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  1. class Node {
  2.  
  3. 	public Node prev;
  4. 	public int data;
  5. 	public Node next;
  6.  
  7. 	public Node(int data)	{
  8. 		this.data=data;
  9. 	}
  10.  
  11. 	public String toString(){
  12. 		return ""+this.data ;
  13. 	}
  14. }
  15. /**
  16.  * Reverse Linked List(recursively)
  17.  * @author Prateek
  18.  */
  19.  class ReverseList {
  20.  
  21. 	/**
  22. 	 * Reverse Linked List (recursively) 
  23. 	 * @param head
  24. 	 * @return
  25. 	 */
  26.    public Node reverse(Node head){
  27. 	   Node revHead ; // to store the new Head pointer
  28.  
  29. 	   if( head== null || head.next==null ) 
  30. 		   return head;
  31.  
  32. 	   revHead=reverse(head.next) ;
  33.  
  34. 	   head.next.next = head; // points to itself to create loop
  35. 	   head.next = null;      // breaks the loop (old link)
  36.  
  37. 	   return revHead ;
  38.    }
  39.  
  40.    public static void main(String[] args) {
  41. 	   //   1 -> 2 - > 3 -> 4 -> NUll
  42. 		ReverseList obj = new ReverseList() ;
  43. 		Node root = new Node(1) ;
  44. 		root.next =new Node(2) ;
  45. 		root.next.next =new Node(3) ;
  46. 		root.next.next.next =new Node(4) ;
  47.  
  48. 		System.out.println("Original List :");
  49. 		obj.display(root);
  50.  
  51. 		System.out.println("\n\nReversed List :");
  52. 		obj.display(obj.reverse(root)) ;
  53.  
  54. 	}
  55.  
  56.    private void display(Node head) {
  57. 	 Node temp = head ;
  58. 	 while(temp!=null) {
  59. 		 System.out.print(temp + "\t");
  60. 		 temp=temp.next ;
  61. 	 }
  62.    }
  63. }
  64.  
Success #stdin #stdout 0.06s 381184KB
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Standard input is empty
stdout
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Original List :
1	2	3	4	

Reversed List :
4	3	2	1
https://ideone.com/M1GwdI
language:
Java (12.0.1)
created:
10 years ago
visibility:
secret

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