BZOJ 1045 糖果传递

奇怪的式子。最后发现取中位数。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#define maxn 1000500
using namespace std;
long long n,a[maxn],c[maxn],x1,sum[maxn],ans=,ave;
int main()
{
    scanf("%lld",&n);
    for (long long i=;i<=n;i++)
    {
        scanf("%lld",&a[i]);
        sum[i]=sum[i-]+a[i];
    }
    ave=sum[n]/n;
    for (long long i=;i<=n;i++) c[i]=(i-)*ave-(sum[i]-sum[]);
    sort(c+,c+n+);
    x1=c[n/+];
    for (long long i=;i<=n;i++) ans+=abs(x1-c[i]);
    printf("%lld\n",ans);
    return ;
}