結果

問題 No.1856 Mex Sum 2
ユーザー 👑 emthrmemthrm
提出日時 2022-02-25 23:23:21
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
RE  
実行時間 -
コード長 20,359 bytes
コンパイル時間 3,561 ms
コンパイル使用メモリ 233,152 KB
実行使用メモリ 6,948 KB
最終ジャッジ日時 2024-07-03 18:24:52
合計ジャッジ時間 13,288 ms
ジャッジサーバーID
(参考情報)
judge1 / judge3
このコードへのチャレンジ
(要ログイン)

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 RE -
testcase_01 RE -
testcase_02 RE -
testcase_03 RE -
testcase_04 RE -
testcase_05 RE -
testcase_06 RE -
testcase_07 RE -
testcase_08 RE -
testcase_09 RE -
testcase_10 RE -
testcase_11 RE -
testcase_12 RE -
testcase_13 RE -
testcase_14 RE -
testcase_15 RE -
testcase_16 RE -
testcase_17 RE -
testcase_18 RE -
testcase_19 RE -
testcase_20 RE -
testcase_21 RE -
testcase_22 RE -
testcase_23 RE -
testcase_24 RE -
testcase_25 RE -
testcase_26 RE -
testcase_27 RE -
testcase_28 RE -
testcase_29 RE -
testcase_30 RE -
testcase_31 RE -
testcase_32 RE -
testcase_33 RE -
testcase_34 RE -
testcase_35 RE -
testcase_36 RE -
testcase_37 RE -
testcase_38 RE -
testcase_39 RE -
testcase_40 RE -
testcase_41 RE -
testcase_42 RE -
testcase_43 RE -
testcase_44 RE -
testcase_45 RE -
testcase_46 RE -
testcase_47 RE -
testcase_48 RE -
testcase_49 RE -
testcase_50 RE -
testcase_51 RE -
testcase_52 RE -
testcase_53 RE -
testcase_54 RE -
testcase_55 RE -
testcase_56 RE -
testcase_57 RE -
testcase_58 RE -
testcase_59 RE -
testcase_60 RE -
testcase_61 RE -
testcase_62 RE -
testcase_63 RE -
testcase_64 RE -
testcase_65 RE -
testcase_66 RE -
権限があれば一括ダウンロードができます

