题目链接：

思路很简单，傻逼的我输出写成了FALL，然后遍历的时候for循环写错了，还好很快我就Debug出来了。

#include 
     
      struct Point{    int x,y;} points[1010];int father[1010];bool vis[1010]= {
   false};int Find_Set (int x){    if(x!=father[x])        father[x] = Find_Set(father[x]);    return father[x];}int main(){    int N,d;    scanf("%d%d",&N,&d);    for(int i=1; i<=N; i++)        father[i] = i;    for(int i=1; i<=N; i++)        scanf("%d%d",&points[i].x,&points[i].y);    getchar();    char ch;    while(scanf("%c",&ch)!=EOF)    {        getchar();        int n,m;        if(ch=='O')        {            scanf("%d",&n);            getchar();            vis[n] = true;            for(int i=1; i<=N; i++)            {                if(i!=n&&vis[i])                {                    int tx = points[n].x - points[i].x;                    int ty = points[n].y - points[i].y;                    if(tx*tx+ty*ty<=d*d)                    {                        int fx = Find_Set(i);                        int fy = Find_Set(n);                        if(fx!=fy)                            father[fy] = fx;                    }                }            }        }        else        {            scanf("%d%d",&n,&m);            getchar();            int fx,fy;            fx = Find_Set(n);            fy = Find_Set(m);            if(fx!=fy)                printf("FAIL\n");            else printf("SUCCESS\n");        }    }    return 0;}