Submission #1040723

# Submission time Handle Problem Language Result Execution time Memory
1040723 2024-08-01T08:44:55 Z elazarkoren COVID tests (CEOI24_covid) C++17
36.85 / 100
2194 ms 600 KB
#include <bits/stdc++.h>
#define x first
#define y second
#define all(v) v.begin(), v.end()
#define chkmin(a, b) a = min(a, b)
#define chkmax(a, b) a = max(a, b)
using namespace std;
typedef long long ll;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pii;
typedef vector<pii> vii;
typedef vector<bool> vb;
/// 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 Solve(int l, int r, vb &ans) {
    vb test(n);
    fill(test.begin() + l, test.begin() + r, 1);
    bool b = test_students(test);
    if (!b) return;
    if (l + 1 == r) {
        ans[l] = 1;
        return;
    }
    Solve(l, (l + r) >> 1, ans);
    Solve((l + r) >> 1, r, ans);
}

mt19937 rng(0);

vb find_positive() {
    vb ans(n);
    int block = 1000;
    for (int i = 0; i < n; i += block) Solve(i, i + block, ans);

//    vb mask(n);
//    vi v(n);
//    iota(all(v), 0);
//    while (v.size() > 10) {
//        shuffle(all(v), rng);
//    }

//    Solve(0, n, answer);
//    vb test(n);
//    for (int i = 0; i < n; i++) {
//        test[i] = 1;
//        answer[i] = test_students(test);
//        test[i] = 0;
//    }
    return ans;
}

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++) {
        vb answer = find_positive();
        assert(answer.size() == (size_t)n);

        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:37:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:87:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   87 |     scanf("%d %lf %d", &n, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:103:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  103 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Runtime error 0 ms 344 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 10 ms 344 KB Output is correct
2 Correct 13 ms 344 KB Output is correct
3 Correct 11 ms 596 KB Output is correct
4 Correct 12 ms 344 KB Output is correct
5 Correct 13 ms 344 KB Output is correct
6 Correct 10 ms 344 KB Output is correct
7 Correct 9 ms 344 KB Output is correct
8 Correct 13 ms 344 KB Output is correct
9 Correct 12 ms 344 KB Output is correct
10 Correct 5 ms 344 KB Output is correct
11 Correct 7 ms 344 KB Output is correct
12 Correct 9 ms 344 KB Output is correct
13 Correct 10 ms 344 KB Output is correct
14 Correct 12 ms 344 KB Output is correct
15 Correct 12 ms 344 KB Output is correct
16 Correct 13 ms 344 KB Output is correct
17 Correct 0 ms 344 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 42 ms 344 KB Output is correct (P=0.001, F=15.1, Q=17.8) -> 52.47 points
2 Correct 163 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=78.0) -> 28.98 points
3 Correct 282 ms 600 KB Output is correct (P=0.011546, F=94.9, Q=150.1) -> 27.05 points
4 Correct 573 ms 344 KB Output is correct (P=0.028545, F=191.5, Q=304.1) -> 26.85 points
5 Correct 747 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=388.2) -> 27.24 points
6 Correct 1134 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=569.3) -> 27.96 points
7 Correct 1510 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=751.8) -> 28.72 points
8 Correct 1916 ms 504 KB Output is correct (P=0.158765, F=639.1, Q=967.7) -> 29.44 points
9 Correct 2194 ms 344 KB Output is correct (P=0.2, F=731.4, Q=1112.6) -> 29.18 points