AcWing 913. 排队打水

#include <iostream>
#include <algorithm>
using namespace std;
typedef long long LL;
const int N = 100010;
int n;
int t[N];
int main()
{
    scanf("%d", &n);
    for (int i = 0; i < n; i ++ ) scanf("%d", &t[i]);
    sort(t, t + n);
    reverse(t, t + n);
    LL res = 0;
    for (int i = 0; i < n; i ++ ) res += t[i] * i;
    printf("%lld\n", res);
    return 0;
}