POJ3714+最近点对

特判标记即可

 1 #include<stdio.h>
 2 #include<string.h>
 3 #include<stdlib.h>
 4 #include<math.h>
 5 #include<algorithm>
 6 using namespace std;
 7 const double eps = 1e-8;
 8 const double inf = 9999999999.0;
 9 const int maxn =  100005;
10 struct Point{
11     double x,y;
12     int flag;
13 };
14 Point pnt[ maxn<<1 ],temp[ maxn<<1 ];
15 double dis( Point a,Point b ){
16     return sqrt( (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y) );
17 }
18 int cmpxy( Point a,Point b ){
19     if( a.x!=b.x )
20         return a.x<b.x;
21     else
22         return a.y<b.y;
23 }
24 int cmpx( Point a,Point b ){
25     return a.x<b.x;
26 }
27 int cmpy( Point a,Point b ){
28     return a.y<b.y;
29 }
30 double solve( int L,int R ){
31     if( L==R )
32         return inf;
33     if( L+1==R ){
34         if( pnt[L].flag==pnt[R].flag )
35             return inf;
36         else
37             return dis( pnt[L],pnt[R] );
38     }
39     int mid = (L+R)/2;
40     double res,Ldis,Rdis;
41     Ldis = solve( L,mid );
42     Rdis = solve( mid+1,R );
43     res = min( Ldis,Rdis );
44     int cnt = 0;
45     for( int i=L;i<=R;i++ ){
46         if( fabs(pnt[i].x-pnt[mid].x)<=res ){
47             temp[cnt++] = pnt[i];
48         }
49     }
50     sort( temp,temp+cnt,cmpy );
51     for( int i=0;i<cnt;i++ ){
52         for( int j=i+1;j<cnt;j++ ){
53             if( fabs( pnt[i].y-pnt[j].y )>res ) break;
54             if( pnt[i].flag==pnt[j].flag ) continue;
55             res = min( res,dis(pnt[i],pnt[j]) );
56         }
57     }
58     return res;
59 }
60 
61 int main(){
62     int ca;
63     scanf("%d",&ca);
64     while( ca-- ){
65         int n;
66         scanf("%d",&n);
67         for( int i=0;i<n;i++ ){
68             scanf("%lf%lf",&pnt[i].x,&pnt[i].y);
69             pnt[i].flag = 1;
70         }
71         for( int i=n;i<2*n;i++ ){
72             scanf("%lf%lf",&pnt[i].x,&pnt[i].y);
73             pnt[i].flag = 2;
74         }
75         sort( pnt,pnt+2*n,cmpxy );
76         double Ans = solve( 0,2*n-1 );
77         printf("%.3lf\n",Ans);
78     }
79     return 0;
80 }
View Code

 

posted @ 2013-07-26 22:31  xxx0624  阅读(310)  评论(0)  编辑  收藏  举报