smlpth daily 2022-11-26

2022-11-26.rb

def efficient_part2(input)
  n = input.length
  r = Array.new(n, 1)
  p_up, p_down = 1, 1
  0.upto(n - 1) do |i|
    j = n - i - 1
    r[i] *= p_up
    r[j] *= p_down
    p_up *= input[i]
    p_down *= input[j]
  end
  r
end

Potentiellement plus simple à comprendre, c'est la même chose sinon :

def efficient_part2(input)
  n = input.length
  r = Array.new(n, 1)
  p_up = 1
  0.upto(n - 1) do |i|
    r[i] *= p_up
    p_up *= input[i]
  end
  p_down = 1
  (n - 1).downto(0) do |j|
    r[j] *= p_down
    p_down *= input[j]
  end
  r
end