feat: add swift implementation to lcof2 problem: No.116 (#3694)

Author: klever34

lcof2/剑指 Offer II 116. 朋友圈/README.md

@@ -178,6 +178,40 @@ func findCircleNum(isConnected [][]int) int {
 }
 ```
 
+#### Swift
+
+```swift
+class Solution {
+    private var isConnected: [[Int]] = []
+    private var visited: [Bool] = []
+    private var n: Int = 0
+
+    func findCircleNum(_ isConnected: [[Int]]) -> Int {
+        self.isConnected = isConnected
+        self.n = isConnected.count
+        self.visited = [Bool](repeating: false, count: n)
+        var numberOfCircles = 0
+
+        for i in 0..<n {
+            if !visited[i] {
+                dfs(i)
+                numberOfCircles += 1
+            }
+        }
+        return numberOfCircles
+    }
+
+    private func dfs(_ i: Int) {
+        visited[i] = true
+        for j in 0..<n {
+            if !visited[j] && isConnected[i][j] == 1 {
+                dfs(j)
+            }
+        }
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 116. 朋友圈/Solution.swift

@@ -0,0 +1,29 @@
+class Solution {
+    private var isConnected: [[Int]] = []
+    private var visited: [Bool] = []
+    private var n: Int = 0
+
+    func findCircleNum(_ isConnected: [[Int]]) -> Int {
+        self.isConnected = isConnected
+        self.n = isConnected.count
+        self.visited = [Bool](repeating: false, count: n)
+        var numberOfCircles = 0
+
+        for i in 0..<n {
+            if !visited[i] {
+                dfs(i)
+                numberOfCircles += 1
+            }
+        }
+        return numberOfCircles
+    }
+
+    private func dfs(_ i: Int) {
+        visited[i] = true
+        for j in 0..<n {
+            if !visited[j] && isConnected[i][j] == 1 {
+                dfs(j)
+            }
+        }
+    }
+}