Submission #1080004

#	Time	Username	Problem	Language	Result	Execution time	Memory
1080004		UmairAhmadMirza	Counting Mushrooms (IOI20_mushrooms)	C++17	80.43 / 100	6 ms	692 KiB

mushrooms

#include <bits/stdc++.h>
using namespace std;
 
int const N=20005;
int const H=141;
 
int use_machine(vector<int> x);

int solve(int n){
	vector<int> A,B;
	A.push_back(0);
	vector<int> q;
	q.push_back(0);
	for(int i=1;i<n;i++){
		q.push_back(i);
		if(use_machine(q))
			B.push_back(i);
		else
			A.push_back(i);
		q.pop_back();
	}
	return int(A.size());
}
 
int count_mushrooms(int n){
	if(n<=300)
		return solve(n);
	vector<int> A,B;
	A.push_back(0);
	vector<int> q;
	q.push_back(0);
	for(int i=1;i<n;i++){
		q.push_back(i);
		if(use_machine(q))
			B.push_back(i);
		else
			A.push_back(i);
		q.pop_back();
		if(A.size()>=2 || B.size()>=2)
			break;
	}
	bool bl=0;
	if(A.size()<B.size()){
		swap(A,B);
		bl=1;
	}
	for (int i = (A.size()+B.size()); i < n; i+=2)
	{
		q.clear();
		q.push_back(A[0]);
		q.push_back(i);
		q.push_back(A[1]);
		q.push_back(i+1);
		int v=use_machine(q);
		if(v%2==0)
			A.push_back(i+1);
		else
			B.push_back(i+1);

		if(v>=2)
			B.push_back(i);
		else
			A.push_back(i);
		if(A.size()>=H || B.size()>=H)
			break;
	}
	if(bl){
		bl=0;
		swap(A,B);
	}
	if(A.size()<B.size()){
		bl=1;
		swap(A,B);
	}
	int cntA=A.size(),cntB=B.size();
	for(int i=(A.size()+B.size());i<n;i+=H){
		vector<int> q;
		for(int j=i;j<min(i+H,n);j++){
			q.push_back(A[j-i]);
			q.push_back(j);
		}
		int v=use_machine(q)+1;
		cntB+=v/2;
	}
	cntA=n-cntB;
	if(bl)
		swap(cntB,cntA);
	return cntA;
}

• Subtask 1: 80.427 / 100