pub fn solve(input: &String) {
    let all_numbers = input.split_whitespace()
                           .filter(|str| !str.is_empty())
                           .map(|str| str.parse::<i32>().unwrap())
                           .collect::<Vec<_>>();

    let mut left = Vec::new();
    let mut right = Vec::new();

    for idx in (0..all_numbers.len()).step_by(2) {
        left.push(all_numbers[idx]);
        right.push(all_numbers[idx + 1]);
    }

    left.sort();
    right.sort();

    let mut sum_of_distances = 0;

    for idx in 0..left.len() {
        sum_of_distances += (left[idx] - right[idx]).abs();
    }

    println!("sum of distances: {}", sum_of_distances);
}