HackerEarth Fredo and Sums problem solution

In this HackerEarth Fredo and Sums problem solution, Fredo has an array A consisting of N elements. He wants to divide the array into N/2 pairs where each array element comes in exactly one pair. Say that pair i has elements Xi and Yi, he defines S as :

S = Sigma(i=1,N/2) abs(Xi – Yi)

He asks you to find the minimum and maximum value of S.

#include<bits/stdc++.h>
#define ll long long
using namespace std;
int main()
{
   int t;
   cin>>t;
   assert(t>=1 && t<=10);
   while(t--)
   {
      int n,a[100005];
      cin>>n;
      assert(n>=1 & n<=1e5);
      assert(!(n&1));
      for(int i=0;i<n;i++)
      {
         cin>>a[i];
         assert(a[i]>=-1e9 && a[i]<=1e9);
      }
      sort(a,a+n);
      ll mins=0,maxs=0;
      for(int i=1;i<n;i+=2)
         mins+=(ll)(a[i]-a[i-1]);
      for(int i=0;i<n/2;i++)
         maxs+=(ll)(a[n-1-i]-a[i]);
      cout<<mins<<" "<<maxs<<"n";
   }
   return 0;
}