Submission #967918

#	Time	Username	Problem	Language	Result	Execution time	Memory
967918		duckindog	Boat (APIO16_boat)	C++17	9 / 100	2031 ms	524288 KiB

boat

#include <bits/stdc++.h>

using namespace std;

const int N = 500 + 10,
          M = 1'000'000'007;
int n;
int a[N], b[N];

struct modint {
  int value;

  modint(int value = 0) : value(value) {}

  modint operator + (modint rhs) { return (rhs.value + value) % M; }
  modint operator - (modint rhs) { return (value - rhs.value + M) % M; }
  modint operator * (modint rhs) { return 1ll * value * rhs.value % M; }

  modint operator += (modint rhs) { value = (value + rhs.value) % M; return *this; }
  modint operator -= (modint rhs) { value = (value - rhs.value + M) % M; return *this; }
  modint operator *= (modint rhs) { value = 1ll * value * rhs.value % M; return *this; }

  friend ostream& operator << (ostream& os, modint rhs) {
    return os << rhs.value;
  }
};

modint f[2][1'000'010];

int32_t main() { 
  cin.tie(0)->sync_with_stdio(0);

  cin >> n;
  for (int i = 1; i <= n; ++i) cin >> a[i] >> b[i];

  vector<int> rrh;
  for (int i = 1; i <= n; ++i) {
    for (int j = a[i]; j <= b[i]; ++j) rrh.push_back(j);
  }

  sort(rrh.begin(), rrh.end());
  rrh.resize(unique(rrh.begin(), rrh.end()) - rrh.begin());

  f[0][0] = 1;

  for (int i = 1; i <= n; ++i) { 
    int id = i & 1, p = id ^ 1;
    for (int j = 0; j <= rrh.size(); ++j) f[id][j] = 0;
    
    int it = lower_bound(rrh.begin(), rrh.end(), a[i]) - rrh.begin() + 1;
    
    for (int j = 0; j <= rrh.size(); ++j) f[id][j] = f[p][j];
    for (int j = it; j <= b[i] - a[i] + it; ++j) { 
      for (int t = 0; t < j; ++t) f[id][j] += f[p][t];
    }
  }

  modint answer = 0;
  for (int i = 1; i <= rrh.size(); ++i) answer += f[n & 1][i];
  
  cout << answer << "\n";
}

Compilation message (stderr)

boat.cpp: In function 'int32_t main()':
boat.cpp:48:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |     for (int j = 0; j <= rrh.size(); ++j) f[id][j] = 0;
      |                     ~~^~~~~~~~~~~~~
boat.cpp:52:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |     for (int j = 0; j <= rrh.size(); ++j) f[id][j] = f[p][j];
      |                     ~~^~~~~~~~~~~~~
boat.cpp:59:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |   for (int i = 1; i <= rrh.size(); ++i) answer += f[n & 1][i];
      |                   ~~^~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 0 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42