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Submission #887203

# Submission time Handle Problem Language Result Execution time Memory
887203 2023-12-14T04:21:20 Z peterandvoi Event Hopping (BOI22_events) C++17
10 / 100
 802 ms 100928 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() {
    assert(n <= 5000);
    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);
        }
        if (res != 1e9) {
          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 Runtime error 29 ms 8768 KB Execution killed with signal 6
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 2392 KB Output is correct
3 Correct 10 ms 23028 KB Output is correct
4 Correct 8 ms 23132 KB Output is correct
5 Correct 13 ms 22872 KB Output is correct
6 Correct 8 ms 23024 KB Output is correct
7 Correct 9 ms 23128 KB Output is correct
8 Correct 9 ms 23132 KB Output is correct
9 Correct 8 ms 22876 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 2392 KB Output is correct
3 Correct 10 ms 23028 KB Output is correct
4 Correct 8 ms 23132 KB Output is correct
5 Correct 13 ms 22872 KB Output is correct
6 Correct 8 ms 23024 KB Output is correct
7 Correct 9 ms 23128 KB Output is correct
8 Correct 9 ms 23132 KB Output is correct
9 Correct 8 ms 22876 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 9 ms 23128 KB Output is correct
13 Correct 8 ms 23132 KB Output is correct
14 Correct 10 ms 23100 KB Output is correct
15 Correct 12 ms 23384 KB Output is correct
16 Correct 10 ms 23132 KB Output is correct
17 Correct 9 ms 23128 KB Output is correct
18 Correct 8 ms 22876 KB Output is correct
19 Correct 749 ms 100696 KB Output is correct
20 Correct 766 ms 100688 KB Output is correct
21 Correct 802 ms 100700 KB Output is correct
22 Incorrect 581 ms 100928 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 2392 KB Output is correct
2 Correct 1 ms 2392 KB Output is correct
3 Correct 10 ms 23028 KB Output is correct
4 Correct 8 ms 23132 KB Output is correct
5 Correct 13 ms 22872 KB Output is correct
6 Correct 8 ms 23024 KB Output is correct
7 Correct 9 ms 23128 KB Output is correct
8 Correct 9 ms 23132 KB Output is correct
9 Correct 8 ms 22876 KB Output is correct
10 Correct 1 ms 2392 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 9 ms 23004 KB Output is correct
13 Correct 8 ms 23008 KB Output is correct
14 Correct 9 ms 22876 KB Output is correct
15 Correct 8 ms 23132 KB Output is correct
16 Correct 9 ms 23132 KB Output is correct
17 Correct 9 ms 23132 KB Output is correct
18 Correct 7 ms 22876 KB Output is correct
19 Runtime error 32 ms 8596 KB Execution killed with signal 6
20 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Runtime error 28 ms 8796 KB Execution killed with signal 6
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 Runtime error 29 ms 8768 KB Execution killed with signal 6
3 Halted 0 ms 0 KB -