实施和使用四行（connect4）游戏的MinMax
我试图为连续四次（或连接四次或连接四次）游戏实现MinMax算法。
我认为我有这个想法，它应该建立一个可能的板到一定深度的树，评估它们并返回它们的分数，然后我们就取得这些分数的最大值。
因此， aiChooseCol()通过调用MinMax() aiChooseCol()检查每个可能列的得分，并返回最大得分的列。
现在我不确定，这是调用MinMax()的正确方法吗？
检查temp = Math.Max(temp, 1000);是否正确temp = Math.Max(temp, 1000); ？
我仍然没有启动启发式功能，但这应该至少可以识别出一个胜出的列并选择它，但是目前它只是从左侧选择第一个空列...我无法弄清楚我做错了什么。
private int AiChooseCol()
{
int best = -1000;
int col=0;
for (int i = 0; i < m_Board.Cols; i++)
{
if (m_Board.CheckIfColHasRoom(i))
{
m_Board.FillSignInBoardAccordingToCol(i, m_Sign);
int t = MinMax(5, m_Board, board.GetOtherPlayerSign(m_Sign));
if (t > best)
{
best = t;
col = i;
}
m_Board.RemoveTopCoinFromCol(i);
}
}
return col;
}
private int MinMax(int Depth, board Board, char PlayerSign)
{
int temp=0;
if (Depth <= 0)
{
// return from heurisitic function
return temp;
}
char otherPlayerSign = board.GetOtherPlayerSign(PlayerSign);
char checkBoard = Board.CheckBoardForWin();
if (checkBoard == PlayerSign)
{
return 1000;
}
else if (checkBoard == otherPlayerSign)
{
return -1000;
}
else if (!Board.CheckIfBoardIsNotFull())
{
return 0; // tie
}
if (PlayerSign == m_Sign) // maximizing Player is myself
{
temp = -1000;
for (int i = 0; i < Board.Cols; i++)
{
if (Board.FillSignInBoardAccordingToCol(i, PlayerSign)) // so we don't open another branch in a full column
{
var v = MinMax(Depth - 1, Board, otherPlayerSign);
temp = Math.Max(temp, v);
Board.RemoveTopCoinFromCol(i);
}
}
}
else
{
temp = 1000;
for (int i = 0; i < Board.Cols; i++)
{
if (Board.FillSignInBoardAccordingToCol(i, PlayerSign)) // so we don't open another branch in a full column
{
var v = MinMax(Depth - 1, Board, otherPlayerSign);
temp = Math.Min(temp, v);
Board.RemoveTopCoinFromCol(i);
}
}
}
return temp;
}
一些说明：
如果成功， FillSignInBoardAccordingToCol()返回一个布尔值。
board类型有一个char[,]阵列，其中包含球员的实际棋盘和标志。
此代码位于AI Player类中。
所以我决定编写自己的MinMax Connect 4.我使用深度来确定赢或输的价值，以便让您更接近获胜或阻止损失的举动将优先。 我还决定，如果不止一个人具有相同的启发式，我会随机选择。 最后，我将深度延伸至6，因为从一开始就需要进行多少次移动才能找到可能的胜出路线。
private static void Main(string[] args)
{
var board = new Board(8,7);
var random = new Random();
while (true)
{
Console.WriteLine("Pick a column 1 -8");
int move;
if (!int.TryParse(Console.ReadLine(), out move) || move < 1 || move > 8)
{
Console.WriteLine("Must enter a number 1-8.");
continue;
}
if (!board.DropCoin(1, move-1))
{
Console.WriteLine("That column is full, pick another one");
continue;
}
if (board.Winner == 1)
{
Console.WriteLine(board);
Console.WriteLine("You win!");
break;
}
if (board.IsFull)
{
Console.WriteLine(board);
Console.WriteLine("Tie!");
break;
}
var moves = new List<Tuple<int, int>>();
for (int i = 0; i < board.Columns; i++)
{
if (!board.DropCoin(2, i))
continue;
moves.Add(Tuple.Create(i, MinMax(6, board, false)));
board.RemoveTopCoin(i);
}
int maxMoveScore = moves.Max(t => t.Item2);
var bestMoves = moves.Where(t => t.Item2 == maxMoveScore).ToList();
board.DropCoin(2, bestMoves[random.Next(0,bestMoves.Count)].Item1);
Console.WriteLine(board);
if (board.Winner == 2)
{
Console.WriteLine("You lost!");
break;
}
if (board.IsFull)
{
Console.WriteLine("Tie!");
break;
}
}
Console.WriteLine("DONE");
Console.ReadKey();
}
private static int MinMax(int depth, Board board, bool maximizingPlayer)
{
if (depth <= 0)
return 0;
var winner = board.Winner;
if (winner == 2)
return depth;
if (winner == 1)
return -depth;
if (board.IsFull)
return 0;
int bestValue = maximizingPlayer ? -1 : 1;
for (int i = 0; i < board.Columns; i++)
{
if (!board.DropCoin(maximizingPlayer ? 2 : 1, i))
continue;
int v = MinMax(depth - 1, board, !maximizingPlayer);
bestValue = maximizingPlayer ? Math.Max(bestValue, v) : Math.Min(bestValue, v);
board.RemoveTopCoin(i);
}
return bestValue;
}
public class Board
{
private readonly int?[,] _board;
private int? _winner;
private bool _changed;
public Board(int cols, int rows)
{
Columns = cols;
Rows = rows;
_board = new int?[cols, rows];
}
public int Columns { get; }
public int Rows { get; }
public bool ColumnFree(int column)
{
return !_board[column, 0].HasValue;
}
public bool DropCoin(int playerId, int column)
{
int row = 0;
while (row < Rows && !_board[column,row].HasValue)
{
row++;
}
if (row == 0)
return false;
_board[column, row - 1] = playerId;
_changed = true;
return true;
}
public bool RemoveTopCoin(int column)
{
int row = 0;
while (row < Rows && !_board[column, row].HasValue)
{
row++;
}
if (row == Rows)
return false;
_board[column, row] = null;
_changed = true;
return true;
}
public int? Winner
{
get
{
if (!_changed)
return _winner;
_changed = false;
for (int i = 0; i < Columns; i++)
{
for (int j = 0; j < Rows; j++)
{
if (!_board[i, j].HasValue)
continue;
bool horizontal = i + 3 < Columns;
bool vertical = j + 3 < Rows;
if (!horizontal && !vertical)
continue;
bool forwardDiagonal = horizontal && vertical;
bool backwardDiagonal = vertical && i - 3 >= 0;
for (int k = 1; k < 4; k++)
{
horizontal = horizontal && _board[i, j] == _board[i + k, j];
vertical = vertical && _board[i, j] == _board[i, j + k];
forwardDiagonal = forwardDiagonal && _board[i, j] == _board[i + k, j + k];
backwardDiagonal = backwardDiagonal && _board[i, j] == _board[i - k, j + k];
if (!horizontal && !vertical && !forwardDiagonal && !backwardDiagonal)
break;
}
if (horizontal || vertical || forwardDiagonal || backwardDiagonal)
{
_winner = _board[i, j];
return _winner;
}
}
}
_winner = null;
return _winner;
}
}
public bool IsFull
{
get
{
for (int i = 0; i < Columns; i++)
{
if (!_board[i, 0].HasValue)
return false;
}
return true;
}
}
public override string ToString()
{
var builder = new StringBuilder();
for (int j = 0; j < Rows; j++)
{
builder.Append('|');
for (int i = 0; i < Columns; i++)
{
builder.Append(_board[i, j].HasValue ? _board[i,j].Value.ToString() : " ").Append('|');
}
builder.AppendLine();
}
return builder.ToString();
}
}
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