Remove duplicates from an unsorted linked list Java

PROGRAM TO REMOVE DUPLICATES FROM A SORTED LINKED LIST

import java.util.HashSet;

 

public class removeDuplicates

{

    static class node

    {

        int val;

        node next;

 

        public node(int val)

        {

            this.val = val;

        }

    }

     

    /* Function to remove duplicates from a

       unsorted linked list */

    static void removeDuplicate(node head)

    {

        // Hash to store seen values

        HashSet<Integer> hs = new HashSet<>();

     

        /* Pick elements one by one */

        node current = head;

        node prev = null;

        while (current != null)

        {

            int curval = current.val;

             

             // If current value is seen before

            if (hs.contains(curval)) {

                prev.next = current.next;

            } else {

                hs.add(curval);

                prev = current;

            }

            current = current.next;

        }

 

    }

     

    /* Function to print nodes in a given linked list */

    static void printList(node head)

    {

        while (head != null)

        {

            System.out.print(head.val + " ");

            head = head.next;

        }

    }

 

    public static void main(String[] args)

    {

        /* The constructed linked list is:

         10->12->11->11->12->11->10*/

        node start = new node(10);

        start.next = new node(12);

        start.next.next = new node(11);

        start.next.next.next = new node(11);

        start.next.next.next.next = new node(12);

        start.next.next.next.next.next = new node(11);

        start.next.next.next.next.next.next = new node(10);

 

        System.out.println("Linked list before removing duplicates :");

        printList(start);

 

        removeDuplicate(start);

 

        System.out.println("\nLinked list after removing duplicates :");

        printList(start);

    }

}




OUTPUT

Linked list before removing duplicates:
 10 12 11 11 12 11 10 
Linked list after removing duplicates:
 10 12 11

CREDITS: https://www.geeksforgeeks.org/remove-duplicates-from-an-unsorted-linked-list/