n=4的一些解
..3..0....2..0....0..1....1..3....1..1....2..0....1..0....1..1....3..1....3..2
..1..1....0..1....0..0....1..0....1..1....3..1....0..0....3..3....1..2....2..0
..2..2....3..2....1..1....0..1....2..1....1..0....0..3....3..2....0..3....2..3
..2..2....2..0....3..0....0..2....2..3....0..2....1..2....0..1....0..0....0..0
..1..2....3..0....0..3....3..2....0..0....0..3....1..0....2..1....0..0....2..3