hdoj Cow Sorting

题意：给你n个无序的数，通过相邻的两个数交换，交换的价值是两个数之和，求使之increasing order的最小代价和

与poj3270不同的是poj可以每个数任意交换，可以用置换群来做

#include<cstdio>
#include<cstring>
#include<vector>
#include<iostream>
#include<algorithm>
using namespace std;
#define ll __int64
#define N 100000+10
ll a[N],c[N],s[N],Sum[N];
int n;
ll lowbit(ll x)
{
        return x&(-x);
}
void updata(ll t,ll value)
{
        for(int i=t;i<=n;i+=lowbit(i))
        {
                c[i]+=value;
                s[i]+=t;
        }
}
int getSum(ll x,ll &y)
{
        y=0;
        ll temp=0;
        for(int i=x;i>=1;i-=lowbit(i))
        {
                temp+=c[i];
                y+=s[i];
        }
       return temp;
}
int main()
{

   while(scanf("%d",&n)!=EOF)
   {
           ll sum=0;
           Sum[0]=0;
           for(ll i=1;i<=n;i++)
                   {
                           scanf("%I64d",&a[i]);
                           Sum[i]=Sum[i-1];
                           Sum[i]+=a[i];
                   }

           for(ll i=1;i<=n;i++)
           {

                   updata(a[i],1);
                   ll y;
                   ll temp=i-getSum(a[i],y);
                   sum+=temp*a[i]+Sum[i]-y;

           }
           printf("%I64d\n",sum);
   }
   return 0;
}