feat: add swift implementation to lcof problem: No.37 (#2907)

Author: klever34

lcof/面试题37. 序列化二叉树/README.md

@@ -462,6 +462,75 @@ public class Codec {
 // codec.deserialize(codec.serialize(root));
 ```
 
+#### Swift
+
+```swift
+
+/* public class TreeNode {
+*     var val: Int
+*     var left: TreeNode?
+*     var right: TreeNode?
+*     init(_ val: Int) {
+*         self.val = val
+*         self.left = nil
+*         self.right = nil
+*     }
+* }
+*/
+
+public class Codec {
+    func serialize(_ root: TreeNode?) -> String {
+        guard let root = root else {
+            return "null"
+        }
+        var result = [String]()
+        var queue = [TreeNode?]()
+        queue.append(root)
+        while !queue.isEmpty {
+            let node = queue.removeFirst()
+            if let node = node {
+                result.append("\(node.val)")
+                queue.append(node.left)
+                queue.append(node.right)
+            } else {
+                result.append("#")
+            }
+        }
+        return result.joined(separator: ",")
+    }
+
+    func deserialize(_ data: String) -> TreeNode? {
+        if data == "null" {
+            return nil
+        }
+        let vals = data.split(separator: ",").map { String($0) }
+        var i = 0
+        let root = TreeNode(Int(vals[i])!)
+        var queue = [TreeNode]()
+        queue.append(root)
+        i += 1
+        while !queue.isEmpty {
+            let node = queue.removeFirst()
+            if vals[i] != "#" {
+                node.left = TreeNode(Int(vals[i])!)
+                queue.append(node.left!)
+            }
+            i += 1
+            if vals[i] != "#" {
+                node.right = TreeNode(Int(vals[i])!)
+                queue.append(node.right!)
+            }
+            i += 1
+        }
+        return root
+    }
+}
+// Your Codec object will be instantiated and called as such:
+// let codec = Codec()
+// let serializedData = codec.serialize(root)
+// let deserializedTree = codec.deserialize(serializedData)
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof/面试题37. 序列化二叉树/Solution.swift

@@ -0,0 +1,60 @@
+
+/* public class TreeNode {
+*     var val: Int
+*     var left: TreeNode?
+*     var right: TreeNode?
+*     init(_ val: Int) {
+*         self.val = val
+*         self.left = nil
+*         self.right = nil
+*     }
+* }
+*/
+
+public class Codec {
+    func serialize(_ root: TreeNode?) -> String {
+        guard let root = root else {
+            return "null"
+        }
+        var result = [String]()
+        var queue = [TreeNode?]()
+        queue.append(root)
+        while !queue.isEmpty {
+            let node = queue.removeFirst()
+            if let node = node {
+                result.append("\(node.val)")
+                queue.append(node.left)
+                queue.append(node.right)
+            } else {
+                result.append("#")
+            }
+        }
+        return result.joined(separator: ",")
+    }
+
+    func deserialize(_ data: String) -> TreeNode? {
+        if data == "null" {
+            return nil
+        }
+        let vals = data.split(separator: ",").map { String($0) }
+        var i = 0
+        let root = TreeNode(Int(vals[i])!)
+        var queue = [TreeNode]()
+        queue.append(root)
+        i += 1
+        while !queue.isEmpty {
+            let node = queue.removeFirst()
+            if vals[i] != "#" {
+                node.left = TreeNode(Int(vals[i])!)
+                queue.append(node.left!)
+            }
+            i += 1
+            if vals[i] != "#" {
+                node.right = TreeNode(Int(vals[i])!)
+                queue.append(node.right!)
+            }
+            i += 1
+        }
+        return root
+    }
+}