Submission #967925

#	Time	Username	Problem	Language	Result	Execution time	Memory
967925		duckindog	Boat (APIO16_boat)	C++17	9 / 100	2016 ms	524288 KiB

boat

#include <bits/stdc++.h>
 
using namespace std;
 
const int N = 500 + 10,
          M = 1'000'000'000 + 7;
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;
  }
} f[2][1'000'000 + 10];
 
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 j = 1; j <= rrh.size(); ++j) f[0][j] = 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) f[id][j] += f[p][j - 1];
    for (int j = 1; j <= rrh.size(); ++j) {
      f[id][j] += f[id][j - 1] - f[p][j - 1];
    }
  }
  
  cout << f[n & 1][rrh.size()] - 1 << "\n";
}

Compilation message (stderr)

boat.cpp: In function 'int32_t main()':
boat.cpp:42:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |   for (int j = 1; j <= rrh.size(); ++j) f[0][j] = 1;
      |                   ~~^~~~~~~~~~~~~
boat.cpp:46:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |     for (int j = 0; j <= rrh.size(); ++j) f[id][j] = 0;
      |                     ~~^~~~~~~~~~~~~
boat.cpp:50:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |     for (int j = 0; j <= rrh.size(); ++j) f[id][j] = f[p][j];
      |                     ~~^~~~~~~~~~~~~
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 = 1; j <= rrh.size(); ++j) {
      |                     ~~^~~~~~~~~~~~~

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