Add solution 136

Author: yanglbme

README.md

@@ -24,6 +24,7 @@ Complete solutions to Leetcode problems, updated daily.
 | 053 | [Maximum Subarray](https://github.com/yanglbme/leetcode/tree/master/solution/053.Maximum%20Subarray) | `Array`, `Divide and Conquer`, `Dynamic Programming` |
 | 070 | [Climbing Stairs](https://github.com/yanglbme/leetcode/tree/master/solution/070.Climbing%20Stairs) | `Dynamic Programming` |
 | 083 | [Remove Duplicates from Sorted List](https://github.com/yanglbme/leetcode/tree/master/solution/083.Remove%20Duplicates%20from%20Sorted%20List) | `Linked List` |
+| 136 | [Single Number](https://github.com/yanglbme/leetcode/tree/master/solution/136.Single%20Number) | `Hash Table`, `Bit Manipulation` |
 | 189 | [Rotate Array](https://github.com/yanglbme/leetcode/tree/master/solution/189.Rotate%20Array) | `Array` |
 | 198 | [House Robber](https://github.com/yanglbme/leetcode/tree/master/solution/198.House%20Robber) | `Dynamic Programming` |
 | 203 | [Remove Linked List Elements](https://github.com/yanglbme/leetcode/tree/master/solution/203.Remove%20Linked%20List%20Elements) | `Linked List` |

solution/136.Single Number/README.md

@@ -0,0 +1,35 @@
+## 只出现一次的数字
+### 题目描述
+
+给定一个非空整数数组，除了某个元素只出现一次以外，其余每个元素均出现两次。找出那个只出现了一次的元素。
+
+说明：
+
+你的算法应该具有线性时间复杂度。 你可以不使用额外空间来实现吗？
+
+示例 1:
+```
+输入: [2,2,1]
+输出: 1
+```
+
+示例 2:
+```
+输入: [4,1,2,1,2]
+输出: 4
+```
+
+### 解法
+任意数与 0 异或，都等于它本身。而任意数与自身异或，都等于 0。
+
+```java
+class Solution {
+    public int singleNumber(int[] nums) {
+        int res = 0;
+        for (int num : nums) {
+            res ^= num;
+        }
+        return res;
+    }
+}
+```

solution/136.Single Number/Solution.java

@@ -0,0 +1,9 @@
+class Solution {
+    public int singleNumber(int[] nums) {
+        int res = 0;
+        for (int num : nums) {
+            res ^= num;
+        }
+        return res;
+    }
+}