Merge pull request #1229 from nprepaci/1448-CountGoodNodesInBinaryTree-Swift

1448-Count Good Nodes in Binary Tree -- SWIFT

Author: dissesmac

swift/1448-Count-Good-Nodes-In-Binary-Tree.swift

@@ -0,0 +1,19 @@
+//
+//  1448-Count-Good-Nodes-In-Binary-Tree.swift
+//  Question Link: https://leetcode.com/problems/count-good-nodes-in-binary-tree/
+//
+
+class Solution {
+    func goodNodes(_ root: TreeNode?) -> Int {
+        guard let root = root else { return 0 }
+        return helper(root, Int.min)
+    }
+    
+    func helper(_ root: TreeNode?, _ lastVal: Int) -> Int {
+        guard let root = root else { return 0 }
+        let i = root.val >= lastVal ? 1 : 0
+        let left = helper(root.left, max(lastVal, root.val))
+        let right = helper(root.right, max(lastVal, root.val))
+        return i + left + right
+    }
+}