oj.uz

Submission #969439

# Submission time Handle Problem Language Result Execution time Memory
969439 2024-04-25T07:06:45 Z kilkuwu Boat (APIO16_boat) C++17
9 / 100
 228 ms 6484 KB 
#include <bits/stdc++.h>

#define nl '\n'

#ifdef LOCAL
#include "template/debug.hpp"
#else
#define dbg(...) ;
#define timer(...) ;
#endif

template <int md>
struct Modular {
  int v;

  constexpr Modular() : v(0) {}

  template <typename T>
  static inline int normalize(const T& x) {
    int res = -md <= x && x < md ? static_cast<int>(x) : static_cast<int>(x % md);
    return res + (res < 0) * md;
  }
  
  static constexpr int mod() {
    return md;
  }

  template <typename U>
  Modular(const U& x) : v(normalize(x)) {}

  const int& operator()() const { return v; }

  template <typename U>
  explicit operator U() const {
    return static_cast<U>(v);
  }

  using M = Modular;

  constexpr static inline M _raw(int x) {
    static_assert(x >= 0 && x < md);
    M res;
    res.v = x;
    return res;
  }

  template <typename U>
  friend std::enable_if_t<std::is_integral_v<U>, M> power(M b, U e) {
    assert(e >= 0);
    M ans = 1;
    while (e) {
      if (e & 1) ans *= b;
      b *= b;
      e >>= 1;
    }
    return ans;
  }

  M inv() const {
    M res = power(*this, md - 2);
    return res;
  }

  M& operator+=(const M& y) { return v += y.v, v -= (v >= md) * md, *this; }
  M& operator-=(const M& y) { return v -= y.v, v += (v < 0) * md, *this; }
  M& operator*=(const M& y) { return v = (int64_t) v * y.v % md, *this; }
  M& operator/=(const M& y) { return *this *= y.inv(); }

  M& operator++() { return *this += _raw(1); }
  M& operator--() { return *this -= _raw(1); }

  M operator++(int) {
    M res(*this);
    return *this += _raw(1), res;
  }

  M operator--(int) {
    M res(*this);
    return *this -= _raw(1), res;
  }

  M operator-() const { return M(-v); }

  friend bool operator==(const M& x, const M& y) { return x.v == y.v; }
  friend bool operator<(const M& x, const M& y) { return x.v < y.v; }
  friend bool operator>(const M& x, const M& y) { return x.v > y.v; }
  friend bool operator<=(const M& x, const M& y) { return x.v <= y.v; }
  friend bool operator>=(const M& x, const M& y) { return x.v >= y.v; }
  friend bool operator!=(const M& x, const M& y) { return x.v != y.v; }

  template <typename Istream>
  friend Istream& operator>>(Istream& is, M& y) {
    int64_t x;
    is >> x;
    y.v = y.normalize(x);
    return is;
  }

  template <typename Ostream>
  friend Ostream& operator<<(Ostream& os, const M& y) {
    return os << y.v;
  }

  friend M operator+(const M& x, const M& y) { return M(x) += y; }
  friend M operator-(const M& x, const M& y) { return M(x) -= y; }
  friend M operator*(const M& x, const M& y) { return M(x) *= y; }
  friend M operator/(const M& x, const M& y) { return M(x) /= y; }
};

constexpr int md = 1e9 + 7;
using Mint = Modular<md>;

signed main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  
  int n;
  std::cin >> n;
  std::vector<int> a(n), b(n);
  for (int i = 0; i < n; i++) std::cin >> a[i] >> b[i], b[i]++;

  std::vector<int> vals(a.begin(), a.end());
  vals.insert(vals.end(), b.begin(), b.end());
  std::sort(vals.begin(), vals.end());
  vals.erase(std::unique(vals.begin(), vals.end()), vals.end());
  dbg(vals);

  int num_segments = vals.size() - 1;

  for (int i = 0; i < n; i++) {
    a[i] = std::lower_bound(vals.begin(), vals.end(), a[i]) - vals.begin();
    b[i] = std::lower_bound(vals.begin(), vals.end(), b[i]) - vals.begin();
    dbg(a[i], b[i]);
  }

  std::vector<std::vector<Mint>> prepared(num_segments, std::vector<Mint>(n + 1));

  for (int i = 0; i < num_segments; i++) {
    int len = vals[i + 1] - vals[i] - 1;
    prepared[i][0] = 1;
    for (int j = 0; j < n; j++) {
      prepared[i][j + 1] = prepared[i][j] * (len - j) / (j + 1);
    }
    for (int j = 0; j < n; j++) {
      prepared[i][j + 1] += prepared[i][j];
    }
  }


  std::vector<std::vector<Mint>> dp(n + 1, std::vector<Mint>(num_segments + 1));
  std::vector<std::vector<Mint>> ff(n + 1, std::vector<Mint>(num_segments + 1));


  dp[n].back() = 1;
  for (int j = 0; j <= num_segments; j++) {
    ff[n][j] = 1;
  }

