学步园

#include<algorithm>  
#include<iostream>  
#include<cstring>  
#include<cstdio>  
#define inf 0x7fffffff  
#define MAXN 100001
using namespace std;

inline int read() {
    int x = 0, f = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9') {
        if (ch == '-')f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9') {
        x = x * 10 + ch - '0';
        ch = getchar();
    }
    return x*f;
}
int n, a[10001], s[10001];
long long ans;

int main() {
    n = read();
    for (int i = 1; i <= n; i++)
        a[i] = read();
    sort(a + 1, a + n + 1);
    for (int i = 1; i < n; i++)
        s[i] = a[i + 1] - a[i];
    for (int i = 1; i < n; i++)
        ans += (long long) i * (n - i) * s[i];
    printf("%lld", 2 * ans);
    return 0;
}