func_code_string: #include <bits/stdc++.h>   using namespace std;      const int M = 1000000007;   struct mint {        int val = 0;        mint() {}        mint(int a) : val(a) {       while (val < 0) {         val += M;       }       while (val >= M) {         val -= M;       }     }        mint(long long a) : val(a % M) {       if (val < 0) {         val += M;       }     }        mint operator+=(mint oth) {       val += oth.val;       val -= (val >= M) ? M : 0;       return *this;     }        mint operator-=(mint oth) {       val -= oth.val;       val += (val < 0) ? M : 0;       return *this;     }        mint operator*=(mint oth) {       val = 1LL * val * oth.val % M;       return *this;     }        void operator++() {       ++val;       if (val == M) {         val = 0;       }     }        void operator--() {       --val;       if (val == -1) {         val = M - 1;       }     }        mint operator-() {       mint res;       res.val = (val == 0) ? 0 : M - val;       return res;     }        friend mint operator+(mint a, mint b) {       return mint(a) += b;     }        friend mint operator-(mint a, mint b) {       return mint(a) -= b;     }        friend mint operator*(mint a, mint b) {       return mint(a) *= b;     }        friend bool operator==(mint a, mint b) {       return a.val == b.val;     }        friend bool operator!=(mint a, mint b) {       return a.val != b.val;     }        friend ostream& operator<<(ostream &out, mint a) {       out << a.val;       return out;     }        friend mint pow(mint b, long long e = M - 2) {       mint res = 1;       while (e > 0) {         if (e % 2 == 1) {           res *= b;         }         b *= b;         e /= 2;       }       return res;     }      };      const int N = 40 + 1;      using state = tuple<int, int, int, int, map<int, int>>;      mint choose[N][N], fact[N];   bool visited[N];   int perm[N], n;      mint calc(int k) {     return choose[n][k + 1] * fact[k] * fact[n - k - 1];   }      int main() {     ios_base::sync_with_stdio(false);     cin.tie(nullptr);        for (int i = 0; i < N; ++i) {       choose[i][0] = choose[i][i] = 1;       fact[i] = (i == 0) ? 1 : fact[i - 1] * i;       for (int j = 1; j < i; ++j) {         choose[i][j] = choose[i - 1][j - 1] + choose[i - 1][j];       }     }        cin >> n;        for (int i = 0; i < n; ++i) {       cin >> perm[i];       --perm[i];     }        map<int, int> cycles;     for (int i = 0; i < n; ++i) {       if (!visited[i]) {         int j = i, l = 0;         while (!visited[j]) {           visited[j] = true;           j = perm[j];           ++l;         }         ++cycles[l];       }     }        mint ans = 0;     cycles[n + 1] = 0;     map<state, mint> ways;     ways.insert({{0, cycles.begin()->first, 0, 0, cycles}, 1});        while (!ways.empty()) {       auto [s, x] = *ways.begin();       auto [i, j, p, c, count] = s;       ways.erase(ways.begin());          if (j > n) {         if (c > 0) {           if (i + c == n) {             ans += x;           } else {             state t = {i + c, count.begin()->first, c, 0, count};             ways[t] += x;           }         }       } else {         mint y = pow(calc(n - i - 1), j);         if (p > 0) {           y -= pow(calc(n - i - 1 + p), j);         }            state t = {i, count.upper_bound(j)->first, p, c, count};         for (int k = 0; k <= count[j]; ++k) {           ways[t] += x * pow(y, k) * choose[count[j]][k];           get<3>(t) += j;           --get<4>(t)[j];         }       }     }        cout << ans <<   n ;   }   