ソースコード

diff #

#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

template <int M>
struct MInt {
  unsigned int v;
  MInt() : v(0) {}
  MInt(const long long x) : v(x >= 0 ? x % M : x % M + M) {}
  static constexpr int get_mod() { return M; }
  static void set_mod(const int divisor) { assert(divisor == M); }
  static void init(const int x = 10000000) {
    inv(x, true);
    fact(x);
    fact_inv(x);
  }
  static MInt inv(const int n, const bool init = false) {
    // assert(0 <= n && n < M && std::__gcd(n, M) == 1);
    static std::vector<MInt> inverse{0, 1};
    const int prev = inverse.size();
    if (n < prev) {
      return inverse[n];
    } else if (init) {
      // "n!" and "M" must be disjoint.
      inverse.resize(n + 1);
      for (int i = prev; i <= n; ++i) {
        inverse[i] = -inverse[M % i] * (M / i);
      }
      return inverse[n];
    }
    int u = 1, v = 0;
    for (unsigned int a = n, b = M; b;) {
      const unsigned int q = a / b;
      std::swap(a -= q * b, b);
      std::swap(u -= q * v, v);
    }
    return u;
  }
  static MInt fact(const int n) {
    static std::vector<MInt> factorial{1};
    const int prev = factorial.size();
    if (n >= prev) {
      factorial.resize(n + 1);
      for (int i = prev; i <= n; ++i) {
        factorial[i] = factorial[i - 1] * i;
      }
    }
    return factorial[n];
  }
  static MInt fact_inv(const int n) {
    static std::vector<MInt> f_inv{1};
    const int prev = f_inv.size();
    if (n >= prev) {
      f_inv.resize(n + 1);
      f_inv[n] = inv(fact(n).v);
      for (int i = n; i > prev; --i) {
        f_inv[i - 1] = f_inv[i] * i;
      }
    }
    return f_inv[n];
  }
  static MInt nCk(const int n, const int k) {
    if (n < 0 || n < k || k < 0) return 0;
    return fact(n) * (n - k < k ? fact_inv(k) * fact_inv(n - k) :
                                  fact_inv(n - k) * fact_inv(k));
  }
  static MInt nPk(const int n, const int k) {
    return n < 0 || n < k || k < 0 ? 0 : fact(n) * fact_inv(n - k);
  }
  static MInt nHk(const int n, const int k) {
    return n < 0 || k < 0 ? 0 : (k == 0 ? 1 : nCk(n + k - 1, k));
  }
  static MInt large_nCk(long long n, const int k) {
    if (n < 0 || n < k || k < 0) return 0;
    inv(k, true);
    MInt res = 1;
    for (int i = 1; i <= k; ++i) {
      res *= inv(i) * n--;
    }
    return res;
  }
  MInt pow(long long exponent) const {
    MInt res = 1, tmp = *this;
    for (; exponent > 0; exponent >>= 1) {
      if (exponent & 1) res *= tmp;
      tmp *= tmp;
    }
    return res;
  }
  MInt& operator+=(const MInt& x) {
    if ((v += x.v) >= M) v -= M;
    return *this;
  }
  MInt& operator-=(const MInt& x) {
    if ((v += M - x.v) >= M) v -= M;
    return *this;
  }
  MInt& operator*=(const MInt& x) {
    v = static_cast<unsigned long long>(v) * x.v % M;
    return *this;
  }
  MInt& operator/=(const MInt& x) { return *this *= inv(x.v); }
  bool operator==(const MInt& x) const { return v == x.v; }
  bool operator!=(const MInt& x) const { return v != x.v; }
  bool operator<(const MInt& x) const { return v < x.v; }
  bool operator<=(const MInt& x) const { return v <= x.v; }
  bool operator>(const MInt& x) const { return v > x.v; }
  bool operator>=(const MInt& x) const { return v >= x.v; }
  MInt& operator++() {
    if (++v == M) v = 0;
    return *this;
  }
  MInt operator++(int) {
    const MInt res = *this;
    ++*this;
    return res;
  }
  MInt& operator--() {
    v = (v == 0 ? M - 1 : v - 1);
    return *this;
  }
  MInt operator--(int) {
    const MInt res = *this;
    --*this;
    return res;
  }
  MInt operator+() const { return *this; }
  MInt operator-() const { return MInt(v ? M - v : 0); }
  MInt operator+(const MInt& x) const { return MInt(*this) += x; }
  MInt operator-(const MInt& x) const { return MInt(*this) -= x; }
  MInt operator*(const MInt& x) const { return MInt(*this) *= x; }
  MInt operator/(const MInt& x) const { return MInt(*this) /= x; }
  friend std::ostream& operator<<(std::ostream& os, const MInt& x) {
    return os << x.v;
  }
  friend std::istream& operator>>(std::istream& is, MInt& x) {
    long long v;
    is >> v;
    x = MInt(v);
    return is;
  }
};
using ModInt = MInt<MOD>;

template <int T>
struct NumberTheoreticTransform {
  using ModInt = MInt<T>;

  NumberTheoreticTransform() {
    for (int i = 0; i < 23; ++i) {
      if (primes[i][0] == ModInt::get_mod()) {
        n_max = 1 << primes[i][2];
        root = ModInt(primes[i][1]).pow((primes[i][0] - 1) >> primes[i][2]);
        return;
      }
    }
    assert(false);
  }

  template <typename U>
  std::vector<ModInt> dft(const std::vector<U>& a) {
    const int n = a.size();
    int lg = 1;
    while ((1 << lg) < n) ++lg;
    std::vector<ModInt> b(1 << lg, 0);
    std::copy(a.begin(), a.end(), b.begin());
    calc(&b);
    return b;
  }

  void idft(std::vector<ModInt>* a) {
    const int n = a->size();
    assert(__builtin_popcount(n) == 1);
    calc(a);
    std::reverse(std::next(a->begin()), a->end());
    const ModInt inv_n = ModInt::inv(n);
    for (int i = 0; i < n; ++i) {
      (*a)[i] *= inv_n;
    }
  }

