diff --git a/problems/0112.路径总和.md b/problems/0112.路径总和.md
index 6709a2fb..e6ccc6ae 100644
--- a/problems/0112.路径总和.md
+++ b/problems/0112.路径总和.md
@@ -564,10 +564,10 @@ class Solution:
             
         return False
     
-    def hasPathSum(self, root: TreeNode, sum: int) -> bool:
+    def hasPathSum(self, root: Optional[TreeNode], targetSum: int) -> bool:
         if root is None:
             return False
-        return self.traversal(root, sum - root.val)      
+        return self.traversal(root, targetSum - root.val)      
 ```
 
 (版本二) 递归 + 精简
@@ -579,12 +579,12 @@ class Solution:
 #         self.left = left
 #         self.right = right
 class Solution:
-    def hasPathSum(self, root: TreeNode, sum: int) -> bool:
+    def hasPathSum(self, root: Optional[TreeNode], targetSum: int) -> bool:
         if not root:
             return False
-        if not root.left and not root.right and sum == root.val:
+        if not root.left and not root.right and targetSum == root.val:
             return True
-        return self.hasPathSum(root.left, sum - root.val) or self.hasPathSum(root.right, sum - root.val)
+        return self.hasPathSum(root.left, targetSum - root.val) or self.hasPathSum(root.right, targetSum - root.val)
   
 ```
 (版本三) 迭代
@@ -596,7 +596,7 @@ class Solution:
 #         self.left = left
 #         self.right = right
 class Solution:
-    def hasPathSum(self, root: TreeNode, sum: int) -> bool:
+    def hasPathSum(self, root: Optional[TreeNode], targetSum: int) -> bool:
         if not root:
             return False
         # 此时栈里要放的是pair<节点指针，路径数值>
@@ -659,13 +659,13 @@ class Solution:
 
         return
 
-    def pathSum(self, root: TreeNode, sum: int) -> List[List[int]]:
+    def pathSum(self, root: Optional[TreeNode], targetSum: int) -> List[List[int]]:
         self.result.clear()
         self.path.clear()
         if not root:
             return self.result
         self.path.append(root.val) # 把根节点放进路径
-        self.traversal(root, sum - root.val)
+        self.traversal(root, targetSum - root.val)
         return self.result 
 ```
 
@@ -678,7 +678,7 @@ class Solution:
 #         self.left = left
 #         self.right = right
 class Solution:
-    def pathSum(self, root: TreeNode, targetSum: int) -> List[List[int]]:
+    def pathSum(self, root: Optional[TreeNode], targetSum: int) -> List[List[int]]:
         
         result = []
         self.traversal(root, targetSum, [], result)
@@ -703,7 +703,7 @@ class Solution:
 #         self.left = left
 #         self.right = right
 class Solution:
-    def pathSum(self, root: TreeNode, targetSum: int) -> List[List[int]]:
+    def pathSum(self, root: Optional[TreeNode], targetSum: int) -> List[List[int]]:
         if not root:
             return []
         stack = [(root, [root.val])]
diff --git a/problems/0513.找树左下角的值.md b/problems/0513.找树左下角的值.md
index d69ceb6f..c7446726 100644
--- a/problems/0513.找树左下角的值.md
+++ b/problems/0513.找树左下角的值.md
@@ -55,7 +55,7 @@
 
 参数必须有要遍历的树的根节点，还有就是一个int型的变量用来记录最长深度。 这里就不需要返回值了，所以递归函数的返回类型为void。
 
-本题还需要类里的两个全局变量，maxLen用来记录最大深度，result记录最大深度最左节点的数值。
+本题还需要类里的两个全局变量，maxDepth用来记录最大深度，result记录最大深度最左节点的数值。
 
 代码如下：