DataStructuresCSharp/C#/Datastructures/LinkedList/LinkedList.cs

175 lines
5.0 KiB
C#

namespace C_.Datastructures.LinkedList
{
public class LinkedList<T>
{
internal LinkedListNode<T>? Head { get; set; } = default;
private int Count { get; set; } = 0;
public static LinkedList<T> Create()
{
//Create a new empty list
return new LinkedList<T>();
}
public static LinkedList<T> Create(T? value)
{
//Create a new Class with a single item
return new LinkedList<T>()
{
Head = LinkedListNode<T>.Create(value, null),
Count = 1
};
}
public static LinkedList<T> Create(LinkedList<T> list1, LinkedList<T> list2)
{
//Append a previous list to a new List
LinkedList<T> list;
list = list1;
if (list == null || list.Count == 0) return list2;
//Find end of list and append fist item of next list
if (list2 == null || list.Count == 0) return list;
LinkedListNode<T>? end = list.Traverse();
end!.Next = list2!.Head;
list.Count += list2!.Count;
return list;
}
public T? this[int i]
{
get
{
//Check Range
if (i >= Count || i < 0) throw new System.Exception("Error! Index out of Bounds");
//Return Value
LinkedListNode<T>? node = Traverse(i);
if (node != null) return node.Value;
return default;
}
set
{
//Check Range
if (i >= Count || i < 0) throw new System.Exception("Error! Index out of Bounds");
//Change Value
LinkedListNode<T>? node = Traverse(i);
node!.Value = value;
}
}
public void Append(T? value)
{
//Create new node
Count++;
LinkedListNode<T> newItem = LinkedListNode<T>.Create(value, default);
//Set head to new item if list is empty
if (Head == null)
{
Head = newItem;
return;
}
//Find last item in list
LinkedListNode<T>? end = Head;
if (end != null)
{
end = Traverse();
}
//Append item to end
end!.Next = newItem;
}
public void Insert(int index, T? value)
{
Count++;
if (index > Count || index < 0) throw new System.Exception("Error! Index outside of Bounds");
//Set head to new item if list is empty
if (index == 0 || Head == null)
{
Head = LinkedListNode<T>.Create(value, Head);
return;
}
//Fetch point in list at which item will be added
LinkedListNode<T>? node = Traverse(index - 1);
node!.Next = LinkedListNode<T>.Create(value, node!.Next);
}
public void Delete(int index)
{
Count--;
if (index > Count || index < 0) throw new System.Exception("Error! Index outside of Bounds");
//Check if we are trying to reference the first item
if (index == 0 && Head != default)
{
Head = Head!.Next;
return;
}
//Find node before the one we are trying to delete and then remove / relink
LinkedListNode<T>? node = Traverse(index - 1);
node!.Next = node.Next!.Next;
}
public int GetCount()
{//Return the number of items in the list
return Count;
}
private LinkedListNode<T>? Traverse()
{
//Start at Head of list
LinkedListNode<T>? node = Head;
if (node != null)
{
//continue to end of list
while (node!.Next != default)
{
node = (LinkedListNode<T>)node.Next;
}
}
return node;
}
//private static LinkedListNode<T>? Traverse(LinkedListNode<T> start){
// //Start at given point in list
// LinkedListNode<T>? node = start;
// if (node != null)
// {
// //Continue to end of list
// while (node!.Next != default)
// {
// node = (LinkedListNode<T>)node.Next;
// }
// }
// return node;
//}
private LinkedListNode<T>? Traverse(int i)
{
//Start at given point in list
LinkedListNode<T>? node = Head;
if (node != null || i == 0)
{
//Continue to end of list
for (int j = 0; j < i; j++)
{
if (node!.Next == null) return null;
node = (LinkedListNode<T>)node.Next;
}
}
return node;
}
}
}