compare_triplets.rb

def compare_triplets(a, b)
  a.zip(b).map { |left, right| left <=> right }.then do |rounds|
    [rounds.count(1), rounds.count(-1)]
  end
end

compare_triplets([10, 2, 8], [8, 3, 8])
#=> [1, 1]

compare_triplets_again.rb

def compare_triplets(a, b)
  player_a = 0
  player_b = 0

  a.zip(b) do |left, right|
    player_a += 1 if left > right
    player_b += 1 if right > left
  end

  [player_a, player_b]
end

compare_triplets([10, 2, 8], [8, 3, 8])
#=> [1, 1]