n=4的一些解决方案:
..1..2..3..1..2....1..0..1..2..1....3..2..0..1..2....1..0..1..0..1
..2..3..1..2..0....0..1..0..1..2....2..0..1..3..0....2..1..2..1..0
..1..2..3..0..2....1..2..1..2..3....3..1..2..0..1....1..2..0..2..1
..0..1..2..3..0....3..0..3..0..2....0..2..3..2..3....0..1..2..3..2
..3..0..1..2..3....0..1..0..3..0....1..0..2..3..0....2..0..1..2..0
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