public Node IterativeKLastElement(Node head, int k)
{
if (head == null || k < 0) return null;
if (head !=null && k == 0) return head;
int count = 0;
Node p = head;
while(p!=null && count <k-1)
{
count++;
p = p.Next;
}
if(p==null)
{
return null;
}
Node p1 = head;
while(p.Next !=null)
{
p = p.Next;
p1 = p1.Next;
}
return p1;
}
public void InsertAtBeginning(ref Node head, int key)
{
Node n = new Node(key);
if(head == null)
{
head = n;
}
else
{
n.Next = head;
head = n;
}
}
public void InsertSort(Node head)
{
Node p = head;
Node temp = null;
Node result = null;
while (p != null)
{
temp = p.Next;
SortedInsert(ref result, p);
p = temp;
}
head = result;
}
public Node MergeLists(Node head1, Node head2)
{
Node result = null;
if(head1 == null)
{
return head2;
}
else if( head2 == null)
{
return head1;
}
else
{
Node p1 = head1;
Node p2 = head2;
if(p1.Key<=p2.Key)
{
result = p1;
result.Next = MergeLists(p1.Next, p2);
}
else
{
result = p2;
result.Next = MergeLists(p1, p2.Next);
}
}
return result;
}
private void SortedInsert(ref Node head, Node p)
{
if(head == null || head.Key == p.Key)
{
p.Next = head;
head = p;
return;
}
else
{
Node t = head;
while(t.Next!=null && t.Next.Key < p.Key)
{
t = t.Next;
}
p.Next = t.Next;
t.Next = p;
}
}
public void SortedInsert(ref Node head, int k)
{
Node n = new Node(k);
SortedInsert(ref head, n);
}
public void RecursiveReverse(ref Node head)
{
if (head == null || head.Next == null) return;
Node p = head;
Node temp = p.Next;
RecursiveReverse(ref temp);
p.Next.Next = p;
p.Next = null;
head = temp;
}
public Node RecursiveKLastElement(Node head, ref int count, int K)
{
if(head == null)
{
return null;
}
//Call stops with the last node and only then the count gets incremented for the first time.
Node res = RecursiveKLastElement(head.Next, ref count, K);
count++;
if(count ==K)
{
return head;
}
else
{
return res;
}
}
public void Print(Node head)
{
if(head ==null) return;
Node p = head;
while(p!=null)
{
Console.WriteLine(p.Key);
p = p.Next;
}
}
