제출 #1137688

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1137688		Faisal_Saqib	COVID tests (CEOI24_covid)	C++20	29.52 / 100	931 ms	396 KiB

Main

//
// Created by faisal-saqib on 10:23 AM 1/20/25.
//
#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:
using namespace std;
int req_len=0;
void recur(int l,int r,vector<bool>&ans,vector<bool>&mk) {
    // int prob=P*(double)(r-l+2) + 1;
    bool pos=0;
    if ((r-l+1)>=req_len) {
        pos=1;
    }else {
    // pos=0;
     pos=test_students(mk);
    }
    if (pos) {
        if (l==r) {
            // if(test_students(mk))
            // {
            //     ans[l]=1;
            // }
            // else{
            //     ans[l]=0;
            // }
            // cnt++;
            return;
        }
        int mid=(l+r)/2;

        for (int p=mid+1;p<=r;p++)mk[p]=0;
        recur(l,mid,ans,mk);

        for (int p=l;p<=mid;p++)mk[p]=0;
        for (int p=mid+1;p<=r;p++)mk[p]=1;
        recur(mid+1,r,ans,mk);
    }
    else {
        for (int i = l; i <= r; i++) {ans[i]=0;}
    }
}

// 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() {
    req_len=(1.5/P);
    std::vector<bool> answer(N,1),mask(N,1);
    recur(0,N-1,answer,mask);
    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;
}

컴파일 시 표준 에러 (stderr) 메시지

Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:32:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |     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);
      |         ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 0 / 10
• Subtask 2: 29.52 / 90