Submission #415658

#	Time	Username	Problem	Language	Result	Execution time	Memory
415658		MKopchev	Counting Mushrooms (IOI20_mushrooms)	C++14	92.62 / 100	13 ms	448 KiB

mushrooms

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

int use_machine(std::vector<int> x);
/*
int other(int n,int t)
{
    int ret=t+2;

    int SZ=t+1;

    n=n-3-2*t;

    while(n>=0)
    {
        n=n-SZ;
        ret++;

        if(n>0)
        {
            n=n-SZ;
            ret++;
        }

        SZ++;
    }

    return ret;
}
int eval(int n)
{
    for(int t=1;t<=300;t++)
    {
        cout<<t<<" -> "<<other(n,t)<<endl;
    }
}
*/
int count_mushrooms(int n) {

    //cout<<"n= "<<n<<endl;

    if(n<=200)
    {
        int ret=1;

        for(int i=1;i<n;i++)
            ret+=1-use_machine({0,i});

        return ret;
    }
    //cout<<eval(2e4)<<endl;

	int outp=1;

	vector<int> seen[2]={{},{}};

	seen[0].push_back(0);

	int pointer=1;

	int BLOCK=85;

	while(seen[0].size()<2&&seen[1].size()<2)
    {
        int cur=use_machine({0,pointer});

        seen[cur].push_back(pointer);

        pointer++;

        outp=outp+(1-cur);
    }

    for(int i=0;i<BLOCK;i++)
    {
        //cout<<"i "<<i<<" pointer "<<pointer<<endl;

        int id=0;
        if(seen[id].size()<2)id=1;

        vector<int> me={seen[id][0],pointer,seen[id][1],pointer+1};

        int cnt[2]={0,0};

        int cur=use_machine(me);

        if(cur/2==0)
        {
            seen[id].push_back(pointer);
            cnt[id]++;
        }
        else
        {
            seen[!id].push_back(pointer);
            cnt[!id]++;
        }

        if(cur%2==0)
        {
            seen[id].push_back(pointer+1);
            cnt[id]++;
        }
        else
        {
            seen[!id].push_back(pointer+1);
            cnt[!id]++;
        }

        outp+=cnt[0];

        pointer+=2;
    }

	while(pointer<n)
    {
        int id=0;
        if(seen[0].size()<seen[1].size())id=1;

        vector<int> me={};

        for(auto w:seen[id])
        {
            me.push_back(w);
            me.push_back(pointer);

            pointer++;

            if(pointer==n)break;
        }

        int cur=use_machine(me);

        int cnt[2]={0,0};

        cnt[!id]=cur/2+cur%2;
        cnt[id]=me.size()/2-cnt[!id];

        outp+=cnt[0];

        /*
        cout<<"me: ";for(auto w:me)cout<<w<<" ";cout<<endl;
        cout<<"cnt: "<<cnt[0]<<" "<<cnt[1]<<endl;
        */

        if(cur%2==0)seen[id].push_back(me.back());
        else seen[!id].push_back(me.back());
    }

    return outp;
}
/*
static char fmt_buffer[100000];
#define FMT_TO_STR(fmt, result) va_list vargs; va_start(vargs, fmt); \
	vsnprintf(fmt_buffer, sizeof(fmt_buffer), fmt, vargs); \
	va_end(vargs); fmt_buffer[sizeof(fmt_buffer)-1] = 0; \
	std::string result(fmt_buffer);

static const int min_n = 2;
static const int max_n = 20000;
static const int max_qc = 20000;
static const int max_qs = 100000;
static const int species_A = 0;
static const int species_B = 1;

static int n;
static std::vector<int> species;
static int qc, qs;

static inline void error_if(bool cond, std::string message) {
	if (cond) {
		printf("%s\n", message.c_str());
		exit(0);
	}
}

static inline void wrong_if(bool cond, std::string message) {
	error_if(cond, "Wrong Answer: "+message);
}

int use_machine(std::vector<int> x) {
	const int xs = x.size();
	wrong_if(xs < 2, "Too small array for query.");
	wrong_if(xs > n, "Too large array for query.");
	qc++;
	wrong_if(qc > max_qc, "Too many queries.");
	qs += xs;
	wrong_if(qs > max_qs, "Too many total array sizes as queries.");
	for (int i = 0; i < xs; i++)
		wrong_if(x[i] < 0 || n - 1 < x[i], "Invalid value in the query array.");
	std::vector<bool> used(n, false);
	for (int i = 0; i < xs; i++) {
		wrong_if(used[x[i]], "Duplicate value in the query array.");
		used[x[i]] = true;
	}
	int diffs = 0;
	for (int i = 1; i < xs; i++)
		diffs += int(species[x[i]] != species[x[i-1]]);
	return diffs;
}

#ifdef __GNUC__
__attribute__ ((format(printf, 2, 3)))
#endif
static inline void check_input(bool cond, const char* message_fmt, ...) {
	FMT_TO_STR(message_fmt, message);
	error_if(!cond, "Invalid input: "+message);
}

int main() {

	check_input(1 == scanf("%d", &n), "Could not read n.");
	check_input(min_n <= n, "n must not be less than %d, but it is %d.", min_n, n);
	check_input(n <= max_n, "n must not be greater than %d, but it is %d.", max_n, n);
	species.resize(n);
	for (int i = 0; i < n; i++) {
		check_input(1 == scanf("%d", &species[i]), "Could not read species element [%d].", i);
		check_input(species[i]==species_A || species[i] == species_B,
					"Species elements must be %d or %d, but species element [%d] is %d.", species_A, species_B, i, species[i]);
	}
	check_input(species[0] == species_A, "Species element [%d] must be %d.", 0, species_A);
	// Postponed closing standard input in order to allow interactive usage of the grader.

    n=2e4;

    species.resize(n);

    for(int i=1;i<n;i++)
        species[i]=rand()%2;

    int outp=0;
    for(int i=0;i<n;i++)
        outp+=1-species[i];

    cout<<"outp= "<<outp<<endl;

	qc = 0;
	qs = 0;
	int answer = count_mushrooms(n);
	printf("%d\n%d\n", answer, qc);
	fclose(stdout);
	fclose(stdin);
	return 0;
}
*/

• Subtask 1: 92.623 / 100