POJ2524 并查集水题

#include
int father[50001];
int find(int p)
{
    return p == father[p] ? p : (father[p] = find(father[p]));
}
void merge(int a,int b)
{
    int x = find(a);
    int y = find(b);
    if (x != y)
    father[y] = x;
}
int main()
{
        int m,n;
        int i;
        int a,b;
        int q;
        int num = 0;
        while(scanf("%d%d",&n,&m))
        {
            num++;
            q = 0;
            if(n == 0 && m == 0)
            break;
            for(i = 1;i <= n;i++)
            father[i]=i;
            for (i = 0; i < m;i++)
            {
                    scanf("%d%d",&a,&b);
                    merge(a,b);
            }
            for (i = 1;i <= n;i++)
            {
                if(father[i] == i)
                q++;
            }
            printf("Case %d: %d\n",num,q);
        }
        return 0;
}