feat: add swift implementation to lcp problem: No.39 (#3781)

Author: klever34

lcp/LCP 39. 无人机方阵/README.md

@@ -179,6 +179,35 @@ function minimumSwitchingTimes(source: number[][], target: number[][]): number {
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    func minimumSwitchingTimes(_ source: [[Int]], _ target: [[Int]]) -> Int {
+        var count = [Int: Int]()
+
+        for row in source {
+            for num in row {
+                count[num, default: 0] += 1
+            }
+        }
+
+        for row in target {
+            for num in row {
+                count[num, default: 0] -= 1
+            }
+        }
+
+        var result = 0
+        for value in count.values {
+            result += abs(value)
+        }
+
+        return result / 2
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcp/LCP 39. 无人机方阵/Solution.swift

@@ -0,0 +1,24 @@
+class Solution {
+    func minimumSwitchingTimes(_ source: [[Int]], _ target: [[Int]]) -> Int {
+        var count = [Int: Int]()
+        
+        for row in source {
+            for num in row {
+                count[num, default: 0] += 1
+            }
+        }
+        
+        for row in target {
+            for num in row {
+                count[num, default: 0] -= 1
+            }
+        }
+        
+        var result = 0
+        for value in count.values {
+            result += abs(value)
+        }
+        
+        return result / 2
+    }
+}