Solving Flatten Binary Tree to Linked List in go. Please try yourself first to solve the problem and submit your implementation to LeetCode before looking into solution.

## Problem Description

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

For example, given the following tree:

``````        1
/ \
2   5
/ \   \
3   4   6``````

The flattened tree should look like:

``````1
\
2
\
3
\
4
\
5
\
6

1
/ \
2   5
/ \   \
3   4   6
-----------
pre = 5
cur = 4

1
/
2
/ \
3   4
\
5
\
6
-----------
pre = 4
cur = 3

1
/
2
/
3
\
4
\
5
\
6
-----------
cur = 2
pre = 3

1
/
2
\
3
\
4
\
5
\
6
-----------
cur = 1
pre = 2

1
\
2
\
3
\
4
\
5
\
6

public void flatten(TreeNode root) {
if (root == null)
return;
flatten(root.right);
flatten(root.left);
}

private TreeNode prev = null;

public void flatten(TreeNode root) {
if (root == null)
return;
flatten(root.right);
flatten(root.left);
root.right = prev;
root.left = null;
prev = root;
}``````

See the full details of the problem Flatten Binary Tree to Linked List at LeetCode

Originally posted at: @github.com/halfrost/LeetCode-Go