internal T Index(int index)
{
if (index < 0 || index >= Length)
{
throw new IndexOutOfRangeException(nameof(index));
}
TreapNode current = this.Root;
int chunkBeginning = 0;
while (true)
{
int leftSubtreeSize = TreapNode.GetSize(current.LChild);
if (index < leftSubtreeSize)
{
current = current.LChild;
}
else
{
chunkBeginning += leftSubtreeSize;
index -= leftSubtreeSize;
if (index < current.Length)
{
return(current.Data[current.Offset + index]);
}
else
{
chunkBeginning += current.Length;
index -= current.Length;
current = current.RChild;
}
}
}
}
internal void Split(TreapNode node, int index, out TreapNode L, out TreapNode R)
{
TreapNode newTree = null;
int lBound = TreapNode.GetSize(node.LChild);
int rBound = lBound + node.Size;
if (index >= rBound) // going right
{
if (node.RChild == null)
{
R = null;
}
else
{
Split(node.RChild, index - rBound, out newTree, out R);
}
L = new TreapNode(node.Data, node.Offset, node.Length, node.Priority, node.LChild, newTree);
}
else if (index < lBound) // going left
{
if (node.LChild == null)
{
L = null;
}
else
{
Split(node.LChild, index, out L, out newTree);
}
R = new TreapNode(node.Data, node.Offset, node.Length, node.Priority, newTree, node.RChild);
}
else // split node in middle
{
index -= lBound;
L = new TreapNode(
data: node.Data,
offset: node.Offset,
length: index,
priority: RandomGenerator.Next(),
left: node.LChild,
right: null
);
R = new TreapNode(
data: node.Data,
offset: node.Offset + index,
length: node.Length - index,
priority: RandomGenerator.Next(),
left: null,
right: node.RChild
);
}
}
private void SplitStack(TreapNode node, int index, out TreapNode L, out TreapNode R)
{
Stack <TreapNode> path = new Stack <TreapNode>();
while (true)
{
path.Push(node);
int leftBound = TreapNode.GetSize(node.LChild);
int rightBound = leftBound + node.Size;
if (index < leftBound) // going left
{
node = node.LChild;
}
else if (rightBound <= index) // going right
{
node = node.RChild;
}
else // split node
{
L = new TreapNode(
data: node.Data,
offset: node.Offset,
length: index,
priority: RandomGenerator.Next(),
left: node.LChild,
right: null
);
R = new TreapNode(
data: node.Data,
offset: node.Offset + index,
length: node.Length - index,
priority: RandomGenerator.Next(),
left: null,
right: node.RChild
);
break;
}
}
Console.Error.WriteLine(string.Join("\n", path.Reverse()));
while (path.Count > 0)
{
var currentNode = path.Pop();
}
}