diff --git a/problems/0112.路径总和.md b/problems/0112.路径总和.md
index 9b6027d1..5958de93 100644
--- a/problems/0112.路径总和.md
+++ b/problems/0112.路径总和.md
@@ -250,7 +250,7 @@ private:
     vector<vector<int>> result;
     vector<int> path;
     // 递归函数不需要返回值，因为我们要遍历整个树
-    void traversal(treenode* cur, int count) {
+    void traversal(TreeNode* cur, int count) {
         if (!cur->left && !cur->right && count == 0) { // 遇到了叶子节点且找到了和为sum的路径
             result.push_back(path);
             return;
@@ -276,10 +276,10 @@ private:
     }
 
 public:
-    vector<vector<int>> pathsum(treenode* root, int sum) {
+    vector<vector<int>> pathSum(TreeNode* root, int sum) {
         result.clear();
         path.clear();
-        if (root == null) return result;
+        if (root == NULL) return result;
         path.push_back(root->val); // 把根节点放进路径
         traversal(root, sum - root->val);
         return result;