题目链接

#include<iostream>
#include<cstdio>
#include<cstring>
#include<vector>
#include<cmath>
using namespace std;

const int maxn=1010;

struct node
{
    int x,y;
}N[maxn];

int pre[maxn];
vector<int> V;
int find(int x)
{
    int r=x;
    while(r!=pre[r]){
        r=pre[r];
    }
    int i=x,j;
    while(i!=r){
        j=pre[i];
        pre[i]=r;
        i=j;
    }
    return r;
}
void join(int x,int y)
{
    int fx=find(x),fy=find(y);
    if(fx!=fy)
        pre[fx]=fy;
}

int main()
{
    int n;
    double d;
    cin>>n>>d;
    for(int i=1;i<=n;i++)
        cin>>N[i].x>>N[i].y;
    for(int i=1;i<=n;i++)
        pre[i]=i;
    char ch;
    int x1,x2;
    while(cin>>ch){
        if(ch=='O'){
            cin>>x1;
            int len=V.size();
            for(int i=0;i<len;i++){
                double distance=sqrt((N[V[i]].y-N[x1].y)*(N[V[i]].y-N[x1].y)+(N[V[i]].x-N[x1].x)*(N[V[i]].x-N[x1].x));
                if(distance<=d){
                    join(V[i],x1);
                    /*
                    for(int i=1;i<=n;i++){
                        printf("%d ",pre[i]);
                    }
                    printf("\n");
                    */
                }
            }
            V.push_back(x1);
        }
        else {
            cin>>x1>>x2;
            if(find(x1)==find(x2)){
                cout<<"SUCCESS"<<endl;
            }
            else {
                cout<<"FAIL"<<endl;
            }
        }
    }
    return 0;
}