C# solution for Leetcode question: Flatten Binary Tree to Linked List (difficulty : medium)

Source:

Given a binary tree, flatten it to a linked list in-place.

For example,
 Given

1
/ \
2 5
/ \ \
3 4 6

The flattened tree should look like:

1
\
2
\
3
\
4
\
5
\
6

Hints:

If you notice carefully in the flattened tree, each node’s right child points to the next node of a pre-order traversal.

My C# solution is here:

https://github.com/jiajionline/LeetcodeSolutionWithMultipleLanguages/tree/master/Flatten%20Binary%20Tree%20to%20Linked%20List