Practice #2 I

#include <bits/stdc++.h>
using namespace std;

#define int long long
const int N = 105;
int a[N];

signed main()
{
    int t;
    cin >> t; //test cases
    while(t--){
        int n;
        cin >> n; // array size
        for(int i = 0; i < n; i++){
            cin >> a[i]; //array elements
        }
        sort(a , a + n);
        int k = n / 2 , ans = 0;
        for(int i = 0; i < k; i++){
            ans += (a[n - i - 1] - a[i]);
        }
        cout << ans << endl;
    }
}