private void DeletionCase1(Tree tree)
{
Tree sibiling = tree.Sibling();
Tree parent = tree.Parent;
if (sibiling != null)
{
if (sibiling.Color == NodeColor.Black)
{
if (sibiling.Left != null && sibiling.Left.Color == NodeColor.Red)
{
if (sibiling == parent.Left)
{
sibiling.Left.Color = NodeColor.Black;
RightRotate(parent);
}
else if (sibiling == parent.Right)
{
sibiling.Left.Color = NodeColor.Black;
RightRotate(sibiling);
LeftRotate(parent);
}
else
{
Console.WriteLine("10.40 Unexpected block");
}
}
else if (sibiling.Right != null && sibiling.Right.Color == NodeColor.Red)
{
if (sibiling == parent.Left)
{
sibiling.Right.Color = NodeColor.Black;
LeftRotate(sibiling);
RightRotate(parent);
}
else if (sibiling == parent.Right)
{
sibiling.Right.Color = NodeColor.Black;
LeftRotate(parent);
}
else
{
Console.WriteLine("10.50 Unexpected block");
}
}
else
{
sibiling.Color = NodeColor.Red;
if (parent.Color == NodeColor.Red)
{
parent.Color = NodeColor.Black;
}
else
{
DeletionCase1(parent);
}
}
}
else
{
//sibiling is red,so parent must be black
if (sibiling == parent.Left)
{
sibiling.Color = NodeColor.Black;
if (parent == Root)
{
Console.WriteLine("10.60 Unexpected block");
}
parent.Color = NodeColor.Red;
RightRotate(parent);
}
else if (sibiling == parent.Right)
{
sibiling.Color = NodeColor.Black;
if (parent == Root)
{
Console.WriteLine("10.70 Unexpected block");
}
parent.Color = NodeColor.Red;
LeftRotate(parent);
}
else
{
Console.WriteLine("10.80 Unexpected block");
}
}
}
else
{
if (tree == Root)
{
tree.Color = NodeColor.Black;
}
else
{
Console.WriteLine("10.30 Unexpected block");
}
}
}
