六子棋博弈树C语言代码实现

六子棋博弈树的实现可以使用alpha-beta剪枝算法来提高搜索效率。以下是一个简单的C语言代码实现：

#include <stdio.h>

#define ROW 6
#define COL 6
#define MAX_DEPTH 3

int board[ROW][COL] = {0}; // 棋盘
int max_score = 100; // 最大分数
int min_score = -100; // 最小分数

// 判断是否赢了
int check_win(int player) {
    int i, j, count;
    // 横向判断
    for (i = 0; i < ROW; i++) {
        count = 0;
        for (j = 0; j < COL; j++) {
            if (board[i][j] == player) {
                count++;
                if (count == 6) {
                    return 1;
                }
            } else {
                count = 0;
            }
        }
    }
    // 纵向判断
    for (j = 0; j < COL; j++) {
        count = 0;
        for (i = 0; i < ROW; i++) {
            if (board[i][j] == player) {
                count++;
                if (count == 6) {
                    return 1;
                }
            } else {
                count = 0;
            }
        }
    }
    // 斜向判断
    for (i = 0; i < ROW - 5; i++) {
        for (j = 0; j < COL - 5; j++) {
            if (board[i][j] == player && board[i+1][j+1] == player && board[i+2][j+2] == player
                    && board[i+3][j+3] == player && board[i+4][j+4] == player && board[i+5][j+5] == player) {
                return 1;
            }
            if (board[i][j+5] == player && board[i+1][j+4] == player && board[i+2][j+3] == player
                    && board[i+3][j+2] == player && board[i+4][j+1] == player && board[i+5][j] == player) {
                return 1;
            }
        }
    }
    return 0;
}

// 评估当前局面分数
int evaluate(int player) {
    if (check_win(player)) {
        return max_score;
    } else if (check_win(3-player)) {
        return min_score;
    } else {
        // 计算当前局面分数
        int i, j, score = 0;
        for (i = 0; i < ROW; i++) {
            for (j = 0; j < COL; j++) {
                if (board[i][j] == player) {
                    score++;
                } else if (board[i][j] == 3-player) {
                    score--;
                }
            }
        }
        return score;
    }
}

// alpha-beta剪枝搜索算法
int alpha_beta(int depth, int alpha, int beta, int player) {
    if (depth == 0) {
        return evaluate(player);
    }
    int i, j, score;
    if (player == 1) {
        for (i = 0; i < ROW; i++) {
            for (j = 0; j < COL; j++) {
                if (board[i][j] == 0) {
                    board[i][j] = player;
                    score = alpha_beta(depth-1, alpha, beta, 3-player);
                    board[i][j] = 0;
                    if (score > alpha) {
                        alpha = score;
                    }
                    if (alpha >= beta) {
                        return alpha;
                    }
                }
            }
        }
        return alpha;
    } else {
        for (i = 0; i < ROW; i++) {
            for (j = 0; j < COL; j++) {
                if (board[i][j] == 0) {
                    board[i][j] = player;
                    score = alpha_beta(depth-1, alpha, beta, 3-player);
                    board[i][j] = 0;
                    if (score < beta) {
                        beta = score;
                    }
                    if (alpha >= beta) {
                        return beta;
                    }
                }
            }
        }
        return beta;
    }
}

// 电脑下棋
void computer_play(int player) {
    int i, j, max_score = min_score, score;
    int x, y;
    for (i = 0; i < ROW; i++) {
        for (j = 0; j < COL; j++) {
            if (board[i][j] == 0) {
                board[i][j] = player;
                score = alpha_beta(MAX_DEPTH, min_score, max_score, 3-player);
                board[i][j] = 0;
                if (score > max_score) {
                    max_score = score;
                    x = i;
                    y = j;
                }
            }
        }
    }
    board[x][y] = player;
}

// 打印棋盘
void print_board() {
    int i, j;
    for (i = 0; i < ROW; i++) {
        for (j = 0; j < COL; j++) {
            printf("%c ", board[i][j] == 0 ? '-' : board[i][j] == 1 ? 'X' : 'O');
        }
        printf("\n");
    }
    printf("\n");
}

int main() {
    int player = 1; // 玩家先手
    int x, y;
    while (1) {
        if (player == 1) {
            printf("请玩家输入下棋位置(x,y):");
            scanf("%d,%d", &x, &y);
            if (board[x][y] != 0) {
                printf("该位置已有棋子，请重新输入！\n");
                continue;
            }
            board[x][y] = player;
        } else {
            computer_play(player);
        }
        print_board();
        if (check_win(player)) {
            printf("恭喜玩家%d胜利！\n", player);
            break;
        }
        if (player == 1) {
            player = 2;
        } else {
            player = 1;
        }
    }
    return 0;
}

以上代码实现了一个简单的六子棋博弈树，玩家可以与电脑进行对弈。其中alpha-beta剪枝算法可以大大提高搜索效率，使得电脑更加智能。