[HAOI 2008]糖果传递

Description

有n个小朋友坐成一圈，每人有ai个糖果。每人只能给左右两人传递糖果。每人每次传递一个糖果代价为1。

Input

第一行一个正整数nn<=1'000'000，表示小朋友的个数．

接下来n行，每行一个整数ai，表示第i个小朋友得到的糖果的颗数．

Output

求使所有人获得均等糖果的最小代价。

Sample Input

4
1
2
5
4

Sample Output

4

题解

咳咳...[UVa 11300]Spreading the Wealth

//It is made by Awson on 2017.10.23
#include <set>
#include <map>
#include <cmath>
#include <ctime>
#include <cmath>
#include <stack>
#include <queue>
#include <vector>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
#define LL long long
#define Min(a, b) ((a) < (b) ? (a) : (b))
#define Max(a, b) ((a) > (b) ? (a) : (b))
#define sqr(x) ((x)*(x))
#define Abs(a) ((a) < 0 ? (-(a)) : (a)) 
using namespace std;
const int N = 1000000;

LL n, a[N+5], m;

void work() {
  scanf("%lld", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%lld", &a[i]); m += a[i];
  }
  m /= n;
  for (int i = 1; i <= n; i++) {
    a[i] = a[i-1]+a[i]-m;
  }
  sort(a+1, a+n+1);
  LL mid = a[n>>1], ans = 0;
  for (int i = 1; i <= n; i++) ans += Abs(mid-a[i]);
  printf("%lld
", ans);
}
int main() {
  work();
  return 0;
}