#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int Mod=1e9+7;
const ll INF = 10000000000000;
const int N = 1e6+7;
 
    void solve() {
       int n;
       cin >> n;
       vector<int> a(n);
       for(int i=0;i<n;i++) cin >> a[i];
       sort(a.begin(),a.end());
       ll score = 0;
       int mi=a[0],ma=a[n-1];
       for(int i=1;i<n;i++){
            score+=ma-mi;
       } 
       cout << score << '\n';
    }
int main(){ 
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
 
    int t;
    cin >> t;
    while (t--) solve();
 
    return 0;
}
 

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

MwoxCjY5CjMKNyA2IDUKNQoxIDEgMSAyIDIK

3
1
69
3
7 6 5
5
1 1 1 2 2