并查集

 1 #include <iostream>
 2 #include <cstdio>
 3 using namespace std;
 4 int fa[10003];
 5 int n , m;
 6 int getf(int p)
 7 {
 8     if(fa[p] == p)
 9         return p;
10     return fa[p] = getf(fa[p]);
11 }
12 int merge(int x , int y)
13 {
14     int t1 = getf(x) , t2 = getf(y);
15     if(t1 == t2)
16         return 0;
17     fa[t1] = t2;
18     return 1;
19 }
20 int main()
21 {
22     int opt , x , y;
23     scanf("%d%d" , &n , &m);
24     for(int i = 1; i <= n; i++)
25         fa[i] = i;
26     for(int i = 1; i <= m; i++)
27     {
28         scanf("%d%d%d" , &opt , &x , &y);
29         if(opt == 1)
30             merge(x , y);
31         if(opt == 2)
32         {
33             if(getf(x) == getf(y))
34                 printf("Y\n");
35             else
36                 printf("N\n");
37         }
38     }
39     return 0;
40 }

 

来源：https://www.cnblogs.com/leo-xy/p/11385911.html