并查集 POJ 1703 Find them, Catch them

/************************************************
* Author        :Running_Time
* Created Time  :2015/9/9 星期三 15:17:58
* File Name     :O.cpp
 ************************************************/

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <bitset>
#include <cstdlib>
#include <ctime>
using namespace std;

#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
typedef long long ll;
const int N = 2e5 + 10;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
struct UF   {
    int rt[N], rk[N];
    void init(void) {
        memset (rt, -1, sizeof (rt));
        memset (rk, 0, sizeof (rk));
    }
    int Find(int x) {
        return rt[x] == -1 ? x : rt[x] = Find (rt[x]);
    }
    void Union(int x, int y)    {
        x = Find (x), y = Find (y);
        if (x == y) return ;
        if (rk[x] > rk[y])  {
            rt[y] = x;  rk[x] += rk[y] + 1;
        }
        else    {
            rt[x] = y;  rk[y] += rk[x] + 1;
        }
    }
    bool same(int x, int y) {
        return Find (x) == Find (y);
    }
}uf;

int main(void)    {
    int T;  scanf ("%d", &T);
    while (T--) {
        int n, m;  scanf ("%d%d", &n, &m);
        uf.init ();
        char s[3];
        for (int x, y, i=1; i<=m; ++i)   {
            scanf ("%s %d %d", &s, &x, &y);
            if (s[0] == ‘D‘)    {
                uf.Union (x, y + n);
                uf.Union (x + n, y);
            }
            else if (s[0] == ‘A‘)   {
                if (uf.same (x, y)) puts ("In the same gang.");
                else if (uf.same (x, y + n))    puts ("In different gangs.");
                else    puts ("Not sure yet.");
            }
        } 
    }

    return 0;
}