feat: add swift implementation to lcci problem: No.04.08 (doocs#2659)

klever34 · web-flow · commit 1e45282d1dba · 2024-04-25T18:45:43.000+08:00
diff --git a/lcci/04.08.First Common Ancestor/README.md b/lcci/04.08.First Common Ancestor/README.md
@@ -55,6 +55,38 @@ class Solution {
 }
 ```
 
+```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 lowestCommonAncestor(_ root: TreeNode?, _ p: TreeNode?, _ q: TreeNode?) -> TreeNode? {
+        if root == nil || root === p || root === q {
+            return root
+        }
+        let left = lowestCommonAncestor(root?.left, p, q)
+        let right = lowestCommonAncestor(root?.right, p, q)
+        if left == nil {
+            return right
+        } else if right == nil {
+            return left
+        } else {
+            return root
+        }
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->
diff --git a/lcci/04.08.First Common Ancestor/README_EN.md b/lcci/04.08.First Common Ancestor/README_EN.md
@@ -101,6 +101,38 @@ class Solution {
 }
 ```
 
+```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 lowestCommonAncestor(_ root: TreeNode?, _ p: TreeNode?, _ q: TreeNode?) -> TreeNode? {
+        if root == nil || root === p || root === q {
+            return root
+        }
+        let left = lowestCommonAncestor(root?.left, p, q)
+        let right = lowestCommonAncestor(root?.right, p, q)
+        if left == nil {
+            return right
+        } else if right == nil {
+            return left
+        } else {
+            return root
+        }
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->
diff --git a/lcci/04.08.First Common Ancestor/Solution.swift b/lcci/04.08.First Common Ancestor/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 lowestCommonAncestor(_ root: TreeNode?, _ p: TreeNode?, _ q: TreeNode?) -> TreeNode? {
+        if root == nil || root === p || root === q {
+            return root
+        }
+        let left = lowestCommonAncestor(root?.left, p, q)
+        let right = lowestCommonAncestor(root?.right, p, q)
+        if left == nil {
+            return right
+        } else if right == nil {
+            return left
+        } else {
+            return root
+        }
+    }
+}
