扫雷游戏

/*
 * 思路：
 * 1. 利用Java Stream API实现矩阵的遍历与更新。
 * 2. 使用Stream的foreach和map等操作对矩阵元素进行处理。
 */
 
import java.util.stream.IntStream;
 
public class MinesweeperStream {
    private static final int[][] directions = {
        {-1, -1}, {-1, 0}, {-1, 1},
        {0, -1},           {0, 1},
        {1, -1}, {1, 0}, {1, 1}
    };
 
    public char[][] updateBoard(char[][] board, int[] click) {
        int row = click[0], col = click[1];
        if (board[row][col] == 'M') {
            board[row][col] = 'X';
        } else {
            IntStream.range(0, board.length).forEach(r ->
                IntStream.range(0, board[0].length).forEach(c ->
                    dfs(board, row, col)));
        }
        return board;
    }
 
    private void dfs(char[][] board, int row, int col) {
        if (row < 0 || row >= board.length || col < 0 || col >= board[0].length || board[row][col] != 'E') {
            return;
        }
 
        long mineCount = IntStream.range(0, directions.length)
            .mapToObj(i -> directions[i])
            .filter(dir -> {
                int newRow = row + dir[0], newCol = col + dir[1];
                return newRow >= 0 && newRow < board.length && newCol >= 0 && newCol < board[0].length && board[newRow][newCol] == 'M';
            }).count();
 
        if (mineCount > 0) {
            board[row][col] = (char) ('0' + mineCount);
        } else {
            board[row][col] = 'B';
            IntStream.range(0, directions.length).forEach(i -> {
                int[] dir = directions[i];
                dfs(board, row + dir[0], col + dir[1]);
            });
        }
    }
}