oj.uz

Submission #887096

# Submission time Handle Problem Language Result Execution time Memory
887096 2023-12-13T19:05:57 Z peterandvoi Event Hopping (BOI22_events) C++17
10 / 100
 793 ms 99924 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);
        }
        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 0 ms 2396 KB Output is correct
2 Incorrect 23 ms 3208 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 10 ms 22876 KB Output is correct
4 Correct 8 ms 22872 KB Output is correct
5 Correct 9 ms 23096 KB Output is correct
6 Correct 8 ms 22996 KB Output is correct
7 Correct 9 ms 23120 KB Output is correct
8 Correct 10 ms 22872 KB Output is correct
9 Correct 7 ms 23128 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 10 ms 22876 KB Output is correct
4 Correct 8 ms 22872 KB Output is correct
5 Correct 9 ms 23096 KB Output is correct
6 Correct 8 ms 22996 KB Output is correct
7 Correct 9 ms 23120 KB Output is correct
8 Correct 10 ms 22872 KB Output is correct
9 Correct 7 ms 23128 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 0 ms 2396 KB Output is correct
12 Correct 11 ms 22876 KB Output is correct
13 Correct 8 ms 22876 KB Output is correct
14 Correct 10 ms 23080 KB Output is correct
15 Correct 8 ms 22872 KB Output is correct
16 Correct 9 ms 23080 KB Output is correct
17 Correct 9 ms 23132 KB Output is correct
18 Correct 7 ms 22876 KB Output is correct
19 Correct 734 ms 99908 KB Output is correct
20 Correct 793 ms 99388 KB Output is correct
21 Correct 789 ms 99916 KB Output is correct
22 Incorrect 552 ms 99924 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 10 ms 22876 KB Output is correct
4 Correct 8 ms 22872 KB Output is correct
5 Correct 9 ms 23096 KB Output is correct
6 Correct 8 ms 22996 KB Output is correct
7 Correct 9 ms 23120 KB Output is correct
8 Correct 10 ms 22872 KB Output is correct
9 Correct 7 ms 23128 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 10 ms 22876 KB Output is correct
13 Correct 9 ms 22876 KB Output is correct
14 Correct 12 ms 22872 KB Output is correct
15 Correct 13 ms 22872 KB Output is correct
16 Correct 10 ms 23112 KB Output is correct
17 Correct 13 ms 22872 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 33 ms 3448 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2396 KB Output is correct
2 Incorrect 23 ms 3208 KB Output isn't correct
3 Halted 0 ms 0 KB -