Update 136._single_number.md

Author: 0xkookoo

docs/Leetcode_Solutions/Python/136._single_number.md

@@ -1,17 +1,36 @@
-### 136. Single Number
+# 136. Single Number
 
+**<font color=red>难度: Easy</font>**
 
+## 刷题内容
 
-题目:
-<https://leetcode.com/problems/single-number/>
+> 原题连接
 
+* https://leetcode.com/problems/single-number/description/
 
-难度:
+> 内容描述
 
-Easy
+```
+Given a non-empty array of integers, every element appears twice except for one. Find that single one.
+
+Note:
+
+Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?
+
+Example 1:
 
+Input: [2,2,1]
+Output: 1
+Example 2:
 
-思路：
+Input: [4,1,2,1,2]
+Output: 4
+```
+
+## 解题方案
+
+> 思路 1
+******- 时间复杂度: O(N)******- 空间复杂度: O(N)******
 
 位运算，终于要take it了
 
@@ -24,7 +43,7 @@ Easy
 Python的位操作：
 <https://wiki.python.org/moin/BitwiseOperators>
 
-神奇的解法：
+
 
 
 ```python