combinatorial-0.1.0.1: Count, enumerate, rank and unrank combinatorial objects
Combinatorics.Permutation.WithoutSomeFixpoints
enumerate :: Eq a => Int -> [a] -> [[a]] Source #
enumerate n xs list all permutations of xs where the first n elements do not keep their position (i.e. are no fixpoints).
enumerate n xs
xs
n
This is a generalization of derangement.
Naive but comprehensible implementation.
numbers :: Num a => [[a]] Source #
http://oeis.org/A047920