1837. Sum of Digits in Base K

Problem

Given an integer n (in base 10) and a base k, return **the *sum* of the digits of n after converting n from base 10 to base **k.

After converting, each digit should be interpreted as a base 10 number, and the sum should be returned in base 10.

  Example 1:

Input: n = 34, k = 6
Output: 9
Explanation: 34 (base 10) expressed in base 6 is 54. 5 + 4 = 9.

Example 2:

Input: n = 10, k = 10
Output: 1
Explanation: n is already in base 10. 1 + 0 = 1.

  Constraints:

• 1 <= n <= 100

• 2 <= k <= 10

Solution (Java)

class Solution {
    public int sumBase(int n, int k) {
        String str = Integer.toString(Integer.parseInt(n + "", 10), k);
        int sum = 0;
        for (char c : str.toCharArray()) {
            sum += Character.getNumericValue(c);
        }
        return sum;
    }
}

Explain:

nope.

Complexity:

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