Description：

Solution：

Code：

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstdio>

#include<cmath>

#include<map>

#include<vector>

#include<cstring>

using namespace std;

inline int read()

{

	register int res = 0;

	register char c = getchar();

	while(!isdigit(c))c = getchar();

	while(isdigit(c))

	{

		res = (res << 1) + (res << 3) + c - '0';

		c = getchar();

	}

	return res;

}

int n;

#define MAXN 100010

int f[MAXN << 1];

int find(int x){return (f[x] == x ? x : f[x] = find(f[x]));}

struct lin{int u,v,w;};

vector<lin> g;

map<int,int> fr;

int to[MAXN << 1],tot = 0;

int s[MAXN << 1];

void work()

{

	scanf("%d",&n);

	for(int i = 1;i <= 2 * n;++i)f[i] = i;

	int a,b,c;g.clear();

	for(int i = 1;i <= n;++i)

	{

		a = read();b = read();c = read();

		g.push_back((lin){a,b,c});

		s[2 * i - 1] = a;s[2 * i] = b;

	}

	sort(s + 1,s + 1 + 2 * n);

	fr.clear();tot = 0;

	memset(to,0,sizeof(to));

	for(int i = 1;i <= 2 * n;++i)

	{

		if(i == 1 || s[i] != s[i - 1])

		{

			fr[s[i]] = ++tot;

			to[tot] = s[i];

		}

	}

	for(vector<lin>::iterator i = g.begin();i != g.end();++i)

	{

		if(i -> w == 1)

		{

			if(find(fr[i -> u]) == find(fr[i -> v]))continue;

			f[find(fr[i -> u])] = find(fr[i -> v]);

		}

	}

	for(vector<lin>::iterator i = g.begin();i != g.end();++i)

	{

		if(i -> w == 0)

		{

			if(find(fr[i -> u]) == find(fr[i -> v]))

			{

				puts("NO");

				return;

			}

		}

	}

	puts("YES");

	return;

}

int main()

{

	int testcases = read();

	while(testcases--)work();

	return 0;

}