module Combinatorics::Derange
Public Class Methods
D(n)
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Wrapper for derangement cardinality method defined above
@note The letter `D' is academic representation for derangements
# File lib/combinatorics/derange/cardinality.rb, line 19 def self.D(n) cardinality(n) end
cardinality(n)
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Compute the number of derangements for a data structure of given size
@see Math.subfactorial
# File lib/combinatorics/derange/cardinality.rb, line 10 def self.cardinality(n) Math.subfactorial(n) end