/// <summary>
/// return a node which overlaps item
/// returns a pointer to an element x in the interval tree T such that x:int overlaps interval i , or a pointer to the sentinel T:nil if no such element
/// </summary>
/// <param name="item"></param>
/// <returns></returns>
public IntervalTreeNode Search(Interval item)
{
IntervalTreeNode x = root;
while (x != null && !x.Interval.Overlap(item))
{
if (x.Left != null && x.Left.Max >= item.Low)
{
x = x.Left;
}
else
{
x = x.Right;
}
}
return(x);
}
/// <summary>
/// Red Black insert. adds the element x, who has interval attribute.
/// </summary>
/// <param name="key"></param>
/// <param name="val"></param>
public void Insert(Interval item)
{
Debug.Assert(item != null);
IntervalTreeNode node = null, inserted = new IntervalTreeNode(item);
count++;
IntervalTreeNode x = root;
while (x != null)
{
node = x;
x = item.Low.CompareTo(node.Interval.Low) < 0 ? x.Left : x.Right;
}
inserted.Parent = node;
//first insert a node
if (node == null)
{
root = inserted;
}
else if (inserted.Interval.Low < node.Interval.Low)
{
node.Left = inserted;
}
else
{
node.Right = inserted;
}
inserted.Left = inserted.Right = null;
inserted.Color = Color.RED;
//fix up the insert node, so red black tree reserve
InsertFixup(inserted);
}