Submission #659916

#	Time	Username	Problem	Language	Result	Execution time	Memory
659916		peijar	Rarest Insects (IOI22_insects)	C++17	100 / 100	58 ms	436 KiB

insects

#include "insects.h"
#include <bits/stdc++.h>
using namespace std;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int randint(int lb, int ub) {
  return uniform_int_distribution<int>(lb, ub)(rng);
}

int min_cardinality(int N) {
  vector<int> roots;
  int nbCC = 0;
  for (int i = 0; i < N; ++i) {
    move_inside(i);
    if (i and press_button() == 2)
      move_outside(i);
    else
      roots.push_back(i), nbCC++;
  }
  vector<bool> isRoot(N);
  for (int r : roots)
    isRoot[r] = true;
  vector<int> toProcess;
  for (int i = 0; i < N; ++i)
    if (!isRoot[i])
      toProcess.push_back(i);
  if (nbCC == 1)
    return N;

  shuffle(toProcess.begin(), toProcess.end(), rng);
  set<int> inside(roots.begin(), roots.end());

  int lo = 1, up = N / nbCC;
  while (lo < up) {
    int mid = (lo + up + 1) / 2;
    vector<int> popped;
    vector<int> insideMachine;
    vector<int> notProcessed;
    for (int u : toProcess) {
      if ((int)inside.size() == nbCC * mid) {
        popped.push_back(u);
      } else {
        move_inside(u);
        inside.insert(u);
        if (press_button() > mid)
          popped.push_back(u), move_outside(u), inside.erase(u);
        else
          insideMachine.push_back(u);
      }
    }
    if ((int)popped.size() == N - mid * nbCC) {
      toProcess = popped;
      lo = mid;
    } else {
      for (int u : insideMachine)
        move_outside(u), inside.erase(u);
      toProcess = insideMachine;
      for (int x : notProcessed)
        toProcess.push_back(x);
      N = toProcess.size() + inside.size();
      up = mid - 1;
    }
  }
  return lo;
}

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 75 / 75