666，阴间数据

#include<bits/stdc++.h>
using namespace std;
const int N=2e5+5;
int f[N],t;
bool target=0;
struct node{
    int i,j,e;
}s[N];
bool cmp(node x,node y){
    return x.e>y.e;
}
int find(int x){
    if(f[x]==x)return x;
    return f[x]=find(f[x]);
}
void merge(int x,int y){
    x=find(x);
    y=find(y);
    f[x]=y;
}
void solve(){
    int n;
    cin>>n;
    map<int,int>mp;
    int cnt=0;
    for(int i=1;i<=n;i++){
        int x,y,z;
        cin>>x>>y>>z;
        if(!mp.count(x))mp[x]=++cnt;
        if(!mp.count(y))mp[y]=++cnt;
        s[i]={mp[x],mp[y],z};
    }
    sort(s****+n+1,cmp);
    for(int i=1;i<=cnt;i++)f[i]=i;
    for(int i=1;i<=n;i++){
        if(s[i].e==1)merge(s[i].i,s[i].j);
        else if(find(s[i].i)==find(s[i].j)){
            cout<<"NO\n";
            return ;
        }
    }
    cout<<"YES\n";
    return ;
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin>>t;
    while(t--){
        solve();
    }
    return 0;
}