Submission #629216

#	Time	Username	Problem	Language	Result	Execution time	Memory
629216		flashmt	Rarest Insects (IOI22_insects)	C++17	99.89 / 100	77 ms	552 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 solveSmallTypeCount(int n, vector<int> occurrences)
{
  int typeCnt = size(occurrences);
  vector<int> cnt(typeCnt, 1);
  for (int i = 0; i < n; i++)
  {
    if (find(begin(occurrences), end(occurrences), i) != end(occurrences))
      continue;
 
    move_inside(i);
    int found = 0;
    for (int j = 1; j < size(occurrences); j++)
    {
      int cur = occurrences[j];
      move_inside(cur);
      if (press_button() == 2)
      {
        found = j;
        move_outside(cur);
        break;
      }
      move_outside(cur);
    }
    move_outside(i);
    cnt[found]++;
  }
 
  return *min_element(begin(cnt), end(cnt));
}
 
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);
  if (typeCnt <= 3)
    return solveSmallTypeCount(n, 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 = min(mid - 1, int(size(good)) / typeCnt + ans);
      id = good;
    }
  }
  return ans;
}

Compilation message (stderr)

insects.cpp: In function 'int solveSmallTypeCount(int, std::vector<int>)':
insects.cpp:34:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |     for (int j = 1; j < size(occurrences); j++)
      |                     ~~^~~~~~~~~~~~~~~~~~~
insects.cpp: In function 'int min_cardinality(int)':
insects.cpp:68:20: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   68 |     if (size(good) == typeCnt * (mid - ans))
      |         ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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