Submission #836595

#	Time	Username	Problem	Language	Result	Execution time	Memory
836595		NeroZein	Counting Mushrooms (IOI20_mushrooms)	C++17	25 / 100	25 ms	456 KiB

mushrooms

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

int count_mushrooms(int n) {
  int b = max(3, (int) sqrt(n) + 20); 
  vector<int> ones;
  vector<int> zeros = {0};
  for (int i = 1; i < min(n, b); ++i) {
    if (use_machine({0, i}) == 0) {
      zeros.push_back(i); 
    } else {
      ones.push_back(i); 
    }
  }
  int cnt = 0; 
  int p = b;
  while (p < n) {
    vector<int> ask; 
    int pv = 1; 
    if (ones.size() > zeros.size()) {
      ask.push_back(ones[0]); 
      int oldp = p; 
      while (p < n && pv < (int) ones.size()) {
        ask.push_back(p++);
        ask.push_back(ones[pv++]);
      }
      int tmp = use_machine(ask) / 2;
      if (p < n / 10 && tmp >= (int) ones.size() / 2) {
        for (int i = oldp; i < p; ++i) {
          if (use_machine({0, i}) == 0) {
            zeros.push_back(i); 
          } else {
            ones.push_back(i); 
          }
        }
      } else {
        cnt += tmp; 
      }
    } else {
      ask.push_back(zeros[0]);
      int tot = 0; 
      int oldp = p; 
      while (p < n && pv < (int) zeros.size()) {
        ask.push_back(p++);
        ask.push_back(zeros[pv++]); 
        tot += 2; 
      }
      int tmp = use_machine(ask);
      if (p < n / 10 && (tot - tmp) / 2 >= (int) zeros.size() / 2) {
        for (int i = oldp; i < p; ++i) {
          if (use_machine({0, i}) == 0) {
            zeros.push_back(i); 
          } else {
            ones.push_back(i); 
          }
        }
      } else {
        cnt += (tot - tmp) / 2;
      }
    }
  }
  return zeros.size() + cnt;
}

• Subtask 1: 25 / 100