[LeetCode] 728. Self Dividing Numbers_Easy tag: Math

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.

 

思路就是一次判断, 然后用一个helper function去判断是否为self-divisible的数即可.

Code

class Solution(object):
    def selfDividingNumbers(self, left, right):
        ## Solution, basic  T:O(n lg(right))   , but we know max(right) = 10000, then T: O(n) 
        def helper(n):
            for c in str(n):
                if c == '0' or n%int(c):
                    return False
            return True
        ans = []
        for i in range(left, right + 1):
            if helper(i):
                ans.append(i)
        return ans