This problem can be found on Leetcode.
Given an integer number
n, return the difference between the product of its digits and the sum of its digits.
# assert subtract_product_and_sum(35) == 27
- Product of digits = 3 * 5 = 35
- Sum of digits = 3 + 5 = 8
- Difference = 35 - 8 = 27
# assert subtract_product_and_sum(235) == 20
- Product of digits = 2 3 5 = 30
- Sum of digits = 2 + 3 + 5 = 10
- Difference = 30 - 10 = 20
# define function to with argument for num # cast num to a string to be able to iterate over its digits # assign variable to hold product of digits as 1 # assign variable to hold sum of digits as 0 # iterate over each digit in string version of number: # cast string digit to an integer # product of digits = product of digits * integer digit # sum of digits = sum of digits * integer digit # assign variable difference to be product of digits minus sum of digits # return difference
My solution above is the simplest possible solution. I wouldn't dwell on space and time complexity here. There's minimal space used as only 3 variables are created (no data structures). For time complexity, the simplest possible operation is done which is a single iteration over each digit in the input integer.
def subtract_product_and_sum(n) str_n = str(n) product_of_digits = 1 sum_of_digits = 0 for number in str_n: int_n = int(number) product_of_digits *= int_n sum_of_digits += int_n diff = product_of_digits - sum_of_digits return diff
assert subtract_product_and_sum(35) == 27
assert subtract_product_and_sum(235) == 20