Question

Code works, but feels very brute force, suggestions?

Goal of the code is to supply an array length, and then as fast as possible generate all possible unique binary combinations with that array length.

CODE:

class Array
  def sequence(i = 0, *a)
    return [a] if i == size
    self[i].map {|x|
      sequence(i+1, *(a + [x]))
    }.inject([]) {|m, x| m + x}
  end
end


[(0..1),(0..1),(0..1)].sequence

OUTPUTS:

[[0, 0, 0], [0, 0, 1], [0, 1, 0], [0, 1, 1], [1, 0, 0], [1, 0, 1], [1, 1, 0], [1, 1, 1]]

Answer 1

permutation and repeated_permutation are built in, so you can do:

def sequence(n)
  [0, 1].repeated_permutation(n).to_a
end
p sequence(3) #=>[[0, 0, 0], [0, 0, 1], [0, 1, 0], [0, 1, 1], [1, 0, 0], [1, 0, 1], [1, 1, 0], [1, 1, 1]]