oj.uz

Submission #1076758

# Submission time Handle Problem Language Result Execution time Memory
1076758 2024-08-26T16:14:17 Z raphaelp COVID tests (CEOI24_covid) C++14
39.73 / 100
 2245 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.
void rectest(int L, int R, vector<bool> &test, vector<bool> &answer)
{
    if (test_students(test) == 0)
        return;
    if (L == R)
    {
        answer[L] = 1;
        return;
    }
    int m = (L + R) / 2;
    for (int i = L; i <= m; i++)
        test[i] = 0;
    rectest(m + 1, R, test, answer);
    for (int i = L; i <= m; i++)
        test[i] = 1;
    for (int i = m + 1; i <= R; i++)
        test[i] = 0;
    rectest(L, m, test, answer);
}
std::vector<bool> find_positive()
{
    std::vector<bool> answer(N);
    int div = ceil((double)1 / P);
    vector<bool> test(N, 0);
    int L = 0, R = div - 1;
    while (true)
    {
        R = min(R, N - 1);
        L = min(L, N - 1);
        for (int i = L; i <= R; i++)
            test[i] = 1;
        rectest(L, R, test, answer);
        for (int i = L; i <= R; i++)
            test[i] = 0;
        if (R == N - 1)
            break;
        L += div, R += div;
    }
    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:82:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:99:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #0
0.0 / 0.0

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

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 344 KB Output is correct
2 Correct 8 ms 344 KB Output is correct
3 Correct 13 ms 344 KB Output is correct
4 Correct 9 ms 344 KB Output is correct
5 Correct 10 ms 344 KB Output is correct
6 Correct 13 ms 344 KB Output is correct
7 Correct 7 ms 344 KB Output is correct
8 Correct 8 ms 344 KB Output is correct
9 Correct 11 ms 344 KB Output is correct
10 Correct 6 ms 340 KB Output is correct
11 Correct 7 ms 344 KB Output is correct
12 Correct 10 ms 344 KB Output is correct
13 Correct 11 ms 344 KB Output is correct
14 Correct 6 ms 344 KB Output is correct
15 Correct 15 ms 344 KB Output is correct
16 Correct 8 ms 344 KB Output is correct
17 Correct 1 ms 344 KB Output is correct

Subtask #2
29.729999997 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 49 ms 344 KB Output is correct (P=0.001, F=15.1, Q=17.8) -> 52.47 points
2 Correct 169 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=75.4) -> 31.01 points
3 Correct 368 ms 344 KB Output is correct (P=0.011546, F=94.9, Q=143.0) -> 29.73 points
4 Correct 691 ms 344 KB Output is correct (P=0.028545, F=191.5, Q=283.4) -> 30.83 points
5 Correct 941 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=361.2) -> 31.40 points
6 Correct 1286 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=514.1) -> 34.41 points
7 Correct 1781 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=675.6) -> 35.83 points
8 Correct 2107 ms 344 KB Output is correct (P=0.158765, F=639.1, Q=848.2) -> 38.98 points
9 Correct 2245 ms 344 KB Output is correct (P=0.2, F=731.4, Q=954.3) -> 40.56 points