Submission #308525

#	Time	Username	Problem	Language	Result	Execution time	Memory
308525		Peti	Counting Mushrooms (IOI20_mushrooms)	C++14	87.26 / 100	10 ms	384 KiB

mushrooms

#include "mushrooms.h"
#include <iostream>
#include <utility>
#include <vector>

using namespace std;

const int find_first = 125;

pair<int, int> ask_querry(vector<int> &inds, int &x, int &n){
    int m = min((int)inds.size()*2, (n-x)*2);
    m = min(m, n - n%2);
    vector<int> querry(m);

    for(int i = 0; i < m; i += 2)
        querry[i] = inds[i/2];
    for(int i = 1; i < m; i += 2)
        querry[i] = x++;

    return make_pair(use_machine(querry), m);
}

int count_mushrooms(int n) {
    int ret = 1, x = 1;
    vector<int> indsA, indsB;
    indsA.push_back(0);

    while((int)indsA.size() < 2 && (int)indsB.size() < 2)
    {
        if(x == n)
            return ret;
        vector<int> querry = {0, x};
        int ans = use_machine(querry);
        if(ans == 0)
        {
            indsA.push_back(x);
            ret++;
        }
        else
            indsB.push_back(x);
        x++;
    }

    while((int)indsA.size() < find_first && (int)indsB.size() < find_first)
    {
        if(x == n)
            return ret;
        if(x == n-1)
        {
            vector<int> querry = {0, x};
            int ans = use_machine(querry);
            if(ans == 0)
                return ret + 1;
            return ret;
        }

        vector<int> querry(4);
        if((int)indsA.size() > 1)
        {
            querry[0] = indsA[0];
            querry[2] = indsA[1];
            querry[1] = x;
            querry[3] = x+1;

            int ans = use_machine(querry);
            ret += 2 - (ans+1)/2;
            if(ans < 2)
                indsA.push_back(x);
            else
                indsB.push_back(x);
            if(ans%2 == 0)
                indsA.push_back(x+1);
            else
                indsB.push_back(x+1);
            x += 2;
        }
        else
        {
            querry[0] = indsB[0];
            querry[2] = indsB[1];
            querry[1] = x;
            querry[3] = x+1;

            int ans = use_machine(querry);
            ret += (ans+1)/2;
            if(ans >= 2)
                indsA.push_back(x);
            else
                indsB.push_back(x);
            if(ans%2 == 1)
                indsA.push_back(x+1);
            else
                indsB.push_back(x+1);
            x += 2;
        }
    }

    while(x < n)
    {
        if(indsA.size() > indsB.size())
        {
            pair<int, int> ans = ask_querry(indsA, x, n);

            if(ans.first%2 == 0)
                indsA.push_back(x-1);
            ret += ans.second/2 - (ans.first+1)/2;
        }
        else
        {
            pair<int, int> ans = ask_querry(indsB, x, n);

            if(ans.first%2 == 1)
                indsA.push_back(x-1);
            ret += (ans.first+1)/2;
        }
    }

	return ret;
}

• Subtask 1: 87.2587 / 100