Answers for "linked list in c sharp"

linked list c#

using System;

namespace LinkedListPractice
{
    public class LinkedList
    {
        private class Node
        {
            public int value;
            public Node next;

            public Node(int value)
            {
                this.value = value;
            }
        }

        private Node Head;
        private Node Tail;
        private int size;

        public void AddLast(int item)
        {
            var node = new Node(item);

            if (IsEmpty())
                Head = Tail = node;
            else
            {
                Tail.next = node;
                Tail = node;
            }

            size++;
        }

        public void AddFirst(int item)
        {
            var node = new Node(item);

            if (IsEmpty())
                Head = Tail = node;
            else
            {
                node.next = Head;
                Head = node;
            }

            size++;
        }

        private bool IsEmpty()
        {
            return Head == null;
        }

        public int IndexOf(int item)
        {
            int index = 0;
            var current = Head;
            while (current != null)
            {
                if (current.value == item) return index;
                current = current.next;
                index++;
            }
            return -1;
        }

        public bool Contains(int item)
        {
            return IndexOf(item) != -1;
        }

        public void RemoveFirst()
        {
            if (IsEmpty())
                throw new InvalidOperationException();

            if (Head == Tail)
                Head = Tail = null;
            else
            {
                var second = Head.next;
                Head.next = null;
                Head = second;
            }

            size--;
        }

        public void RemoveLast()
        {
            if (IsEmpty())
                throw new InvalidOperationException();

            if (Head == Tail)
                Head = Tail = null;
            else
            {
                var previous = GetPrevious(Tail);
                Tail = previous;
                Tail.next = null;
            }

            size--;
        }

        private Node GetPrevious(Node node)
        {
            var current = Head;
            while (current != null)
            {
                if (current.next == node) return current;
                current = current.next;
            }
            return null;
        }

        public int Size()
        {
            return size;
        }

        public int[] ToArray()
        {
            int[] array = new int[size];
            var current = Head;
            var index = 0;
            while (current != null)
            {
                array[index++] = current.value;
                current = current.next;
            }

            return array;
        }

        public void Reverse()
        {
            if (IsEmpty()) return;

            var previous = Head;
            var current = Head.next;
            while (current != null)
            {
                var next = current.next;
                current.next = previous;
                previous = current;
                current = next;
            }

            Tail = Head;
            Tail.next = null;
            Head = previous;
        }

        public int GetKthFromTheEnd(int k)
        {
            if (IsEmpty())
                throw new InvalidOperationException();

            var a = Head;
            var b = Head;
            for (int i = 0; i < k - 1; i++)
            {
                b = b.next;
                if (b == null)
                    throw new InvalidOperationException();
            }
            while (b != Tail)
            {
                a = a.next;
                b = b.next;
            }
            return a.value;
        }

        public void PrintMiddle()
        {
            if (IsEmpty())
                throw new InvalidOperationException();

            var a = Head;
            var b = Head;
            while (b != Tail && b.next != Tail)
            {
                b = b.next.next;
                a = a.next;
            }

            if (b == Tail)
                Console.WriteLine(a.value);
            else
                Console.WriteLine(a.value + ", " + a.next.value);
        }

        public bool HasLoop()
        {
            var slow = Head;
            var fast = Head;

            while (fast != null && fast.next != null)
            {
                slow = slow.next;
                fast = fast.next.next;

                if (slow == fast)
                    return true;
            }

            return false;
        }

        
    }
}

create and return linked list c#

public class Node
    {
        public int data;
        public Node next;

        public Node(int data)
        {
            this.data = data;
        }
    }

	class Program
    {
        private static void Main(string[] args)
        {
            Node head = new Node(4);
            Node nodeB = new Node(2);
            Node nodeC = new Node(3);
            Node nodeD = new Node(10);

            head.next = nodeB;
            nodeB.next = nodeC;
            nodeC.next = nodeD;
            Console.WriteLine(countNodes(head));
        }

        static int countNodes(Node head)
        {
            int count = 1;
            Node current = head;

            while (current.next != null)
            {
                current = current.next;
                count += 1;
            }
            return count;
        }