17 lines
576 B
Scala
17 lines
576 B
Scala
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case class Pos(row: Int, column: Int) {
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def sameRow(p: Pos) = row == p.row
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def sameColumn(p: Pos) = column == p.column
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def sameDiag(p: Pos) = (p.column - column).abs == (p.row - row).abs
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def illegal(p: Pos) = sameRow(p) || sameColumn(p) || sameDiag(p)
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def legal(p: Pos) = !illegal(p)
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}
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def rowSet(size: Int, row: Int) = Iterator.tabulate(size)(column => Pos(row, column))
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def expand(solutions: Iterator[List[Pos]], size: Int, row: Int) =
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for {
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solution <- solutions
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pos <- rowSet(size, row)
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if solution forall (_ legal pos)
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} yield pos :: solution
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