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.
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].
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.
Sample Input:
8
3: 2 7 10
1: 4
2: 5 3
1: 4
1: 3
1: 4
4: 6 8 1 5
1: 4
Sample Output:
3
4 3 1
#include<cstdio>
#include<algorithm>
#include<fstream>
using namespace std;
const int maxn=1010;
int father[maxn];
int course[maxn]={0};
int isroot[maxn]={0};
void init(int n){
for(int i=1; i<=n; i++){
father[i]=i;
isroot[i]=false;
}
}
int findfather(int x){
while(x!=father[x]){
x=father[x];
}
return x;
}
void Union(int a, int b){
int faA=findfather(a);
int faB=findfather(b);
if(faA!=faB){
father[faA]=faB;
}
}
bool cmp(int a, int b){
return a>b;
}
int main(){
int n, k, h;
// freopen("d://in.txt","r",stdin);
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){
course[h]=i;
}
Union(i, findfather(course[h]));
}
}
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, cmp);
for(int i=1; i<=ans; i++){
printf("%d", isroot[i]);
if(i<ans) printf(" ");
}
return 0;
}