  Mint ans = 0;

  for (int i = n - 1; i >= 0; i--) {
    for (int j = num_segments - 1; j >= 0; j--) {
      if (a[i] <= j && j < b[i]) {
        int cnt = 0;
        for (int k = i; k < n; k++) {
          cnt += a[k] <= j && j < b[k];
          int rem = cnt - 1;
          Mint mul = prepared[j][rem];

          dbg(i, j, k, mul, rem, ff[k + 1][j + 1], mul * ff[k + 1][j + 1]);
          dp[i][j] += ff[k + 1][j + 1] * mul;
        }
      }
      ans += dp[i][j];
      dbg(i, j, dp[i][j]);
      ff[i][j] = ff[i][j + 1] + dp[i][j];
    }
  }

  std::cout << ans << nl;
  // 4 
  // 4 7 
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 78 ms 6276 KB Output is correct
2 Correct 79 ms 6272 KB Output is correct
3 Correct 78 ms 6228 KB Output is correct
4 Correct 78 ms 6276 KB Output is correct
5 Correct 78 ms 6224 KB Output is correct
6 Correct 78 ms 6292 KB Output is correct
7 Correct 77 ms 6224 KB Output is correct
8 Correct 79 ms 6292 KB Output is correct
9 Correct 78 ms 6484 KB Output is correct
10 Correct 78 ms 6228 KB Output is correct
11 Correct 79 ms 6272 KB Output is correct
12 Correct 78 ms 6228 KB Output is correct
13 Correct 78 ms 6284 KB Output is correct
14 Correct 78 ms 6296 KB Output is correct
15 Correct 77 ms 6288 KB Output is correct
16 Correct 15 ms 1332 KB Output is correct
17 Correct 16 ms 1616 KB Output is correct
18 Correct 15 ms 1372 KB Output is correct
19 Correct 16 ms 1608 KB Output is correct
20 Correct 15 ms 1372 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 78 ms 6276 KB Output is correct
2 Correct 79 ms 6272 KB Output is correct
3 Correct 78 ms 6228 KB Output is correct
4 Correct 78 ms 6276 KB Output is correct
5 Correct 78 ms 6224 KB Output is correct
6 Correct 78 ms 6292 KB Output is correct
7 Correct 77 ms 6224 KB Output is correct
8 Correct 79 ms 6292 KB Output is correct
9 Correct 78 ms 6484 KB Output is correct
10 Correct 78 ms 6228 KB Output is correct
11 Correct 79 ms 6272 KB Output is correct
12 Correct 78 ms 6228 KB Output is correct
13 Correct 78 ms 6284 KB Output is correct
14 Correct 78 ms 6296 KB Output is correct
15 Correct 77 ms 6288 KB Output is correct
16 Correct 15 ms 1332 KB Output is correct
17 Correct 16 ms 1616 KB Output is correct
18 Correct 15 ms 1372 KB Output is correct
19 Correct 16 ms 1608 KB Output is correct
20 Correct 15 ms 1372 KB Output is correct
21 Incorrect 228 ms 5880 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 5 ms 604 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 78 ms 6276 KB Output is correct
2 Correct 79 ms 6272 KB Output is correct
3 Correct 78 ms 6228 KB Output is correct
4 Correct 78 ms 6276 KB Output is correct
5 Correct 78 ms 6224 KB Output is correct
6 Correct 78 ms 6292 KB Output is correct
7 Correct 77 ms 6224 KB Output is correct
8 Correct 79 ms 6292 KB Output is correct
9 Correct 78 ms 6484 KB Output is correct
10 Correct 78 ms 6228 KB Output is correct
11 Correct 79 ms 6272 KB Output is correct
12 Correct 78 ms 6228 KB Output is correct
13 Correct 78 ms 6284 KB Output is correct
14 Correct 78 ms 6296 KB Output is correct
15 Correct 77 ms 6288 KB Output is correct
16 Correct 15 ms 1332 KB Output is correct
17 Correct 16 ms 1616 KB Output is correct
18 Correct 15 ms 1372 KB Output is correct
19 Correct 16 ms 1608 KB Output is correct
20 Correct 15 ms 1372 KB Output is correct
21 Incorrect 228 ms 5880 KB Output isn't correct
22 Halted 0 ms 0 KB -