unit BinTree;

interface

uses System.SysUtils, System.Types, Generics.Collections;

type
   TNodeCoords = TList<TPoint>;

type
   TComparator<TKey> = function(const A, B: TKey): ShortInt;
   // negatiive: A < B; zero: A = B; positive: A > B

   TBinaryTree<K, V> = class
   private type
      PNode = ^TNode;

      TNode = record
         Value: V;
         Key: K;
         PLeft, PRight: PNode;

         constructor Create(const Key: K; const Value: V);
      end;

   function GetPreviousNode(const Key: K): PNode;
   function GetPreReplaceNode(startNode: PNode): PNode;
   function GetNodeCoords(Node: PNode): TNodeCoords;

   var
      FCount: Integer;
      Comparator: TComparator<K>;
      PHead: PNode;
   public
      constructor Create(Comparator: TComparator<K>);
      property Count: Integer read FCount;
      procedure Add(const Key: K; const Value: V);
      procedure Delete(const Key: K);

   end;

implementation