oj.uz

답안 #842202

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
842202 2023-09-02T14:15:33 Z d4xn Event Hopping (BOI22_events) C++17
30 / 100
 107 ms 17156 KB 
#include <bits/stdc++.h>
using namespace std;

#define all(x) x.begin(), x.end()
#define tp3 tuple<int, int, int>

const int N = 1e5, L = 17;

int n, q, dp[L][N], ans[N];
pair<int, int> sg[N];
tp3 sgL[N], sgR[N];

signed main() {
  ios::sync_with_stdio(false); cin.tie(nullptr);

  cin >> n >> q;
  for (int i = 0; i < n; i++) {
    int l, r;
    cin >> l >> r;
    sg[i] = make_pair(l, r);
    sgL[i] = make_tuple(l, r, i);
    sgR[i] = make_tuple(r, l, i);
  }
  sort(sgL, sgL+n);
  sort(sgR, sgR+n);

  int curr = 0;
  int mx = -1;
  int mxIdx = -1;
  for (int i = 0; i < n; i++) {
    int r = get<0>(sgR[i]);
    int idx = get<2>(sgR[i]);

    while (curr < n && get<0>(sgL[curr]) <= r) {
      int nwMx = get<1>(sgL[curr]);
      if (nwMx > mx) {
        mx = nwMx;
        mxIdx = get<2>(sgL[curr]);
      }
      curr++;
    }

    if (mx >= r) {
      if (mx == r) dp[0][idx] = idx;
      else dp[0][idx] = mxIdx;
    }
    else dp[0][idx] = -1;
    //cerr << idx+1 << " " << dp[0][idx]+1 << endl;
  }//cerr << endl;

  for (int j = 1; j < L; j++) {
    for (int i = 0; i < n; i++) {
      dp[j][i] = dp[j-1][dp[j-1][i]];
    }
  }

  vector<tp3> queries;
  for (int i = 0; i < q; i++) {
    int x, y;
    cin >> x >> y;
    x--; y--;

    if (sg[y].second < sg[x].second) {
      //cerr << "-1 " << i << endl;
      ans[i] = -1;
    }
    else if (x == y) {
      //cerr << "0 " << i << endl;
      ans[i] = 0;
    }
    else if (sg[y].first <= sg[x].second && sg[x].second <= sg[y].second) {
      //cerr << "1 " << i << endl;
      ans[i] = 1;
    }
    else {
      //cerr << "2 " << i << endl;
      // ir a la r maxima que sea < sg[y].first
      int cnt = 0;
      int z = x;
      for (int j = L-1; j >= 0; j--) {
        if (dp[j][z] == -1 || sg[dp[j][z]].second >= sg[y].first || (j && dp[j-1][z] == dp[j][z])) continue;
        cnt += (1 << j);
        z = dp[j][z];
      }
      //cerr << cnt << " " << z+1 << endl;
      ans[i] = cnt;
      queries.push_back(make_tuple(sg[z].second, y, i));
    }
  }
  sort(all(queries));

  curr = 0;
  set<int> rs;
  for (auto& [r, y, idx] : queries) {
    while (curr < n && get<0>(sgL[curr]) <= r) {
      rs.insert(get<1>(sgL[curr]));
      curr++;
    }

    auto it = rs.lower_bound(sg[y].first);
    if (it != rs.end() && *it <= sg[y].second) {
      ans[idx] += 2;
    }
    else {
      ans[idx] = -1;
    }
  }

  for (int i = 0; i < q; i++) {
    if (ans[i] == -1) cout << "impossible\n";
    else cout << ans[i] << "\n";
  }
}

Subtask #1
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 8540 KB Output is correct
2 Correct 78 ms 17044 KB Output is correct
3 Correct 91 ms 17092 KB Output is correct
4 Correct 107 ms 17148 KB Output is correct
5 Correct 89 ms 17092 KB Output is correct
6 Correct 88 ms 17156 KB Output is correct
7 Correct 88 ms 17056 KB Output is correct
8 Correct 56 ms 12952 KB Output is correct
9 Correct 55 ms 13088 KB Output is correct
10 Correct 76 ms 16872 KB Output is correct
11 Correct 79 ms 16844 KB Output is correct
12 Correct 40 ms 13008 KB Output is correct

Subtask #2
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 8540 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 8540 KB Output is correct
4 Correct 1 ms 8540 KB Output is correct
5 Incorrect 1 ms 8540 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 8540 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 8540 KB Output is correct
4 Correct 1 ms 8540 KB Output is correct
5 Incorrect 1 ms 8540 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 8540 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 8540 KB Output is correct
4 Correct 1 ms 8540 KB Output is correct
5 Incorrect 1 ms 8540 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 76 ms 16996 KB Output is correct
2 Correct 88 ms 17000 KB Output is correct
3 Correct 96 ms 16836 KB Output is correct
4 Correct 55 ms 13000 KB Output is correct
5 Correct 77 ms 16768 KB Output is correct
6 Correct 80 ms 16584 KB Output is correct
7 Correct 88 ms 16516 KB Output is correct
8 Correct 76 ms 16620 KB Output is correct
9 Correct 32 ms 10576 KB Output is correct
10 Correct 85 ms 16756 KB Output is correct
11 Correct 78 ms 15512 KB Output is correct
12 Correct 93 ms 16832 KB Output is correct

Subtask #6
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 8540 KB Output is correct
2 Correct 78 ms 17044 KB Output is correct
3 Correct 91 ms 17092 KB Output is correct
4 Correct 107 ms 17148 KB Output is correct
5 Correct 89 ms 17092 KB Output is correct
6 Correct 88 ms 17156 KB Output is correct
7 Correct 88 ms 17056 KB Output is correct
8 Correct 56 ms 12952 KB Output is correct
9 Correct 55 ms 13088 KB Output is correct
10 Correct 76 ms 16872 KB Output is correct
11 Correct 79 ms 16844 KB Output is correct
12 Correct 40 ms 13008 KB Output is correct
13 Correct 2 ms 8540 KB Output is correct
14 Correct 1 ms 8540 KB Output is correct
15 Correct 2 ms 8540 KB Output is correct
16 Correct 1 ms 8540 KB Output is correct
17 Incorrect 1 ms 8540 KB Output isn't correct
18 Halted 0 ms 0 KB -