Submission #1498866

---

Source Code Expand

# 8進数を使う解法(解説参照)
A, B = gets.split.map(&:to_i)
def oct_down(n)
  s = n.to_s
  if (i = (s =~ /[49]/))
    s[i] = (s[i] == "4" ? "3" : "8")
    fill = s.length - i - 1
    s[i+1, fill] = "8" * fill
  end
  return s.tr("0123456789", "0123_4567_").to_i(8)
end

oa, ob = oct_down(A), oct_down(B)
oa += 1 if A.to_s =~ /[49]/

p(B-A+1 - (ob-oa+1))

Submission Info

Judge Result