2520. Count the Digits That Divide a Number

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 1:

Input: num = 7
Output: 1
Explanation: 7 divides itself, hence the answer is 1.

Example 2:

Input: num = 121
Output: 2
Explanation: 121 is divisible by 1, but not 2. Since 1 occurs twice as a digit, we return 2.

Example 3:

Input: num = 1248
Output: 4
Explanation: 1248 is divisible by all of its digits, hence the answer is 4.

  Constraints:

• 1 <= num <= 109

• num does not contain 0 as one of its digits.

Solution (Java)

class Solution {
    public int countDigits(int num) {
        int answer = 0;
        int n = num;
        while(n>0){
            if(num % (n%10) == 0) answer++;
            n/=10;
        }
        return answer;
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).