n=7的一些解决方案:
..5...-5...-6...-2....2....3....1....5...-6...-3...-3....1....4...-2...-1...-1
.-1...-2...-3....3...-2...-2...-5...-1....0...-3....0....7...-3...-4...-5...-3
..2....2....4....2...-1...-5....1....1...-4....2...-1....2....2...-4...-2...-7
..1...-2....0....0....4....1....3...-1...-1....1....6...-4....6....2...-2...-1