Count the Digits That Divide a Number

Problem Description

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

Key Insights

• We need to iterate through each digit of the number num.
• For each digit, we check if it divides num without leaving a remainder.
• Count the digits that satisfy the division condition.
• The input number is guaranteed to be between 1 and 1,000,000,000 and will not contain the digit '0'.

Space and Time Complexity

Time Complexity: O(d), where d is the number of digits in num (at most 10 digits).
Space Complexity: O(1), since we are using a constant amount of space.

Solution

To solve the problem, we will use a simple algorithm that involves:

1. Converting the integer num to a string to easily iterate through each digit.
2. For each digit, convert it back to an integer and check if it divides num using the modulus operator.
3. Maintain a count of how many digits divide num and return this count at the end.

Code Solutions