public NodeLL Reorder(NodeLL start)
{
NodeLL current = start;
NodeLL dummy = new NodeLL(0);
Stack <NodeLL> s = new Stack <NodeLL>();
int length = GetLength(start);
int mid = length / 2;
for (int i = 0; i < mid; i++)
{
start = start.next;
}
for (int i = mid; i < length; i++)
{
s.Push(start);
start = start.next;
}
while (current != null)
{
dummy.next = current;
NodeLL stack = s.Pop();
current.next = stack;
current = current.next;
}
return(current);
}
public int GetLength(NodeLL start)
{
int count = 0;
while (start != null)
{
count++;
start = start.next;
}
return(count);
}
public void RemoveDuplicates(NodeLL start)
{
HashSet <int> map = new HashSet <int>();
NodeLL prev = null;
while (start != null)
{
if (map.Contains(start.data))
{
prev.next = start.next;
start = start.next;
}
else
{
map.Add(start.data);
prev = start;
start = start.next;
}
}
}