library RemoveAlgo;

uses
  System.SysUtils,
  System.Classes;

type
   PNode = ^TNode;
   TNode = record
      Left: PNode;
      Right: PNode;
      Key: Byte;
   end;

{$R *.res}

function Minimum(Node: PNode): PNode;
begin
   if Node.Left = nil then
      Result := Node
   else
      Node := Minimum(Node.Left);
   Result := Node;
end;

function Remove(Node: PNode; Key: Byte): PNode;
begin
   if Node = nil then
      Remove := Node;
   if Key < Node.Key then
      Node.Left := Remove(Node.Left, Key)
   else
      if Key > Node.Key then
         Node.Right := Remove(Node.Right, Key)
      else
         if (Node.Left <> nil) and (Node.Right <> nil) then
         begin
            Node.Key := Minimum(Node.Right).Key;
            Dispose(Minimum(Node.Right));
            Node.Right := Remove(Node.Right, Node.Key);
         end
         else
            if Node.Left <> nil then
               Node := Node.Left
            else
               Node := Node.Right;
   Remove := Node;
end;

exports Remove;

begin
end.