支持删除的并查集 hdu2473

题解：

代码：

#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn=5000050;
int fa[maxn],id,vis[maxn];
int find(int x)
{
   if (x!=fa[x]) fa[x]=find(fa[x]);  return(fa[x]);  
} 
void merge(int x,int y)
{
  int fx=find(x),fy=find(y);
  if (fx!=fy) fa[fx]=fy;
}
void del(int x)
{
  fa[x]=++id;
}
int main()
{
      freopen("noip.in","r",stdin);
      freopen("noip.out","w",stdout);
      int n,m,Case=0;
      while (scanf("%d%d",&n,&m),n+m)
      {
          for (int i=1;i<=n;i++) fa[i]=i+n;
          for (int i=n+1;i<=n+n+m;i++) fa[i]=i;
          id=n+n;
          int a,b;char ch[5];
          for (int i=1;i<=m;i++)
          {
            cin>>ch;
            if (ch[0]=='M')
            {
              cin>>a>>b;
              merge(a,b);
            }
            else
            {
              cin>>a;
              del(a);
            }
          }
          int ans=0;
          memset(vis,0,sizeof(vis));
          for (int i=1;i<=n;i++)
          {
              int x=find(i);
              if (!vis[x]) ans++,vis[x]=1;  
          } 
          printf("Case #%d: %d\n",++Case,ans);
      }
      return 0;
}