UVa-1595 - Symmetry

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<cmath>
 5 using namespace std;
 6 const int maxx=1010;
 7 const double eps=1e-5;
 8 int main()
 9 {
10     //freopen("in.txt","r",stdin);
11     //freopen("out.txt","w",stdout);
12     int T;
13     scanf("%d",&T);
14     while(T--)
15     {
16         int n;
17         scanf("%d",&n);
18         int x[maxx]={},y[maxx]={};
19         double xx=0;
20         for(int i=1;i<=n;i++)
21         {
22             scanf("%d%d",&x[i],&y[i]);
23             xx+=x[i];
24         }
25         xx/=n;
26         int i,j;
27         for(i=1;i<=n;i++)
28         {
29             for(j=1;j<=n;j++)
30             {
31                 if(abs(2*xx-x[i]-x[j])<eps&&abs(y[i]-y[j])<eps)
32                     break;
33             }
34             if(j>n) break;
35         }
36         puts(i>n?"YES":"NO");
37     }
38 }