oj.uz

Submission #1116473

# Submission time Handle Problem Language Result Execution time Memory
1116473 2024-11-21T17:06:37 Z ortsac COVID tests (CEOI24_covid) C++17
0 / 100
 5177 ms 336 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.
vector<bool> find_positive() {
    int n = N;
    vector<bool> answer(n);
    int curr = -1;
    while (curr < (n - 1)) {
        int l = curr + 1, r = n - 1, ans = n;
        while (l <= r) {
            int m = (l + r)/2;
            vector<bool> mask(n);
            for (int i = curr + 1; i <= m; i++) mask[i] = 1;
            if (test_students(mask)) {
                ans = m;
                r = m - 1;
            } else {
                l = m + 1;
            }
        }
        curr = ans;
        if (curr != n) answer[curr] = 1;
    }
    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:63:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:79:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 336 KB Output is correct

Subtask #1
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 125 ms 336 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 102 ms 336 KB Output is correct (P=0.001, F=15.1, Q=18.1) -> 50.15 points
2 Correct 339 ms 336 KB Output is correct (P=0.005256, F=51.1, Q=54.2) -> 72.43 points
3 Correct 710 ms 336 KB Output is correct (P=0.011546, F=94.9, Q=108.0) -> 57.98 points
4 Correct 1666 ms 336 KB Output is correct (P=0.028545, F=191.5, Q=253.0) -> 39.39 points
5 Correct 2223 ms 336 KB Output is correct (P=0.039856, F=246.3, Q=352.5) -> 33.03 points
6 Correct 3772 ms 336 KB Output is correct (P=0.068648, F=366.2, Q=597.4) -> 25.53 points
7 Execution timed out 5177 ms 336 KB Time limit exceeded (wall clock)
8 Halted 0 ms 0 KB -