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