Submission #824436

#	Time	Username	Problem	Language	Result	Execution time	Memory
824436		ymm	Counting Mushrooms (IOI20_mushrooms)	C++17	35.15 / 100	7 ms	512 KiB

mushrooms

#include "mushrooms.h"
#include <bits/stdc++.h>
#define Loop(x,l,r) for (ll x = (l); x < (r); ++x)
typedef long long ll;
typedef std::pair<ll,ll> pll;
using namespace std;

vector<int> A, B, U;

void query1()
{
	if (!U.size())
		return;
	int x = U.back();
	U.pop_back();
	(use_machine({0, x})? B: A).push_back(x);
}
void query2()
{
	if (U.size() < 2 || (A.size() < 2 && B.size() < 2))
		return query1();
	int x = U.back(); U.pop_back();
	int y = U.back(); U.pop_back();
	if (A.size() >= 2) {
		int res = use_machine({A[0], x, A[1], y});
		int a = res/2;
		int b = res%2;
		(a? B: A).push_back(x);
		(b? B: A).push_back(y);
	} else {
		int res = use_machine({B[0], x, B[1], y});
		int a = res/2;
		int b = res%2;
		(a? A: B).push_back(x);
		(b? A: B).push_back(y);
	}
}
int other_A = 0;
void queryline()
{
	if (!U.size())
		return;
	auto &C = A.size() > B.size()? A: B;
	int cnt = min(A.size(), U.size());
	vector<int> vec;
	int lst = -1;
	Loop (i,0,cnt) {
		vec.push_back(C[i]);
		vec.push_back(U.back());
		lst = U.back();
		U.pop_back();
	}
	int res = use_machine(vec);
	int rl = res&1;
	if (A.size() > B.size()) {
		other_A += cnt-1-res/2;
		(rl? B: A).push_back(lst);
	} else {
		other_A += res/2;
		(rl? A: B).push_back(lst);
	}
}

int count_mushrooms(int n) {
	A.clear(); U.clear(); B.clear(); other_A = 0;
	A.push_back(0);
	Loop (i,1,n)
		U.push_back(i);
	Loop (_,0,100)
		query2();
	while (U.size())
		queryline();
	return A.size() + other_A;
}

• Subtask 1: 35.1477 / 100