Question

Java Language

Add a method (convertToRing ()) that converts the list to a circular. This is,
which makes the last node instead of pointing to null point to the first.

Code:

class Node {

int value;

Node nextNode;

Node(int v, Node n)

{

value = v;

nextNode = n;

}

Node (int v)

{

this(v,null);

}

}

class LinkedList

{

Node head; //head = null;

LinkedList()

{

}

int length()

{

Node tempPtr;

int result = 0;

tempPtr = head;

while (tempPtr != null)

{

tempPtr = tempPtr.nextNode;

result = result + 1;

}

return(result);

}

void insertAt(int v, int position)

{

Node newNode = new Node(v,null);

Node tempPtr;

int tempPosition = 0;

if((head == null) || (position ==0))

{

newNode.nextNode = head;

head = newNode;

}

else {

tempPtr = head;

while((tempPtr.nextNode != null)&&(tempPosition < position -1))

{

tempPtr = tempPtr.nextNode;

tempPosition = tempPosition + 1;

}

if (tempPosition == (position - 1))

{

newNode.nextNode = tempPtr.nextNode;

tempPtr.nextNode = newNode;

}

}

}

public String toString()

{

Node tempPtr;

tempPtr = head;

String result = "";

while(tempPtr != null)

{

result = result + "[" + tempPtr.value + "| ]-->";

tempPtr = tempPtr.nextNode;

}

result = result + "null";

return result;

}

}

public class LinkedListDemoInsDel

{

public static void main(String[] args)

{

LinkedList aLinkedList = new LinkedList();

aLinkedList.insertAt(1,0);

aLinkedList.insertAt(9,1);

aLinkedList.insertAt(13,2);

aLinkedList.insertAt(8,1);

aLinkedList.insertAt(3,2);

System.out.println(aLinkedList);

System.out.println("Largo de lista: " + aLinkedList.length());

}

}

Answer 1

public class LinkedList {
    class Node {
        int value;
        Node nextNode;

        Node(int v, Node n)
        {
            value = v;
            nextNode = n;
        }

        Node (int v)
        {
            this(v,null);
        }
    }

    Node head; //head = null;

    LinkedList()
    {

    }

    int length()
    {
        Node tempPtr;
        int result = 0;
        tempPtr = head;

        while (tempPtr != null)
        {
            tempPtr = tempPtr.nextNode;
            result = result + 1;
        }

        return(result);
    }

    void insertAt(int v, int position)
    {
        Node newNode = new Node(v,null);
        Node tempPtr;

        int tempPosition = 0;

        if((head == null) || (position ==0))
        {
            newNode.nextNode = head;
            head = newNode;
        }

        else {
            tempPtr = head;

            while((tempPtr.nextNode != null)&&(tempPosition < position -1))
            {
                tempPtr = tempPtr.nextNode;
                tempPosition = tempPosition + 1;
            }

            if (tempPosition == (position - 1))
            {
                newNode.nextNode = tempPtr.nextNode;
                tempPtr.nextNode = newNode;
            }
        }
    }

    public void convertToRing(){
        if(head==null) return;
        Node tempPtr=head;

//Loop till tempPtr reaches to last node of Linked List
        while(tempPtr.nextNode != null){
            tempPtr = tempPtr.nextNode;
        }

//Now point last node to head instead of null
        tempPtr.nextNode=head;
    }

    public String toString()
    {
        Node tempPtr;
        tempPtr = head;
        String result = "";

        do
        {
            result = result + "[" + tempPtr.value + "| ]-->";
            tempPtr = tempPtr.nextNode;
        }while(tempPtr!= null && tempPtr!=head);

        if(tempPtr==null)
            result = result + "null";

        return result;
    }
}

public class LinkedListDemoInsDel {
    public static void main(String[] args)
    {

        LinkedList aLinkedList = new LinkedList();

        aLinkedList.insertAt(1,0);

        aLinkedList.insertAt(9,1);

        aLinkedList.insertAt(13,2);

        aLinkedList.insertAt(8,1);

        aLinkedList.insertAt(3,2);

        System.out.println(aLinkedList);

        System.out.println("Largo de lista: " + aLinkedList.length());
        aLinkedList.convertToRing();

        System.out.println(aLinkedList);
    }
}