1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
#include "bits/stdc++.h"
using namespace std;

const long long MAX_VAL = 1000000007;

long long silnia(long long base) {
    if(base == 0) {
        return 1;
    }
    long long result = base;
    base--;
    while(base > 1) {
        result *= base;
        result %= MAX_VAL;
    }

    return result;
}

long long pow2(long long up) {
    long long result = 1;
    while(up > 0) {
        result<<1;
        result %= MAX_VAL;
        up--;
    }
    return result;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int t;
    cin >> t;

    for(int i=0; i<t; i++) {
        int n;
        cin>>n;

        vector<int> points;
        points.resize(n*2);
        map<int, int> points_map;
        for(int j=0; j<n*2; j++) {
            cin>>points[j];
            points_map[points[j]]++;
        }

        if(points_map[0] != 0 && points_map[2] != 0) {
            cout<<0<<"\n";
            continue;
        }

        int result = 0;

        if(points_map[0] == n*2 || points_map[2] == n*2) {
            long long q = silnia(n*4 - 2) / pow2(n*2-1);
            long long first = (n * q) % MAX_VAL;
            long long w = silnia(n*4 - 4) / pow2(n*2-2);
            long long second = n*(n-1);
            second %= MAX_VAL;
            second *= n*4 - 2;
            second %= MAX_VAL;
            second *= n*4 - 3;
            second %= MAX_VAL;
            second *= w;
            second %= MAX_VAL;

            result = (first + second) % MAX_VAL;
        }

        

        cout<<result<<"\n";
    }

    return 0;

}