feat: add swift implementation to lcof2 problem: No.053 (doocs#3068)

Author: klever34

lcof2/剑指 Offer II 053. 二叉搜索树中的中序后继/README.md

@@ -207,6 +207,49 @@ function inorderSuccessor(root: TreeNode | null, p: TreeNode | null): TreeNode |
 }
 ```
 
+#### 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 inorderSuccessor(_ root: TreeNode?, _ p: TreeNode?) -> TreeNode? {
+        var root = root
+        var ans: TreeNode? = nil
+        while root != nil {
+            if root!.val > p!.val {
+                ans = root
+                root = root!.left
+            } else {
+                root = root!.right
+            }
+        }
+        return ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof2/剑指 Offer II 053. 二叉搜索树中的中序后继/Solution.swift

@@ -0,0 +1,38 @@
+/* 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 inorderSuccessor(_ root: TreeNode?, _ p: TreeNode?) -> TreeNode? {
+        var root = root
+        var ans: TreeNode? = nil
+        while root != nil {
+            if root!.val > p!.val {
+                ans = root
+                root = root!.left
+            } else {
+                root = root!.right
+            }
+        }
+        return ans
+    }
+}