[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 = ;

 LL n, a[N+], m;

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