bzoj 3170: [Tjoi 2013]松鼠聚会

#include<cstdio>
#include<iostream>
#include<algorithm>
#define M 100008
using namespace std;
struct data
{
    int x,y,num;
}a[M];
long long n,suma[M],suma1[M],ans,sumb[M],sumb1[M];
bool cmpx(data a1,data a2)
{
    return a1.x<a2.x;
}
bool cmpy(data a1,data a2)
{
    return a1.y<a2.y;
}
int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
      {
        int a1,a2;
        scanf("%d%d",&a1,&a2);
        a[i].x=a1+a2;
        a[i].y=a1-a2;
      }
    sort(a+1,a+n+1,cmpx);
    ans=100000000000000000LL;
    for(int i=1;i<=n;i++)
      {
        suma[i]=suma[i-1]+a[i].x;
        a[i].num=i;
      }
    for(int i=n;i;i--)
      suma1[i]=suma1[i+1]+a[i].x;
    sort(a+1,a+n+1,cmpy);
    for(int i=1;i<=n;i++)
      sumb[i]=sumb[i-1]+a[i].y;
    for(int i=n;i;i--)
      sumb1[i]=sumb1[i+1]+a[i].y;
    for(int i=1;i<=n;i++)
      {
        long long ss=0,x=suma[a[i].num]-suma[a[i].num-1],y=sumb[i]-sumb[i-1];
        ss=x*(a[i].num-1)-suma[a[i].num-1]+suma1[a[i].num+1]-x*(n-a[i].num)+y*(i-1)-sumb[i-1]+sumb1[i+1]-y*(n-i);
        ans=min(ss,ans);
      }
    printf("%lld
",ans/2);
    return 0;
}

这个题让我学会了切比雪夫距离。