diff --git a/problems/二叉树的递归遍历.md b/problems/二叉树的递归遍历.md
index bd3a9e1c..02d4b060 100644
--- a/problems/二叉树的递归遍历.md
+++ b/problems/二叉树的递归遍历.md
@@ -125,17 +125,17 @@ Go：
 前序遍历:
 ```
 func PreorderTraversal(root *TreeNode) (res []int) {
-	var traversal func(node *TreeNode)
-	traversal = func(node *TreeNode) {
-		if node == nil {
-			return
-		}
-		res = append(res,node.Val)
-		traversal(node.Left)
-		traversal(node.Right)
+    var traversal func(node *TreeNode)
+    traversal = func(node *TreeNode) {
+	if node == nil {
+            return
 	}
-	traversal(root)
-	return res
+	res = append(res,node.Val)
+	traversal(node.Left)
+	traversal(node.Right)
+    }
+    traversal(root)
+    return res
 }
 
 ```
@@ -143,34 +143,34 @@ func PreorderTraversal(root *TreeNode) (res []int) {
 
 ```
 func InorderTraversal(root *TreeNode) (res []int) {
-	var traversal func(node *TreeNode)
-	traversal = func(node *TreeNode) {
-		if node == nil {
-			return
-		}
-		traversal(node.Left)
-		res = append(res,node.Val)
-		traversal(node.Right)
+    var traversal func(node *TreeNode)
+    traversal = func(node *TreeNode) {
+	if node == nil {
+		return
 	}
-	traversal(root)
-	return res
+	traversal(node.Left)
+	res = append(res,node.Val)
+	traversal(node.Right)
+    }
+    traversal(root)
+    return res
 }
 ```
 后序遍历:
 
 ```
 func PostorderTraversal(root *TreeNode) (res []int) {
-	var traversal func(node *TreeNode)
-	traversal = func(node *TreeNode) {
-		if node == nil {
-			return
-		}
-		traversal(node.Left)
-		traversal(node.Right)
-    res = append(res,node.Val)
+    var traversal func(node *TreeNode)
+    traversal = func(node *TreeNode) {
+	if node == nil {
+		return
 	}
-	traversal(root)
-	return res
+	traversal(node.Left)
+	traversal(node.Right)
+        res = append(res,node.Val)
+    }
+    traversal(root)
+    return res
 }
 ```