public List<String[]> select(int m) {
		final List<String[]> result = new ArrayList<>((int) count(this.datas.length, m));
		select(0, new String[m], 0, result);
		return result;
	}
@Test
	public void selectTest() {
		Combination combination = new Combination(new String[] { "1", "2", "3", "4", "5" });
		List<String[]> list = combination.select(2);
		assertEquals(Combination.count(5, 2), list.size());

		assertArrayEquals(new String[] {"1", "2"}, list.get(0));
		assertArrayEquals(new String[] {"1", "3"}, list.get(1));
		assertArrayEquals(new String[] {"1", "4"}, list.get(2));
		assertArrayEquals(new String[] {"1", "5"}, list.get(3));
		assertArrayEquals(new String[] {"2", "3"}, list.get(4));
		assertArrayEquals(new String[] {"2", "4"}, list.get(5));
		assertArrayEquals(new String[] {"2", "5"}, list.get(6));
		assertArrayEquals(new String[] {"3", "4"}, list.get(7));
		assertArrayEquals(new String[] {"3", "5"}, list.get(8));
		assertArrayEquals(new String[] {"4", "5"}, list.get(9));

		List<String[]> selectAll = combination.selectAll();
		assertEquals(Combination.countAll(5), selectAll.size());

		List<String[]> list2 = combination.select(0);
		assertEquals(1, list2.size());
	}