Submission #1297866

#	Time	Username	Problem	Language	Result	Execution time	Memory
1297866		kawhiet	Counting Mushrooms (IOI20_mushrooms)	C++20	90.40 / 100	6 ms	572 KiB

mushrooms

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

constexpr int lim = 50;

int count_mushrooms(int n) {
	vector<int> a = {0}, b, s;
	if (use_machine({0, 1}) == 0) {
		a.push_back(1);
	} else {
		b.push_back(1);
	}
	if (n == 2) {
		return a.size();
	}
	if (use_machine({0, 2}) == 0) {
		a.push_back(2);
	} else {
		b.push_back(2);
	}
	for (int i = 3; i < n; i++) {
		s.push_back(i);
	}
	vector<int> w = (a.size() > b.size() ? a : b);
	bool is = (a == w);
	while (max(a.size(), b.size()) < lim && s.size() > 1) {
		int x = s.back(); s.pop_back();
		int y = s.back(); s.pop_back();
		int ret = use_machine({w[0], x, w[1], y});
		if (is) {
			if (ret == 0) {
				a.push_back(x);
				a.push_back(y);
			} else if (ret == 1) {
				a.push_back(x);
				b.push_back(y);
			} else if (ret == 2) {
				b.push_back(x);
				a.push_back(y);
			} else {
				b.push_back(x);
				b.push_back(y);
			}
		} else {
			if (ret == 0) {
				b.push_back(x);
				b.push_back(y);
			} else if (ret == 1) {
				b.push_back(x);
				a.push_back(y);
			} else if (ret == 2) {
				a.push_back(x);
				b.push_back(y);
			} else {
				a.push_back(x);
				a.push_back(y);
			}
		}
	}
	int res = a.size();
	while (!s.empty()) {
		vector<int> k = (a.size() > b.size() ? a : b);
		int m = min(k.size(), s.size());
		vector<int> t, v;
		for (int i = 0; i < m; i++) {
			t.push_back(k[i]);
			t.push_back(s.back());
			v.push_back(s.back());
			s.pop_back();
		}
		int cnt = use_machine(t);
		if (a == k) {
			if (cnt & 1) {
				b.push_back(v.back());
			} else {
				a.push_back(v.back());
			}
			res += m - (cnt + 1) / 2;
		} else {
			if (cnt & 1) {
				a.push_back(v.back());
			} else {
				b.push_back(v.back());
			}
			res += (cnt + 1) / 2;
		}
	}
	return res;
}

• Subtask 1: 90.4 / 100