表演队 参考代码

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

typedef long long LL;
const int maxn = 100000 + 100;
int n, k;
LL tmp, ans;
LL num[maxn], sum[maxn];

int main() {
#ifdef ExRoc
    freopen("test.txt", "r", stdin);
#endif
    ios::sync_with_stdio(false);

    cin >> n >> k;
    for (int i = 1; i <= n; ++i) {
        cin >> num[i];
    }
    sort(num + 1, num + 1 + n);
    for (int i = 1; i <= n; ++i) {
        sum[i] = sum[i - 1] + num[i];
    }
    for (int i = 2; i <= k; ++i) {
        tmp += (num[i] - num[i - 1]) * (i - 1) * (k - i + 1);
    }

    ans = tmp;
    for (int i = k + 1; i <= n; ++i) {
        tmp -= sum[i - 1] - sum[i - k];
        tmp += num[i - k] * (k - 1);
        tmp -= sum[i - 1] - sum[i - k];
        tmp += num[i] * (k - 1);
        ans = min(ans, tmp);
    }
    cout << ans << endl;

    return 0;
}