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Submission #659828

# Submission time Handle Problem Language Result Execution time Memory
659828 2022-11-19T11:41:05 Z 600Mihnea Event Hopping (BOI22_events) C++17
10 / 100
 1500 ms 1620 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;
    }
    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 1588 ms 1592 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 324 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 49 ms 368 KB Output is correct
5 Correct 181 ms 360 KB Output is correct
6 Correct 122 ms 340 KB Output is correct
7 Correct 219 ms 360 KB Output is correct
8 Correct 198 ms 360 KB Output is correct
9 Correct 277 ms 356 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 324 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 49 ms 368 KB Output is correct
5 Correct 181 ms 360 KB Output is correct
6 Correct 122 ms 340 KB Output is correct
7 Correct 219 ms 360 KB Output is correct
8 Correct 198 ms 360 KB Output is correct
9 Correct 277 ms 356 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 5 ms 340 KB Output is correct
13 Correct 54 ms 340 KB Output is correct
14 Correct 182 ms 340 KB Output is correct
15 Correct 121 ms 348 KB Output is correct
16 Correct 218 ms 364 KB Output is correct
17 Correct 195 ms 368 KB Output is correct
18 Correct 278 ms 356 KB Output is correct
19 Execution timed out 1574 ms 396 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 324 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 49 ms 368 KB Output is correct
5 Correct 181 ms 360 KB Output is correct
6 Correct 122 ms 340 KB Output is correct
7 Correct 219 ms 360 KB Output is correct
8 Correct 198 ms 360 KB Output is correct
9 Correct 277 ms 356 KB Output is correct
10 Correct 0 ms 340 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 5 ms 376 KB Output is correct
13 Correct 49 ms 340 KB Output is correct
14 Correct 183 ms 340 KB Output is correct
15 Correct 124 ms 356 KB Output is correct
16 Correct 219 ms 340 KB Output is correct
17 Correct 192 ms 360 KB Output is correct
18 Correct 281 ms 352 KB Output is correct
19 Execution timed out 1574 ms 1484 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 1568 ms 1620 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 1588 ms 1592 KB Time limit exceeded
3 Halted 0 ms 0 KB -