feat: add swift implementation to lcci problem: No.16.06 (#2729)

Author: klever34

Diff for: lcci/16.06.Smallest Difference/README.md

@@ -141,6 +141,41 @@ function smallestDifference(a: number[], b: number[]): number {
 }
 ```
 
+```swift
+class Solution {
+    func smallestDifference(_ a: [Int], _ b: [Int]) -> Int {
+        let sortedB = b.sorted()
+        var ans = Int.max
+        
+        for x in a {
+            let j = search(sortedB, x)
+            if j < sortedB.count {
+                ans = min(ans, abs(sortedB[j] - x))
+            }
+            if j > 0 {
+                ans = min(ans, abs(x - sortedB[j - 1]))
+            }
+        }
+        
+        return ans
+    }
+    
+    private func search(_ nums: [Int], _ x: Int) -> Int {
+        var l = 0
+        var r = nums.count
+        while l < r {
+            let mid = (l + r) / 2
+            if nums[mid] >= x {
+                r = mid
+            } else {
+                l = mid + 1
+            }
+        }
+        return l
+    }
+}
+```
+
 <!-- tabs:end -->
 
 ### 方法二：排序 + 双指针

Diff for: lcci/16.06.Smallest Difference/README_EN.md

@@ -147,6 +147,41 @@ function smallestDifference(a: number[], b: number[]): number {
 }
 ```
 
+```swift
+class Solution {
+    func smallestDifference(_ a: [Int], _ b: [Int]) -> Int {
+        let sortedB = b.sorted()
+        var ans = Int.max
+        
+        for x in a {
+            let j = search(sortedB, x)
+            if j < sortedB.count {
+                ans = min(ans, abs(sortedB[j] - x))
+            }
+            if j > 0 {
+                ans = min(ans, abs(x - sortedB[j - 1]))
+            }
+        }
+        
+        return ans
+    }
+    
+    private func search(_ nums: [Int], _ x: Int) -> Int {
+        var l = 0
+        var r = nums.count
+        while l < r {
+            let mid = (l + r) / 2
+            if nums[mid] >= x {
+                r = mid
+            } else {
+                l = mid + 1
+            }
+        }
+        return l
+    }
+}
+```
+
 <!-- tabs:end -->
 
 ### Solution 2: Sorting + Two Pointers

Diff for: lcci/16.06.Smallest Difference/Solution.swift

@@ -0,0 +1,32 @@
+class Solution {
+    func smallestDifference(_ a: [Int], _ b: [Int]) -> Int {
+        let sortedB = b.sorted()
+        var ans = Int.max
+        
+        for x in a {
+            let j = search(sortedB, x)
+            if j < sortedB.count {
+                ans = min(ans, abs(sortedB[j] - x))
+            }
+            if j > 0 {
+                ans = min(ans, abs(x - sortedB[j - 1]))
+            }
+        }
+        
+        return ans
+    }
+    
+    private func search(_ nums: [Int], _ x: Int) -> Int {
+        var l = 0
+        var r = nums.count
+        while l < r {
+            let mid = (l + r) / 2
+            if nums[mid] >= x {
+                r = mid
+            } else {
+                l = mid + 1
+            }
+        }
+        return l
+    }
+}