Submission #629159

#	Time	Username	Problem	Language	Result	Execution time	Memory
629159		flashmt	Rarest Insects (IOI22_insects)	C++17	99.89 / 100	69 ms	560 KiB

insects

#include <bits/stdc++.h>
#include "insects.h"
using namespace std;
 
pair<vector<int>, vector<int>> findFirstOccurrences(vector<int> id, int maxC)
{
  vector<int> good, bad;
  for (int i : id)
  {
    move_inside(i);
    if (press_button() <= maxC) good.push_back(i);
    else
    {
      move_outside(i);
      bad.push_back(i);
    }
  }
  for (int i : good)
    move_outside(i);
  return {good, bad};
}
 
int min_cardinality(int n)
{
  vector<int> id(n);
  iota(begin(id), end(id), 0);
  auto [good, bad] = findFirstOccurrences(id, 1);
  int typeCnt = size(good); 
  int low = 2, high = n / typeCnt, ans = 1;
  id = bad;
  while (low <= high)
  {
    int mid = (low + high) / 2;
    tie(good, bad) = findFirstOccurrences(id, mid - ans);
    if (size(good) == typeCnt * (mid - ans))
    {
      ans = mid;
      low = mid + 1;
      id = bad;
    }
    else
    {
      high = mid - 1;
      id = good;
    }
  }
  return ans;
}

Compilation message (stderr)

insects.cpp: In function 'int min_cardinality(int)':
insects.cpp:35:20: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   35 |     if (size(good) == typeCnt * (mid - ans))
      |         ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 74.89 / 75