Inverse Fizzbuzz

inv_fizzbuzz.rb

def fizzbuzz(n)
  str = ""
  str << (n % 3 == 0 ? "fizz" : "")
  str << (n % 5 == 0 ? "buzz" : "")
end

list = ["fizz", "fizz", "buzz"]
arr = (1..100).map { |n| [n, fizzbuzz(n)] }.reject { |h| h.last.empty? }

res = arr.each_slice(list.length).to_a.find_all do |slice|
  slice.map { |s| s.last }.join == list.join
end.sort_by { |slice| slice.size }

if res.empty?
  puts "Invalid"
  exit
else
  res = res.first
end

(res.first.first..res.last.first).each do |n|
  if not res.find { |x| x.first == n }
    res << [n, nil]
  end
end

puts res.sort_by { |slice| slice.first }.inspect