Send Boxes to Alice

E. Send Boxes to Alice

代码：

// Created by CAD on 2019/11/23.
#include <bits/stdc++.h>
#define INF 0x7fffffffffffffff
#define ll long long
using namespace std;

const int maxn=1e6+5;
ll a[maxn];
ll best=INF,n;
void Try(ll k)
{
    ll temp=0;
    for(int i=1;i<n;++i)
        temp+=min(a[i]%k,k-a[i]%k);
//    tst(k,temp);
    best=min(best,temp);
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n;
    for(int i=1;i<=n;++i)
        cin>>a[i],a[i]+=a[i-1];
    for(ll j=2;j*j<=a[n];++j)
        if(a[n]%j==0)
        {
            Try(j);
            while(a[n]%j==0)
                a[n]/=j;
        }
    if(a[n]!=1) Try(a[n]);
    cout<<(best==INF?-1:best)<<endl;
    return 0;
}