#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

struct UnionFind {
    vector<int> data;
    void init(int n) { data.assign(n, -1); }
    bool unionSet(int x, int y) {
        x = root(x); y = root(y);
        if(x != y) {
            if(data[y] < data[x]) swap(x, y);
            data[x] += data[y]; data[y] = x;
        }
        return x != y;
    }
    bool findSet(int x, int y) { return root(x) == root(y); }
    int root(int x) { return data[x] < 0 ? x : data[x] = root(data[x]); }
    int size(int x) { return -data[root(x)]; }
};


template<int MOD>
struct ModInt {
    static const int Mod = MOD;
    unsigned x;
    ModInt() : x(0) {}
    ModInt(signed sig) { int sigt = sig % MOD; if(sigt < 0) sigt += MOD; x = sigt; }
    ModInt(signed long long sig) { int sigt = sig % MOD; if(sigt < 0) sigt += MOD; x = sigt; }
    int get() const { return (int)x; }

    ModInt &operator+=(ModInt that) { if((x += that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator-=(ModInt that) { if((x += MOD - that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; }

    ModInt operator+(ModInt that) const { return ModInt(*this) += that; }
    ModInt operator-(ModInt that) const { return ModInt(*this) -= that; }
    ModInt operator*(ModInt that) const { return ModInt(*this) *= that; }
};
typedef ModInt<1000000007> mint;

int naivegetdist(int i, int p, int t, const vector<vi> &g) {
    if(i == t)
        return 0;
    each(j, g[i]) if(*j != p) {
        int d = naivegetdist(*j, i, t, g);
        if(d != -1)
            return d + 1;
    }
    return -1;
}

int naivegetsize(int i, int p, const vector<vi> &g) {
    int r = 1;
    each(j, g[i]) if(*j != p) {
        r += naivegetsize(*j, i, g);
    }
    return r;
}


int main() {
    static mint C[1000 + 1][1000 + 1];
    for(int i = 0; i <= 1000; i ++) {
        C[i][0] = 1;
        for(int j = 1; j <= i; j ++)
            C[i][j] = C[i - 1][j - 1] + C[i - 1][j];
    }
    int T;
    scanf("%d", &T);
    for(int ii = 0; ii < T; ++ ii) {
        int N; int K;
        scanf("%d%d", &N, &K);
        vector<int> c(N);
        for(int i = 0; i < N; ++ i) {
            scanf("%d", &c[i]);
        }
        UnionFind uf; uf.init(N);
        int cycles = 0;
        vpii cycleEdges;
        vector<vi> g(N);
        rep(i, N) {
            if(uf.unionSet(i, c[i])) {
                g[i].push_back(c[i]);
                g[c[i]].push_back(i);
            } else {
                cycleEdges.push_back(mp(i, c[i]));
            }
        }
        vpii sizes;
        each(i, cycleEdges) {
            int cycle = 1 + naivegetdist(i->first, -1, i->second, g);
            int size = naivegetsize(i->first, -1, g);
            sizes.push_back(mp(size, cycle));
        }
        vector<mint> dp(N + 1);
        dp[N] = 1;
        rep(i, sizes.size()) {
            int size = sizes[i].first, cycle = sizes[i].second;
            for(int j = 0; j <= N; ++ j) {
                mint x = dp[j];
                if(x.get() == 0) continue;
                dp[j] = mint();
                rer(k, 0, size - 1) {
                    mint a = x * (C[size][k] - (k >= cycle ? C[size - cycle][k - cycle] : mint()));
                    if(k % 2 == 0) dp[j - k] += a; else dp[j - k] -= a;
                }
                rer(k, cycle, size) {
                    mint a = x * C[size - cycle][k - cycle];
                    if(k % 2 == 0) dp[j - (k - 1)] += a; else dp[j - (k - 1)] -= a;
                }
            }
        }
        mint ans;
        mint coeff = 1;
        rer(j, 0, N) {
            ans += dp[j] * coeff;
            coeff *= K;
        }
        printf("%d\n", ans.get());
    }
    return 0;
}