public bool Remove(T item)
{
ModuleProc PROC = new ModuleProc(this.DYN_MODULE_NAME, "Remove");
bool result = default(bool);
try
{
SearchResult r = this.Search(item);
if (r.Node == null)
{
// key not found
return(false);
}
RbtreeNode x = r.Node;
RbtreeNode z = null;
RbtreeNode y = x;
RbtreeColor y_color = y.Color;
// left is null
if (x.Left == null)
{
z = x.Right;
this.Transplant(x, z);
}
else if (x.Right == null)
{
z = x.Left;
this.Transplant(x, z);
}
else
{
y = x.Right.Minimum;
y_color = y.Color;
z = y.Right;
if (y.Parent != x)
{
this.Transplant(y, y.Right);
y.Right = x.Right;
y.Right.Parent = y;
}
else
{
z.Parent = y;
}
this.Transplant(x, y);
y.Left = x.Left;
y.Left.Parent = y;
y.Color = x.Color;
}
if (y_color == Rbtree <T> .RbtreeColor.Black)
{
//fix up
x = z;
while (x != null &&
x != _rootNode &&
x.IsBlack)
{
if (x.p.Left == x)
{
RbtreeNode w = x.p.Right;
if (w.IsRed)
{
w.SetColorBlack();
x.p.SetColorRed();
this.RotateLeft(x.p);
w = x.p.Right;
}
if (w.Left != null && w.Right != null)
{
if (w.Left.IsBlack && w.Right.IsBlack)
{
w.SetColorRed();
x = x.p;
}
else if (w.Right.IsBlack)
{
w.Left.SetColorBlack();
w.SetColorRed();
this.RotateRight(w);
w = x.p.Right;
}
w.Color = w.p.Color;
x.p.SetColorBlack();
w.Right.SetColorBlack();
this.RotateLeft(x.p);
x = _rootNode;
}
}
else
{
RbtreeNode w = x.p.Left;
if (w.IsRed)
{
w.SetColorBlack();
x.p.SetColorRed();
this.RotateRight(x.p);
w = x.p.Left;
}
if (w.Left != null && w.Right != null)
{
if (w.Left.IsBlack && w.Right.IsBlack)
{
w.SetColorRed();
x = x.p;
}
else if (w.Left.IsBlack)
{
w.Right.SetColorBlack();
w.SetColorRed();
this.RotateLeft(w);
w = x.p.Left;
}
w.Color = w.p.Color;
x.p.SetColorBlack();
w.Left.SetColorBlack();
this.RotateRight(x.p);
x = _rootNode;
}
}
}
if (x != null)
{
x.SetColorBlack();
}
}
_count--;
}
catch (Exception ex)
{
Log.Exception(PROC, ex);
}
return(result);
}
public void Add(T item)
{
ModuleProc PROC = new ModuleProc(this.DYN_MODULE_NAME, "Add");
try
{
SearchResult lookup = this.Search(item);
if (lookup.Node != null)
{
return;
}
// new node
lookup.Node = new Rbtree <T> .RbtreeNode()
{
Color = Rbtree <T> .RbtreeColor.Red,
Left = null,
Right = null,
Value = item,
Parent = lookup.ParentNode
};
RbtreeNode x = lookup.Node;
RbtreeNode p = lookup.ParentNode;
bool isLeft = lookup.IsLeft;
_count++;
if (p != null)
{
if (isLeft)
{
if (p == _minNode)
{
_minNode = x;
}
}
else
{
if (p == _maxNode)
{
_maxNode = x;
}
}
p[isLeft] = x;
}
else
{
_minNode = x;
_maxNode = x;
_rootNode = x;
}
// rotations
while (((p = x.Parent) != null) &&
p.IsRed)
{
RbtreeNode g = p.Parent;
// if parent is at left of grandpa
if (p == g.Left)
{
RbtreeNode u = g.Right;
// if uncle is red
if ((u != null) && (u.IsRed))
{
p.SetColorBlack();
u.SetColorBlack();
g.SetColorRed();
x = g;
}
else
{
if (x == p.Right)
{
this.RotateLeft(p);
x = p;
p = x.Parent;
}
p.SetColorBlack();
g.SetColorRed();
this.RotateRight(g);
}
}
else // right of parent
{
RbtreeNode u = g.Left;
// if uncle is red
if ((u != null) && (u.IsRed))
{
p.SetColorBlack();
u.SetColorBlack();
g.SetColorRed();
x = g;
}
else
{
if (x == p.Left)
{
this.RotateRight(p);
x = p;
p = x.Parent;
}
p.SetColorBlack();
g.SetColorRed();
this.RotateLeft(g);
}
}
}
// root always black
_rootNode.Color = Rbtree <T> .RbtreeColor.Black;
}
catch (Exception ex)
{
Log.Exception(PROC, ex);
}
}
