暴力并查集 N - News Distribution

思路：并查集，最后再统计每个结点的父节点是哪个。
传送门

#include<cstdio>
#include<cstring>
#include<iostream>
using namespace  std;
int pre[500005];
int sum[500005];
int n, m;
int Find(int root)
{
    int son = root;
    while(pre[root] != root)
        root = pre[root];
    while(son != root)//tmp保存前驱结点
    {
        int tmp = pre[son];
        pre[son] = root;
        son = tmp;
    }
    return root;
}
int main()
{
    scanf("%d %d", &n, &m);
    for(int i = 1; i <= n; i++)
        pre[i] = i;
    int cnt = n;
    for(int i = 1; i <= m; i++)
    {
        int u, v;
        int t;
        scanf("%d", &t);
        int root1, root2;
        if(t != 0)
        {
            scanf("%d", &v);
            root1 = Find(v);
            t--;
        }
        while(t--)
        {

            scanf("%d", &u);
            root2 = Find(u);
            if(root1 != root2)
            {
                pre[root2] = root1;
                cnt--;
            }
        }
    }
    for(int i = 1;i <= n;i++)
    {
        pre[i] = Find(i);
        sum[pre[i]]++;
        //cout << pre[i] << endl;
    }
    for(int i = 1;i <= n;i++)
    {
        if(i == n)
        printf("%d",sum[pre[i]]);
        else printf("%d ",sum[pre[i]]);
    }
    return 0;
}