Create jva.java

jva.java

@@ -0,0 +1,120 @@
+class DeleteMid {  
+
+    //Represent a node of the doubly linked list  
+
+    class Node{  
+        int data;  
+        Node previous;  
+        Node next;  
+
+        public Node(int data) {  
+            this.data = data;  
+        }  
+    }  
+
+    public int size = 0;  
+    //Represent the head and tail of the doubly linked list  
+    Node head, tail = null;  
+
+    //addNode() will add a node to the list  
+    public void addNode(int data) {  
+        //Create a new node  
+        Node newNode = new Node(data);  
+
+        //If list is empty  
+        if(head == null) {  
+            //Both head and tail will point to newNode  
+            head = tail = newNode;  
+            //head's previous will point to null  
+            head.previous = null;  
+            //tail's next will point to null, as it is the last node of the list  
+            tail.next = null;  
+        }  
+        else {  
+            //newNode will be added after tail such that tail's next will point to newNode  
+            tail.next = newNode;  
+            //newNode's previous will point to tail  
+            newNode.previous = tail;  
+            //newNode will become new tail  
+            tail = newNode;  
+            //As it is last node, tail's next will point to null  
+            tail.next = null;  
+        }  
+        //Size will count the number of nodes present in the list  
+        size++;  
+    }  
+
+    //deleteFromMid() will delete a node from middle of the list  
+    public void deleteFromMid() {  
+        //Checks whether list is empty  
+        if(head == null) {  
+            return;  
+        }  
+        else {  
+            //current will point to head  
+            Node current = head;  
+
+            //Store the mid position of the list  
+            int mid = (size % 2 == 0) ? (size/2) : ((size+1)/2);  
+
+            //Iterate through list till current points to mid position  
+            for(int i = 1; i < mid; i++){  
+                current = current.next;  
+            }  
+
+            //If middle node is head of the list  
+            if(current == head) {  
+                head = current.next;  
+            }  
+            //If middle node is tail of the list  
+            else if(current == tail) {  
+                tail = tail.previous;  
+            }  
+            else {  
+                current.previous.next = current.next;  
+                current.next.previous = current.previous;  
+            }  
+            //Delete the middle node  
+            current = null;  
+        }  
+        size--;  
+    }  
+
+    //display() will print out the nodes of the list  
+    public void display() {  
+        //Node current will point to head  
+        Node current = head;  
+        if(head == null) {  
+            System.out.println("List is empty");  
+            return;  
+        }  
+        while(current != null) {  
+            //Prints each node by incrementing the pointer.  
+
+            System.out.print(current.data + " ");  
+            current = current.next;  
+        }  
+        System.out.println();  
+    }  
+
+    public static void main(String[] args) {  
+
+        DeleteMid dList = new DeleteMid();  
+        //Add nodes to the list  
+        dList.addNode(1);  
+        dList.addNode(2);  
+        dList.addNode(3);  
+        dList.addNode(4);  
+        dList.addNode(5);  
+
+        //Printing original list  
+        System.out.println("Original List: ");  
+        dList.display();  
+        while(dList.head != null) {  
+            dList.deleteFromMid();  
+            //Printing updated list  
+            System.out.println("Updated List: ");  
+            dList.display();  
+        }  
+    }  
+}