oj.uz

Submission #801683

# Submission time Handle Problem Language Result Execution time Memory
801683 2023-08-02T07:12:57 Z peijar Boat (APIO16_boat) C++17
0 / 100
 14 ms 1236 KB 
#include <bits/stdc++.h>
#define int long long
using namespace std;

string to_string(string s) { return s; }
template <typename T> string to_string(T v) {
  bool first = true;
  string res = "[";
  for (const auto &x : v) {
    if (!first)
      res += ", ";
    first = false;
    res += to_string(x);
  }
  res += "]";
  return res;
}

void dbg_out() { cout << endl; }
template <typename Head, typename... Tail> void dbg_out(Head H, Tail... T) {
  cout << ' ' << to_string(H);
  dbg_out(T...);
}

#ifdef DEBUG
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif

template <const int32_t MOD> struct ModInt {
  int32_t x;
  ModInt() : x(0) {}
  ModInt(long long u) : x(u % MOD) {
    if (x < 0)
      x += MOD;
  }
  friend bool operator==(const ModInt &a, const ModInt &b) {
    return a.x == b.x;
  }
  friend bool operator!=(const ModInt &a, const ModInt &b) {
    return a.x != b.x;
  }
  friend bool operator<(const ModInt &a, const ModInt &b) { return a.x < b.x; }
  friend bool operator>(const ModInt &a, const ModInt &b) { return a.x > b.x; }
  friend bool operator<=(const ModInt &a, const ModInt &b) {
    return a.x <= b.x;
  }
  friend bool operator>=(const ModInt &a, const ModInt &b) {
    return a.x >= b.x;
  }
  static ModInt sign(long long k) {
    return ((k & 1) ? ModInt(MOD - 1) : ModInt(1));
  }

  ModInt &operator+=(const ModInt &m) {
    x += m.x;
    if (x >= MOD)
      x -= MOD;
    return *this;
  }
  ModInt &operator-=(const ModInt &m) {
    x -= m.x;
    if (x < 0LL)
      x += MOD;
    return *this;
  }
  ModInt &operator*=(const ModInt &m) {
    x = (1LL * x * m.x) % MOD;
    return *this;
  }

  friend ModInt operator-(const ModInt &a) {
    ModInt res(a);
    if (res.x)
      res.x = MOD - res.x;
    return res;
  }
  friend ModInt operator+(const ModInt &a, const ModInt &b) {
    return ModInt(a) += ModInt(b);
  }
  friend ModInt operator-(const ModInt &a, const ModInt &b) {
    return ModInt(a) -= ModInt(b);
  }
  friend ModInt operator*(const ModInt &a, const ModInt &b) {
    return ModInt(a) *= ModInt(b);
  }

  static long long fp(long long u, long long k) {
    long long res = 1LL;
    while (k > 0LL) {
      if (k & 1LL)
        res = (res * u) % MOD;
      u = (u * u) % MOD;
      k /= 2LL;
    }
    return res;
  }

  static constexpr int mod() { return MOD; }

  ModInt fastpow(long long k) { return ModInt(fp(x, k)); }
  ModInt inv() {
    assert(x);
    return ModInt(fp(x, MOD - 2));
  }
  ModInt &operator/=(const ModInt &m) { return *this *= ModInt(m).inv(); }
  friend ModInt operator/(const ModInt &a, const ModInt &b) {
    return ModInt(a) *= ModInt(b).inv();
  }

  friend ostream &operator<<(ostream &out, const ModInt &a) {
    return out << a.x;
  }
  friend istream &operator>>(istream &in, ModInt &a) { return in >> a.x; }
  friend string to_string(ModInt u) { return to_string(u.x); }
};

const int MOD = 1e9 + 7;
using Mint = ModInt<MOD>;

const int MAXN = 1e5;
Mint fact[MAXN], invFact[MAXN];

void initFact() {
  fact[0] = 1;
  for (int i = 1; i < MAXN; ++i)
    fact[i] = i * fact[i - 1];
  invFact[MAXN - 1] = fact[MAXN - 1].inv();
  for (int i = MAXN - 1; i; --i)
    invFact[i - 1] = invFact[i] * i;
}

map<pair<int, int>, Mint> cache;

Mint binom(int n, int k) {
  if (k < 0 or k > n)
    return 0;
  if (cache.count({n, k}))
    return cache[{n, k}];

  Mint ret = 1;
  for (int i = n; i > n - k; --i)
    ret *= i;
  ret *= invFact[k];
  return cache[{n, k}] = ret;
}

signed main(void) {
  ios_base::sync_with_stdio(false);
  cin.tie(0);

  initFact();

  int nbEcoles;
  cin >> nbEcoles;

  map<int, vector<int>> events;

  for (int iEcole = 0; iEcole < nbEcoles; ++iEcole) {
    int lo, up;
    cin >> lo >> up;
    events[lo].push_back(iEcole);
    events[1 + up].push_back(iEcole);
  }
  vector<Mint> dp(nbEcoles);
  set<int> on;
  int prev = 0;
  for (auto [timeStamp, toUpdate] : events) {
    for (int x : toUpdate) {
      if (on.count(x))
        on.erase(x);
      else
        on.insert(x);
    }
    int lo = prev + 1, up = timeStamp;
    vector<int> vec(on.begin(), on.end());
    vector<Mint> nxtDp(on.size());
    for (int fst = 0; fst < (int)on.size(); ++fst)
      for (int lst = fst; lst < (int)on.size(); ++lst) {
        int middle = max(0LL, fst - lst - 1);
        for (int takeMiddle = 0; takeMiddle <= middle; ++takeMiddle) {
          Mint choixEcoles = binom(middle, takeMiddle);
          Mint choixCnt = binom(up - lo + 1, takeMiddle + 1 + (fst != lst));
          Mint choixAvant =
              1 + accumulate(dp.begin(), dp.begin() + vec[fst], Mint(0));
          nxtDp[lst] += choixEcoles * choixCnt * choixAvant;
        }
      }
    for (int i = 0; i < (int)on.size(); ++i)
      dp[vec[i]] += nxtDp[i];
    prev = up;
  }
  cout << accumulate(dp.begin(), dp.end(), Mint(0)) << endl;
}

Subtask #1
0 / 9.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 1236 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 1236 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 14 ms 1112 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 1236 KB Output isn't correct
2 Halted 0 ms 0 KB -