solve problem Single Number II

Author: P-ppc

README.md

@@ -39,6 +39,7 @@ All solutions will be accepted!
 |404|[Sum Of Left Leaves](https://leetcode-cn.com/problems/sum-of-left-leaves/description/)|[java/py/js](./algorithms/SumOfLeftLeaves)|Easy|
 |283|[Move Zeroes](https://leetcode-cn.com/problems/move-zeroes/description/)|[java/py/js](./algorithms/MoveZeroes)|Easy|
 |136|[Single Number](https://leetcode-cn.com/problems/single-number/description/)|[java/py/js](./algorithms/SingleNumber)|Easy|
+|137|[Single Number II](https://leetcode-cn.com/problems/single-number-ii/description/)|[java/py/js](./algorithms/SingleNumberII)|Medium|
 |1|[Two Sum](https://leetcode-cn.com/problems/two-sum/description/)|[java/py/js](./algorithms/TwoSum)|Easy|
 |167|[Two Sum II Input Array Is Sorted](https://leetcode-cn.com/problems/two-sum-ii-input-array-is-sorted/description/)|[java/py/js](./algorithms/TwoSumIIInputArrayIsSorted)|Easy|
 |653|[Two Sum IV Input Is A Bst](https://leetcode-cn.com/problems/two-sum-iv-input-is-a-bst/description/)|[java/py/js](./algorithms/TwoSumIVInputIsABst)|Easy|

algorithms/SingleNumberII/README.md

@@ -0,0 +1,2 @@
+# Single Number II
+We can solve this problem by bitwise

algorithms/SingleNumberII/Solution.java

@@ -0,0 +1,16 @@
+class Solution {
+    public int singleNumber(int[] nums) {
+        int[] bitMap = new int[32];
+        int res = 0;
+        
+        for (int i = 0; i < 32; i++) {
+            for (int num : nums) {
+                bitMap[i] += num >> i & 1;
+            }
+            
+            res |= bitMap[i] % 3 << i;
+        }
+        
+        return res;
+    }
+}

algorithms/SingleNumberII/solution.js

@@ -0,0 +1,20 @@
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var singleNumber = function(nums) {
+    let bitMap = new Array(32),
+        res = 0
+    
+    bitMap.fill(0)
+    
+    for (let i = 0; i < 32; i++) {
+        nums.forEach(num => {
+            bitMap[i] += num >> i & 1
+        })
+        
+        res |= bitMap[i] % 3 << i
+    }
+    
+    return res
+};

algorithms/SingleNumberII/solution.py

@@ -0,0 +1,17 @@
+class Solution(object):
+    def singleNumber(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        bit_map = [0] * 32
+        res = 0
+
+        for i in range(32):
+            for num in nums:
+                bit_map[i] += num >> i & 1
+            res |= bit_map[i] % 3 << i
+            # handle the negative in python
+            if i == 31 and bit_map[i] % 3 == 1:
+                res -= 0xFFFFFFFF + 1
+        return res