Niuke IOI Weekly Tournament 23-Improve Group Stars (Circular Divide Card Problem)

Topic

answer

1. Ring evenly split card problem: Click here for details ,

2. The main idea: we regard it as a one-way transfer, which can be derived from the formula c[i] = s[i-1]-(i-1) * avg; the
   array c is the c of the warehouse location, and the median is the most Excellent solution

Code

#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>

using namespace std;
typedef long long ll;
const int N = 1e6 + 10;

int n;
ll a[N], s[N], c[N];

ll slove() {
    
    

    for (int i = 1; i <= n; i++) s[i] = s[i - 1] + a[i];

    ll avg = s[n] / n;

    c[1] = 0;
    for (int i = 2; i <= n; i++) c[i] = s[i - 1] - (i - 1) * avg;

    sort(c + 1, c + 1 + n);

    ll res = 0;
    for (int i = 1; i <= n; i++) res += abs(c[i] - c[(n + 1) / 2]);

    return res;

}


int main() {
    
    

    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];

    cout << slove() << endl;

    return 0;
}