Submission #3786360

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Source Code Expand

A, B = input().split()
base = [0] * 20
for i in range(1, 20):
  base[i] = 2 * 10 ** (i - 1) + 8 * base[i - 1]
def forbidden(N):
  cnt = 0
  for i, n in enumerate(N):
    n = int(n)
    if n < 4:
      cnt += base[len(N) - i - 1] * n
    elif n == 4:
      cnt += base[len(N) - i - 1] * 4 + (int(N[i + 1:]) if i < len(N) - 1 else 0) + 1
      break
    elif n < 9:
      cnt += base[len(N) - i - 1] * (n - 1) + 10 ** (len(N) - i - 1)
    elif n == 9:
      cnt += base[len(N) - i - 1] * 8 + 10 ** (len(N) - i - 1) + (int(N[i + 1:]) if i < len(N) - 1 else 0) + 1
      break
  return cnt
print(forbidden(B) - forbidden(A) + (1 if '4' in A or '9' in A else 0))

Submission Info

Judge Result