C语言实现六子棋使用α-β剪枝算法的代码

以下是使用α-β剪枝算法实现的C语言六子棋代码：

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

#define BOARD_SIZE 6
#define MAX_DEPTH 5

typedef struct {
    int row;
    int col;
} Move;

int board[BOARD_SIZE][BOARD_SIZE];
int player = 1; // 1 for player 1, -1 for player 2
int maxDepth = MAX_DEPTH;

int evaluate() {
    int score = 0;
    int i, j;
    // check rows
    for (i = 0; i < BOARD_SIZE; i++) {
        int count = 0;
        int openEnds = 0;
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[i][j] == player) {
                count++;
            } else if (board[i][j] == -player) {
                if (count == 0) {
                    openEnds++;
                } else {
                    score += count * count;
                    count = 0;
                }
            } else if (count > 0) {
                openEnds++;
                count = 0;
            }
        }
        if (count > 0) {
            score += count * count;
        }
        if (openEnds == 2) {
            score += 1;
        }
    }
    // check columns
    for (j = 0; j < BOARD_SIZE; j++) {
        int count = 0;
        int openEnds = 0;
        for (i = 0; i < BOARD_SIZE; i++) {
            if (board[i][j] == player) {
                count++;
            } else if (board[i][j] == -player) {
                if (count == 0) {
                    openEnds++;
                } else {
                    score += count * count;
                    count = 0;
                }
            } else if (count > 0) {
                openEnds++;
                count = 0;
            }
        }
        if (count > 0) {
            score += count * count;
        }
        if (openEnds == 2) {
            score += 1;
        }
    }
    // check diagonals
    for (i = 0; i < BOARD_SIZE; i++) {
        int count = 0;
        int openEnds = 0;
        for (j = 0; j < BOARD_SIZE - i; j++) {
            if (board[i+j][j] == player) {
                count++;
            } else if (board[i+j][j] == -player) {
                if (count == 0) {
                    openEnds++;
                } else {
                    score += count * count;
                    count = 0;
                }
            } else if (count > 0) {
                openEnds++;
                count = 0;
            }
        }
        if (count > 0) {
            score += count * count;
        }
        if (openEnds == 2) {
            score += 1;
        }
    }
    for (j = 1; j < BOARD_SIZE; j++) {
        int count = 0;
        int openEnds = 0;
        for (i = 0; i < BOARD_SIZE - j; i++) {
            if (board[i][j+i] == player) {
                count++;
            } else if (board[i][j+i] == -player) {
                if (count == 0) {
                    openEnds++;
                } else {
                    score += count * count;
                    count = 0;
                }
            } else if (count > 0) {
                openEnds++;
                count = 0;
            }
        }
        if (count > 0) {
            score += count * count;
        }
        if (openEnds == 2) {
            score += 1;
        }
    }
    for (i = 0; i < BOARD_SIZE; i++) {
        int count = 0;
        int openEnds = 0;
        for (j = 0; j <= i; j++) {
            if (board[i-j][j] == player) {
                count++;
            } else if (board[i-j][j] == -player) {
                if (count == 0) {
                    openEnds++;
                } else {
                    score += count * count;
                    count = 0;
                }
            } else if (count > 0) {
                openEnds++;
                count = 0;
            }
        }
        if (count > 0) {
            score += count * count;
        }
        if (openEnds == 2) {
            score += 1;
        }
    }
    for (j = 1; j < BOARD_SIZE; j++) {
        int count = 0;
        int openEnds = 0;
        for (i = BOARD_SIZE - 1; i >= j; i--) {
            if (board[i][j+(BOARD_SIZE-1-i)] == player) {
                count++;
            } else if (board[i][j+(BOARD_SIZE-1-i)] == -player) {
                if (count == 0) {
                    openEnds++;
                } else {
                    score += count * count;
                    count = 0;
                }
            } else if (count > 0) {
                openEnds++;
                count = 0;
            }
        }
        if (count > 0) {
            score += count * count;
        }
        if (openEnds == 2) {
            score += 1;
        }
    }
    return score;
}

