private void toggleCellHint(int row, int col, int hint) {
Cell cell = board.getCell(row, col);
// not allow to toggle hint when cell is holding value
if (cell.isEmpty() == false) {
return;
}
boolean isAdding = !board.getCell(row, col).getHints().contains(hint);
Step step = isAdding ? board.addCellHint(row, col, hint) : board.subCellHint(row, col, hint);
steps.push(step);
boardView.getCellView(row, col).toggleHint(hint, isAdding);
}
