oj.uz

Submission #1103891

# Submission time Handle Problem Language Result Execution time Memory
1103891 2024-10-22T06:28:44 Z koukirocks COVID tests (CEOI24_covid) C++17
0 / 100
 4381 ms 336 KB 
#include <cassert>
#include <cstdio>
#include <string>
#include <vector>

/// 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.
std::vector<bool> find_positive() {
    std::vector<bool> answer(N);
    int L=0;
    while (L<=N-1) {
        int l=L,r=N-1;
        while (l<r) {
            int mid=l+r>>1;
            // printf("%d %d %d l mid r\n",l,mid,r);
            std::vector<bool> mask(N);
            for (int i=l;i<=mid;i++) {
                mask[i]=true;
            }
            bool ans = test_students(mask);
            if (ans) r=mid;
            else l=mid+1;
        }
        if (l!=N-1) {
            answer[l]=true;
        } else {
            std::vector<bool> mask(N);
            mask[l]=true;
            answer[l]=test_students(mask);
        }
        L=l+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 'std::vector<bool> find_positive()':
Main.cpp:45:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   45 |             int mid=l+r>>1;
      |                     ~^~
Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:29:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:69:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:85:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   85 |         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 70 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 53 ms 336 KB Output is correct (P=0.001, F=15.1, Q=18.1) -> 50.15 points
2 Correct 154 ms 336 KB Output is correct (P=0.005256, F=51.1, Q=54.2) -> 72.43 points
3 Correct 305 ms 336 KB Output is correct (P=0.011546, F=94.9, Q=108.4) -> 57.36 points
4 Correct 764 ms 336 KB Output is correct (P=0.028545, F=191.5, Q=254.5) -> 38.86 points
5 Correct 1111 ms 336 KB Output is correct (P=0.039856, F=246.3, Q=355.9) -> 32.37 points
6 Correct 1754 ms 336 KB Output is correct (P=0.068648, F=366.2, Q=606.7) -> 24.81 points
7 Correct 2789 ms 336 KB Output is correct (P=0.104571, F=490.3, Q=920.8) -> 19.95 points
8 Correct 4038 ms 336 KB Output is correct (P=0.158765, F=639.1, Q=1384.6) -> 15.88 points
9 Execution timed out 4381 ms 336 KB Time limit exceeded (wall clock)
10 Halted 0 ms 0 KB -