**Objective:** Write a program to remove the duplicates from an unsorted linked list

**Example: **

Input Linked List : 1->2->2->4->3->3->2 Output : 1->2->4->3

**Input:** An unsorted linked list

**Output: Linked list with no duplicates.**

**Approach: **

- Create a Hash Map
- Take two pointers, prevNode and CurrNode.
- PrevNode will point to the head of the linked list and currNode will point to the head.next.

- Now navigate through the linked list.
- Check every node data is present in the Hash Map.
- if yes then delete that node using prevNode and currNode.
- If No, then insert that node data into the Hash Map.
- Return the head of the list

Time Complexity : O(n)

Space Complexity : O(n)

**Follow Up**: If suppose addition buffer is not allowed then we have option but to check every node data against every other node data and if find duplicates, delete that node.

**Time Complexity** : O(n^2)

**Complete Code for the Hash Table method:**

**Output**:

Original List : ->1->2->2->3->4->4->2 Updated List: ->1->2->3->4