NQueens nQueens = new NQueens();
nQueens.setId(0L);
nQueens.setN(n);
List<Column> columnList = new ArrayList<Column>(n);
for (int i = 0; i < n; i++) {
Column column = new Column();
column.setId((long) i);
column.setIndex(i);
columnList.add(column);
}
nQueens.setColumnList(columnList);
List<Row> rowList = new ArrayList<Row>(n);
for (int i = 0; i < n; i++) {