PAT (Advanced Level) 1107. Social Clusters (30)

简单并查集。

#include<cstdio>
#include<cstring>
#include<cmath>
#include<vector>
#include<map>
#include<queue>
#include<stack>
#include<algorithm>
using namespace std;

const int maxn=+;
int fa[maxn];
int num[maxn];
int n;
vector<int>g[maxn],ans;

int f(int x)
{
    if(x!=fa[x]) fa[x]=f(fa[x]);
    return fa[x];
}

int main()
{
    scanf("%d",&n);
    for(int i=;i<=n;i++)
    {
        int num; scanf("%d:",&num);
        while(num--)
        {
            int hob; scanf("%d",&hob);
            g[hob].push_back(i);
        }
    }

    for(int i=;i<=n;i++) fa[i]=i;

    for(int i=;i<=;i++)
    {
        if(g[i].size()==) continue;
        int u=f(g[i][]);
        for(int j=;j<g[i].size();j++)
        {
            int v=f(g[i][j]);
            if(u!=v) fa[v]=u;
        }
    }

    for(int i=;i<=n;i++) f(i);

    memset(num,,sizeof num);
    for(int i=;i<=n;i++) num[f(i)]++;
    for(int i=;i<=n;i++) if(num[i]>) ans.push_back(num[i]);

    sort(ans.begin(),ans.end());
    printf("%d\n",ans.size());
    for(int i=ans.size()-;i>=;i--)
    {
        printf("%d",ans[i]);
        if(i>) printf(" ");
        else printf("\n");
    }

    return ;
}