poj2231

简单题

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
using namespace std;

#define maxn 10006

int f[maxn];

int main()
{
    //freopen("t.txt", "r", stdin);
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++)
        scanf("%d", &f[i]);
    sort(f, f + n);
    long long ans = 0, sum = 0;
    for (int i = 1; i < n; i++)
    {
        sum += ((long long)(f[i] - f[i - 1])) * i;
        ans += sum;
    }
    printf("%lld\n", ans * 2);
    return 0;
}