POJ2236--Wireless Network(并查集)

#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
int coor[10005][10005];
int par[1005];
int rank[1005];
void init(int n){
    for(int i=1;i<=n;i++){
        par[i]=i;
        rank[i]=0;
    }
}
int find(int d){
    if(par[d]==d)
        return d;
    else
        return par[d]=find(par[d]);
}
void unite(int a,int b){
    int x=find(a);
    int y=find(b);
    if(x==y)return;
    if(rank[x]<rank[y])
        par[x]=y;
    else{
        par[y]=x;
        if(rank[x]==rank[y])rank[x]++;
    }
}
bool same(int x,int y){
    return find(x)==find(y);
}
int main(){
    int n,d;
    cin>>n>>d;
    d=d*d;
    init(n);
    vector<pair<int,int> > coordinate(n+1);
    for(int i=1;i<=n;i++){
        int x,y;
        cin>>x>>y;
        coordinate[i]=(make_pair(x,y));
    }
    char c;
    vector<int> repaired;
    while(cin>>c){
        if(c=='S'){
            int a,b;
            cin>>a>>b;
            if(same(a,b))
                cout<<"SUCCESS"<<endl;
            else
                cout<<"FAIL"<<endl;
        }
        else{
            int a;
            cin>>a;
            int x=coordinate[a].first;
            int y=coordinate[a].second;
            repaired.push_back(a);
            for(int i=0;i<repaired.size();i++){
                if(repaired[i]!=a){
                    int xi=coordinate[repaired[i]].first;
                    int yi=coordinate[repaired[i]].second;
                    if((x-xi)*(x-xi)+(y-yi)*(y-yi)<=d){
                        unite(repaired[i],a);
                    }
                }
            }
        }
    }
    return 0;
} 

　　http://poj.org/problem?id=2236