SinglyLinkedList.cs

SinglyLinkedList.cs

//*********************************************************
//
// Copyright (c) yinyue200.com. All rights reserved.
// This code is licensed under the MIT License (MIT).
// THIS CODE IS PROVIDED *AS IS* WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY
// IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
// PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.
//
//*********************************************************
    class SinglyLinkedList<T>:ICollection<T>,IReadOnlyCollection<T>
    {
        SingleLinkedNode<T> Head;
        SingleLinkedNode<T> Tail;

        public int Count { get; private set; } = 0;

        public bool IsReadOnly => false;

        public void Add(T item)
        {
            if (Head == null)
            {
                Head = new SingleLinkedNode<T>(item);
                Tail = Head;
                Count = 1;
            }
            else
            {
                var node = new SingleLinkedNode<T>(item);
                Tail.Next = node;
                Tail = node;
                Count++;
            }
        }

        public void Clear()
        {
            Tail = null;
            Head = null;
            Count = 0;
        }

        public bool Contains(T item) => System.Linq.Enumerable.Contains(this, item);

        public void CopyTo(T[] array, int arrayIndex)
        {
            SingleLinkedNode<T> node = Head;
            for (var i = arrayIndex; i < array.Length; i++)
            {
                array[i] = node.Value;
                node = node.Next;
            }
        }

        public IEnumerator<T> GetEnumerator()
        {
            SingleLinkedNode<T> node = Head;
            while (true)
            {
                if (node == null)
                    break;
                yield return node.Value;
                node = node.Next;
            }
        }

        public bool Remove(T item)
        {
            int rmcount = 0;
            SingleLinkedNode<T> lnode = null;
            SingleLinkedNode<T> node = Head;
            while (true)
            {
                if (node == null)
                    break;
                if (EqualityComparer<T>.Default.Equals(item, node.Value))
                {
                    if (lnode == null)
                    {
                        Head = node.Next;
                    }
                    else
                    {
                        lnode.Next = node.Next;
                    }
                    if(node.Next==null)
                    {
                        Tail = lnode;
                    }
                    rmcount++;
                }
                lnode = node;
                node = node.Next;
            }
            Count -= rmcount;
            return rmcount > 0;
        }

        IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();

        private sealed class SingleLinkedNode<TValue>
        {
            public SingleLinkedNode(TValue NewValue)
            {
                Value = NewValue;
            }
            public SingleLinkedNode<TValue> Next;
            public TValue Value;
        }

    }