feat: add swift implementation to lcp problem: No.34 (#3780)

Author: klever34

lcp/LCP 34. 二叉树染色/README.md

@@ -225,6 +225,49 @@ var maxValue = function (root, k) {
 };
 ```
 
+#### Swift
+
+```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 {
+    private var k: Int = 0
+    
+    func maxValue(_ root: TreeNode?, _ k: Int) -> Int {
+        self.k = k
+        return dfs(root).max() ?? 0
+    }
+    
+    private func dfs(_ root: TreeNode?) -> [Int] {
+        var ans = [Int](repeating: 0, count: k + 1)
+        guard let root = root else {
+            return ans
+        }
+        let l = dfs(root.left)
+        let r = dfs(root.right)
+        
+        ans[0] = (l.max() ?? 0) + (r.max() ?? 0)
+        
+        for i in 0..<k {
+            for j in 0..<k - i {
+                ans[i + j + 1] = max(ans[i + j + 1], root.val + l[i] + r[j])
+            }
+        }
+        return ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

lcp/LCP 34. 二叉树染色/Solution.swift

@@ -0,0 +1,38 @@
+/* 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 {
+    private var k: Int = 0
+    
+    func maxValue(_ root: TreeNode?, _ k: Int) -> Int {
+        self.k = k
+        return dfs(root).max() ?? 0
+    }
+    
+    private func dfs(_ root: TreeNode?) -> [Int] {
+        var ans = [Int](repeating: 0, count: k + 1)
+        guard let root = root else {
+            return ans
+        }
+        let l = dfs(root.left)
+        let r = dfs(root.right)
+        
+        ans[0] = (l.max() ?? 0) + (r.max() ?? 0)
+        
+        for i in 0..<k {
+            for j in 0..<k - i {
+                ans[i + j + 1] = max(ans[i + j + 1], root.val + l[i] + r[j])
+            }
+        }
+        return ans
+    }
+}