Count the Digits That Divide a Number — LeetCode 2520 Python Solution

The problem

Given an integer num, return the number of digits in num that divide num. An integer val divides nums if nums % val == 0.

Example

Input

num = 7

Output

1

Explanation

7 divides itself, hence the answer is 1.

Python solution

class Solution:
    def countDigits(self, num: int) -> int:
        ans, x = 0, num
        while x:
            x, val = divmod(x, 10)
            ans += num % val == 0
        return ans

Complexity

Pattern: Math and Number Theory

Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 2520. Count the Digits That Divide a Number is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Math.

The math and number theory guide has the Python template for the pattern and the 485 LeetCode problems that use it.

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