2535. Difference Between Element Sum and Digit Sum of an Array

Problem

You are given a positive integer array nums.

• The element sum is the sum of all the elements in nums.

• The digit sum is the sum of all the digits (not necessarily distinct) that appear in nums.

Return **the *absolute* difference between the element sum and digit sum of **nums.

Note that the absolute difference between two integers x and y is defined as |x - y|.

  Example 1:

Input: nums = [1,15,6,3]
Output: 9
Explanation: 
The element sum of nums is 1 + 15 + 6 + 3 = 25.
The digit sum of nums is 1 + 1 + 5 + 6 + 3 = 16.
The absolute difference between the element sum and digit sum is |25 - 16| = 9.

Example 2:

Input: nums = [1,2,3,4]
Output: 0
Explanation:
The element sum of nums is 1 + 2 + 3 + 4 = 10.
The digit sum of nums is 1 + 2 + 3 + 4 = 10.
The absolute difference between the element sum and digit sum is |10 - 10| = 0.

  Constraints:

• 1 <= nums.length <= 2000

• 1 <= nums[i] <= 2000

Solution (Java)

class Solution {
    public int differenceOfSum(int[] nums) {
       int elementSum = 0;
        int digitSum = 0;
        for (int num : nums) {
            elementSum += num;
            String numString = Integer.toString(num);
            for (int i = 0; i < numString.length(); i++) {
                digitSum += numString.charAt(i) - '0';
            }
        }
        return Math.abs(elementSum - digitSum);   
    }
}

Explain:

nope.

Complexity:

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