Difference Between Element Sum and Digit Sum of an Array Python/Java solution

In Python or Java, iterate through the array, accumulate the element sum, and extract digits using modulo and division inside a loop. The logic is identical across languages because it relies only on basic arithmetic operations and simple iteration.

What is the best approach for Difference Between Element Sum and Digit Sum of an Array?

The standard approach iterates through the array and extracts digits using modulo operations. For each number, add the full value to the element sum and repeatedly use num % 10 and num / 10 to accumulate the digit sum. This runs in O(n * d) time where d is the number of digits per element and uses O(1) extra space.

Is Difference Between Element Sum and Digit Sum of an Array asked at Google/Amazon/Meta?

Problems involving digit extraction and arithmetic manipulation appear frequently in coding interviews at large tech companies. While this exact problem is relatively simple, similar number-processing questions are common screening exercises used by companies like Amazon and Google.

What data structure is used in Difference Between Element Sum and Digit Sum of an Array?

The primary data structure is a simple array traversal. The algorithm does not require additional structures like hash maps or stacks. It relies mainly on arithmetic operations such as modulo and integer division.

What is the time complexity of Difference Between Element Sum and Digit Sum of an Array?

The time complexity is O(n * d). The algorithm iterates through n numbers in the array, and for each number processes its digits individually. Since integers have a limited number of digits, this behaves close to O(n) in practice.

2535. Difference Between Element Sum and Digit Sum of an Array - Practice Online

Q: Is Difference Between Element Sum and Digit Sum of an Array easy or hard?

This problem is classified as Easy. It mainly tests understanding of array traversal and digit extraction using modulo arithmetic. Most solutions are short and run in O(n) time with constant space.

Q: How to solve Difference Between Element Sum and Digit Sum of an Array in O(n)?

Traverse the array once while maintaining two running totals: element sum and digit sum. Extract digits from each number using modulo (num % 10) and division (num /= 10). After processing all elements, return the absolute difference between the two sums. This effectively runs in linear time with constant space.

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