n=4的一些解
..0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..0....0..1....0..1
..0..1....0..0....0..0....1..0....0..0....0..0....0..0....0..0....1..1....2..2
..0..0....0..0....1..0....1..1....0..1....0..0....0..0....0..1....1..1....2..2
..0..0....0..0....1..1....1..1....0..0....1..1....0..1....1..1....1..1....2..2