采纳哈佛导师f's

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

typedef long long ll;

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

int n;
cin >> n;
vector<ll> a(n);
ll sum = 0;
for (int i = 0; i < n; ++i) {
    cin >> a[i];
    sum += a[i];
}
ll avg = sum / n;

vector<ll> c(n);
c[0] = a[0] - avg;
for (int i = 1; i < n; ++i) {
    c[i] = c[i-1] + a[i] - avg;
}

sort(c.begin(), c.end());
ll mid = c[n / 2];

ll res = 0;
for (ll num : c) {
    res += abs(num - mid);
}

cout << res << endl;

return 0;

}