Update 0114._flatten_binary_tree_to_linked_list.md

docs/Leetcode_Solutions/Python/0114._flatten_binary_tree_to_linked_list.md

-### 114. Flatten Binary Tree to Linked List
+# 114. Flatten Binary Tree to Linked List
 
-题目:
-<https://leetcode.com/problems/flatten-binary-tree-to-linked-list/>
+**<font color=red>难度: Medium</font>**
 
+## 刷题内容
 
-难度:
+> 原题连接
 
-Medium
+* https://leetcode.com/problems/flatten-binary-tree-to-linked-list/
+
+> 内容描述
+
+```
+Given a binary tree, flatten it to a linked list in-place.
+
+For example, given the following tree:
+
+    1
+   / \
+  2   5
+ / \   \
+3   4   6
+The flattened tree should look like:
+
+1
+ \
+  2
+   \
+    3
+     \
+      4
+       \
+        5
+         \
+          6
+```
+
+## 解题方案
+
+> 思路 1
+******- 时间复杂度: O(N)******- 空间复杂度: O(N)******
 
 这道题看了hint，说每个node的右节点都是相应先序遍历中它的下一个节点。
 所以我的思路是先把先序遍历的node顺序搞出来，然后对于这里面的每一个节点，只需要做两个操作：
@@ -41,6 +73,9 @@ class Solution(object):
 ```
 beat 40.67%
 
+> 思路 2
+******- 时间复杂度: O(N)******- 空间复杂度: O(N)******
+
 另外一种解法：
 1. copy the left and right subtree
 2. then cut root’s left subtree