hacktoberfest Create dd12

dd12

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+// Java Program to remove duplicates
+// from a sorted linked list
+class GFG
+{
+/* Link list node */
+static class Node
+{
+	int data;
+	Node next;
+};
+
+// The function removes duplicates
+// from a sorted list
+static Node removeDuplicates(Node head)
+{
+	/* Pointer to store the pointer
+	of a node to be deleted*/
+	Node to_free;
+
+	/* do nothing if the list is empty */
+	if (head == null)
+		return null;
+
+	/* Traverse the list till last node */
+	if (head.next != null)
+	{
+
+		/* Compare head node with next node */
+		if (head.data == head.next.data)
+		{
+			/* The sequence of steps is important.
+			to_free pointer stores the next of head
+			pointer which is to be deleted.*/
+			to_free = head.next;
+			head.next = head.next.next;
+			removeDuplicates(head);
+		}
+
+		/* This is tricky: only advance if no deletion */
+		else
+		{
+			removeDuplicates(head.next);
+		}
+	}
+	return head;
+}
+
+/* UTILITY FUNCTIONS */
+/* Function to insert a node at the beginning
+of the linked list */
+static Node push(Node head_ref,
+				int new_data)
+{
+	/* allocate node */
+	Node new_node = new Node();
+
+	/* put in the data */
+	new_node.data = new_data;
+
+	/* link the old list off the new node */
+	new_node.next = (head_ref);	
+
+	/* move the head to point to the new node */
+	(head_ref) = new_node;
+	return head_ref;
+}
+
+/* Function to print nodes in a given linked list */
+static void printList(Node node)
+{
+	while (node != null)
+	{
+		System.out.print(" " + node.data);
+		node = node.next;
+	}
+}
+
+/* Driver code*/
+public static void main(String args[])
+{
+	/* Start with the empty list */
+	Node head = null;
+
+	/* Let us create a sorted linked list
+	to test the functions
+	Created linked list will be 11.11.11.13.13.20 */
+	head = push(head, 20);
+	head = push(head, 13);
+	head = push(head, 13);
+	head = push(head, 11);
+	head = push(head, 11);
+	head = push(head, 11);									
+
+	System.out.println("Linked list before" +
+					" duplicate removal ");
+	printList(head);
+
+	/* Remove duplicates from linked list */
+	head = removeDuplicates(head);
+
+	System.out.println("\nLinked list after" +
+					" duplicate removal ");	
+	printList(head);			
+}
+}
+
+// This code is contributed by Arnab Kundu