fn max_min(k: i32, arr: &[i32]) -> i32 {
    //Time complexity: O(n*log(n))
    //Space complexity (ignoring input): O(n)
    let mut arr = arr.to_vec();
    let k = k as usize;
    arr.sort_unstable();
    let mut minimun_unfairness = arr[k - 1] - arr[0];
    for index in 1..(arr.len() - k + 1) {
        if minimun_unfairness > arr[k - 1 + index] - arr[index] {
            minimun_unfairness = arr[k - 1 + index] - arr[index];
        };
    }
    minimun_unfairness
}