n=4的一些解决方案:
..2..2..0....2..2..1....2..1..1....1..0..1....2..1..0....2..2..2....0..2..1
..1..1..1....1..1..0....1..2..2....1..2..1....0..1..0....0..0..0....2..0..1
..0..0..0....0..2..1....1..2..2....0..1..2....0..1..2....0..0..0....1..1..0
..1..1..1....1..1..2....1..2..2....2..1..2....0..1..0....1..1..1....1..1..0
..2..0..0....1..1..0....1..2..2....2..1..0....1..0..1....2..2..2....2..0..1