結果

問題 No.1474 かさまＪ
ユーザー m_tsubasa
提出日時 2021-04-09 22:28:50
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 508 ms / 2,500 ms
コード長 4,445 bytes
コンパイル時間 3,003 ms
コンパイル使用メモリ 208,840 KB
最終ジャッジ日時 2025-01-20 14:46:55
ジャッジサーバーID
（参考情報） 		judge5 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 4
other AC * 17
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 #
プレゼンテーションモードにする

#include <bits/stdc++.h>
using namespace std;
template <int mod = (int)(1e9 + 7)>
struct ModInt {
  int x;
  ModInt() : x(0) {}
  ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
  ModInt &operator+=(const ModInt &p) {
    if ((x += p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator-=(const ModInt &p) {
    if ((x += mod - p.x) >= mod) x -= mod;
    return *this;
  }
  ModInt &operator*=(const ModInt &p) {
    x = (int)(1LL * x * p.x % mod);
    return *this;
  }
  ModInt &operator/=(const ModInt &p) {
    *this *= p.inverse();
    return *this;
  }
  ModInt operator-() const { return ModInt(-x); }
  ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
  ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
  ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
  ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
  bool operator==(const ModInt &p) const { return x == p.x; }
  bool operator!=(const ModInt &p) const { return x != p.x; }
  ModInt inverse() const {
    int a = x, b = mod, u = 1, v = 0, t;
    while (b > 0) {
      t = a / b;
      swap(a -= t * b, b);
      swap(u -= t * v, v);
    }
    return ModInt(u);
  }
  ModInt pow(int64_t n) const {
    ModInt res(1), mul(x);
    while (n) {
      if (n & 1) res *= mul;
      mul *= mul;
      n >>= 1;
    }
    return res;
  }
  friend ostream &operator<<(ostream &os, const ModInt &p) { return os << p.x; }
  friend istream &operator>>(istream &is, ModInt &a) {
    int64_t t;
    is >> t;
    a = ModInt<mod>(t);
    return (is);
  }
  static int get_mod() { return mod; }
};
struct Combination {
  vector<ModInt<>> _fact, _rfact, _inv;
  Combination(long long nsize = 5000000)
      : _fact(nsize + 1), _rfact(nsize + 1), _inv(nsize + 1) {
    _fact[0] = _rfact[nsize] = _inv[0] = 1;
    for (int i = 1; i <= nsize; i++) _fact[i] = _fact[i - 1] * i;
    _rfact[nsize] /= _fact[nsize];
    for (int i = nsize - 1; i >= 0; i--) _rfact[i] = _rfact[i + 1] * (i + 1);
    for (int i = 1; i <= nsize; i++) _inv[i] = _rfact[i] * _fact[i - 1];
  }
  inline ModInt<> fact(int k) const { return _fact[k]; }
  inline ModInt<> rfact(int k) const { return _rfact[k]; }
  inline ModInt<> inv(int k) const { return _inv[k]; }
  ModInt<> P(int n, int r) const {
    if (r < 0 || n < r) return 0;
    return fact(n) * rfact(n - r);
  }
  ModInt<> C(int p, int q) const {
    if (q < 0 || p < q) return 0;
    return fact(p) * rfact(q) * rfact(p - q);
  }
  ModInt<> largeC(long long p, long long q) const {
    if (q < 0 || p < q) return 0;
    if (q >= (long long)_fact.size()) q = p - q;
    // if (q >= (long long)5000) q = p - q;
    ModInt<> res = rfact(q);
    for (int i = 0; i < q; ++i) res *= p - i;
    return res;
  }
  // n types,choose r
  ModInt<> H(int n, int r) const {
    if (n < 0 || r < 0) return (0);
    return r == 0 ? 1 : C(n + r - 1, r);
  }
  ModInt<> largeH(long long n, long long r) const {
    if (n < 0 || r < 0) return (0);
    return r == 0 ? 1 : largeC(n + r - 1, r);
  }
  ModInt<> Catalan(int n) {
    // C(2n,n) / (n + 1)
    return fact(2 * n) * rfact(n + 1) * rfact(n);
  }
};
using mint = ModInt<>;
int n, x, y, l;
vector<int> s;
vector<vector<vector<mint>>> dp, sum;
mint solve();
int main() {
  cin >> n >> x >> y >> l;
  s.resize(n);
  for (auto &p : s) cin >> p;
  cout << solve() << endl;
  return 0;
}
mint solve() {
  dp.assign(n + 1, vector(n + 1, vector<mint>(y + 1, 0)));
  sum.assign(n + 1, vector(n + 1, vector<mint>(y + 1, 0)));
  dp[0][0][0] = 1;
  for (int i = 0; i <= y; ++i) sum[0][0][i] = 1;
  auto calc = [](int i, int j, int lef, int righ) {
    mint res = 0;
    lef = max(0, lef);
    righ = max(0, righ);
    if (righ >= 0) res = sum[i][j][righ];
    if (lef > 0) res -= sum[i][j][lef - 1];
    return res;
  };
  for (int i = 0; i < n; ++i) {
    dp[i + 1] = dp[i];
    for (int j = 1; j <= n; ++j) {
      for (int k = 1; k <= y; ++k)
        dp[i + 1][j][k] += calc(i, j - 1, k - s[i], k - 1);
    }
    for (int j = 0; j <= n; ++j)
      for (int k = 0; k <= y; ++k) {
        sum[i + 1][j][k] = dp[i + 1][j][k];
        if (k) sum[i + 1][j][k] += sum[i + 1][j][k - 1];
      }
  }
  mint res = 0;
  Combination com;
  for (int i = 0; i <= n; ++i)
    for (int j = 0; j <= y; ++j)
      if (0 <= i * l - j && i * l - j <= x)
        res += dp[n][i][j] * com.H(n, x - (i * l - j));
  return res;
}
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