oj.uz

Submission #1116553

# Submission time Handle Problem Language Result Execution time Memory
1116553 2024-11-21T19:47:19 Z ortsac COVID tests (CEOI24_covid) C++17
50.15 / 100
 7000 ms 504 KB 
//#pragma GCC optimize("O3")
#include <bits/stdc++.h>

using namespace std;

/// You may use:

// The number of students
int N;
int eQtd, eAparece;

// 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(const 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 qtd = 0;
    int curr = -1;
    while (curr < (n - 1)) {
        //if (qtd >= eQtd) {
        //    vector<bool> mask(n);
        //    for (int i = curr + 1; i < n; i++) mask[i] = 1;
        //    if (!test_students(mask)) break;
        //}
        int l = curr + 1, r = n - 1, ans = n;
        while (l <= r) {
            int m1 = (l + eAparece);
            int m2 = (l + r)/2;
            int m = min(m1, m2);
            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;
        qtd++;
    }
    return answer;
}

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

    // You may perform any extra initialization here.
    eQtd = (((double) N) * P);
    eAparece = 0;
    double pos = 1.0;
    while (pos > 0.5) {
        pos *= (1.0 - P);
        eAparece++;
    }
    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(const std::vector<bool>&)':
Main.cpp:30:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:74:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   74 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:96:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 336 KB Output is correct

Subtask #1
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 30 ms 336 KB Output is correct
2 Correct 25 ms 336 KB Output is correct
3 Correct 27 ms 336 KB Output is correct
4 Correct 18 ms 336 KB Output is correct
5 Correct 27 ms 336 KB Output is correct
6 Correct 32 ms 336 KB Output is correct
7 Correct 14 ms 336 KB Output is correct
8 Correct 18 ms 336 KB Output is correct
9 Correct 18 ms 336 KB Output is correct
10 Correct 11 ms 336 KB Output is correct
11 Correct 15 ms 336 KB Output is correct
12 Correct 20 ms 336 KB Output is correct
13 Correct 15 ms 336 KB Output is correct
14 Correct 17 ms 336 KB Output is correct
15 Correct 19 ms 336 KB Output is correct
16 Correct 38 ms 336 KB Output is correct
17 Execution timed out 7043 ms 504 KB Time limit exceeded
18 Halted 0 ms 0 KB -

Subtask #2
50.149999998 / 90.0

# Verdict Execution time Memory Grader output
1 Correct 106 ms 336 KB Output is correct (P=0.001, F=15.1, Q=18.1) -> 50.15 points
2 Correct 320 ms 336 KB Output is correct (P=0.005256, F=51.1, Q=51.6) -> 86.61 points
3 Correct 599 ms 336 KB Output is correct (P=0.011546, F=94.9, Q=94.6) -> 90.00 points
4 Correct 1190 ms 336 KB Output is correct (P=0.028545, F=191.5, Q=191.5) -> 90.00 points
5 Correct 1543 ms 336 KB Output is correct (P=0.039856, F=246.3, Q=247.8) -> 87.86 points
6 Correct 2249 ms 336 KB Output is correct (P=0.068648, F=366.2, Q=369.0) -> 87.33 points
7 Correct 3043 ms 336 KB Output is correct (P=0.104571, F=490.3, Q=494.3) -> 87.16 points
8 Correct 4199 ms 336 KB Output is correct (P=0.158765, F=639.1, Q=657.1) -> 80.89 points
9 Correct 4807 ms 336 KB Output is correct (P=0.2, F=731.4, Q=755.0) -> 79.71 points