feat: add swift implementation to lcci problem: No.04.06 (#2658)

Author: klever34

lcci/04.06.Successor/README.md

@@ -202,6 +202,38 @@ var inorderSuccessor = function (root, p) {
 };
 ```
 
+```swift
+/* class TreeNode {
+*    var val: Int
+*    var left: TreeNode?
+*    var right: TreeNode?
+*
+*    init(_ val: Int) {
+*        self.val = val
+*        self.left = nil
+*        self.right = nil
+*    }
+* }
+*/
+
+class Solution {
+    func inorderSuccessor(_ root: TreeNode?, _ p: TreeNode?) -> TreeNode? {
+        var current = root
+        var successor: TreeNode? = nil
+
+        while let node = current {
+            if node.val > p!.val {
+                successor = node
+                current = node.left
+            } else {
+                current = node.right
+            }
+        }
+        return successor
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/04.06.Successor/README_EN.md

@@ -221,6 +221,38 @@ var inorderSuccessor = function (root, p) {
 };
 ```
 
+```swift
+/* class TreeNode {
+*    var val: Int
+*    var left: TreeNode?
+*    var right: TreeNode?
+*
+*    init(_ val: Int) {
+*        self.val = val
+*        self.left = nil
+*        self.right = nil
+*    }
+* }
+*/
+
+class Solution {
+    func inorderSuccessor(_ root: TreeNode?, _ p: TreeNode?) -> TreeNode? {
+        var current = root
+        var successor: TreeNode? = nil
+
+        while let node = current {
+            if node.val > p!.val {
+                successor = node
+                current = node.left
+            } else {
+                current = node.right
+            }
+        }
+        return successor
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/04.06.Successor/Solution.swift

@@ -0,0 +1,29 @@
+/* class TreeNode {
+*    var val: Int
+*    var left: TreeNode?
+*    var right: TreeNode?
+*
+*    init(_ val: Int) {
+*        self.val = val
+*        self.left = nil
+*        self.right = nil
+*    }
+* } 
+*/
+
+class Solution {
+    func inorderSuccessor(_ root: TreeNode?, _ p: TreeNode?) -> TreeNode? {
+        var current = root
+        var successor: TreeNode? = nil
+        
+        while let node = current {
+            if node.val > p!.val {
+                successor = node
+                current = node.left
+            } else {
+                current = node.right
+            }
+        }
+        return successor
+    }
+}