1107. Social Clusters (30)

并查集，路径压缩忘记怎么写，然后他是从1开始的。。。我一开始从0开始，不知道为什么错了，找了很久。。

#include<iostream>
#include<string>
#include<map>
#include<vector>
#include<algorithm>
#include<queue>
#include<set>
#include<stack>
using namespace std;

int hobby[1001];
int father[1001];
int num;

int findf(int x) {
    int a = x;
    while (father[x] != 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 fa = findf(a);
    int fb = findf(b);
    if (fa != fb) {
        father[fa] = fb;
    }
}

int main() {
    
    fill(hobby, hobby + 1001, 0);
    cin >> num;
    for (int i = 1; i <= num; i++) {
        father[i] = i;
    }

    for (int i = 1; i <= num; i++) {
        int n;
        scanf_s("%d: ", &n);
        for (int j = 1; j <= n; j++) {
            int temp;
            cin >> temp;
            if (hobby[temp] == 0) {
                hobby[temp] = i;
            }

            
                Union(i, findf(hobby[temp]));
            

        }
    }
    int count[1001];
    fill(count, count + 1001, 0);
    for (int i = 1; i <= num; i++) {
        count[findf(i)]++;
    }
    sort(count, count + 1001);
    reverse(count, count + 1001);

    int k=0;
    while (count[k] != 0) {
        k++;
    }
    cout << k<<endl;
    for (int i = 0; i < k; i++) {
        if (i == 0) cout << count[i];
        else cout << ' ' << count[i];
    }

    system("pause");
    
}