leetcode

commit 4c84406024ab796644cd3a53769c52dbf8341811
parent 27248c4b7f20d7884c788fd214243127ce0769df
Author: AndrewLockVI <andrewlaack1@gmail.com>
Date:   Mon, 22 May 2023 12:34:48 -0500

Completed flatten binary tree using DFS, pre-order traversal, recursion, and dart

Diffstat:
A
flatten-binary-tree-to-linked-list/flatten-binary-tree-to-linked-list.dart
 | 
30
++++++++++++++++++++++++++++++

1 file changed, 30 insertions(+), 0 deletions(-)
diff --git a/flatten-binary-tree-to-linked-list/flatten-binary-tree-to-linked-list.dart b/flatten-binary-tree-to-linked-list/flatten-binary-tree-to-linked-list.dart
@@ -0,0 +1,30 @@
+//Given a binary tree the values after performing a preorder
+//traversal and then reorganizing the tree so that the preorder
+//values are all placed on the right side similar to a linked list.
+//To do this I iterated through the tree adding each node to the list
+//as I went (pre-order). I then created a new binary tree reusing the root
+//where each right value was the next value in the list.
+//Time: 285ms Beats: 100%
+//Memory: 143.8MB Beats: 50%
+
+class Solution {
+  List<int> vals = [];
+  void flatten(TreeNode? root) {
+      recurse(root);
+      root?.left = null;
+      TreeNode? itr = root;
+      for(int i = 1 ; i < vals.length ; ++i){
+          itr?.right = new TreeNode(vals[i]);
+          itr = itr?.right;
+      }
+
+  }
+  void recurse(TreeNode? root){
+      if(root == null){
+          return;
+      }
+      vals.add(root.val);
+      recurse(root.left);
+      recurse(root.right);
+  }
+}