제출 #1137713

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1137713		UmairAhmadMirza	COVID tests (CEOI24_covid)	C++20	35.60 / 100	1002 ms	408 KiB

Main

    #include <cassert>
    #include <cstdio>
    #include <string>
    #include <vector>
    #include <bits/stdc++.h>
    using namespace std;

    /// 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(vector<bool> mask) {
        assert(mask.size() == (size_t)N);

        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.
    vector<bool> find_positive() {
        vector<bool> answer(N);
        vector<bool> quer(N,0);
        int cur=0;
        int chn=2;
        if(P!=0)
            chn=(1+(1/P))*2;
        while(cur<N){
            int low=cur-1,high=min(N,cur+chn);
            while(high-low>1){
                int mid=(high+low)/2;
                if(high-mid>1)
                    mid=(high+mid)/2;
                for(int i=cur;i<=mid;i++)
                    quer[i]=1;
                bool b=test_students(quer);
                for(int i=cur;i<=mid;i++)
                    quer[i]=0;
                if(b)
                    high=mid;
                else
                    low=mid;
            }
            if(high!=min(N,cur+chn)){
                answer[high]=1;
                cur=high+1;
            }
            else
                cur+=chn;
        }
        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++) {
            vector<bool> 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;
    }

컴파일 시 표준 에러 (stderr) 메시지

Main.cpp: In function 'bool test_students(std::vector<bool>)':
Main.cpp:31:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |         scanf(" %c", &answer);
      |         ~~~~~^~~~~~~~~~~~~~~~
Main.cpp: In function 'int main()':
Main.cpp:76:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |         scanf("%d %lf %d", &N, &P, &T);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:92:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |             scanf(" %c", &verdict);
      |             ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 0 / 10
• Subtask 2: 35.6 / 90