제출 #876376

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
876376		Kanon	버섯 세기 (IOI20_mushrooms)	C++14	95.76 / 100	5 ms	1056 KiB

mushrooms

#include <bits/stdc++.h>
#include "mushrooms.h"

using namespace std;

const int magic = 100;
const int bound = 226;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
// generate random number between l, r : uniform_int_distribution<long long>(l, r)(rng)
// random shuffle : shuffle(.begin(), .end(), rng)

int count_mushrooms(int n) {

  if (n <= bound + 1) {
    int ret = 1;
    for (int i = 1; i < n; i++) {
      ret += use_machine({0, i}) ^ 1;
    }
    return ret;
  }

  vector<int> a(n, -1);
  a[0] = 0;

  vector<int> zeros = {0};
  vector<int> ones;
  int cnt = 1;

  while (max(zeros.size(), ones.size()) < magic) {

    vector<int> ids = zeros.size() >= ones.size() ? zeros : ones;
    int memo = cnt;
    int L = cnt, R = cnt + min(ids.size(), magic - ids.size()) - 1;
    cnt = R + 1;

    int bit = ids == ones;

    vector<int> cur;
    for (int i = L; i <= R; i++) cur.push_back(i);
    shuffle(cur.begin(), cur.end(), rng);

    vector<int> que;
    for (int i = 0; i < (int) cur.size(); i++) {
      que.push_back(ids[i]);
      que.push_back(cur[i]);
    }

    int sum = use_machine(que);

    a[cur.back()] = bit ^ (sum & 1);
    sum -= a[cur.back()] ^ bit;
    sum >>= 1;
    cur.pop_back();
    sum = bit == 1 ? cur.size() - sum : sum;

    function<void(vector<int>, int)> solve = [&](vector<int> cur, int sum) {
      assert(sum >= 0 && sum <= (int) cur.size());
      if (sum == 0) {
        for (int i : cur) a[i] = 0;
        return;
      }
      if (sum == (int) cur.size()) {
        for (int i : cur) a[i] = 1;
        return;
      }

      assert(cur.size() >= 2);
      vector<int> Lq, Rq;
      int mid = cur.size() / 2;
      for (int i = 0; i < (int) cur.size(); i++) {
        if (i < mid) Lq.push_back(cur[i]);
        else Rq.push_back(cur[i]);
      }

      vector<int> p;
      for (int i = 0; i < (int) Lq.size(); i++) {
        p.push_back(ids[i]);
        p.push_back(Lq[i]);
      }
      p.push_back(ids[Lq.size()]);
      p.push_back(cnt++);

      int Lsum = use_machine(p);
      a[cnt - 1] = bit ^ (Lsum & 1);
      Lsum -= a[cnt - 1] ^ bit;
      Lsum >>= 1;
      Lsum = bit == 1 ? Lq.size() - Lsum : Lsum;

      solve(Lq, Lsum);
      solve(Rq, sum - Lsum);

    };

    solve(cur, sum);

    for (int i = memo; i < cnt; i++) {
      if (a[i] == 0) zeros.push_back(i);
      else ones.push_back(i);
    }
  }

  int ret = 0;
  ret += zeros.size();

  while (cnt < n) {

    int len = min(n - cnt, (int) max(zeros.size(), ones.size()));
    vector<int> ids = zeros.size() >= ones.size() ? zeros : ones;

    vector<int> que;
    for (int i = 0; i < len; i++) {
      que.push_back(ids[i]);
      que.push_back(cnt++);
    }

    int st = use_machine(que);

    if (ids == ones) {

      a[cnt - 1] = 1 ^ (st & 1);
      ret += a[cnt - 1] == 0;
      st -= a[cnt - 1] == 0;

      if (a[cnt - 1] == 0) zeros.push_back(cnt - 1);
      else ones.push_back(cnt - 1);

      assert(st % 2 == 0);
      ret += st >> 1;

    } else {

      a[cnt - 1] = 0 ^ (st & 1);
      ret += a[cnt - 1] == 0;
      st -= a[cnt - 1] == 1;

      if (a[cnt - 1] == 0) zeros.push_back(cnt - 1);
      else ones.push_back(cnt - 1);

      assert(st % 2 == 0);
      ret += (len - 1) - (st >> 1);

    }
  }
  return ret;

}

• Subtask 1: 95.7627 / 100