Swift implementation for LCOF 68-I

Author: klever34

lcof/面试题68 - I. 二叉搜索树的最近公共祖先/README.md

@@ -270,6 +270,40 @@ var lowestCommonAncestor = function (root, p, q) {
 };
 ```
 
+#### 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 Solution {
+    func lowestCommonAncestor(_ root: TreeNode?, _ p: TreeNode, _ q: TreeNode) -> TreeNode? {
+        var node = root
+        while let current = node {
+            if current.val < p.val && current.val < q.val {
+                node = current.right
+            } else if current.val > p.val && current.val > q.val {
+                node = current.left
+            } else {
+                return current
+            }
+        }
+        return nil
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcof/面试题68 - I. 二叉搜索树的最近公共祖先/Solution.swift

@@ -0,0 +1,29 @@
+/* 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 Solution {
+    func lowestCommonAncestor(_ root: TreeNode?, _ p: TreeNode, _ q: TreeNode) -> TreeNode? {
+        var node = root
+        while let current = node {
+            if current.val < p.val && current.val < q.val {
+                node = current.right
+            } else if current.val > p.val && current.val > q.val {
+                node = current.left
+            } else {
+                return current
+            }
+        }
+        return nil
+    }
+}