//O(log(n)
public void Insert(T value)
{
//find the random level up to which we link the new node
var level = 0;
for (int i = 0; i < MaxHeight
&& coinFlipper.Next(0, 2) == 1; i++)
{
level++;
}
var newNode = new SkipListNode<T>()
{
value = value,
//only level + 1 number of links (level is zero index based)
Next = new SkipListNode<T>[level + 1]
};
//init current to head before insertion
var current = Head;
//go down from top level
for (int i = MaxHeight - 1; i >= 0; i--)
{
//move on current level of linked list
//until next element is less than new value to insert
while (true)
{
if (current.Next[i] == null
|| current.Next[i].value.CompareTo(value) > 0)
{
break;
}
current = current.Next[i];
}
//if this level is greater than
//maximum levels of link for new node
//then jump to next level
if (i > level)
{
continue;
}
//insert and update pointers
newNode.Next[i] = current.Next[i];
current.Next[i] = newNode;
//for base level set previous node
if (i == 0)
{
newNode.Prev = current;
}
}
}
public SkipList(int maxHeight = 32)
{
MaxHeight = maxHeight;
Head = new SkipListNode<T>()
{
Prev = null,
Next = new SkipListNode<T>[maxHeight],
value = default(T)
};
}
public bool MoveNext()
{
if (current.Next[0] != null)
{
current = current.Next[0];
return(true);
}
return(false);
}
public void Dispose()
{
head = null;
current = null;
}
public void Reset()
{
current = head;
}
internal SkipListEnumerator(SkipListNode <T> head)
{
this.head = head;
this.current = head;
}
