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| 1 | +public class LinkedList { |
| 2 | + public class Node{ |
| 3 | + String data; |
| 4 | + Node next; |
| 5 | + |
| 6 | + Node(String data){ |
| 7 | + this.data = data; |
| 8 | + this.next = null; |
| 9 | + size ++; |
| 10 | + } |
| 11 | + } |
| 12 | + |
| 13 | + Node head; |
| 14 | + |
| 15 | + int size; |
| 16 | + |
| 17 | + LinkedList(){ |
| 18 | + this.size = 0; |
| 19 | + } |
| 20 | + |
| 21 | + public void addNodeAtFirst(String data){ |
| 22 | + Node newNode = new Node(data); |
| 23 | + if (head == null){ |
| 24 | + head = newNode; |
| 25 | + return; |
| 26 | + } |
| 27 | + newNode.next = head; |
| 28 | + head = newNode; |
| 29 | + } |
| 30 | + |
| 31 | + public void addNodeAtLast(String data){ |
| 32 | + Node newNode = new Node(data); |
| 33 | + if (head == null){ |
| 34 | + head = newNode; |
| 35 | + return; |
| 36 | + } |
| 37 | + Node currentNode = head; |
| 38 | + while (currentNode.next != null){ |
| 39 | + currentNode = currentNode.next; |
| 40 | + } |
| 41 | + currentNode.next= newNode; |
| 42 | + } |
| 43 | + |
| 44 | + public void deleteFromFirst(){ |
| 45 | + if (head == null){ |
| 46 | + System.out.println("The List is empty, Nothing to delete here"); |
| 47 | + return; |
| 48 | + } |
| 49 | + size--; |
| 50 | + head = head.next; |
| 51 | + } |
| 52 | + |
| 53 | + public void deleteFromLast(){ |
| 54 | + if (head == null){ |
| 55 | + System.out.println("The List is empty, Nothing to delete here"); |
| 56 | + return; |
| 57 | + } |
| 58 | + size--; |
| 59 | + if (head.next == null){ |
| 60 | + head=null; |
| 61 | + return; |
| 62 | + } |
| 63 | + Node secondLast = head; |
| 64 | + Node lastNode = head.next; |
| 65 | + while (lastNode.next != null){ |
| 66 | + lastNode= lastNode.next; |
| 67 | + secondLast = secondLast.next; |
| 68 | + } |
| 69 | + secondLast.next = null; |
| 70 | + } |
| 71 | + |
| 72 | + public void reverse(){ |
| 73 | + if (head== null || head.next == null){ |
| 74 | + return; |
| 75 | + } |
| 76 | + Node prevNode = head; |
| 77 | + Node currentNode = head.next; |
| 78 | + while (currentNode!= null){ |
| 79 | + Node nextNode = currentNode.next; |
| 80 | + currentNode.next = prevNode; |
| 81 | + prevNode = currentNode; |
| 82 | + currentNode = nextNode; |
| 83 | + } |
| 84 | + head.next=null; |
| 85 | + head= prevNode; |
| 86 | + } |
| 87 | + |
| 88 | + public Node reserveLL(Node head){ |
| 89 | + if (head == null){ |
| 90 | + return null; |
| 91 | + } |
| 92 | + Node newHead= reserveLL(head.next); |
| 93 | + head.next.next = head; |
| 94 | + head.next=null; |
| 95 | + return newHead; |
| 96 | + } |
| 97 | + |
| 98 | + public int getSize(){ |
| 99 | + return size; |
| 100 | + } |
| 101 | + |
| 102 | + public void printList(){ |
| 103 | + if (head == null){ |
| 104 | + System.out.println("List is Empty"); |
| 105 | + return; |
| 106 | + } |
| 107 | + Node currentNode = head; |
| 108 | + while (currentNode!= null){ |
| 109 | + System.out.print(currentNode.data + " --> "); |
| 110 | + currentNode = currentNode.next; |
| 111 | + } |
| 112 | + System.out.println("Null"); |
| 113 | + } |
| 114 | + |
| 115 | + public static void main(String[] args) { |
| 116 | + LinkedList list = new LinkedList(); |
| 117 | + list.addNodeAtFirst("is"); |
| 118 | + list.addNodeAtLast("Kartik"); |
| 119 | + list.addNodeAtFirst("name"); |
| 120 | + list.addNodeAtFirst("My"); |
| 121 | + list.printList(); |
| 122 | + list.addNodeAtLast("Sharma"); |
| 123 | + list.printList(); |
| 124 | + list.deleteFromFirst(); |
| 125 | + list.printList(); |
| 126 | + list.deleteFromLast(); |
| 127 | + list.printList(); |
| 128 | + list.deleteFromLast(); |
| 129 | + list.deleteFromFirst(); |
| 130 | + |
| 131 | + list.printList(); |
| 132 | + list.deleteFromFirst(); |
| 133 | + |
| 134 | + list.printList(); |
| 135 | + list.deleteFromFirst(); |
| 136 | + |
| 137 | + System.out.println(list.getSize()); |
| 138 | + |
| 139 | + list.addNodeAtLast("The"); |
| 140 | + System.out.println(list.getSize()); |
| 141 | + list.printList(); |
| 142 | + list.addNodeAtLast("Ram"); |
| 143 | + list.addNodeAtFirst("Shyam"); |
| 144 | + list.addNodeAtFirst("is"); |
| 145 | + list.printList(); |
| 146 | + list.reverse(); |
| 147 | + list.printList(); |
| 148 | + list.reserveLL(list.head); |
| 149 | + } |
| 150 | + |
| 151 | +} |
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