728. Self Dividing Numbers
A self-dividing number is a number that is divisible by every digit it contains.
For example, 128 is a self-dividing number because 128 % 1 == 0, 128 % 2 == 0, and 128 % 8 == 0.
Also, a self-dividing number is not allowed to contain the digit zero.
Given a lower and upper number bound, output a list of every possible self dividing number, including the bounds if possible.
Example 1:
Input:
left = 1, right = 22
Output: [1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 15, 22]
Note:
The boundaries of each input argument are 1 <= left <= right <= 10000.
Solution
class Solution:
def selfDividingNumbers(self, left: int, right: int) -> List[int]:
result = []
for i in range(left, right + 1):
if self.isSelfDividing(i):
result.append(i)
return result
def isSelfDividing(self, n):
original_num = n
while n > 0:
digit = n % 10
if digit == 0 or original_num % digit != 0:
return False
n //= 10
return True
This solution is longer than most, because I created a helper method to check if a number was self-dividing. Basically, we iterate over each digit of the number by doing basic math. We can return the last digit of a number by doing number % 10, and we can truncate the last digit of a number by doing number / 10.
We use these properties to go through the given list of numbers and check if each one is a self dividing number.