Merge pull request #324 from borninfreedom/master

add python codes of binary tree's level order

problems/0102.二叉树的层序遍历.md

@@ -80,6 +80,40 @@ public:
     }
 };
 ```
+python代码：
+
+```python
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class Solution:
+    def levelOrder(self, root: TreeNode) -> List[List[int]]:
+        if not root:
+            return []
+
+        quene = [root]
+        out_list = []
+
+        while quene:
+            in_list = []
+            for i in range(len(quene)):
+                node = quene.pop(0)
+                in_list.append(node.val)
+                if node.left:
+                    quene.append(node.left)
+                if node.right:
+                    quene.append(node.right)
+            
+            out_list.append(in_list)
+
+        return out_list
+```
+
+
+
 javascript代码：
 
 ```javascript