  template <typename U>
  std::vector<ModInt> convolution(const std::vector<U>& a,
                                  const std::vector<U>& b) {
    const int a_size = a.size(), b_size = b.size();
    const int c_size = a_size + b_size - 1;
    int lg = 1;
    while ((1 << lg) < c_size) ++lg;
    const int n = 1 << lg;
    std::vector<ModInt> c(n, 0), d(n, 0);
    std::copy(a.begin(), a.end(), c.begin());
    calc(&c);
    std::copy(b.begin(), b.end(), d.begin());
    calc(&d);
    for (int i = 0; i < n; ++i) {
      c[i] *= d[i];
    }
    idft(&c);
    c.resize(c_size);
    return c;
  }

 private:
  const int primes[23][3]{
    {16957441, 329, 14},
    {17006593, 26, 15},
    {19529729, 770, 17},
    {167772161, 3, 25},
    {469762049, 3, 26},
    {645922817, 3, 23},
    {897581057, 3, 23},
    {924844033, 5, 21},
    {935329793, 3, 22},
    {943718401, 7, 22},
    {950009857, 7, 21},
    {962592769, 7, 21},
    {975175681, 17, 21},
    {976224257, 3, 20},
    {985661441, 3, 22},
    {998244353, 3, 23},
    {1004535809, 3, 21},
    {1007681537, 3, 20},
    {1012924417, 5, 21},
    {1045430273, 3, 20},
    {1051721729, 6, 20},
    {1053818881, 7, 20},
    {1224736769, 3, 24}
  };

  int n_max;
  ModInt root;
  std::vector<int> butterfly{0};
  std::vector<std::vector<ModInt>> omega{{1}};

  void calc(std::vector<ModInt>* a) {
    const int n = a->size(), prev_n = butterfly.size();
    if (n > prev_n) {
      assert(n <= n_max);
      butterfly.resize(n);
      const int prev_lg = omega.size(), lg = __builtin_ctz(n);
      for (int i = 1; i < prev_n; ++i) {
        butterfly[i] <<= lg - prev_lg;
      }
      for (int i = prev_n; i < n; ++i) {
        butterfly[i] = (butterfly[i >> 1] >> 1) | ((i & 1) << (lg - 1));
      }
      omega.resize(lg);
      for (int i = prev_lg; i < lg; ++i) {
        omega[i].resize(1 << i);
        const ModInt tmp = root.pow((ModInt::get_mod() - 1) >> (i + 1));
        for (int j = 0; j < (1 << (i - 1)); ++j) {
          omega[i][j << 1] = omega[i - 1][j];
          omega[i][(j << 1) + 1] = omega[i - 1][j] * tmp;
        }
      }
    }
    const int shift = __builtin_ctz(butterfly.size()) - __builtin_ctz(n);
    for (int i = 0; i < n; ++i) {
      const int j = butterfly[i] >> shift;
      if (i < j) std::swap((*a)[i], (*a)[j]);
    }
    for (int block = 1, den = 0; block < n; block <<= 1, ++den) {
      for (int i = 0; i < n; i += (block << 1)) {
        for (int j = 0; j < block; ++j) {
          const ModInt tmp = (*a)[i + j + block] * omega[den][j];
          (*a)[i + j + block] = (*a)[i + j] - tmp;
          (*a)[i + j] += tmp;
        }
      }
    }
  }
};

template <typename T>
struct FormalPowerSeries {
  std::vector<T> coef;

  explicit FormalPowerSeries(const int deg = 0) : coef(deg + 1, 0) {}
  explicit FormalPowerSeries(const std::vector<T>& coef) : coef(coef) {}
  FormalPowerSeries(const std::initializer_list<T> init)
      : coef(init.begin(), init.end()) {}
  template <typename InputIter>
  explicit FormalPowerSeries(const InputIter first, const InputIter last)
      : coef(first, last) {}

  inline const T& operator[](const int term) const { return coef[term]; }
  inline T& operator[](const int term) { return coef[term]; }

  using MULT = std::function<std::vector<T>(const std::vector<T>&,
                                            const std::vector<T>&)>;
  using SQRT = std::function<bool(const T&, T*)>;
  static void set_mult(const MULT mult) { get_mult() = mult; }
  static void set_sqrt(const SQRT sqrt) { get_sqrt() = sqrt; }

  void resize(const int deg) { coef.resize(deg + 1, 0); }
  void shrink() {
    while (coef.size() > 1 && coef.back() == 0) coef.pop_back();
  }
  int degree() const { return static_cast<int>(coef.size()) - 1; }

