六子棋建立博弈树α-β剪枝算法代码C语言

下面是六子棋建立博弈树α-β剪枝算法的代码，使用C语言实现：

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

#define BOARD_SIZE 6
#define EMPTY 0
#define PLAYER1 1
#define PLAYER2 2

int board[BOARD_SIZE][BOARD_SIZE];

// 判断当前棋盘状态下是否有玩家获胜
int is_win(int player) {
    int i, j, k;

    // 横向检查
    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE - 5; j++) {
            for (k = 0; k < 6; k++) {
                if (board[i][j + k] != player) {
                    break;
                }
            }
            if (k == 6) {
                return 1;
            }
        }
    }

    // 竖向检查
    for (i = 0; i < BOARD_SIZE - 5; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            for (k = 0; k < 6; k++) {
                if (board[i + k][j] != player) {
                    break;
                }
            }
            if (k == 6) {
                return 1;
            }
        }
    }

    // 左上到右下斜线检查
    for (i = 0; i < BOARD_SIZE - 5; i++) {
        for (j = 0; j < BOARD_SIZE - 5; j++) {
            for (k = 0; k < 6; k++) {
                if (board[i + k][j + k] != player) {
                    break;
                }
            }
            if (k == 6) {
                return 1;
            }
        }
    }

    // 右上到左下斜线检查
    for (i = 5; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE - 5; j++) {
            for (k = 0; k < 6; k++) {
                if (board[i - k][j + k] != player) {
                    break;
                }
            }
            if (k == 6) {
                return 1;
            }
        }
    }

    return 0;
}

// 计算当前棋盘状态的得分
int evaluate_board() {
    int i, j, k, player1_score, player2_score;

    // 横向得分
    player1_score = player2_score = 0;
    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE - 5; j++) {
            int player1_count = 0, player2_count = 0;
            for (k = 0; k < 6; k++) {
                if (board[i][j + k] == PLAYER1) {
                    player1_count++;
                } else if (board[i][j + k] == PLAYER2) {
                    player2_count++;
                }
            }
            if (player1_count > 0 && player2_count == 0) {
                player1_score += 10;
            } else if (player2_count > 0 && player1_count == 0) {
                player2_score += 10;
            }
        }
    }

    // 竖向得分
    for (i = 0; i < BOARD_SIZE - 5; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            int player1_count = 0, player2_count = 0;
            for (k = 0; k < 6; k++) {
                if (board[i + k][j] == PLAYER1) {
                    player1_count++;
                } else if (board[i + k][j] == PLAYER2) {
                    player2_count++;
                }
            }
            if (player1_count > 0 && player2_count == 0) {
                player1_score += 10;
            } else if (player2_count > 0 && player1_count == 0) {
                player2_score += 10;
            }
        }
    }

    // 左上到右下斜线得分
    for (i = 0; i < BOARD_SIZE - 5; i++) {
        for (j = 0; j < BOARD_SIZE - 5; j++) {
            int player1_count = 0, player2_count = 0;
            for (k = 0; k < 6; k++) {
                if (board[i + k][j + k] == PLAYER1) {
                    player1_count++;
                } else if (board[i + k][j + k] == PLAYER2) {
                    player2_count++;
                }
            }
            if (player1_count > 0 && player2_count == 0) {
                player1_score += 10;
            } else if (player2_count > 0 && player1_count == 0) {
                player2_score += 10;
            }
        }
    }

    // 右上到左下斜线得分
    for (i = 5; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE - 5; j++) {
            int player1_count = 0, player2_count = 0;
            for (k = 0; k < 6; k++) {
                if (board[i - k][j + k] == PLAYER1) {
                    player1_count++;
                } else if (board[i - k][j + k] == PLAYER2) {
                    player2_count++;
                }
            }
            if (player1_count > 0 && player2_count == 0) {
                player1_score += 10;
            } else if (player2_count > 0 && player1_count == 0) {
                player2_score += 10;
            }
        }
    }

    return player1_score - player2_score;
}

// 枚举所有空位，计算当前玩家的得分
int alpha_beta_search(int alpha, int beta, int depth, int player) {
    int i, j, value, best_value;

    if (is_win(PLAYER1)) {
        return INT_MAX;
    } else if (is_win(PLAYER2)) {
        return INT_MIN;
    } else if (depth == 0) {
        return evaluate_board();
    }

    if (player == PLAYER1) {
        best_value = INT_MIN;
        for (i = 0; i < BOARD_SIZE; i++) {
            for (j = 0; j < BOARD_SIZE; j++) {
                if (board[i][j] == EMPTY) {
                    board[i][j] = PLAYER1;
                    value = alpha_beta_search(alpha, beta, depth - 1, PLAYER2);
                    board[i][j] = EMPTY;
                    if (value > best_value) {
                        best_value = value;
                    }
                    if (best_value > alpha) {
                        alpha = best_value;
                    }
                    if (alpha >= beta) {
                        return best_value;
                    }
                }
            }
        }
    } else {
        best_value = INT_MAX;
        for (i = 0; i < BOARD_SIZE; i++) {
            for (j = 0; j < BOARD_SIZE; j++) {
                if (board[i][j] == EMPTY) {
                    board[i][j] = PLAYER2;
                    value = alpha_beta_search(alpha, beta, depth - 1, PLAYER1);
                    board[i][j] = EMPTY;
                    if (value < best_value) {
                        best_value = value;
                    }
                    if (best_value < beta) {
                        beta = best_value;
                    }
                    if (alpha >= beta) {
                        return best_value;
                    }
                }
            }
        }
    }

    return best_value;
}

// 根据当前玩家的得分，找到最佳落子位置
void find_best_move(int *x, int *y) {
    int i, j, value, best_value;

    *x = *y = -1;
    best_value = INT_MIN;

    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[i][j] == EMPTY) {
                board[i][j] = PLAYER1;
                value = alpha_beta_search(INT_MIN, INT_MAX, 5, PLAYER2);
                board[i][j] = EMPTY;
                if (value > best_value) {
                    best_value = value;
                    *x = i;
                    *y = j;
                }
            }
        }
    }
}

int main() {
    int i, j, x, y;

    // 初始化棋盘
    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            board[i][j] = EMPTY;
        }
    }

    // 玩家和AI轮流下棋，直到有一方获胜或棋盘已满
    while (!is_win(PLAYER1) && !is_win(PLAYER2)) {
        // 玩家下棋
        printf("Enter your move (row column): ");
        scanf("%d %d", &x, &y);
        if (board[x][y] != EMPTY) {
            printf("Invalid move!\n");
            continue;
        }
        board[x][y] = PLAYER2;

        // AI下棋
        find_best_move(&x, &y);
        board[x][y] = PLAYER1;

        // 输出当前棋盘状态
        for (i = 0; i < BOARD_SIZE; i++) {
            for (j = 0; j < BOARD_SIZE; j++) {
                printf("%d ", board[i][j]);
            }
            printf("\n");
        }
        printf("\n");
    }

    // 输出获胜者
    if (is_win(PLAYER1)) {
        printf("AI wins!\n");
    } else if (is_win(PLAYER2)) {
        printf("You win!\n");
    } else {
        printf("Draw!\n");
    }

    return 0;
}

注意，这只是一个简单的示例代码，可能存在一些问题和需要完善的地方。如果你想使用这个代码进行实际的游戏，需要进一步优化和改进。