A - Great Graphs

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whiteawll 2022-08-16 14:49:36 博主文章分类：练习题目 ©著作权

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// Problem: A. Great Graphs
// Contest: Codeforces - Codeforces Round #728 (Div. 1)
// URL: https://codeforces.com/problemset/problem/1540/A
// Memory Limit: 256 MB
// Time Limit: 2000 ms
// 2022-02-19 17:17:24
// 
// Powered by CP Editor (https://cpeditor.org)

#include<bits/stdc++.h>
using namespace std;

#define rep(i,l,r) for(int i=(l);i<=(r);i++)
#define per(i,l,r) for(int i=(l);i>=(r);i--)
#define ll long long
#define pii pair<int, int>
#define mset(s,t) memset(s,t,sizeof(t))
#define mcpy(s,t) memcpy(s,t,sizeof(t))
#define fir first
#define pb push_back
#define sec second
#define sortall(x) sort((x).begin(),(x).end())
inline int read () {
    int x = 0, f = 0;
    char ch = getchar();
    while (!isdigit(ch)) f |= (ch=='-'),ch= getchar();
    while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
    return f?-x:x;
}
template<typename T> void print(T x) {
    if (x < 0) putchar('-'), x = -x;
    if (x >= 10) print(x/10);
    putchar(x % 10 + '0');
}
int n;
ll d[100005], a[100005];
void solve() {
    cin >> n;
    memset(d, 0, sizeof d);
    for (int i = 1;  i<= n; i++)
    {
        cin >> d[i];
    }
    sort(d + 1, d+ 1 + n);
    ll ans = 0;
    for (int i = 2;  i<= n; i ++)
        ans += d[i] - d[i - 1];
    ll x = 0, y = n - 1;//第一个数的贡献
    
    for (int i = 1; i <= n; i ++) {
        ans += -d[i] *x + d[i] * y;
        x ++, y --;
    }
    
    cout << ans << endl;
}
int main () {
    int t;
    cin >> t;
    while (t --) solve();
    return 0;
}