Submission #1031126

#	Time	Username	Problem	Language	Result	Execution time	Memory
1031126		happy_node	Counting Mushrooms (IOI20_mushrooms)	C++17	57.07 / 100	7 ms	600 KiB

mushrooms

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

const int B=200;

int count_mushrooms(int N) {
	vector<int> posA, posB;
	posA.push_back(0);

	for(int i=1;i+1<min(N,B);i+=2) {
		int r=use_machine({i,0,i+1});
		if(r==0) {
			posA.push_back(i);
			posA.push_back(i+1);
		} else if(r==1) {
			if(use_machine({0,i})==0) {
				posA.push_back(i);
				posB.push_back(i+1);
			} else {
				posB.push_back(i);
				posA.push_back(i+1);
			}
		} else {
			posB.push_back(i);
			posB.push_back(i+1);
		}
	}

	if((min(N,B)-1)&1) {
		if(use_machine({0,min(N,B)-1})==0) {
			posA.push_back(min(N,B)-1);
		} else {
			posB.push_back(min(N,B)-1);
		}
	} 

	int ans=posA.size();

	if(posA.size()>posB.size()) {
		int s=posA.size();
		for(int i=B;i<N;i+=s) {
			vector<int> qry;
			for(int j=i;j<min(N,i+s);j++) {
				qry.push_back(posA[j-i]);
				qry.push_back(j);
			}	
			int w=use_machine(qry);
			w=(w+1)/2;
			ans+=(qry.size()/2-w);
		}
	} else {
		int s=posB.size();
		for(int i=B;i<N;i+=s) {
			vector<int> qry;
			for(int j=i;j<min(N,i+s);j++) {
				qry.push_back(posB[j-i]);
				qry.push_back(j);
			}	
			int w=use_machine(qry);
			w=(w+1)/2;
			ans+=w;
		}
	}

	return ans;
}

• Subtask 1: 57.0707 / 100