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

#define int long long  

void solve() {
	int n, d;
	cin >> n >> d;

	vector<int> a(n + 1);
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	sort(a.begin(), a.end());

	int sum = 0;
	for (int i = 1; i <= n; i++) {
		sum += a[i];
	}

	if (d == 1) {
		cout << sum * (sum - 1) / 2 << "\n";
	} else if (d == 2) {
		int ans = sum * (sum - 1) / 2;
		for (int i = 1; i <= n; i++) {
			ans -= a[i] * (a[i] - 1) / 2;
		}
		cout << ans << "\n";
	} else {
		int ans = 0;
		for (int i = 1; i <= n; i++) {
			ans += a[i] * (n - i);
		}
		cout << ans << "\n";
	}
}

signed main() {  
    ios::sync_with_stdio(false);
    cin.tie(nullptr);  

    int t;
    cin >> t;
    while (t--) {
    	solve();
    }

    return 0;
}