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Stored size: 569 Bytes
Contents
# coding: utf-8
class Integer
def semiperfect?
return false if deficient?
return true if perfect?
possibles = { 0 => true}
proper_sod = (sod = σ || 0) - self
proper_divisors.reverse.each do |divisor|
possibles.keys.each do |possible|
possibles.delete(possible) if possible + sod < self
x = possible + divisor
return true if x == self or x == proper_sod
possibles[x] = true if x < self
end
sod -= divisor
end
false
end
alias :pseudoperfect? :semiperfect?
end
Version data entries
15 entries across 15 versions & 1 rubygems