1 /*查找并压缩路径*/
 2 int Find_set(int x)
 3 {
 4     int temp = fa[x];
 5     if(x != fa[x])
 6         fa[x] = Find_set(fa[x]);    //路径压缩
 7     return fa[x];
 8 }
 9 /*使用*/
10 p[x] = Find_set(x);

1 void Union(int x,int y)
2 {
3     int fx = Find_set(x);
4     int fy = Find_set(y);
5     if (fx == fy)    //根节点Same
6         return;
7     father[fx] = fy;
8 }

 1 //并查集：D x y 表示x和y分属不同帮派，A x y表示查询x和y的关系
 2 //在并查集的基础上加上relate[]，表示t与其父结点fa[t]的关系
 3 //Memory:948K Time:344Ms
 4 #include<iostream>
 5 #include<cstring>
 6 #include<cstdio>
 7 using namespace std;
 8 #define MAX 100005
 9 int n, m;
10 int fa[MAX], r[MAX];    //father node - relation
11 int find(int x)
12 {
13     if (x != fa[x]) {
14         int pa = fa[x];
15         fa[x] = find(fa[x]);    //路径压缩
16         r[x] ^= r[pa];    //改变关系
17     }
18     return fa[x];
19 }
20 int main()
21 {
22     int T;
23     scanf("%d", &T);
24     while (T--)
25     {
26         scanf("%d%d", &n, &m);
27         memset(r, 0, sizeof(r));
28         for (int i = 0; i <= n;i++)
29             fa[i] = i;
30         while (m--)
31         {
32             int c1, c2;
33             char flag;
34             scanf("\n%c%d%d", &flag, &c1, &c2);
35             //找出根节点
36             int p1 = find(c1), p2 = find(c2);
37             if (flag == 'A')
38             {
39                 if (p1 != p2)
40                     printf("Not sure yet.\n");
41                 else if (r[c1] == r[c2])
42                     printf("In the same gang.\n");
43                 else printf("In different gangs.\n");
44             }
45             else {
46                 fa[p1] = p2;
47                 r[p1] = r[c1] == r[c2];    //c1-p1与c2-p2关系相同则p1与p2关系不同，反之亦然
48             }
49         }
50     }
51     return 0;
52 }