delphi - 连接4 : Check for winner

Question

在 Delphi 中，我有一个数组形式的 Connect 4 板表示(7 列 x 6 行):

TBoard = Array[1..7, 1..6] of SmallInt;
Board: TBoard; // instance ob TBoard

每个元素可以有三种不同的状态:

• 1 = 玩家 1 的棋子
• 0 = 空
• -1 = 玩家 2 的棋子

现在我需要一个函数来检查是否有获胜者或平局:

function CheckForWinner(): SmallInt;

...其中 1 表示玩家 1 获胜，0 表示平局，-1 表示玩家 2 获胜，“nil”表示游戏尚未结束。

我的草稿如下 - 分为两个单一功能:

function CheckForWinner(): SmallInt;
var playerToCheck: ShortInt;
    s, z: Byte;
    draw: Boolean;
begin
  draw := TRUE;
  for s := 1 to 7 do begin
    for z := 1 to 6 do begin
      if Board[s, z] = 0 then draw := FALSE; // if there are empty fields then it is no draw
    end;
  end;
  if draw then begin
    result := 0;
  end
  else begin
    playerToCheck := Board[lastPieceX, lastPieceY]; // only for last-moving player
    if searchRow(playerToCheck, +1, 0, lastPieceX, lastPieceY) then // search right/left
      result := playerToCheck
    else if searchRow(playerToCheck, 0, +1, lastPieceX, lastPieceY) then // search up/down
      result := playerToCheck
    else if searchRow(playerToCheck, +1, +1, lastPieceX, lastPieceY) then // search right-down/left-up
      result := playerToCheck
    else if searchRow(playerToCheck, +1, -1, lastPieceX, lastPieceY) then // search right-up/left-down
      result := playerToCheck;
    else
      result := nil;
    end;
  end;
end;

function searchRow(player: SmallInt; sChange, zChange: ShortInt; startS, startZ: Byte): Boolean;
var inRow, s, z: SmallInt;
begin
  inRow := 0;
  s := startS;
  z := startZ;
  while (Board[s, z] = player) AND (inRow < 4) AND (s >= 1) AND (s <= 7) AND (z >= 1) AND (z <= 6) do begin
    s := s+sChange;
    z := z+zChange;
    inRow := inRow+1;
  end;
  s := startS-sChange;
  z := startZ-zChange;
  while (Board[s, z] = player) AND (inRow < 4) AND (s >= 1) AND (s <= 7) AND (z >= 1) AND (z <= 6) do begin
    s := s-sChange;
    z := z-zChange;
    inRow := inRow+1;
  end;
  if inRow = 4 then
    result := TRUE
  else
    result := FALSE;
end;

您对这种方法有何看法？您有更好(更快/更短)的解决方案吗？

非常感谢!

Answer 1

我没有读过你的代码。我只是选择自己用白纸写一些内容。

这是我的版本:

const
  RowCount = 6;
  ColCount = 7;

type
  TState = (stNone, stA, stB);
  TBoard = array [1..RowCount] of array [1..ColCount] of TState;

function ValidLocation(Row, Col: Integer): Boolean;
begin
  Result := InRange(Row, 1, RowCount) and InRange(Col, 1, ColCount);
end;

procedure Check(
  const Board: TBoard;
  const StartRow, StartCol: Integer;
  const RowDelta, ColDelta: Integer;
  out Winner: TState
);
var
  Row, Col, Count: Integer;
  State: TState;
begin
  Winner := stNone;
  Row := StartRow;
  Col := StartCol;
  State := Board[Row, Col];
  if State=stNone then
    exit;
  Count := 0;
  while ValidLocation(Row, Col) and (Board[Row, Col]=State) do begin
    inc(Count);
    if Count=4 then begin
      Winner := State;
      exit;
    end;
    inc(Row, RowDelta);
    inc(Col, ColDelta);
  end;
end;

function Winner(const Board: TBoard): TState;
var
  Row, Col: Integer;
begin
  for Row := 1 to RowCount do begin
    for Col := 1 to ColCount do begin
      Check(Board, Row, Col, 0, 1, Result);//check row
      if Result<>stNone then
        exit;
      Check(Board, Row, Col, 1, 0, Result);//check column
      if Result<>stNone then 
        exit;
      Check(Board, Row, Col, 1, 1, Result);//check diagonal
      if Result<>stNone then 
        exit;
      Check(Board, Row, Col, 1, -1, Result);//check other diagonal
      if Result<>stNone then 
        exit;
    end;
  end;
  Result := stNone;
end;

一大堆代码。使用暴力方法，对于 Connect 4 来说性能并不重要。不喜欢四个相同的 if Result<>stNone then exit;行，但你肯定可以想出一种更简洁的方法。代码尚未运行。可能根本就行不通!!这正是我的大脑试图解决问题的方式。