/// <summary>
/// Inserts the given node underneath the given root according to the BinarySearchTree algorithm and then
/// rebalances the tree according to the red-black tree rules
/// </summary>
/// <param name="root">The root node of the tree</param>
/// <param name="node">The node to insert</param>
/// <returns>The new root of the tree as it may have changed</returns>
private (RedBlackNode <RbLineSegment> root, RbLineSegment higher, RbLineSegment lower) InsertBracketed(RedBlackNode <RbLineSegment> root, RedBlackNode <RbLineSegment> node)
{
RbLineSegment higher = null;
RbLineSegment lower = null;
if (root == null)
{
root = node;
++Count;
}
else
{
root.ResetHeight();
var compareResult = root.Value.CompareTo(node.Value);
if (compareResult > 0)
{
(root.Left, higher, lower) = InsertBracketed(root.Left, node);
if (higher == null && lower == null)
{
node.Value.NextHigher = higher = root.Value;
node.Value.NextLower = lower = root.Value.NextLower;
higher.NextLower = node.Value;
if (lower != null)
{
lower.NextHigher = node.Value;
}
}
}
else if (compareResult < 0)
{
(root.Right, higher, lower) = InsertBracketed(root.Right, node);
if (higher == null && lower == null)
{
node.Value.NextLower = lower = root.Value;
node.Value.NextHigher = higher = root.Value.NextHigher;
lower.NextHigher = node.Value;
if (higher != null)
{
higher.NextLower = node.Value;
}
}
}
else
{
throw new ArgumentException("Inserting duplicate in Red Black tree");
}
}
root = PostInsertCleanup(root, node);
return(root, higher, lower);
}
public void ResetHeight()
{
RedBlackNode <int> node = new RedBlackNode <int>(20);
Assert.AreEqual <int>(0, node.Height);
node.Left = new RedBlackNode <int>(10);
Assert.AreEqual <int>(0, node.Height);
node.ResetHeight();
Assert.AreEqual <int>(1, node.Height);
}
public void RotateRight_FullTree()
{
RedBlackNode <int> node = new RedBlackNode <int>(100);
node.Left = new RedBlackNode <int>(50);
node.Right = new RedBlackNode <int>(150);
node.Left.Left = new RedBlackNode <int>(25);
node.Left.Right = new RedBlackNode <int>(75);
node.Right.Left = new RedBlackNode <int>(125);
node.Right.Right = new RedBlackNode <int>(175);
node.ResetHeight();
node.Left.ResetHeight();
node.Right.ResetHeight();
node.Left.Left.ResetHeight();
node.Left.Right.ResetHeight();
node.Right.Left.ResetHeight();
node.Right.Right.ResetHeight();
node = node.RotateRight() as RedBlackNode <int>;
Assert.AreEqual <int>(50, node.Value);
Assert.AreEqual <int>(25, node.Left.Value);
Assert.AreEqual <int>(100, node.Right.Value);
Assert.AreEqual <int>(75, node.Right.Left.Value);
Assert.AreEqual <int>(150, node.Right.Right.Value);
Assert.AreEqual <int>(125, node.Right.Right.Left.Value);
Assert.AreEqual <int>(175, node.Right.Right.Right.Value);
Assert.AreEqual <int>(3, node.Height);
Assert.AreEqual <int>(0, node.Left.Height);
Assert.AreEqual <int>(2, node.Right.Height);
Assert.AreEqual <int>(1, node.Right.Right.Height);
Assert.AreEqual <int>(0, node.Right.Left.Height);
Assert.AreEqual <int>(0, node.Right.Right.Right.Height);
Assert.AreEqual <int>(0, node.Right.Right.Left.Height);
}
public void RotateRight_FullTree()
{
RedBlackNode<int> node = new RedBlackNode<int>(100);
node.Left = new RedBlackNode<int>(50);
node.Right = new RedBlackNode<int>(150);
node.Left.Left = new RedBlackNode<int>(25);
node.Left.Right = new RedBlackNode<int>(75);
node.Right.Left = new RedBlackNode<int>(125);
node.Right.Right = new RedBlackNode<int>(175);
node.ResetHeight();
node.Left.ResetHeight();
node.Right.ResetHeight();
node.Left.Left.ResetHeight();
node.Left.Right.ResetHeight();
node.Right.Left.ResetHeight();
node.Right.Right.ResetHeight();
node = node.RotateRight() as RedBlackNode<int>;
Assert.AreEqual<int>(50, node.Value);
Assert.AreEqual<int>(25, node.Left.Value);
Assert.AreEqual<int>(100, node.Right.Value);
Assert.AreEqual<int>(75, node.Right.Left.Value);
Assert.AreEqual<int>(150, node.Right.Right.Value);
Assert.AreEqual<int>(125, node.Right.Right.Left.Value);
Assert.AreEqual<int>(175, node.Right.Right.Right.Value);
Assert.AreEqual<int>(3, node.Height);
Assert.AreEqual<int>(0, node.Left.Height);
Assert.AreEqual<int>(2, node.Right.Height);
Assert.AreEqual<int>(1, node.Right.Right.Height);
Assert.AreEqual<int>(0, node.Right.Left.Height);
Assert.AreEqual<int>(0, node.Right.Right.Right.Height);
Assert.AreEqual<int>(0, node.Right.Right.Left.Height);
}
public void ResetHeight()
{
RedBlackNode<int> node = new RedBlackNode<int>(20);
Assert.AreEqual<int>(0, node.Height);
node.Left = new RedBlackNode<int>(10);
Assert.AreEqual<int>(0, node.Height);
node.ResetHeight();
Assert.AreEqual<int>(1, node.Height);
}
