Submission #629751

#	Time	Username	Problem	Language	Result	Execution time	Memory
629751		hltk	Rarest Insects (IOI22_insects)	C++17	47.50 / 100	262 ms	476 KiB

insects

#include "insects.h"

#include <vector>
#include <random>
#include <algorithm>
#include <numeric>

using namespace std;

int min_cardinality(int n) {
  vector<int> inds(n);
  iota(inds.begin(), inds.end(), 0);
  shuffle(inds.begin(), inds.end(), mt19937_64{});
  int types = 0;
  vector<int> x;
  for (int i : inds) {
    move_inside(i);
    if (press_button() == 1) {
      types++;
      x.push_back(i);
    } else {
      move_outside(i);
    }
  }
  if (types == 1 || types == n) {
    return 1 ^ n ^ types;
  }
  auto test = [&](int k) {
    vector<int> x;
    for (int i : inds) {
      move_inside(i);
      if (press_button() > k) {
        move_outside(i);
      } else {
        x.push_back(i);
      }
      if (x.size() == k * types) {
        break;
      }
    }
    for (int i : x) {
      move_outside(i);
    }
    return x.size() != k * types;
  };
  int l = 1, r = n - 1;
  while (l < r) {
    int m = (l + r) / 2;
    if (test(m + 1)) r = m;
    else l = m + 1;
  }
  return l;
}

Compilation message (stderr)

insects.cpp: In lambda function:
insects.cpp:37:20: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   37 |       if (x.size() == k * types) {
      |           ~~~~~~~~~^~~~~~~~~~~~
insects.cpp:44:21: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   44 |     return x.size() != k * types;
      |            ~~~~~~~~~^~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 22.5 / 75