POJ 2236并查集

#include"stdio.h"
#include"iostream"
#include"map"
#include"set"
using namespace std;
const int maxn=1050;
double d;
int pre[maxn];
struct point{
double x,y;
}a[maxn];
void init(int n)
{
for(int i=1;i<=n;i++)
pre[i]=i;
}
int Find(int x)
{
return pre[x]==x?x:pre[x]=Find(pre[x]);
}
void join(int x,int y)
{
int xx=Find(x),yy=Find(y);
if(xx!=yy)
pre[xx]=yy;
}
double sqr(double x)
{
return x*x;
}
double dis(point x,point y)
{
return sqr(x.x-y.x)+sqr(x.y-y.y);
}
bool same(int x,int y)
{
return Find(x)==Find(y);
}
bool in(point a,point b)
{
return dis(a,b)<=d*d;
}
int main()
{
int n;

scanf("%d%lf",&n,&d);

map<int,int>Map;
init(n);
for(int i=1;i<=n;i++)
scanf("%lf%lf",&a[i].x,&a[i].y);
char s[2];
while(scanf("%s",s)!=EOF)
{
if(s[0]=='O')
{
int y1;
scanf("%d",&y1);
for(int i=1;i<=n;i++)
{
if(Map[i]>0&&in(a[y1],a[i]))  //电脑修好了,在范围之内
join(y1,i);
}
Map[y1]++;
}
else
{
int y1,y2;
scanf("%d%d",&y1,&y2);
//cout<<Map[y1]<<" "<<Map[y2]<<endl;
if(Map[y1]>0&&Map[y2]>0&&same(y1,y2))  //两台电脑都是有用的 并且 在同一个连通分量中
puts("SUCCESS");
else
puts("FAIL");
}
}

return 0;
}