oj.uz

Submission #887204

# Submission time Handle Problem Language Result Execution time Memory
887204 2023-12-14T04:34:47 Z peterandvoi Event Hopping (BOI22_events) C++17
25 / 100
 817 ms 100676 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];

bool equal(int i, int j) {
  return s[i] == s[j] && e[i] == e[j];  
}

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 = n; j >= 1; --j) {
        if (e[p[j]] > e[p[i]]) continue;
        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 2392 KB Output is correct
2 Incorrect 24 ms 3216 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 10 ms 22876 KB Output is correct
4 Correct 8 ms 23112 KB Output is correct
5 Correct 10 ms 22876 KB Output is correct
6 Correct 10 ms 22876 KB Output is correct
7 Correct 10 ms 22876 KB Output is correct
8 Correct 10 ms 23108 KB Output is correct
9 Correct 13 ms 23108 KB Output is correct

Subtask #3
15.0 / 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 10 ms 22876 KB Output is correct
4 Correct 8 ms 23112 KB Output is correct
5 Correct 10 ms 22876 KB Output is correct
6 Correct 10 ms 22876 KB Output is correct
7 Correct 10 ms 22876 KB Output is correct
8 Correct 10 ms 23108 KB Output is correct
9 Correct 13 ms 23108 KB Output is correct
10 Correct 1 ms 2396 KB Output is correct
11 Correct 1 ms 2396 KB Output is correct
12 Correct 11 ms 23104 KB Output is correct
13 Correct 8 ms 22876 KB Output is correct
14 Correct 10 ms 22876 KB Output is correct
15 Correct 8 ms 23128 KB Output is correct
16 Correct 9 ms 22876 KB Output is correct
17 Correct 9 ms 22872 KB Output is correct
18 Correct 13 ms 22876 KB Output is correct
19 Correct 690 ms 99652 KB Output is correct
20 Correct 817 ms 99388 KB Output is correct
21 Correct 780 ms 99920 KB Output is correct
22 Correct 565 ms 99920 KB Output is correct
23 Correct 630 ms 100676 KB Output is correct
24 Correct 632 ms 100660 KB Output is correct
25 Correct 811 ms 100432 KB Output is correct

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 10 ms 22876 KB Output is correct
4 Correct 8 ms 23112 KB Output is correct
5 Correct 10 ms 22876 KB Output is correct
6 Correct 10 ms 22876 KB Output is correct
7 Correct 10 ms 22876 KB Output is correct
8 Correct 10 ms 23108 KB Output is correct
9 Correct 13 ms 23108 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 23100 KB Output is correct
13 Correct 9 ms 22872 KB Output is correct
14 Correct 10 ms 22876 KB Output is correct
15 Correct 8 ms 22872 KB Output is correct
16 Correct 9 ms 22876 KB Output is correct
17 Correct 10 ms 23108 KB Output is correct
18 Correct 18 ms 22876 KB Output is correct
19 Incorrect 23 ms 3416 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 3416 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 2392 KB Output is correct
2 Incorrect 24 ms 3216 KB Output isn't correct
3 Halted 0 ms 0 KB -