Flattening Linked List

Java Programs/LinkedList.java

@@ -0,0 +1,168 @@
+import java.util.Scanner;
+public class LinkedList
+{
+	 static Scanner in=new Scanner(System.in);
+	 Node p=null;
+
+	 //CREATING A VERTICALLY LINKED LIST
+	 public static Node pushdown(Node p, int key)
+	 {
+	     Node newNode = new Node();
+	     newNode.data = key;
+	     //newNode.next = null;
+	     newNode.down=p;
+	     return newNode; //RETURNS EACH NODE CREATED
+	  }
+
+	  //INSERTION OF ALL ELEMENTS INTO A SINGLE FLATTENED LIST
+	  void Insert(int value)
+	  {
+		  Node newnode = new Node();
+		  newnode.data=value;
+		  newnode.next=null;
+		  newnode.next=p;
+		  p=newnode;
+	  }
+
+	 //FLATTENING OF LL- TRAVERSAL HAPPENS IN BOTH DIRECTIONS
+	 //GOES TO EACH HEAD NODE AND ADDS THE SUBSEQUENT NODE(ELEMENT(S)) IN THE VERTICAL LIST TO THE FLATTENED LIST
+	 void flatten(Node root)
+	 {
+		 Node hor=root;
+			 while(hor!=null)
+			 {
+				 Node ver=hor;
+				 while(ver!=null)
+				 {
+					 Insert(ver.data);
+					 ver=ver.down;//TRAVERSING OF VERTICAL LIST
+				 }
+				 hor=hor.next;//HORIZONTAL MOVEMENT-MAIN LIST TRAVERSAL
+			 }
+	  }
+
+	  void ll_test(Node root)
+	  {
+		  Node hor=root,temp;
+		  temp=hor;
+		  while(temp!=null)
+		  {
+			  System.out.print(temp.data+"\t");
+			  temp=temp.next;
+		  }
+		  System.out.println();
+
+		  while(hor!=null)
+			 {
+				 Node ver=hor;
+				 while(ver!=null)
+				 {
+					System.out.print(ver.data+"\t");
+					 ver=ver.down;
+				 }System.out.println();
+				 hor=hor.next;//HORIZONTAL MOVEMENT
+			 }
+	 }
+
+	 //SORTING OF THE FLATTENED LIST
+	 void sort_ll()
+	 {
+		 Node current=null,Next=null;
+		 int temp;
+		 current=p;
+		 if(p==null)
+		 {
+			 System.out.println("EMPTY");
+		 }
+		 else
+		 {
+			 while(current!=null)
+			 {
+				 Next=current.next;
+				 while(Next!=null)
+				 {
+					 while(current.data>Next.data)
+					 {
+						 temp=current.data;
+						 current.data=Next.data;
+						 Next.data=temp;
+					 }
+					 Next=Next.next;
+				 }
+				 current=current.next;
+			 }
+		 }
+	 }
+
+	 void traversal()
+	 {
+		if(p==null)
+	    {
+	        System.out.println("LIST IS EMPTY");
+	    }
+	    else
+	    {
+	        Node temp=p;
+	        System.out.print(temp.data);
+	        while(temp.next!=null)
+	        {
+	        	//System.out.print(temp.data+"-->");
+	            temp=temp.next;
+	            System.out.print("-->"+temp.data);
+
+	         }
+	    }
+	    System.out.println();
+	  }
+
+	  //METHOD TO CREATE VERTICAL LIST
+	  public Node createVerticalList(Node head, int[] arr)
+	  {
+	     for (int key: arr) //GOES THROUGH EACH ELEMENT
+	     {
+	        head = pushdown(head, key);
+	     }
+	     return head;//RETURNS HEAD OF THE MAIN LIST
+	  } 
+
+	  //A METHOD TO INPUT ELEMENTS FOR THE LIST IN THE FORM OF AN ARRAY
+	  void inputArray(int arr[],int size)
+	  {
+		 int ele;
+		 for(int i=size-1;i>=0;i--)
+		 {
+			 ele=in.nextInt();
+			 arr[i]=ele;
+		 }
+		 System.out.println();
+	  }
+
+	  public static void main(String[] args)
+	  {
+		    Node head = null;
+			LinkedList l= new LinkedList();
+
+		    int[] arr1 = new int[4];
+	        int[] arr2 = new int[4];
+	        int[] arr3 = new int[3];
+	        int[] arr4 = new int[2];
+
+	        l.inputArray(arr1, 4);
+	        l.inputArray(arr2, 4);
+	        l.inputArray(arr3, 3);
+	        l.inputArray(arr4, 2);
+
+		    //LINKING LIST VERTICALLY
+	        System.out.println();
+	        head = l.createVerticalList(head, arr1);
+	        head.next = l.createVerticalList(head.next, arr2);
+	        head.next.next = l.createVerticalList(head.next.next, arr3);
+	        head.next.next.next = l.createVerticalList(head.next.next.next, arr4);
+
+	        l.flatten(head);
+	        l.sort_ll();
+	        l.ll_test(head);
+	        System.out.println();
+	        l.traversal();
+	}
+}