Convert a Sorted Doubly Linked List to Balanced BST.

Objective: Given a sorted doubly linked list, convert it into Balanced binary search tree

Input: A Doubly Linked List

Example:

DLL TO BST Example

Approach:

1. Get the size of the Doubly Linked list.
2. Take left n/2 nodes and recursively construct left subtree
3. Make the middle node as root and assign the left subtree( constructed in step 2) to root’s left.
4. Recursively construct right subtree and link it to the the right of root made in step 3.
5. See picture below

Doubly Linked List TO BST – Output

Complete Code:

Output :

DLL is :
1 2 3 4 5 6 7 8 9
Inorder traversal of contructed BST
1 2 3 4 5 6 7 8 9