feat: add swift implementation to lcof2 problem: No.046 (#3061)

Author: klever34

lcof2/剑指 Offer II 046. 二叉树的右侧视图/README.md

@@ -200,6 +200,56 @@ func rightSideView(root *TreeNode) []int {
 }
 ```
 
+#### Swift
+
+```swift
+/* class TreeNode {
+*     var val: Int
+*     var left: TreeNode?
+*     var right: TreeNode?
+*     init() {
+*         self.val = 0
+*         self.left = nil
+*         self.right = nil
+*     }
+*     init(_ val: Int) {
+*         self.val = val
+*         self.left = nil
+*         self.right = nil
+*     }
+*     init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {
+*         self.val = val
+*         self.left = left
+*         self.right = right
+*     }
+* }
+*/
+
+class Solution {
+    func rightSideView(_ root: TreeNode?) -> [Int] {
+        var ans = [Int]()
+        guard let root = root else {
+            return ans
+        }
+        var q = [TreeNode]()
+        q.append(root)
+        while !q.isEmpty {
+            ans.append(q[0].val)
+            for _ in 0..<q.count {
+                let node = q.removeFirst()
+                if let right = node.right {
+                    q.append(right)
+                }
+                if let left = node.left {
+                    q.append(left)
+                }
+            }
+        }
+        return ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 046. 二叉树的右侧视图/Solution.swift

@@ -0,0 +1,45 @@
+/* class TreeNode {
+*     var val: Int
+*     var left: TreeNode?
+*     var right: TreeNode?
+*     init() {
+*         self.val = 0
+*         self.left = nil
+*         self.right = nil
+*     }
+*     init(_ val: Int) {
+*         self.val = val
+*         self.left = nil
+*         self.right = nil
+*     }
+*     init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {
+*         self.val = val
+*         self.left = left
+*         self.right = right
+*     }
+* }
+*/
+
+class Solution {
+    func rightSideView(_ root: TreeNode?) -> [Int] {
+        var ans = [Int]()
+        guard let root = root else {
+            return ans
+        }
+        var q = [TreeNode]()
+        q.append(root)
+        while !q.isEmpty {
+            ans.append(q[0].val)
+            for _ in 0..<q.count {
+                let node = q.removeFirst()
+                if let right = node.right {
+                    q.append(right)
+                }
+                if let left = node.left {
+                    q.append(left)
+                }
+            }
+        }
+        return ans
+    }
+}