POJ-3714 Raid 平面最近点对

　　题目链接：http://poj.org/problem?id=3714

　　分治算法修改该为两个点集的情况就可以了，加一个标记。。。

 //STATUS:C++_AC_2094MS_4880KB
 #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=1e30;
 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{
     double x,y;
     int id,index;
     Node(){}
     Node(double _x,double _y,int _index):x(_x),y(_y),index(_index){}
 }nod[N],temp[N];

 int n;

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

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

 bool 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);
     double d,d1,d2;
     int i,j,k,mid=(l+r)/;
     pii pn1=Closest_Pair(l,mid);
     pii pn2=Closest_Pair(mid+,r);
     if(pn1.first==pn1.second || nod[pn1.first].index==nod[pn1.second].index)
         d1=OO;
     else d1=dist(nod[pn1.first],nod[pn1.second]);
     if(pn2.first==pn2.second || nod[pn2.first].index==nod[pn2.second].index)
         d2=OO;
     else d2=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(fabs(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 && fabs(temp[j].y-temp[i].y)<d;j++){
             if(dist(temp[i],temp[j])<d && (temp[i].index^temp[j].index)){
                 d=dist(temp[i],temp[j]);
                 ret=make_pair(temp[i].id,temp[j].id);
             }
         }
     }
     return ret;
 }

 void Init()
 {
     int i,t;
     double x,y;
     scanf("%d",&t);
     n=t<<;
     for(i=;i<t;i++){
         scanf("%lf%lf",&x,&y);
         nod[i]=Node(x,y,);
     }
     for(;i<n;i++){
         scanf("%lf%lf",&x,&y);
         nod[i]=Node(x,y,);
     }
     sort(nod,nod+n,cmpxy);
     for(i=;i<n;i++)nod[i].id=i;
 }

 int main(){
  //   freopen("in.txt","r",stdin);
     int T,i,j;
     scanf("%d",&T);
     while(T--)
     {
         Init();
         pii ans=Closest_Pair(,n-);

         printf("%.3lf\n",dist(nod[ans.first],nod[ans.second]));
     }
     return ;
 }