六子棋的alpha-beta剪枝java代码

下面是六子棋的alpha-beta剪枝Java代码：

public class AlphaBetaPruning {

    private static final int MAX_DEPTH = 5;
    private static final int WIN_SCORE = 100000;
    private static final int[][] DIRECTIONS = {{1, 0}, {0, 1}, {1, 1}, {1, -1}};

    public int[] getBestMove(int[][] board) {
        int bestScore = Integer.MIN_VALUE;
        int[] bestMove = new int[2];

        for (int i = 0; i < board.length; i++) {
            for (int j = 0; j < board[0].length; j++) {
                if (board[i][j] == 0) {
                    board[i][j] = 1;
                    int score = alphaBeta(board, MAX_DEPTH, Integer.MIN_VALUE, Integer.MAX_VALUE, false);
                    board[i][j] = 0;

                    if (score > bestScore) {
                        bestScore = score;
                        bestMove[0] = i;
                        bestMove[1] = j;
                    }
                }
            }
        }

        return bestMove;
    }

    private int alphaBeta(int[][] board, int depth, int alpha, int beta, boolean isMaxPlayer) {
        int score = evaluate(board);

        if (score == WIN_SCORE || score == -WIN_SCORE || depth == 0) {
            return score;
        }

        if (isMaxPlayer) {
            int maxScore = Integer.MIN_VALUE;

            for (int i = 0; i < board.length; i++) {
                for (int j = 0; j < board[0].length; j++) {
                    if (board[i][j] == 0) {
                        board[i][j] = 1;
                        int currentScore = alphaBeta(board, depth - 1, alpha, beta, false);
                        board[i][j] = 0;
                        maxScore = Math.max(maxScore, currentScore);
                        alpha = Math.max(alpha, currentScore);

                        if (beta <= alpha) {
                            return maxScore;
                        }
                    }
                }
            }

            return maxScore;
        } else {
            int minScore = Integer.MAX_VALUE;

            for (int i = 0; i < board.length; i++) {
                for (int j = 0; j < board[0].length; j++) {
                    if (board[i][j] == 0) {
                        board[i][j] = 2;
                        int currentScore = alphaBeta(board, depth - 1, alpha, beta, true);
                        board[i][j] = 0;
                        minScore = Math.min(minScore, currentScore);
                        beta = Math.min(beta, currentScore);

                        if (beta <= alpha) {
                            return minScore;
                        }
                    }
                }
            }

            return minScore;
        }
    }

    private int evaluate(int[][] board) {
        int score = 0;

        // Check rows
        for (int i = 0; i < board.length; i++) {
            score += evaluateLine(board[i]);
        }

        // Check columns
        for (int j = 0; j < board[0].length; j++) {
            int[] column = new int[board.length];

            for (int i = 0; i < board.length; i++) {
                column[i] = board[i][j];
            }

            score += evaluateLine(column);
        }

        // Check diagonals
        for (int i = 0; i < board.length; i++) {
            for (int j = 0; j < board[0].length; j++) {
                for (int[] direction : DIRECTIONS) {
                    int x = i + direction[0] * 5;
                    int y = j + direction[1] * 5;

                    if (x >= 0 && x < board.length && y >= 0 && y < board[0].length) {
                        int[] diagonal = new int[6];

                        for (int k = 0; k < 6; k++) {
                            diagonal[k] = board[i + direction[0] * k][j + direction[1] * k];
                        }

                        score += evaluateLine(diagonal);
                    }
                }
            }
        }

        return score;
    }

    private int evaluateLine(int[] line) {
        int humanCount = 0;
        int computerCount = 0;

        for (int i = 0; i < line.length; i++) {
            if (line[i] == 1) {
                humanCount++;
            } else if (line[i] == 2) {
                computerCount++;
            }
        }

        if (humanCount == 0) {
            return (int) Math.pow(10, computerCount);
        } else if (computerCount == 0) {
            return -(int) Math.pow(10, humanCount);
        }

        return 0;
    }
}

这段代码使用了递归实现了alpha-beta剪枝算法，其中`getBestMove`方法返回最佳下棋位置，`alphaBeta`方法返回当前局面下的最大得分或最小得分，`evaluate`方法计算局面得分，`evaluateLine`方法计算一行、一列或一条对角线的得分。