UVA 11300 Spreading the Wealth 中位数 *

题目地址：http://vjudge.net/problem/UVA-11300

思路来自刘汝佳的书，不得不说太厉害了

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int maxn=1000001+2;
#define abs(a) ((a)>0?(a):-(a));
LL C[maxn],A[maxn];
int main(int argc, char const *argv[])
{
	int n;
	while(scanf("%d",&n)==1)
	{
		LL tot=0;
		for(int i=1;i<=n;i++)
			scanf("%lld",&A[i]),
			tot+=A[i];

		LL M=tot/n;
		C[0]=0;
		for(int i=1;i<n;i++)
			C[i]=C[i-1]+A[i]-M;
		sort(C,C+n);
		
		LL x1=C[n/2],ans=0;
		for(int i=0;i<n;i++)
			ans+=abs(x1-C[i]);
		printf("%lld\n",ans);
	}
	return 0;
}