add: Single Number II

Author: hijiangtao

README.md

@@ -43,6 +43,7 @@ This is the solutions collection of my LeetCode submissions, most of them are pr
 |130|[Surrounded Regions](https://leetcode.com/problems/surrounded-regions/) | [JavaScript](./src/surrounded-regions/res.js)|Medium|
 |133|[Clone Graph](https://leetcode.com/problems/clone-graph/) | [JavaScript](./src/clone-graph/res.js)|Medium|
 |136|[Single Number](https://leetcode.com/problems/single-number/) | [JavaScript](./src/single-number/res.js)|Easy|
+|137|[Single Number II](https://leetcode.com/problems/single-number-ii/) | [JavaScript](./src/single-number-ii/res.js)|Medium|
 |151|[Reverse Words in a String](https://leetcode.com/problems/reverse-words-in-a-string/) | [JavaScript](./src/reverse-words-in-a-string/res.js)|Medium|
 |152|[Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/) | [JavaScript](./src/maximum-product-subarray/res.js)|Medium|
 |165|[Compare Version Numbers](https://leetcode.com/problems/compare-version-numbers/) | [JavaScript](./src/compare-version-numbers/res.js)|Medium|

src/single-number-ii/res.js

@@ -0,0 +1,44 @@
+/**
+ * res.js
+ * @authors Joe Jiang (hijiangtao@gmail.com)
+ * @date    2017-05-22 22:23:17
+ * @version $Id$
+ */
+
+/**
+ * Solution 1: https://discuss.leetcode.com/topic/43166/java-o-n-easy-to-understand-solution-easily-extended-to-any-times-of-occurance
+ * Solution 2: https://discuss.leetcode.com/topic/2031/challenge-me-thx/5
+ * Solution 3: https://discuss.leetcode.com/topic/2926/accepted-code-with-proper-explaination-does-anyone-have-a-better-idea/4
+ * @param {number[]} nums
+ * @return {number}
+ */
+let singleNumber = function(nums) {
+    let len = nums.length,
+        ans = 0;
+
+    for (let i = 0; i < 32; i++) {
+        let tmp = 0;
+
+        for (let j = 0; j < len; j++) {
+            if ((nums[j] >> i) & 1 === 1) {
+                tmp++;
+            }
+        }
+
+        tmp %= 3;
+        if (tmp) {
+            ans |= tmp << i;
+        }
+    }
+
+    return ans;
+};
+
+// let singleNumber = function(nums) {
+//     let ones = 0, twos = 0;
+//     for(let i = 0; i < nums.length; i++){
+//         ones = (ones ^ nums[i]) & ~twos;
+//         twos = (twos ^ nums[i]) & ~ones;
+//     }
+//     return ones;
+// };