func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MOD = 1000000007;   template <typename T>   struct modular {     constexpr modular() : val(0) {}     constexpr modular(const modular<T>& _m) : val(_m.val) {}     template <typename U>     constexpr modular(const U& _r = U()) {       val = -MOD <= _r && _r < MOD ? _r : _r % MOD;       if (val < 0) {         val += MOD;       }     }     const T operator()() { return val; }     template <typename U>     explicit operator U() const {       return static_cast<U>(val);     }     modular<T>& operator+=(const modular<T>& _m) {       if ((val += _m.val) >= MOD) {         val -= MOD;       }       return *this;     }     modular<T>& operator-=(const modular<T>& _m) {       if ((val -= _m.val) < 0) {         val += MOD;       }       return *this;     }     modular<T>& operator*=(const modular<T>& _m) {       val = modular<T>(static_cast<int64_t>(val) * static_cast<int64_t>(_m.val))                 .val;       return *this;     }     modular<T>& operator/=(const modular<T>& _m) {       T a = _m.val, b = MOD, u = 0, v = 1;       while (a != 0) {         T q = b / a;         b -= q * a;         swap(a, b);         u -= q * v;         swap(u, v);       }       return *this *= u;     }     modular<T>& operator=(const modular<T>& _m) {       val = _m.val;       return *this;     }     template <typename U>     modular<T>& operator+=(const U& _r) {       return *this += modular<T>(_r);     }     template <typename U>     modular<T>& operator-=(const U& _r) {       return *this -= modular<T>(_r);     }     template <typename U>     modular<T>& operator*=(const U& _r) {       return *this *= modular<T>(_r);     }     template <typename U>     modular<T>& operator/=(const U& _r) {       return *this /= modular<T>(_r);     }     template <typename U>     modular<T>& operator=(const U& _r) {       val = modular<T>(_r).val;       return *this;     }     modular<T> operator-() { return modular<T>(-val); }     template <typename U>     friend bool operator==(const modular<U>&, const modular<U>&);     friend std::istream& operator>>(std::istream& os, modular<T>& _m) {       os >> _m.val;       _m *= 1;       return os;     }     friend std::ostream& operator<<(std::ostream& os, const modular<T>& _m) {       return os << _m.val;     }     template <typename U>     modular<T> exp(U e) {       modular<T> res = 1;       modular<T> b = val;       if (e < 0) {         b = 1 / b;         e *= -1;       }       for (; e; e >>= 1) {         if (e & 1) {           res *= b;         }         b *= b;       }       return res;     }       private:     T val;   };   template <typename T>   inline modular<T> operator+(const modular<T>& _lhs, const modular<T>& _rhs) {     return modular<T>(_lhs) += _rhs;   }   template <typename T, typename U>   inline modular<T> operator+(const modular<T>& _lhs, const U& _rhs) {     return modular<T>(_lhs) += _rhs;   }   template <typename T, typename U>   inline modular<T> operator+(const U& _lhs, const modular<T>& _rhs) {     return modular<T>(_lhs) += _rhs;   }   template <typename T>   inline modular<T> operator-(const modular<T>& _lhs, const modular<T>& _rhs) {     return modular<T>(_lhs) -= _rhs;   }   template <typename T, typename U>   inline modular<T> operator-(const modular<T>& _lhs, const U& _rhs) {     return modular<T>(_lhs) -= _rhs;   }   template <typename T, typename U>   inline modular<T> operator-(const U& _lhs, const modular<T>& _rhs) {     return modular<T>(_lhs) -= _rhs;   }   template <typename T>   inline modular<T> operator*(const modular<T>& _lhs, const modular<T>& _rhs) {     return modular<T>(_lhs) *= _rhs;   }   template <typename T, typename U>   inline modular<T> operator*(const modular<T>& _lhs, const U& _rhs) {     return modular<T>(_lhs) *= _rhs;   }   template <typename T, typename U>   inline modular<T> operator*(const U& _lhs, const modular<T>& _rhs) {     return modular<T>(_lhs) *= _rhs;   }   template <typename T>   inline modular<T> operator/(const modular<T>& _lhs, const modular<T>& _rhs) {     return modular<T>(_lhs) /= _rhs;   }   template <typename T, typename U>   inline modular<T> operator/(const modular<T>& _lhs, const U& _rhs) {     return modular<T>(_lhs) /= _rhs;   }   template <typename T, typename U>   inline modular<T> operator/(const U& _lhs, const modular<T>& _rhs) {     return modular<T>(_lhs) /= _rhs;   }   template <typename T>   inline bool operator==(const modular<T>& _lhs, const modular<T>& _rhs) {     return _lhs.val == _rhs.val;   }   template <typename T, typename U>   inline bool operator==(const modular<T>& _lhs, const U& _rhs) {     return _lhs == modular<T>(_rhs);   }   template <typename T, typename U>   inline bool operator==(const U& _lhs, const modular<T>& _rhs) {     return modular<T>(_lhs) == _rhs;   }   template <typename T>   inline bool operator!=(const modular<T>& _lhs, const modular<T>& _rhs) {     return !(_lhs == _rhs);   }   template <typename T, typename U>   inline bool operator!=(const modular<T>& _lhs, const U& _rhs) {     return !(_lhs == _rhs);   }   template <typename T, typename U>   inline bool operator!=(const U& _lhs, const modular<T>& _rhs) {     return !(_lhs == _rhs);   }   string to_string(string s) { return     + s +    ; }   string to_string(bool x) { return (x ?  T  :  F ); }   string to_string(modular<int> x) { return to_string(int(x)); }   string to_string(const char* s) { return to_string((string)s); }   template <typename A, typename B>   string to_string(pair<A, B> p) {     return  (  + to_string(p.first) +  ,   + to_string(p.second) +  ) ;   }   template <typename V>   string to_string(V v) {     bool f = true;     string res =  [ ;     for (const auto& x : v) {       if (!f) res +=  ,  ;       f = false;       res += to_string(x);     }     res +=  ] ;     return res;   }   void debug() { cerr << endl; }   template <typename H, typename... T>   void debug(H h, T... t) {     cerr <<     << to_string(h);     debug(t...);   }   const int N = 5050;   modular<int> a[N], c[N], dn[N][N << 1], res[N << 1];   void solve() {     int n;     cin >> n;     for (int i = 1; i < n; i++) {       cin >> a[i];     }     c[1] = 1;     for (int i = 1; i < n; i++) {       c[i + 1] = c[i] * a[i];     }     for (int i = n; i >= 1; i--) {       dn[i][0] = 1;       for (int j = 1; i + j <= n; j++) {         dn[i][j] = a[i] * dn[i + 1][j - 1];         res[j] += dn[i][j] * c[i];       }     }     for (int i = 1; i <= n; i++) {       dn[i][0] = 1;       for (int j = 2 * n - 2; j >= 1; j--) {         dn[i][j] = dn[i - 1][j - 1];         res[j] += dn[i][j] * c[i];         dn[i][j] += (a[i] - 1) * dn[i + 1][j - 1];       }     }     modular<int> half = modular<int>(1) / 2;     for (int j = 1; j <= 2 * n - 2; j++) {       cout << res[j] * half <<    ;     }   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     solve();     cout << endl;   }   