int m = 0,n=0;    void solve(vector
     
      
       > &board) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        if(board.empty()||board[0].empty())            return;        m = board.size();        n = board[0].size();                int i,j;        for(j=0;j
       
        >& board)    {        if(i>=m||i<0||j<0||j>=n||board[i][j]!='O')            return;        board[i][j] = '+';        dfs(i-1,j,board);        dfs(i+1,j,board);        dfs(i,j-1,board);        dfs(i,j+1,board);    }