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  1. /**
  2.  * Linked List Node
  3.  * @author Prateek
  4.  */
  5. class Node {
  6.  
  7. 	public int data;
  8. 	public Node next;
  9. 	public Node prev;
  10.  
  11. 	public Node(int data){
  12. 		this.data=data;
  13. 	}
  14.  
  15. 	public String toString(){
  16. 		return ""+data;
  17. 	}
  18. }
  19.  
  20. /**
  21.  * Swap pair wise node using Iteration
  22.  * @author Prateek
  23.  */
  24. class PairSwapIterative {
  25.  
  26. 	/**
  27. 	 * Iterative Subroutine to swap pairs of nodes of linked list
  28. 	 * @return new Head of the linked list
  29. 	 */
  30. 	public Node pairSwap(Node head){
  31. 		Node temp=head;
  32. 		head=head.next; //new head
  33.  
  34. 		Node front,back;
  35. 		while(temp!=null && temp.next!=null)
  36. 		{
  37. 			back=temp;
  38. 			front=temp.next;
  39.  
  40. 			back.next=front.next;
  41. 			front.next=back;
  42.  
  43. 			if(temp.next!=null)
  44. 				temp=temp.next;
  45. 			if(temp.next!=null)
  46. 				back.next=temp.next;
  47. 		}
  48. 		return head;
  49. 	}
  50.  
  51. 	public static void main(String[] args) {
  52. 		PairSwapIterative obj = new PairSwapIterative() ;
  53.  
  54. 		Node root = new Node(1) ;
  55. 		root.next =new Node(2) ;
  56. 		root.next.next =new Node(3) ;
  57. 		root.next.next.next =new Node(4) ;
  58. 		root.next.next.next.next =new Node(5) ;
  59. 		//root.next.next.next.next.next =new Node(6) ;
  60.  
  61. 		Node head=obj.pairSwap(root);
  62. 		obj.display(head);
  63. 	}
  64.  
  65. 	/**
  66. 	 * Display the nodes of the linked list
  67. 	 */
  68. 	public void display(Node root)	{
  69. 		Node tempNode;
  70. 		tempNode=root;
  71. 		while(tempNode!=null){
  72. 			System.out.print(tempNode.data+"-->");
  73. 			tempNode=tempNode.next;
  74. 		}
  75. 		System.out.print("null");
  76. 		System.out.println();
  77. 	}
  78.  
  79. }
  80.  
Success #stdin #stdout 0.07s 380224KB
comments (?)
stdin 
Standard input is empty
stdout 
2-->1-->4-->3-->5-->null
https://ideone.com/2s13x0
Pair Swapping (Iterative) Linked List
language:
Java (HotSpot 12)
created:
10 years ago
visibility:
public

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