Submission #627945

#	Time	Username	Problem	Language	Result	Execution time	Memory
627945		lunchbox	Rarest Insects (IOI22_insects)	C++17	100 / 100	65 ms	336 KiB

insects

#include <bits/stdc++.h>
using namespace std;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef vector<int> vi;

#ifdef LOCAL
void move_inside(int i);
void move_outside(int i);
int press_button();
#else
#include "insects.h"
#endif

int min_cardinality(int n) {
  int c = 0;
  vi in(n), p(n);
  iota(p.begin(), p.end(), 0);
  for (int i = 0; i < n; i++) {
    move_inside(i);
    if (press_button() == 1) {
      c++;
      in[i] = 1;
    } else
      move_outside(i);
  }
  int low = 2, hi = n / c, sz = 0, ans = 1;
  while (low <= hi) {
    int t = (low + hi) / 2;
    vi v;
    shuffle(p.begin(), p.end(), rng);
    for (int i = 0; i < n; i++) {
      if (in[p[i]])
        continue;
      move_inside(p[i]);
      if (press_button() > t) {
        move_outside(p[i]);
        v.push_back(p[i]);
      } else
        sz++;
      if (c + sz == t * c) {
        for (int j = i + 1; j < n; j++)
          if (!in[p[j]])
            v.push_back(p[j]);
        break;
      }
    }
    if (c + sz == t * c) {
      fill(in.begin(), in.end(), 1);
      for (int i : v)
        in[i] = 0;
      ans = t;
      low = t + 1;
    } else {
      hi = t - 1;
      if (low <= hi) {
        for (int i : v)
          in[i] = 1;
        for (int i = 0; i < n; i++)
          if (!in[i]) {
            move_outside(i);
            sz--;
          }
      }
    }
  }
  return ans;
}

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