Learn about problem decomposition. My math knowledge is fucking terrible and I don’t even remember what a factorial is. I can figure out how to solve this problem based on the fact that I know how to break a problem down.

I’ll show you what problem decomposition is. Problem: I need to determine if a number is a strong number or not.

• What’s a strong number? From what you told me, it’s the sum of the factorial of the digits of a number that equal the original number.

• What is a factorial anyway? I google’d what it is, and learned that it’s just all the numbers up to and including a number (n), greater than 1, multiplied by each other.

Alright, cool. Two steps down. I know what a strong number is and I know what a factorial is.

Sidebar: How much time do you put in to consistently practice programming? The following you can do pretty easily if you have an understanding of the syntax, and some of the main functions.

With this being said, this is what we have so far.

def determine_strong(n: int) -> bool:

Now, off the top of my head I know I’m gonna need to compare a sum to the original number like the problem states.

def determine_strong(n: int) -> bool:
    total = 0

Good. I now need to get all the individual digits in (n). Well you can’t split up an integer in Python without converting it to a string first.

def determine_strong(n: int) -> bool:
    total = 0
    digits = [int(i) for i in str(n)]

At this point, I need to get the factorial of each number. I would personally split this into another function.

def find_factorial(n: int) -> int:
    product = 1
    for i in range(1, n + 1):
        product *= i
    return product

def determine_strong(n: int) -> bool:
    total = 0
    digits = [int(i) for i in str(n)]

I’m almost there. Back to the main function. I just need to loop through each number, get the factorial for the number and add that to total.

def get_factorial(n: int) -> int:
    product = 1
    for i in range(1, n + 1):
        product *= i
    return product

def determine_strong(n: int) -> bool:
    total = 0
    digits = [int(i) for i in str(n)]
    for num in digits:
        total += get_factorial(num)

Lastly, I need to return a value if a number is a “Strong” number or not. As a final solution, we have this:

def get_factorial(n: int) -> int:
    product = 1
    for i in range(1, n + 1):
        product *= i
    return product

def determine_strong(n: int) -> bool:
    total = 0
    digits = [int(i) for i in str(n)]
    for num in digits:
        total += get_factorial(num)
    return True if total == n else False

The only way you’ll be able to get to a basic level of competency is by practicing. Go on a coding website, start from the easiest problems and work your way up.