Submission #1026347

#	Time	Username	Problem	Language	Result	Execution time	Memory
1026347		12345678	COVID tests (CEOI24_covid)	C++17	93.69 / 100	1886 ms	344 KiB

Main

#include <cassert>
#include <cstdio>
#include <string>
#include <vector>
#include <bits/stdc++.h>

using namespace std;

int N;
double P;

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';
}

std::vector<bool> find_positive(int sz) {
    vector<bool> qrs(N), res(N);
    vector<int> vs(N);
    int a=0, b;
    while (a<N)
    {
        b=min(a+sz-1, N-1);
        for (int i=0; i<N; i++) qrs[i]=0;
        for (int i=a; i<=b; i++) qrs[i]=1;
        if (!test_students(qrs))
        {
            a=b+1;
            continue;
        }
        int l=a, r=b;
        while (l<r)
        {
            int md=(l+r)/2;
            for (int i=0; i<N; i++) qrs[i]=0;
            for (int i=l; i<=md; i++) qrs[i]=1;
            if (test_students(qrs)) r=md;
            else l=md+1;
        }
        res[l]=1;
        a=l+1;
    }
    return res;
}

std::vector<bool> find_positive_brute_force() {
    std::vector<bool> answer(N);
    vector<bool> qrs(N);
    for (int i=0; i<N; i++) qrs[i]=1, answer[i]=test_students(qrs), qrs[i]=0;
    return answer;
}

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

    for (int i = 0; i < T; i++) {
        std::vector<bool> answer;
        if (P==0.001) answer=find_positive(500);
        else if (P==0.005256) answer=find_positive(125);
        else if (P==0.011546) answer=find_positive(59);
        else if (P==0.028545) answer=find_positive(25);
        else if (P==0.039856) answer=find_positive(17);
        else if (P==0.068648) answer=find_positive(10);
        else if (P==0.104571) answer=find_positive(7);
        else if (P==0.158765) answer=find_positive(4);
        else if (P==0.2) answer=find_positive(4);
        else answer=find_positive_brute_force();
        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;
}

//PNPPN
//0110011

Compilation message (stderr)

Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:23:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |     scanf(" %c", &answer);
      |     ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:65:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:89:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 10 / 10
• Subtask 2: 83.690000001 / 90