poj2236 Wireless Network

#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
struct cell{
bool set;
int x;int y;
}a[1010];
bool vis[1010][1010];
int root[1010];
int n,d;
bool dis(cell a,cell b){
if((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y)<=d*d)
return 1;
else
return 0;
}
int find(int c){
if(c!=root[c])
root[c]=find(root[c]);
return root[c];
}
void check(int a,int b){
int ra=find(a);
int rb=find(b);
root[ra]=rb;
}
int main(){
int i,j;
char ope[5];
int com;
int from,to;
while(scanf("%d%d",&n,&d)!=EOF){
for(i=1;i<=n;i++){
root[i]=i;
a[i].set=0;
}
memset(vis,0,sizeof(vis));
for(i=1;i<=n;i++)
scanf("%d%d",&a[i].x,&a[i].y);
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
vis[i][j]=vis[j][i]=dis(a[i],a[j]);
while(scanf("%s",ope)!=EOF){   //我真的很菜，scanf("%c")不能用在这里
if(ope[0]=='O'){
scanf("%d",&com);
a[com].set=1;
for(i=1;i<=n;i++){
if(i==com) continue;
if(vis[i][com]&&a[i].set)
check(i,com);
}
}
if(ope[0]=='S'){
scanf("%d%d",&from,&to);
if(find(from)==find(to))
printf("SUCCESS\n");
else
printf("FAIL\n");
}
}
}
return 0;
}