# Leetcode: Increasing Order Search Tree

Increasing Order Search Tree

Similar Problems:

Given a tree, rearrange the tree in in-order so that the leftmost node in the tree is now the root of the tree, and every node has no left child and only 1 right child.

Example 1:

```Input: [5,3,6,2,4,null,8,1,null,null,null,7,9]

5
/ \
3    6
/ \    \
2   4    8
/        / \
1        7   9

Output: [1,null,2,null,3,null,4,null,5,null,6,null,7,null,8,null,9]

1
\
2
\
3
\
4
\
5
\
6
\
7
\
8
\
9
```

Note:

1. The number of nodes in the given tree will be between 1 and 100.
2. Each node will have a unique integer value from 0 to 1000.

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.

• Solution:
```// Blog link: https://code.dennyzhang.com/increasing-order-search-tree
// Basic Ideas: in-order
// Complexity: Time O(n), Space O(n)
/**
* Definition for a binary tree node.
* type TreeNode struct {
*     Val int
*     Left *TreeNode
*     Right *TreeNode
* }
*/
Tail *TreeNode
}

if root == nil { return &LinkNode{nil, nil} }
if root.Left == nil && root.Right == nil {
}
l1 := dfs(root.Left)
l2 := dfs(root.Right)

if l1.Tail != nil {
l1.Tail.Right = root
}