距离之和

#pragma GCC optimize(1)
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
#define rep(i,j,k) for(register int i=(j);i<=(k);++i)
using namespace std;
long long n, a[100001];
long long ans = 0; 
template<class T> inline void read(T &x) {
    x=0;
    register char c=getchar();
    register bool f=0;
    while(!isdigit(c))f^=c==‘-‘,c=getchar();
    while(isdigit(c))x=x*10+c-‘0‘,c=getchar();
    if(f)x=-x;
}
int main() {
    read(n);
    rep(i, 1, n) {
        read(a[i]);
    }
    sort(a + 1, a + 1 + n);
    for (register int i = 1; i < n; i ++) {
        ans += (n - i) * (a[i + 1] - a[i]);
    }
    long long cur = ans;
    for (int i = 2; i <= n; i ++) {
        cur += (a[i] - a[i - 1]) * (i - 1 - (n - i + 1));
        ans = ans + cur;
    }
    cout << ans << endl;
    return 0;
}