Submission #629607

#	Time	Username	Problem	Language	Result	Execution time	Memory
629607		flashmt	Rarest Insects (IOI22_insects)	C++17	99.95 / 100	68 ms	440 KiB

insects

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

Compilation message (stderr)

insects.cpp: In function 'std::tuple<int, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> > > findFirstOccurrences(std::vector<int>, int, int)':
insects.cpp:12:20: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   12 |     if (size(good) == expectedSize)
      |         ~~~~~~~~~~~^~~~~~~~~~~~~~~
insects.cpp: In function 'int min_cardinality(int)':
insects.cpp:50:20: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   50 |     if (size(good) == expectedSize)
      |         ~~~~~~~~~~~^~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 74.95 / 75