flight_movies.rb

def find_movies(flight_length, movie_lengths)
  movie_complements = Set.new
  movie_lengths.each do |movie_length|
    # We have a good movie pair if this length is the complement of a previous movie's length
    return true if movie_complements.include? movie_length

    # Otherwise, track the complement of this movie's length for checking against succeeding movie lengths
    movie_complements << (flight_length - movie_length)
  end
  
  # We didn't find any movie pairs
  return false
end