class Solution {
    final int[][] adjacent = {{-1,-1}, {-1, 0}, {-1, 1}, {0, -1}, {0, 1},{1, -1}, {1, 0}, {1, 1}};

    public char[][] updateBoard(char[][] board, int[] click) {
        if(board == null || click == null ||
           board.length == 0 || board[0].length == 0 || click.length == 0)
            return board;
        int i = click[0], j = click[1];
        if(board[i][j] == 'M'){
            board[i][j] = 'X';
            return board;
        }
        dfs(board, i, j);
        return board;
    }

    void dfs(char[][] board, int i, int j){
        if(i < 0 || j < 0 || i >= board.length || j >= board[0].length
               || board[i][j] != 'E')
            return;
        board[i][j] = countM(board, i, j);
        if(board[i][j] != 'B') return;
        for(int[] dir: adjacent)
            dfs(board, i + dir[0], j + dir[1]);
    }

    char countM(char[][] board, int i, int j){
        int count = 0;
        for(int[] dir: adjacent){
            int r = i + dir[0];
            int c = j + dir[1];
            if(r >=0 && c >=0
               && r < board.length && c < board[0].length
               && board[r][c] == 'M')
                count++;
        }
        return (count == 0) ? 'B' : ((char) ('0' + count));
    }
}