hdu 5563 Clarke and five-pointed star (枚举)

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 #include<cstdlib>
 6 #include<cmath>
 7 #include<vector>
 8 #include<queue>
 9 #include<map>
10 #include<set>
11 #define eps 10e-6
12 
13 using namespace std;
14 
15 double x[8],y[8];
16 bool vis[8];
17 int order[6];
18 double dis[12];
19 
20 double cal(int i,int j)
21 {
22     return (x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]);
23 }
24 
25 bool isok()
26 {
27     for(int i=0;i<4;i++)
28         dis[i] = cal(order[i+1],order[i+2]);
29     dis[4] = cal(order[5],order[1]);
30     int flag1 = 1;
31     for(int i=0;i<4;i++)
32     {
33         if(fabs(dis[i]-dis[4])>eps)
34         {
35             flag1 = 0;
36             break;
37         }
38     }
39 
40     dis[5] = cal(order[1],order[3]);
41     dis[6] = cal(order[1],order[4]);
42     dis[7] = cal(order[2],order[4]);
43     dis[8] = cal(order[2],order[5]);
44     dis[9] = cal(order[3],order[5]);
45     int flag2 = 1;
46     for(int i=5;i<9;i++)
47     {
48         if(fabs(dis[i]-dis[9])>eps)
49         {
50             flag2 = 0;
51             break;
52         }
53     }
54     return flag1 && flag2;
55 }
56 
57 bool dfs(int pos)
58 {
59     if(pos == 6)
60     {
61         if(isok())
62             return true;
63     }
64     for(int i=0;i<5;i++)
65     {
66         if(!vis[i])
67         {
68             order[pos] = i;
69             vis[i] = true;
70             if(dfs(pos+1)) return true;
71             vis[i] = false;
72         }
73     }
74     return false;
75 }
76 
77 int main()
78 {
79     int T;
80     scanf("%d",&T);
81     while(T--)
82     {
83         memset(vis,0,sizeof(vis));
84         for(int i=0;i<5;i++)
85             scanf("%lf%lf",&x[i],&y[i]);
86         if(dfs(1)) puts("Yes");
87         else puts("No");
88     }
89     return 0;
90 }