// 4k 4k+3

#include <stdio.h>
#include <algorithm>
#include <iostream>

using namespace std;

#define next NEXT

const int MAXN = 100000 + 10;
const int MOD = 1000000000 + 7;

int a[MAXN], b[MAXN], pos[MAXN], ret, fw[MAXN], tn, n, k, fac[MAXN], next, type_a, type_b;

int get_permutation_rank (int *a, int mod) {
    fac[0] = 1;
    int ret = 0;
    for(int i = 1; i <= n; i++)
        fw[i] = 0, fac[i] = (fac[i - 1] * 1LL * i) % mod;
    for(int i = 1; i <= n; i++) {
        int kk = 0;
        for(int j = a[i] - 1; j > 0; j &= (j - 1))
            kk += fw[j];
        kk = a[i] - 1 - kk;
        ret = (ret + fac[n - i] * 1LL * kk) % mod;
        for(int j = a[i]; j <= n; j = 2 * j - (j & (j - 1)))
            ++fw[j];
    }
    return ret;
}

bool inv (int *a) {
    for(int i = 1; i <= n; i++)
        fw[i] = 0;
    long long cnt = 0;
    for(int i = 1; i <= n; i++) {
        cnt += i - 1;
        for(int j = a[i]; j > 0; j &= (j - 1))
            cnt -= fw[j];
        for(int j = a[i]; j <= n; j = 2 * j - (j & (j - 1)))
            ++fw[j];
    }
    return cnt % 2;
}

int main () {
    ios_base::sync_with_stdio(false);
    cin >> tn;
    while (tn--) {
        cin >> n >> k;
        for(int i = 1; i <= n; i++) {
            cin >> b[i];
            pos[b[i]] = i;
        }
        for(int i = 1; i <= n; i++)
            cin >> a[i];
        
        if (k == n) {
            bool fail = false;
            for(int i = 2; i <= n; i++) {
                if (pos[a[i - 1]] == n)
                    next = 1;
                else
                    next = pos[a[i - 1]] + 1;
                if (next != pos[a[i]])
                    fail = true;
            }
            if (!fail)
                cout << a[1] << endl;
            else
                cout << -1 << endl;
            continue;
        }
        
        int rank_a = get_permutation_rank(a, 4);
        int rank_b = get_permutation_rank(b, 4);
        
        type_a = (rank_a == 0 || rank_a == 3);
        
        if (k % 2 == 0) {
            cout << (get_permutation_rank(a, MOD) + 1) % MOD << endl;
            continue;
        }
        
        if (inv(a) != inv(b)) {
            cout << -1 << endl;
            continue;
        }
        
        int q = get_permutation_rank(a, MOD);
        
        q = ((q - rank_a + MOD) * 500000004LL) % MOD;
        if (type_a == 1) {
            if (rank_a == 3)
                ++q;
        } else {
            if (rank_a == 2) ++q;
        }
        
        cout << (q + 1) % MOD << endl;
        
    }
    return 0;
}