Flatten Binary Tree to Linked List

Given the root of a binary tree, flatten the tree into a "linked list": The "linked list" should use the same TreeNode class where the right child pointer points to the next node in the list and the left child pointer is always null. The "linked list" should be in the same order as a pre-order traversal of the binary tree.

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Flatten Binary Tree to Linked List

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Given the root of a binary tree, flatten the tree into a "linked list": The "linked list" should use the same TreeNode class where the right child pointer points to the next node in the list and the left child pointer is always null. The "linked list" should be in the same order as a pre-order traversal of the binary tree.

Example 1:

Input: {"root":[1,2,5,3,4,null,6]}

Output: [1,null,2,null,3,null,4,null,5,null,6]

Constraints:

The number of nodes is in the range $[0, 2000]$ .
$-100 \leq \text{Node.val} \leq 100$

Input

arr ={"root":[1,2,5,3,4,null,6]}

1

2

5

3

4

6

Variables

Variable	Value
curr	1

DepthFunction Call

Stack empty

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