1305_All_Elements_in_Two_Binary_Search_Trees

Author: Partho Biswas

README.md

@@ -463,6 +463,7 @@ Check this [golden](https://tinyurl.com/ujopecz) post.
 |39| [1315. Sum of Nodes with Even-Valued Grandparent](https://tinyurl.com/y72q6hfn) | [Python](https://tinyurl.com/wu6rdaw/1315_Sum_of_Nodes_with_Even_Valued_Grandparent.py), [Swift](https://tinyurl.com/wuja3c4/1315_Sum_of_Nodes_with_Even_Valued_Grandparent.swift) | -- | Medium | -- |
 |40| [129. Sum Root to Leaf Numbers](https://tinyurl.com/yaxakdfs) | [Python](https://tinyurl.com/wu6rdaw/129_Sum_Root_to_Leaf_Numbers.py), [Swift](https://tinyurl.com/wuja3c4/129_Sum_Root_to_Leaf_Numbers.swift) | -- | Medium | -- |
 |41| [938. Range Sum of BST](https://tinyurl.com/r43zu3p) | [Python](https://tinyurl.com/wu6rdaw/938_Range_Sum_of_BST.py), [Swift](https://tinyurl.com/wuja3c4/938_Range_Sum_of_BST.swift) | -- | Medium | -- |
+|42| [1305. All Elements in Two Binary Search Trees](https://tinyurl.com/undhmra) | [Python](https://tinyurl.com/wu6rdaw/1305_All_Elements_in_Two_Binary_Search_Trees.py), [Swift](https://tinyurl.com/wuja3c4/1305_All_Elements_in_Two_Binary_Search_Trees.swift) | -- | Medium | -- |
 
 </p>
 </details>

leetcode.com/swift/DS_ALGO_PRAC.playground/Sources/swift/1305_All_Elements_in_Two_Binary_Search_Trees.swift

@@ -0,0 +1,45 @@
+import Foundation
+
+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
+    }
+}
+
+// Iterative inorder DFS
+class Solution {
+    func getAllElements(_ root1: TreeNode?, _ root2: TreeNode?) -> [Int] {
+        var (result, stack1, stack2) = ([Int](), [TreeNode](), [TreeNode]())
+        var (currentNode1, currentNode2) = (root1, root2)
+        
+        while (!stack1.isEmpty || currentNode1 != nil) || (!stack2.isEmpty || currentNode2 != nil) {
+            while let node1 = currentNode1 {
+                stack1.append(node1)
+                currentNode1 = node1.left
+            }
+            
+            while let node2 = currentNode2 {
+                stack2.append(node2)
+                currentNode2 = node2.left
+            }
+            
+            if stack2.isEmpty || !stack1.isEmpty && (stack2.last!.val >= stack1.last!.val) {
+                currentNode1 = stack1.removeLast()
+                result.append(currentNode1!.val)
+                currentNode1 = currentNode1!.right
+            } else {
+                currentNode2 = stack2.removeLast()
+                result.append(currentNode2!.val)
+                currentNode2 = currentNode2!.right
+            }
+        }
+        return result
+    }
+}