feat: add swift implementation to lcof2 problem: No.051 (doocs#3066)

klever34 · web-flow · commit 17b237075b16 · 2024-06-07T17:43:58.000+08:00
diff --git a/lcof2/剑指 Offer II 051. 节点之和最大的路径/README.md b/lcof2/剑指 Offer II 051. 节点之和最大的路径/README.md
@@ -348,6 +348,51 @@ public class Solution {
 }
 ```
 
+#### 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 {
+    private var ans = Int.min
+
+    func maxPathSum(_ root: TreeNode?) -> Int {
+        _ = dfs(root)
+        return ans
+    }
+
+    private func dfs(_ root: TreeNode?) -> Int {
+        guard let root = root else {
+            return 0
+        }
+        let left = max(0, dfs(root.left))
+        let right = max(0, dfs(root.right))
+        ans = max(ans, root.val + left + right)
+        return root.val + max(left, right)
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/lcof2/剑指 Offer II 051. 节点之和最大的路径/Solution.swift b/lcof2/剑指 Offer II 051. 节点之和最大的路径/Solution.swift
@@ -0,0 +1,40 @@
+/* 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 {
+    private var ans = Int.min
+
+    func maxPathSum(_ root: TreeNode?) -> Int {
+        _ = dfs(root)
+        return ans
+    }
+
+    private func dfs(_ root: TreeNode?) -> Int {
+        guard let root = root else {
+            return 0
+        }
+        let left = max(0, dfs(root.left))
+        let right = max(0, dfs(root.right))
+        ans = max(ans, root.val + left + right)
+        return root.val + max(left, right)
+    }
+}
