五十求条

#include<bits/stdc++.h>
using namespace std;
const int N=2e5+10;
struct Node{
    int x,y,e;
    bool operator <(const Node b)const{
        return e>b.e;
    }
}a[N];
int f[N];
int find(int x){
    if(x==f[x]) return x;
    return f[x]=find(f[x]);
}
int main(){
    int T;
    cin>>T;
    while(T--)
    {
        bool flag=0;
        int n;
        cin>>n;
        map<int,int>mp;
        int id=0;
        for(int i=1;i<=n;i++){
            cin>>a[i].x>>a[i].y>>a[i].e;
        }
        sort(a+1,a+1+n);
        for(int i=1;i<=n;i++){
            if(mp[a[i].x]==0) mp[a[i].x]=++id;
            if(mp[a[i].y]==0) mp[a[i].y]=++id;
            int r=find(mp[a[i].x]),l=find(mp[a[i].y]);
            if(a[i].e){
                if(r!=l)f[r]=l;
            }else{
                if(r==l){
                    cout<<"NO"<<endl;
                    flag=1;
                    break;
                }
            }
        }
        if(flag==0)cout<<"YES"<<endl;
    }
    return 0;
}