udmap 实现并查集。 水过啦~

#include<bits/stdc++.h>
using namespace std;

const int N=1e6+10;
int a[N],b[N],n,t,l;
unordered_map<int,int>fa;

inline int Find(int x)
{
	if(fa[x]==x)return x;
	return fa[x]=Find(fa[x]);
}
inline void Merge(int x,int y)
{
	int fx=Find(x),fy=Find(y);
	if(fx!=fy)fa[fx]=fy;
}
inline int Read()
{
	int f=1,x=0;
	char ch=getchar();
	while(!isdigit(ch) && ch^'-')ch=getchar();
	if(ch=='-')f=-1,ch=getchar();
	while(isdigit(ch))x=x*10+ch-'0',ch=getchar();
	return x*f;
}

signed main()
{
	t=Read();
	while(t--)
	{
		n=Read();
		bool flag=1;
		l=0;fa.clear();
		
		while(n--)
		{
			int x=Read(),y=Read(),opt=Read();
			if(fa[x]==0)fa[x]=x;
			if(fa[y]==0)fa[y]=y;
			
			if(opt==1)Merge(x,y);
			else a[++l]=x,b[l]=y;
		}
		for(int i=1;i<=l;++i)
		{
            if(Find(a[i])==Find(b[i]))
            {
            	flag=0;break;
			}
		}
		if(flag)puts("YES");
		else puts("NO");
	}
	return 0;
}