#include #include "testlib.h" using namespace std; #define MOD 1000000007 long long gcd(long long x, long long y) { if (x < y) swap(x, y); while (y > 0) { long long r = x % y; x = y; y = r; } return x; } long long lcm(long long x, long long y) { return x * y / gcd(x, y); } const int MAX = 1020; long long fac[MAX], finv[MAX], inv[MAX]; void COMinit(long long mod) { fac[0] = fac[1] = 1; finv[0] = finv[1] = 1; inv[1] = 1; for (int i = 2; i < MAX; i++) { fac[i] = fac[i - 1] * i % mod; inv[i] = mod - inv[mod % i] * (mod / i) % mod; finv[i] = finv[i - 1] * inv[i] % mod; } } long long COM(long long n, long long k, long long mod) { if (n < k) return 0; if (n < 0 || k < 0) return 0; return fac[n] * (finv[k] * finv[n - k] % mod) % mod; } long long modpow(long long a, long long n, long long mod) { long long res = 1; while (n > 0) { if (n & 1) res = res * a % mod; a = a * a % mod; n >>= 1; } return res; } int main() { COMinit(MOD); long long N, M; registerValidation(); N = inf.readInt(1, 1000, "N"); inf.readSpace(); M = inf.readInt(1, 1000000000, "M"); vector A(N); inf.readEoln(); A[0] = inf.readInt(1, N, "A"); for (int i = 1; i < N; i++) { inf.readSpace(); A[i] = inf.readInt(1, N, "A"); } inf.readEoln(); inf.readEof(); vector flagtest(N, false); for (int i = 0; i < N; i++){ if (flagtest[A[i] - 1]) cout << -1 << endl; flagtest[A[i] - 1] = true; } vector chikan(N + 1); vector flag(N, false); for (int i = 0; i < N; i++) { if (flag[i]) continue; int i_ = A[i] - 1; flag[i_] = true; int count = 1; while (i != i_) { i_ = A[i_] - 1; count++; flag[i_] = true; } chikan[count]++; } vector> jun(N + 1); for (int i = 1; i <= N; i++) { jun[i / gcd(i, M)].push_back(i); } long long ans = 1; for (int i = 1; i <= N; i++) { vector dp(chikan[i] + 1, 0); dp[0] = 1; for (int j = 1; j <= chikan[i]; j++) { for (int k = 0; k < jun[i].size(); k++) { if (j < jun[i][k] / i) continue; dp[j] += ((dp[j - jun[i][k] / i] * COM(j - 1, jun[i][k] / i - 1, MOD) % MOD) * fac[jun[i][k] / i - 1] % MOD) * modpow(i, jun[i][k] / i - 1, MOD) % MOD; } dp[j] %= MOD; } ans = ans * dp[chikan[i]] % MOD; } cout << ans << endl; }