When register on a social network, you are always asked to specify your hobbies in order to find some potential friends with the same hobbies. A social cluster is a set of people who have some of their hobbies in common. You are supposed to find all the clusters.
当你在一个社交网络上注册的时候，你经常会被要求具体填写你的爱好以便找到和你有相同爱好的潜在朋友。一个社会群体是一群拥有共同兴趣爱好的人。你需要找到所有社会群体、
Input Specification:
Each input file contains one test case. For each test case, the first line contains a positive integer N (≤1000), the total number of people in a social network. Hence the people are numbered from 1 to N. Then N lines follow, each gives the hobby list of a person in the format:
Ki: hi[1] hi[2] ... hi[Ki]
where Ki (>0) is the number of hobbies, and hi[j] is the index of the j-th hobby, which is an integer in [1, 1000].
第一行包含一个正整数N(<1000)，代表一个社会群体里的总人数，所以人们从1-N进行编号。
后面有N行，每一行给出了一个人的兴趣列表，格式如下：Ki: hi[1] hi[2]....hi[k]
Ki代表兴趣总量，hi[j]代表第j个兴趣爱好。 hi[j]是【1,1000】内的一个整数
Output Specification:
For each case, print in one line the total number of clusters in the network. Then in the second line, print the numbers of people in the clusters in non-increasing order. The numbers must be separated by exactly one space, and there must be no extra space at the end of the line.
第一行打印出这个网络中群体的总量。第二行以非递增顺序打印出在这些群体中人的数量。
#include<cstdio>
#include<algorithm>
using namespace std;
const int N=1010;
int father[N];
int isRoot[N]={0};
int course[N]={0};
int findFather(int x){
int a=x;
while(x!=father[x]){
x=father[x];
}
while(a!=father[a]){
int z=a;
a=father[a];
father[z]=x;
}
return x;
}
void Union(int a,int b){
int faA=findFather(a);
int faB=findFather(b);
if(faA!=faB){
father[faA]=faB;
}
}
void init(int n){
for(int i=1;i<=n;i++){
father[i]=i;
isRoot[i]=false;
}
}
bool cmp(int a,int b){
return a>b;
}
int main(){
int n,k,h;
scanf("%d",&n);
init(n);
for(int i=1;i<=n;i++){
scanf("%d:",&k);
for(int j=0;j<k;j++){
scanf("%d",&h);
if(course[h]==0){//如果活动h第一次有人喜欢
course[h]=i;//令i喜欢活动h
}
Union(i,findFather(course[h]));//合并
}
}
for(int i=1;i<=n;i++){
isRoot[findFather(i)]++;
}
int ans=0;
for(int i=1;i<=n;i++){
if(isRoot[i]!=0){
ans++;
}
}
printf("%d\n",ans);
sort(isRoot+1,isRoot+n+1,cmp);//从大到小排序
for(int i=1;i<=ans;i++){
printf("%d",isRoot[i]);
if(i<ans) printf(" ");
}
return 0;
}