POJ 2236 Wireless Network (并查集)

#include <iostream>
#include <cstdio>
#include <string>
#include <queue>
#include <vector>
#include <map>
#include <algorithm>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <cmath>
#include <ctime>
using    namespace    std;

const    int    SIZE = 1005;
int        FATHER[SIZE],RANK[SIZE];
int        N,D;
pair<int,int>    G[SIZE];
vector<int>    OK;
double        DIS[SIZE][SIZE];

void    ini(int);
int    find_father(int);
void    unite(int,int);
bool    same(int,int);
double    dis(pair<int,int>,pair<int,int>);
int    main(void)
{
    int    x,y;
    char    ch;

    while(scanf("%d%d",&N,&D) != EOF)
    {
        ini(N);
        for(int i = 1;i <= N;i ++)
            scanf("%d%d",&G[i].first,&G[i].second);
        for(int i = 1;i <= N;i ++)
            for(int j = 1;j <= N;j ++)
                DIS[i][j] = dis(G[i],G[j]);

        while(scanf(" %c",&ch) != EOF)
            if(ch == ‘O‘)
            {
                scanf("%d",&x);
                for(int i = 0;i < OK.size();i ++)
                    if(DIS[x][OK[i]] <= D)
                        unite(x,OK[i]);
                OK.push_back(x);
            }
            else
            {
                scanf("%d%d",&x,&y);
                printf("%s\n",same(x,y) ? "SUCCESS" : "FAIL");
            }
    }

    return    0;
}

void    ini(int n)
{
    for(int i = 1;i <= n;i ++)
    {
        FATHER[i] = i;
        RANK[i] = 0;
    }
}

int    find_father(int n)
{
    if(FATHER[n] == n)
        return    n;
    return    FATHER[n] = find_father(FATHER[n]);
}

void    unite(int x,int y)
{
    x = find_father(x);
    y = find_father(y);

    if(x == y)
        return    ;
    if(RANK[x] < RANK[y])
        FATHER[x] = y;
    else
    {
        FATHER[y] = x;
        if(RANK[x] == RANK[y])
            RANK[y] ++;
    }
}

bool    same(int x,int y)
{
    return    find_father(x) == find_father(y);
}

double    dis(pair<int,int> a,pair<int,int> b)
{
    return    sqrt(pow(a.first - b.first,2) + pow(a.second - b.second,2));
}