Submission #725311

#	Time	Username	Problem	Language	Result	Execution time	Memory
725311		arush_agu	Boat (APIO16_boat)	C++17	9 / 100	596 ms	4052 KiB

boat

#include <algorithm>
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#ifdef DEBUG
#include <time.h>
#endif

#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x)                                                                 \
  {                                                                            \
    ++recur_depth;                                                             \
    auto x_ = x;                                                               \
    --recur_depth;                                                             \
    cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":"           \
         << __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl;         \
  }
#else
#define dbg(x)
#endif

using namespace std;
using namespace __gnu_pbds;

typedef pair<int, int> ii;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;

typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;

typedef vector<bool> vb;

template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
                         tree_order_statistics_node_update>;

template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
  return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
                                    !is_same<T_container, string>::value,
                                    typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
  os << '{';
  string sep;
  for (const T &x : v)
    os << sep << x, sep = ", ";
  return os << '}';
}

const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e18 + 10;
const ld EPS = 1e-9;

void solve() {
  int n; cin >> n;
  vll ab(n); for (auto &[x, y] : ab) cin >> x >> y;

  set<ll> s = {0, INF}; for (auto [x, y] : ab) s.insert(x), s.insert(y);
  vl uabs(all(s));
  vii idx_uabs(n);
  for (int i=0; i<n; i++) {
    idx_uabs[i].first = lower_bound(all(uabs), ab[i].first) - uabs.begin();
    idx_uabs[i].second = lower_bound(all(uabs), ab[i].second) - uabs.begin();
  }

  int m = uabs.size();

  vvl dp(n + 1, vl(m + 1, -1));
  function<ll(int, int)> f = [&](int idx, int mn_take_idx) -> ll {
    assert(idx < n);
    assert(mn_take_idx < m);
    auto [a, b] = ab[idx];

    ll mn_take = uabs[mn_take_idx];
    if (idx == n - 1) {
      if (mn_take < a) return (b - a + 1 + 1) % MOD;
      if (a <= mn_take && mn_take <= b) return (b - mn_take + 1 + 1) % MOD;
      return 1;
    }

    ll &x = dp[idx][mn_take_idx];
    if (x != -1) return x;

    x = f(idx + 1, mn_take_idx);
    for (int take_idx=max(mn_take_idx, idx_uabs[idx].first); take_idx<=idx_uabs[idx].second; take_idx++) {
      x += f(idx + 1, take_idx + 1);
      x %= MOD;
    }
    // ll take_idx = mn_take_idx;
    // for (ll take=max(a, mn_take); take<=b; take++) {
    //   while (uabs[take_idx] <= take) take_idx++;
    //   x += f(idx + 1, take_idx);
    //   x %= MOD;
    // }

    return x;
  };

  cout << (f(0, 0) - 1 + MOD) % MOD << "\n";
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);

  clock_t start = clock();

  int test_cases = 1;
  /* cin >> test_cases; */

  while (test_cases--)
    solve();

#ifdef DEBUG
  cerr << fixed << setprecision(10)
       << "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
       << "s\n";
#endif
  return 0;
}

Compilation message (stderr)

boat.cpp: In function 'int main()':
boat.cpp:144:11: warning: unused variable 'start' [-Wunused-variable]
  144 |   clock_t start = clock();
      |           ^~~~~

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