Submission #1040734

# Submission time Handle Problem Language Result Execution time Memory
1040734 2024-08-01T08:49:01 Z elazarkoren COVID tests (CEOI24_covid) C++17
11.7 / 100
3898 ms 344 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 l = 0;
    while (l < n) {
        int begin = l, end = n;
        vb mask(n);
        fill(mask.begin() + l, mask.begin() + n, 1);
        if (!test_students(mask)) break;
        fill(mask.begin() + l, mask.begin() + n, 0);
        while (begin < end) {
            int mid = (begin + end) >> 1;
            fill(mask.begin() + l, mask.begin() + mid, 1);
            if (test_students(mask)) end = mid;
            else begin = mid + 1;
            fill(mask.begin() + l, mask.begin() + mid, 0);
        }
        ans[end - 1] = 1;
        l = end;
    }
    return ans;
//    int block = 1000;
//    for (int i = 0; i < n; i += block) Solve(i, i + block, ans);

//    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:98:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |     scanf("%d %lf %d", &n, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:114:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  114 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
# Verdict Execution time Memory Grader output
1 Incorrect 37 ms 344 KB Output isn't correct
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 23 ms 344 KB Output is correct (P=0.001, F=15.1, Q=10.7) -> 90.00 points
2 Correct 113 ms 344 KB Output is correct (P=0.005256, F=51.1, Q=53.0) -> 78.35 points
3 Correct 233 ms 344 KB Output is correct (P=0.011546, F=94.9, Q=114.4) -> 49.40 points
4 Correct 563 ms 344 KB Output is correct (P=0.028545, F=191.5, Q=279.4) -> 31.73 points
5 Correct 793 ms 344 KB Output is correct (P=0.039856, F=246.3, Q=392.4) -> 26.68 points
6 Correct 1346 ms 344 KB Output is correct (P=0.068648, F=366.2, Q=672.7) -> 20.70 points
7 Correct 2001 ms 344 KB Output is correct (P=0.104571, F=490.3, Q=1020.9) -> 16.89 points
8 Correct 3095 ms 344 KB Output is correct (P=0.158765, F=639.1, Q=1533.5) -> 13.64 points
9 Correct 3898 ms 344 KB Output is correct (P=0.2, F=731.4, Q=1954.5) -> 11.70 points