  FormalPowerSeries& operator=(const std::vector<T>& coef_) {
    coef = coef_;
    return *this;
  }
  FormalPowerSeries& operator=(const FormalPowerSeries& x) = default;

  FormalPowerSeries& operator+=(const FormalPowerSeries& x) {
    const int deg_x = x.degree();
    if (deg_x > degree()) resize(deg_x);
    for (int i = 0; i <= deg_x; ++i) {
      coef[i] += x[i];
    }
    return *this;
  }
  FormalPowerSeries& operator-=(const FormalPowerSeries& x) {
    const int deg_x = x.degree();
    if (deg_x > degree()) resize(deg_x);
    for (int i = 0; i <= deg_x; ++i) {
      coef[i] -= x[i];
    }
    return *this;
  }
  FormalPowerSeries& operator*=(const T x) {
    for (T& e : coef) e *= x;
    return *this;
  }
  FormalPowerSeries& operator*=(const FormalPowerSeries& x) {
    return *this = get_mult()(coef, x.coef);
  }
  FormalPowerSeries& operator/=(const T x) {
    assert(x != 0);
    return *this *= static_cast<T>(1) / x;
  }
  FormalPowerSeries& operator/=(const FormalPowerSeries& x) {
    const int n = degree() - x.degree() + 1;
    if (n <= 0) return *this = FormalPowerSeries();
    const std::vector<T> tmp = get_mult()(
        std::vector<T>(coef.rbegin(), std::next(coef.rbegin(), n)),
        FormalPowerSeries(
            x.coef.rbegin(),
            std::next(x.coef.rbegin(), std::min(x.degree() + 1, n)))
        .inv(n - 1).coef);
    return *this = FormalPowerSeries(std::prev(tmp.rend(), n), tmp.rend());
  }
  FormalPowerSeries& operator%=(const FormalPowerSeries& x) {
    if (x.degree() == 0) return *this = FormalPowerSeries{0};
    *this -= *this / x * x;
    resize(x.degree() - 1);
    return *this;
  }
  FormalPowerSeries& operator<<=(const int n) {
    coef.insert(coef.begin(), n, 0);
    return *this;
  }
  FormalPowerSeries& operator>>=(const int n) {
    if (degree() < n) return *this = FormalPowerSeries();
    coef.erase(coef.begin(), coef.begin() + n);
    return *this;
  }

  bool operator==(FormalPowerSeries x) const {
    x.shrink();
    FormalPowerSeries y = *this;
    y.shrink();
    return x.coef == y.coef;
  }
  bool operator!=(const FormalPowerSeries& x) const { return !(*this == x); }

  FormalPowerSeries operator+() const { return *this; }
  FormalPowerSeries operator-() const {
    FormalPowerSeries res = *this;
    for (T& e : res.coef) e = -e;
    return res;
  }

  FormalPowerSeries operator+(const FormalPowerSeries& x) const {
    return FormalPowerSeries(*this) += x;
  }
  FormalPowerSeries operator-(const FormalPowerSeries& x) const {
    return FormalPowerSeries(*this) -= x;
  }
  FormalPowerSeries operator*(const T x) const {
    return FormalPowerSeries(*this) *= x;
  }
  FormalPowerSeries operator*(const FormalPowerSeries& x) const {
    return FormalPowerSeries(*this) *= x;
  }
  FormalPowerSeries operator/(const T x) const {
    return FormalPowerSeries(*this) /= x;
  }
  FormalPowerSeries operator/(const FormalPowerSeries& x) const {
    return FormalPowerSeries(*this) /= x;
  }
  FormalPowerSeries operator%(const FormalPowerSeries& x) const {
    return FormalPowerSeries(*this) %= x;
  }
  FormalPowerSeries operator<<(const int n) const {
    return FormalPowerSeries(*this) <<= n;
  }
  FormalPowerSeries operator>>(const int n) const {
    return FormalPowerSeries(*this) >>= n;
  }

  T horner(const T x) const {
    T res = 0;
    for (int i = degree(); i >= 0; --i) {
      res = res * x + coef[i];
    }
    return res;
  }

  FormalPowerSeries differential() const {
    const int deg = degree();
    assert(deg >= 0);
    FormalPowerSeries res(std::max(deg - 1, 0));
    for (int i = 1; i <= deg; ++i) {
      res[i - 1] = coef[i] * i;
    }
    return res;
  }

