e· · · · · ·

#include<bits/stdc++.h>
using namespace std;
int t,n,f[1000007],book[1000007*3];
struct node{
    int x,y,e;
}a[1000001];  
bool cmp(node a,node b){
    return a.e>b.e;
}
inline void first(int kkk){
    for(int i=1;i<=kkk;i++)  f[i]=i;
}
int get(int x){
    if(x==f[x]) return x;
    return f[x]=get(f[x]);
}
int main(){
    scanf("%d",&t);
    while(t--){
      int tot=-1;
      memset(book,0,sizeof(book));
      memset(a,0,sizeof(a));
      memset(f,0,sizeof(f));
    int flag=1;
        scanf("%d",&n);
       
        for(int i=1;i<=n;i++){
            scanf("%d %d %d",&a[i].x,&a[i].y,&a[i].e);
            book[++tot]=a[i].x;
            book[++tot]=a[i].y;
        }
        sort(book,book+tot);
        int reu=unique(book,book+tot)-book;
        for(int i=1;i<=n;++i){
           a[i].x=lower_bound(book,book+reu,a[i].x)-book;
           a[i].y=lower_bound(book,book+reu,a[i].y)-book;   
        } 
        first(reu);  
        sort(a+1,a+n+1,cmp); 
        for(int i=1;i<=n;i++){
            int r1=get(a[i].x);
            int r2=get(a[i].y);
            if(a[i].e){
                f[r1]=r2;
            }else if(r1==r2){
                printf("NO\n");
                flag=0;  
                break;
            }
        }
        if(flag)    printf("YES\n");  
    }
    return 0;
}

using namespace std;
int t,n,f[1000007],book[1000007*3];
struct node{
    int x,y,e;
}a[1000001];  
bool cmp(node a,node b){
    return a.e>b.e;
}
inline void first(int kkk){
    for(int i=1;i<=kkk;i++)  f[i]=i;
}
int get(int x){
    if(x==f[x]) return x;
    return f[x]=get(f[x]);
}
int main(){
    scanf("%d",&t);
    while(t--){
      int tot=-1;
      memset(book,0,sizeof(book));
      memset(a,0,sizeof(a));
      memset(f,0,sizeof(f));
    int flag=1;
        scanf("%d",&n);
       
        for(int i=1;i<=n;i++){
            scanf("%d %d %d",&a[i].x,&a[i].y,&a[i].e);
            book[++tot]=a[i].x;
            book[++tot]=a[i].y;
        }
        sort(book,book+tot);
        int reu=unique(book,book+tot)-book;
        for(int i=1;i<=n;++i){
           a[i].x=lower_bound(book,book+reu,a[i].x)-book;
           a[i].y=lower_bound(book,book+reu,a[i].y)-book;   
        } 
        first(reu);  
        sort(a+1,a+n+1,cmp); 
        for(int i=1;i<=n;i++){
            int r1=get(a[i].x);
            int r2=get(a[i].y);
            if(a[i].e){
                f[r1]=r2;
            }else if(r1==r2){
                printf("NO\n");
                flag=0;  
                break;
            }
        }
        if(flag)    printf("YES\n");  
    }
    return 0;
}