并查集
1 #include<iostream>
2 #include<cstdio>
3 using namespace std;
4
5 int f[50001];//,r[30001];
6 int m,n;
7 void Init()
8 {
9 for(int i=1;i<=m;++i) f[i]=i;
10 //memset(r,0,sizeof(r));
11 }
12
13 int father(int k)
14 {
15 if(k !=f[k])
16 return father(f[k]);
17 return f[k];
18 }
19
20 void unionset(int k,int t)
21 {
22 int i=father(k);
23 int j=father(t);
24 f[j]=i;
25 /*if(r[i]<r[j])
26 f[i]=j;
27 else
28 {
29 f[j]=i;
30 if(r[i]==r[j])
31 r[i]++;
32 }*/
33
34 }
35 void readData()
36 {
37 int i,j,k,t,num;
38 num=1;
39 while(cin>>m>>n)
40 {
41 if(m==0 && n==0) break;
42 Init();//
43 for(int i=1;i<=n;++i)
44 {
45 scanf("%d%d",&k,&t);
46 if(father(k)!=father(t))
47 {
48 unionset(k,t);
49 }
50 }
51 int ans=0;
52 for(i=1;i<=m;++i)
53 {
54 if(i==f[i]) ans++;
55 }
56 printf("Case %d: %d\n",num++,ans);
57 }
58 }
59 int main()
60 {
61 //Init();
62 //freopen("a.txt","r",stdin);
63 readData();
64 return 0;
65 }