  FormalPowerSeries exp(int deg = -1) const {
    assert(coef[0] == 0);
    const int n = coef.size();
    if (deg == -1) deg = n - 1;
    const FormalPowerSeries one{1};
    FormalPowerSeries res = one;
    for (int i = 1; i <= deg; i <<= 1) {
      res *= FormalPowerSeries(coef.begin(),
                               std::next(coef.begin(), std::min(n, i << 1)))
             - res.log((i << 1) - 1) + one;
      res.coef.resize(i << 1);
    }
    res.resize(deg);
    return res;
  }

  FormalPowerSeries inv(int deg = -1) const {
    assert(coef[0] != 0);
    const int n = coef.size();
    if (deg == -1) deg = n - 1;
    FormalPowerSeries res{static_cast<T>(1) / coef[0]};
    for (int i = 1; i <= deg; i <<= 1) {
      res = res + res - res * res * FormalPowerSeries(
          coef.begin(), std::next(coef.begin(), std::min(n, i << 1)));
      res.coef.resize(i << 1);
    }
    res.resize(deg);
    return res;
  }

  FormalPowerSeries log(int deg = -1) const {
    assert(coef[0] == 1);
    if (deg == -1) deg = degree();
    FormalPowerSeries integrand = differential() * inv(deg - 1);
    integrand.resize(deg);
    for (int i = deg; i > 0; --i) {
      integrand[i] = integrand[i - 1] / i;
    }
    integrand[0] = 0;
    return integrand;
  }

  FormalPowerSeries pow(long long exponent, int deg = -1) const {
    const int n = coef.size();
    if (deg == -1) deg = n - 1;
    for (int i = 0; i < n; ++i) {
      if (coef[i] == 0) continue;
      const long long shift = exponent * i;
      if (shift > deg) break;
      T tmp = 1, base = coef[i];
      for (long long e = exponent; e > 0; e >>= 1) {
        if (e & 1) tmp *= base;
        base *= base;
      }
      const FormalPowerSeries res = ((*this >> i) / coef[i]).log(deg - shift);
      return ((res * exponent).exp(deg - shift) * tmp) << shift;
    }
    return FormalPowerSeries(deg);
  }

  FormalPowerSeries mod_pow(long long exponent,
                            const FormalPowerSeries& md) const {
    const int deg = md.degree() - 1;
    if (deg < 0) return FormalPowerSeries(-1);
    const FormalPowerSeries inv_rev_md =
        FormalPowerSeries(md.coef.rbegin(), md.coef.rend()).inv();
    const auto mod_mult = [&md, &inv_rev_md, deg](
        FormalPowerSeries* multiplicand, const FormalPowerSeries& multiplier)
        -> void {
      *multiplicand *= multiplier;
      if (deg < multiplicand->degree()) {
        const int n = multiplicand->degree() - deg;
        const FormalPowerSeries quotient =
            FormalPowerSeries(multiplicand->coef.rbegin(),
                              std::next(multiplicand->coef.rbegin(), n))
            * FormalPowerSeries(
                  inv_rev_md.coef.begin(),
                  std::next(inv_rev_md.coef.begin(), std::min(deg + 2, n)));
        *multiplicand -=
            FormalPowerSeries(std::prev(quotient.coef.rend(), n),
                              quotient.coef.rend()) * md;
        multiplicand->resize(deg);
      }
      multiplicand->shrink();
    };
    FormalPowerSeries res{1}, base = *this;
    for (; exponent > 0; exponent >>= 1) {
      if (exponent & 1) mod_mult(&res, base);
      mod_mult(&base, base);
    }
    return res;
  }

