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Submission #659834

# Submission time Handle Problem Language Result Execution time Memory
659834 2022-11-19T11:45:27 Z 600Mihnea Event Hopping (BOI22_events) C++17
10 / 100
 1500 ms 1492 KB 
bool home = 0;
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
const int N = (int) 1e5 + 7;
int n;
int q;

struct T {
  int l;
  int r;
};

T v[N];
int dp[N];
int nxt[N];

int main() {
  if (!home) {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  } else {
    freopen("input.txt", "r", stdin);
  }

  cin >> n >> q;
  for (int i = 1; i <= n; i++) {
    cin >> v[i].l >> v[i].r;
  }
  for (int i = 1; i <= n; i++) {
    nxt[i] = -1;
    for (int j = 1; j <= n; j++) {
      if (v[j].l <= v[i].r) {
        if (nxt[i] == -1) {
          nxt[i] = j;
        } else {
          if (v[j].r > v[nxt[i]].r) {
            nxt[i] = j;
          }
        }
      }
    }
    if (nxt[i] != -1 && v[i].r >= v[nxt[i]].r) {
      nxt[i] = -1;
    }
  }
  for (int iq = 1; iq <= q; iq++) {
    int ff, ss;
    cin >> ff >> ss;
    for (int i = 1; i <= n; i++) {
      dp[i] = -1;
    }
    int co = 0;
    while (nxt[ff] != -1 && v[nxt[ff]].r <= v[ss].l) {
      ff = nxt[ff];
      co++;
    }
    queue<int> q;
    q.push(ff);
    dp[ff] = 0;
    while (!q.empty()) {
      int a = q.front();
      q.pop();
      for (int b = 1; b <= n; b++) {
        if (v[b].l <= v[a].r && v[a].r <= v[b].r && dp[b] == -1) {
          dp[b] = 1 + dp[a];
          q.push(b);
        }
      }
    }
    if (dp[ss] == -1) {
      cout << "impossible\n";
      continue;
    }
  ///  assert(dp[ss] <= 3);
    cout << co + dp[ss] << "\n";
  }

  return 0;
}
/**

**/

Compilation message

events.cpp: In function 'int main()':
events.cpp:24:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Execution timed out 1589 ms 1492 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 50 ms 340 KB Output is correct
5 Correct 179 ms 340 KB Output is correct
6 Correct 125 ms 340 KB Output is correct
7 Correct 211 ms 340 KB Output is correct
8 Correct 193 ms 340 KB Output is correct
9 Correct 279 ms 340 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 50 ms 340 KB Output is correct
5 Correct 179 ms 340 KB Output is correct
6 Correct 125 ms 340 KB Output is correct
7 Correct 211 ms 340 KB Output is correct
8 Correct 193 ms 340 KB Output is correct
9 Correct 279 ms 340 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 5 ms 340 KB Output is correct
13 Correct 49 ms 344 KB Output is correct
14 Correct 180 ms 340 KB Output is correct
15 Correct 122 ms 340 KB Output is correct
16 Correct 216 ms 340 KB Output is correct
17 Correct 199 ms 340 KB Output is correct
18 Correct 278 ms 340 KB Output is correct
19 Execution timed out 1578 ms 340 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 50 ms 340 KB Output is correct
5 Correct 179 ms 340 KB Output is correct
6 Correct 125 ms 340 KB Output is correct
7 Correct 211 ms 340 KB Output is correct
8 Correct 193 ms 340 KB Output is correct
9 Correct 279 ms 340 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 5 ms 352 KB Output is correct
13 Correct 48 ms 340 KB Output is correct
14 Correct 180 ms 340 KB Output is correct
15 Correct 125 ms 340 KB Output is correct
16 Correct 212 ms 340 KB Output is correct
17 Correct 194 ms 340 KB Output is correct
18 Correct 282 ms 340 KB Output is correct
19 Execution timed out 1580 ms 1452 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1574 ms 1492 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Execution timed out 1589 ms 1492 KB Time limit exceeded
3 Halted 0 ms 0 KB -