Update 0102.二叉树的层序遍历.md

problems/0102.二叉树的层序遍历.md

@@ -2938,23 +2938,26 @@ Python 3：
 #         self.right = right
 class Solution:
     def minDepth(self, root: TreeNode) -> int:
-        if root == None:
+        if not root:
             return 0
+        depth = 0
+        queue = collections.deque([root])
+        
+        while queue:
+            depth += 1 
+            for _ in range(len(queue)):
+                node = queue.popleft()
+                
+                if not node.left and not node.right:
+                    return depth
+            
+                if node.left:
+                    queue.append(node.left)
+                    
+                if node.right:
+                    queue.append(node.right)
 
-        #根节点的深度为1
-        queue_ = [(root,1)]
-        while queue_:
-            cur, depth = queue_.pop(0)
-
-            if cur.left == None and cur.right == None:
-                return depth
-            #先左子节点，由于左子节点没有孩子，则就是这一层了
-            if cur.left:
-                queue_.append((cur.left,depth + 1))
-            if cur.right:
-                queue_.append((cur.right,depth + 1))
-
-        return 0
+        return depth
 ```
 
 Go：