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#include <stdio.h>
#include <string.h>
#include <math.h>
#define Max 20000
#define eps 1e-5
struct
node
{
double
x,y;
}node[2*Max+10];
int
n,m;
bool
flag;
double
dis(int
i,int j)
{
double
x=node[i].x-node[j].x;
double
y=node[i].y-node[j].y;
return
sqrt(x*x+y*y);
}
bool
check(int
i,int j,int x,int y)
{
if(fabs(dis(i,x)-dis(j,x))>eps)return
false;
if(fabs(dis(i,y)-dis(j,y))>eps)return
false;
return
true;
}
void
reco(int
x,int y)
{
int
i,j;
i=j=x;
while(1)
{
i++;
j--;
if(j==0) j=m;
if(i==y)
{
flag=true;
return
;
}
if(check(i,j,x,y)==false)return
;
}
}
int
main()
{
int
i,j,cou;
scanf("%d",&cou);
for(i=0;i<cou;i++)
{
scanf("%d",&n);
m=2*n;
for(j=1;j<=m;j+=2)
{
scanf("%lf%lf",&node[j].x,&node[j].y);
}
node[m+1]=node[1];
for(j=2;j<=m;j+=2)
{
node[j].x=(node[j-1].x+node[j+1].x)/2;
node[j].y=(node[j-1].y+node[j+1].y)/2;
}
flag=false;
for(j=1;j<=n;j++)
{
reco(j,j+n);
if(flag)break;
}
if(flag)printf("Case %d: YES\n",i+1);
else
printf("Case %d: NO\n",i+1);
}
return
0;
}
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