Check If Cycle exists in a Linked List

Check if the linked list contains a cycle

using System;
using System.Collections.Generic;
using System.Text;

namespace Algorithms
{
    public class LinkedList
    {
        private Node head;

        public LinkedList()
        {
            head = null;
        }

       
        public bool CheckCycle()
        {
            Node step1Node = head;
            Node step2Node = head.NextNode;
            
            while (true)
            {
                if ((step2Node == null)||(step2Node.NextNode == null))
                    return false;
                else if ((step1Node.Equals(step2Node))||(step1Node.Equals(step2Node.NextNode)))
                    return true;
                else
                { 
                step2Node = step2Node.NextNode;
                step2Node = step2Node.NextNode;
                step1Node = step1Node.NextNode;
                }
            }
        }
        public int FindPosition(int data)
        {
            Node checkNode = head;
            int position = 1;
            int dataPosition = 0;
            while (checkNode != null)
            {
                if (checkNode.DataValue == data)
                {
                    dataPosition = position;
                }
                checkNode = checkNode.NextNode;
                position = position + 1;
            }
            return dataPosition;

        }
    }
    public class Node
    {
        private int dataValue;
        private Node nextNode = null;

        public Node(int data)
        {
            dataValue = data;
        }
        public Node NextNode
        {
            get
            {
                return nextNode;
            }
            set
            {
                nextNode = value;
            }
        }
        public int DataValue
        {
            get
            {
                return dataValue;
            }
            set
            {
                dataValue = value;
            }
        }

    }
}

Nth Element from the last in a Linked List

Another advanced algorithm is to find the Nth Element from the LAST with the optimal performance.
Here is the implementation

using System;
using System.Collections.Generic;
using System.Text;

namespace Algorithms
{
    public class LinkedList
    {
        private Node head;

        public LinkedList()
        {
            head = null;
        }

        public int FindNthElementFromLast(int m)
        {
            int n = m - 1;
            int returnValue = -1;
            if (n >= 0)
            {
                Node nthElement = head;
                Node currentElement = head;
                for (int i =0;i less than n;i++)
                {
                    if (currentElement.NextNode != null)
                    {
                        currentElement = currentElement.NextNode;
                    }
                    else
                    {
                        returnValue = -1;
                        return returnValue;
                    }
                }

                if (returnValue != -1)
                {
                    while (currentElement.NextNode != null)
                    {
                        currentElement = currentElement.NextNode;
                        nthElement = nthElement.NextNode;
                    }
                    returnValue = nthElement.DataValue;
                }
            }
            return returnValue; 

        }
       
    }
    public class Node
    {
        private int dataValue;
        private Node nextNode = null;

        public Node(int data)
        {
            dataValue = data;
        }
        public Node NextNode
        {
            get
            {
                return nextNode;
            }
            set
            {
                nextNode = value;
            }
        }
        public int DataValue
        {
            get
            {
                return dataValue;
            }
            set
            {
                dataValue = value;
            }
        }

    }
}

Linked List SORT Algorithm

If you need a sort algorithm in Linked List. Please check other implementation in my last blog.

using System;
using System.Collections.Generic;
using System.Text;

namespace Algorithms
{
    public class LinkedList
    {
        private Node head;

        public LinkedList()
        {
            head = null;
        }

        public void Sort()
        {
            if (head != null)
            {
                int j = 0;
                Node MinElement = head;
                Node currentElement = MinElement.NextNode;
                while (currentElement != null)
                {
                   
                    if (currentElement.DataValue < MinElement.DataValue)
                    {
                        MinElement = currentElement;
                        Insert(MinElement.DataValue);
                        DeleteAtPosition(j+1);
                    }
                MinElement = MinElement.NextNode;
                }
            }
        }
       
    }
    public class Node
    {
        private int dataValue;
        private Node nextNode = null;

        public Node(int data)
        {
            dataValue = data;
        }
        public Node NextNode
        {
            get
            {
                return nextNode;
            }
            set
            {
                nextNode = value;
            }
        }
        public int DataValue
        {
            get
            {
                return dataValue;
            }
            set
            {
                dataValue = value;
            }
        }

    }
}