제출 #1234973

#제출 시각아이디문제언어결과실행 시간메모리
1234973trimkusCOVID tests (CEOI24_covid)C++20
0 / 100
14 ms416 KiB
#include <bits/stdc++.h>
using namespace std;
#define DEBUG
/// You may use:

// The number of students
int N;

// The probability any given student is positive
double P;

vector<bool> secret;


char ask(string m) {
	for (int i = 0; i < N; ++i) {
		if (m[i] == '1' && secret[i]) {
			return 'P';
		}
	}
	return 'N';
}

// This function performs a test on a subset of samples.
// Its argument is a vector of Booleans of length N,
// where the i-th element is true if the i-th sample should be added to the mix.
// It returns true if (and only if) at least one of the samples in the mix is positive.
bool test_students(std::vector<bool> mask) {
    assert(mask.size() == (size_t)N);

    std::string mask_str(N, ' ');
    for (int i = 0; i < N; i++)
        mask_str[i] = mask[i] ? '1' : '0';

    
    #ifdef DEBUG
	char answer = ask(mask_str);
	#endif
	#ifndef DEBUG
	printf("Q %s\n", mask_str.c_str());
	fflush(stdout);
    char answer;
    scanf(" %c", &answer);
	#endif
    return answer == 'P';
}

/// You should implement:

// This function will be called once for each test instance.
// It should use test_students to determine which samples are positive.
// It must return a vector of Booleans of length N,
// where the i-th element is true if and only if the i-th sample is positive.

bool query(int l, int r) {
	vector<bool> qr(N);
	for (int i = l; i <= r; ++i) {
		qr[i] = 1;
	}
	return test_students(qr);
}

std::vector<bool> find_positive() {
    std::vector<bool> answer(N);
	auto dfs = [&](auto& dfs, int l, int r) -> void {
		if (l == r) {
			answer[l] = 1;
			return;
		}
		int m = (l + r) / 2;
		if (query(l, m)) {
			dfs(dfs, l, m);
			double len = r - (m + 1) + 1;
			// cout << len << " = " << len * P << "\n";
			if (len * P >= 5 * P * P) {
				if (query(m + 1, r)) dfs(dfs, m + 1, r);
			}
		} else {
			dfs(dfs, m + 1, r);
		}
		
	};
	if (query(0, (N - 1) / 2)) dfs(dfs, 0, (N - 1) / 2);
    if (query((N - 1) / 2 + 1, N - 1)) dfs(dfs, (N - 1) / 2 + 1, N - 1);
	return answer;
}


void solve() {
	std::vector<bool> answer = find_positive();
	assert(answer.size() == (size_t)N);

	std::string answer_str(N, ' ');
	for (int j = 0; j < N; j++)
		answer_str[j] = answer[j] ? '1' : '0';
	#ifndef DEBUG
	printf("A %s\n", answer_str.c_str());
	#endif
	#ifdef DEBUG
	// cout << "E ";
	bool ok = true;
	for (int i = 0; i < N; ++i) {
		// cout << secret[i];
		if (secret[i] != answer[i]) ok = false;
	}
	// cout << "\n";
	#endif
	fflush(stdout);
	#ifdef DEBUG
	char verdict = (ok ? 'C' : 'W');
	#endif
	#ifndef DEBUG
	char verdict;
	scanf(" %c", &verdict);
	#endif
	if (verdict == 'W') {
		#ifdef DEBUG
		cout << "WA!\n";
		#endif
		exit(0);
	}
}
// Returns true with probability `p`, and false with probability `1 - p`
bool weighted_random_bool(double p) {
    static std::random_device rd;
    static std::mt19937 gen(rd());
    std::bernoulli_distribution d(p);
    return d(gen);
}

int main() {
    int T;
    scanf("%d %lf %d", &N, &P, &T);
	secret = vector<bool>(N);
    // You may perform any extra initialization here.
    for (int i = 0; i < T; i++) {
		#ifdef DEBUG
		for (int j = 0; j < N; ++j) {
			if (weighted_random_bool(P)) {
				secret[j] = 1;
			} else {
				secret[j] = 0;
			}
		}
		#endif
        solve();
    }
	#ifdef DEBUG
	cout << "AC!\n";
	#endif
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

Main.cpp: In function 'int main()':
Main.cpp:133:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  133 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
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