HDU-4631 Sad Love Story 平面最近点对

　　题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4631

　　数据是随机的，没有极端数据，所以可以分段考虑，最小值是一个单调不增的函数，然后每次分治算平面最近点对就可以了。。。

 //STATUS:G++_AC_10390MS_23804KB
 #include <functional>
 #include <algorithm>
 #include <iostream>
 //#include <ext/rope>
 #include <fstream>
 #include <sstream>
 #include <iomanip>
 #include <numeric>
 #include <cstring>
 #include <cassert>
 #include <cstdio>
 #include <string>
 #include <vector>
 #include <bitset>
 #include <queue>
 #include <stack>
 #include <cmath>
 #include <ctime>
 #include <list>
 #include <set>
 #include <map>
 using namespace std;
 //#pragma comment(linker,"/STACK:102400000,102400000")
 //using namespace __gnu_cxx;
 //define
 #define pii pair<int,int>
 #define mem(a,b) memset(a,b,sizeof(a))
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 #define PI acos(-1.0)
 //typedef
 typedef __int64 LL;
 typedef unsigned __int64 ULL;
 //const
 const int N=;
 const int INF=0x3f3f3f3f;
 const int MOD=,STA=;
 const LL LNF=1LL<<;
 const double EPS=1e-;
 const double OO=1e15;
 const int dx[]={-,,,};
 const int dy[]={,,,-};
 const int day[]={,,,,,,,,,,,,};
 //Daily Use ...
 inline int sign(double x){return (x>EPS)-(x<-EPS);}
 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}
 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}
 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}
 template<class T> inline T Min(T a,T b){return a<b?a:b;}
 template<class T> inline T Max(T a,T b){return a>b?a:b;}
 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}
 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}
 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}
 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}
 //End

 struct Node{
     LL x,y;
     LL id,index;
     Node(){}
     Node(LL _x,LL _y,LL _index):x(_x),y(_y),index(_index){}
 }p[N],nod[N],temp[N];

 int n;

 LL dist(Node &a,Node &b)
 {
     return (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);
 }

 int cmpxy(Node a,Node b)
 {
     return a.x!=b.x?a.x<b.x:a.y<b.y;
 }

 int cmpy(Node a,Node b)
 {
     return a.y<b.y;
 }

 pii Closest_Pair(int l,int r)
 {
     if(l==r || l+==r)return pii(l,r);
     LL d,d1,d2;
     int i,j,k,mid=(l+r)/;
     pii pn1=Closest_Pair(l,mid);
     pii pn2=Closest_Pair(mid+,r);
     d1=(pn1.first==pn1.second?LNF:dist(nod[pn1.first],nod[pn1.second]));
     d2=(pn2.first==pn2.second?LNF:dist(nod[pn2.first],nod[pn2.second]));
     pii ret;
     d=Min(d1,d2);
     ret=d1<d2?pn1:pn2;
     for(i=l,k=;i<=r;i++){
         if((nod[mid].x-nod[i].x)*(nod[mid].x-nod[i].x)<=d){
             temp[k++]=nod[i];
         }
     }
     sort(temp,temp+k,cmpy);
     for(i=;i<k;i++){
         for(j=i+;j<k && (temp[j].y-temp[i].y)*(temp[j].y-temp[i].y)<d;j++){
             if(dist(temp[i],temp[j])<d){
                 d=dist(temp[i],temp[j]);
                 ret=make_pair(temp[i].id,temp[j].id);
             }
         }
     }

     return ret;
 }

 void Init()
 {
     int i;
     LL x,y,Ax,Bx,Cx,Ay,By,Cy;
     cin>>n>>Ax>>Bx>>Cx>>Ay>>By>>Cy;
     x=y=;
     for(i=;i<n;i++){
         x=(x*Ax+Bx)%Cx;
         y=(y*Ay+By)%Cy;
         p[i]=Node(x,y,i);
     }
 }

 int main(){
  //   freopen("in.txt","r",stdin);
     int T,i,j,k;
     LL ans,hig;
     scanf("%d",&T);
     while(T--)
     {
         Init();

         int end=n;
         pii t;
         ans=;
         while(end>){
             for(i=;i<end;i++)nod[i]=p[i];
             sort(nod,nod+end,cmpxy);
             for(i=;i<end;i++)nod[i].id=i;
             t=Closest_Pair(,end-);
             hig=Max(nod[t.first].index,nod[t.second].index);
             ans+=(end-hig)*dist(nod[t.first],nod[t.second]);
             end=hig;
         }
         cout<<ans<<endl;
     }
     return ;
 }