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Submission #842206

# Submission time Handle Problem Language Result Execution time Memory
842206 2023-09-02T14:26:21 Z d4xn Event Hopping (BOI22_events) C++17
30 / 100
 98 ms 17132 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 || dp[j][z] == z || (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

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8536 KB Output is correct
2 Correct 76 ms 16872 KB Output is correct
3 Correct 85 ms 17088 KB Output is correct
4 Correct 93 ms 16936 KB Output is correct
5 Correct 91 ms 17132 KB Output is correct
6 Correct 85 ms 17132 KB Output is correct
7 Correct 85 ms 16972 KB Output is correct
8 Correct 55 ms 12892 KB Output is correct
9 Correct 63 ms 13056 KB Output is correct
10 Correct 77 ms 16688 KB Output is correct
11 Correct 75 ms 16840 KB Output is correct
12 Correct 38 ms 12996 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8792 KB Output is correct
2 Correct 1 ms 8536 KB Output is correct
3 Correct 1 ms 8540 KB Output is correct
4 Correct 1 ms 8536 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

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8792 KB Output is correct
2 Correct 1 ms 8536 KB Output is correct
3 Correct 1 ms 8540 KB Output is correct
4 Correct 1 ms 8536 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

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8792 KB Output is correct
2 Correct 1 ms 8536 KB Output is correct
3 Correct 1 ms 8540 KB Output is correct
4 Correct 1 ms 8536 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

# Verdict Execution time Memory Grader output
1 Correct 75 ms 17088 KB Output is correct
2 Correct 87 ms 17024 KB Output is correct
3 Correct 98 ms 17040 KB Output is correct
4 Correct 57 ms 12996 KB Output is correct
5 Correct 78 ms 16840 KB Output is correct
6 Correct 86 ms 16432 KB Output is correct
7 Correct 79 ms 16624 KB Output is correct
8 Correct 75 ms 16628 KB Output is correct
9 Correct 33 ms 10356 KB Output is correct
10 Correct 87 ms 16836 KB Output is correct
11 Correct 78 ms 15340 KB Output is correct
12 Correct 86 ms 16832 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8536 KB Output is correct
2 Correct 76 ms 16872 KB Output is correct
3 Correct 85 ms 17088 KB Output is correct
4 Correct 93 ms 16936 KB Output is correct
5 Correct 91 ms 17132 KB Output is correct
6 Correct 85 ms 17132 KB Output is correct
7 Correct 85 ms 16972 KB Output is correct
8 Correct 55 ms 12892 KB Output is correct
9 Correct 63 ms 13056 KB Output is correct
10 Correct 77 ms 16688 KB Output is correct
11 Correct 75 ms 16840 KB Output is correct
12 Correct 38 ms 12996 KB Output is correct
13 Correct 1 ms 8792 KB Output is correct
14 Correct 1 ms 8536 KB Output is correct
15 Correct 1 ms 8540 KB Output is correct
16 Correct 1 ms 8536 KB Output is correct
17 Incorrect 1 ms 8540 KB Output isn't correct
18 Halted 0 ms 0 KB -