POJ 1703

带关系的并查集，每次都存自己和父节点的关系即可。0表示相同，1表示不同

#include <iostream>
#include <stdio.h>

using namespace std;

#define MMAX 100050

int p[MMAX];
int rank[MMAX];

void init() {
	for(int i = 0; i < MMAX; i++) {
		p[i] = i;
		rank[i] = 0;
	}
}

int find(int x) {
	if(p[x] == x) return x;
	else {
		int k = p[x];
		p[x] = find(p[x]);
		rank[x] = (rank[x]+rank[k])%2;
	}
	return p[x];
}

int unionSet(int a, int b) {
	int t1 = find(a);
	int t2 = find(b);
	if(t1 == t2) {
		if(rank[a] == rank[b]) return 1;
		return 0;
	}
	p[t2] = t1;
	rank[t2] = (rank[a] - rank[b] + 1)%2;
	return 0;
}

int main() {
	int t;
	int n, m;
	scanf("%d", &t);
	while(t--) {
		init();
		scanf("%d%d", &n, &m);
		for(int i = 0; i < m; i++) {
			int a, b;
			char cmd[3];
			scanf("%s%d%d", cmd, &a, &b);
			if('D' == cmd[0]) {
				unionSet(a, b);
			}
			else {
				int t1 = find(a);
				int t2 = find(b);
				if(t1 != t2) printf("Not sure yet.\n");
				else if(t1 == t2 && rank[a] == rank[b]) printf("In the same gang.\n");
				else printf("In different gangs.\n");
			}
		}
	}
	return 0;
}