first commit

Author: imsushant12

LinkedListImp.java

@@ -0,0 +1,178 @@
+public class LinkedListImp {
+
+    Node head;
+    private int size;
+
+    LinkedListImp() {
+        this.size = 0;
+    }
+
+    class Node {
+        int data;
+        Node next;
+
+        // Constructor:
+        Node(int data) {
+            this.data = data;
+            this.next = null;
+            size++;
+        }
+    }
+
+    public void addFirst(int data) {
+        Node newNode = new Node(data);
+
+        if (head == null) {
+            head = newNode;
+            return;
+        }
+
+        newNode.next = head;
+        head = newNode;
+    }
+
+    public void addLast(int data) {
+        Node newNode = new Node(data);
+
+        if (head == null) {
+            head = newNode;
+            return;
+        }
+
+        Node currentNode = head;
+        while (currentNode.next != null) {
+            currentNode = currentNode.next;
+        }
+        currentNode.next = newNode;
+    }
+
+    public void addAfter(int data, int position) {
+        Node newNode = new Node(data);
+
+        if (head == null) {
+            head = newNode;
+            return;
+        }
+
+        if (position > size) {
+            System.out.println("List is smaller than specified position!");
+            return;
+        }
+
+        Node currentNode = head;
+        int currentPosition = 1;
+
+        while (currentPosition != position) {
+            currentNode = currentNode.next;
+            currentPosition++;
+        }
+
+        newNode.next = currentNode.next;
+        currentNode.next = newNode;
+    }
+
+    public void printList() {
+        if (head == null) {
+            System.out.println("The list is empty.");
+        }
+
+        Node currentNode = head;
+
+        while (currentNode != null) {
+            System.out.print(currentNode.data + "  -->  ");
+            currentNode = currentNode.next;
+        }
+        System.out.print("NULL.\n");
+    }
+
+    public void delFirst() {
+        if (head == null) {
+            System.out.println("The list is empty.");
+            return;
+        }
+        size--;
+
+        Node deletedNode = head;
+        head = head.next;
+
+        System.out.println("Deleted: " + deletedNode.data);
+    }
+
+    public void delLast() {
+        if (head == null) {
+            System.out.println("The list is empty.");
+            return;
+        }
+        size--;
+
+        if (head.next == null) {
+            head = null;
+            return;
+        }
+
+        Node deletedNode = head;
+        Node currentNode = head.next;
+
+        while (currentNode.next != null) {
+            currentNode = currentNode.next;
+            deletedNode = deletedNode.next;
+        }
+
+        System.out.println("Deleted: " + deletedNode.next.data);
+        deletedNode.next = null;
+    }
+
+    public void deleteAfter(int position) {
+        if (head == null) {
+            System.out.println("The list is empty.");
+            return;
+        }
+        size--;
+
+        if (position > size) {
+            System.out.println("List is smaller than specified position!");
+            return;
+        }
+
+        Node currentNode = head;
+        int currentPosition = 1;
+
+        while (currentPosition < position-1) {
+            currentNode = currentNode.next;
+            currentPosition++;
+        }
+        Node deletedNode = currentNode.next;
+        currentNode.next = deletedNode.next;
+
+        System.out.println("Deleted: " + deletedNode.data);
+
+    }
+
+    public int getSize() {
+        return size;
+    }
+
+    public static void main(String[] args) {
+        LinkedListImp ll = new LinkedListImp();
+
+        ll.addFirst(10);
+        ll.addFirst(20);
+        ll.addFirst(30);
+        ll.addLast(40);
+        ll.addLast(50);
+        ll.addFirst(11);
+        ll.addLast(60);
+
+        ll.printList();
+        System.out.println(ll.getSize());
+
+        ll.addAfter(65, 2);
+
+        ll.printList();
+        System.out.println(ll.getSize());
+
+        ll.deleteAfter(3);
+        ll.printList();
+        System.out.println(ll.getSize());
+    }
+}