count_seven.py

import math

def count_seven(n):
    c = 0
    for i in range(n+1):
        c += str(i).count("7")
    return c

def count_seven_digit_num(num):
    digit_num = len(str(num)) - 1
    top = int(num / math.pow(10, digit_num))
    mod = int(num % math.pow(10, digit_num))

    cnt = top * digit_num * math.pow(10, digit_num - 1)
    if top > 7:
        cnt += math.pow(10, digit_num)
    elif top == 7:
        cnt += num - 7 * math.pow(10, digit_num) + 1
    
    if mod <= 0:
        return int(cnt)
    
    return int(cnt + count_seven_digit_num(mod))

n = [99, 77777, 23678947, 732465890, 1912478368]
for i in n:
  print(count_seven_digit_num(i))
  #print()
  #print(count_seven(i))