Java Day 24: More Linked Lists

A Node class is provided for you in the editor. A Node object has an integer data field, data, and a Node instance pointer, next, pointing to another node (i.e.: the next node in a list).

A removeDuplicates function is declared in your editor, which takes a pointer to the head node of a linked list as a parameter. Complete removeDuplicates so that it deletes any duplicate nodes from the list and returns the head of the updated list.

Note: The head+ pointer may be null, indicating that the list is empty. Be sure to reset your next pointer when performing deletions to avoid breaking the list.



  1. import java.io.*;

  2. import java.util.*;

  3. class Node{

  4. 	int data;

  5. 	Node next;

  6. 	Node(int d){

  7.         data=d;

  8.         next=null;

  9.     }

  10. 	

  11. }

  12. class Solution

  13. {

  14. 

  15.     public static Node removeDuplicates(Node head) {

  16.         Node curr = head;

  17.         while (curr != null && curr.next != null) {

  18.             while (curr.next != null && curr.data == curr.next.data) {

  19.                 curr.next = curr.next.next;

  20.             }

  21.             curr = curr.next;

  22.         }

  23.         return head;

  24.     }

  25. 

  26. 

  27.     public static  Node insert(Node head,int data)

  28.     {

  29.         Node p=new Node(data);			

  30.         if(head==null)

  31.             head=p;

  32.         else if(head.next==null)

  33.             head.next=p;

  34.         else

  35.         {

  36.             Node start=head;

  37.             while(start.next!=null)

  38.                 start=start.next;

  39.             start.next=p;

  40. 

  41.         }

  42.         return head;

  43.     }

  44.     public static void display(Node head)

  45.         {

  46.               Node start=head;

  47.               while(start!=null)

  48.               {

  49.                   System.out.print(start.data+" ");

  50.                   start=start.next;

  51.               }

  52.         }

  53.         public static void main(String args[])

  54.         {

  55.               Scanner sc=new Scanner(System.in);

  56.               Node head=null;

  57.               int T=sc.nextInt();

  58.               while(T-->0){

  59.                   int ele=sc.nextInt();

  60.                   head=insert(head,ele);

  61.               }

  62.               head=removeDuplicates(head);

  63.               display(head);

  64. 

  65.        }

  66.     }
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