제출 #1363943

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1363943		Aviansh	COVID tests (CEOI24_covid)	C++20	30.02 / 100	683 ms	488 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(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.

int calcsize(double prob){
    if(prob==0.001){
        return 500;
    }
    else if(prob==0.005256){
        return 200;
    }
    else if(prob==0.011546){
        return 100;
    }
    else if(prob==0.028545){
        return 25;
    }
    else if(prob==0.039856){
        return 20;
    }
    else if(prob==0.068648){
        return 10;
    }
    else if(prob==0.104571){
        return 10;
    }
    else if(prob==0.158765){
        return 4;
    }
    else if(prob==0.2){
        return 4;
    }
    assert(0);
}

vector<int>solve(vector<vector<int>>&posset){
    int cnt = 0;
    for(vector<int>v:posset){
        cnt+=v.size();
    }
    int len = max(1,(((int)posset[0].size())/2));
    vector<vector<int>>sets;
    for(int x = 0;x<posset.size();x++){
        vector<int>pos = posset[x];
        for(int i = 0;i<pos.size();i+=len){
            int j = i+len-1;
            j=min(j,(int)pos.size()-1);
            //check i to j as one set
            vector<bool>quer(N,0);
            for(int z = i;z<=j;z++){
                quer[pos[z]]=1;
            }
            if(i+len>=pos.size()){
                if(sets.size()==0){
                    //no prev found
                    vector<int>cur;
                    for(int z = i;z<=j;z++){
                        cur.push_back(pos[z]);
                    }
                    sets.push_back(cur);
                    continue;
                }
            }
            if(test_students(quer)){
                vector<int>cur;
                for(int z = i;z<=j;z++){
                    cur.push_back(pos[z]);
                }
                sets.push_back(cur);
            }
        }
    }
    if(len==1){
        //i have the answer now
        vector<int>ans;
        for(vector<int>v:sets){
            //assert(v.size()==1);
            ans.push_back(v[0]);
        }
        return ans;
    }
    else if(len<=3){
        vector<int>ans;
        for(vector<int>v:sets){
            vector<vector<int>>temp = {v};
            vector<int>cur = solve(temp);
            ans.insert(ans.end(),cur.begin(),cur.end());
        }
        return ans;
    }
    vector<vector<int>>nx;
    for(vector<int>v:sets){
        vector<int>cur;
        for(int i : v){
            cur.push_back(i);
        }
        nx.push_back(cur);
    }
    if(nx.size()==0){
        return {};
    }
    int cnt2 = 0;
    for(vector<int>v:nx){
        cnt2+=v.size();
    }
    posset.clear();
    sets.clear();
    return solve(nx);
}

std::vector<bool> find_positive() {
    std::vector<bool> answer(N);
    vector<int>curr(N);
    vector<bool>temp(N,1);
    if(!test_students(temp)){
        return answer;
    }
    iota(curr.begin(),curr.end(),0);
    vector<vector<int>>tem={curr};
    int siz = calcsize(P);
    vector<vector<int>>pass;
    for(int i = 0;i<N;i+=siz){
        int j = i+siz-1;
        vector<int>t;
        for(int z = i;z<=j;z++){
            t.push_back(z);
        }
        pass.push_back(t);
    }
    vector<vector<int>>nx;
    vector<bool>quer(N);
    for(vector<int>v:pass){
        for(int i : v){
            quer[i]=1;
        }
        if(test_students(quer)){
            nx.push_back(v);
        }
        for(int i : v){
            quer[i]=0;
        }
    }
    vector<int>inds = solve(nx);
    for(int i : inds){
        answer[i]=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;
}

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:190:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  190 |     scanf("%d %lf %d", &N, &P, &T);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:206:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  206 |         scanf(" %c", &verdict);
      |         ~~~~~^~~~~~~~~~~~~~~~~

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