CircularLinkedList.cs

usingSystem;

namespaceDataStructures.LinkedList.CircularLinkedList
{
/// <summary>
/// CircularLinkedList.
/// @author Mohit Singh. <a href="https://github.com/mohit-gogitter">mohit-gogitter</a>
/// </summary>
/// <typeparam name="T">The generic type parameter.</typeparam>
publicclassCircularLinkedList<T>
{
/// <summary>
/// Points to the last node in the Circular Linked List.
/// </summary>
privateCircularLinkedListNode<T>?tail;

/// <summary>
/// Initializes a new instance of the <see cref="CircularLinkedList{T}"/> class.
/// </summary>
publicCircularLinkedList()
{
tail=null;
}

/// <summary>
/// Gets the head node (tail.Next) of the Circular Linked List.
/// </summary>
publicCircularLinkedListNode<T>?GetHead()
{
returntail?.Next;
}

/// <summary>
/// Determines whether the Circular Linked List is empty.
/// </summary>
/// <returns>True if the list is empty; otherwise, false.</returns>
publicboolIsEmpty()
{
returntail==null;
}

/// <summary>
/// Inserts a new node at the beginning of the Circular Linked List.
/// </summary>
/// <param name="data">The data to insert into the new node.</param>
publicvoidInsertAtBeginning(Tdata)
{
varnewNode=newCircularLinkedListNode<T>(data);
if(IsEmpty())
{
tail=newNode;
tail.Next=tail;
}
else
{
newNode.Next=tail!.Next;
tail.Next=newNode;
}
}

/// <summary>
/// Inserts a new node at the end of the Circular Linked List.
/// </summary>
/// <param name="data">The data to insert into the new node.</param>
publicvoidInsertAtEnd(Tdata)
{
varnewNode=newCircularLinkedListNode<T>(data);
if(IsEmpty())
{
tail=newNode;
tail.Next=tail;
}
else
{
newNode.Next=tail!.Next;
tail.Next=newNode;
tail=newNode;
}
}

/// <summary>
/// Inserts a new node after a specific value in the list.
/// </summary>
/// <param name="value">The value to insert the node after.</param>
/// <param name="data">The data to insert into the new node.</param>
publicvoidInsertAfter(Tvalue,Tdata)
{
if(IsEmpty())
{
thrownewInvalidOperationException("List is empty.");
}

varcurrent=tail!.Next;
do
{
if(current!.Data!.Equals(value))
{
varnewNode=newCircularLinkedListNode<T>(data);
newNode.Next=current.Next;
current.Next=newNode;

return;
}

current=current.Next;
}
while(current!=tail.Next);
}

/// <summary>
/// Deletes a node with a specific value from the list.
/// </summary>
/// <param name="value">The value of the node to delete.</param>
publicvoidDeleteNode(Tvalue)
{
if(IsEmpty())
{
thrownewInvalidOperationException("List is empty.");
}

varcurrent=tail!.Next;
varprevious=tail;

do
{
if(current!.Data!.Equals(value))
{
if(current==tail&&current.Next==tail)
{
tail=null;
}
elseif(current==tail)
{
previous!.Next=tail.Next;
tail=previous;
}
elseif(current==tail.Next)
{
tail.Next=current.Next;
}
else
{
previous!.Next=current.Next;
}

return;
}

previous=current;
current=current.Next;
}
while(current!=tail!.Next);
}
}
}