并查集的裸题，时间很充裕，只要路径压缩怎么写都能过。

自己第一次写的cin版本跑了7000ms。

#include<bits/stdc++.h>
using namespace std;
typedef pair<int,int> PII;
unordered_map<int,int> father;
int n,t;
vector<PII> v;
int find(int a)
{
    if (father[a] != a) father[a] = find(father[a]);
    return father[a];
}

void Union(int a,int b)
{
    int fa = find(a);
    int fb = find(b);
    if (fa == fb) return ;
    father[fb] = fa;
}
int main()
{
    scanf("%d",&t);
    while (t--)
    {
        father.clear();
        v.clear();
        scanf("%d",&n);
        for (int i = 1;i <= n;i++)
        {
            int a,b,c;
            scanf("%d%d%d",&a,&b,&c);
            if (father[a] == 0) father[a] = a;
            if (father[b] == 0) father[b] = b;
            if (c == 1) Union(a,b);
            else v.push_back({a,b});
        }

        bool flag = true;
        for (int i = 0;i < v.size();i++)
        {
            int fa = find(v[i].first);
            int fb = find(v[i].second);
            if (fa == fb)
            {
                flag = false;
                break;
            }
        }

        if (flag) printf("YES\n");
        else printf("NO\n");
    }
}