hdu_1213

 1 #include<iostream>
 2 #include<cstdio>
 3 #define MAXN 1111
 4 int TestCase = 0;
 5 int N,M;
 6 int tr[MAXN];
 7 int tr_find(int x)
 8 {
 9     while(tr[x] != x)
10         x = tr[x];
11     return x;
12 }
13 void tr_merge(int a,int b)
14 {
15     int ra = tr_find(a);
16     int rb = tr_find(b);
17     if(ra!=rb)
18         tr[ra] = rb;
19     return;
20 }
21 int main()
22 {
23 //    freopen("in.txt","r",stdin);
24     scanf("%d",&TestCase);
25     while(TestCase --) {
26         scanf("%d%d",&N,&M);
27         for(int i = 1; i <= N; i++)
28             tr[i] = i;
29         while(M--) {
30             int a,b;
31             scanf("%d%d",&a,&b);
32             tr_merge(a,b);
33         }
34         int s = 0;
35         for(int i = 1; i <= N; i++)
36 //            std::cout<<" "<<tr[i];
37             if(tr[i] == i)
38                 ++s;
39         printf("%d\n",s);
40     }
41 }