Difference between element sum and digit sum of an array

Array Math

85.3% acceptance

Feb 25, 2026

811

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|.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn difference_of_sum(nums: Vec<i32>) -> i32 {
    let elem_sum: i32 = nums.iter().sum();
    let digit_sum: i32 = nums
      .iter()
      .map(|&x| {
        let mut s = 0;
        let mut n = x;
        while n > 0 {
          s += n % 10;
          n /= 10;
        }
        s
      })
      .sum();
    (elem_sum - digit_sum).abs()
  }
}