add python 114

python-leetcode/README.md

@@ -55,6 +55,7 @@
 41. [删除给定值的叶子节点](./solution/tree/leetcode_1325_.py)
 42. [找树左下角的值](./solution/tree/leetcode_513_.py)
 43. [完全二叉树的节点个数](./solution/tree/leetcode_222_.py)
+44. [二叉树展开为链表](./solution/tree/leetcode_114_.py)
 
 
 

python-leetcode/solution/tree/leetcode_114_.py

+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# coding=utf-8
+"""
+114. 二叉树展开为链表
+"""
+from solution import TreeNode
+
+
+class Solution:
+    pre = None
+
+    def flatten(self, root: TreeNode) -> None:
+        """
+        Do not return anything, modify root in-place instead.
+        """
+        if not root:
+            return None
+        self.flatten(root.right)
+        self.flatten(root.left)
+        root.right = self.pre
+        root.left = None
+        self.pre = root