oj.uz

Submission #1076710

# Submission time Handle Problem Language Result Execution time Memory
1076710 2024-08-26T15:45:27 Z raphaelp COVID tests (CEOI24_covid) C++14
0 / 100
 4186 ms 344 KB 
#include <bits/stdc++.h>
using namespace std;

/// You may use:

// 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.
std::vector<bool> find_positive()
{
    std::vector<bool> answer(N);
    vector<bool> left(N, 1);
    vector<bool> test(N);
    while (test_students(left))
    {
        int L = 0, R = N;
        while (L != R)
        {
            int m = (L + R) / 2;
            for (int i = L; i <= m; i++)
                test[i] = (1 & left[i]);
            bool ans = test_students(test);
            for (int i = L; i <= m; i++)
                test[i] = 0;
            if (ans)
                R = m;
            else
                L = m + 1;
        }
        answer[L] = 1;
        left[L] = 0;
    }
    return answer;
}

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

Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:28:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:68:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:85:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   85 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct

Subtask #1
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 68 ms 344 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0.0 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 344 KB Output is correct (P=0.001, F=15.1, Q=11.0) -> 90.00 points
2 Correct 138 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=56.8) -> 62.23 points
3 Correct 315 ms 344 KB Output is correct (P=0.011546, F=94.9, Q=126.2) -> 38.81 points
4 Correct 808 ms 344 KB Output is correct (P=0.028545, F=191.5, Q=313.6) -> 25.35 points
5 Correct 1139 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=440.7) -> 21.65 points
6 Correct 2013 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=759.2) -> 17.00 points
7 Correct 2959 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=1153.3) -> 14.04 points
8 Execution timed out 4186 ms 344 KB Time limit exceeded (wall clock)
9 Halted 0 ms 0 KB -