leetcode

commit d5d4fad717c416c1586c24d3b277d72518ca8924
parent 7760d9501adef9876c9ddaf7ca025ab7f47f4c55
Author: AndrewLockVI <andrewlaack1@gmail.com>
Date:   Wed, 10 May 2023 21:00:24 -0500

Completed binary tree preorder traversal problem using dart

Diffstat:
A
binary-tree-preeorder-traversal/preorder-traversal.dart
 | 
26
++++++++++++++++++++++++++

1 file changed, 26 insertions(+), 0 deletions(-)
diff --git a/binary-tree-preeorder-traversal/preorder-traversal.dart b/binary-tree-preeorder-traversal/preorder-traversal.dart
@@ -0,0 +1,26 @@
+//Return the preordered list of a binary tree.
+//A preorder of a tree is the root then the next 
+//node on the left and so on until the bottom until you
+//return the right and so on.
+//The time complexity of this code is O(n) where n is the number
+//of nodes.
+//Time: 264ms Beats: 50%
+//Memory: 142.4MB Beats: 10%
+class Solution {
+  List<int> vals = [];
+  List<int> preorderTraversal(TreeNode? root) {
+      recurse(root);
+      return vals;
+  }
+
+  void recurse(TreeNode? root){
+      if(root == null){
+          return;
+      }
+      vals.add((root?.val ?? 0));
+      recurse(root?.left);
+      recurse(root?.right);
+
+
+  }
+}