diff --git a/problems/0112.路径总和.md b/problems/0112.路径总和.md
index 41463ec1..2fdd7741 100644
--- a/problems/0112.路径总和.md
+++ b/problems/0112.路径总和.md
@@ -377,22 +377,22 @@ class solution {
 
 ```java
 class solution {
-    public list<list<integer>> pathsum(treenode root, int targetsum) {
-        list<list<integer>> res = new arraylist<>();
+    public List<List<Integer>> pathsum(TreeNode root, int targetsum) {
+        List<List<Integer>> res = new ArrayList<>();
         if (root == null) return res; // 非空判断
-        
-        list<integer> path = new linkedlist<>();
+
+        List<Integer> path = new LinkedList<>();
         preorderdfs(root, targetsum, res, path);
         return res;
     }
 
-    public void preorderdfs(treenode root, int targetsum, list<list<integer>> res, list<integer> path) {
+    public void preorderdfs(TreeNode root, int targetsum, List<List<Integer>> res, List<Integer> path) {
         path.add(root.val);
         // 遇到了叶子节点
         if (root.left == null && root.right == null) {
             // 找到了和为 targetsum 的路径
             if (targetsum - root.val == 0) {
-                res.add(new arraylist<>(path));
+                res.add(new ArrayList<>(path));
             }
             return; // 如果和不为 targetsum，返回
         }