POJ2236(并查集)

#include <iostream>  
#include <string.h>  
#include <stdio.h>  
  
using namespace std;  
const int N = 1005;  
  
struct Point  
{  
    int x,y;  
};  
  
Point p[N];  
int repaired[N];  
int pre[N],rank[N];  
  
int dist(Point A,Point B)  
{  
    return (A.x-B.x)*(A.x-B.x)+(A.y-B.y)*(A.y-B.y);  
}  
  
void Init(int n)  
{  
    for(int i=1;i<=n;i++)  
    {  
        pre[i] = i;  
        rank[i] = 1;  
    }  
}  
  
int Find(int x)  
{  
    if(pre[x] != x)  
        pre[x] = Find(pre[x]);  
    return pre[x];  
}  
  
void Union(int x,int y)  
{  
    x = Find(x);  
    y = Find(y);  
    if(x == y) return;  
    if(rank[x] >= rank[y])  
    {  
        pre[y] = x;  
        rank[x] += rank[y];  
    }  
    else  
    {  
        pre[x] = y;  
        rank[y] += rank[x];  
    }  
}  
  
int main()  
{  
    char ch[5];  
    int n,d,x,y;  
    scanf("%d%d",&n,&d);  
    for(int i=1;i<=n;i++)  
        scanf("%d%d",&p[i].x,&p[i].y);  
    int cnt = 0;  
    Init(n);  
    while(~scanf("%s",ch))  
    {  
        if(ch[0] == 'O')  
        {  
            scanf("%d",&x);  
            for(int i=0;i<cnt;i++)  
            {  
                if(dist(p[repaired[i]],p[x]) <= d*d)  
                    Union(repaired[i],x);  
            }  
            repaired[cnt++] = x;  
        }  
        else  
        {  
            scanf("%d%d",&x,&y);  
            x = Find(x);  
            y = Find(y);  
            if(x == y) puts("SUCCESS");  
            else       puts("FAIL");  
        }  
    }  
    return 0;  
}