Rotated Digits Count

Problem

Count how many numbers from 1 through n become a different valid number when each digit is rotated 180 degrees.

Digits 0, 1 and 8 stay valid and unchanged, 2, 5, 6 and 9 stay valid but change, and 3, 4 and 7 make the number invalid. A number counts only if it is valid and at least one digit changes.

Hint

A number containing any of 3, 4 or 7 can never be rotated at all.

Test cases

case 1

in: [10]

expected: 4

case 2

in: [1]

expected: 0

case 3

in: [2]

expected: 1

case 4

in: [20]

expected: 9

case 5

in: [100]

expected: 40

Starter codePython

def rotated_digits_count(n):
    # Your code here
    pass

5 test cases · run your code against them in the editor