POJ 1703 Find them, Catch them （并查集）

Find them, Catch them

Time Limit: 1000MS		Memory Limit: 10000K
Total Submissions: 33685		Accepted: 10399

Description

The police office in Tadu City decides to say ends to the chaos, as launch actions to root up the TWO gangs in the city, Gang Dragon and Gang Snake. However, the police first needs to identify which gang a criminal belongs to. The present question is, given two criminals; do they belong to a same clan? You must give your judgment based on incomplete information. (Since the gangsters are always acting secretly.) 

Assume N (N <= 10^5) criminals are currently in Tadu City, numbered from 1 to N. And of course, at least one of them belongs to Gang Dragon, and the same for Gang Snake. You will be given M (M <= 10^5) messages in sequence, which are in the following two kinds: 

1. D [a] [b] 
where [a] and [b] are the numbers of two criminals, and they belong to different gangs. 

2. A [a] [b] 
where [a] and [b] are the numbers of two criminals. This requires you to decide whether a and b belong to a same gang. 

Input

The first line of the input contains a single integer T (1 <= T <= 20), the number of test cases. Then T cases follow. Each test case begins with a line with two integers N and M, followed by M lines each containing one message as described above.

Output

For each message "A [a] [b]" in each case, your program should give the judgment based on the information got before. The answers might be one of "In the same gang.", "In different gangs." and "Not sure yet."

Sample Input

1
5 5
A 1 2
D 1 2
A 1 2
D 2 4
A 1 4

Sample Output

Not sure yet.
In different gangs.
In the same gang.

类似于 食物链的 《挑战》作法  不同的时候 合并下 有两种可能都要合并

判断不同的话 一个就够了(因为之前已经都合并了)~ 那么剩下的就是not sure了

AC代码如下：

//
//  POJ 1703 Find them, Catch them
//
//  Created by TaoSama on 2015-03-16
//  Copyright (c) 2015 TaoSama. All rights reserved.
//
#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <string>
#include <set>
#include <vector>
#define CLR(x,y) memset(x, y, sizeof(x))

using namespace std;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const int N = 1e5 + 10;

int par[2 * N], rank[2 * N];
void init(int n) {
	for(int i = 1; i <= n; ++i) {
		par[i] = i;
		rank[i] = 0;
	}
}

int find(int x) {
	if(par[x] == x) return x;
	return par[x] = find(par[x]);
}

void unite(int x, int y) {
	x = find(x); y = find(y);
	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() {
#ifdef LOCAL
	freopen("in.txt", "r", stdin);
//	freopen("out.txt","w",stdout);
#endif
	ios_base::sync_with_stdio(0);

	int t; scanf("%d", &t);
	while(t--) {
		int n, m; scanf("%d%d", &n, &m);
		init(2 * n);
		for(int i = 1; i <= m; ++i) {
			char op[2]; int x, y;
			scanf("%s%d%d", op, &x, &y);
			if(op[0] == 'A') {
				if(same(x, y))
					printf("In the same gang.\n");
				else if(same(x, y + n))
					printf("In different gangs.\n");
				else
					printf("Not sure yet.\n");
			} else {
				unite(x + n, y);
				unite(x, y + n);
			}
		}
	}
	return 0;
}