原题链接：Leecode 529. 扫雷游戏

class Solution {
public:
    vector<vector<int>> vis;
    int x[8]={-1,-1,-1,1,1,1,0,0};
    int y[8]={-1,0,1,-1,0,1,-1,1};
    int fun(vector<vector<char>>& board,int i,int j)
    {
        int m=board.size(),n=board[0].size();
        if(i<0 || i>m-1 || j<0 || j>n-1 ) return 0;
        if(board[i][j]=='M') return 1;
        return 0;
    }
    void dfs(vector<vector<char>>& board,int i,int j)
    {
        int m=board.size(),n=board[0].size();
        if(i<0 || i>m-1 || j<0 || j>n-1 || vis[i][j] ) return ;
        if(board[i][j]=='E')
        {
            vis[i][j]=1;
            int sum=0;
            for(int k=0;k<8;k++)
            {
                sum+=fun(board,i+x[k],j+y[k]);
            }
            if(sum) board[i][j]=sum+'0';
            else 
            {
                board[i][j]='B';
                for(int k=0;k<8;k++)
                {
                    dfs(board,i+x[k],j+y[k]);
                }
            }
        }
    }
    vector<vector<char>> updateBoard(vector<vector<char>>& board, vector<int>& click) {
        int m=board.size(),n=board[0].size();
        vis=vector<vector<int>>(m,vector<int>(n));
        int i=click[0],j=click[1];
        if(board[i][j]=='M')
        {
            board[i][j]='X';
            return board;
        }
        if(board[i][j]=='E')
        {
            dfs(board,i,j);
        }
        return board;
    }
};