Add a solution to Two Sum Less Than K

Array/TwoSumLessThanK.swift

@@ -0,0 +1,28 @@
+/**
+ * Question Link: https://leetcode.com/problems/two-sum-less-than-k/
+ * Primary idea: Sort the arry and use two pointers to get the closest maximum value.
+ *
+ * Note: Directly using two points and update values correspondly to try to solve the 
+ *       problem with O(n) time complexity does not work -- it has too many edge cases.
+ *
+ * Time Complexity: O(n), Space Complexity: O(n)
+ */
+
+class TwoSumLessThanK {
+    func twoSumLessThanK(_ A: [Int], _ K: Int) -> Int {
+        let sortedA = A.sorted()
+        var left = 0, right = sortedA.count - 1
+        var closest = -1
+
+        while left < right {
+            if sortedA[left] + sortedA[right] < K {
+                closest = max(sortedA[left] + sortedA[right], closest)
+                left += 1
+            } else {
+                right -= 1
+            }
+        }
+
+        return closest
+    }
+}

README.md

@@ -4,7 +4,7 @@
 ![Leetcode](./logo.png?style=centerme)
 
 ## Progress
-[Problem Status](#problem-status) shows the latest progress to all 800+ questions. Currently we have 275 completed solutions. Note: questions with ♥ mark means that you have to **Subscript to premium membership** of LeetCode to unlock them.
+[Problem Status](#problem-status) shows the latest progress to all 800+ questions. Currently we have 276 completed solutions. Note: questions with ♥ mark means that you have to **Subscript to premium membership** of LeetCode to unlock them.
 
 ## Contributors
 
@@ -58,6 +58,7 @@
 [Remove Element](https://leetcode.com/problems/remove-element/)| [Swift](./Array/RemoveElement.swift)| Easy| O(n)| O(1)|
 [Strobogrammatic Number](https://leetcode.com/problems/strobogrammatic-number/)| [Swift](./Array/StrobogrammaticNumber.swift)| Easy| O(n)| O(1)|
 [Two Sum](https://leetcode.com/problems/two-sum/)| [Swift](./Array/TwoSum.swift)| Easy| O(n)| O(n)|
+[Two Sum Less Than K](https://leetcode.com/problems/two-sum-less-than-k/)| [Swift](./Array/TwoSumLessThanK.swift)| Easy| O(nlogn)| O(n)|
 [3Sum](https://leetcode.com/problems/3sum/)| [Swift](./Array/ThreeSum.swift)| Medium| O(n^2)| O(nC3)|
 [3Sum Closest](https://leetcode.com/problems/3sum-closest/)| [Swift](./Array/ThreeSumClosest.swift)| Medium| O(n^2)| O(nC3)|
 [4Sum](https://leetcode.com/problems/4sum/)| [Swift](./Array/FourSum.swift)| Medium| O(n^3)| O(nC4)|