1107. Social Clusters (30) 并查集

#include <iostream>
#include <vector>
#include <algorithm>
#include <stack>
using namespace std;
int father[1001];
int hobby[1001];
int gnum[1001];

int find(int x){
while (x != father[x]) {
x = father[x];
}
return x;
}

void Union(int a, int b){
a = find(a);
b = find(b);
if(a < b) father[b] = a;
else father[a] = b;
}

void init(){
for (int i = 0; i < 1001; i++) {
father[i] = i;
}
}

int main(){
init();
int n;
cin >> n;

for (int i = 1; i <= n; i++) {
int k;
scanf("%d:", &k);
for (int j = 0; j < k; j++) {
int t;
scanf("%d", &t);
if(!hobby[t])
hobby[t] = i;
Union(i, find(hobby[t]));
}
}
for (int i = 1; i <= n; i++) {
gnum[find(i)]++;
}
int cnt = 0;
for (int i = 1; i <= n; i++) {
if(gnum[i] != 0) cnt++;
}
sort(gnum, gnum + 1001);
cout << cnt << endl;
for (int i = 1000; i > 1000 - cnt; i--) {
printf("%d%c", gnum[i], i == 1000-cnt+1 ? '\n' : ' ');
}

return 0;
}