public SkipList(List <T> inputList)
        {
            int maximumLevel = (int)Math.Log(inputList.Count, 2);

            Head = new SkipListNode <T> {
                Key = default(T), Level = maximumLevel
            };
            var a = Head.Next;

            for (int i = 0; i < inputList.Count; i++)
            {
                a = new SkipListNode <T> {
                    Key = inputList[i]
                };
                for (int j = 1; j <= maximumLevel; j++)
                {
                    if (i % Math.Pow(2, j) != 0)
                    {
                        a.Level = j - 1;
                    }
                }
                a = a.Next;
            }
            a = new SkipListNode <T> {
                Key = default(T), Level = maximumLevel, Next = null
            };
            var levelHead     = Head;
            var levelIterator = Head;

            a = levelHead.Lower;
            for (int i = 2; i <= maximumLevel; i++)
            {
                a = new SkipListNode <T> {
                    Key = default(T), Level = maximumLevel, Upper = a
                };
                while (levelIterator != null)
                {
                    if (levelIterator.Level >= i)
                    {
                        levelIterator.Lower = new SkipListNode <T> {
                            Key = levelIterator.Key, Level = levelIterator.Level, Upper = levelIterator
                        };
                        a.Next = levelIterator.Lower;
                        a      = a.Next;
                    }
                    levelIterator = levelIterator.Next;
                }
                a.Next = new SkipListNode <T> {
                    Key = default(T), Level = maximumLevel, Next = null, Upper = levelIterator
                };
                levelHead     = levelHead.Lower;
                a             = levelHead.Lower;
                levelIterator = levelHead;
            }
        }
        public void Add(T value)
        {
            var a       = Find(value);
            var newNode = new SkipListNode <T> {
                Key = value, Next = a.Next
            };

            a.Next = newNode;
            var randKey = new Random();
            int coin    = randKey.Next(2);

            while (coin != 0)
            {
                a       = a.Lower;
                newNode = new SkipListNode <T> {
                    Key = value, Next = a.Next
                };
                a.Next = newNode;
                coin   = randKey.Next(2);
            }
        }