제출 #659825

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
659825		600Mihnea	Event Hopping (BOI22_events)	C++17	0 / 100	0 ms	212 KiB

events

bool home = 1;
#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 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 iq = 1; iq <= q; iq++) {
    int ff, ss;
    cin >> ff >> ss;
    for (int i = 1; i <= n; i++) {
      dp[i] = -1;
    }
    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 << dp[ss] << "\n";
  }

  return 0;
}
/**

**/

컴파일 시 표준 에러 (stderr) 메시지

events.cpp: In function 'int main()':
events.cpp:23:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30