int isGameOver() {
    int i, j;
    // check rows
    for (i = 0; i < BOARD_SIZE; i++) {
        int count = 0;
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[i][j] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count == 6) {
                return 1;
            }
        }
    }
    // check columns
    for (j = 0; j < BOARD_SIZE; j++) {
        int count = 0;
        for (i = 0; i < BOARD_SIZE; i++) {
            if (board[i][j] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count == 6) {
                return 1;
            }
        }
    }
    // check diagonals
    for (i = 0; i < BOARD_SIZE; i++) {
        int count = 0;
        for (j = 0; j < BOARD_SIZE - i; j++) {
            if (board[i+j][j] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count == 6) {
                return 1;
            }
        }
    }
    for (j = 1; j < BOARD_SIZE; j++) {
        int count = 0;
        for (i = 0; i < BOARD_SIZE - j; i++) {
            if (board[i][j+i] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count == 6) {
                return 1;
            }
        }
    }
    for (i = 0; i < BOARD_SIZE; i++) {
        int count = 0;
        for (j = 0; j <= i; j++) {
            if (board[i-j][j] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count == 6) {
                return 1;
            }
        }
    }
    for (j = 1; j < BOARD_SIZE; j++) {
        int count = 0;
        for (i = BOARD_SIZE - 1; i >= j; i--) {
            if (board[i][j+(BOARD_SIZE-1-i)] == player) {
                count++;
            } else {
                count = 0;
            }
            if (count == 6) {
                return 1;
            }
        }
    }
    // check for tie
    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[i][j] == 0) {
                return 0;
            }
        }
    }
    return 1;
}

int minimax(int depth, int alpha, int beta) {
    int i, j, score, bestScore;
    Move move;
    bestScore = -player*10000;
    if (depth == maxDepth || isGameOver()) {
        return evaluate();
    }
    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[i][j] == 0) {
                board[i][j] = player;
                move.row = i;
                move.col = j;
                score = -minimax(depth+1, -beta, -alpha);
                board[i][j] = 0;
                if (score > bestScore) {
                    bestScore = score;
                    if (depth == 0) {
                        printf("Best move: row=%d col=%d score=%d\n", i, j, score);
                    }
                }
                if (score > alpha) {
                    alpha = score;
                }
                if (alpha >= beta) {
                    return alpha;
                }
            }
        }
    }
    return bestScore;
}

void makeMove() {
    int i, j, score, bestScore;
    Move move, bestMove;
    bestScore = -player*10000;
    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[i][j] == 0) {
                board[i][j] = player;
                move.row = i;
                move.col = j;
                score = -minimax(1, -player*10000, player*10000);
                board[i][j] = 0;
                if (score > bestScore) {
                    bestScore = score;
                    bestMove = move;
                }
            }
        }
    }
    board[bestMove.row][bestMove.col] = player;
    printf("Player %d moved: row=%d col=%d\n", player, bestMove.row, bestMove.col);
}

void printBoard() {
    int i, j;
    for (i = 0; i < BOARD_SIZE; i++) {
        for (j = 0; j < BOARD_SIZE; j++) {
            if (board[i][j] == 1) {
                printf("X ");
            } else if (board[i][j] == -1) {
                printf("O ");
            } else {
                printf("- ");
            }
        }
        printf("\n");
    }
}

int main() {
    int i, j;
    memset(board, 0, sizeof(board));
    printf("Starting game...\n");
    while (!isGameOver()) {
        printBoard();
        if (player == 1) {
            makeMove();
            player = -1;
        } else {
            printf("Enter row and column for player 2: ");
            scanf("%d %d", &i, &j);
            board[i][j] = -1;
            player = 1;
        }
    }
    printBoard();
    if (evaluate() > 0) {
        printf("Player 1 wins!\n");
    } else if (evaluate() < 0) {
        printf("Player 2 wins!\n");
    } else {
        printf("Tie game!\n");
    }
    return 0;
}

该代码使用了α-β剪枝算法来搜索最优解，其中evaluate()函数用于评估当前局面的得分，isGameOver()函数用于判断游戏是否结束，minimax()函数用于实现α-β剪枝算法，makeMove()函数用于让电脑进行移动，printBoard()函数用于打印当前棋盘。该代码实现了一个简单的人机对战六子棋游戏，可以通过调整maxDepth来控制搜索深度，从而影响电脑的水平。