Submission #847449

#	Time	Username	Problem	Language	Result	Execution time	Memory
847449		NeroZein	Rarest Insects (IOI22_insects)	C++17	94.76 / 100	39 ms	840 KiB

insects

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

int min_cardinality(int N) {
  int distinct = 0; 
  vector<bool> inserted(N); 
  for (int i = 0; i < N; ++i) {
    move_inside(i);
    int most_freq = press_button();
    if (most_freq > 1) {
      move_outside(i);
    } else {
      inserted[i] = true;
      distinct++; 
    }
  }
  vector<bool> bad(N); 
  int l = 1, r = N / distinct;
  while (l < r) {
    int mid = (l + r + 1) / 2;
    for (int i = 0; i < N; ++i) {
      if (bad[i]) {
        continue; 
      }
      move_inside(i);
      int most_freq = press_button();
      if (most_freq > mid) {
        move_outside(i); 
      } else {
        move_inside(i); 
        inserted[i] = true; 
      }
    }
    int cnt = accumulate(inserted.begin(), inserted.end(), 0); 
    if (cnt == distinct * mid) {//inserted indices must not be removed under any condition
      l = mid;
      for (int i = 0; i < N; ++i) {
        if (inserted[i]) {
          bad[i] = true; 
        }
      }
    } else {//non-inserted indices must not be inserted under any condition
      r = mid - 1; 
      for (int i = 0; i < N; ++i) {
        if (!inserted[i]) {
          bad[i] = true; 
        } else if (!bad[i]) {
          inserted[i] = false;
          move_outside(i); 
        }
      }
    }
  }
  return l;
}

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 69.76 / 75