);     
-        }
-        return root;
-    }
-
-    public void swap(TreeNode node) {
-        TreeNode temp = node.left;
-        node.left = node.right;
-        node.right = temp;
-    }
+public TreeNode InvertTree(TreeNode root) {
+    if(root == null) return root;
+    (root.left,root.right) = (root.right, root.left);
+    InvertTree(root.left);
+    InvertTree(root.right);
+    return root;
+}
 }
 ```