HDU 2473-Junk-Mail Filter-并查集删除

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int ls[2000000],_hash[2000000], d[2000000];
int find1(int x)
{
    return ls[x] == x ? x : ls[x]=(find1(ls[x]));
}

void add(int x, int y)
{
    int xx = find1(x);
    int yy = find1(y);
    if(xx != yy)
    {
        ls[yy] = xx;
    }
}

int main()
{
    int n, m, i;
    int ti = 1;
    while(~scanf("%d%d",&n,&m)&&(n+m))
    {
        int cnt = n;
        for(i = 0; i < 2000000; i++)
        {
            ls[i] = i;
            d[i] = i;
        }
        while(m--)
        {
            char c;
            getchar();
            scanf("%c",&c);
            if(c == 'M')
            {
                int u, v;
                scanf("%d%d",&u,&v);
                add(d[u],d[v]);
            }
            else
            {
                int u;
                scanf("%d",&u);
                d[u]=cnt++;
            }
        }
        memset(_hash,0,sizeof(_hash));
        int cont = 0;
        for(i = 0; i < n; i++)
        {
            int a = find1(d[i]);
            if(!_hash[a])
            {
                _hash[a] = 1;
                cont++;
            }
        }
         printf("Case #%d: %d\n",ti++,cont);
    }
    return 0;
}