hdu 1213 How Many Tables

#include<stdio.h>
int bin[1024];
int findx(int x)
{
    while(bin[x]!=x)
        x=bin[x];
    return x;
}
void mergeab(int x,int y)
{
    int fx,fy;
    fx=findx(x);
    fy=findx(y);
    if(fx>fy)
    bin[fx]=fy;
    else bin[fy]=fx;
}
int main()
{
    int i,n,m,ans,a,b,T;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d%d",&n,&m);
        for(i=1;i<=n;i++)
            bin[i]=i;
        for(i=0;i<m;i++)
        {
            scanf("%d%d",&a,&b);
            mergeab(a,b);
        }
        for(i=1,ans=0;i<=n;i++)
        {
            if(bin[i]==i) ans++;
        }
        printf("%d
",ans);
    }
    return 0;
}