HDU 1213 How Many Tables (并查集)

 1 # include<cstdio>
 2 # include<iostream>
 3 
 4 using namespace std;
 5 
 6 # define MAX 1004
 7 
 8 int f[MAX];
 9 
10 int getf ( int v )
11 {
12     if ( f[v]==v )
13         return v;
14     else
15     {
16         f[v] = getf(f[v]);
17         return f[v];
18     }
19 }
20 
21 
22 void merge ( int v,int u )
23 {
24     int t1 = getf(v);
25     int t2 = getf(u);
26     if ( t1!=t2 )
27     {
28         f[t2] = t1;
29     }
30 }
31 
32 int main(void)
33 {
34     int t;scanf("%d",&t);
35     while ( t-- )
36     {
37         int n;
38         scanf("%d",&n);
39         for ( int i = 1;i <= n;i++ )
40         {
41             f[i] = i;
42         }
43         int tt;
44         scanf("%d",&tt);
45         for ( int i = 1;i <= tt;i++ )
46         {
47             int a,b;
48             scanf("%d %d",&a,&b);
49             merge(a,b);
50 
51         }
52         int sum = 0;
53         for ( int i = 1;i <= n;i++ )
54         {
55             if ( f[i]==i )
56                 sum++;
57         }
58         printf("%d\n",sum);
59 
60     }
61     return 0;
62 }