feat: add swift implementation to lcof2 problem: No.043 (#3053)

Author: klever34

lcof2/剑指 Offer II 043. 往完全二叉树添加节点/README.md

@@ -420,6 +420,68 @@ CBTInserter.prototype.get_root = function () {
  */
 ```
 
+#### Swift
+
+```swift
+/* public class TreeNode {
+*     public var val: Int
+*     public var left: TreeNode?
+*     public var right: TreeNode?
+*     public init() { self.val = 0; self.left = nil; self.right = nil; }
+*     public init(_ val: Int) { self.val = val; self.left = nil; self.right = nil; }
+*     public init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {
+*         self.val = val
+*         self.left = left
+*         self.right = right
+*     }
+* }
+*/
+
+class CBTInserter {
+    private var tree: [TreeNode] = []
+
+    init(_ root: TreeNode?) {
+        guard let root = root else { return }
+        var q: [TreeNode] = [root]
+        while !q.isEmpty {
+            for _ in 0..<q.count {
+                let node = q.removeFirst()
+                tree.append(node)
+                if let left = node.left {
+                    q.append(left)
+                }
+                if let right = node.right {
+                    q.append(right)
+                }
+            }
+        }
+    }
+
+    func insert(_ val: Int) -> Int {
+        let p = tree[(tree.count - 1) / 2]
+        let node = TreeNode(val)
+        tree.append(node)
+        if p.left == nil {
+            p.left = node
+        } else {
+            p.right = node
+        }
+        return p.val
+    }
+
+    func get_root() -> TreeNode? {
+        return tree.isEmpty ? nil : tree[0]
+    }
+}
+
+/**
+ * Your CBTInserter object will be instantiated and called as such:
+ * let obj = CBTInserter(root)
+ * let param_1 = obj.insert(val)
+ * let param_2 = obj.get_root()
+ */
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 043. 往完全二叉树添加节点/Solution.swift

@@ -0,0 +1,57 @@
+/* public class TreeNode {
+*     public var val: Int
+*     public var left: TreeNode?
+*     public var right: TreeNode?
+*     public init() { self.val = 0; self.left = nil; self.right = nil; }
+*     public init(_ val: Int) { self.val = val; self.left = nil; self.right = nil; }
+*     public init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {
+*         self.val = val
+*         self.left = left
+*         self.right = right
+*     }
+* }
+*/
+
+class CBTInserter {
+    private var tree: [TreeNode] = []
+
+    init(_ root: TreeNode?) {
+        guard let root = root else { return }
+        var q: [TreeNode] = [root]
+        while !q.isEmpty {
+            for _ in 0..<q.count {
+                let node = q.removeFirst()
+                tree.append(node)
+                if let left = node.left {
+                    q.append(left)
+                }
+                if let right = node.right {
+                    q.append(right)
+                }
+            }
+        }
+    }
+
+    func insert(_ val: Int) -> Int {
+        let p = tree[(tree.count - 1) / 2]
+        let node = TreeNode(val)
+        tree.append(node)
+        if p.left == nil {
+            p.left = node
+        } else {
+            p.right = node
+        }
+        return p.val
+    }
+
+    func get_root() -> TreeNode? {
+        return tree.isEmpty ? nil : tree[0]
+    }
+}
+
+/**
+ * Your CBTInserter object will be instantiated and called as such:
+ * let obj = CBTInserter(root)
+ * let param_1 = obj.insert(val)
+ * let param_2 = obj.get_root()
+ */