Submission #624274

#	Time	Username	Problem	Language	Result	Execution time	Memory
624274		logTheorist	Counting Mushrooms (IOI20_mushrooms)	C++17	0 / 100	36 ms	464 KiB

mushrooms

#include "mushrooms.h"

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

const int INF	= 1e9;

int BLOCK;

int count_mushrooms(int n) {
	int mn = INF;
	for (int i = 1; i <= n; i++) {
		int nw = 2*i + (n-(2*i)) / i;
		if (nw < mn) {
			mn = nw;
			BLOCK = i;
		}
	}
	//cout << BLOCK << '\n';

	int fin;
	vector<int> A = {0}, B, Q;
	for (fin = 1; fin <= 2*BLOCK; fin++) {
		int t = use_machine({0, fin});
		if (t) {B.push_back(fin);}
		else {A.push_back(fin);}

		if (max(A.size(), B.size()) >= (int)(BLOCK+1)) {break;}
	}

	//for (auto &i : A) cout << i << ' '; cout << '\n';
	//for (auto &i : B) cout << i << ' '; cout << '\n';

	int ans = A.size();
	bool useB = 0;
	if (B.size() >= (int)(BLOCK+1)) {useB = 1;}

	for (fin++; fin < n; fin++) {Q.push_back(fin);}

	//for (auto &i : Q) cout << i << ' '; cout << '\n';

	if (!useB) {

		while (!Q.empty()) {
			vector<int> ask = {A[0]};
			int inMachine = 0;
			for (int i = 1; (!Q.empty()) && (i < (int)A.size()); i++) {
				ask.push_back(Q.back());
				Q.pop_back();
				ask.push_back(A[i]);
				inMachine++;
			}

			int tmp = use_machine(ask);
			ans += inMachine - (tmp/2);
		}

	} else {

		while (!Q.empty()) {
			vector<int> ask = {B[0]};
			int inMachine = 0;
			for (int i = 1; (!Q.empty()) && (i < (int)A.size()); i++) {
				ask.push_back(Q.back());
				Q.pop_back();
				ask.push_back(B[i]);
				inMachine++;
			}

			int tmp = use_machine(ask);
			ans += tmp/2;
		}

	}

	return ans;
}

#ifdef Zanite
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.

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

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:28:31: warning: comparison of integer expressions of different signedness: 'const long unsigned int' and 'int' [-Wsign-compare]
   28 |   if (max(A.size(), B.size()) >= (int)(BLOCK+1)) {break;}
      |       ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
mushrooms.cpp:36:15: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   36 |  if (B.size() >= (int)(BLOCK+1)) {useB = 1;}
      |      ~~~~~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 100