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Remove Duplicates from an Unsorted Linked list
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 an option to check every node data against every other node data and if find duplicates, delete that node.
Time Complexity: O(n^2)
Code:
Original List : >1>2>2>3>4>4>2 Updated List: >1>2>3>4
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