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Submission #887095

# Submission time Handle Problem Language Result Execution time Memory
887095 2023-12-13T19:03:49 Z peterandvoi Event Hopping (BOI22_events) C++17
10 / 100
 780 ms 101012 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() {
    for (int i = 1; i <= n; ++i) {
      for (int j = 1; j <= n; ++j) {
        dp[i][j] = 1e9;
      }
    }
    queue<int> qu;
    for (int i = 1; i <= n; ++i) {
      while (qu.size()) {
        qu.pop();
      }
      dp[p[i]][p[i]] = 0; // just to remember
      qu.emplace(p[i]);
      for (int j = i - 1; j >= 1; --j) {
        int &res = dp[p[j]][p[i]];
        while (qu.size() && s[qu.front()] > e[p[j]]) {
          qu.pop();
        } 
        if (qu.size()) {
          res = min(res, dp[qu.front()][p[i]] + 1);
        }
        qu.emplace(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 23 ms 3288 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 2396 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 9 ms 22876 KB Output is correct
4 Correct 9 ms 22876 KB Output is correct
5 Correct 9 ms 22876 KB Output is correct
6 Correct 10 ms 22876 KB Output is correct
7 Correct 10 ms 22872 KB Output is correct
8 Correct 9 ms 22876 KB Output is correct
9 Correct 7 ms 22876 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 9 ms 22876 KB Output is correct
4 Correct 9 ms 22876 KB Output is correct
5 Correct 9 ms 22876 KB Output is correct
6 Correct 10 ms 22876 KB Output is correct
7 Correct 10 ms 22872 KB Output is correct
8 Correct 9 ms 22876 KB Output is correct
9 Correct 7 ms 22876 KB Output is correct
10 Correct 1 ms 2392 KB Output is correct
11 Correct 1 ms 2392 KB Output is correct
12 Correct 10 ms 22876 KB Output is correct
13 Correct 9 ms 22876 KB Output is correct
14 Correct 10 ms 23104 KB Output is correct
15 Correct 9 ms 23044 KB Output is correct
16 Correct 9 ms 22876 KB Output is correct
17 Correct 10 ms 22876 KB Output is correct
18 Correct 7 ms 23128 KB Output is correct
19 Correct 684 ms 100668 KB Output is correct
20 Correct 770 ms 100692 KB Output is correct
21 Correct 780 ms 101012 KB Output is correct
22 Incorrect 602 ms 100936 KB Output isn't correct
23 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 0 ms 2396 KB Output is correct
3 Correct 9 ms 22876 KB Output is correct
4 Correct 9 ms 22876 KB Output is correct
5 Correct 9 ms 22876 KB Output is correct
6 Correct 10 ms 22876 KB Output is correct
7 Correct 10 ms 22872 KB Output is correct
8 Correct 9 ms 22876 KB Output is correct
9 Correct 7 ms 22876 KB Output is correct
10 Correct 0 ms 2396 KB Output is correct
11 Correct 0 ms 2396 KB Output is correct
12 Correct 10 ms 23108 KB Output is correct
13 Correct 10 ms 23108 KB Output is correct
14 Correct 9 ms 22872 KB Output is correct
15 Correct 10 ms 23116 KB Output is correct
16 Correct 9 ms 22876 KB Output is correct
17 Correct 9 ms 23108 KB Output is correct
18 Correct 8 ms 22876 KB Output is correct
19 Incorrect 23 ms 3420 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 23 ms 3288 KB Output isn't correct
3 Halted 0 ms 0 KB -