internal void IncrementHeight()
{
var newForwards = new SkipListNode <T> [Height + 1];
for (int i = 0; i < Height; i++)
{
newForwards[i] = forwards[i];
}
forwards = newForwards;
}
public bool Remove(T value)
{
if (Count == 0)
{
return(false);
}
var nodesForUpdate = new SkipListNode <T> [Height];
var curNode = Head;
for (int i = Height - 1; i >= 0; i--)
{
while (curNode[i] != null && value.CompareTo(curNode[i].Value) > 0)
{
curNode = curNode[i];
}
nodesForUpdate[i] = curNode;
}
var nodeToDelete = nodesForUpdate[0][0];
if (nodeToDelete != null && value.CompareTo(nodeToDelete.Value) == 0)
{
for (int i = 0; i < Head.Height; i++)
{
if (nodesForUpdate[i][i] != nodeToDelete)
{
break;
}
else
{
nodesForUpdate[i][i] = nodeToDelete[i];
}
}
nodeToDelete.Invalidate();
if (Head[Head.Height - 1] == null)
{
Head.DecrementHeight();
}
Count--;
return(true);
}
else
{
return(false);
}
}
public void Add(T value)
{
var nodesForUpdate = new SkipListNode <T> [Height];
var curNode = Head;
for (int i = Height - 1; i >= 0; i--)
{
while (curNode[i] != null && value.CompareTo(curNode[i].Value) > 0)
{
curNode = curNode[i];
}
nodesForUpdate[i] = curNode;
}
var nodeBeforeNodeForInsertion = nodesForUpdate[0];
if (nodeBeforeNodeForInsertion[0] != null && value.CompareTo(nodeBeforeNodeForInsertion[0].Value) == 0)
{
throw new ArgumentException("Tried to insert duplicate value!");
}
int height = 1;
while (randomizer.NextDouble() < probability && height < Head.Height + 1)
{
height++;
}
var newNode = new SkipListNode <T>(value, height);
if (height > Head.Height)
{
Head.IncrementHeight();
Head[Head.Height - 1] = newNode;
}
for (int i = 0; i < newNode.Height; i++)
{
if (i < nodesForUpdate.Length)
{
newNode[i] = nodesForUpdate[i][i];
nodesForUpdate[i][i] = newNode;
}
}
Count++;
}
internal void DecrementHeight()
{
if (Height == 1)
{
return;
}
var newForwards = new SkipListNode <T> [Height - 1];
for (int i = 0; i < Height - 1; i++)
{
newForwards[i] = forwards[i];
}
forwards = newForwards;
}
public void Clear()
{
var curNode = Head;
var lastNode = Head;
while (curNode != null)
{
curNode = curNode[0];
lastNode.Invalidate();
lastNode = curNode;
}
Head = new SkipListNode <T>(default(T), 1);
Count = 0;
randomizer = new Random();
}
public SkipList()
{
Head = new SkipListNode <T>(default(T), 1);
Count = 0;
randomizer = new Random();
}