  FormalPowerSeries sqrt(int deg = -1) const {
    const int n = coef.size();
    if (deg == -1) deg = n - 1;
    if (coef[0] == 0) {
      for (int i = 1; i < n; ++i) {
        if (coef[i] == 0) continue;
        if (i & 1) return FormalPowerSeries(-1);
        const int shift = i >> 1;
        if (deg < shift) break;
        FormalPowerSeries res = (*this >> i).sqrt(deg - shift);
        if (res.coef.empty()) return FormalPowerSeries(-1);
        res <<= shift;
        res.resize(deg);
        return res;
      }
      return FormalPowerSeries(deg);
    }
    T s;
    if (!get_sqrt()(coef.front(), &s)) return FormalPowerSeries(-1);
    FormalPowerSeries res{s};
    const T half = static_cast<T>(1) / 2;
    for (int i = 1; i <= deg; i <<= 1) {
      res = (FormalPowerSeries(coef.begin(),
                               std::next(coef.begin(), std::min(n, i << 1)))
             * res.inv((i << 1) - 1) + res) * half;
    }
    res.resize(deg);
    return res;
  }

  FormalPowerSeries translate(const T c) const {
    const int n = coef.size();
    std::vector<T> fact(n, 1), inv_fact(n, 1);
    for (int i = 1; i < n; ++i) {
      fact[i] = fact[i - 1] * i;
    }
    inv_fact[n - 1] = static_cast<T>(1) / fact[n - 1];
    for (int i = n - 1; i > 0; --i) {
      inv_fact[i - 1] = inv_fact[i] * i;
    }
    std::vector<T> g(n), ex(n);
    for (int i = 0; i < n; ++i) {
      g[i] = coef[i] * fact[i];
    }
    std::reverse(g.begin(), g.end());
    T pow_c = 1;
    for (int i = 0; i < n; ++i) {
      ex[i] = pow_c * inv_fact[i];
      pow_c *= c;
    }
    const std::vector<T> conv = get_mult()(g, ex);
    FormalPowerSeries res(n - 1);
    for (int i = 0; i < n; ++i) {
      res[i] = conv[n - 1 - i] * inv_fact[i];
    }
    return res;
  }

 private:
  static MULT& get_mult() {
    static MULT mult = [](const std::vector<T>& a, const std::vector<T>& b)
        -> std::vector<T> {
      const int n = a.size(), m = b.size();
      std::vector<T> res(n + m - 1, 0);
      for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
          res[i + j] += a[i] * b[j];
        }
      }
      return res;
    };
    return mult;
  }
  static SQRT& get_sqrt() {
    static SQRT sqrt = [](const T& a, T* res) -> bool { return false; };
    return sqrt;
  }
};

template <template <typename> class C, typename T>
struct MultipointEvaluation {
  std::vector<T> f_x;
  std::vector<C<T>> subproduct_tree;

  explicit MultipointEvaluation(const std::vector<T> &xs)
      : n(xs.size()), f_x(xs.size()), subproduct_tree(xs.size() << 1) {
    for (int i = 0; i < n; ++i) {
      subproduct_tree[i + n] = C<T>{-xs[i], 1};
    }
    for (int i = n - 1; i > 0; --i) {
      subproduct_tree[i] =
          subproduct_tree[i << 1] * subproduct_tree[(i << 1) + 1];
    }
  }

  void build(const C<T>& f) { dfs(f, 1); }

 private:
  const int n;

  void dfs(C<T> f, int node) {
    f %= subproduct_tree[node];
    if (node < n) {
      dfs(f, node << 1);
      dfs(f, (node << 1) + 1);
    } else {
      f_x[node - n] = f[0];
    }
  }
};

int main() {
  FormalPowerSeries<ModInt>::set_mult([](const vector<ModInt>& a, const vector<ModInt>& b) -> vector<ModInt> {
    static NumberTheoreticTransform<MOD> ntt;
    return ntt.convolution(a, b);
  });
  int n, s; cin >> n >> s;
  vector<ModInt> p(n);
  REP(i, n) {
    cin >> p[i];
    p[i] /= s;
  }
  vector<ModInt> cs(n);
  REP(i, n) cs[i] = -ModInt::inv(p[i].v);
  FormalPowerSeries<ModInt> f = MultipointEvaluation<FormalPowerSeries, ModInt>(cs).subproduct_tree[1];
  assert(f.degree() == n);
  ModInt c = 1;
  REP(i, n) c *= p[i];
  f *= c;
  REP(i, n + 1) f[i] *= ModInt::fact(i);
  REP(i, n) f[i + 1] += f[i];
  ModInt ans = 0;
  REP(i, n) {
    ans += p[i] * p[i] * (f / FormalPowerSeries<ModInt>{1, p[i]})[n - 1];
  }
  cout << ans << '\n';
  return 0;
}
0