feat: add swift implementation to lcci problem: No.16.17 (doocs#2748)

Author: klever34

lcci/16.17.Contiguous Sequence/README.md

@@ -112,6 +112,22 @@ var maxSubArray = function (nums) {
 };
 ```
 
+```swift
+class Solution {
+    func maxSubArray(_ nums: [Int]) -> Int {
+        var ans = Int.min
+        var f = Int.min
+
+        for x in nums {
+            f = max(f, 0) + x
+            ans = max(ans, f)
+        }
+
+        return ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/16.17.Contiguous Sequence/README_EN.md

@@ -124,6 +124,22 @@ var maxSubArray = function (nums) {
 };
 ```
 
+```swift
+class Solution {
+    func maxSubArray(_ nums: [Int]) -> Int {
+        var ans = Int.min
+        var f = Int.min
+
+        for x in nums {
+            f = max(f, 0) + x
+            ans = max(ans, f)
+        }
+
+        return ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/16.17.Contiguous Sequence/Solution.swift

@@ -0,0 +1,13 @@
+class Solution {
+    func maxSubArray(_ nums: [Int]) -> Int {
+        var ans = Int.min
+        var f = Int.min
+
+        for x in nums {
+            f = max(f, 0) + x
+            ans = max(ans, f)
+        }
+
+        return ans
+    }
+}