BZOJ 1679: [Usaco2005 Jan]Moo Volume 牛的呼声

#include<cstdio>
#include<cstring>
#include<algorithm>
#define g getchar()
#define ll long long
#define inf 0x3f3f3f3f
using namespace std;
inline ll read(){
ll x=0,f=1;char ch=g;
for(;ch<'0'||ch>'9';ch=g)if(ch=='-')f=-1;
for(;ch>='0'&&ch<='9';ch=g)x=x*10+ch-'0';
return x*f;
}
inline void out(ll x){
int a[25],wei=0;
if(x<0)putchar('-'),x=-x;
for(;x;x/=10)a[++wei]=x%10;
if(wei==0){puts("0");return;}
for(int j=wei;j>=1;--j)putchar('0'+a[j]);
putchar('\n');
}
ll a[10005],ans,n;
int main(){
//  freopen("","r",stdin);
//  freopen("","w",stdout);
n=read();
for(int i=1;i<=n;++i)a[i]=read();
sort(a+1,a+1+n);
for(int i=1;i<=n;++i)ans+=a[i]*(i-(n-i+1));
out(ans*2);
return 0;
}