PAT 甲级 1107 Social Clusters (30 分)

Note

• 并查集
• 模板题

Code

#include<bits/stdc++.h>
using namespace std;

int father[1010];

int find_father(int a){
	while(a!=father[a]) a=father[a];
	return a;
}

void union_(int a,int b){
	int fa=find_father(a);
	int fb=find_father(b);
	if(fa!=fb) father[fa]=fb;
}

bool cmp(int a,int b){
	return a>b;
}

int main(){
	#ifndef ONLINE_JUDGE
	freopen("data.txt","r",stdin);
	#endif
	
	int count[1010];
	memset(count,0,sizeof(count));
	int n,k,h;
	cin>>n;
	for(int i=1;i<=n;i++) father[i]=i;
	for(int i=1;i<=n;i++){
		scanf("%d:",&k);
		for(int j=0;j<k;j++){
			scanf("%d",&h);
			if(count[h]==0) count[h]=i;
			union_(i,count[h]);
		}
	}
	
	int cnt=0;
	memset(count,0,sizeof(count));
	for(int i=1;i<=n;i++){
		if(father[i]==i) cnt++;
		count[find_father(i)]++;
	}
	sort(count,count+1010,cmp);
	printf("%d\n",cnt);
	for(int i=0;i<cnt;i++){
		if(i!=0) printf(" ");
		printf("%d",count[i]);
	}
	
	return 0;
}