9 lines
281 B
Scala
9 lines
281 B
Scala
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def combs[A](n: Int, l: List[A]): Iterator[List[A]] = n match {
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case _ if n < 0 || l.lengthCompare(n) < 0 => Iterator.empty
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case 0 => Iterator(List.empty)
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case n => l.tails.flatMap({
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case Nil => Nil
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case x :: xs => combs(n - 1, xs).map(x :: _)
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})
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}
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