Radar Installation 

 1 #include<cstdio>
 2 #include<cstdlib>
 3 #include<cstring>
 4 #include<algorithm>
 5 #include<math.h>
 6 
 7 const  int MAXN=10000;
 8 using namespace std;
 9 struct node
10 {
11     double x1,x2;
12 } p[MAXN];
13 bool cmp(node a,node b)
14 {
15    return a.x2<b.x2;
16 }
17 int main()
18 {
19     int n,m,ii=0;
20     double x,y;
21     while(scanf("%d%d",&n,&m))
22     {
23         ii++;
24         if(n==0&&m==0) break;
25         int flag=0;
26         for(int i=0; i<n; i++)
27         {
28             scanf("%lf%lf",&x,&y);
29             if(fabs(y)>m) flag=1;
30             double c=sqrt(m*m-y*y);
31             p[i].x1=x+c;
32             p[i].x2=x-c;
33         }
34         if(flag==1)
35         {
36             printf("Case %d: %d\n",ii,-1);
37             continue;
38         }
39         sort(p,p+n,cmp);
40         double c=p[0].x1;
41         int t=1;
42         for(int i=1; i<n; i++)
43         {
44             if(p[i].x1<c)
45             {
46                 c=p[i].x1;
47             }
48             else if(p[i].x2>c)
49             {
50                 t++;
51                 c=p[i].x1;
52             }
53         }
54         printf("Case %d: %d\n",ii,t);
55     }
56     return 0;
57 }
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posted @ 2013-08-05 18:39  null1019  阅读(219)  评论(0)    收藏  举报