Submission #772718

#	Time	Username	Problem	Language	Result	Execution time	Memory
772718		cadmiumsky	Counting Mushrooms (IOI20_mushrooms)	C++17	80.71 / 100	7 ms	432 KiB

mushrooms

#include <bits/stdc++.h>
#include "mushrooms.h"
#define all(x) (x).begin(),(x).end()
using namespace std;

using ll = long long;
using ld = long double;

//#define int ll
#define sz(x) ((int)(x).size())

using pii = pair<int,int>;
using tii = tuple<int,int,int>;

int f(int x) { return (x + 1) / 2; }

int count_mushrooms(int n) {
  srand(time(0));
  int cnt[2] = {1, 0};
  vector<int> known[2];
  known[0].emplace_back(0);
  for(int i = 1; i < n;) {
    int T = (sz(known[0]) > sz(known[1])? 0 : 1);
    vector<int> cquery;
    int j;
    for(j = i; j < n && j - i < sz(known[T]); j++)
      cquery.emplace_back(known[T][j - i]),
      cquery.emplace_back(j);
    bool bulaneala = 0;
    if(known[T ^ 1].size()) {
      if(rand() % 2) {
        bulaneala = 1;
        cquery.back() = known[T ^ 1][rand() % sz(known[T ^ 1])];
        cquery.emplace_back(j - 1);
      }
    }
    i = i + sz(known[T]);
    //cerr << i << ":\n";
    //for(auto x : cquery) cerr << x << ' ';
    int A = use_machine(cquery) - bulaneala;
    if(bulaneala) A ^= 1;
    //cerr << "\n" << A << "\n--\n";
    cnt[T ^ 1] += f(A);
    cnt[T] += sz(cquery) / 2 - f(A);
    
    known[T ^ (A % 2)].emplace_back(cquery.back());
    
  }
  return cnt[0];
}

/**
      Anul asta se da centroid.
-- Surse oficiale
*/

• Subtask 1: 80.7143 / 100