Class SodokuBoard {
    static class BoardCellIndex {
        public int row;
        public int col;
        public BoardCellIndex(int row, int col){
            this.row = row;
            this.col = col;
        }
    }

    Map<BoardCellIndex, List<Integer>> board;

    public SodokuBoard(){
        board = new HashMap<BoardCellIndex, List<Integer>>();
        tmpIndex = new BoardCellIndex(0,0);

        // init board
        for(int row = 0; row < 9 ; ++row){
            for( int col = 0; col < 9 ; ++col){
                BoardCellIndex index = new BoardCellIndex(row, col);
                board.put(index, new ArrayList<Integer>);
            }
        }
    }

    // don't create new object for access of Map
    BoardCellIndex tmpIndex;

    /**
    * Ezen keresztul elered az adott cellahoz tartozo List<int>-et
    * ami a jelölteket tartalmazza, es hozza tudsz adni vagy el tudsz venni
    * jelolteket
    * pl.
    * myboard.getCandidates(1,2).add(9);
    * myboard.getCandidates(1.3).remove(1);
    */
    public List<int> getCandidates(int row, int col){
        tmpIndex.row = row;
        tmpIndex.col = col;
        return board.get(tmpIndex);
    }

}