oj.uz

Submission #887094

# Submission time Handle Problem Language Result Execution time Memory
887094 2023-12-13T18:53:15 Z peterandvoi Event Hopping (BOI22_events) C++17
10 / 100
 1500 ms 99532 KB 
#include <bits/stdc++.h>

using namespace std;

#define db(...) " [" << #__VA_ARGS__ << " : " << (__VA_ARGS__) << "] "

const int N = 100005;

int n, q;
int s[N], e[N], p[N];

namespace sub3 {
  bool valid_input() {
    return n <= 5000;
  }
  
  int dp[5005][5005];
  
  void solve() {
    multiset<int> cur;
    priority_queue<pair<int, int>> pq;
    for (int i = 1; i <= n; ++i) {
      for (int j = 1; j <= n; ++j) {
        dp[i][j] = 1e9;
      }
    }
    for (int i = 1; i <= n; ++i) {
      while (pq.size()) {
        pq.pop();
      }
      cur.clear();
      dp[p[i]][p[i]] = 0; // just to remember
      cur.insert(0);
      pq.emplace(s[p[i]], p[i]);
      for (int j = i - 1; j >= 1; --j) {
        int &res = dp[p[j]][p[i]];
        while (pq.size() && pq.top().first > e[p[j]]) {
          cur.erase(cur.find(dp[pq.top().second][p[i]]));
          pq.pop();
        }
        if (cur.size()) {
          res = min(res, *cur.begin() + 1);
        }
        cur.insert(res);
        pq.emplace(s[p[j]], p[j]);
      }
    }
    while (q--) {
      int s, t;
      cin >> s >> t;
      if (dp[s][t] == 1e9) {
        cout << "impossible\n";
      } else {
        cout << dp[s][t] << '\n';
      }
    }
  }
}

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> q;
  for (int i = 1; i <= n; ++i) {
    cin >> s[i] >> e[i];
  }
  vector<int> ord(n);
  iota(ord.begin(), ord.end(), 1);
  sort(ord.begin(), ord.end(), [&](int x, int y) {
    return e[x] == e[y] ? s[x] < s[y] : e[x] < e[y];
  });
  for (int i = 0; i < n; ++i) {
    p[i + 1] = ord[i];
  }
  if (sub3::valid_input()) {
    sub3::solve();
  }
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Incorrect 26 ms 5504 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 29 ms 23008 KB Output is correct
4 Correct 25 ms 22876 KB Output is correct
5 Correct 25 ms 22872 KB Output is correct
6 Correct 84 ms 23128 KB Output is correct
7 Correct 99 ms 23140 KB Output is correct
8 Correct 62 ms 23132 KB Output is correct
9 Correct 66 ms 23636 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 29 ms 23008 KB Output is correct
4 Correct 25 ms 22876 KB Output is correct
5 Correct 25 ms 22872 KB Output is correct
6 Correct 84 ms 23128 KB Output is correct
7 Correct 99 ms 23140 KB Output is correct
8 Correct 62 ms 23132 KB Output is correct
9 Correct 66 ms 23636 KB Output is correct
10 Correct 1 ms 2392 KB Output is correct
11 Correct 1 ms 2392 KB Output is correct
12 Correct 30 ms 23128 KB Output is correct
13 Correct 26 ms 22872 KB Output is correct
14 Correct 28 ms 22876 KB Output is correct
15 Correct 72 ms 23132 KB Output is correct
16 Correct 109 ms 23152 KB Output is correct
17 Correct 64 ms 23172 KB Output is correct
18 Correct 63 ms 23128 KB Output is correct
19 Execution timed out 1522 ms 99532 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2392 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 29 ms 23008 KB Output is correct
4 Correct 25 ms 22876 KB Output is correct
5 Correct 25 ms 22872 KB Output is correct
6 Correct 84 ms 23128 KB Output is correct
7 Correct 99 ms 23140 KB Output is correct
8 Correct 62 ms 23132 KB Output is correct
9 Correct 66 ms 23636 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 31 ms 23504 KB Output is correct
13 Correct 25 ms 23132 KB Output is correct
14 Correct 24 ms 23096 KB Output is correct
15 Correct 70 ms 22876 KB Output is correct
16 Correct 93 ms 23128 KB Output is correct
17 Correct 68 ms 23132 KB Output is correct
18 Correct 64 ms 23132 KB Output is correct
19 Incorrect 24 ms 5212 KB Output isn't correct
20 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Incorrect 23 ms 3420 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Incorrect 26 ms 5504 KB Output isn't correct
3 Halted 0 ms 0 KB -