John Salerno wrote:
> ::sigh:: Well, I'm stuck again and it has to do with my get_factors
> function again, I think. Even with the slight optimization, it's
> taking forever on 20! (factorial, not excitement) :) It's frustrating
> because I have the Python right, but I'm getting stuck on the math.
>
> The problem:
>
> "What is the smallest positive number that is evenly divisible by all
> of the numbers from 1 to 20?"
>
>
>
> Here's the function (it's in the problem3.py file, hence the import
> below):
>
> import math
>
> def get_factors(number):
> factors = []
>
> for n in range(2, int(math.sqrt(number))):
> if number % n == 0:
> factors.append(n)
> factors.append(number // n)
>
> return factors
>
> And here's my new script for the new exercise:
>
> import math
> from problem3 import get_factors
>
> max_num = 20
> n = math.factorial(max_num)
> factors = get_factors(n)
> div_all = []
>
> for x in factors:
> for y in range(2, max_num+1):
> if x % y != 0:
> break
> elif y == max_num:
> div_all.append(x)
>
> print(min(div_all))
>
> It could easily be that I'm simply approaching it all wrong. I just
> thought that maybe using the factorial of the highest number in the
> range (in this case, 20) would be an easy way of finding which numbers
> to test.
These are almost "trick questions" in a way, because of the math behind
them. If the question were "What is the tallest high-school student in
Scranton, PA?" then searching a population for the property would be the
only way to go. BUT you can also build up the answer knowing the
factorization of all the numbers up to 20.
Mel.
--
http://mail.python.org/mailman/listinfo/python-list
