swustojCalculate Sum-Of-Absolute-Differences(0237)

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include<stack>
#include<iostream>
#include<string.h>
#include<math.h>
using namespace std;int main()
{int n;int a[20005];while (cin >> n){int sum = 0;for (int i = 0; i < n; i++){scanf("%d", &a[i]);}sort(a, a + n);for (int i = 0; i < n-1; i++){sum += abs(a[i] - a[i + 1])*(n - 1 - i)*(i + 1);}cout << sum << endl;}return 0;
}