private RedBlackNode <T> add(RedBlackNode <T> current, T value)
{
if (current == null)
{
return(new RedBlackNode <T>(value));
}
//if a 4-node is found, split it
if (current.Left?.Red == true && current.Right?.Red == true)
{
FlipColor(current);
}
//if the current's value is greater than that of the Tvalue, Tvalue will continue along Left
if (current.Value.CompareTo(value) >= 0)
{
current.Left = add(current.Left, value);
}
//if the current's value is less than that of the Tvalue, Tvalue will continue along Right
else
{
current.Right = add(current.Right, value);
}
//rotate left to make the 3-node left leaning
if (isBlack(current.Left) && current.Right?.Red == true)
{
current = RotateLeft(current);
}
//rotate right to correct the unbalanced 4-node
if (current.Left?.Red == true && current.Left?.Left?.Red == true)
{
current = RotateRight(current);
}
return(current);
}
private RedBlackNode <T> remove(RedBlackNode <T> current, T value)
{
if (Root == null)
{
return(null);
}
else
{
//searching left
if (current.Value.CompareTo(value) > 0)
{
if (current.Left != null)
{
if (isBlack(current.Left) == true && isBlack(current.Left.Left) == true)
{
current = MoveRedLeft(current);
}
current.Left = remove(current.Left, value);
}
}
//searching right/value found
else
{
if (isBlack(current.Left) == false)
{
current = RotateRight(current);
}
if (current.Value.CompareTo(value) == 0 && current.Left == null && current.Right == null)
{
return(null);
}
if (isBlack(current.Right) == true && isBlack(current.Right?.Left) == true)
{
current = MoveRedRight(current);
}
if (current.Value.CompareTo(value) == 0)
{
RedBlackNode <T> temp = current.Right;
while (temp.Left != null)
{
temp = temp.Left;
}
current.Value = temp.Value;
current.Right = remove(current.Right, temp.Value);
}
else if (current?.Right != null)
{
current.Right = remove(current.Right, value);
}
}
}
return(FixUp(current));
}
public void Add(T value)
{
Root = add(Root, value);
Root.Red = false;
}
public void Remove(T value)
{
Root = remove(Root, value);
Root.Red = false;
}