Merge pull request soapyigu#203 from soapyigu/Math

[Math] Add a solution to Hamming Distance

Math/HammingDistance.swift

@@ -0,0 +1,19 @@
+/**
+ * Question Link: https://leetcode.com/problems/hamming-distance/
+ * Primary idea: Bit manipulation, use xor and right shift
+ *
+ * Time Complexity: O(n), Space Complexity: O(1)
+ */
+
+class HammingDistance {
+    func hammingDistance(_ x: Int, _ y: Int) -> Int {
+        var z = x ^ y, count = 0
+
+        while z > 0 {
+            count = z & 1 == 1 ? count + 1 : count
+            z = z >> 1
+        }
+
+        return count
+    }
+}

README.md

@@ -27,7 +27,7 @@
 * [Microsoft](#microsoft)
 
 ## Progress
-[Problem Status](#problem-status) shows the latest progress to all 400+ questions. Currently we have 211 completed solutions. Note: questions with ♥ mark means that you have to **Subscript to premium membership** of LeetCode to unlock them. Thank you for great contributions from [CharleneJiang](https://github.com/CharleneJiang), [ReadmeCritic](https://github.com/ReadmeCritic), [demonkoo](https://github.com/demonkoo), [DaiYue](https://github.com/DaiYue), [Quaggie](https://github.com/Quaggie) and [jindulys](https://github.com/jindulys).
+[Problem Status](#problem-status) shows the latest progress to all 400+ questions. Currently we have 212 completed solutions. Note: questions with ♥ mark means that you have to **Subscript to premium membership** of LeetCode to unlock them. Thank you for great contributions from [CharleneJiang](https://github.com/CharleneJiang), [ReadmeCritic](https://github.com/ReadmeCritic), [demonkoo](https://github.com/demonkoo), [DaiYue](https://github.com/DaiYue), [Quaggie](https://github.com/Quaggie) and [jindulys](https://github.com/jindulys).
 
 
 ## Array
@@ -212,6 +212,7 @@
 [Add Two Numbers](https://leetcode.com/problems/add-two-numbers/)| [Swift](./Math/AddTwoNumbers.swift)| Medium| O(n)| O(1)|
 [Add Digits](https://leetcode.com/problems/add-digits/)| [Swift](./Math/AddDigits.swift)| Easy| O(1)| O(1)|
 [Plus One](https://leetcode.com/problems/plus-one/)| [Swift](./Math/PlusOne.swift)| Easy| O(n)| O(1)|
+[Hamming Distance](https://leetcode.com/problems/hamming-distance/)| [Swift](./Math/HammingDistance.swift)| Easy| O(n)| O(1)|
 [Integer Break](https://leetcode.com/problems/integer-break/)| [Swift](./Math/IntegerBreak.swift)| Medium| O(logn)| O(1)|
 [Happy Number](https://leetcode.com/problems/happy-number/)| [Swift](./Math/HappyNumber.swift)| Easy| O(n)| O(n)|
 [Single Number](https://leetcode.com/problems/single-number/)| [Swift](./Math/SingleNumber.swift)| Medium| O(n)| O(1)|