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#ifndef UNCLE
 #pragma GCC optimize("O3,unroll-loops")
#endif

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

#define FOR(i,p,q) for(int i=(p); i<=(q); ++i)
#define ROF(i,p,q) for(int i=(p); i>=(q); --i)
#define REP(i,q) for(int i=0; i<(q); ++i)
#define pb push_back
#define as assign
#define rz resize
#define Co const
#define al(X) X.begin(), X.end()
#define ral(X) X.rbegin(), X.rend()
#define sz(X) (int)((X).size())
#define ckmx(a,b) a=max(a,b)
#define ckmn(a,b) a=min(a,b)
#define V vector
typedef long long ll;
typedef long double ld;
typedef mt19937_64 mt;
#ifndef UNCLE
 typedef basic_string<bool> vb;
 typedef basic_string<int> vi;
 typedef basic_string<ll> vl;
#else
 typedef V<bool> vb;
 typedef V<int> vi;
 typedef V<ll> vl;
#endif

constexpr ll INFl=(ll)1e18+14, MD=(ll)1e9+7;
constexpr int INFi=1e9+14, MX_N=1e6+5,MX_M=MX_N*4+2;

ll Qpw(ll v,ll x){
    ll pr=1;
    while(x){
        if(x&1) pr=(pr*v)%MD;
        v=(v*v)%MD;
        x/=2;
    }
    return pr;
}
int N,M,Q;
vl fct,rfct,pw2,rpw2;

void Prp(){
    fct.as(MX_M+1,1),rfct.as(MX_M+1,1),pw2.as(MX_M+1,1),rpw2.as(MX_M+1,1);
    FOR(i,1,MX_M) fct[i]=(fct[i-1]*i)%MD, pw2[i]=(pw2[i-1]*2)%MD;
    rfct[MX_M]=Qpw(fct[MX_M],MD-2),rpw2[MX_M]=Qpw(pw2[MX_M],MD-2);
    ROF(i,MX_M-1,0) rfct[i]=(rfct[i+1]*(i+1))%MD, rpw2[i]=(rpw2[i+1]*2)%MD;
}
inline ll Nwt(ll n,ll k)noexcept {
    return ((fct[n]*rfct[k])%MD*rfct[n-k])%MD;
}
inline ll Rozd(ll dw,ll jed)noexcept {//mowie jakie zajete
    if(dw+jed>2*N||dw<0||jed<0) return 0;
    ll cd=2*N-dw-jed, cj=jed;
    ll n=2*cd+cj;
    return (((Nwt(n,cj)*fct[cj])%MD*fct[2*cd])%MD*rpw2[cd])%MD;//ig ze ok
}
inline int GtI()noexcept {
    char c;
    while((c=getchar_unlocked())<'0');
    int pr=c-'0';
    while((c=getchar_unlocked())>='0') pr=pr*10+c-'0';
    return pr;
}
void PtL(ll v)noexcept {
    string cs;
    if(v==0) cs="0";
    else{
        while(v) cs.push_back(v%10+'0'),v/=10;
    }
    ROF(i,sz(cs)-1,0) putchar_unlocked(cs[i]);
    putchar_unlocked((char)'\n');
}
void Inpt([[maybe_unused]] int ct){
    N=GtI();
    vi s(4*N,-1), qqt(3,0);
    int qtA=1;
    REP(i,2*N){
        s[i]=GtI();
        ++qqt[s[i]];
        if(s[i]==1) s[i]=0;
        else s[i]=1;
        if(i&&s[i]!=s[i-1]) ++qtA;
    }
    REP(i,2*N) s[i+2*N]=s[i];
    if(qqt[0]&&qqt[2]){ PtL((ll)0); return;}
    else if(qqt[0]+qqt[2]==2*N){ //zawsze wygrywam
        ll rs=(N*Rozd(1,0))%MD;
        if(N>=2) rs=(rs+(N*(N-1))%MD*Rozd(0,2))%MD;
        PtL(rs);
        return;
    }
    int dd=-1;
    if(qqt[0]!=0) dd=0; //jaka parzystość wygrywa;
    else dd=1;
    if(s[0]==s[2*N-1]) --qtA;
    ll rs=0;
    vi ri(4*N,-1),li(4*N,INFi),mxl(4*N,INFi);
    ri[4*N-1]=4*N-1;
    ROF(i,4*N-2,0){
        if(s[i]!=s[i+1]) ri[i]=i;
        else ri[i]=ri[i+1];
    }
    li[0]=-1,mxl[0]=-1;
    FOR(i,1,4*N-1){
        if(s[i]!=s[i-1]) li[i]=i-1;
        else li[i]=li[i-1];
        if(li[i]==-1) mxl[i]=-1;
        else{
            if(!((li[i]-i)&1)) mxl[i]=li[i];
            else mxl[i]=mxl[li[i]];
        }
    }
    V<vl> rozd(2,vl(5,-1));
    REP(i,2) REP(j,5) rozd[i][j]=Rozd(i,j+qtA-1);
    FOR(p,0,2*N-1){
        int q=p+2*N-1;
        if((q&1)!=dd||s[q]==1) continue;
        if(p<=mxl[q]) continue;
        int qt=qtA,ls=min(ri[p],q);
        if(s[p]==s[q]) ++qt;
        //buduje dwa takie same, inne odemnie
        ll d=ls-p,qtm=N-1-(qt>>1);
        if(d>=1&&qtm>=1) rs+=(((d+1)>>1)*qtm)%MD*rozd[0][qt+2-qtA+1];//drugi sam
        if(d>=1) rs+=(((d+1)>>1)*(N-qtm))%MD*rozd[1][qt-qtA+1];//drugi na kimś (jedna dwójka)
        //buduje jednego nowego po prawo róznego
        d=q-ls;
        ll qton=qt>>1;
        qtm=((d+1)>>1)-qton;
        if(qtm>=1) rs+=(qtm*rozd[0][qt+1-qtA+1]);//jako nowy
        if(qton>=1) rs+=(qton*rozd[1][qt-1-qtA+1]);//na kogos - wywalilem mod
        rs%=MD;
    }
    if(qqt[0]+qqt[2]==0) rs=(rs*2)%MD;
    PtL(rs);
}
signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);

    Prp();
    int T=1;
    T=GtI();
    FOR(t,1,T) Inpt(t);
}