diff --git a/problems/二叉树中递归带着回溯.md b/problems/二叉树中递归带着回溯.md
index b21c7cfe..372a4660 100644
--- a/problems/二叉树中递归带着回溯.md
+++ b/problems/二叉树中递归带着回溯.md
@@ -90,6 +90,7 @@ public:
 
 
 如下为精简之后的递归代码：(257. 二叉树的所有路径)
+CPP
 ```
 class Solution {
 private: