java - Java 中的 Minimax 不起作用

Question

我正在尝试让我的极小极大算法适用于 8x8 五子棋棋盘，我必须连续匹配 5 个/列/对角线才能获胜!我的算法似乎没有正常工作，我无法查明哪里出错了!

我的 generateMoves() 方法工作正常，它生成所有合法的移动，所以我知道它不是那样的。 minimax 返回 -1,-1 作为最佳着法，但那当然会引发 illegalMove 错误，因为你不能在从 0,0 到 7,7 的棋盘上有 -1,-1。

感谢任何帮助。谢谢。

 private int[] minimax(int depth, Color [][] board) {
          List<int[]> nextMoves = generateMoves(board);

          int bestScore = (me == Color.WHITE) ? Integer.MIN_VALUE : Integer.MAX_VALUE;
          int currentScore;
          int bestRow = -1;
          int bestCol = -1;

          if (nextMoves.isEmpty() || depth == 0) {
             bestScore = evaluateBoard(board);
          } else {
             for (int[] move : nextMoves) {
                 System.out.println(move[0]+","+move[1]+" THIS WAS ATTEMPTED");
                 board[move[0]][move[1]] = Color.WHITE;
                if (me == Color.BLACK) {  
                   currentScore = minimax(depth - 1, board)[0];
                   if (currentScore > bestScore) {
                      bestScore = currentScore;
                      bestRow = move[0];
                      bestCol = move[1];
                   }
                } else {  // oppSeed is minimizing player
                   currentScore = minimax(depth - 1, board)[0];
                   if (currentScore < bestScore) {
                      bestScore = currentScore;
                      bestRow = move[0];
                      bestCol = move[1];
                   }
                }
                board[move[0]][move[1]] = null;
             }
          }
          return new int[] {bestRow, bestCol};
       }

public int evaluateBoard(Color[][] board) {
    int score = 0;
    // Check all the rows
    for (int i = 0; i < 8; i++) {
        int blank = 0;
        int black = 0;
        int white = 0;
        for (int j = 0; j < 8 - 5; ++j) {
            if (board[i][j] == Color.black) {
                black++;
                if (board[i][j + 1] == Color.BLACK) {
                    black++;
                    if (board[i][j + 2] == Color.BLACK) {
                        if (board[i][j + 3] == Color.BLACK) {
                            black++;
                            if (board[i][j + 4] == Color.BLACK) {
                                black++;
                            }
                        }
                    }
                }
            } else if (board[i][j] == Color.WHITE) {
                white++;
                if (board[i][j + 1] == Color.WHITE) {
                    white++;
                    if (board[i][j + 2] == Color.WHITE) {
                        white++;
                        if (board[i][j + 3] == Color.WHITE) {
                            white++;
                            if (board[i][j + 4] == Color.WHITE) {
                                white++;
                            }
                        }
                    }
                }
            }
        }
        System.out.println(black);
        score += scoreChange(black, white);
    }

    // Check all the columns
    for (int j = 0; j < 8; ++j) {
        int blank = 0;
        int black = 0;
        int white = 0;
        for (int i = 0; i < 8 - 5; ++i) {
            if (board[i][j] == Color.black) {
                black++;
                if (board[i + 1][j] == Color.BLACK) {
                    black++;
                    if (board[i + 2][j] == Color.BLACK) {
                        black++;
                        if (board[i + 3][j] == Color.BLACK) {
                            black++;
                            if (board[i + 4][j] == Color.BLACK) {
                                black++;
                            }
                        }
                    }
                }
            } else if (board[i][j] == Color.WHITE) {
                white++;
                if (board[i + 1][j] == Color.WHITE) {
                    white++;
                    if (board[i + 2][j] == Color.WHITE) {
                        white++;
                        if (board[i + 3][j] == Color.WHITE) {
                            white++;
                            if (board[i + 4][j] == Color.WHITE) {
                                white++;
                            }
                        }
                    }
                }
            }
        }
        score += scoreChange(black, white);
    }

    int black = 0;
    int white = 0;
    // Check diagonal (Second)
    for (int i = 7, j = 0; i > 3; --i, ++j) {
        if (board[i][j] == Color.black) {
            black++;
            if (board[i - 1][j + 1] == Color.black) {
                black++;
                if (board[i - 2][j + 2] == Color.black) {
                    black++;
                    if (board[i - 3][j + 3] == Color.black) {
                        black++;
                        if (board[i - 4][j + 4] == Color.black) {
                            black++;
                        }
                    }
                }
            }
        } else if (board[i][j] == Color.white) {
            white++;
            if (board[i - 1][j + 1] == Color.white) {
                white++;
                if (board[i - 2][j + 2] == Color.white) {
                    white++;
                    if (board[i - 3][j + 3] == Color.white) {
                        white++;
                        if (board[i - 4][j + 4] == Color.white) {
                            white++;
                        }
                    }
                }
            }
        }
    }
    score += scoreChange(black, white);

    black = 0;
    white = 0;
    // Check Diagonal (First)
    for (int i = 0, j = 0; i < 4; ++i, ++j) {
        if (board[i][j] == Color.black) {
            black++;
            if (board[i + 1][j + 1] == Color.black) {
                black++;
                if (board[i + 2][j + 2] == Color.black) {
                    black++;
                    if (board[i + 3][j + 3] == Color.black) {
                        black++;
                        if (board[i + 4][j + 4] == Color.black) {
                            black++;
                        }
                    }
                }
            }
        } else if (board[i][j] == Color.white) {
            white++;
            if (board[i + 1][j + 1] == Color.white) {
                white++;
                if (board[i + 2][j + 2] == Color.white) {
                    white++;
                    if (board[i + 3][j + 3] == Color.white) {
                        white++;
                        if (board[i + 4][j + 4] == Color.white) {
                            white++;
                        }
                    }
                }
            }
        }
    }
    score += scoreChange(black, white);
    return score;
}

private int scoreChange(int black, int white) {
    int change;

    if (black == 5) {
        change = -10000;
    } else if (black == 4 && white == 0) {
        change = -1000;
    } else if (black == 3 && white == 0) {
        change = -100;
    } else if (black == 2 && white == 0) {
        change = -10;
    } else if (black == 1 && white == 0) {
        change = -1;
    } else if (white == 5) {
        change = 10000;
    } else if (white == 4 && black == 0) {
        change = 1000;
    } else if (white == 3 && black == 0) {
        change = 100;
    } else if (white == 2 && black == 0) {
        change = 10;
    } else if (white == 1 && black == 0) {
        change = 1;
    } else {
        change = 0;
    }
    return change;
}

Answer 1

如果玩家是黑色，最好的分数是 Integer.Max。当前分数永远不会大于该分数，因此永远不会设置最佳着法。对于怀特，问题是一致的:最好的分数是 Integer.Min，当前分数永远不会更小。

使用调试器查找此类错误要容易得多。设置一个断点，将移动设置为 -1，然后向前迈进。当您接触到这些 if 语句时，您会惊讶地发现您的代码没有介入。您将仔细查看所比较的值，然后意识到您的错误。