Submission #1203139

#	Time	Username	Problem	Language	Result	Execution time	Memory
1203139		LucaLucaM	Rarest Insects (IOI22_insects)	C++20	0 / 100	0 ms	412 KiB

insects

#include "insects.h"
#include <vector>
#include <algorithm>
#include <cassert>
#include <random>
#include <iostream>

std::mt19937 rng(123);

int min_cardinality(int n) {
  std::vector<int> reprezentant;
  std::vector<int> order(n);
  for (int i = 0; i < n; i++) {
    order[i] = i;
  }
  std::shuffle(order.begin(), order.end(), rng);
  for (int i : order) {
    move_inside(i);
    if (press_button() >= 2) {
      move_outside(i);
    } else {
      reprezentant.push_back(i);
    }
  }

  std::vector<bool> taken(n, false);

  if ((int) reprezentant.size() > n / 2) {
    return 1;
  }

  int D = (int) reprezentant.size();
  
  if (D >= 15) { // caut binar ts
    auto check = [&](int mid) {
      std::vector<int> inside;
      for (int i : order) {
        move_inside(i);
        inside.push_back(i);
        if (press_button() > mid) {
          move_outside(i);
          inside.pop_back();
        }
      }
      int sz = (int) inside.size();
      for (int i : inside) {
        move_outside(i);
      }
      if (sz == D * mid) {
        return true;
      } else {
        return false;
      }
    };

    int l = 1, r = n / D;
    while (l < r) {
      int mid = (l + r + 1) / 2;
      if (check(mid)) {
        l = mid;
      } else {
        r = mid - 1;
      }
    }
    return r;
  } else {
    std::vector<int> where(n, 0);
    for (int i : reprezentant) {
      where[i] = -1;
    }
    for (int bit = 0; bit <= std::__lg(n); bit++) {
      for (int i = 0; i < D; i++) {
        if (i >> bit & 1) {
          move_inside(reprezentant[i]);
        }
      }
      for (int i = 0; i < n; i++) {
        if (where[i] != -1) {
          move_inside(i);
          if (press_button() == 2) {
            where[i] |= 1 << bit;
          }
          move_outside(i);
        }
      } 
      for (int i = 0; i < D; i++) {
        if (i >> bit & 1) {
          move_outside(reprezentant[i]);
        }
      }
    }

    std::vector<int> f(D, 1);
    for (int i = 0; i < n; i++) {
      if (where[i] != -1) {
        f[where[i]]++;
      }
    }
    return *std::min_element(f.begin(), f.end());
  }
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 15
• Subtask 3: 0 / 75