hdu 1213 How Many Tables

http://acm.hdu.edu.cn/showproblem.php?pid=1213

 1 #include <cstdio>

 2 #include <cstring>

 3 #include <algorithm>

 4 #define maxn 2000

 5 using namespace std;

 6 

 7 int f[maxn],n,m;

 8 

 9 void inti()

10 {

11     for(int i=1; i<=n; i++)

12     {

13         f[i]=i;

14     }

15 }

16 

17 int find1(int x)

18 {

19     if(x==f[x]) return x;

20     return f[x]=find1(f[x]);

21 }

22 

23 void union2(int a,int b)

24 {

25     int fa=find1(a);

26     int fb=find1(b);

27     if(fa!=fb)

28     {

29         f[fa]=fb;

30     }

31 }

32 

33 int main()

34 {

35     int t;

36     scanf("%d",&t);

37     while(t--)

38     {

39         scanf("%d%d",&n,&m);

40         inti();

41         for(int i=1; i<=m; i++)

42         {

43             int a1,b1;

44             scanf("%d%d",&a1,&b1);

45             union2(a1,b1);

46         }

47         int ans=0;

48         for(int i=1; i<=n; i++)

49         {

50             if(f[i]==i) ans++;

51         }

52         printf("%d\n",ans);

53     }

54     return 0;

55 }

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