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#pragma GCC optimize ("Ofast")
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define FOR(i, a, b) for (auto i=(a); i<(b); i++)
#define FORD(i, a,  b) for (auto i=(a); i>(b); i--)
#define SZ(x) ((int)(x).size())
#define ITH_BIT(m, i) ((m)>>(i) & 1)
#define PPC(x) __builtin_popcount(x)

#ifdef DEBUG
#include "debug.h"
#else
#define dbg(...) 0
#endif
template <typename T1, typename T2> inline void remin(T1& a, T2 b) { a = std::min(a, (T1)b);	}
template <typename T1, typename T2> inline void remax(T1& a, T2 b) { a = std::max(a, (T1)b);	}

const int maxN = 1 << 22, mod = 1'000'000'007;

template <typename T1, typename T2> inline void addMod(T1& a, T2 b) { a = (a + b) % mod; }
template <typename T1, typename T2> inline void multMod(T1& a, T2 b) { a = a * b % mod; }

long long fact[maxN], halfPow[maxN];
int n, m, segs;
int T[maxN / 2];

void precomp()
{
	long long half = (mod + 1) / 2;
	fact[0] = halfPow[0]  = 1;

	FOR(i, 1, maxN)
	{
		fact[i] = fact[i-1] * i % mod;
		halfPow[i] = halfPow[i-1] * half % mod;
	}
}

long long fillUp(int takenOnes, int takenTwos)
{
	int cards = m * 2 - takenOnes - takenTwos * 2;
	int freeTwos = m - takenOnes - takenTwos;

	if (takenOnes + takenTwos > m)
		return 0;
	else
		return fact[cards] * halfPow[freeTwos] % mod;
}

long long f(int newSolos, long long newSolosCombs, bool newPaired, bool additionalTheirSolo)
{
	long long mult = newSolosCombs;
	int ourSolos = segs + newSolos;
	if (newPaired)
		multMod(mult,  ourSolos--);

	int theirSolos = segs + additionalTheirSolo;
	int solosTotal = ourSolos + theirSolos;
	return mult * fillUp(solosTotal, newPaired);
}

long long profitFromPref(int suf)
{
	int prefSpots = n - suf/2;
	int prefSpotsOnes = segs;
	int prefSpotsFree = prefSpots - prefSpotsOnes;

	bool additionalMaxsSolo = suf % 2 == 0;
		
	long long profitSolo = f(1, prefSpotsFree, false, additionalMaxsSolo);
	long long profitPaired = f(0, 1, true, additionalMaxsSolo);
	
	long long profitPref = profitSolo + profitPaired;
	return profitPref;
}

long long profitFromSuf(int suf)
{
	int sufSpots = suf / 2;
	int spotsFree = (n - segs - 1);

	long long sufSolosCombs = 1ll * sufSpots * spotsFree % mod;
	bool additionalMaxsSolo = suf % 2 == 0;

	long long profitSolos = f(2, sufSolosCombs, false, additionalMaxsSolo);
	long long profitPaired = f(1, sufSpots, true, additionalMaxsSolo);

	long long profitSuf = profitSolos + profitPaired;
	return profitSuf;
}

long long profit(int suf)
{
	return (profitFromPref(suf) + profitFromSuf(suf)) % mod;
}

long long resultOnMono(int x)
{
	long long dominSeparated = fillUp(2, 0);
	multMod(dominSeparated, n);
	multMod(dominSeparated, n-1);

	long long dominTogether = fillUp(0, 1) * n;
	long long domin = (dominSeparated + dominTogether) % mod;

	long long drawSeparated = fillUp(3, 0);
	multMod(drawSeparated, m);
	multMod(drawSeparated, n);
	multMod(drawSeparated, n-1);

	long long drawTogether = fillUp(1, 1);
	multMod(drawTogether, m);
	multMod(drawTogether, n);

	long long draw = (drawSeparated + drawTogether) % mod;
	return x == 1 ? draw : domin;
}

void solve()
{
	scanf ("%d", &n);
	m = n * 2, segs = 0;
	int suf = 0, visMask = 0;

	FOR(i, 0, m)
	{
		scanf ("%d", T+i);
		visMask |= 1 << T[i];
	}
	T[m] = T[0];

	if (visMask != 3 and visMask != 6)
	{
		long long res = (visMask & 5) == 5
			? 0
			: resultOnMono(T[0]);
		printf("%lld\n", res);
		return;
	}
	
	FORD(i, m-1, -1)
	{
		if (T[i] == 1 and T[i+1] != 1)
			segs++;
		if (T[i] != T[i+1])
			suf = 0;
		suf++;
	}

	long long res = 0;
	bool dominParity = visMask & 4;

	auto validMaxsSpot = [&](int i) -> bool
	{
		bool sufOfOnes = T[i+1] == 1;
		bool sufEven = suf % 2 == 0;

		bool validSuf = sufOfOnes == sufEven;
		bool maxShallDomin = i % 2 == dominParity;

		return T[i] == 1
			and validSuf
			and maxShallDomin;
	};

	FORD(i, m-1, -1)
	{
		if (validMaxsSpot(i))
			res += profit(suf);
		
		if (T[i] != T[i+1])
		{
			if (suf % 2 == 0)
			{
				res = 0;
				break;
			}
			suf = 0;
		}
		suf++;
	}
	res %= mod;
	printf("%lld\n", res);
}

int main()
{
	int tc = 1;
	scanf ("%d", &tc);
	precomp();

	FOR(cid, 1, tc+1)
	{
//		printf("Case #%d: ", cid);
		solve();
	}
	return 0;
}