Submission #659890

#	Time	Username	Problem	Language	Result	Execution time	Memory
659890		peijar	Rarest Insects (IOI22_insects)	C++17	53.16 / 100	239 ms	424 KiB

insects

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

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);

  int lo = 1, up = N / nbCC;
  // invariant : everything outside of toProcess has majority element >= lo
  while (lo < up) {
    int mid = (lo + up + 1) / 2;
    vector<int> kept;
    vector<int> popped;
    for (int i : toProcess) {
      move_inside(i);
      if (press_button() > mid)
        popped.push_back(i), move_outside(i);
      else
        kept.push_back(i);
    }
    int cntPopped = popped.size();
    if (cntPopped == N - nbCC * mid) {
      lo = mid;
      toProcess = move(popped);
    } else {
      up = mid - 1;
      for (int i : kept)
        move_outside(i);
    }
  }
  return lo;
}

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 28.16 / 75