hdu 4312 Meeting point-2

http://acm.hdu.edu.cn/showproblem.php?pid=4312

和 4311 的区别在于一个转换 自己还真想不出来

max(|x|,|y|) 等于 max(|x-y|,|x+y|)/2

原来的两点 (x1,y1)   (x2,y2)  转换为   (x1-y1,x1+y1)  (x2-y2,x2+y2) 

最后记得除以2

#include<iostream>

#include<cstdio>

#include<algorithm>

#include<cstring>

#include<cmath>

#include<map>

#include<queue>

#include<cmath>

#define LL long long



using namespace std;

const int N=100005;



struct node

{

    int I;

    LL x,y;

}mem[N];

LL l[N];

LL sumx[N];

LL sumy[N];

bool cmp1(node a,node b)

{

    return a.x<b.x;

}

bool cmp2(node a,node b)

{

    return a.y<b.y;

}

int main()

{

   int T;

   scanf("%d",&T);

   while(T--)

   {

       int n;

       scanf("%d",&n);

       for(int i=1;i<=n;++i)

       {

           LL x,y;

           cin>>x>>y;

           mem[i].x=x-y;

           mem[i].y=x+y;

           mem[i].I=i;

       }

       sort(mem+1,mem+n+1,cmp1);

       l[0]=0;

       for(int i=1;i<=n;++i)

       {

           l[i]=l[i-1]+mem[i].x;

       }

       for(int i=1;i<=n;++i)

       {

           sumx[mem[i].I]=((i-1)*mem[i].x-l[i-1])+((l[n]-l[i])-(n-i)*mem[i].x);

       }

       sort(mem+1,mem+n+1,cmp2);

       l[0]=0;

       for(int i=1;i<=n;++i)

       {

           l[i]=l[i-1]+mem[i].y;

       }

       for(int i=1;i<=n;++i)

       {

           sumy[mem[i].I]=((i-1)*mem[i].y-l[i-1])+((l[n]-l[i])-(n-i)*mem[i].y);

       }

       LL ans=sumx[1]+sumy[1];

       for(int i=2;i<=n;++i)

       {

           if(sumx[i]+sumy[i]<ans)

           ans=sumx[i]+sumy[i];

       }

       cout<<(ans/2)<<endl;

   }

   return 0;

}