Submission #1125054

#	Time	Username	Problem	Language	Result	Execution time	Memory
1125054		tvladm2009	COVID tests (CEOI24_covid)	C++20	Compilation error	0 ms	0 KiB

Main

#include <cassert>
#include <cstdio>
#include <string>
#include <vector>

/// You may use:


using namespace std;


#define ll long long
#define ld long double
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()


// The number of students
int N;

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

// 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';

    printf("Q %s\n", mask_str.c_str());
    fflush(stdout);

    char answer;
    scanf(" %c", &answer);
    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.



vector<bool> ff;


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


void divide(int l, int r) {
    if (range(l, r) == 0) {   
        return;
    }
    if (l == r) {
        ff[l] = 1;
        return;
    }
    int m = (l + r) / 2;
    divide(l, m);
    divide(m + 1, r);
}


vector<bool> find_positive() {
    ff.resize(N);
    for (int i = 0; i < N; i += 1) {
      f[i] = 0;
    }
    divide(0, N - 1);
    return ff;
}


int main() {
    int T;
    scanf("%d %lf %d", &N, &P, &T);

    // You may perform any extra initialization here.

    for (int i = 0; i < T; i++) {
        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';

        printf("A %s\n", answer_str.c_str());
        fflush(stdout);

        char verdict;
        scanf(" %c", &verdict);
        if (verdict == 'W')
            exit(0);
    }

    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'std::vector<bool> find_positive()':
Main.cpp:81:7: error: 'f' was not declared in this scope
   81 |       f[i] = 0;
      |       ^
Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:39:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:90:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:106:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~