Sort a linked list of 0,1 and 2's - count 0, 1 and 2's.

LinkedList012Sort.java

// So we create there list, one each for 0, 1 and 2.
// The head of each of these point to the 0, 1 and 2, node in the main list given.
// while travesing we point head0 to first node with 0, the next of which points to next node with 0 and it goes on.
// similarly for 1 and 2.
//  in the end we add head2 at end of head1. n then add head1 to end of head0.
// ignore the crappy naming convention. It's jsut a POC that it can be done this way. GeeksForGeek does not has this solution

class Node {
    
    int data;
    Node next;
    
    Node(int d)  
    { 
        data = d;  
        next = null; 
    } 
}

class LinkedList
{
    Node head;  // head of list
 
    /* This function prints contents of linked list starting from head */
    public void printList()
    {
        Node temp = head;
        System.out.println( " Print Function: ");
        while (temp != null)
        {
            System.out.println("Data: " + temp.data);
            temp = temp.next;
        }
        System.out.println();
    }
    
    public void create()
    {
        Node head0 = null;
        Node head1 = null;
        Node head2 = null;
        Node f     = null;
        Node node0 = null;
        Node node1 = null;
        Node node2 = null;
        
        Node temp = this.head;
        while (temp!=null)
        {
           if (temp.data == 0) 
           {
             if(head0 == null)   
             {
                node0 = new Node(0);
                head0 = node0;
                node0.next = null;
                 
             } 
             else
             {
                 node0 = new Node(0);
                 f = head0;
                 while(f.next!=null)
                 {
                     f = f.next;
                 }
                 f.next = node0;
             }
           }
           else if(temp.data == 1)
           {
             if(head1 == null)   
             {
                node1 = new Node(1);
                head1 = node1;
                node1.next = null;
                 
             } 
             else
             {
                 node1 = new Node(1);
                 f = head1;
                 while(f.next!=null)
                 {
                     f = f.next;
                 }
                 f.next = node1;
             }
           }
           else if(temp.data == 2)
           {
             if(head2 == null)   
             {
                node2 = new Node(2);
                head2 = node2;
                node2.next = null;
                 
             } 
             else
             {
                 node2 = new Node(2);
                 f = head2;
                 while(f.next!=null)
                 {
                     f = f.next;
                 }
                 f.next = node2;
             }
           }
           temp = temp.next;
        }
        
        Node loop0 = head0;
        while(loop0.next!=null)
        {
            loop0 = loop0.next;
        }
        loop0.next = head1;
        
        loop0 = head0;
        while(loop0.next!=null)
        {
            loop0 = loop0.next;
        }
        loop0.next = head2;
        
        
        loop0 = head0;
        while(loop0!=null)
        {
            System.out.println(loop0.data);
            loop0 = loop0.next;
        }
    }
        
    public static void main(String[] args)
    {
        LinkedList llist = new LinkedList();
        llist.head   = new Node(0);
        Node second  = new Node(2);
        Node third   = new Node(1);
        Node fourth  = new Node(2);
        Node fifth   = new Node(2);
        llist.head.next = second;
        second.next = third;
        third.next  = fourth;
        fourth.next = fifth;
        llist.printList();
        llist.create();
        
    }

    public void addAtHead(int data)
    {
        Node node  = new Node(data);
        node.next  = this.head;
        this.head  = node;
    }
}